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:
Sep. 22, 2015
Filed:
Sep. 16, 2011
Hiroyuki Kawata, Tokyo, JP;
Naoki Maruyama, Tokyo, JP;
Akinobu Murasato, Tokyo, JP;
Naoki Yoshinaga, Tokyo, JP;
Chisato Wakabayashi, Tokyo, JP;
Noriyuki Suzuki, Tokyo, JP;
Hiroyuki Kawata, Tokyo, JP;
Naoki Maruyama, Tokyo, JP;
Akinobu Murasato, Tokyo, JP;
Naoki Yoshinaga, Tokyo, JP;
Chisato Wakabayashi, Tokyo, JP;
Noriyuki Suzuki, Tokyo, JP;
NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;
Abstract
This high-strength steel sheet includes by mass percentage: 0.05 to 0.4% of C; 0.1 to 2.5% of Si; 1.0 to 3.5% of Mn; 0.001 to 0.03% of P; 0.0001 to 0.01% of S; 0.001 to 2.5% of Al; 0.0001 to 0.01% of N; 0.0001 to 0.008% of O; and a remainder composed of iron and inevitable impurities, wherein a steel sheet structure contains by volume fraction 10 to 50% of a ferrite phase, 10 to 50% of a tempered martensite phase, and a remaining hard phase, wherein a 98% hardness is 1.5 or more times as high as a 2% hardness in a range from ⅛ to ⅜ of a thickness of the steel sheet, wherein a kurtosis K* of the hardness distribution between the 2% hardness and the 98% hardness is −1.2 to −0.4, and wherein an average crystal grain size in the steel sheet structure is 10 μm or less.