JPS5847258B2 - Renzokuchi Yuzo Youchi Yugatanoseizou Hohou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a continuous casting mold, and more particularly to an improvement in a method for manufacturing a mold body by forming a copper mold body and then applying nickel plating to the inner surface of the casting hollow part of the mold body. be.

That is, the applicant has already filed a patent application for Japanese Patent Publication No. 48-28255 for the purpose of providing a mold that has good thermal conductivity, can withstand thermal stress and mechanical wear, and has excellent cooling performance and durability. We have just proposed the invention of No. 123589/1973.

However, when performing nickel plating on the inner surface of the casting hollow part after forming the copper mold body, due to the general phenomenon of electroplating, the length direction or cross section of the casting hollow part, for example, in the case of a polygonal one, It was found that deviations in film thickness occurred at the corners and sides, causing problems in improving the dimensional accuracy of the mold as well as in improving durability.

In addition, when it is necessary to control the thickness of the nickel plating layer according to the durability of the mold, thick plating is difficult when using the above method. It turned out to be almost impossible because it appears so clearly.

The inventors of the present invention have found that the above-mentioned problems can be solved by manufacturing a mold by applying electroforming technology.

In other words, by applying nickel plating or nickel alloy plating to the surface of the mother mold, the dimensional accuracy of the casting hollow part of the copper mold body that is formed in the subsequent stage is improved by the molding accuracy of the mother mold. This can solve the reason why the dimensional accuracy cannot be improved by the electrodeposition of the nickel plating layer in the method described above.

Also, regarding the problem of controlling the thickness of the nickel plating layer, in the case of the present invention, deviations in film thickness when applying nickel dimension or nickel alloy plating to the mother mold do not affect the inner dimensional accuracy of the copper mold body. Since it is completely unrelated, thick plating is possible, and the film thickness can be freely selected depending on the need.

If the deviation in the film thickness of nickel or nickel alloy plating is such that it causes problems in the cooling temperature distribution in the case of cooling, apart from the internal dimensional accuracy of the copper mold body, or if the deviation in the film thickness of nickel plating or nickel alloy plating If the surface condition of the gold plating is poor and it is thought that it will cause problems with the adhesion of the copper plating later, apply nickel plating or nickel alloy plating and then perform mechanical processing to equalize the film thickness and adjust the surface condition. Is it possible to do this?

Furthermore, since the internal dimensional accuracy of the copper mold body made by the method of the present invention is excellent, the friction caused by oscillation when pulling out the slab that is buttoned from the casting hollow part is reduced, and the life of the mold can be extended. .

After applying nickel or nickel alloy plating to the required thickness on the surface of the mother mold, applying copper plating to the required thickness for the mold body on this nickel plating or nickel alloy plating layer, and then, A desired mold can be manufactured by pulling out the matrix or chemically dissolving the matrix.

The adhesion between the nickel plating or nickel alloy plating layer and the copper plating layer can be improved if appropriate treatment is performed before copper plating or if copper plating is performed with sufficient care.

It is well known that in order to further improve the adhesion, a thin diffusion layer is provided by performing appropriate heat treatment.

The master mold used in the example was a stainless steel round bar (size 20φ x 2501 mm) with a taper angle of 0.1° and a mirror-polished bushing surface, on which nickel plating was applied to a thickness of 2mm, and copper plating was further applied to a thickness of 4mmπ. After that, the outer surface of the copper plating was machined to adjust the outer dimensions of the casting mold, and then the mother mold was pulled out and a pipe-shaped mold was made as a prototype.

In addition to nickel plating, nickel-phosphorus, nickel-iron,
Alloy plating such as nickel-chromium or nickel-iron-chromium is possible and has good wear resistance, but for example, when nickel-iron-chromium alloy plating is applied, a strong passive film is created on the surface and the nickel-iron - Before applying copper plating, perform a flushing treatment with a nickel chloride bath or ferrous chloride bath, and then apply a few microns of nickel or iron plating to prevent the adhesion between the chromium alloy plating layer and the copper plating layer. A product with good adhesion to copper plating was obtained.

Copper plating on nickel plating was performed directly on the nickel base using a copper sulfate bath to obtain a copper plating film with good adhesion.

However, for those that have been flushed with ferrous chloride, it is preferable to apply a thin layer of copper plating in a copper bronze bath or a pyrophosphoric acid bath, followed by sulfuric acid steel plating.

In addition, when dissolving the matrix chemically, use an aluminum pipe as the base material, perform zinc substitution in a zincate bath as a pretreatment, then apply nickel residue or nickel alloy plating on top of it, and then copper plating. After plating was completed and the external dimensions were adjusted by machining, the aluminum matrix was dissolved in a caustic soda solution and the zinc-substituted film was further dissolved in hydrochloric acid.

Claims (1)

[Claims] 1. Apply nickel plating or nickel alloy plating to the thickness required for the life of the mold on the surface of the mother mold, and apply copper plating to the thickness required for the mold body on this nickel or nickel alloy plating layer. A method for manufacturing a continuous casting mold, characterized in that the mold is manufactured by subsequently pulling out the mother mold and releasing the mold, or by chemically dissolving the mother mold.