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.

Date of Patent:
Jul. 14, 2020

Filed:

Aug. 10, 2017
Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Noriaki Kohsaka, Tokyo, JP;

Tatsuya Nakagaito, Tokyo, JP;

Lingling Yang, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C 38/54 (2006.01); C22C 38/50 (2006.01); C22C 38/48 (2006.01); C22C 38/46 (2006.01); C22C 38/44 (2006.01); C22C 38/06 (2006.01); C22C 38/58 (2006.01); C22C 38/02 (2006.01); C22C 38/00 (2006.01); B32B 15/01 (2006.01); C21D 6/00 (2006.01); C21D 9/46 (2006.01); C21D 8/02 (2006.01); C23C 2/06 (2006.01); C22C 38/14 (2006.01); C22C 38/04 (2006.01); C22C 38/60 (2006.01); C21D 6/02 (2006.01); C22C 38/22 (2006.01); C22C 18/00 (2006.01); C22C 38/38 (2006.01); C22C 38/08 (2006.01); C22C 38/12 (2006.01); C22C 38/28 (2006.01); C23C 2/28 (2006.01); C22C 18/04 (2006.01); C23C 2/40 (2006.01); C23C 30/00 (2006.01); C22C 38/26 (2006.01); C22C 38/32 (2006.01); C22C 38/20 (2006.01); C22C 38/40 (2006.01); C22C 38/42 (2006.01); C22C 38/18 (2006.01); C23C 2/04 (2006.01); C22C 38/24 (2006.01); B32B 15/04 (2006.01); B32B 15/18 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); B32B 15/01 (2013.01); B32B 15/011 (2013.01); B32B 15/013 (2013.01); B32B 15/04 (2013.01); B32B 15/043 (2013.01); B32B 15/18 (2013.01); C21D 6/001 (2013.01); C21D 6/002 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 6/02 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 8/0263 (2013.01); C22C 18/00 (2013.01); C22C 18/04 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/008 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/08 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/18 (2013.01); C22C 38/20 (2013.01); C22C 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/38 (2013.01); C22C 38/40 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C22C 38/54 (2013.01); C22C 38/58 (2013.01); C22C 38/60 (2013.01); C23C 2/04 (2013.01); C23C 2/06 (2013.01); C23C 2/28 (2013.01); C23C 2/285 (2013.01); C23C 2/40 (2013.01); C23C 30/00 (2013.01); C23C 30/005 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01); Y10T 428/12792 (2015.01); Y10T 428/12799 (2015.01); Y10T 428/12958 (2015.01); Y10T 428/12965 (2015.01); Y10T 428/12972 (2015.01);
Abstract

Provided are a steel sheet with excellent weldability, and a production method therefor. The steel sheet is characterized by having a specific composition and a metallographic structure containing, in terms of an area ratio, ferrite of 25% or more and 65% or less, martensite having iron-based carbides precipitated in the grains of 35% or more and 75% or less, and the balance structure other than the ferrite and the martensite of 20% or less (including 0%) in total, the average grain diameters of the ferrite and the martensite being respectively 5 μm or lower, the total of concentration of Si and Mn at interface between the ferrite and the martensite being, in terms of an atomic concentration, 5% or more, and having a tensile strength of 900 MPa or higher.


Find Patent Forward Citations

Loading…