Method for producing edged tools
AssigneeKabushiki Kaisha Toyota Chuo Kenkyusho
InventorsTohru Arai, Yoshihiko Sugimoto
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Abstract
A method for producing an edged tool which has an excellent cutting ability and durability, which comprises immersing an edged-tool material in a molten-salt bath containing a carbide-forming element, such as a Va Group element, titanium, chromium or manganese, to form a carbide layer on the surface of the edged-tool material; heating the edged-tool material to a temperature not lower than the austenite-transformation temperature of the material in a non-oxidizing gas atmosphere for a predetermined period of time; and rapidly cooling the heated material to harden it. According to the improved method of the present invention, the edged tool (having an excellent cutting ability and durability) is produced without grinding the formed carbide layer on the surface thereof.
Claims13
A method for producing an edged tool without the need to grind a carbide layer, comprising the steps of:
- (a) immersing tool material with a cutting edge in a molten-salt bath comprising molten boric acid or borate and a carbide-forming element (to form a carbide layer on the surface of said tool material, said tool material being made of ferrous alloy containing at least 0.4 percent by weight of carbon);
- (b) heating said tool material to a temperature not lower than the austenite-transformation temperature of said material in a non-oxidizing gas atmosphere for a predetermined period of time;
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- (c) rapidly cooling and thus hardening said heated material.
A ferrous-alloy tool containing at least 0.4 percent by weight of carbon and having a non-ground sharp and durable, in-situ formed, carbide-coated edge, the tool having a carbide layer, which does not exceed about 5 microns, on its sharp edge.
An edged tool having excellent cutting ability and durability comprising a sharp cutting edge having a cutting-edge angle of not more than 45.degree. and being made of ferrous alloy containing at least 0.4 percent by weight of carbon, said edged tool having (a) no ground end surface adjacent to said sharp cutting edge and (b) a non ground carbide layer having a thickness of not more than 5 microns both on said sharp cutting edge and on an entire end surface of said edged tool adjacent to said sharp cutting edge.
Dependencies are inferred from the claim text.