CN117047054A - Method for detecting shape of continuous casting solid-liquid interface - Google Patents

Abstract

The invention provides a method for detecting the shape of a continuous casting solid-liquid interface, which comprises the following steps: firstly adding a first metal into a melting furnace to obtain a first metal melt, then obtaining a first metal rod blank through continuous casting, adding a second metal with obvious difference from the first metal in color into the melting furnace after a certain period of time to obtain a mixed metal melt, obtaining a mixed metal rod blank through continuous casting, and finally detecting the interface shape of the junction of the first metal rod blank and the mixed metal rod blank, wherein the interface shape is the solid-liquid interface shape in the continuous casting process. The invention is based on changing the melt metal components at the initial stage and the later stage of the rod blank in the continuous casting process, so that the rod blank formed in different periods has obvious color and state difference, the rod blank formed in different periods forms a junction which is easy to identify, and the interface shape of the junction is the solid-liquid interface shape in the continuous casting process.

Description

A method for detecting the shape of solid-liquid interface in continuous casting

Technical field

The invention belongs to the field of non-ferrous metal processing, and specifically relates to a method for detecting the shape of solid-liquid interface in continuous casting.

Background technique

The metal rod blank is the original blank from which the wire rod is drawn. The quality of the rod blank determines the quality of the wire rod. Continuous casting technology is a common process for producing metal rod blanks. It is different from the mold casting method. During the continuous casting process, the metal melt passes through the crystallizer and rapidly solidifies and crystallizes in the crystallizer. The solidified rod blank in the crystallizer is moved by a traction device. Pulling out is an efficient and continuous production process. This technology combines continuous casting and directional solidification, using a heated crystallizer mold instead of a traditional cooling mold. When the metal melt passes through the crystallizer, the temperature is still above the melting point, and the solid-liquid interface is located at the end of the crystallizer, so that the crystal grains are Nucleation is formed at the outlet, and a large temperature gradient can be established along the continuous casting direction to obtain unidirectionally solidified single crystals or columnar crystals. The elongation rate is much higher than that of ordinary cold-type continuous casting polycrystalline alloy casting rods, and The problem of defects in the cast slab is reduced, the cast slab with smooth surface quality can be obtained, and the plastic processing performance of the cast rod is greatly improved.

Continuous casting to prepare rod blanks with directional solidification structure is the prerequisite for obtaining high-performance wire rods. The single crystal structure is conducive to improving fine deformation ability and conductive properties. The shape of the solid-liquid interface during the continuous casting process determines the solidification structure characteristics. Relevant studies have shown that the solid-liquid interface shape of cold continuous casting is concave, and the solidification structure is mainly radial equiaxed crystals; the solid-liquid interface shape of hot continuous casting is convex or planar, and the solidification structure is axial columnar. Mainly crystal or single crystal structure. Therefore, obtaining a convex solid-liquid interface shape through hot continuous casting is an effective means to achieve single crystal structure.

The key to obtaining a stable single crystal structure in hot continuous casting is the precise control of the shape of the solid-liquid interface. The curvature radius of the solid-liquid interface directly affects the grain competitive growth efficiency and crystal orientation. In the early stage of single crystal structure formation in continuous casting, the structure evolution pattern is rapid elimination of grains→competitive growth of columnar crystals→single crystal formation. The curvature radius of the solid-liquid interface determines the competitive growth behavior of grains. A smaller curvature radius is conducive to improvement. The efficiency of single crystal structure formation; in the stable growth stage of the single crystal structure in the later stages of continuous casting, the curvature radius of the solid-liquid interface determines the crystal orientation of the single crystal structure. A larger curvature radius or a smooth solid-liquid interface is conducive to obtaining a single crystal structure with a smaller orientation. crystal structure. Therefore, the shape of the solid-liquid interface is a key factor affecting the continuous casting process and the quality of the rod blank.

However, during the solidification process of horizontal continuous casting, the solid-liquid interface is inside the crystallizer, making it difficult to directly observe and measure its shape and curvature characteristics. The traditional method of studying the shape of the solid-liquid interface is mainly numerical simulation. The numerical simulation method uses software to simulate and predict the shape of the solid-liquid interface by integrating material, process and other parameters. However, the accuracy of the simulation is difficult to verify and the reliability of the simulation results cannot be determined. Alternatively, the method of water quenching is used to pull the rod blank during the continuous casting process to a certain length, then carry out overspeed traction and artificial liquid quenching to fix the shape of the solid-liquid interface, and conduct macroscopic observation of the end of the rapidly quenched rod blank. However, this method also has problems: (1) During the overspeed pulling process, the melt leaks from the crystallizer, and inevitably part of the melt is brought out by the rod blank, which then forms a tail at the end of the rod blank, affecting the observation of the solid-liquid interface. ; (2) High-temperature melt leaks during overspeed traction, which not only wastes material, but also poses certain risks.

As an improvement, the Chinese invention patent application with application publication number CN115673273A and application publication date of February 3, 2023 discloses a method and device for detecting the shape of the solid-liquid interface in continuous casting during the continuous casting process. The liquid level control rod in the furnace causes the melt in the crystallizer connected to the furnace to quickly flow back to the furnace. The melt liquid level in the furnace is lower than the liquid level in the mold cavity, forming a current moment at the end of the rod blank. The shape of the solid-liquid interface. The shape of the solid-liquid interface obtained by this method can be directly observed, and the operation occurs in a closed crystallizer and furnace, thus avoiding material waste and melt leakage. However, it can be found that the shape of the solid-liquid interface obtained by this method through external force interference (controlling the movement of the liquid level control rod) is somewhat different from the shape of the solid-liquid interface in the normal continuous casting process. It is not the shape of the solid-liquid interface in the normal continuous casting process. A true reflection of the shape of the liquid interface; in addition, the shape of the solid-liquid interface obtained by this method is the shape of the interface at a specific moment, and cannot completely reflect the shape of the solid-liquid interface during the continuous casting process.

Contents of the invention

The object of the present invention is to provide a continuous casting solid-liquid interface shape detection method to solve the problem of shape distortion of the solid-liquid interface obtained through external force interference, and the obtained solid-liquid interface shape is the interface shape at a specific moment. It cannot truly reflect the shape of the solid-liquid interface during continuous casting.

In order to achieve the above purpose, the detection method of the continuous casting solid-liquid interface shape in the present invention adopts the following technical solution:

A method for detecting the shape of solid-liquid interface in continuous casting, which includes first adding a first type of metal into a furnace and obtaining a first metal melt, then obtaining a first metal rod blank through continuous casting, and after a certain period of time, adding a combination of For the second type of metal with obvious difference in color from the first type of metal, a mixed metal melt is obtained, and a mixed metal rod blank is obtained through continuous casting. Finally, the interface shape at the junction of the first metal rod blank and the mixed metal rod blank is detected. The interface The shape is the shape of the solid-liquid interface during continuous casting.

The beneficial effect of the above technical solution is that the invention is a pioneering innovation. The invention is based on changing the molten metal composition of the rod blank in the early and late stages during the continuous casting process, so that the rod blanks formed in different periods have obvious differences in color and state. The rod blanks formed at different stages form an easily identifiable junction, and the interface shape at this junction is the shape of the solid-liquid interface during the continuous casting process.

Further, the interface shape at the junction of the first type metal rod blank and the hybrid metal rod blank is obtained by half-section extending in the axial direction at the interface between the first type metal rod blank and the hybrid metal rod blank.

The beneficial effect of the above technical solution is that with such an arrangement, by cutting the rod blank including the junction, the shape of the solid-liquid interface can be more intuitively and completely reflected than by observing through the surface layer.

Further, the certain period of time is from the start of drawing the rod blank to the stable drawing state of the rod blank.

The beneficial effect of the above technical solution is that with such an arrangement, the second type of metal that is obviously different from the first type of metal is added only after the drawing state of the first type of metal rod blank is stable, so as to avoid poor quality of early rod blank drawing and forming. And affect the interface shape acquisition.

Further, the mass part of the second type of metal added is 1% to 20% of the mass part of the mixed metal melt in the furnace after adding the second type of metal.

The beneficial effect of the above technical solution is that such an arrangement, by adding an appropriate content of the second type of metal, is sufficient to change the color of the subsequent rod blank to the first type of metal melt, so that the drawn mixed metal rod blank can be formed into It has an obvious color difference from the first type of metal rod blank, and at the same time, it will not cause a waste of mixed metal rod blanks after the continuous casting is completed.

Further, the first type of metal and the second type of metal are both non-ferrous metals, and the first type of metal and the second type of metal are of different types.

The beneficial effect of the above technical solution is that such a setting can be applied to the detection of the shape of the solid-liquid interface in the continuous casting process of non-ferrous metals. By adding a second type of metal that is different from the first type of metal and has a different color, an obvious result can be obtained. The rod blank existing at the junction can then obtain the solid-liquid interface shape.

Further, the first type of metal is a single metal or alloy.

The beneficial effect of the above technical solution is that such an arrangement can detect the shape of the solid-liquid interface during continuous casting of a single metal or an alloy dominated by a single metal.

Further, the first type of metal is copper or copper alloy.

The beneficial effect of the above technical solution is that with such an arrangement, copper or copper alloy is easy to process and draw to form a dry blank, and it is easy to add a second type of metal that is different from copper or copper alloy.

Further, the second type of metal has white luster.

The beneficial effect of the above technical solution is that with such an arrangement, the white glossy metal can easily dilute the pure copper melt, thereby causing changes in the color of the surface and core of the mixed metal rod blank, and it is easy to form a visible difference with the pure copper rod blank. , easy to identify the interface shape.

Further, the first type of metal is copper or copper alloy, and the second type of metal is one or more of silver, tin, aluminum, and chromium with white luster.

The beneficial effect of the above technical solution is that with such an arrangement, when the first type of metal is copper or copper alloy, silver, chromium, tin, and aluminum with white luster are easy to form a mixed metal rod blank with copper, and have obvious interaction with copper. The difference in color makes it easier to identify the mixed metal rod blank from the pure copper rod blank, thereby obtaining a rod blank with an obvious junction, and then the solid-liquid interface shape can be obtained.

Description of the drawings

Figure 1 is a schematic diagram of the method for detecting the shape of the solid-liquid interface in continuous casting according to the present invention.

Detailed ways

The features and performance of the present invention will be described in further detail below with reference to examples.

Embodiment 1 of the method for detecting the shape of solid-liquid interface in continuous casting in the present invention:

The invention is based on changing the molten metal composition of the rod blanks in the early and late stages during the continuous casting process, so that the rod blanks formed in different periods have obvious differences in color and state, and the rod blanks formed in different periods form an easily identifiable junction. The interface shape at the junction is the shape of the solid-liquid interface during continuous casting.

As specifically shown in Figure 1, the continuous casting solid-liquid interface shape detection method in the present invention is based on changing the early and late solidification structural characteristics of the rod blank during the continuous casting process, thereby restoring the solid-liquid through the characteristics of the junction of the two structures. Interface shape. Specifically, the furnace is initially filled with a first-type metal melt, and the first-type metal rod blank is formed through continuous casting, and its solidification structure is the first-type metal solidification structure. In this embodiment, the first-type metal is copper, and the solidification structure is Pure copper solidification structure; after continuous casting for a period of time, a second type of metal that is obviously different in color from copper is added to the furnace during replenishment. At this time, the melt in the furnace becomes a copper alloy melt. After this time, continuous casting As the casting continues, the solidified structure will also become the copper alloy solidified structure; after the continuous casting is completed, due to the obvious difference in color and organizational state between the pure copper solidified structure and the copper alloy solidified structure visible to the naked eye, the junction is clearly visible. This junction The shape at is the shape of the solid-liquid interface during continuous casting.

In this embodiment, the furnace is initially filled with pure copper melt, and a pure copper rod blank is formed through continuous casting; after the drawing state of the rod blank is stable, solid or molten silver (Ag) is added during replenishment, and the furnace is controlled. The Ag content in the internal melt is 2%; continuous casting continues after this point. Due to the addition of Ag element, the melt changes from pure copper to Cu-2Ag alloy, and the rod blank will also change from pure copper rod blank to Cu-2Ag alloy. 2Ag alloy rod billet, at this time, the color of the surface layer and core of the rod billet will undergo obvious changes visible to the naked eye, and the solidification structure will also change; after the continuous casting is completed, the interface shape at the junction of the surface colors will be observed to obtain the solidification process during the continuous casting process. The shape of the liquid interface, or the interface shape at the junction of the pure copper rod blank and the alloy rod blank on the cross section can be obtained by half-section extending along the axial direction at the junction of the pure copper rod blank and the alloy rod blank, which is obtained during the continuous casting process. The shape of the solid-liquid interface.

In this embodiment, the content of added Ag is 2% by mass of the Cu-Ag mixed melt mixed in the furnace after adding Ag. In other embodiments, the content of added Ag is 2% by mass of the pure copper melt in the furnace when Ag is added.

It should be noted that in this embodiment, although the Ag element requires a certain diffusion time from being added to the furnace to being evenly distributed in the melt, the continuous casting solid-liquid interface shape detection method of the present invention does not require the uniformity of the distribution of metal elements. It only focuses on the change of solidification structure, that is, from pure copper to impure copper, so it does not affect the reduction of the shape of the solid-liquid interface.

The invention changes the molten metal composition of the rod blanks in the early and later stages, so that the rod blanks formed in different periods have obvious differences in color and state. The rod blanks formed in different periods form an easily identifiable junction, and the interface shape of the junction That is the shape of the solid-liquid interface during continuous casting.

Embodiment 2 of the method for detecting the shape of solid-liquid interface in continuous casting in the present invention:

In Example 1, after Ag is added to the pure copper melt, a Cu-2Ag alloy melt is formed and a Cu-2Ag alloy rod blank is obtained by continuous casting until the end of continuous casting. In this embodiment, after the Cu-2Ag alloy is continuously cast for a certain period of time, other second-type metals that are different from the Cu-2Ag alloy can be further added to form a mixed metal rod blank, thereby obtaining a rod blank with multiple junctions. Multiple solid-liquid interface shapes are then obtained.

Embodiment 3 of the method for detecting the shape of solid-liquid interface in continuous casting in the present invention:

In Example 1, the Ag content in the melt in the furnace is 2% by mass of the Cu-Ag mixed melt. In this embodiment, the content of Ag can be 1%, 3%, 5%, 10%, 15%, or 20%. Specifically, the content of Ag can form an obvious color difference from the pure copper rod blank.

Embodiment 4 of the continuous casting solid-liquid interface shape detection method in the present invention:

In Embodiment 1, the first type of metal is copper, and the second type of metal is silver (Ag). In this embodiment, the second type of metal may be one or more of tin and aluminum. In other embodiments, the first type of metal may be copper alloy, and the second type of metal may be one or more of manganese and chromium.

Embodiment 5 of the method for detecting the shape of solid-liquid interface in continuous casting in the present invention:

In Embodiment 4, the first type of metal is copper, and the second type of metal is one or more of tin, aluminum, and chromium. In this embodiment, the first type of metal is one or more of silver, tin, aluminum, and chromium, and the second type of metal is copper; in other embodiments, the second type of metal is a copper alloy.

Embodiment 6 of the method for detecting the shape of solid-liquid interface in continuous casting in the present invention:

In Example 1, the second type of metal has a white luster. In this embodiment, the second type of metal may not be a metal element with white luster. For example, when the first type of metal is a metal with white luster such as silver, chromium, tin, aluminum, etc., the second type of metal may be copper or Copper alloy.

Embodiment 7 of the method for detecting the shape of solid-liquid interface in continuous casting in the present invention:

In Example 4, when the second type of metal is chromium, the chromium content in the melt in the furnace is 20% by mass of the copper-chromium mixed melt, or it can be 10% or 15%, specifically to be able to form the same The content of pure copper rod blanks with obvious color differences is appropriate. In other embodiments, when the second type of metal is a metal other than silver and chromium, the content of the second type of metal in the melt in the furnace is preferably a content that can form an obvious color difference from the pure copper rod blank.

Embodiment 8 of the method for detecting the shape of solid-liquid interface in continuous casting according to the present invention:

In Example 1, the Ag content in the melt in the furnace is 2% by mass of the Cu-Ag mixed melt. In this embodiment, the Ag content is 2% by mass of the pure copper melt in the furnace. In other embodiments, the Ag content can be 1%, 3%, 5%, 10%, 15%, or 20%. , specifically the content that can form an obvious color difference from that of pure copper rod blank is appropriate.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. The patent protection scope of the present invention shall be subject to the claims. Any equivalent structural changes made using the contents of the description and drawings of the present invention, Likewise, they should all be included in the protection scope of the present invention.

Claims (9)

1. A method for detecting the shape of the solid-liquid interface in continuous casting, which is characterized by including: first adding a first type of metal into the furnace and obtaining a first metal melt, and then obtaining a first metal rod blank through continuous casting for a certain period of time. After this step, a second type of metal that is significantly different in color from the first type of metal is added into the furnace to obtain a mixed metal melt, and a mixed metal rod blank is obtained through continuous casting, and finally the interface between the first metal rod blank and the mixed metal rod blank is detected. The interface shape at is the shape of the solid-liquid interface during continuous casting. 2. The continuous casting solid-liquid interface shape detection method according to claim 1, characterized in that, by half-section extending along the axial direction at the junction of the first metal rod blank and the mixed metal rod blank, the third metal rod blank is obtained. The interface shape at the junction of a type of metal rod blank and a mixed metal rod blank. 3. The continuous casting solid-liquid interface shape detection method according to claim 1 or 2, characterized in that the certain period of time is from the beginning of drawing the rod blank to the stable drawing state of the rod blank. 4. The method for detecting the shape of solid-liquid interface in continuous casting according to claim 1 or 2, characterized in that the mass part of the second type of metal added is 1 mass part of the mixed metal melt in the furnace after the second type of metal is added. %~20%. 5. The continuous casting solid-liquid interface shape detection method according to claim 1 or 2, characterized in that the first type of metal and the second type of metal are non-ferrous metals, and the first type of metal and the second type of metal Different categories. 6. The continuous casting solid-liquid interface shape detection method according to claim 5, characterized in that the first type of metal is a single metal or an alloy. 7. The continuous casting solid-liquid interface shape detection method according to claim 6, characterized in that the first type of metal is copper or copper alloy. 8. The continuous casting solid-liquid interface shape detection method according to claim 7, characterized in that the second type of metal has white luster. 9. The continuous casting solid-liquid interface shape detection method according to claim 1 or 2, characterized in that the first type of metal is copper or copper alloy, and the second type of metal is silver, tin, etc. with white luster. One or more of aluminum and chromium.