EP 2327810 B1 20190227 - HIGH-STRENGTH STEEL SHEET AND METHOD FOR PRODUCTION THEREOF
Title (en)
HIGH-STRENGTH STEEL SHEET AND METHOD FOR PRODUCTION THEREOF
Title (de)
HOCHFESTES STAHLBLECH UND HERSTELLUNGSVERFAHREN DAFÜR
Title (fr)
FEUILLE D'ACIER DE RÉSISTANCE ÉLEVÉE ET SON PROCÉDÉ DE FABRICATION
Publication
Application
Priority
- JP 2009065981 W 20090908
- JP 2008232437 A 20080910
Abstract (en)
[origin: EP2327810A1] A high strength steel sheet having excellent workability and a tensile strength (TS) of 980 MPa or more is provided. Regarding composition, on a percent by mass basis, C: 0.17% or more, and 0.73% or less, Si: 3.0% or less, Mn: 0.5% or more, and 3.0% or less, P: 0.1% or less, S: 0.07% or less, Al: 3.0% or less, and N: 0.010% or less are included while it is satisfied that Si + Al is 0.7% or more, and the remainder includes Fe and incidental impurities, wherein regarding the steel sheet microstructure, it is specified that the area percentage of a total amount of lower bainite and whole martensite is 10% or more, and 90% or less relative to the whole steel sheet microstructure, the amount of retained austenite is 5% or more, and 50% or less, the area percentage of bainitic ferrite in upper bainite is 5% or more relative to the whole steel sheet microstructure, as-quenched martensite is 75% or less of the total amount of lower bainite and whole martensite, the area percentage of polygonal ferrite is 10% or less (including 0%), and the average amount of C in the above-described retained austenite is 0.70% or more.
IPC 8 full level
C22C 38/06 (2006.01); C21D 9/46 (2006.01); C22C 38/60 (2006.01)
CPC (source: EP KR US)
C21D 1/20 (2013.01 - EP KR US); C21D 8/0247 (2013.01 - EP KR US); C21D 9/46 (2013.01 - EP KR US); C21D 9/48 (2013.01 - EP KR US); C22C 38/001 (2013.01 - KR); C22C 38/002 (2013.01 - KR); C22C 38/005 (2013.01 - KR); C22C 38/02 (2013.01 - EP KR US); C22C 38/04 (2013.01 - EP KR US); C22C 38/06 (2013.01 - EP KR US); C21D 2211/001 (2013.01 - EP US); C21D 2211/002 (2013.01 - EP US); C21D 2211/008 (2013.01 - EP US)
Designated contracting state (EPC)
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR
DOCDB simple family (publication)
EP 2327810 A1 20110601; EP 2327810 A4 20131120; EP 2327810 B1 20190227; CA 2734978 A1 20100318; CA 2734978 C 20160329; CN 102149841 A 20110810; CN 102149841 B 20131120; JP 2010065273 A 20100325; JP 5365112 B2 20131211; KR 101341731 B1 20131216; KR 20110042369 A 20110426; TW 201020329 A 20100601; TW I412609 B 20131021; US 2011162762 A1 20110707; WO 2010030021 A1 20100318
DOCDB simple family (application)
EP 09813166 A 20090908; CA 2734978 A 20090908; CN 200980135575 A 20090908; JP 2008232437 A 20080910; JP 2009065981 W 20090908; KR 20117006084 A 20090908; TW 98130498 A 20090910; US 200913062574 A 20090908