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:
Jun. 11, 2013
Filed:
Feb. 18, 2010
Tetsuji Hoshika, Kakogawa, JP;
Sae Mizuta, Kakogawa, JP;
Yuichi Futamura, Kakogawa, JP;
Masaaki Miura, Kakogawa, JP;
Yukihiro Utsumi, Kakogawa, JP;
Hiroaki Matsumoto, Kakogawa, JP;
Hiroki Ohta, Kakogawa, JP;
Tetsuji Hoshika, Kakogawa, JP;
Sae Mizuta, Kakogawa, JP;
Yuichi Futamura, Kakogawa, JP;
Masaaki Miura, Kakogawa, JP;
Yukihiro Utsumi, Kakogawa, JP;
Hiroaki Matsumoto, Kakogawa, JP;
Hiroki Ohta, Kakogawa, JP;
Kobe Steel, Ltd., Kobe-shi, JP;
Abstract
Disclosed is a cold-rolled steel sheet having a specific steel composition and having a composite steel structure including a ferrite structure and a martensite-containing second phase. In a surface region of the steel sheet from the surface to a depth one-tenth the gage, the number density of n-ary groups of inclusions determined by specific n-th determinations is 120 or less per 100 cmof a rolling plane, in which the distance in steel sheet rolling direction between outermost surfaces of two outermost particles of the group of inclusions is 80 μm or more. Also disclosed is a cold-rolled steel sheet having a specific steel composition and having a steel structure of a martensite single-phase structure. In the surface region, the number density of groups of inclusions, in which the distance between the outermost surfaces is 100 μm or more, is 120 or less per 100 cmof a rolling plane.