The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 18, 1995
Filed:
Jan. 31, 1994
Katsuhisa Yamauchi, Kawasaki, JP;
Hitoshi Misao, Kawasaki, JP;
Tadashi Inoue, Kawasaki, JP;
Tomoyoshi Okita, Kawasaki, JP;
NKK Corporation, Tokyo, JP;
Abstract
A fracture resistant stainless steel sheet comprises: non-metallic inclusions of Al.sub.2 O.sub.3, MnO, and SiO.sub.2 which inevitably exist in stainless steel; the non-metallic inclusions having a composition situated in a region defined by nine points in a phase diagram of a 3-component system of 'Al.sub.2 O.sub.3 -MnO-SiO.sub.2 '; the stainless steel sheet having an 1.0% on-set stress of at least 1520 N/mm.sup.2 (155 kgf/mm.sup.2); the stainless steel sheet having an anisotropic difference of 1.0% on-set stress of 196 N/mm.sup.2 (20 kgf/mm.sup.2) or less; and the stainless steel sheet having a punch test work load of at least 25 kgf.multidot.mm or more. A method for producing a high fracture resistant stainless steel sheet comprises the steps of: preparing a stainless steel strip; applying to the stainless steel strip a process of annealing--pickling --first cold rolling (CR.sub.1)--first intermediate annealing--second cold rolling (CR.sub.2)--second intermediate annealing--third cold rolling (CR.sub.3)--final annealing--fourth cold rolling (CR.sub.4)--low temperature heat treatment.