JPS58192661A - Production of casting mold for continuous casting - Google Patents

Abstract

PURPOSE:To cast an ingot having good quality, by plating specific metal on the inside surface of a casting mold made of copper and further forming the melt sprayed film of a self-fluxing alloy thereon then subjecting the film to a remelting treatment, thereby protecting the surface of the casting mold against damage and deformation over a long period of time. CONSTITUTION:Plating 2 of nickel, iron, cobalt or their alloy is applied on part or the whole of the inside wall surface of a water-cooled casting mold 1 made of a blank material of deoxidized copper or precititation hardening type copper alloy. A melt sprayed film 3 of a self-fluxing alloy is then formed thereon. The film 3 is further subjected to a remelting treatment with a beam or an arc heat source which is moved without any thermal influence on the base material of the mold 1. The self-fluxing alloy is produced by adding MO, WC, TiO2, etc. properly to the essential components of Ni-Cr-B-Si according to characteristics, and an electron beam or the like generated by converging about >=2,000 Joule/ cm<2> energy to within about 10mm. diameter is used as the heat source to be used for the remelting.

Description

[Detailed Description of the Invention] This invention enables the casting of high-quality slabs by protecting the mold from deformation over a long period of time, and is applied to part or all of the inner surface of the copper or copper alloy constituting the mold. After plating at least one of nickel, iron, cobalt, or their alloys, and then forming a thermally sprayed coating of a self-fusing alloy, the coating is remelted by locally heating only the surface layer without affecting the base material. The present invention relates to a method for manufacturing copper molds for continuous casting, which is characterized by a bamboo treatment.

Most molds for continuous casting are made of steel, but the copper near the molten steel injection surface is severely damaged in a short period of time, resulting in the infiltration of Km into the molten steel, which is the cause of cracks in cast slabs. make.

Furthermore, the parts that come into contact with the solidified slab shell are subjected to severe abrasion and are also subjected to high drought steam corrosion due to water-cooled water.

Conventionally, various methods of coating steel surfaces have been attempted in order to improve the quality of cast products and at the same time prevent damage and deformation of the copper mold. However, no method has yet been proposed that would make a fundamental improvement.

A few examples of conventional methods include plating the copper surface with nickel, cobalt, iron or their alloys by electroplating or electroless plating, and using fine particles of hard 5 in the plating film, which has excellent lubrication performance. There are methods such as dispersing and precipitating particles, methods using thermal spraying, and methods using explosive deposition of hard IM metals, but none of these methods has reached the point of solving the problem of type life and operational issues.

Among the above-mentioned known examples, plating methods such as nickel use heat treatment by heating the entire body as a means of improving adhesion, and thermal spraying methods require remelting treatment to improve adhesion. .

After heating the entire copper mold through such heat treatment, deterioration of the mechanical properties of the copper is unavoidable.Although heat treatment as a treatment is a means of restoring the properties, changes in shape cannot be prevented, so vJffA Disadvantages in maintenance operations are pointed out.

The present invention is based on the above-mentioned knowledge, and as a result of repeated experiments to eliminate the drawbacks of the conventional technology, the present invention has been developed to create a thermal spray coating that can withstand harsh casting conditions for a long period of time without causing any adverse thermal effects on the mold base material. was able to provide the following.

By the way, in the past, after spraying a self-fusing alloy to form a film, remelting of the film was performed as a post-process to metallurgically adhere the film to the base material and eliminate pores in the film to make it denser. It's lacking in J.

There are several methods for this, including heating with a gas flame, heating in a heating furnace, and induction heating.
~1] It is necessary to heat the material to 00°C, but as a result of heating the entire base material at the same time as heating the film, thermal effects on the material cannot be avoided as a natural result.

When a self-fusing alloy is sprayed onto mold steel and the coating is remelted, heat treatment is used as a means of recovering the strength of the mold steel due to high-temperature heating, but shape changes due to thermal distortion are an unavoidable problem. The remaining operational troubles related to the use of type # cannot be resolved.

In order to eliminate such adverse effects in the remelting process, the present invention has discovered a method of forming a self-fusing alloy film that does not have an adverse thermal effect on the mold copper plate by using an electron beam, light beam, or arc heat as a heating heat source. It is something that

Embodiment F will be specifically described below based on the drawings.

A1. When using steel or precipitation-strengthened steel, fM material is coated with nickel, iron, cobalt, or their alloys on part or all of the inner wall surface of water-cooled M-type 1. A soluble alloy spray coating 3 is formed. Next, a beam or an arc heat source is passed over the coating 3 to heat it and perform a remelting process to complete the coating.

The plating film used in the present invention is essential for the diffusion of the subsequent thermal sprayed layer and the formation of a bonding layer by diffusion of the plating onto the base steel, but the plating thickness is not particularly limited. In the inventor's examples, good results were obtained with -F of 10 p or more.

Furthermore, although known self-fluxing alloys used for thermal spraying are sufficient, in addition to the main components of the Ni-Or-B-8i system, the characteristics required differ depending on the part of the mold to be thermally sprayed, so it is necessary to One or more additives such as M O% W 0% T IOJ are appropriately selected and blended.

The heat source used for remelting the sprayed layer may be an electron beam, light beam, or arc heat, but 2000"7c++!
The above energy is converged and used within a diameter of 10 m1111. According to this heating method, the 1M diameter of the remelting pool is 1
It has been actually measured that the depth that is heated within 0M remains within 2B.

The thermal spray coating of the molded copper plate produced by the manufacturing method of the present invention includes a copper base material,
The lower layer plating and self-fusing alloy are each in phase! I [diffuses and forms a dense film with strong adhesion and no pores]
Moreover, the base steel retains its original mechanical properties without being affected by any adverse thermal effects during the film formation process. And the provision of long-lasting mold steel is 61
It can be said that this has a great effect on improving the quality of cast products and reducing equipment costs.

[Brief explanation of the drawing]

The drawing is a perspective view showing a part of a four-continuous casting mold according to the manufacturing method of the present invention. 1. Mold, 2. Plating layer, 3. Thermal spray coating. Patent applicant: Kyushu Seishu Kanagawa Kogyo Co., Ltd. company

Claims (1)

[Claims] (1) Part or all of the inner surface of the copper or copper alloy constituting the mold is plated with at least one of nickel, iron, cobalt, or their alloys, and then a sprayed coating of a self-fusing alloy is formed on the 1d material. A mold manufacturing method for continuous casting that is characterized by locally heating only the surface layer and remelting the coating without having a thermal effect on the surface layer.