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:
Nov. 24, 2015
Filed:
Feb. 27, 2012
Toshio Murakami, Kobe, JP;
Elijah Kakiuchi, Kobe, JP;
Hideo Hata, Kobe, JP;
Tatsuya Asai, Kakogawa, JP;
Naoki Mizuta, Kakogawa, JP;
Toshio Murakami, Kobe, JP;
Elijah Kakiuchi, Kobe, JP;
Hideo Hata, Kobe, JP;
Tatsuya Asai, Kakogawa, JP;
Naoki Mizuta, Kakogawa, JP;
Kobe Steel, Ltd., Kobe, JP;
Abstract
This high-strength steel sheet has a component composition containing, in mass %, 0.02 to 0.3% C, 1 to 3% Si, 1.8 to 3% Mn, 0.1% or less P, 0.01% or less S, 0.001 to 0.1% Al, and 0.002 to 0.03% N, the remainder being iron and impurities. The high-strength steel sheet has a structure containing, in terms of area ratio relative to the entire structure, each of the following phases: 50 to 85% bainitic ferrite; 3% or more retained austenite (γ); 10 to 45% martensite and the aforementioned retained austenite (γ); and 5 to 40% ferrite. The ratio between the Mn concentration (Mn) in the retained austenite (γ) and the average Mn concentration (Mn) in the entire structure is 1.2 or more (Mn/ Mn) based on the Mn concentration distribution obtained by means of EPMA line analysis. As a consequence, the high-strength steel sheet exhibits strength of 980 MPa or more and exerts excellent deep drawability.