RU2829376C2 - Methods and systems for ultrasonic grinding of grain and degassing during metal casting - Google Patents

Abstract

FIELD: foundry.

SUBSTANCE: invention can be used in production of metal castings with controlled grain size. Metal article containing cast metal having submillimeter grain size and containing less than 0.5 wt.% of grain grinders. Relative elongation of said metal is 10–30% at tensile force of 100 lb/sq in, and tensile strength is 50–300 MPa. Introduction of vibration energy into molten metal during cooling of this metal makes it possible to grind metal grain to submillimeter size with introduction of less than 0.5 wt.% of grain grinders.

EFFECT: reduced tendency to occurrence of hot cracks in metal article, which will make it possible to increase rate of metal pouring and its further processing and, thus, to increase productivity.

8 cl, 21 dwg, 5 tbl

Description

Cross-reference to related applications

This application is related to U.S. Patent Application Ser. No. 62/372,592 (the contents of which are hereby incorporated herein in their entirety), filed August 9, 2016, and entitled "ULTRASONIC GRAIN REFINING AND DEGASSING PROCEDURES AND SYSTEMS FOR METAL CASTING." This application is related to U.S. Patent Application Ser. No. 62/295,333 (the contents of which are hereby incorporated herein in their entirety), filed February 15, 2016, and entitled "ULTRASONIC GRAIN REFINING AND DEGASSING FOR METAL CASTING." This application is related to U.S. Patent Application Ser. No. 62/267,507 (the contents of which are hereby incorporated by reference in their entirety), filed December 15, 2015, and entitled "ULTRASONIC GRAIN REFINING AND DEGASSING OF MOLTEN METAL." This application is related to U.S. Patent Application Ser. No. 62/113,882 (the contents of which are hereby incorporated by reference in their entirety), filed February 9, 2015, and entitled "ULTRASONIC GRAIN REFINING." This application is related to U.S. Patent Application Ser. No. 62/216,842 (the contents of which are hereby incorporated by reference in their entirety), filed September 10, 2015, and entitled "ULTRASONIC GRAIN REFINING ON A CONTINUOUS CASTING BELT."

Field of technology

The present invention relates to a method for producing metal castings with controlled grain size, a system for producing metal castings, and products obtained by metal casting.

State of the art

In metallurgy, technologies for casting molten metal to produce metal products in the form of continuous rods or cast products are being intensively developed. Both batch casting technologies and continuous casting technologies are well developed. Continuous casting has a number of advantages over batch casting, while both are widely used in industry.

In the production of continuous metal castings, molten metal passes from a reheat furnace into a series of runners and into a mold on a casting wheel where it is cast into a metal rod. The crystallized metal rod is removed from the casting wheel and sent to a rolling mill where it is rolled into a continuous rod. Depending on the intended use of the finished metal product in the form of a rod and the alloy composition, the rod may be cooled during rolling, or it may be cooled or quenched immediately after exiting the rolling mill to impart the desired mechanical and physical properties. For continuous processing of a metal product in the form of a rod or bar, techniques similar to those described in U.S. Patent No. 3,395,560 to Cofer et al. (the disclosure of which is hereby incorporated by this reference in its entirety) are used.

U.S. Patent No. 3,938,991 to Sperry et al. (the contents of which are hereby incorporated in their entirety) teaches that there is a long-recognized problem associated with producing "clean" cast metal articles. By "clean" cast metal articles is meant articles consisting of a metal or metal alloy containing the basic chemical elements-metals that provide specific conductivity, tensile strength, or ductility without the inclusion of certain impurities added for grain control purposes.

Grain refinement is a process in which the crystal size of a newly formed phase is reduced either chemically or physically/mechanically. In order to significantly reduce the grain size of a crystallized structure, grain refiners are usually added to the molten metal during crystallization, or during the transition from the liquid to the solid phase.

A specific example of the use of "grain refiners" is described, for example, in WIPO patent application WO/2003/033750 in the name of Boily et al. (the contents of which are hereby incorporated by this reference in their entirety). In the "Background of the Art" section of the '750 application, it is stated that in the aluminum industry, various grain refiners are commonly added to aluminum to produce a master alloy. Typical master alloys used in aluminum casting contain 1% to 10% titanium and 0.1% to 5% boron or carbon, the remainder being essentially aluminum or magnesium, with TiB ₂ or TiC particles dispersed in the aluminum matrix. According to the '750 application, master alloys containing titanium and boron can be produced by dissolving the required amounts of them in molten aluminum. This is achieved by reactions between molten aluminum and _KBF4 , _K2TiF6 at temperatures above 800 _° C. These complex halides react rapidly with molten aluminum and transfer titanium and boron into the melt.

The '750 application also states that as of 2002, this technology was used to produce commercial master alloys by nearly all grain refiner manufacturers. Grain refiners, often referred to as "inoculants," are still in use today. For example, one commercial master alloy supplier, TIBOR, states that precise control of casting structure is a key requirement for producing high-quality aluminum alloy products.

Prior to this invention, the use of grain refiners was considered the most effective way to ensure a fine and uniform crystal structure in the as-cast condition. More detailed information on the state of the art is given in the following documents (the contents of which are hereby incorporated in their entirety):

Abramov, O.V., (1998), "High-Intensity Ultrasonics," Gordon and Breach Science Publishers, Amsterdam, The Netherlands, pp. 523-552.

Alcoa, (2000), "New Process for Grain Refinement of Aluminum," DOE Project Final Report, Contract No. DE-FC07-98ID13665, September 22, 2000.

Cui, Y., Xu, C.L. and Han, Q., (2007), "Microstructure Improvement in Weld Metal Using Ultrasonic Vibrations, Advanced Engineering Materials," v. 9, No. 3, pp.161-163.

Eskin, G.I., (1998), "Ultrasonic Treatment of Light Alloy Melts," Gordon and Breach Science Publishers, Amsterdam, The Netherlands.

Eskin, G.I. (2002) "Effect of Ultrasonic Cavitation Treatment of the Melt on the Microstructure Evolution during Solidification of Aluminum Alloy Ingots," Zeitschrift Fur Metallkunde/Materials Research and Advanced Techniques, v.93, n.6, June, 2002, pp. 502-507.

Greer, A.L., (2004), "Grain Refinement of Aluminum Alloys," in Chu, M.G., Granger, D.A., and Han, Q., (eds.), "Solidification of Aluminum Alloys," Proceedings of a Symposium Sponsored by TMS (The Minerals, Metals & Materials Society), TMS, Warrendale, PA 15086-7528, pp. 131-145 .

Han, Q., (2007), "The Use of Power Ultrasound for Material Processing," Han, Q., Ludtka, G., and Zhai, Q., (eds), (2007), "Materials Processing under the Influence of External Fields," Proceedings of a Symposium Sponsored by TMS (The Minerals, Metals & Materials Society), TMS, Warrendale, PA 15086-7528, pp. 97-106.

Jackson, K. A., Hunt, J. D., and Uhlmann, D. R., and Seward, T. P., (1966), "On the Origin of Equiaxed Zone in Castings," Trans. Metall. Soc. AIME, v. 236, pp.149-158.

Jian, X., Xu, H., Meek, T.T., and Han, Q., (2005), "Effect of Power Ultrasound on Solidification of Aluminum A356 Alloy," Materials Letters, v. 59, no. 2-3, pp. 190-193.

Keles, O. and Dundar, M., (2007). "Aluminum Foil: Its Typical Quality Problems and Their Causes," Journal of Materials Processing Technology, v. 186, pp.125-137.

Liu, C., Pan, Y., and Aoyama, S., (1998), Proceedings of the 5 ^th International Conference on Semi-Solid Processing of Alloys and Composites, Eds.: Bhasin, A.K., Moore, J.J., Young, K.P., and Madison, S., Colorado School of Mines, Golden, CO, pp. 439-447.

Megy, J., (1999), "Molten Metal Treatment," US Patent No. 5,935,295, August, 1999

Megy, J., Granger, D.A., Sigworth, G.K., and Durst, C.R., (2000), "Effectiveness of In-Situ Aluminum Grain Refining Process," Light Metals, pp.1-6.

Cui et al., "Microstructure Improvement in Weld Metal Using Ultrasonic Vibrations," Advanced Engineering Materials, 2007, vol. 9, no. 3, pp. 161-163.

Han et al., "Grain Refining of Pure Aluminum," Light Metals 2012, pp. 967-971.

Prior to this invention, U.S. Patent Nos. 8,574,336 and 8,562,397 (the contents of which are incorporated herein by this reference in their entirety) disclose methods for reducing the amount of dissolved gas (and/or various impurities) in a molten metal bath (e.g., ultrasonic degassing), such as by introducing a purge gas into the molten metal bath in close proximity to an ultrasonic device. These patents will be referred to hereinafter as the "'336 patent" and the "'397 patent."

The essence of the invention

In one embodiment of the present invention, a device for processing molten metal is used, intended for attachment to a casting wheel of a casting machine. This device includes a unit mounted on the casting wheel, which includes at least one source of vibration energy, introducing vibration energy into the molten metal poured onto the casting wheel, during cooling of this metal located on the casting wheel, and a support device holding the source of vibration energy.

In one embodiment of the present invention, a method for producing a metal article is proposed. In carrying out this method, molten metal is placed in a containing element that is part of a casting machine. In carrying out this method, the molten metal located in the containing element is cooled and vibration energy is introduced into the molten metal located in the containing element.

In one embodiment of the present invention, a system for manufacturing a metal article is proposed. This system includes 1) the above-described device for processing molten metal and 2) a controller configured to receive data signals and output control signals and programmed using control algorithms that ensure the execution of any of the above-described method steps.

In one embodiment of the present invention, a device for processing molten metal is proposed. This device includes a source of molten metal, an ultrasonic degasser including an ultrasonic probe introduced into the molten metal, a casting mold intended for receiving the molten metal, a unit mounted on the casting mold that includes at least one source of oscillation energy introducing oscillation energy into the molten metal poured into the casting mold during cooling of this metal located in the casting mold, and a support device holding said at least one source of oscillation energy.

It should be understood that both the foregoing general description of the invention and the following detailed description are exemplary and not limiting of the invention.

Brief description of the drawings

A more complete appreciation of the invention and many of its inherent advantages will be readily apparent from a better understanding thereof as a result of a perusal of the following detailed description with reference to the accompanying drawings, of which:

Fig. 1 schematically shows a continuous casting installation corresponding to one embodiment of the invention;

Fig. 2 schematically shows the design of a casting wheel corresponding to one embodiment of the invention, in which at least one ultrasonic vibration energy source is used;

Fig. 3 schematically shows the design of a casting wheel corresponding to one embodiment of the invention, in which at least one source of vibration energy with a mechanical drive is used;

Fig. 3A is a schematic illustration of a hybrid casting wheel design according to one embodiment of the invention, in which both at least one ultrasonic vibration energy source and at least one mechanically driven vibration energy source are used;

Fig. 4 schematically shows the design of a casting wheel corresponding to one embodiment of the invention; this drawing shows a device with a vibration probe that directly affects the molten metal poured onto this wheel;

Fig. 5 schematically shows a stationary casting mold in which vibration energy sources according to the invention are used;

Fig. 6A is a sectional view of selected components of a vertical casting plant;

Fig. 6B shows a schematic cross-section of other components of the vertical casting plant;

Fig. 6C is a sectional view showing schematically other components of the vertical casting plant;

Fig. 6D is a sectional view showing schematically other components of the vertical casting plant;

Fig. 7 shows a schematic diagram of an exemplary computer system for the controls and controllers shown here;

Fig. 8 shows a block diagram of a method corresponding to one embodiment of the invention;

Fig. 9 schematically shows an embodiment of the invention in which both ultrasonic degassing and ultrasonic grinding of grain are used;

Fig. 10 shows the flow chart of the ACSR wire manufacturing process;

Fig. 11 shows the process flow diagram of the ACSS wire manufacturing process;

Fig. 12 shows the process flow diagram for manufacturing an aluminum strip;

Fig. 13 is a schematic side view illustrating the structure of a casting wheel according to one embodiment of the invention, in which a magnetostrictive element is used as the at least one ultrasonic vibration energy source;

Fig. 14 shows a schematic section of the magnetostrictive element shown in Fig. 13;

Fig. 15 shows microphotographs of aluminum alloy 1350 EC for comparison of grain structure in castings in the absence of chemical grain grinders, in the presence of grain grinders, and in the presence of only ultrasonic grain grinding;

Fig. 16 shows a table for comparing a conventional 1350 EC aluminum alloy rod (with chemical grain grinders) with a 1350 EC aluminum alloy rod (with ultrasonic grain grinding);

Fig. 17 shows a table comparing a conventional ACSR (chemical grain crusher) aluminum wire having a diameter of 0.130" (3.3 mm) with an ACSR (ultrasonic grain crusher) aluminum wire having a diameter of 0.130" (3.3 mm);

Fig. 18 shows a table for comparing a conventional rod made of aluminum alloy 8176 EEE (with chemical grain grinders) with a rod made of aluminum alloy 8176 EEE (with ultrasonic grain grinding);

Fig. 19 shows a table for comparing a conventional 5154 aluminum alloy rod (with chemical grain grinders) with a 5154 aluminum alloy rod (with ultrasonic grain grinding);

Fig. 20 is a table comparing conventional 5154 aluminum alloy strip (with chemical grain refiners) with 5154 aluminum alloy strip (with ultrasonic grain refiner); and

Fig. 21 shows a table indicating the properties of a rod made of aluminum alloy 5356 (with ultrasonic grain refinement).

Detailed description of implementation options

Grain refinement of metals and alloys is important for many reasons, including maximizing ingot casting speed, increasing hot crack resistance, minimizing elemental segregation, improving mechanical properties such as ductility, improving surface quality of formed products, and improving mold filling characteristics, as well as reducing the porosity of casting alloys. Grain refinement is typically one of the first processing steps in the production of metal and alloy products, particularly aluminum alloys and magnesium alloys, which are two lightweight materials that are increasingly used in the aerospace, defense, automotive, construction, and packaging industries. In addition, grain refinement is an important processing step in eliminating columnar grains and ensuring equiaxed grains in metal and alloy casting.

Grain refinement is a processing step during crystallization that reduces the size of the crystals of the solid phases by chemical, physical or mechanical means in order to facilitate casting of alloys and to reduce the number of defects that arise. Currently, in the production of aluminum products, grain refinement is performed using TIBOR, which results in the formation of an equiaxed grain structure in the crystallized aluminum. Prior to this invention, the only way to solve the long-recognized problem in the metal casting industry of the formation of columnar grains in metal castings was to use dopants or chemical "grain refiners". In addition, prior to this invention, the combination of ultrasonic degassing to remove impurities from the molten metal (prior to casting) and the above-mentioned ultrasonic grain refinement (i.e., the use of at least one source of vibration energy) was not used.

However, the use of TIBOR is associated with high costs, and when these modifiers are introduced into the melt, limitations arise in mechanical properties. In particular, limitations arise in plasticity, machinability and electrical conductivity.

Despite the expense, approximately 68% of aluminum produced in the United States is first cast into ingots and then processed into sheet, plate, extrusion, or foil. The direct chill (DC) semi-continuous casting process and the continuous casting (CC) process have been the mainstay of the aluminum industry, largely due to their robust nature and relative simplicity. One problem with the DC and CC processes is the formation of hot or cold cracks during ingot solidification. In fact, almost all ingots will crack (or fail to cast) unless grain refinement is used.

Productivity in these modern processes is still limited by the requirements to avoid cracking. Grain refinement is an effective way to reduce the tendency for hot cracking in the alloy and thus improve productivity. As a result, considerable effort is being spent on developing efficient grain refiners that can achieve the smallest possible grain sizes. If the grain size can be reduced to the sub-micron level, superplasticity can be achieved, which will not only allow alloys to be cast at significantly higher speeds, but also to be rolled/extruded at lower temperatures and at significantly higher speeds than ingots are processed today, resulting in significant cost and energy savings.

At present, almost all the aluminum cast worldwide, both from primary (approximately 20 billion kg) and from secondary and internal scrap (25 billion kg), is grain refined using heterogeneous crystallization centers of insoluble TiB ₂ with sizes of approximately a few microns in diameter, which allows obtaining a fine-grained structure in aluminum. One of the problems associated with the use of chemical grain refiners is their limited ability to refine grain. In fact, the use of chemical grain refiners provides a limited grain refinement in aluminum, with a transition from a columnar grain structure with an extension of slightly more than 2500 μm to equiaxed grains of less than 200 μm. It turned out that in aluminum alloys, the limiting size of equiaxed grains that can be obtained using commercially available chemical grain refiners is 100 μm.

If it is possible to further reduce the grain size, productivity can be increased significantly. Grain size at the submicron level leads to superplasticity, which greatly facilitates the forming of aluminum alloys at room temperatures.

Another problem associated with the use of chemical grain refiners is the occurrence of defects caused by such use. Although considered necessary for grain refinement in the current state of the art, the presence of insoluble foreign particles in aluminum is otherwise undesirable, especially in the form of clusters. Modern grain refiners, present in aluminum-based master alloys as compounds, are obtained during a complex process chain consisting of mining, beneficiation, and production. Master alloys currently in use often contain impurities in the form of potassium aluminum fluoride (KAlF) and aluminum oxide (dross), which are created during the normal manufacturing process of aluminum grain refiners. These lead to localized defects in the aluminum (e.g., "leaks" in beverage cans and "pinholes" in thin foil), abrasive wear of machining tools, and problems with the surface quality of the aluminum. Data from one aluminum cable manufacturer indicates that 25% of defects in the product are due to TiB ₂ particle accumulations, while another 25% of defects are due to slag that enters the aluminum during casting. TiB ₂ particle accumulations often cause wire breakage during extrusion, especially when the wire diameter is less than 8 mm.

Another problem with the use of chemical grain refiners is their cost. This is especially true in the case of magnesium ingot production using Zr grain refiners. Grain refinement using Zr grain refiners increases the cost of one kilogram of Mg castings produced by an additional $1.00. The cost of grain refiners for aluminum alloys is approximately $1.50 per kilogram.

Another problem associated with the use of chemical grain refiners is the reduction in electrical conductivity. The use of chemical grain refiners results in the presence of excessive amounts of Ti in the aluminum and causes a significant reduction in the electrical conductivity of pure aluminum used to manufacture cable. In order to maintain a certain level of conductivity, companies have to pay extra money to use purer aluminum in the manufacture of cable and wire.

In the last century, a number of grain refinement methods other than chemical ones have been explored. These methods include the use of physical fields such as magnetic and electromagnetic fields and the use of mechanical vibrations. High-intensity, low-amplitude ultrasonic vibrations are one of the physical/mechanical mechanisms that have been proposed as a method for grain refinement of metals and alloys without the use of foreign particles. However, experimental results, such as those reported by Cui et al. in 2007, cited above, were obtained for small metal ingots weighing up to a few pounds that were exposed to ultrasonic vibrations for a short period of time. Little research has been conducted on the use of high-intensity ultrasonic vibrations for grain refinement of ingots/piglets produced by CC or DC casting.

Some of the technical problems solved by the present invention in grain refinement are (1) introducing ultrasonic energy into the molten metal for a long time, (2) maintaining the natural oscillation frequency of the system at elevated temperatures, and (3) increasing the efficiency of ultrasonic grain refinement at high ultrasonic waveguide temperature. One of the solutions presented herein to accomplish these problems is improving the cooling of both the ultrasonic waveguide and the ingot (as described below).

In addition, another technical problem solved by the present invention is that as the purity of aluminum increases, it becomes more difficult to obtain equiaxed grains during crystallization. Even the use of externally introduced grain refiners, such as TiB (titanium boride), does not easily allow obtaining a structure with equiaxed grains in pure aluminum, such as the 1000, 1100 and 1300 series. However, the use of an innovative grain refinement technology, which is described here, has provided significant grain refinement.

One of the embodiments of the invention allows to a certain extent to prevent the occurrence of columnar grains without the need to introduce grain grinders. The effect of vibration energy on the molten metal when pouring into the casting mold allows to obtain grain sizes comparable to those obtained using existing grain grinders, for example, TIBOR ligatures, or smaller.

Embodiments of the present invention will be described herein using terminology commonly used by those skilled in the art when presenting their work. These terms will be given their ordinary meaning as used by those of ordinary skill in the fields of materials science, metallurgy, metal casting and metal processing. In the embodiments below, some terms will be used in a more specialized meaning. Despite this, the term "configured to" will be used herein to indicate the ability of the corresponding elements (presented herein, known or implied in the context of the prior art) to perform the function indicated after this term. The term "associated with" indicates that some object associated with a second object has the necessary structure to provide support to the first object for the purpose of maintaining its position relative to the second object (e.g., abutting, attaching, being at a predetermined distance, being located next to, providing adjacency, joining together, being separable, being removable from one another, being fastened together, being in sliding contact, providing rolling in contact) with or without direct fastening of the first and second objects together.

U.S. Patent No. 4,066,475 to Chia et al. (the contents of which are incorporated herein by this reference in their entirety) describes a continuous casting process. Generally speaking, Fig. 1 shows a continuous casting system having a casting apparatus 2 including a pouring trough 11 which directs molten metal into a circumferential groove created on a rotating forming ring 13. An endless flexible metal strip 14 extends around a portion of the forming ring 13 and also around a portion of each of the rollers 15 included in the roller set and providing positioning of this strip, as a result of which this groove in the forming ring 13 and the overlying metal strip 14 form a mold for continuous casting. A cooling system is provided for cooling the device and providing controlled crystallization of the molten metal during its transport on the rotating forming ring 13. The cooling system includes a plurality of side collectors 17, 18, 19, located on the side of the forming ring 13, as well as internal 20 and external 21 collectors, respectively, located on the inner and outer sides of the metal strip 14 in the region where it passes around the forming ring. In order to control the cooling of the device and the rate of crystallization of the molten metal, a network of 24 pipelines is connected, having corresponding valves, which ensures the supply of coolant to various collectors and its removal from these collectors.

In such a design, the molten metal is fed from the pouring trough 11 into the casting mold, crystallizes and partially cools during its transportation due to the circulation of the coolant in the cooling system. The solid cast rod 25 is removed from the casting wheel and fed to the conveyor 27, which transports it to the rolling mill 28. It should be noted that the cast rod 25 is cooled only to a degree sufficient for its solidification, and it has an elevated temperature to make it possible to directly perform the rolling operation for it. The rolling mill 28 can include successively installed stands in which successive rolling of the rod occurs with the production of a continuous rod 30, which has, in essence, an unchanged, circular cross-section.

1 and 2, a controller 500 is shown that controls various portions of the continuous casting system illustrated herein, as discussed in more detail below. The controller 500 may include one or more processors containing programmed instructions (i.e., algorithms) for controlling the operation of the continuous casting system and its components.

In one embodiment of the invention, as shown in Fig. 2, the casting installation 2 includes a casting wheel 30 having a containing element 32 (e.g., a trough or channel) into which molten metal is poured (e.g., during a casting process), and a device 34 for handling molten metal. A strip 36 (e.g., a flexible metal strip made of steel) limits the possible location of the molten metal by the containing element 32 (i.e., the channel). Rollers 38 allow the device 34 for handling molten metal to remain stationary on the rotating casting wheel when molten metal crystallizes in the channel of this wheel and is transported away from this device. In one embodiment of the invention, the device 34 for processing molten metal includes a unit 42 mounted on the casting wheel 30. The unit 42 includes at least one source 40 of vibration energy (for example, a vibrator 40) and a housing 44 (i.e., a support device) holding the source 40 of vibration energy. The unit 42 includes at least one cooling channel 46 through which a cooling medium is transported. Between the flexible strip 36 and the housing 44, a seal 44a is installed, attached to the lower side of this housing, which allows the cooling medium to flow from the cooling channel along the side of the flexible strip opposite to its side on which the molten metal located in the channel of the casting wheel is located. The air cleaner 52 directs air (for safety) in such a way that all water flowing out of the cooling channel will be directed away from the source of molten metal. The seal 44a can be made of a number of materials, including ethylene propylene copolymer, Viton, Buna N (nitrile rubber), neoprene, silicone rubber, urethane, fluorosilicone, polytetrafluoroethylene, as well as other known sealing materials. In one embodiment of the invention, the positioning of the device 34 for processing molten metal relative to the rotating casting wheel 30 is provided by a guide device (for example, rollers 38). The cooling medium provides cooling of the molten metal located in the containing element 32 and / or the mentioned at least one source of oscillation energy 40. In one embodiment of the invention, the components of the device 34 for processing molten metal, including the body, can be made of metal, for example, titanium, stainless steel, low-carbon steel or H13 steel, other materials that can withstand high temperatures, ceramics, composite or polymer. The components of the device 34 for processing molten metal can be made of one or more of the following: niobium, niobium alloy, titanium, titanium alloy, tantalum, tantalum alloy, copper, copper alloy, rhenium, rhenium alloy, steel, molybdenum, molybdenum alloy, stainless steel and ceramics. The ceramics can be silicon nitride, such as aluminum silicon oxynitride or SIALON.

In one embodiment of the invention, when the molten metal passes under the metal strip 36 located under the vibrator 40, the vibration energy is introduced into it at the beginning of its cooling and crystallization. In one embodiment of the invention, the vibration energy is acted upon by means of ultrasonic transducers created, for example, on the basis of piezoelectric devices. In one embodiment of the invention, the vibration energy is acted upon by means of ultrasonic transducers created, for example, on the basis of magnetostrictive transducers. In one embodiment of the invention, the vibration energy is acted upon by means of vibrators with a mechanical drive (to be discussed later). In one embodiment, the vibration energy makes it possible to create a multitude of small crystallization nuclei, which ensures the production of a metal article with a fine grain.

In one embodiment of the invention, ultrasonic grain refinement includes the use of ultrasonic energy (and/or other vibrational energy) to refine grain. Although the invention is not limited to any particular theoretical basis, one theoretical basis is that the introduction of vibrational energy (e.g., ultrasonic energy) into a molten or solidifying alloy can lead to the occurrence of nonlinear phenomena, such as cavitation, sonic flows, and radiation pressure. These nonlinear phenomena can be used to nucleate new grains and destroy dendrites during solidification of the alloy.

According to this theory, the grain refinement process can be divided into two stages 1) the emergence of crystallization centers and 2) the growth of the newly formed solid phase from the liquid. At the stage of the emergence of crystallization centers, spherical crystallization centers arise. These crystallization centers develop into dendrites at the growth stage. Unidirectional growth of dendrites leads to the formation of columnar grains, which can cause the occurrence of hot cracks/cold cracks and uneven distribution of secondary phases. This, in turn, can lead to deterioration of casting properties. On the other hand, uniform growth of dendrites in all directions (which is possible with the use of the present invention) leads to the formation of equiaxed grains. Castings/ingots containing small and equiaxed grains have excellent formability.

According to this theory, when the temperature in the alloy is below the liquidus temperature, crystallization centers can occur if the size of the solid phase nuclei is larger than the critical size given in the following equation:

Where - critical size, - interphase energy at the interface between the solid and liquid phases and - Gibbs free energy associated with the transformation of a unit volume of the liquid phase into a solid.

According to this theory, the Gibbs free energy, , decreases with increasing size of solid phase nuclei if their sizes are larger , which indicates that the growth of the solid phase nucleus is thermodynamically more favorable. Under such conditions, the solid phase nuclei become stable crystallization centers. However, the homogeneous formation of crystallization centers with sizes greater than occurs only under extreme conditions that require high supercooling in the melt.

According to this theory, the crystallization centers created during crystallization can grow into grains of the solid phase known as dendrites. Dendrites can also be broken into many small fragments when exposed to vibrational energy. The resulting dendritic fragments can grow into new grains and lead to the formation of small grains, which allows the creation of a structure with equiaxed grains.

Without intending to be limited by any theory, a relatively small degree of supercooling of the molten metal (e.g., less than 2, 5, 10, or 15°C) at the top of the channel of the casting wheel 30 (e.g., at the bottom of the strip 36) results in the appearance of a layer of small crystallization centers of pure aluminum (or other metal or alloy) at the steel strip. Vibrational energy (e.g., ultrasonic vibrations or vibrations created by mechanical means) facilitates the development of these crystallization centers, which are then used as modifiers during crystallization, which results in the formation of a uniform grain structure. Accordingly, in one embodiment of the invention, the cooling method used ensures that a small degree of supercooling at the top of the channel of the casting wheel 30 at the steel strip will result in the appearance of small crystallization centers of the molten metal as its cooling continues. The vibrations acting on the strip 36 serve to distribute these crystallization centers in the molten metal located in the channel of the casting wheel 30 and/or can serve to destroy dendrites that arise in the supercooled layer. For example, the vibration energy introduced into the molten metal during its cooling can, due to cavitation (see below), destroy dendrites with the creation of new crystallization centers. These crystallization centers and fragments of dendrites can then be used to create (assist in the creation of) equiaxed grains in the casting mold during crystallization, which leads to the emergence of a homogeneous grain structure.

In other words, ultrasonic vibrations transmitted to supercooled liquid metal create crystallization initiation sites in metals or metal alloys, which leads to a decrease in grain size. Crystallization initiation sites can be created by the action of vibration energy, as described above, in order to destroy dendrites, which creates a plurality of crystallization centers in the molten metal that are independent of foreign impurities. According to one aspect, the channel of the casting wheel 30 can be made of a refractory metal or other material that can withstand high temperatures, such as copper, cast iron and steel, niobium, niobium and molybdenum, tantalum, tungsten, rhenium and their alloys, including one or more chemical elements such as silicon, oxygen or nitrogen, which can increase the melting point of these materials.

In one embodiment of the invention, the source of creating ultrasonic vibrations in the source of 40 vibration energy provides a power of 1.5 kW at a sound frequency of 20 kHz. This invention is not limited to these values of power and frequency. The values of power and frequency of ultrasound can be selected from a large range, although the ranges that are given below are of interest.

Power

In general, the power values are in the range of 50 to 5000 W for each sonotrode, depending on its size or the size of the probe. These power values are typically applied in the sonotrode to ensure that the power density at the tip of the sonotrode is above 100 W/cm ² , which can be considered the threshold for creating cavitation in molten metals, depending on the cooling rate of the molten metal, the type of molten metal and other factors. Power values in this zone can be in the range of 50-5000 W, 100-3000 W, 500-2000 W, 1000-1500 W, or any intermediate or overlapping range. Higher power values are possible for a larger probe/sonotrode and lower power values for a smaller probe. In various embodiments of the invention, the power density when exposed to oscillation energy may be in the range of 10 W/ ^cm2 -500 W/ ^cm2 , 20 W/ ^cm2 -400 W/ ^cm2 , 30 W/ ^cm2 -300 W/ ^cm2 , 50 W/ ^cm2 -200 W/ ^cm2 or 70 W/ ^cm2 -150 W/ ^cm2 , or in any intermediate or overlapping ranges within the specified values.

Frequency

Generally speaking, a frequency in the range of 5-400 kHz (or any intermediate range) may be used. Alternatively, a frequency in the range of 10-30 kHz (or any intermediate range) may be used. The influencing frequency may be in the range of 5-400 kHz, 10-30 kHz, 15-25 kHz, 10-200 kHz, or 50-100 kHz, or any intermediate or overlapping ranges within these values.

In one embodiment of the invention, vibrators 40, numbering at least one, are installed in such a way that they are connected to cooling channels 46, these vibrators in the case of an ultrasonic probe (or sonotrode, piezoelectric transducer, ultrasound emitter or magnetostrictive element) included in the ultrasonic transducer, provide passage of oscillation energy generated by ultrasound through the cooling medium, as well as through the unit 42 and the strip 36, into the liquid metal. In one embodiment of the invention, the ultrasound energy is supplied from a transducer capable of converting electric current into mechanical energy, which leads to the occurrence of an oscillation frequency above 20 kHz (for example, up to 400 kHz), wherein the ultrasound energy is supplied from one or both piezoelectric elements or magnetostrictive elements.

In one embodiment of the invention, the ultrasonic probe is mounted in the cooling channel 46 so that it contacts the liquid cooling medium. In one embodiment of the invention, the distance from the tip of the ultrasonic probe to the strip 36, if any, is variable. This distance, for example, can be less than 1 mm, less than 2 mm, less than 5 mm, less than 1 cm, less than 2 cm, less than 5 cm, less than 10 cm, less than 20 cm or less than 50 cm. In one embodiment of the invention, several ultrasonic probes or a set of ultrasonic probes are mounted in the cooling channel 46 so that they contact the liquid cooling medium. In one embodiment of the invention, the ultrasonic probe can be attached to the wall of the unit 42.

According to one aspect of the invention, piezoelectric transducers that provide vibration energy may consist of a ceramic material that is sandwiched between electrodes that have attachment points for creating an electrical contact. When a voltage is applied to the ceramic through the electrodes, it expands and contracts at ultrasonic frequencies. In one embodiment of the invention, a piezoelectric transducer that serves as a vibration energy source 40 is attached to an amplifier that transmits vibrations to a probe. U.S. Patent No. 9,061,928 (the contents of which are incorporated herein by this reference in their entirety) describes an ultrasonic transducer assembly that includes an ultrasonic transducer, an ultrasonic amplifier, an ultrasonic probe, and a cooling unit for the amplifier. The ultrasonic amplifier in the '928 patent is coupled to the ultrasonic transducer to amplify the sound energy created by this transducer and transmit the amplified sound energy to the ultrasonic probe. The amplifier design of the '928 patent is usefully applied in the present invention to supply power to ultrasonic probes that directly contact or indirectly act upon the liquid cooling medium discussed above.

In fact, in one embodiment of the invention, an ultrasound amplifier is used in the ultrasound range to amplify, or increase, the vibration energy created by the piezoelectric transducer. The amplifier does not increase or decrease the vibration frequency, it increases the vibration amplitude. (If the amplifier is installed on the reverse side, it also compacts the vibration energy). In one embodiment of the invention, the amplifier is installed between the piezoelectric transducer and the probe in connection with them. For the case of using the amplifier in ultrasonic grinding of grain, the following are listed by way of example the steps of the method illustrating the use of an amplifier with a piezoelectric vibration energy source:

1) An electric current is supplied to the piezoelectric transducer. After the electric current is supplied, the ceramic parts inside the transducer begin to expand and contract, which leads to the conversion of electrical energy into mechanical energy.

2) These vibrations in one embodiment of the invention are then transmitted to an amplifier, which amplifies, or increases, these mechanical vibrations.

3) The amplified, or magnified, vibrations from the amplifier in one embodiment are then propagated into the probe. As a result, the probe vibrates at ultrasound frequencies, which leads to the creation of cavitation.

4) Cavitation created by the vibrating probe acts on the casting strip, which in one embodiment comes into contact with the molten metal.

5) Cavitation in one variant destroys dendrites and creates a structure with equiaxed grains.

Referring to Fig. 2, the probe is connected to a cooling medium flowing through the device 34 for processing molten metal. Cavitation created in the cooling medium by means of the probe vibrating at ultrasound frequencies acts on the strip 36, which contacts the molten aluminum located in the containing element 32.

In one embodiment of the invention, the vibration energy can be introduced using magnetostrictive transducers serving as a source 40 of vibration energy. In one embodiment, the magnetostrictive transducer serving as a source 40 of vibration energy has the same arrangement as the block of piezoelectric transducers shown in Fig. 2, with the only difference that the source of ultrasound causing the surface to vibrate with an ultrasound frequency is at least one magnetostrictive transducer, and not at least one piezoelectric element. Fig. 13 shows the design of a casting wheel corresponding to one embodiment of the invention, in which a magnetostrictive element 40a is used for said at least one ultrasonic source of vibration energy. In this embodiment of the invention, the magnetostrictive transducer(s) 40a vibrates a probe (not shown in the side view shown in Fig. 13) connected to a cooling medium, for example at a frequency of 30 kHz, although other frequencies can be used as described below. In another embodiment of the invention, the magnetostrictive transducer 40a vibrates a lower plate 40b shown in Fig. 14, which shows a schematic section of the device 34 for processing molten metal with a lower plate 40b that is connected to a cooling medium (shown in Fig. 14).

Typically, magnetostrictive transducers comprise a plurality of plates of a material that will expand and contract after an electromagnetic field is generated. More specifically, magnetostrictive transducers suitable for the present invention may comprise, in one embodiment, a plurality of nickel plates (or plates of another magnetostrictive material) or layers arranged in parallel with one edge of each layer attached to the bottom of a process vessel or other surface that is to be made to vibrate. A wire winding is created around the magnetostrictive material to create a magnetic field. The magnetic field is created, for example, when an electric current is passed through the wire winding. This magnetic field causes the magnetostrictive material to contract or lengthen, which results in the introduction of a sound wave into a fluid medium in contact with the expanding and contracting magnetostrictive material. Typically, the ultrasound frequency generated by magnetostrictive transducers suitable for the invention is in the range of 20-200 kHz. Higher or lower frequencies can be used, depending on the natural frequency of the magnetostrictive element.

One of the materials most widely used in magnetostrictive transducers is nickel. When a voltage is applied to the transducer, nickel expands and contracts at ultrasonic frequencies. In one embodiment of the invention, nickel plates are directly soldered with silver solder to a stainless steel plate. Referring to Fig. 2, in a magnetostrictive transducer, it is the surface of the stainless steel plate that vibrates at ultrasonic frequencies and is directly connected (as a probe) to a cooling medium flowing through a device 34 for processing molten metal. Cavitation created in the cooling medium by the plate vibrating at ultrasonic frequencies then acts on a strip 36, which contacts molten aluminum located in a containing member 32.

U.S. Patent No. 7,462,960 (the contents of which are hereby incorporated in their entirety) describes an ultrasonic transducer actuator having a giant magnetostrictive element. Accordingly, in one embodiment of the invention, the magnetostrictive element may be made from rare earth alloy materials, such as Terfenol-D and composites thereof, which have an unusually large magnetostrictive effect compared to early transition metals such as iron (Fe), cobalt (Co), and nickel (Ni). Alternatively, in one embodiment of the invention, the magnetostrictive element may be made from iron (Fe), cobalt (Co), and nickel (Ni).

Alternatively, in one embodiment of the invention, the magnetostrictive element may be made from one or more of the following alloys: iron and terbium; iron and praseodymium; iron, terbium and praseodymium; iron and dysprosium; iron, terbium and dysprosium; iron, praseodymium and dysprosium; iron, terbium, praseodymium and dysprosium; iron and erbium; iron and samarium; iron, erbium and samarium; iron, samarium and dysprosium; iron and holmium; iron, samarium and holmium; or mixtures thereof.

A magnetostrictive transducer is described in U.S. Patent No. 4,158,368 (the contents of which are hereby incorporated by this reference in their entirety). As described therein, and as is applicable to the present invention, the magnetostrictive transducer may include a plunger made of a material having negative magnetostriction, which is mounted in a housing. A magnetostrictive transducer is described in U.S. Patent No. 5,588,466 (the contents of which are hereby incorporated by this reference in their entirety). As described therein, and as is applicable to the present invention, a magnetostrictive layer is applied to a flexible element, for example a flexible element fixed as a beam. The flexible element deflects under the action of an external magnetic field. As described in the '466 patent, and suitable for the present invention, a thin magnetostrictive layer consisting of (Tb(1-x)Dy(x)Fe ₂ can be used as the magnetostrictive element. A magnetostrictive transducer is described in U.S. Patent No. 4,599,591 (the contents of which are hereby incorporated by this reference in their entirety). As described therein, and suitable for the present invention, the magnetostrictive transducer can use a magnetostrictive material and a plurality of windings connected to a plurality of current sources having a phase relationship such that a rotation of the magnetic induction vector occurs in the magnetostrictive material. A magnetostrictive transducer is described in U.S. Patent No. 4,986,808 (the contents of which are hereby incorporated by this reference in their entirety). As described therein, and suitable for the present invention, the magnetostrictive transducer can include a plurality of elongated strips of magnetostrictive material, each of the strips have a near end, a far end and a substantially V-shaped longitudinal section, that is, the halves forming the letter V extend in the longitudinal direction, and each strip is attached to the adjacent strip at said near end and far end to obtain a solid, substantially rigid column having a central axis and ribs extending in the radial direction from this axis.

Fig. 3 schematically shows another embodiment of the invention, this drawing shows a structure with a mechanical principle of creating oscillations for introducing low-frequency oscillation energy into the molten metal located in the channel of the casting wheel 30. In one embodiment of the invention, the oscillation energy is provided by mechanical oscillations created by a converter or other mechanical excitation means. As is known in the art, a vibrator is a mechanical device that creates oscillations. Oscillations are often created using an electric motor with an asymmetrical mass on the drive shaft. Some mechanical vibrators consist of an electromagnetic drive and a stirrer shaft that provides excitation due to reciprocating vertical movement. In one embodiment of the invention, the oscillation energy is supplied from a vibrator (or other component) that can use mechanical energy to create an oscillation frequency of up to 20 kHz (but not limited to this value) and preferably in the range of 5-10 kHz.

Regardless of the mechanism for creating the vibrations, the attachment of a vibrator (piezoelectric transducer, magnetostrictive transducer or vibrator with a mechanical drive) to the housing 44 means that the vibration energy can be transferred to the molten metal located in the channel below the unit 42.

Mechanical vibrators that are useful in the invention can operate in the range of 8000-15000 oscillations per minute, although higher and lower frequencies can be used. In one embodiment of the invention, the oscillating mechanism is configured to oscillate in the range of 565-5000 oscillations per minute. In one embodiment of the invention, the oscillating mechanism is configured to oscillate at an even lower frequency, starting from a fraction of a oscillation per second and up to 565 oscillations per second. Ranges of mechanically generated oscillations suitable for the invention include, for example, 6000-9000 oscillations per minute, 8000-10000 oscillations per minute, 10000-12000 oscillations per minute, 12000-15000 oscillations per minute and 15000-25000 oscillations per minute. Ranges of mechanically generated vibrations suitable for the invention, which are indicated in the literature, include, for example, ranges of 133-250 Hz, 200-283 Hz (12,000-17,000 vibrations per minute) and 4-250 Hz. In addition, mechanically generated vibrations of various types can be communicated to the casting wheel 30 or the housing 44 by means of a simple hammer or plunger device, periodically actuated to strike these wheels or housings. Generally speaking, mechanical vibrations can have a range of up to 10 kHz. Accordingly, ranges suitable for mechanical vibrations used in the invention include: 0-10 kHz, 10 Hz - 4000 Hz, 20 Hz - 2000 Hz, 40 Hz - 1000 Hz, 100 Hz - 500 Hz and intermediate and combined ranges within the specified values, including the preferred range of 565-5000 Hz.

Although the invention has been described above using its variants that use ultrasound and a mechanical drive, it is not limited to one or the other of these ranges, but can be used with a wide range of vibration energy, up to 400 kHz, including sources with a single frequency or multiple frequencies. In addition, a combination of sources (ultrasonic sources and sources with a mechanical drive, different ultrasound sources or different sources with a mechanical drive, or different sources of sound energy, which will be described below) can be used.

As shown in Fig. 3, the casting installation 2 includes a casting wheel 30 having inside a containing element 32 (for example, a tray or a channel) into which molten metal is poured, and a device 34 for handling molten metal. A strip 36 (for example, steel) limits the possible location of the molten metal by the containing element 32 (i.e., the channel). Also, as in the above case, rollers 38 allow the device 34 for handling molten metal to remain stationary when molten metal 1) crystallizes in the channel of the casting wheel and 2) is transported away from the device 34 for handling molten metal.

In the cooling channel 46, a cooling medium flows. As before, the pneumatic cleaner 52 directs the air (for safety) in such a way that all water flowing out of the cooling channel will be directed away from the source of molten metal. As before, the positioning of the device 34 for processing molten metal relative to the rotating casting wheel 30 is ensured by a device with a rolling function (for example, rollers 38). The cooling medium ensures cooling of the molten metal and the mentioned at least one source 40 of vibration energy (shown in Fig. 3 as a mechanical vibrator 40).

When the molten metal passes under the metal strip 36, located under the mechanical vibrator 40, when this metal begins to cool and crystallize, the energy of vibrations created mechanically is introduced into it. The energy of vibrations created mechanically, in one embodiment, allows for the creation of many small crystallization nuclei, which allows for the production of a metal product with a fine grain.

In one embodiment of the invention, vibrators 40, numbering at least one, are installed in such a way that they are connected to cooling channels 46, and in the case if these are mechanical vibrators, through the cooling medium, as well as through the unit 42 and the strip 36, they introduce into the liquid metal the energy of vibrations created mechanically. In one embodiment of the invention, the head of the mechanical vibrator is introduced into the cooling channel 46 for contact with the liquid cooling medium. In one embodiment of the invention, several heads of mechanical vibrators or a set of heads of mechanical vibrators can be introduced into the cooling channel 46 for contact with the liquid cooling medium. In one embodiment of the invention, the head of the mechanical vibrator can be attached to the wall of the unit 42.

Without intending to be limited by any particular theory, a relatively small degree of undercooling (e.g., less than 10°C) at the bottom of the channel of the casting wheel 30 results in the formation of a layer of small crystallization centers of pure aluminum (or another metal or alloy). The mechanically created vibrations create these crystallization centers, which are then used as modifiers during crystallization, which results in the formation of a uniform grain structure. Accordingly, in one embodiment of the invention, the cooling method used ensures that a small degree of undercooling at the bottom of the channel results in the formation of a layer of small crystallization centers of the material being processed. The mechanically created vibrations distribute these crystallization centers in a direction away from the bottom of the channel and/or can serve to break up dendrites that form in the undercooled layer. These crystallization centers and dendrite fragments are then used to create equiaxed grains in the casting mold during crystallization, which results in the formation of a uniform grain structure.

In other words, in one embodiment of the invention, mechanically generated vibrations transmitted to the liquid metal create crystallization initiation sites in metals or metal alloys, which results in grain refinement. As in the above case, the channel of the casting wheel 30 can be made of a refractory metal or other material that can withstand high temperatures, such as copper, cast iron and steel, niobium, niobium and molybdenum, tantalum, tungsten, rhenium and their alloys, including one or more chemical elements such as silicon, oxygen or nitrogen, which can increase the melting point of these materials.

Fig. 3A schematically shows a hybrid design of a casting wheel according to one embodiment of the invention, in which at least one ultrasonic vibration energy source and at least one mechanically driven vibration energy source (e.g., a mechanically driven vibrator) are used. Elements similar to those shown in Fig. 3 are similar elements performing similar functions as those indicated above. For example, the containing element 32 (e.g., a tray or channel) indicated in Fig. 3A is located in the illustrated casting wheel onto which molten metal is poured. Also, as in the above case, the strip (not shown in Fig. 3A) limits the possible location of the molten metal by the containing element 32. In this case, in this embodiment of the invention, both the ultrasonic source (sources) of oscillation energy and the source (sources) of oscillation energy with a mechanical drive are selectively activated, and they can be activated separately or together in order to obtain oscillations that, when transmitted to the liquid metal, create places of the beginning of crystallization in metals or metal alloys for grinding grain. In various embodiments of the invention, various combinations of the ultrasonic source (sources) of oscillation energy and the source (sources) of oscillation energy with a mechanical drive can be created and used.

Aspects of the invention

According to one aspect of the invention, the means containing the molten metal can be exposed to vibration energy during cooling (from mechanically driven vibrators creating low-frequency vibrations in the range of 8000-15000 vibrations per minute, or up to 10 kHz, and/or ultrasonic vibrators with a frequency in the range of 5-400 kHz). According to one aspect of the invention, it is possible to be exposed to vibration energy having a plurality of individual frequencies. According to one aspect of the invention, the vibration energy can be applied to various metals and metal alloys, including but not limited to those listed below: aluminum, copper, gold, iron, nickel, platinum, silver, zinc, magnesium, titanium, niobium, tungsten, manganese, as well as alloys and combinations thereof; metal alloys including brass (copper/zinc), bronze (copper/tin), steel (iron/carbon), chromalloy (chromium), stainless steel (steel/chromium), tool steel (carbon/tungsten/manganese), titanium (iron/aluminium) and standardized grades of aluminium alloys including 1100, 1350, 2024, 2224, 5052, 5154, 5356, 5183, 6101, 6201, 6061, 6053, 7050, 7075, 8XXX series; copper alloys including bronze (specified above) and copper alloyed with a combination of zinc, tin, aluminium, silicon, nickel, silver; magnesium alloyed with aluminium, zinc, manganese, silicon, copper, nickel, zirconium, beryllium, calcium, cerium, neodymium, strontium, tin, yttrium, rare earth metals; iron and iron alloyed with chromium, carbon, silicon, chromium, nickel, potassium, plutonium, zinc, zirconium, titanium, lead, magnesium, tin, scandium; and other alloys and combinations thereof.

According to one aspect of the invention, the oscillation energy (from mechanically driven vibrators creating low-frequency oscillations in the range of 8000-15000 oscillations per minute, or up to 10 kHz, and/or ultrasonic vibrators with a frequency in the range of 5-400 kHz) is introduced through a liquid medium in contact with the strip into the crystallizing metal located under the device 34 for processing molten metal. According to one aspect of the invention, the oscillation energy in the range of 565-5000 Hz is introduced mechanically. According to one aspect of the invention, the oscillation energy at even lower frequencies is created mechanically, starting from a fraction of an oscillation per second and up to 565 oscillations per second. According to one aspect of the invention, the oscillation energy at frequencies in the range of 5 kHz - 400 kHz is created using ultrasound. According to one aspect of the invention, the oscillation energy is introduced through the housing 44 containing the oscillation energy source 40. The body 44 is connected to other structural elements, such as a strip 36 or rollers 38, which contact either the walls of the channel or directly the molten metal. According to one aspect of the invention, this mechanical connection allows the vibration energy to be transferred from the vibration energy source to the molten metal during its cooling.

According to one aspect, the cooling medium may be a liquid, such as water. According to one aspect, the cooling medium may be a gas, such as compressed air or nitrogen. According to one aspect of the invention, the cooling medium may be a phase-change material. Preferably, the cooling medium flow rate is sufficient to supercool the metal adjacent to the strip 36 (with an excess of the liquidus temperature of the alloy by less than 5-10°C, or even below the liquidus temperature).

According to one aspect of the invention, equiaxed grains in a cast article are obtained without the need to add impurity particles, such as titanium boride, to the metal or metal alloy to increase the number of grains and promote uniform heterogeneous crystallization. According to one aspect of the invention, instead of using modifiers to create crystallization initiation sites, vibration energy can be used.

During operation, the molten metal, which has a temperature significantly higher than the liquidus temperature of the alloy, flows under the force of gravity into the channel of the casting wheel 30 and passes under the device 34 for processing the molten metal, where it is exposed to the energy of vibrations (i.e., ultrasonic vibrations or vibrations created by mechanical means). The temperature of the molten metal entering the channel of the casting wheel depends, among other things, on the selected type of alloy, the pouring speed and the dimensions of this channel in the casting wheel. In the case of aluminum alloys, the casting temperature may be in the range of 1220 F (660°C) - 1350 F (732°C), with preferred subranges being, for example, 1220 F (660°C) - 1300 F (704°C), 1220 F (660°C) - 1280 F (693°C), 1220 F (660°C) - 1270 F (688°C), 1220 F (660°C) - 1340 F (727°C), 1240 F (671°C) - 1320 F (716°C), 1250 F (677°C) - 1300 F (704°C), 1260 F (682°C) - 1310 F (710°C), 1270 F (688°C) -1320 F (716°C), 1320 F (716°C) -1330 F (721°C), overlapping and intermediate ranges are also suitable and variations of +/- 10 degrees F are possible. The channel of the casting wheel 30 is cooled to ensure that the molten metal therein is at a temperature close to the subliquidus temperature (e.g., less than 5-10°C above the liquidus temperature of the alloy, or even below the liquidus temperature, although the pouring temperature may be significantly above these 10°C). During operation, the temperature of the atmosphere surrounding the molten metal can be controlled by using a jacket (not shown) that is filled with, or through which these gases are blown, for example, an inert gas such as Ar, He, or nitrogen. On the casting wheel 30, the molten metal is generally in a state of maintaining a constant temperature, at which it changes from a liquid to a solid state.

As a result of supercooling at a level close to the subliquidus temperature, the crystallization rates are not low enough to ensure equilibrium at the solidus-liquidus boundary, which in turn leads to variations in the chemical composition in the cast rod. The non-uniformity of the chemical composition leads to liquation. In addition, the degree of liquation is directly related to the diffusion coefficients of the various chemical elements in the molten metal, as well as to the heat transfer rates. Another type of liquation occurs in places where the constituents with lower melting points crystallize first.

In embodiments of the invention that employ ultrasonic or mechanically generated vibrations, the vibration energy excites the molten metal as it cools. In this embodiment, the vibration energy excites and effectively mixes the molten metal. In one embodiment, the mechanically generated vibration energy serves to continuously mix the molten metal as it cools. In various alloy casting processes, it is desirable to achieve high silicon concentrations in the aluminum alloy. However, at higher concentrations, silicon may precipitate as phases. By "re-mixing" these precipitated phases back into the molten state, it is possible to at least partially return elemental silicon back into solution. Alternatively, even if precipitated phases remain, the mixing will prevent the precipitated silicon phases from segregating, which would increase the abrasive wear of the metal matrix and rollers located below, when viewed in the direction of the process.

In various metal alloy systems, the same type of phenomenon occurs whereby one component of the alloy (usually the component with the higher melting point) separates out in pure form, resulting in what is essentially a "contamination" of the alloy with particles of the pure component. Generally speaking, when an alloy is cast, liquation occurs, resulting in a non-uniform concentration of the dissolved component in the casting. This may be caused by a variety of processes. Micro-liquation, which occurs in areas comparable in size to the distances between the branches of a dendritic filament, is thought to result from the concentration in the first solid phase to form being lower than the final equilibrium concentration, causing excess dissolved component to pass into the liquid, resulting in a higher concentration in the later solid phase. Macro-liquation occurs in areas comparable in size to the casting. This may be caused by a number of complex processes, including shrinkage during casting crystallization and changes in liquid density during separation of the dissolved component. It is desirable to prevent liquation during casting in order to obtain a crystallized blank with unchanged material properties.

Thus, the alloys indicated above are among the specific alloys that can benefit from vibration energy treatment according to the invention.

Other configurations

The present invention is not limited to the application of vibration energy exclusively to the channel structures described herein. Generally speaking, vibration energy (from mechanically driven vibrators producing low frequencies in the range of up to 10 kHz and/or at frequencies ultrasound in the range of 5-400 kHz) can cause the onset of crystallization in those areas of the casting process where the molten metal begins to cool with a transition from a molten state to a solid state (i.e., a state of maintaining a constant temperature). If you look at it another way, in the invention, in its various embodiments, the use of oscillation energy from a plurality of different sources is combined with temperature control in such a way that the molten metal located near the cooling surface has a temperature close to the liquidus temperature of the alloy. In these embodiments, the temperature of the molten metal located in the channel or at the strip 36 of the casting wheel 30 is low enough to cause the onset of crystallization and crystal growth (formation of dendrites), wherein the oscillation energy creates crystallization centers and / or destroys dendrites that may arise on the surface of the channel of the casting wheel 30.

In one embodiment of the invention, the advantages provided by the casting process can be obtained without using the vibration energy sources, or using them in a continuous mode. In one embodiment of the invention, by controlling the power supply to the vibration energy sources, these sources can be used with programmed on/off cycles providing a relative duration of inclusion in the ranges of 0-100%, 10-50%, 50-90%, 40-60%, 45-55% and any intermediate ranges.

In another embodiment of the invention, the vibration energy (ultrasonic or mechanically generated) is directly introduced into the molten aluminum poured onto the casting wheel before it contacts the strip 36. The direct impact of the vibration energy creates pressure fluctuations in the melt. The direct impact of the ultrasound energy as vibration energy on the molten metal can cause cavitation in the liquid melt.

Without intending to be limited by any particular theory, cavitation consists of the formation of small discontinuities or voids in liquids, which then grow, pulsate or collapse. Voids are formed as a result of the action of tensile stresses created by the sound wave in the rarefied phase. If tensile stresses (or negative pressure) continue to act after the formation of a void, it will increase in size to several times its original size. During cavitation in an ultrasound field, many voids are formed simultaneously at distances shorter than the ultrasound wavelength. In this case, the bubbles of the voids retain their spherical shape. The subsequent behavior of the cavitation bubbles is highly variable: a small proportion of bubbles merge to form larger bubbles, but almost all of them collapse under the action of the sound wave at the compression stage. During compression, some of these voids may collapse due to the action of compressive stresses. As a result, when these voids collapse, strong shock waves are generated in the melt. Accordingly, in one embodiment of the invention, the shock waves created by the vibration energy serve to destroy dendrites and other growing crystallization centers, which leads to the formation of new crystallization centers, which, in turn, leads to the formation of a structure with equiaxed grains. In addition, in another embodiment of the invention, continuous ultrasonic vibrations can effectively increase the homogeneity of the resulting crystallization centers, further facilitating the formation of an equiaxed structure. In another embodiment of the invention, intermittent ultrasound vibrations or vibrations created mechanically can effectively increase the homogeneity of the resulting crystallization centers, further facilitating the formation of an equiaxed structure.

In Fig. 4 there is shown schematically the construction of a casting wheel corresponding to one embodiment of the invention, namely, with a device 66 having a vibroprobe (not shown) directly introduced into the molten metal poured onto the casting wheel 60. The probe will have a design that is similar to that used in the art for ultrasonic degassing. In Fig. 4 there is shown a roller 62 pressing a strip 68 against the rim of the casting wheel 60. The device 66 with the vibroprobe directly or indirectly introduces vibration energy (ultrasonic energy or energy created mechanically) into the molten metal poured into a channel (not shown) of the casting wheel 60. As the casting wheel 60 rotates counterclockwise, the molten metal passes under the roller 62 and comes into contact with a device 64 for cooling the molten metal, the use of which is optional. This device 64 may be similar to the unit 42 shown in Fig. 2 and 3, but will not have vibrators 40. This device 64 may be similar to the device 34 for processing molten metal shown in Fig. 3, but will not have mechanical vibrators 40.

In this embodiment, as shown in Fig. 4, in the device for processing molten metal used in the casting installation, at least one source of vibration energy (i.e., the device 66 with a vibration probe) is used, which introduces vibration energy by means of a probe introduced into the molten metal poured onto the casting wheel (preferably, but not necessarily, directly into the molten metal poured onto the casting wheel), when this metal located on the casting wheel is cooled. A support device holds the source of vibration energy (the device 66 with a vibration probe) in place.

In another embodiment of the invention, vibration energy can be introduced into the molten metal when it is cooled using air or gas used as a medium in sound vibration generators. Sound vibration generators (e.g., sound amplifiers) can be used to generate and transmit sound waves into the molten metal. In this embodiment, the ultrasonic vibrators or vibrators with a mechanical drive discussed above will be replaced or supplemented by sound vibration generators. Sound amplifiers suitable for the invention will create sound vibrations from 1 to 20,000 Hz. Sound vibrations above or below this range can be used. For example, sound vibrations in the ranges of 0.5-20 Hz, 10-500 Hz, 200-2000 Hz, 1000-5000 Hz, 2000-10000 Hz, 5000-14000 Hz, 10000-16000 Hz, 14000-20000 Hz and 18000-25000 Hz can be used. Electroacoustic transducers can be used to generate and transmit sound energy.

In one embodiment of the invention, the sound energy may be introduced through a gaseous medium directly into the molten metal, wherein the sound energy creates vibrations in the molten metal. In one embodiment of the invention, the sound energy may be introduced through a gaseous medium indirectly into the molten metal, wherein the sound energy causes vibrations of the strip 36 or other support element containing the molten metal, which, in turn, create vibrations in the molten metal.

In addition to the use of the vibration energy treatment provided by the present invention in the above-described wheel-based continuous casting systems, the invention is also useful in stationary casting molds and vertical casting installations.

In the case of stationary installations, the molten metal will be poured into a stationary casting mold 62, such as shown in Fig. 5, which itself has a device 34 for processing the molten metal (shown schematically). As a result, the vibration energy (from vibrators with a mechanical drive, creating a low frequency in the range of up to 10 kHz during operation, and / or at an ultrasound frequency in the range of 5-400 kHz) can cause the onset of crystallization in those places of the stationary casting mold where the molten metal begins to cool with a transition from a molten state to a solid state (i.e., a state of maintaining a constant temperature).

6A to 6D, selected components of a vertical casting apparatus are shown. More detailed information on these components and other features of the vertical casting apparatus can be found in U.S. Patent No. 3,520,352 (the contents of which are incorporated herein by this reference in their entirety). As shown in Figs. 6A to 6D, the vertical casting apparatus includes a cavity 213 for casting molten metal, which in the embodiment shown is generally square, but may be circular, elliptical, polygonal, or any other suitable shape, and which is defined by vertical abutting first wall portions 215 and second, or corner, wall portions 217 located at the top of the casting mold. The walls 215 and the corner elements 217 of the casting cavity are surrounded by a housing 219 located at a distance therefrom and designed to contain a fluid. The casing 219 is adapted to receive a cooling fluid, such as water, through an inlet channel 221 and to discharge the cooling fluid through an outlet channel 223.

While the first portions 215 of the walls are preferably made of a material with high thermal conductivity, such as copper, the second, or corner, portions 217 of the walls consist of a less thermally conductive material, such as ceramics, for example. As shown in Fig. 6A - Fig. 6D, the corner portions 217 of the walls have a generally L-shaped cross-section, or a cross-section in the form of a corner, and the vertical ends of each corner element approach each other when viewed in a vertically downward direction. Thus, the corner element 217 ends in the casting mold at some suitable level above its outlet end, which is located between the cross-sections shown.

In operation, molten metal flows from an intermediate casting device 245 into a casting mold that moves back and forth in a vertical direction, and the cast thread of metal is continuously removed from the casting mold. First, the molten metal is cooled in the casting mold by contact with its colder walls, in what can be considered the first cooling zone. In this zone, heat is quickly removed from the molten metal, and it is assumed that a solid crust is formed around the centrally located bath of molten metal.

In one embodiment of the invention, the position of the vibration energy sources (vibrators 40, for simplicity, schematically shown only in Fig. 6D) will depend on the design of the casing 219 intended to contain the fluid, and in the preferred case they will be installed in the cooling medium circulating in this casing. The vibration energy (from mechanically driven vibrators, when operating creating a low frequency in the range of 8000-15000 vibrations per minute, and / or at an ultrasound frequency in the range of 5-400 kHz and / or from the above-mentioned sound amplifiers) will cause the onset of crystallization in those areas of the casting process where the molten metal begins to cool from the molten state to the solid state (i.e. the state of maintaining a constant temperature), as the molten metal passes from the liquid to the solid state, and as the cast thread of metal is continuously removed from the metal casting cavity 213.

In one embodiment of the invention, the ultrasonic grain refinement described above is combined with the ultrasonic degassing mentioned above to remove impurities from a molten metal bath prior to casting. Fig. 9 schematically shows an embodiment of the invention in which both ultrasonic degassing and ultrasonic grain refinement are used. As shown here, the source of molten metal is a furnace. The molten metal from the furnace is transported to a launder. In one embodiment of the invention, an ultrasonic degasser is installed in the path of the launder before the molten metal is fed to a casting machine (e.g., a casting wheel) containing an ultrasonic grain refiner (not shown). In one embodiment, the grain refinement in the casting machine need not occur in the ultrasonic frequency range, but may instead be performed at one or more other mechanically generated vibration frequencies that are specified elsewhere in this description.

The '336 patent describes the following degassers suitable for various embodiments of the present invention, but ultrasonic degassers are not limited to the specific embodiments thereof described below. One suitable degasser may be an ultrasonic device having an ultrasonic transducer; an elongated probe, a first end of which is attached to the ultrasonic transducer and a tip of the probe is located at a second end of the probe; and a system for supplying a purge gas, wherein the system may include an inlet for the purge gas and an outlet for the purge gas. In some embodiments, the outlet for the purge gas may be located at a distance of no more than about 10 cm (5 cm, 1 cm) from the tip of the elongated probe, while in other embodiments, the outlet for the purge gas may be located at this tip. In addition, the ultrasonic device may include a plurality of probe assemblies and/or a plurality of probes for each ultrasonic transducer.

The '397 patent describes the following degassers that are also suitable for various embodiments of the present invention, but ultrasonic degassers are not limited to the specific embodiments thereof described below. One suitable degasser may be an ultrasonic device having an ultrasonic transducer; a probe attached to the ultrasonic transducer, wherein the probe has a tip; and a gas supply system, wherein the system comprises a gas inlet, a gas flow path through the probe, and a gas outlet at the tip of the probe. In one embodiment, the probe may be an elongated probe, a first end of which is attached to the ultrasonic transducer and a second end of which has a tip of this probe. In addition, the probe may comprise stainless steel, titanium, niobium, ceramic, etc., or a combination of any of these materials. In another embodiment, the ultrasonic probe may be a single probe made of SIALON material, with an integrated gas supply system passing through it. In yet another embodiment, the ultrasonic device may comprise a plurality of probe assemblies and/or a plurality of probes for each ultrasonic transducer.

In one embodiment of the invention, the ultrasonic grinding of grain is supplemented by ultrasonic degassing, which uses, for example, the ultrasonic probes discussed above. In various examples of ultrasonic degassing, a purge gas is introduced into the molten metal, for example, using the probes discussed above, at a flow rate of from about 1 to about 50 l/min. By indicating that the flow rate is in the range of about 1 to about 50 L/min, it is meant that the flow rate may be about 1, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 13, about 14, about 15, about 16, about 17, about 18, about 19, about 20, about 21, about 22, about 23, about 24, about 25, about 26, about 27, about 28, about 29, about 30, about 31, about 32, about 33, about 34, about 35, about 36, about 37, about 38, about 39, about 40, about 41, about 42, about 43, about 44, about 45, approximately 46, approximately 47, approximately 48, approximately 49, or approximately 50 l/min. In addition, the flow rate may be within any range from approximately 1 to approximately 50 l/min (for example, the flow rate is in the range from approximately 2 to approximately 20 l/min), and this also includes any combination of ranges between approximately 1 and approximately 50 l/min. Intermediate ranges are also possible. Likewise, all other ranges discussed herein should be understood in a similar manner.

In embodiments of the present invention relating to ultrasonic degassing and ultrasonic grain grinding, systems, methods and/or devices for ultrasonic degassing of molten metals, including (but not limited to) aluminum, copper, steel, zinc, magnesium, etc., or combinations of these and other metals (e.g., alloys), may be provided. When processing or casting articles, a container may be required to hold a bath of molten metal, and elevated temperatures can be maintained in this vessel. For example, the temperature of molten copper can be maintained at about 1100°C, while the temperature of molten aluminum can be maintained at about 750°C.

As used herein, the term "vessel", "molten metal vessel", etc. means any container that can contain molten metal, including a vessel, crucible, tray, trough, furnace, ladle, etc. The terms "vessel" and "molten metal vessel" are used when referring to a batch mode, a continuous mode, a semi-continuous mode, etc., and, for example, in cases where the molten metal is generally stationary (e.g., this is often the case with a crucible) and in cases where the molten metal is generally in motion (e.g., this is often the case with a ladle).

Various devices or equipment may be used to monitor, check or change the conditions of the molten metal in the vessel, as well as to finally obtain or cast the required metal product. These devices or equipment are required to have increased resistance to the elevated temperatures present in the molten metal vessels, the advantage being a longer service life and the inability of their material to react with the molten metal, or a limited ability to react, regardless of what kind of metal it is (or what is included in its composition) - aluminum, copper, steel, zinc, magnesium, etc.

In addition, one or more gases may be dissolved in the molten metals, and these gases may adversely affect the final production or casting of the desired metal article and/or the resulting physical properties of the article itself. For example, the gas dissolved in the molten metal may include hydrogen, oxygen, nitrogen, sulfur dioxide, etc., or combinations thereof. In some circumstances, it may be advantageous to remove the gas or reduce the amount of gas in the molten metal. As an example, dissolved hydrogen can be detrimental to the casting of aluminum (copper or other metal or alloy), so the properties of finished articles made from aluminum (copper or other metal or alloy) can be improved by reducing the amount of hydrogen entering the molten aluminum (copper or other metal or alloy) bath. Hydrogen dissolved at levels greater than 0.2 ppm, greater than 0.3 ppm, or greater than 0.5 ppm by weight may adversely affect the casting speed and quality of the resulting aluminum (copper or other metal or alloy) rods or other articles. Hydrogen may enter the molten aluminum (copper or other metal or alloy) bath from its presence in the atmosphere above the bath, or may be present in the aluminum (copper or other metal or alloy)-containing feedstock that creates the molten aluminum (copper or other metal or alloy) bath.

Attempts to reduce the amount of gases dissolved in a molten metal bath have not always been entirely successful. Often in the past, these processes have involved the use of additional and expensive equipment as well as potentially hazardous materials. For example, a process used in the metal casting industry to reduce the amount of dissolved gas in the molten metal may employ rotors made of a material such as graphite and place these rotors in the molten metal bath. Chlorine gas may also be added to the molten metal bath at locations near the rotors. Although the addition of chlorine gas may be successful in reducing, for example, the amount of hydrogen dissolved in the molten metal bath in some situations, this conventional process has significant disadvantages, not the least of which are cost, complexity, and the use of potentially hazardous and potentially environmentally harmful chlorine gas.

In addition, impurities may be present in the molten metals, and these impurities may adversely affect the final production and casting of the desired metal article and/or the resulting physical properties of the article itself. For example, impurities present in the molten metal may include an alkali or other metal, the presence of which in the molten metal is neither necessary nor desirable. Various metal alloys may have a small percentage of certain metals, and such metals will not be considered impurities. As non-limiting examples, impurities may include lithium, sodium, potassium, lead, etc., or combinations thereof. Various impurities may enter the molten metal bath (aluminum, copper, or other metal or alloy) due to their presence in the feed metal source material that creates the molten metal bath.

In embodiments of this invention relating to ultrasonic degassing and ultrasonic grain refinement, methods for reducing the amount of dissolved gas present in a molten metal bath, or, in other words, methods for degassing molten metals, may be provided. One such method may comprise operating an ultrasonic device located in a molten metal bath and introducing a purge gas into the bath in close proximity to the device. The dissolved gas may optionally comprise oxygen, hydrogen, sulfur dioxide, etc., or combinations thereof. For example, the dissolved gas may optionally comprise hydrogen. The molten metal bath may comprise aluminum, copper, zinc, steel, magnesium, etc., or mixtures and/or combinations thereof (e.g., including various alloys of aluminum, copper, zinc, steel, magnesium, etc.). In some embodiments relating to ultrasonic degassing and ultrasonic grain refinement, the molten metal bath may comprise aluminum, and in other embodiments, the molten metal bath may comprise copper. Accordingly, the molten metal forming the bath may be aluminum, or alternatively, the molten metal may be copper.

In addition, embodiments of this invention may provide methods for reducing the amount of impurity present in a molten metal bath or, in other words, methods for removing impurities. One such method, related to ultrasonic degassing and ultrasonic grain refinement, may comprise operating an ultrasonic device located in a molten metal bath and introducing a purge gas into the bath in close proximity to the device. The impurity may optionally comprise lithium, sodium, potassium, lead, etc., or combinations thereof. For example, the impurity may optionally comprise lithium or, alternatively, sodium. The molten metal bath may comprise aluminum, copper, zinc, steel, magnesium, etc., or mixtures and/or combinations thereof (e.g., including various alloys of aluminum, copper, zinc, steel, magnesium, etc.). In some embodiments, the molten metal bath may comprise aluminum, and in other embodiments, the molten metal bath may comprise copper. Accordingly, the molten metal forming the bath may be aluminum, or alternatively, the molten metal may be copper.

The purge gas used in the ultrasonic degassing and ultrasonic grain milling used in the degassing and/or impurity removal methods disclosed herein may comprise one or more of, but is not limited to, nitrogen, helium, neon, argon, krypton, and/or xenon. It is contemplated that any suitable gas may be used as the purge gas, provided that the gas is slightly reactive with or slightly soluble in the particular metal(s) in the molten metal bath. In addition, mixtures or combinations of gases may be used. In some embodiments disclosed herein, the purge gas may optionally comprise an inert gas; alternatively, the purge gas may optionally comprise a noble gas; alternatively, the purge gas may optionally comprise helium, neon, argon, or a combination thereof; alternatively, the purge gas may optionally comprise helium; Alternatively, the purge gas may optionally comprise neon; or, alternatively, the purge gas may optionally comprise argon. In addition, applicants contemplate that in some embodiments, conventional degassing technology may be used in conjunction with the ultrasonic degassing processes described herein. Accordingly, the purge gas may in some embodiments further comprise chlorine gas, for example, chlorine gas may be used as a purge gas alone or in combination with at least one of nitrogen, helium, neon, argon, krypton, and/or xenon.

However, in other embodiments of this invention, the methods relating to ultrasonic degassing and ultrasonic grain refinement for the purpose of degassing or reducing the amount of gas dissolved in a molten metal bath may be carried out with little or no chlorine gas present. As used herein, "little" means that no more than 5% by weight of chlorine gas may be used in the total amount of purge gas used. In some embodiments, the methods described herein may comprise introducing a purge gas, and the purge gas may be selected from the group consisting of nitrogen, helium, neon, argon, krypton, xenon, and combinations thereof.

The amount of purge gas introduced into the molten metal bath may vary depending on a number of factors. Often, in ultrasonic degassing and ultrasonic grain milling, the amount of purge gas introduced in the method of degassing molten metals (and/or the method of removing impurities from molten metals) according to embodiments of this invention may be in the range of from about 0.1 to about 150 standard liters per minute (L/min). In some embodiments, the amount of purge gas introduced may be in the range of from about 0.5 to about 100 l/min, from about 1 to about 100 l/min, from about 1 to about 50 l/min, from about 1 to about 35 l/min, from about 1 to about 25 l/min, from about 1 to about 10 l/min, from about 1.5 to about 20 l/min, from about 2 to about 15 l/min, or from about 2 to about 10 l/min. This volumetric flow rate is indicated in standard liters per minute, i.e., at standard temperature (21.1 °C) and pressure (101 kPa).

In continuous and semi-continuous molten metal operations, the amount of purge gas introduced into the molten metal bath may be varied based on molten metal output or throughput. Accordingly, the amount of purge gas introduced during the method of degassing molten metals (and/or the method of removing impurities from molten metals) of such ultrasonic degassing and ultrasonic grain refining embodiments may be in the range of from about 10 to about 500 ml/hour of purge gas per kg/hour of molten metal (ml purge gas/kg molten metal). In some embodiments, the ratio of the volumetric flow rate of purge gas to the molten metal output volume may be in the range of from about 10 to about 400 ml/kg; alternatively, from about 15 to about 300 ml/kg; alternatively, from about 20 to about 250 ml/kg; alternatively, from about 30 to about 200 ml/kg; alternatively, from about 40 to about 150 ml/kg; or, alternatively, from about 50 to about 125 ml/kg. Also, as in the above case, the volumetric flow rate of the purge gas is specified at standard temperature (21.1°C) and pressure (101 kPa).

Methods for degassing molten metals according to embodiments of this invention and relating to ultrasonic degassing and ultrasonic grain refinement can provide for the effective removal of more than about 10 weight percent of the dissolved gas present in the molten metal bath, i.e., the amount of dissolved gas in the molten metal bath can be reduced by more than about 10 weight percent of its amount present before applying the degassing. In some embodiments, the amount of dissolved gas present can be reduced by more than about 15 weight percent, more than about 20 weight percent, more than about 25 weight percent, more than about 35 weight percent, more than about 50 weight percent, more than about 75 weight percent, or more than about 80 weight percent of the amount of dissolved gas present before applying the degassing method. For example, if the dissolved gas is hydrogen, hydrogen levels in a molten metal bath containing aluminum or copper greater than about 0.3 ppm, 0.4 ppm, or 0.5 ppm (by weight) can be unfavorable, and often the hydrogen content in the molten metal can be about 0.4 ppm, about 0.5 ppm, about 0.6 ppm, about 0.7 ppm, about 0.8 ppm, about 0.9 ppm, about 1 ppm, about 1.5 ppm, about 2 ppm, or more than 2 ppm. It is contemplated that use of the methods described for embodiments of this invention can reduce the amount of dissolved gas in a molten metal bath to a level of less than about 0.4 ppm; alternatively, to a level of less than about 0.3 ppm; alternatively, to a level of less than about 0.2 ppm; alternatively, to a level in the range of from about 0.1 to about 0.4 ppm; alternatively, to a level in the range of from about 0.1 to about 0.3 ppm; or, alternatively, to a level in the range of from about 0.2 to about 0.3 ppm. In these and other embodiments, the dissolved gas may optionally comprise hydrogen, and the molten metal bath may optionally comprise aluminum and/or copper.

Embodiments of this invention relating to ultrasonic degassing and ultrasonic grain milling, which provide methods for degassing (e.g., reducing the amount of dissolved gas in a vessel containing a molten metal bath) or methods for removing impurities, may comprise using an ultrasonic device located in a molten metal bath. The ultrasonic device may comprise an ultrasonic transducer and an elongated probe having a first end and a second end. The first end may be attached to the ultrasonic transducer, and a tip may be located at the second end, and the elongated probe on the tip may contain niobium. Illustrative and non-limiting examples of ultrasonic devices that may be used in the processes and methods discussed herein are described in detail below.

In the case of an ultrasonic degassing process or an impurity removal process, the purging gas can be introduced into the molten metal bath, for example, at a location near the ultrasonic device. In one embodiment, the purging gas can be introduced into the molten metal bath at a location near the tip of the ultrasonic device. In one embodiment, the purging gas can be introduced into the molten metal bath at a distance of no more than about 1 meter from the tip of the ultrasonic device, such as at a distance of no more than about 100 cm, no more than about 50 cm, no more than about 40 cm, no more than about 30 cm, no more than about 25 cm, or no more than about 20 cm from the tip of the ultrasonic device. In some embodiments, the purging gas can be introduced into the molten metal bath at a distance of no more than about 15 cm from the tip of the ultrasonic device; alternatively, at a distance of no more than about 10 cm; alternatively, at a distance of no more than about 8 cm; alternatively, at a distance of no more than about 5 cm; alternatively, at a distance of no more than about 3 cm; alternatively, at a distance of no more than about 2 cm; or, alternatively, at a distance of no more than about 1 cm. In a particular embodiment, the purging gas may be introduced into the molten metal bath near or through the tip of the ultrasonic device.

Without intending to be limited by this theory, the use of an ultrasonic device and the introduction of a purging gas in close proximity thereof result in a significant reduction in the amount of dissolved gas in a vessel containing a molten metal bath. The ultrasonic energy created by the ultrasonic device can create cavitation bubbles in the melt into which the dissolved gas can diffuse. However, in the absence of a purging gas, many of the cavitation bubbles may collapse before reaching the surface of the molten metal bath. The purging gas can reduce the number of cavitation bubbles that collapse before reaching the surface and/or can increase the size of the bubbles containing the dissolved gas and/or can increase the number of bubbles in the molten metal bath; and/or can increase the transport velocity of the bubbles containing the dissolved gas to the surface of the molten metal bath. The ultrasonic device can create cavitation bubbles in close proximity to its tip. For example, in the case where the ultrasonic device has a tip with a diameter of about 2-5 cm, the cavitation bubbles may be at a distance of no more than about 15 cm, about 10 cm, about 5 cm, about 2 cm, or about 1 cm from the tip of the ultrasonic device before collapsing. If the purge gas is introduced too far from the tip of the ultrasonic device, it may not be able to diffuse into the cavitation bubbles. Therefore, in embodiments related to ultrasonic degassing and ultrasonic grain refinement, the purge gas is introduced into the molten metal bath at a distance of no more than about 25 cm or about 20 cm from the tip of the ultrasonic device and, for greater advantage, at a distance of no more than about 15 cm, no more than about 10 cm, no more than about 5 cm, no more than about 2 cm, or no more than about 1 cm from the tip of the ultrasonic device.

Ultrasonic devices according to embodiments of this invention may be in contact with a molten metal, such as aluminum or copper, for example, as described in U.S. Patent Publication No. 2009/0224443, the contents of which are incorporated herein by this reference in their entirety. In the case of an ultrasonic device designed to reduce the content of dissolved gas (e.g., hydrogen) in molten metal, niobium or an alloy thereof may be used as a protective barrier preventing the device from being exposed to the molten metal, or as one of the materials of the device that is directly exposed to the molten metal.

Embodiments of the present invention relating to ultrasonic degassing and ultrasonic grain refinement may provide systems and methods that provide an increase in the service life of components in direct contact with molten metals. For example, in order to reduce the deterioration of the properties of materials in contact with molten metals, embodiments of the invention may use niobium, which leads to a significant increase in the quality of finished products. In other words, embodiments of the invention can increase the service life or maintain the quality of materials or components in contact with molten metals by using niobium as a protective barrier. Niobium may have properties, such as a high melting point, that can help in developing the above-mentioned embodiments of the invention. In addition, niobium can also create a protective oxide barrier when exposed to temperatures of approximately 200 °C and above.

In addition, embodiments of the present invention relating to ultrasonic degassing and ultrasonic grain refinement may provide systems and methods that provide an increase in the service life of components that are in direct contact with molten metals or have an interface with them. Since niobium has low chemical reactivity with respect to certain molten metals, the use of niobium can prevent deterioration of the properties of the base material. Therefore, in embodiments of the invention relating to ultrasonic degassing and ultrasonic grain refinement, niobium can be used to reduce the deterioration of the properties of the base materials, which leads to a significant increase in the quality of finished products. Accordingly, when considering its use in working with molten metals, niobium can provide a combination of its high melting point and its low chemical reactivity with respect to these molten metals, for example, aluminum and / or copper.

In some embodiments, niobium or its alloy can be used in an ultrasonic device comprising an ultrasonic transducer and an elongated probe. The elongated probe can have a first end and a second end, wherein the first end can be attached to the ultrasonic transducer, and a tip can be located at the second end. According to this embodiment, the tip of the elongated probe can contain niobium (for example, niobium or its alloy). As discussed above, the ultrasonic device can be used in the ultrasonic degassing process. The ultrasonic transducer can generate ultrasonic waves, and the probe attached to the transducer can transmit ultrasonic waves into a container containing a bath of molten metal, such as aluminum, copper, zinc, steel, magnesium, etc., or mixtures and/or combinations thereof (for example, including various alloys of aluminum, copper, zinc, steel, magnesium, etc.).

In various embodiments of the invention, a combination of ultrasonic degassing and ultrasonic grain grinding is used. As described below, the use of a combination of ultrasonic degassing and ultrasonic grain grinding provides both individual advantages and combinations thereof. Without intending to impose limitations by the following description, this description allows one to understand the unique effects that arise when combining ultrasonic degassing and ultrasonic grain grinding, which leads to an overall improvement in the quality of the cast product, which would hardly be expected when using each of them separately. These effects were realized precisely by the inventors in the course of their development of this combined ultrasonic treatment.

In ultrasonic degassing, chlorine-containing chemicals (used when ultrasonic degassing is not used) are eliminated from the metal casting process. If chlorine, as a chemical, is present in the molten metal bath, it can react with other foreign chemical elements in the bath, such as alkali metals that may be present, to form strong chemical bonds. If alkali metals are present, stable salts are formed in the molten metal bath, which can lead to inclusions in the cast metal product, resulting in poor electrical conductivity and mechanical properties. If ultrasonic grain refinement is not used, chemical grain refiners such as titanium boride are used, but these materials usually contain alkali metals.

Accordingly, in the case of using ultrasonic degassing, eliminating the need to use chlorine as a chemical element in the processing, and using ultrasonic grain grinding, eliminating the need to use grain grinders (a source of alkali metals), the likelihood of the formation of stable salts and the resulting occurrence of inclusions in the cast metal product is significantly reduced. In addition, eliminating the presence of these foreign chemical elements as impurities increases the electrical conductivity of the cast metal product. Accordingly, in one embodiment of the invention, combining ultrasonic degassing and ultrasonic grain grinding means that the resulting cast metal product will have excellent mechanical properties and excellent electrical conductivity, since the need to use two main sources of impurities is eliminated without replacing one foreign impurity with another.

Another advantage provided by combining ultrasonic degassing and ultrasonic grain refinement is that both ultrasonic degassing and ultrasonic grain refinement effectively "stir" the molten metal bath, ensuring homogeneity of the material. When a metal alloy is melted and then cooled prior to crystallization, intermediate phases in the form of alloys may exist due to differences in melting temperatures at different percentage compositions of the alloy. In one embodiment of the invention, both ultrasonic degassing and ultrasonic grain refinement provide for the mixing and kneading of the intermediate phases back into the molten phase.

All these advantages result in a product with a fine grain structure, fewer impurities, fewer inclusions, improved electrical conductivity, improved ductility and higher tensile strength than would be expected using ultrasonic degassing alone or ultrasonic grain milling alone, or replacing them together or separately with conventional chlorine treatment or with chemical grain mills.

Demonstration process of ultrasonic grain grinding

The containing elements shown in Figs. 2, 3 and 3A were used, having a depth of 10 cm, a width of 8 cm and a shape of a rectangular tray or channel in the casting wheel 30. The thickness of the flexible metal strip was 6.35 mm. The width of the flexible metal strip was 8 cm. Steel 1010 was used for the strip. An ultrasonic frequency of 20 kHz was used, while a power of 120 watts (for each probe) was introduced into one or two transducers, the vibroprobes of which were in contact with water, which was a cooling medium. A part of the casting wheel made of copper alloy was used as a casting mold. Water as a cooling medium was supplied at a temperature close to room temperature and flowed through the channels 46 at a rate of about 15 liters per minute.

Molten aluminum was poured at a rate of 40 kg/min, producing a continuous aluminum casting with properties consistent with equiaxed grain structure without the addition of grain refiners. In fact, approximately 9 million pounds (4,082,331 kg) of aluminum rod were cast using this technology and drawn to final dimensions for wire and cable applications.

Hardware

According to one aspect of the present invention, it is possible to produce articles consisting of cast metal in the channel of the casting wheel or in the casting structures discussed above, which do not require the use of grain refiners, but which still have a submillimeter grain size. Accordingly, it is possible to produce a cast metal with a content of grain refiners of less than 5%, but at the same time a submillimeter grain size will still be ensured. It is possible to produce a cast metal with a content of grain refiners of less than 2%, but at the same time a submillimeter grain size will still be ensured. It is possible to produce a cast metal with a content of grain refiners of less than 1%, but at the same time a submillimeter grain size will still be ensured. In the preferred case, the refiners are contained at a level of less than 0.5%, less than 0.2% or less than 0.1%. It is possible to produce a cast metal that does not contain grain refiners, but at the same time a submillimeter grain size will still be ensured.

The cast metal may have different grain sizes at the submillimeter level, depending on a number of factors, including the components of the "pure" or alloyed metal used, the pouring rate, the pouring temperature, the cooling rate. The list of grain sizes available for the present invention includes the following sizes. In the case of aluminum and aluminum alloys, the grain size is in the range of 200-900 microns, 300-800 microns, 400-700 microns or 500-600 microns. In the case of copper and copper alloys, the grain size is in the range of 200-900 microns, 300-800 microns, 400-700 microns or 500-600 microns. In the case of gold, silver, tin or their alloys, the grain size is in the range of 200-900 microns, 300-800 microns, 400-700 microns or 500-600 microns. In the case of magnesium or magnesium alloys, the grain size is in the range of 200-900 microns, 300-800 microns, 400-700 microns or 500-600 microns. Although ranges are indicated, according to the invention, intermediate values are also possible. According to one aspect of the invention, grain refiners can be added in a small concentration (less than 5%) to further reduce the grain size to values from 100 to 500 microns. The cast metal can be aluminum, copper, magnesium, zinc, lead, gold, silver, tin, bronze, brass and their alloys.

Cast metal may be drawn or otherwise formed into rods, bars, sheet, wire, billets, or pellets.

Computerized control

The controller 500 shown in Figs. 1, 2, 3 and 4 may be implemented in practice using the computer system 1201 shown in Fig. 7. The computer system 1201 may be used as the controller 500 for controlling the above-mentioned casting systems or any other casting system or device that uses ultrasonic processing according to the present invention. Although the controller 500 is shown in Figs. 1, 2, 3 and 4 as a single unit, it may include separate and distinct processors that communicate with each other and/or are dedicated to a specific control function.

In particular, the controller 500 can be programmed using precisely those control algorithms that implement the functions illustrated in the block diagram in Fig. 8.

Fig. 8 shows a block diagram, the elements of which can be programmed or stored on a machine-readable information carrier or in one of the memory devices discussed below. The block diagram shown in Fig. 8 illustrates a method for creating places of the beginning of solidification in a metal product, corresponding to the present invention. At step 1802, the software block will control the operation of pouring molten metal into an element containing this metal. At step 1804, the software block will control the operation of cooling the element containing the molten metal, for example, by passing a liquid medium through a cooling channel in the immediate vicinity of this element. At step 1806, the software block will control the operation of introducing oscillation energy into the molten metal. At this step, the oscillation energy will be introduced at a frequency and power that make it possible to create places of the beginning of solidification in the molten metal, as discussed earlier.

Parameters such as the temperature of the molten metal, the pouring rate, the flow of the cooling medium through the cooling channels and the cooling of the casting mold, as well as parameters related to the control of the passage of the cast article through the apparatus, including the control of the power and frequency of the oscillating energy sources, will be programmed using standard programming languages (discussed below) to obtain special-purpose processors containing instructions that ensure the practical implementation of the method for creating crystallization initiation sites in a metal article that corresponds to the present invention.

More specifically, the computer system 1201 shown in Fig. 7 includes a bus 1202 or other information exchange means and a processor 1203 coupled to the bus 1202 and configured to process information. Computer system 1201 also includes a main memory 1204, such as a Random Access Memory (RAM) or other dynamic storage device (e.g., Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), and Synchronous Dynamic Random Access Memory (SDRAM)) coupled to bus 1202 and configured to store data and instructions executed by processor 1203. In addition, main memory 1204 may be used to store temporary variables or other intermediate data during execution of instructions by processor 1203. Computer system 1201 further includes a Read Only Memory (ROM) 1205 or other static storage device (e.g., Programmable Read Only Memory (PROM), Erasable Read Only Memory (EPROM), and Electrically Erasable Read Only Memory (EEPROM)) coupled to bus 1202 and configured to store static data and instructions for the 1203 processor.

The computer system 1201 also includes a disk controller 1206, connected to the bus 1202 and designed to control one or more storage devices designed to store data and instructions, such as a hard magnetic disk 1207, a removable storage media drive 1208 (for example, a floppy disk drive, a CD-ROM drive, a CD RW drive, a drive for multiple CDs, a magnetic tape drive and a removable magneto-optical disk drive). Storage devices can be added to the computer system 1201 using a suitable interface (for example, SCSI, IDE, E-IDE, DMA or UDMA).

Computer system 1201 may also include special-purpose logic devices (e.g., Application Specific Integrated Circuits (ASICs)) or configurable logic devices (e.g., Simple Programmable Logic Devices (SPLDs), Complex Programmable Logic Devices (CPLDs), and Field Programmable Gate Arrays (FPGAs)).

The computer system 1201 may also include a monitor controller 1209, connected to the bus 1202 and designed to control a monitor, such as a cathode ray tube (CRT) monitor or a liquid crystal display (LCD) monitor, designed to display information to a computer user. The computer system includes input devices, such as a keyboard and a pointing device, designed to interact with a computer user (for example, a user interacting with the controller 500) and input information to the processor 1203.

The computer system 1201 performs all or part of the processing steps according to the invention (for example, similar to those described in relation to the input of vibration energy into liquid metal in a state of maintaining a constant temperature) in response to the execution by the processor 1203 of one or more sequences of one or more instructions contained in a memory, for example, a main memory 1204. Such instructions can be read into the main memory 1204 from another machine-readable storage medium, for example, a hard disk 1207 or a removable storage drive 1208. One or more processors installed in a configuration that makes multiprocessing possible can also be used to execute the sequences of instructions contained in the main memory 1204. In alternative embodiments, a device with a circuit implementation of the algorithm can be used instead of or in combination with software instructions.

The computer system 1201 includes at least one computer-readable storage medium or memory for storing program instructions created in accordance with the principles of the invention, as well as data structures, tables, records or other data described herein. Examples of computer-readable storage media include compact discs, hard disks, floppy disks, tape, magneto-optical disks, programmable read-only memories (EPROM, EEPROM, Flash EPROM), DRAM, SRAM, SDRAM or any other magnetic storage medium, compact discs (e.g., CD-ROM) or any other optical storage medium, or other physical storage medium, carrier wave (described below), or any other storage medium that can be read by a computer.

The invention includes software intended to control the computer system 1201, to activate a device or devices that ensure the implementation of the invention in practice, and to enable the computer system 1201 to interact with a human user, which is stored in any of the computer-readable storage media or in a combination thereof. Such software may include, but is not limited to, device drivers, operating systems, development tools and application programs. Such computer-readable storage media further include computer program products corresponding to the invention, which are intended to perform all or part of the processing (if it is distributed) that is carried out when implementing the invention in practice.

Program code devices according to the invention may be interpreted or compiled and include, but are not limited to, scripts, interpreted programs, dynamically linked libraries (DLLs), Java classes, and fully compiled programs. In addition, the processing according to the invention may be distributed to improve performance and reliability and/or optimize costs.

The term "machine-readable storage medium" as used herein refers to any storage medium that participates in providing instructions to the processor 1203 for execution. Machine-readable storage medium may be of various types, including, but not limited to, non-volatile storage media, volatile storage media, and transmission media. Non-volatile storage media, for example, include optical disks, magnetic disks, and magneto-optical disks, such as the hard disk 1207 or the removable storage drive 120. Volatile storage media include dynamic memory, such as the main memory 1204. Transmission media include coaxial cables, copper wires, and optical fiber, including wires that form the bus 1202. Transmission media may also be in the form of sound or light waves, such as those generated by radio wave or infrared data transmission.

The computer system 1201 may also include a communication interface 1213 coupled to the bus 1202. The communication interface 1213 provides communication in a two-way data transfer mode with a network channel 1214, which is connected, for example, to a local area network (LAN) 1215 or another communication network 1216, such as the Internet. For example, the communication interface 1213 may be a network interface card designed to connect to any packet-switched LAN. As another example, the communication interface 1213 may be a card for an Asymmetric Digital Subscriber Line (ADSL), a card for an Integrated Services Digital Network (ISDN) or a modem, serving to provide a connection that ensures the exchange of data, with a communication line of the corresponding type. Wireless channels can also be implemented. In any such implementation, in practice, the communication interface 1213 sends and receives electrical, electromagnetic or optical signals carrying digital data streams representing information of various types.

The network channel 1214 typically provides data exchange with other devices intended for data processing over one or more networks. For example, the network channel 1214 may provide a connection to another computer via a local area network 1215 (e.g., LAN) or via equipment serviced by a service provider that provides communication services via a communication network 1216. In one embodiment, this capability allows the present invention to have a plurality of the above-described controllers 500 interconnected over a network for purposes such as automation of a plant as a whole or quality control. The local area network 1215 and the communication network 1216 use, for example, electrical, electromagnetic or optical signals carrying digital data streams and an appropriate physical layer (e.g., CAT5 cable, coaxial cable, optical fiber, etc.). Signals transmitted in various networks, in network channel 1214 and via communication interface 1213, which carry digital data to and from computer system 1201, can be implemented as baseband signals or carrier wave-based signals. Baseband signals transport digital data as unmodulated electrical pulses containing information about a stream of digital data bits, where the term "bits" should be perceived in a broad sense as a symbol, where each symbol contains at least one bit of information. Digital data can also be used to modulate a carrier wave, as an example can be given signals with amplitude, phase and/or frequency manipulation, which are propagated through a conductive medium or transmitted as electromagnetic waves through a propagation medium. Thus, digital data can be sent as an unmodulated signal in the original frequency range over a "wired" communication channel and/or sent in a band of predetermined frequencies, different from the original frequency band, as a result of modulating a carrier wave. The computer system 1201 can transmit and receive data, including program code, via the network(s) 1215 and 1216, the network channel 1214 and the communication interface 1213. In addition, the network channel 1214 can provide a connection via LAN 1215 with a mobile device 1217, such as a Personal Digital Assistant (PDA), a laptop or a cell phone.

More specifically, in one embodiment of the invention, a continuous casting and rolling system (CCRS) is provided that allows producing pure aluminum rod of quality suitable for use in electrical conductors and coils containing alloyed aluminum rod of quality suitable for use in conductors directly from molten metal in a continuous mode. The CCRS system may use one or more computer systems 1201 (described above) to implement control, monitoring and data storage.

In one embodiment of the invention, to ensure high quality aluminum rod output, the rolling mill (i.e., CCRS) is monitored and/or controlled using a Supervisory Control and Data Acquisition (SCADA) system. Additional variables and parameters of this system can be displayed, graphed, stored, and analyzed for quality control.

In one embodiment of the invention, the data acquisition system includes one or more post-manufacturing product testing processes, as described below.

Eddy current flaw detectors can be used to continuously monitor the surface quality of aluminum rod. Inclusions can be detected if they are near the surface of the rod, since an inclusion in the matrix appears as an isolated defect. During the casting and rolling of aluminum rod, defects present in the finished product can occur at any stage of the process. Incorrect chemistry of the melt and / or excessive amounts of hydrogen in the metal can cause defects to occur during rolling. The use of an eddy current system is a non-destructive testing method, and the control system for the CCRS system can alert the operator (operators) if any of the above defects occur. The eddy current system can detect surface defects and classify defects into small, medium and large. The eddy current measurement results can be recorded in the SCADA system and can be related to the aluminum (or other metal being processed) lot and its production time.

After the rod is wound into a coil at the end of the process, the overall mechanical and electrical properties of the cast aluminum can be measured and recorded in the SCADA system. The following parameters are used in checking the quality of the product: tensile strength, elongation, and conductivity. Tensile strength is a measure of the strength of the materials and is the maximum force that the material can withstand when stretched before breaking. Elongation is a measure of the ductility of the material. Conductivity measurements are usually given as a percentage of the International Annealed Copper Standard (IACS). These product quality parameters can be recorded in the SCADA system and related to the aluminum batch and its production time.

In addition to eddy current data, surface analysis can be performed using torsion testing. Cast aluminum rod is subjected to a controlled torsion test. In the twisted rod, defects associated with improper solidification, inclusions, and longitudinal defects that occur during rolling are amplified and revealed. Generally speaking, these defects appear as a scar parallel to the rolling direction. A series of parallel lines after twisting the rod clockwise and counterclockwise indicates a homogeneous sample, while inhomogeneities that occur during casting will result in wavy lines. The torsion test results can be recorded in a SCADA system and related to the aluminum batch and its production time.

Sample analysis

The samples discussed below were produced using the CCR system described above. The casting and rolling process that produced these samples began with a continuous stream of molten aluminum being transported from the melting and reheating furnace system through a refractory trough system to either a chemical grain refiner on the same line or the ultrasonic grain refiner discussed above. In addition, the CCR system included the ultrasonic degasser system discussed above, which uses ultrasound waves and a purge gas to remove dissolved hydrogen or other gases from the molten aluminum. From the degasser, the molten metal passed to a porous ceramic molten metal filter, which further reduced the inclusion content of the molten metal. The trough system then transported the molten aluminum to the pouring device. From the casting device, molten aluminum was poured into a mold formed by a circumferential groove in a copper casting ring and a steel strip as discussed above. To produce a solid cast rod, the molten aluminum was cooled by water supplied by spray nozzles from multi-zone water collectors equipped with magnetic flow meters for important zones. A continuous aluminum cast rod exited the casting ring onto a rod conveyor leading to the rolling mill.

The rolling mill included individually driven stands that reduced the diameter of the rod. The rod was then sent to a drawing mill where it was drawn to a predetermined diameter and then wound into a coil. After the rod was wound into a coil at the end of the process, the general mechanical and electrical properties of the cast aluminum were measured. The following parameters are used in quality testing: tensile strength, elongation, and conductivity. Tensile strength is a measure of the strength of materials and is the maximum force that a material can withstand when stretched before breaking. Elongation is a measure of the ductility of the material. Conductivity results are usually given as a percentage of the International Annealed Copper Standard (IACS).

1) Tensile strength is a measure of the strength of materials and represents the maximum force that a material can withstand when stretched before failure. Tensile strength and elongation measurements were performed on the same specimen. A specimen with a 10" (254 mm) gauge length was selected for measuring tensile strength and elongation. The rod specimen was mounted in a tensile testing machine. The clamps were placed at the 10" (254 mm) length marks. Tensile strength = Force at Break (lbs) / Cross-sectional Area ( πr ² ), where r (inches) is the radius of the rod.

2) Relative elongation in percent = (( L ₁ - L ₂ )/ L ₁ × 100. L ₁ is the initial, basic length of the material and L ₂ is the final length obtained by joining two parts of the destroyed sample after a tensile test and measuring the resulting length. Generally speaking, a sample made of a more plastic material will exhibit a greater narrowing under tension.

3) Conductivity: Conductivity measurements are generally reported as a percentage of the International Annealed Copper Standard (IACS). Conductivity is measured using a Thomson bridge, details of which are given in ASTM B193-02. The IACS is a measure of the electrical conductivity of metals and alloys compared to a standard annealed copper conductor; an IACS value of 100% represents a conductivity of 5.80 x 10 ⁷ S (Siemens) per meter (58.0 MS/m) at 20°C.

The continuous rod manufacturing process described above is not only used to produce aluminum conductors with grades suitable for use in electric cables, but by using ultrasonic grain refinement and ultrasonic degassing, it can also be used to produce aluminum alloys used in mechanical engineering. To study the ultrasonic grain refinement process, cast rod samples were obtained and etched.

To determine the properties of the bars, a comparative analysis was conducted between the bars cast using the ultrasonic grain grinding process and the bars cast using conventional TIBOR grain grinders. Table 1 shows the results for the bars produced by processing using the ultrasonic grinding device and the results for the bars produced by processing using TIBOR grain grinders for comparison.

Table 1

Quality Testing: Comparison of Ultrasonic Grain Grinding with Chemical Grain Grinding ¹

Ultrasonic grain grinding process Tests carried out Data ranges Average value ^d Standard deviation Tensile strength ^a , kpsi 16.6-18.6 17.76 0.81 Relative elongation ^b 5-8 6 1.36 Conductivity ^c 61.7-61.9 61.76 0.09 Adding a chemical grain grinder (TiBor) Tests carried out Data ranges Average value ^d Standard deviation Tensile strength ^a , kpsi 18-18.7 18.29 0.29 Relative elongation ^b 5-7 6.23 0.53 Conductivity ^c 61.5-61.7 61,67 0.08

¹ a: 1000 psi (× 6.895 MPa); b: as a percentage; c: given as a percentage of IACS d: average of 13 coils

In the twisted bar, the defects associated with inadequate crystallization and inclusions and longitudinal defects that arose during the rolling process were amplified and revealed. Generally speaking, these defects appear as a scar parallel to the rolling direction. A series of parallel lines after twisting the bar clockwise and counterclockwise indicates the homogeneity of the sample, while inhomogeneities that arise during casting will lead to the appearance of wavy lines.

The data shown in Table 2 below indicate that very few defects were produced using ultrasound. Although no definitive conclusions can be drawn from this data set alone, it appears that the number of surface defects detected by the eddy current inspection device was lower for the ultrasonically processed material.

Table 2

Defect Analysis: Comparison of Ultrasonic Grain Grinding with Chemical Grain Grinding

Ultrasonic grain grinding process Size of the defect Ranges Average value Standard deviation Big 0-0 0 0 Average 0-3 0.23 0.80 Small 0-6 2.15 1.87 Adding a chemical grain grinder (TiBor) Size of the defect Ranges Average value Standard deviation Big 1-8 1.46 2.44 Average 0-17 3.62 4.43 Small 0-22 6.92 6.75

The results of the twisting test showed that the surface quality of the rod produced using ultrasonic grain refiner was as good as that of the rod produced using chemical grain refiner. After installing the ultrasonic grain treatment device on the continuous rod (CR) production line, the use of chemical refiner was reduced to zero, but high-quality cast rod could still be obtained. The hot rolled rod was then drawn to obtain wires with dimensions in the range of 0.1052" (2.67 mm) - 0.1878" (4.77 mm). The wires were then processed to obtain overhead transmission cables.

There are two separate types of conductor that the products could be used for: Aluminum Conductor Steel Supported (ACSS) and Aluminum Conductor Steel Reinforced (ACSR). The only difference between the two conductor manufacturing processes is that the ACSS aluminum conductor is annealed after stranding.

Fig. 10 is a flow chart of the manufacturing process of ACSR conductor. This drawing shows the conversion of pure molten aluminum into aluminum wire to be used in ACSR conductor. The first step in the conversion process is to produce an aluminum rod from molten aluminum. The next step is to draw the rod through several drawing dies and, depending on the final diameter, the drawing may be done in several steps. After the final diameter is obtained by drawing the rod, the wire is wound onto spools to obtain weights in the range of 200 pounds (90.72 kg) to 500 pounds (226.8 kg). The wire from these individual spools is wound around a stranded steel cable to produce an ACSR cable containing several individual stranded aluminum wires. The number of stranded wires and the diameter of each stranded wire will depend on the customer's requirements.

Figure 11 is a flow chart of the manufacturing process of ACSS conductor. This drawing shows the conversion of pure molten aluminum into aluminum wire to be used in ACSS conductor. The first step in the conversion process is to produce an aluminum rod from molten aluminum. The next step is to draw the rod through several drawing dies and, depending on the final diameter, the drawing may be done in several steps. After the rod has been drawn to the final diameter, the wire is wound onto spools to obtain weights in the range of 200 pounds (90.72 kg) to 500 pounds (226.8 kg). The wire from these individual spools is wound around a stranded steel cable to produce an ACSS cable containing several individual stranded aluminum wires. The number of stranded wires and the diameter of each stranded wire will depend on the customer's requirements. The only difference between ACSR and ACSS cables is that after the aluminum is wrapped around the steel cable, the entire cable is heat treated in furnaces to give the aluminum a fully annealed condition. It is important to note that in the case of ACSR cable, the strength of the cable comes from the combination of the strength of the aluminum and steel wires, while in ACSS cable, most of the strength comes from the steel in the center.

Figure 12 is a flow chart of the process for producing aluminum strip where the strip is ultimately converted into a sheathed cable. This figure shows that the first step in the conversion process is to produce an aluminum rod from molten aluminum. The rod is then rolled through a series of dies to form a strip typically having a width of approximately 0.375" (9.53 mm) and a thickness of approximately 0.015" (0.38 mm) - 0.018" (0.46 mm). The rolled strip is formed into toroidal rolls weighing approximately 600 pounds (272.2 kg). It is important to note that other widths and thicknesses can also be produced using rolling, but a width of 0.375" (9.53 mm) and a thickness of 0.015" (0.38 mm) - 0.018" (0.46 mm) are the most common. These rolls are then heat treated in furnaces to obtain an intermediate annealed condition. In this condition, the aluminum is neither fully hard nor fully annealed. The strip is then used as a protective jacket, assembled as armor from interconnected metal tapes (strips), in which one or more insulated conductors of electric current are enclosed.

The following comparative analysis for these processes was performed for drawn aluminum wire that was produced using the ultrasonic grain refinement process and aluminum wire that was produced using conventional TIBOR grain refiners. The drawn samples met all specifications outlined in the ASTM 1350 Electrical Wire Standards.

Properties of a conventional rod including chemical grain crushers TIBOR

Rod 1350 ^* EC, diameter 0.375" (9.53 mm) Tensile strength ^A , kpsi Tensile strength ^B , MPa Relative elongation ^C IACS ^D , % Average value 14.41 99,2849 20.2 61.98 Standard deviation 0.364554523 2,511780661 1,805547009 0.09798 Min 13.6 93,704 17 61.8 Max 14.9 102,661 25 62.1 Rod 8176 ^* EEE, diameter 0.375" (9.53 mm) Tensile strength ^A , kpsi Tensile strength ^B , MPa Relative elongation ^C IACS ^D , % Average value 17,875 123,15875 17.05 59.79 Standard deviation 0.719635324 4,958287385 0,217944947 0.099499 Min 16.2 111,618 17 59.7 Max 18.9 130,221 18 59.9 Rod 5154 ^* , diameter 0.375" (9.53 mm) Tensile strength ^A , kpsi Tensile strength ^B , MPa Relative elongation ^C IACS ^D , % Average value 32,915 226,78435 18.75 - Standard deviation 0.358154994 2,467687911 0.698212002 - Min 32.1 221,169 18 - Max 33.5 230,815 20 - Rod 5356 ^* , diameter 0.375" (9.53 mm) Tensile strength ^A , kpsi Tensile strength ^B , MPa Relative elongation ^C IACS ^D , % Average value 43.97 302,9533 18.5 - Standard deviation 0.613269924 4,225429778 0.5 - Min 43.4 299,026 18 - Max 45.2 311,428 19 -

Properties of ultrasonic treated rod

Rod 1350 ^* EC, diameter 0.375" (9.53 mm) Tensile strength ^A , kpsi Tensile strength ^B , MPa Relative elongation ^C IACS ^D , % Average value 13.93 95,9777 21.1 62.17 Standard deviation 0.401372645 2,765457523 2,3 0,130767 Min 13.2 90,948 17 62 Max 14.5 99,905 25 62.3 Rod 8176 ^* EEE, diameter 0.375" (9.53 mm) Tensile strength ^A , kpsi Tensile strength ^B , MPa Relative elongation ^C IACS ^D , % Average value 16.63 114,5807 19.35 60.86 Standard deviation 0.815536633 5,619047402 1,38834434 0.04899 Min 15.1 104,039 17 60.8 Max 18.5 127,465 23 60.9 Rod 5154 ^* , diameter 0.375" (9.53 mm) Tensile strength ^A , kpsi Tensile strength ^B , MPa Relative elongation ^C IACS ^D , % Average value 33.97 234,0533 18.9 - Standard deviation 0.491019348 3,383123307 0.99498744 - Min 33.2 228,748 18 - Max 34.7 239,083 22 - Rod 5356 ^* , diameter 0.375" (9.53 mm) Tensile strength ^A , kpsi Tensile strength ^B , MPa Relative elongation ^C IACS ^D , % Average value 41.5 285,935 19.2 - Standard deviation 0.761577311 5,24726767 0.87177979 - Min 40.1 276,289 18 - Max 42.6 293,514 20 -

Conditions for processing rods with ultrasonic treatment

Alloy designation Casting speed Degree of ultrasonic degassing Frequency in ultrasonic degassing Degree of ultrasonic grain grinding Frequency in ultrasonic grain grinding 1350 (EU) 15 tons per hour 60% 20 kHz 80% 20 kHz 8176 (EEE) 15 tons per hour 60% 20 kHz 80% 20 kHz 5154 4 tons per hour 60% 20 kHz 80% 20 kHz 5356 4 tons per hour 60% 20 kHz 80% 20 kHz

^* Alloy designations are given in accordance with the specifications of the Aluminum Manufacturers Association

^** ACSS cable

^*** ACSR wire

A - 1000 psi

B - Tensile strength in MPa

C - Relative elongation in percent

D - International Standard for Annealed Copper

^* Length is in inches

Fig. 15 shows microphotographs of aluminum alloy 1350 EC for comparison of grain structure in castings in the absence of chemical grain grinders, in the presence of chemical grain grinders, and in the presence of only ultrasonic grain grinding;

Fig. 16 shows a table for comparing a conventional 1350 EC aluminum alloy rod (with chemical grain grinders) with a 1350 EC aluminum alloy rod (with ultrasonic grain grinding);

Fig. 17 shows a table comparing a conventional ACSR (chemical grain crusher) aluminum wire having a diameter of 0.130" (3.3 mm) with an ACSR (ultrasonic grain crusher) aluminum wire having a diameter of 0.130" (3.3 mm);

Fig. 18 shows a table for comparing a conventional rod made of aluminum alloy 8176 EEE (with chemical grain grinders) with a rod made of aluminum alloy 8176 EEE (with ultrasonic grain grinding);

Fig. 19 shows a table comparing a conventional 5154 aluminum alloy rod (with chemical grain grinders) with a 5154 aluminum alloy rod (with ultrasonic grain grinding);

Fig. 20 shows a table for comparing a conventional 5154 aluminum alloy strip (with chemical grain grinders) with a 5154 aluminum alloy strip (with ultrasonic grain grinding);

Fig. 21 shows a table indicating the properties of a rod made of aluminum alloy 5356 (with ultrasonic grain refinement).

General provisions of the invention

The following provisions of the invention indicate one or more characteristics of the present invention and do not limit the scope of the present invention.

Provision 1. A device for processing molten metal, intended for use on a casting wheel of a casting machine, which comprises: an assembly mounted on the casting wheel (or associated with it), which includes at least one source of vibration energy, introducing (for example, which is designed to introduce) vibration energy (for example, ultrasonic energy, energy created mechanically, and/or sound energy) into molten metal poured onto the casting wheel, during the cooling of this metal located on the casting wheel, a support device holding said at least one source of vibration energy, and, as an optional option, a guide device positioning the assembly when moving the casting wheel.

Provision 2. A device according to Provision 1, wherein the supporting device comprises a housing containing a cooling channel that provides for the transport of a cooling medium. Provision 3. A device according to Provision 2, wherein said cooling medium is located in the cooling channel, containing at least one of the following: water, gas, liquid metal and engine oil.

Provision 4. A device according to Provisions 1, 2, 3 or 4, wherein said at least one source of vibration energy comprises at least one ultrasonic transducer, at least one mechanically driven vibrator or a combination thereof.

Provision 5. A device in accordance with Provision 4, in which the ultrasonic transducer (e.g., a piezoelectric element) is designed to generate oscillation energy in the frequency range of up to 400 kHz, or in which the ultrasonic transducer (e.g., a magnetostrictive element) is designed to generate oscillation energy in the frequency range of 20-200 kHz.

Provision 6. A device according to Provision 1, 2 or 3, wherein the mechanically driven vibrator is a plurality of mechanically driven vibrators.

Provision 7. A device in accordance with Provision 4, in which the vibrator with a mechanical drive is designed to generate oscillation energy in the frequency range of up to 10 kHz, or in which the vibrator with a mechanical drive is designed to generate oscillation energy in the range of 8000-15000 oscillations per minute.

Provision 8a. The apparatus of Provision 1, wherein the casting wheel includes a strip serving as a boundary for the molten metal contained in the channel of the wheel.

Provision 8b. An apparatus according to any of Provisions 1-7, wherein the unit is located above the casting wheel and has passages in the housing for the passage of a strip therethrough, which serves as a boundary for molten metal located in the channel of that wheel.

Position 9. The device according to Position 8, in which the strip is positioned in a direction along the body to allow the cooling medium to flow from the cooling channel along the side of this strip opposite to the side on which the molten metal is located.

Provision 10. A device according to any of Provisions 1-9, wherein the support device comprises at least one of the following: niobium, a niobium alloy, titanium, a titanium alloy, tantalum, a tantalum alloy, copper, a copper alloy, rhenium, a rhenium alloy, steel, molybdenum, a molybdenum alloy, stainless steel, ceramic, composite, polymer or metal.

Provision 11. A device according to Provision 10, wherein the ceramic comprises silicon nitride ceramic.

Provision 12. A device according to Provision 11, wherein the silicon nitride ceramic comprises SIALON.

Provision 13. An appliance in accordance with any of Provisions 1 to 12, wherein the body comprises a fire-resistant material.

Provision 14. An apparatus according to Provision 13, wherein the refractory material comprises at least one of the following: copper, niobium, niobium and molybdenum, tantalum, tungsten, rhenium and alloys thereof.

Provision 15. An apparatus according to Provision 14 wherein the refractory material contains one or more of the following: silicon, oxygen or nitrogen.

Provision 16. A device according to any of Provisions 1-15, wherein several of said vibration energy sources, comprising at least one, are in contact with the cooling medium, for example, are in contact with the cooling medium flowing through the support device or the guide device. Provision 17. A device according to Provision 16, wherein said at least one vibration energy source comprises at least one vibration probe installed in a cooling channel present in the support device. Provision 18. A device according to any of Provisions 1-3 and 6-15, wherein said at least one vibration energy source comprises at least one vibration probe in contact with the support device. Provision 19. A device according to any of Provisions 1-3 and 6-15, wherein said at least one vibration energy source comprises at least one vibration probe in contact with the strip at the base of the support device. Provision 20. A device according to any of Provisions 1-19, wherein said vibration energy sources, numbering at least one, comprise a plurality of vibration energy sources mounted in the support device in different positions.

Provision 21. A device in accordance with any of Provisions 1 to 20, wherein the guide device is located on a strip located on the rim of the casting wheel.

Provision 22. A method for manufacturing a metal product comprising the following stages:

- place the molten metal into the containing element of the casting installation;

- cool the molten metal contained in the containing element; and

- introduce vibration energy into the molten metal located in the containing element during the said cooling.

Provision 23. The method according to Provision 22, wherein placing the molten metal comprises pouring the molten metal into a channel in a casting wheel.

Provision 24. The method according to Provisions 22 or 23, wherein the input of vibration energy comprises supplying this energy from an ultrasonic transducer and/or a magnetostrictive transducer. Provision 25. The method according to Provision 24, wherein the supply of vibration energy comprises generating vibration energy in the frequency range of 5-40 kHz. Provision 26. The method according to Provisions 22 or 23, wherein the input of vibration energy comprises supplying this energy from a vibrator with a mechanical drive. Provision 27. The method according to Provision 26, wherein the supply of vibration energy comprises generating vibration energy in the frequency range of 8000-15000 vibrations per minute or up to 10 kHz.

Provision 28. A method according to any of Provisions 22-27, wherein cooling comprises cooling the molten metal by exposing the molten metal retaining member to at least one of water, gas, liquid metal, and engine oil.

Provision 29. A method according to any of Provisions 22-28, wherein placing molten metal comprises feeding molten metal into a casting mould. Provision 30. A method according to any of Provisions 22-29, wherein placing molten metal comprises feeding molten metal into a continuous casting mould. Provision 31. A method according to any of Provisions 22-30, wherein placing molten metal comprises feeding molten metal into a horizontal or vertical casting mould.

Provision 32. A casting plant comprising a casting mould adapted to cool molten metal and a device for handling molten metal in accordance with any of Provisions 1 to 21. Provision 33. A casting plant according to Provision 32, in which the casting mould comprises a continuous casting mould. Provision 34. A casting plant according to Provisions 32 or 33, in which the casting mould comprises a horizontal or vertical casting mould.

Provision 35. A casting installation comprising: an element containing molten metal, which is designed with the possibility of cooling this metal; and a source of oscillation energy attached to the said containing element and designed with the possibility of introducing oscillation energy with a frequency of up to 400 kHz into the molten metal.

Provision 36. A casting installation comprising: an element containing molten metal, which is designed with the possibility of cooling this metal; and a source of oscillation energy with a mechanical drive, attached to the said containing element and designed with the possibility of introducing oscillation energy into the molten metal with a frequency in the range of up to 10 kHz (including ranges of 0-15,000 oscillations per minute and 8,000-15,000 oscillations per minute).

Provision 37. A system for manufacturing a metal article comprising: means for pouring molten metal into an element containing the molten metal; means for cooling said containing element; means for introducing into the molten metal oscillation energy with a frequency of up to 400 kHz (including ranges of 0-15,000 oscillations per minute, 8,000-15,000 oscillations per minute, up to 10 kHz, 15-40 kHz or 20-200 kHz); and a controller configured to receive data signals and output control signals and programmed using control algorithms that ensure the execution of any of the steps specified in Provisions 22-31.

Provision 38. A system for manufacturing a metal article comprising: a device for processing molten metal in accordance with any of Provisions 1-21; and a controller configured to receive data signals and output control signals and programmed using control algorithms that ensure the performance of any of the steps specified in Provisions 22-31.

Provision 39. A system for producing a metal article comprising: an assembly associated with a casting wheel which includes a housing which retains a cooling medium in such a way as to make it possible for molten metal poured onto the casting wheel to be cooled by this cooling medium, and a device which positions this assembly when the casting wheel is moved.

Regulation 40. A system in accordance with Regulation 38, including any of the elements specified in Regulations 2, 3, 8-15 and 21.

Provision 41. A device for processing molten metal intended for use in a casting installation, which comprises: at least one source of vibration energy introducing vibration energy into molten metal poured onto a casting wheel during cooling of this metal located on the casting wheel; and a support device holding the source of vibration energy.

Regulation 42. A device in accordance with Regulation 41 incorporating any of the elements specified in Regulations 4 to 15.

Provision 43. A device for handling molten metal, intended for use on a casting wheel of a casting machine, which comprises: an assembly associated with the casting wheel, which includes 1) at least one source of vibration energy, introducing vibration energy into molten metal poured onto the casting wheel, during the cooling of this metal located on the casting wheel, 2) a support device holding said at least one source of vibration energy, and, as an optional option, 3) a guide device positioning the assembly when moving the casting wheel.

Provision 44. The device according to Provision 43, wherein said at least one source of vibration energy introduces vibration energy directly into the molten metal poured onto the casting wheel.

Provision 45. The device according to Provision 43, wherein said at least one source of vibration energy indirectly introduces vibration energy into the molten metal poured onto the casting wheel.

Provision 46. A device for treating molten metal intended for use in a casting installation, which comprises: at least one source of vibration energy introducing vibration energy by means of a probe introduced into the molten metal poured onto a casting wheel during the cooling of this metal located on the casting wheel; and a support device holding the source of vibration energy, wherein the vibration energy reduces segregation in the molten metal during its crystallization.

Regulation 47. A device in accordance with Regulation 46 incorporating any of the elements specified in Regulations 2 to 21.

Provision 48. A device for treating molten metal, intended for use in a casting installation, which comprises: at least one source of vibration energy introducing sound energy into molten metal poured onto a casting wheel during cooling of this metal located on the casting wheel; and a support device holding the source of vibration energy.

Provision 49. A device according to Provision 48, wherein said at least one source of vibration energy comprises a sound amplifier.

Provision 50. An apparatus according to Provision 49, in which the sound amplifier introduces vibration energy into the molten metal through a gaseous medium.

Provision 51. An apparatus according to Provision 49, in which the sound amplifier introduces vibration energy through a gaseous medium into a support member holding the molten metal.

Provision 52. A method of grain refinement comprising the following steps: introducing vibration energy into molten metal during its cooling; and breaking apart dendrites that have arisen in the molten metal to create crystallization centers in it.

Provision 53. The method according to Provision 52, wherein the vibration energy comprises at least one of the following: ultrasonic vibrations, mechanically generated vibrations, and sound vibrations.

Provision 54. The method according to Provision 52, wherein foreign impurities are not a source of crystallization centers in the molten metal.

Provision 55. The method of Provision 52, wherein a portion of the molten metal is supercooled to create dendrites.

Provision 56. A device for processing molten metal, comprising:

- source of molten metal;

- an ultrasonic degasser, including an ultrasonic probe inserted into the molten metal;

- a casting mold designed to receive molten metal;

- a unit installed on a casting mold, which includes:

- at least one source of vibration energy that introduces vibration energy into the molten metal poured into the casting mold during the cooling of this metal located in the casting mold, and

- a support device holding said at least one source of vibration energy.

Provision 57. A device according to Provision 56, wherein the casting mould comprises part of a casting wheel of a casting machine.

Provision 58. A device according to Provision 56, wherein the supporting device comprises a housing containing a cooling channel providing for the transport of a cooling medium.

Provision 59. A device according to Provision 58, wherein said cooling medium is located in the cooling channel, comprising at least one of the following: water, gas, liquid metal and engine oil.

Provision 60. A device according to Provision 56, wherein said at least one source of vibration energy comprises an ultrasonic transducer.

Provision 61. A device according to Provision 56, wherein said at least one source of vibration energy comprises a vibrator with a mechanical drive.

Provision 62. A device in accordance with Provision 61, in which the mechanically driven vibrator is designed to generate oscillation energy in the frequency range up to 10 kHz.

Provision 63. A device according to Provision 56, wherein the casting mould includes a strip serving as a boundary for the molten metal contained in the channel of the casting wheel.

Provision 64. A device according to Provision 63, in which the unit is located above the casting wheel and has passages in the body for the passage of a strip through which it serves as a boundary for the molten metal contained in the channel of that wheel.

Provision 65. The device according to Provision 64, in which the strip is positioned in a direction along the body to allow the cooling medium to flow from the cooling channel along the side of this strip opposite to the side on which the molten metal is located.

Provision 66. The device according to Provision 56, wherein the support device comprises at least one of the following: niobium, a niobium alloy, titanium, a titanium alloy, tantalum, a tantalum alloy, copper, a copper alloy, rhenium, a rhenium alloy, steel, molybdenum, a molybdenum alloy, stainless steel, ceramic, composite, polymer or metal.

Provision 67. A device according to Provision 66, wherein the ceramic comprises silicon nitride ceramic.

Provision 68. A device according to Provision 67, wherein the silicon nitride ceramic comprises SIALON.

Regulation 69. An appliance in accordance with Regulation 64 wherein the body contains a fire-resistant material.

Provision 70. An apparatus according to Provision 69, wherein the refractory material comprises at least one of the following: copper, niobium, niobium and molybdenum, tantalum, tungsten, rhenium and alloys thereof.

Regulation 71. An apparatus in accordance with Regulation 69 in which the refractory material contains one or more of the following: silicon, oxygen or nitrogen.

Provision 72. A device according to Provision 56, wherein of said vibration energy sources, comprising at least one, several vibration energy sources are in contact with the cooling medium.

Provision 73. The device according to Provision 72, wherein said at least one source of vibration energy comprises at least one vibration probe installed in a cooling channel present in the supporting device.

Provision 74. The device according to Provision 56, wherein said at least one source of vibration energy comprises at least one vibration probe in contact with the support device.

Provision 75. A device according to Provision 56, wherein said at least one source of vibration energy comprises at least one vibration probe directly in contact with the strip at the base of the support device.

Provision 76. The device according to Provision 56, wherein said vibration energy sources, numbering at least one, comprise a plurality of vibration energy sources installed in the support device in different positions.

Provision 77. The device in accordance with Provision 57, further comprising a guide device that positions the unit when the casting wheel is moved.

Provision 78. A device according to Provision 72, wherein the guide device is located on a strip located on the rim of the casting wheel.

Provision 79. A device in accordance with Provision 56, in which the ultrasonic degasser comprises:

- an elongated probe, the first end of which is attached to an ultrasonic transducer, and at the second end of which is the tip of this probe, and

- a means for supplying a purge gas comprising an inlet for the purge gas and an outlet for the purge gas, wherein the outlet for the purge gas is located on the tip of the extended probe and is intended for introducing the purge gas into the molten metal.

Statement 80. A device according to Statement 56, wherein the extended probe comprises ceramic.

Provision 81. A metal article comprising cast metal having a sub-millimeter grain size, including less than 0.5% grain refiners and having at least one of the following properties:

- relative elongation in the range of 10-30% when exposed to a tensile force of 100 psi (689.5 kPa),

- tensile strength in the range of 50-300 MPa; or

- electrical conductivity in the range of 45-75% of IAC, which is the electrical conductivity specified as a percentage relative to IAC - the electrical conductivity of a standard annealed copper conductor.

Provision 82. An article in accordance with Provision 81 in which the cast metal comprises less than 0.2% grain refiners.

Provision 83. An article in accordance with Provision 81 in which the cast metal comprises less than 0.1% grain refiners.

Provision 84. An article in accordance with Provision 81 in which the cast metal does not include grain grinders.

Provision 85. An article in accordance with Provision 81, in which the cast metal comprises at least one of the following: aluminium, copper, magnesium, zinc, lead, gold, silver, tin, bronze, brass and their alloys.

Provision 86. An article according to Provision 81 in which the cast metal is formed to form at least one of the following: rods, bars, sheets, wire, billets or pellets.

Provision 87. An article in accordance with Provision 81 having an elongation in the range of 15-25% or a tensile strength in the range of 100-200 MPa or an electrical conductivity in the range of 50-70% IAC.

Provision 88. An article in accordance with Provision 81 having an elongation in the range of 17-20% or a tensile strength in the range of 150-175 MPa or an electrical conductivity in the range of 55-65% IAC.

Provision 89. An article in accordance with Provision 81 having an elongation in the range of 18-19% or a tensile strength in the range of 160-165 MPa or an electrical conductivity in the range of 60-62% IAC.

Provision 90. An article in accordance with any of Provisions 81, 87, 88 and 89 in which the cast metal comprises aluminium or an aluminium alloy.

Provision 91. An article in accordance with Provision 90 in which the aluminium or aluminium alloy constitutes a stranded wire with steel reinforcement.

Provision 92. An article in accordance with Provision 90 in which the aluminium or aluminium alloy is a stranded conductor with a steel support.

Provision 92. A metal product manufactured using one or more of the steps specified in Provisions 52 to 55 and containing cast metal.

Provision 93. An article in accordance with Provision 92 in which the cast metal has a sub-millimeter grain size and includes less than 0.5% grain refiners.

Provision 94. An article in accordance with Provision 92, having at least one of the following properties:

- relative elongation in the range of 10-30% when exposed to a tensile force of 100 psi (689.5 kPa),

- tensile strength in the range of 50-300 MPa; or

- electrical conductivity in the range of 45-75% of IAC, which is the electrical conductivity specified as a percentage relative to IAC - the electrical conductivity of a standard annealed copper conductor.

Provision 95. An article in accordance with Provision 92 in which the cast metal comprises less than 0.2% grain refiners.

Provision 96. An article in accordance with Provision 92 in which the cast metal comprises less than 0.1% grain refiners.

Provision 97. An article in accordance with Provision 92 in which the cast metal does not include grain grinders.

Provision 98. An article in accordance with Provision 92, wherein the cast metal comprises at least one of the following: aluminium, copper, magnesium, zinc, lead, gold, silver, tin, bronze, brass and their alloys.

Provision 99. An article according to Provision 92 in which the cast metal is formed to form at least one of the following: rods, bars, sheets, wire, billets or pellets.

Provision 100. An article in accordance with Provision 92 having an elongation in the range of 15-25% or a tensile strength in the range of 100-200 MPa or an electrical conductivity in the range of 50-70% IAC.

Provision 101. An article in accordance with Provision 92 having an elongation in the range of 17-20% or a tensile strength in the range of 150-175 MPa or an electrical conductivity in the range of 55-65% IAC.

Provision 102. An article in accordance with Provision 92 having an elongation in the range of 18-19% or a tensile strength in the range of 160-165 MPa or an electrical conductivity in the range of 60-62% IAC.

Provision 103. An article in accordance with Provision 92 in which the cast metal contains aluminium or an aluminium alloy.

Provision 104. An article in accordance with Provision 103 in which the aluminium or aluminium alloy is in the form of stranded wire with steel reinforcement.

Provision 105. An article in accordance with Provision 103 in which the aluminium or aluminium alloy is in the form of stranded wire with a steel support.

Taking into account the above principles, many modifications and variations of the present invention are possible. It is therefore necessary to understand that within the scope of the appended claims, this invention may be practiced in a manner other than that previously specifically described herein.

Claims (11)

1. A metal product containing cast metal, wherein the cast metal has submillimeter grain size and contains less than 0.5 wt.% grain refiners, relative elongation in the range of 10-30% when subjected to a tensile force of 100 psi, and tensile strength in the range of 50-300 MPa. 2. The article according to claim 1, wherein the metal article has an electrical conductivity in the range of 45-75% of IAC, which is the electrical conductivity indicated as a percentage relative to IAC - the electrical conductivity of a conductor made of standard annealed copper. 3. The article according to claim 1, wherein said metal comprises less than 0.2% grain grinders. 4. The article according to claim 1, wherein said metal comprises at least one of the following: aluminum, copper, magnesium, zinc, lead, gold, silver, tin, bronze, brass and their alloys. 5. The article of claim 1, wherein said metal is formed to form at least one of the following: rods, bars, sheets, wire, billets or granules. 6. The article according to item 1, wherein said metal comprises aluminum or an aluminum alloy. 7. The article according to claim 6, wherein the aluminum or aluminum alloy is a twisted wire of a steel-reinforced cable. 8. The article according to claim 6, wherein the aluminum or aluminum alloy is a twisted wire of a cable with a steel support.