Method for forming a carbide layer on the surface of a ferrous alloy article or a cemented carbide article
AssigneeKabushiki Kaisha Toyota Chuo Kenkyusho
InventorsTohru Arai, Hironori Fujita, Yasuo Takada
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Abstract
A method for forming a carbide layer on the surface of a carbon-containing ferrous alloy article or a cemented carbide article in a molten treating bath. The bath is prepared by introducing 5 to 20% by weight of alumina into molten boric acid or borate bath and a carbide-forming element dissolved therein. By employing the treating bath of this invention, the life of the bath can be remarkably improved, and no sintered substance of undissolved carbide-forming element is produced in the treating bath. Further, it is possible to reduce markedly the corrosion of the article and of the vessel holding the bath.
Claims20
A method for forming a carbide layer on the surface of a carbon-containing ferrous alloy article or a cemented carbide article, comprising the steps of:
- (a) preparing a treating bath comprising molten boric acid or borate, a carbide-forming element dissolved therein and 5 to 20% by weight, based on the whole weight of the bath, of alumina;
- (b) keeping said treating bath at a temperature within the range from 1050.degree. C. to a temperature lower than the melting point of the article to be treated;
- (c) immersing the article into the molten treating bath;
- (d) maintaining said article in said molten treating bath to form a carbide layer of said carbide-forming element on the surface of said article;
- and
- (e) removing said article from said molten treating bath.
A treating material for forming a carbide layer on the surface of a carbon-containing ferrous alloy article or a cemented carbide article which is composed of boric acid or a borate, a carbide-forming element and from 5 to 20% by weight, based on the whole weight of the treating material, of alumina.
Dependencies are inferred from the claim text.