Kawasaki Steel Corporation

Nippon Kinzoku Co., Ltd.

Nobuo Ohashi

Minoru Nishida

Motoyuki Konishi

Yukio Inokuchi

Yutaka Ono

Yo Ito

Keiichi Yoshioka

Yoshio Nakazato

Kiyohiko Nohara

Junichi Shimomura

Masatoshi Nakazawa

Tetsuo Miyawaki

Stainless steels for springs having a high strength and an excellent fatigue resistance are produced by heat treating austenitic stainless steels having such a composition that austenite stability index, Md.sub.30. is 0.degree. C. to +80.degree. C. at a final annealing temperature of 750.degree.-1,150.degree. C., subjecting the thus treated steels to a primary working at a temperature from Md.sub.30 to 500.degree. C. at a reduction rate of not less than 20% and then subjecting said steels to a secondary working at a temperature lower than Md.sub.30 at a reduction rate of not less than 30%.

Process for producing stainless steels for spring having a high strength

Martensitic stainless steel having excellent weldability and workability for structural use is obtained by limiting each content of carbon and nitrogen to the low value less than 0.02% and the content of nickel to less than 0.1% and by satisfying the following requirement.

Martensitic stainless steel having excellent weldability and workability

A pretreatment of cold-rolled steel sheet for annealing so as to suppress graphite formation on the surface thereof and nitrogenization during the annealing for recrystallization, by causing an effective amount of sulfur, aluminum, tin, arsenic, lead, antimony, bismuth, selenium, and/or tellurium to exist on the steel sheet surface.

Process of pretreating cold-rolled steel sheet for annealing

Hot-rolled low-carbon steel strip with an excellent press-workability capable of forming a smooth pressed surface consisting essentially of up to 0.12 wt. % carbon, up to 0.01 wt. % nitrogen, up to 0.0094 wt. % boron, and other specific optional ingredients, the B(%)/N(%) ratio being 0.3 to 0.94. The micrograin size number, JIS, of ferrite in the steel strip as hot-rolled is 7 to 9. The steel strip is made by hot-rolling while controlling the temperatures at the entry and delivery ends of a hot-strip finishing mill.

Hot-rolled low-carbon steel strip with an excellent press-workability

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Funabashi, Japan

Nobuo Ohashi