Soft stainless steel sheet excellent in workability

US6723181B2 · kind B2 · utility

Assignee

• Nisshin Steel Co., Ltd. · JP

Inventors

• Hanji Ishikawa · Amagasaki, JP
• Masato Otsuka · Tokyo, JP
• Satoshi Suzuki · Moriyama, JP
• Hideki Tanaka · Kadoma, JP
• Junichi Katsuki · Yamaguchi, JP
• Takashi Yamauchi · Tokyo, JP
• Naoto Hiramatsu · Nanyo, JP

Key dates

• Filing date: Apr 11, 2002
• Grant date: Apr 20, 2004
• Expiry date: Apr 28, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D8/0473
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A new soft stainless steel sheet has an austenite-stability index Md30 controlled in a range of −120 to −10 and a stacking fault formability index SFI controlled not less than 30, and involves precipitates whose Cu concentration is controlled not more than 1.0%, so as to maintain concentration of dissolved Cu at 1-5%. The stainless steel sheet preferably contains up to 0.06%(C+N), up to 2.0% Si, up to 5% Mn, 15-20% Cr, 5-9% Ni, 1.0-4.0% Cu, up to 0.003% Al, up to 0.005% S, and optionally one or more of up to 0.5% Ti, up to 0.5% Nb, up to 0.5% Zr, up to 0.5% V, up to 3.0% Mo, up to 0.03% B, up to 0.02% REM (rare earth metals) and up to 0.03% Ca. The stainless steel sheet can be plastically deformed to an objective shape without any cracks even at a part heavily-worked part by multi-stage deep drawing or compression deforming.Md30(° C.)=551−462(C+N)−9.2Si−8.1Mn−29(Ni+Cu)−13.7Cr−18.5Mo SFI(mJ/m2)=2.2Ni+6Cu−1.1Cr−13Si−1.2Mn+32.