JP3522731B2 - Hot top mold - Google Patents

Abstract

The ingot mold, for a continuous casting assembly, has a hot head (1) on the upper side of a barrier distributor (2), held and centered by an outer ring (4) in a release mounting at the ingot mold (3). The mold is surrounded by a metal or ceramic function ring (5), to the mold running surface, forming function surfaces with adjustable roughness together with the barrier distributor. The barrier distributor has radial channels at the upper and lower sides, with channel cross sections in a ratio of 1:3 to 1:5 between the upper and lower sides.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot top mold, in particular, located at the upper part of a mold release agent delivery section, and presses the mold release agent delivery section against the mold by its bottom. An overhang is formed on the inner surface of the hot top, including the hot top, in the descending direction of the strands (thin bars), beyond the release agent delivery section and forming an annular gap with the inner surface of the mold. Relates to a hot top mold for a strand casting apparatus. [0002] EP 0 565 865 (VAW) discloses a hot top mold of the kind described above. The release agent or lubricant reaches the surface of the cast strand through the release agent delivery section. For example, two different release agents can be provided separately or as a mixture of a liquid release agent and a gaseous release agent or lubricant. It has been found particularly desirable that a mixture of oil and gas is first formed close to the mold. However, in this case, the surface quality is often inadequate and there are several problems associated with casting alloys that are difficult to cast. This is especially true for aluminum alloys containing lead, zinc, tin and copper. In recent years, they have become increasingly important in the production of special alloys and machined alloy materials used at high cutting speeds. Another problem is the precise control of the gas pressure, which is very important for the release agent to reach the entire surface of the metal strand. When the pressure fluctuates, wrinkles are easily generated on the surface. If the pressure is too high, the gas may leak through the molten metal. As a solution to this problem, US Pat.
32, 209 (Pechiney) proposes using a graphite ring. The open area ratio of the graphite is that the pressurized gas passes from the outside through the pores of the graphite material and enters the inside of the mold, and acts as a release agent between the surface of the metal strand being formed and the surface of the mold. Is set to However, our experience does not solve the problems in producing alloys that are difficult to cast by this method. [0006] The present invention has addressed the improvement of the above types of hot top molds in order to produce different types of alloys, particularly difficult to cast alloys, with satisfactory surface quality. As a result, the object is to provide a hot top mold for strand casting equipment that makes it possible to obtain improved surface properties in the casting of difficult to cast alloys, in particular aluminum alloys. is there. In order to achieve the above object, a hot top mold according to the present invention has the following features. (A) The hot tops 1 a and 1 b are held by an outer ring 4 that is detachably fastened to the mold 3. (B) The mold 3 and the mold release agent distributor (release agent distributor) 2 surround the functional ring 5 on the inner surface of the mold, and the functional ring 5 has a functional surface having an adjustable roughness on the surface. Form. (C) The release agent delivery unit 2 is made of a plate having radial conduction paths on both sides, and the ratio of the cross-section of the conduction paths on the top surface and the bottom surface is 1: 3 to 1: 5. According to feature (a), the new hot top mold is composed of several rings that are easy to assemble and disassemble. Therefore, according to a desired alloy, a different release agent delivery part and a functional ring can be replaced | exchanged rapidly. According to feature (b), the present invention consists in the use of a functional ring 5 having a functional surface opposite the mold release agent delivery section and the mold surface. The functional surface forms a wall surface having a predetermined roughness for the conduction path formed by the release agent distributor. Particularly preferably, the functional surface forms one wall for the cross-section of the conducting channel that conducts the fluid. Precisely adjusted surface roughness and temperature of the functional surface can cause a predetermined change in the viscosity of the fluid release agent to produce a stable foam layer. According to the feature (c), the ratio of the cross section of the conduction path in the release agent delivery section is important for controlling the composition of the release agent mixture. By combining the feature (b) and the feature (c), bubbles can be generated, and it is particularly effective as a release agent having a high viscosity. Also, very good surface quality can be obtained, especially in the case of alloys that are difficult to cast. DETAILED DESCRIPTION OF THE INVENTION Preferred embodiments of the present invention are enumerated as follows. (1) The hot top mold according to claim 1, wherein the functional ring (5) is made of copper or a copper alloy. (2) The hot top mold according to claim 1, wherein the functional ring (5) is made of ceramic or composite material. (3) The hot top mold according to claim 1, wherein the functional ring (5) is made of graphite. (4) The clamping ring (6) is arranged above the hot top (1a, 1b), and the hot top (1
a, 1b), release agent delivery part (3), functional ring (5),
The hot top mold according to claim 1, wherein the mold (3) is clamped and fixed by a clamping ring (6). (5) The functional ring (5) according to any one of claims 1 and 4, wherein the functional ring (5) has a closed porosity of 0 to 20% and a density of 1.5 to 10 g / cc. Hot top mold. (6) Upper surface (2a) of the release agent distributor (2)
The radial conduction path provided in the pipe is connected to the pressurized gas medium, and the radial conduction path provided on the bottom surface (2b) of the release agent delivery section (2) is connected to the pressurized liquid storage tank. The hot top mold according to claim 1, wherein the hot top mold is any one of (1) to (5). (7) A radial conduction path on the bottom surface of the release agent delivery section is configured like a sprayer, and the conduction path located outside the radial carrying the release agent delivery section (2) has a substantially square cross section. The hot top mold according to claim 1, wherein a rectangular cross section having a surface ratio of at least 1: 2 is formed on the radially inner outlet side. (8) A cooling conduction path (15) reaching the lower region of the release agent distributor (2) and the functional ring (5) is provided in the mold (3), and in the annular gap ( 11 ), The hot according to any one of claims 1 and (7), wherein heat is removed via a foam layer (16) produced by a gaseous and liquid medium and flowing out in the descending direction of the strand. Top mold. (9) The thermal conductivity at the bottom of the hot top (1b) is 1.5 to 2.0 times the thermal conductivity at the top of the hot top (1a). ~ (8)
Either hot top mold. (10) Upper part (2) of the release agent delivery part (2)
The hot top mold according to claim 1, wherein a) is covered with an activation ring (7). According to the configuration of the above (4), it is proposed that a clamping ring 6 capable of clamping the hot tops 1a and 1b, the release agent delivery unit 2 and the mold 3 is provided above the hot tops 1a and 1b. ing. If the tightening ring 6 and the outer ring 4 are loosened, the release agent distributor 2 and the functional ring 5 can be easily replaced. Therefore,
The cross-section of the surface and the conduction path that influence the generation of bubbles can be easily harmonized. According to the configuration of (5), the function ring 5
It is advantageous if the predetermined hermetic porosity and density are selected within a narrow range. In an additional experiment in which the functional ring 5 was cooled to keep the functional surface viscosity characteristic constant, further stability of the release agent foam could be achieved. The construction and operation of the functional surface and cooling will be further described in the following embodiments. As described above, the upper surface 2a of the release agent delivery section 2
Is preferably used to form a conducting path for conducting gas, and the bottom surface 2b is preferably used for a liquid release agent. The conduction path needs to be manufactured with very high accuracy, for example, by laser processing or chemical etching. According to the configuration of (7) above, the shape of the cross section of the radial conduction path of the release agent delivery section is important for the air content in the release agent. The ratio of the surface area of the conduction path is
It is important for the formation of release agent foam that is evenly distributed around the circumference. Under these conditions, the release agent is strong because it is formed with fine bubbles, and the liquid component of the release agent can be reduced. According to the configuration (8), the functional ring 5 is cooled by disposing a cooling conduction path in the mold 3 reaching the functional ring region. In this main cooling region, the temperature is maintained to optimize the action of the release agent. In the adjacent sub-cooling region, the cooling conduction path extends in the descending direction of the strand and enters the slot nozzle, so that heat is rapidly removed. Here, the pressure of the coolant is reduced and the coolant contacts the aluminum strands to further cool the strands. Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the overall view of FIG. 1, the components of the system used in strand casting are shown. As is apparent from the claims, the formation of a predetermined functional surface is important for the formation of a stable release agent foam. The functional surfaces are located above and below the release agent delivery unit and inside the functional ring 5.
The latter is in direct contact with the conduction path of the release agent distributor 3 and contributes to the generation of bubbles. As an addition to the functional surface innovation, an activation ring 7 is introduced which can be made of various materials. Activation ring 7 is positioned between the top 2a of the outer ring 4 and a release agent delivery unit 2. Therefore, the activation ring covers the upper part of the conduction path formed in the release agent delivery unit 2. The roughness of the activation ring is different from the roughness of the hot top 1b and can be adjusted according to the requirements specific to the release agent. At the same time, the temperature gradient of the release agent distributor 2 under the hot top 1b can be controlled. The mold 3 includes an outer ring 4 and a functional ring 5. By means of the clamping ring 6, the activation ring 7
System parts including are assembled. The mold 3 is completed by the bottom 8 and the pressure plate 9. FIG. 2 is for further explaining the basic structure of the hot top mold of the present invention. Here, an enlarged detail will be described, especially under the overhanging portion of the hot top 1b. An annular gap 11 is shown below the overhang. The side wall of the annular gap is formed on the one hand by the overhanging part of the hot top, and on the other hand the release agent delivery part 2.
The inner ring and the functional ring 5 are formed. When the gas-liquid release agent is fed within the volume ratio of the present invention, a stable release agent bubble is formed, and a continuous bubble layer is formed between the mold 3 and the strand 10. The viscosity of the release agent is controlled by the surface roughness in the gas region and the liquid region. The viscosity of the release agent is an essential factor in foam formation. In addition, by controlling the pressure and flow rate of the gas and liquid media supplied,
The composition of the release agent foam can be adjusted within a wide range. Further, the heat removal or heat insulation effect controlled by the release agent can be obtained. This is particularly advantageous for alloys that are difficult to cast. As described above, according to the present invention, improved surface quality can be obtained particularly in strand casting of alloys that are difficult to cast, such as aluminum alloys containing lead, zinc, tin, copper, and the like. There is provided a hot top mold from which the product can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view of the entire hot top mold of the present invention. FIG. 2 shows the hot top mold of the present invention in strand casting. [Explanation of Symbols] 1a Hot Top 1b Hot Top 2 Mold Release Agent Distributing Section (Mold Release Agent Distributor) 2a Top Surface 2b Bottom Surface 3 Mold 3a Surface 4 Outer Ring 5 Function Ring 6 Clamping Ring 7 Activation Ring 8 Bottom 9 Pressure Plate 10 Metal strand 11 Annular gap 12 Mold release agent bubble 14 Annular gap 15 Cooling channel 16 Foam layer

Front page continuation (72) Inventor Manfred Langen Germany 53227 Bonn Eichendorf Strasse 11 (72) Inventor Stefan Inston Germany 53117 Bonn Friedrich-Worler Straße 5 (56) Reference European Patent Application Publication No. 566865 (EP, A 1) US Patent 4732209 (US, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B22D 11/041 B22D 11/00

Claims (1)

(57) [Claims] [Claim 1] Located on the upper surface (2a) of the release agent delivery section (2), the bottom surface (2b) of the release agent delivery section (2) is used as a mold (3).
Hot top (1a, 1) pressed against the upper surface (3a)
b), the inner surface of the hot top (1a, 1b) protrudes beyond the release agent distributor (2) in the direction of drawing out the strand (10) , and the annular surface (11) from the mold surface. A hot top mold for strand casting in which an overhang forming part is formed, the hot top (1a, 1b) being centered and held by the outer ring (4), the outer ring (4) being removably secured to the template (3), the upper surface of the mold (3) surrounds a function ring in the inner surface of the mold with release agent delivery section (2) (5), the release agent formulation unit (2) (2a) and bottom surface (2
In b), gas and liquid are introduced as mold release agents, respectively.
A radial conduction path is formed and passes through the release agent distributor (2).
The release agent foam (12) is guided by the functional ring (5).
Function ring to be generated between the lands (10)
The surface of (5) has an adjusted surface roughness,
Conduction path formed on the upper surface (2a) of the release agent blending part (2)
A hot top mold characterized in that the ratio of the cross section of the conductive path formed on the bottom surface (2b) is 1: 3 to 1: 5.