Title:
HEAT TREATMENT OF STEEL
Document Type and Number:
Japanese Patent JP3387427
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain sufficient strength to micronize a steel grain size and to increase a charbonitride precipitating to a grain boundary by heating a steel up to the austenite region in an atmosphere containing carbonizing gas, rapidly cooling down to the martensite region subjecting to carbonizing/quenching and heating to the austenite region in an atmosphere containing carbonizing gas and ammonia subjecting to requesting.
SOLUTION: After a steel is heated up to the austenite reign in an atmosphere containing carbonizing gas and ammonia, the steel is rapidly cooled down to the martensite region subjecting to carbnurizing/quenching, further after the steel is heated up to the austentie region in an atmosphere containing carbonizing gas and ammonia, the steel is preferably subjected to a second quench process to requench. The second quench process preferably heats a steel up to 800-850°C, after a steel is heated up to a first heating temp. in an atmosphere of a fixed ammonia concentration in the second quench process, the steel is preferably heated to a second heating temp. in a prescribed temp. lower than first heating temp.
Inventors:
Takeshi Isoya
Ryuichi Uchino
Masahiko Sato
Yoshio Kawano
Ryuichi Uchino
Masahiko Sato
Yoshio Kawano
Application Number:
JP29667198A
Publication Date:
March 17, 2003
Filing Date:
October 19, 1998
Export Citation:
Assignee:
Aisin Seiki Co., Ltd.
International Classes:
C21D1/06; C21D1/78; C21D6/00; C23C8/22; C23C8/28; C23C8/32; C23C8/34; C21D1/18; (IPC1-7): C21D1/06; C21D6/00; C23C8/22; C23C8/28; C23C8/34
Domestic Patent References:
| JP1151155A |
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