JPS5950950A - Production of tube mold - Google Patents

Abstract

PURPOSE:To produce easily a tube mold of a small size for continuous casting by covering a metallic case for the mold on a refractory core having the same outside shape as the inside surface shape of the mold, evacuating the spacing between said case and core and subjecting the same to hot isotropic pressurization. CONSTITUTION:A core 1 having the same shape as the internal space shape of a tube mold for continuous casting is manufactured from refractories such as alumina. A case 2 made of a metallic material to be made into the tube mold, that is, a metallic material having Cu or a Cu alloy on the outside and Ni or an Ni alloy layer on the inside is put on the outside of such core 1. A slight spacing is provided inbetween by winding a wire rod or belt-like material on the outside of the core 1, and is evacuated to a vacuum after the contact parts of the core 1 and the case 2 are hermetically sealed by means of an adhesive agent 3. Both are subjected to a hot isotropic pressurization treatment using a gaseous substance at high temp. and high pressure to adhere tightly the case 2 to the core 1, whereafter the core is removed and the tube mold for continuous casting is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a tube mold used for manufacturing relatively small slabs in a continuous casting mold.

This type of chive mold is, for example, a straight tube-shaped mold whose inner diameter gradually decreases from the top to the bottom as shown in Figure 1, or a straight tube whose inner diameter gradually decreases from the top to the bottom as shown in Figure 2. The inner diameter is small and the overall shape is slightly curved. Usually, a mold body (1) made of copper or prepared alloy is coated with a wear-resistant coating layer (2) of nickel or its alloy on the inner surface.

This chive mold generally has a small inner diameter but a large length in the vertical direction, and it is even more difficult to polish the inner surface of the mold if it is curved. However, since the inner diameter of the chive mold requires precise finishing dimensions, the finishing process is currently accompanied by many difficulties.

The present invention aims to provide a method for manufacturing a tube mold having an accurate and smooth inner surface without the above-mentioned difficulties. After placing the pipe on the outer periphery of the core that matches the inner space shape of the tube mold, the outer surface contact between the core and the pipe is made airtight, and the inside of the pipe is evacuated to create a vacuum state. This method of manufacturing a tube mold is characterized in that the pipe is brought into close contact with the outer surface of the core by hot isostatic pressure treatment, and then the core is removed.

The present invention will be described in detail with reference to the drawings. First, a core (1) as shown in FIG. 6 is prepared. The core (1) is made of ceramic such as alumina or other heat-resistant material, and may be assembled from a plurality of divided pieces as long as the outer shape can be maintained. In any case, the outer shape should match the desired shape of the internal space of the chive mold.
In this case, since the outside is processed, the processing is easy and the processing accuracy can be sufficiently accurate.

A pipe (2) is placed around the outer periphery of such a core (1), and this pipe is formed into a chive mold by hot isostatic pressing as described in detail below.
The material for the pipe (2) is usually copper or copper alloy, which has good thermal conductivity, but this pipe (2) is composed of multiple pipes, and the outside is made of copper or a prepared alloy, and the inside is made of heat-resistant and abrasion-resistant nickel or a nickel alloy. If this is done, a tube mold having a coating layer having the desired properties on the inner wall surface will be manufactured. In addition to the method of providing a coating layer on the inner wall surface, there are two methods of providing a coating layer on the inner wall surface:
Before overturning the pipe (2), there is a method of wrapping a linear or band-shaped material made of a material with properties desired as a coating layer on the inner wall surface around the outer circumference of the core (1), or a method with a slightly larger diameter. Using pipe (2), insert core (1) and pipe (2)
This can also be achieved by a method such as creating a gap between the two and filling the gap with a powder material made of the required material.

Next, in either method, the outer periphery of the pipe (2) is sealed as airtight as possible, and the inside of the pipe (2) is evacuated. Heat-resistant adhesive is used for airtight sealing (3)
A lid made of a material that seals the outer surface contact between the core (1) and the pipe (2), or can be welded to the pipe (2) on the top and bottom surfaces as shown in Figure 6. There is a method of abutting (4) and sealing with a welded part (5) by electron beam welding, or a method of covering the entire circumference with a case made of a suitable material such as metal or glass.

After the object is made airtight and in a vacuum state, the entire object is subjected to hot isostatic pressure treatment, that is, the entire object is subjected to a hot isostatic pressure treatment in a high temperature range via an appropriate gas for operation such as nitrogen gas or argon gas. A process is performed in which high pressure is applied from the periphery. This hot isostatic pressure treatment varies depending on the composition, thickness, etc. of the pipe (2) used, but the temperature is usually 500 to 1000°C,
The pressure is maintained at 100 to 400 atmospheres for 1 to 5 hours. In addition, since high-temperature heating and holding is performed in this way, the material for the pipe is precipitation-hardened chromium-copper, beryllium-copper, chromium-zirconium-copper, etc., and is rapidly cooled after hot isostatic pressure treatment (solution treatment). It is preferable to carry out precipitation hardening by aging heating.

By performing the hot isostatic pressure treatment as described above, the pipe (2) is pressed from its entire outer periphery, and the void inside the pipe (2) is degassed and becomes a vacuum state, so the pipe ( 2
) is pressed against the outer surface of the core (1) and is plastically deformed so that the inner surface of the pipe (2) is in complete contact with the outer surface of the core (1). After that, remove the heat-resistant adhesive (3) or the lid (4) and pull out the core (1), and the inner surface shape will be the same as that of the core (1).
A pipe (2), that is, a chive mold, is obtained which matches the external shape of the pipe (2).

In the above manufacturing process, if the tube mold has a shape that gradually decreases in diameter from the top to the bottom and/or has a curved shape, if the pipe used is straight, the core There will be some areas where there will be a large gap between the pipe and the pipe.

This requires more effort when degassing, and the deformation of the pipe becomes larger during the subsequent hot isostatic pressure treatment, so especially in cases such as the outer periphery of the core. A method in which a linear or band-shaped material is wound around the pipe, or a method in which a powder material is interposed between the core and the pipe can fully exhibit the effect.

In other words, by partially changing the linear or band-like material wrapped around the outer circumference of the core, which has a reduced diameter and/or a curved shape from the upper part to the lower part, after the linear or band-like material is wrapped. Either the core has a straight bar shape with approximately the same diameter from the top to the bottom, or the powder material is inserted only in the large gap after the pipe is covered with the core, or the thickness of the material is partially varied. This is because all you have to do is brush it off. The linear or strip material used in these cases is made of the same material as the pipe, and the stone and the resulting Dave mold are made entirely of the same material, and as mentioned above, the innermost surface is made of a heat-resistant and wear-resistant material. If the outside surface is made of the same material as the pipe, a chive mold whose inside wall surface is coated with a heat-resistant and wear-resistant material can be obtained.

As described above, according to the method of the present invention, as long as the shape of the internal space roughly matches the shape of the internal space of the target chive mold, even if the shape is different in terms of detailed dimensions, tabularity, etc. A chive mold having a desired internal space shape that matches the outer shape of the core can be easily obtained by hot isostatic pressing. And processing to make the outer shape of the core match the inner space shape of the tube mold.

Since this is the processing of the outer shape, it is much easier and more accurate than processing the inner wall surface of a tube mold, and the core can be used many times, making it highly suitable for mass production.

Furthermore, in the method of the present invention, the pipes used can be made into multiple pipes as described above, and it is also easy to treat the pipes by interposing linear or band-shaped materials or powder materials having desired properties such as wear resistance. Therefore, it is possible to simultaneously create a coating layer on the inner wall surface of the resulting chive mold, and especially in the method of interposing a linear or strip material or powder material, the inner surface of a regular continuous casting mold can be coated. It has the advantage that it can easily coat materials that are difficult to coat using coating methods such as plating and thermal spraying, such as composite materials such as metal and ceramic, and ceramic materials.

[Brief explanation of drawings]

1 and 2 are perspective views showing the general form of a chive mold, FIG. 3 is a perspective view of a core used in the method of the present invention, and FIG. 4 is a perspective view of a pipe used in the method of the present invention. 5 and 6 are explanatory diagrams each showing an example of an airtight treatment state in the method of the present invention. In the diagram, (1): Core (2): Vibrator patent applicant Kuroki Kogyo Co., Ltd. Agent Noriharu Ariyoshi 1st
[゛ri de 1 2nd
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4th 1st 1st 5th
11'? <I Fig. 6b Written amendment to the procedure (Fotonu) February 24, 1980 1 Indication of f'l 1982 Patent No. 160171 2 Title of invention Method for manufacturing tube mold 3 Supplement 1-Relationship with 'l Name of patent applicant 11 Kuroki Kogyo Co., Ltd. 6° Supplement "1" 0
° Text 7, Contents of amendment [Engraving of specification (no change in content)”

Claims (1)

[Claims] On the outer periphery of the core, which is made of IH thermal material and whose outer shape matches the desired internal space shape of the chive mold,
After the pipe is overturned, the outer surface fusion part between the core and the pipe is made airtight, and the inside of the pipe is evacuated to create a vacuum state.
A method for manufacturing a tube mold, comprising: then removing the core after bringing the pipe into close contact with the outer surface of the core by hot isostatic pressure treatment. The method for manufacturing a tube mold according to claim 1, wherein one vibrator is a multiple tube. 8. A method for manufacturing a Dave mold according to claim 1, characterized in that a linear or band-like shape is wound around the outer periphery of the core. 4. The method of manufacturing a tube mold according to claim 1, wherein a powder material is interposed between the vibrator and the core.