EP 3272892 A4 20180124 - HIGH-STRENGTH COLD-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING SAME
Title (en)
HIGH-STRENGTH COLD-ROLLED STEEL SHEET AND METHOD FOR MANUFACTURING SAME
Title (de)
HOCHFESTES KALTGEWALZTES STAHLBLECH UND VERFAHREN ZUR HERSTELLUNG DAVON
Title (fr)
TÔLE D'ACIER LAMINÉE À FROID À HAUTE RÉSISTANCE ET SON PROCÉDÉ DE FABRICATION
Publication
Application
Priority
- JP 2015054283 A 20150318
- JP 2016000778 W 20160216
Abstract (en)
[origin: EP3272892A1] Provided are a high-strength cold-rolled steel sheet having a tensile strength (TS) of 1,300 MPa or higher, a good chemical conversion property, and good formability, and a method for producing the high-strength cold-rolled steel sheet. The high-strength cold-rolled steel sheet contains C: 0.15% or more and 0.22% or less, Si: 1.0% or more and 2.0% or less, Mn: 1.7% or more and 2.5% or less, P: 0.05% or less, S: 0.02% or less, Al: 0.01% or more and 0.05% or less, N: 0.005% or less, O: 0.01% or less, and the balance being iron and unavoidable impurities. The composition satisfies [Si]/[Mn] ‰¥ 0.5 ([Si] represents the Si content, and [Mn] represents the Mn content (% by mass)). The steel sheet has a structure including, in terms of area fraction, 60% or more and less than 100% of tempered martensite, 5% or less (inclusive of 0%) of untransformed austenite, and the balance being ferrite. The ferrite has an average crystal grain size of less than 3.5 µm. Less than 10 particles/100 µm 2 of Si-Mn compound oxide particles having a circle equivalent diameter of 5 µm or less are present on the surface of the steel sheet. The surface of the steel sheet is covered with Si-based oxide at a coverage of 1% or less.
IPC 8 full level
C21D 8/02 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01); C22C 38/10 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/18 (2006.01); C22C 38/60 (2006.01); C23G 1/08 (2006.01)
CPC (source: EP KR US)
C21D 6/001 (2013.01 - EP US); C21D 6/002 (2013.01 - EP US); C21D 6/005 (2013.01 - EP US); C21D 6/008 (2013.01 - EP US); C21D 8/0205 (2013.01 - EP US); C21D 8/0226 (2013.01 - KR); C21D 8/0236 (2013.01 - KR); C21D 8/0247 (2013.01 - EP KR US); C21D 9/46 (2013.01 - EP KR US); C22C 38/00 (2013.01 - EP US); C22C 38/001 (2013.01 - EP US); C22C 38/002 (2013.01 - EP US); C22C 38/005 (2013.01 - EP US); C22C 38/008 (2013.01 - EP US); C22C 38/02 (2013.01 - EP KR US); C22C 38/04 (2013.01 - EP KR US); C22C 38/06 (2013.01 - EP KR US); C22C 38/08 (2013.01 - EP US); C22C 38/10 (2013.01 - EP US); C22C 38/12 (2013.01 - EP US); C22C 38/14 (2013.01 - EP US); C22C 38/16 (2013.01 - EP US); C22C 38/18 (2013.01 - EP US); C22C 38/38 (2013.01 - EP US); C22C 38/60 (2013.01 - EP KR US); C23G 1/00 (2013.01 - EP US); C23G 1/08 (2013.01 - EP KR US); C23G 1/081 (2013.01 - EP US); C21D 8/0226 (2013.01 - EP US); C21D 8/0236 (2013.01 - EP US); C21D 8/0273 (2013.01 - EP US); C21D 2211/001 (2013.01 - EP US); C21D 2211/005 (2013.01 - EP US); C21D 2211/008 (2013.01 - EP KR US)
Citation (search report)
- [Y] EP 2589674 A1 20130508 - JFE STEEL CORP [JP]
- [Y] EP 2612957 A1 20130710 - JFE STEEL CORP [JP]
- See references of WO 2016147549A1
Designated contracting state (EPC)
AL 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 RS SE SI SK SM TR
Designated extension state (EPC)
BA ME
DOCDB simple family (publication)
EP 3272892 A1 20180124; EP 3272892 A4 20180124; EP 3272892 B1 20190828; CN 107429344 A 20171201; JP 6210175 B2 20171011; JP WO2016147549 A1 20170713; KR 101998652 B1 20190710; KR 20170116112 A 20171018; MX 2017011825 A 20171207; US 2018037969 A1 20180208; WO 2016147549 A1 20160922
DOCDB simple family (application)
EP 16764383 A 20160216; CN 201680016385 A 20160216; JP 2016000778 W 20160216; JP 2017506047 A 20160216; KR 20177025309 A 20160216; MX 2017011825 A 20160216; US 201615556448 A 20160216