EP 2243853 B1 20170405 - HIGH-STRENGTH HOT-ROLLED STEEL SHEET AND PROCESS FOR PRODUCTION THEREOF
Title (en)
HIGH-STRENGTH HOT-ROLLED STEEL SHEET AND PROCESS FOR PRODUCTION THEREOF
Title (de)
HOCHFESTES HEISSGEWALZTES STAHLBLECH UND HERSTELLUNGSVERFAHREN DAFÜR
Title (fr)
TÔLE D'ACIER LAMINÉE À CHAUD DE FORTE RÉSISTANCE ET SON PROCÉDÉ DE PRODUCTION
Publication
Application
Priority
- JP 2009052244 W 20090204
- JP 2008028455 A 20080208
Abstract (en)
[origin: EP2243853A1] There is provided a high-strength hot-rolled steel sheet having a tensile strength (TS) of 540 to 780 MPa, only small variations in strength, and excellent uniformity in strength using a general-purpose Ti-containing steel sheet, which is inexpensive. The high-strength hot-rolled steel sheet includes, on a mass percent basis, 0.05%-0.12% C, 0.5% or less Si, 0.8%-1.8% Mn, 0.030% or less P, 0.01% or less S, 0.005%-0.1% Al, 0.01% or less N, 0.030%-0.080% Ti, and the balance being Fe and incidental impurities. The microstructure have a volume fraction of polygonal ferrite of 70% or more, and the amount of Ti present in a precipitate having a size of less than 20 nm is 50% or more of the value of Ti* calculated using formula (1): Ti* = [Ti] - 48/14 × [N] (1) where [Ti] and [N] represent a Ti content (percent by mass) and a N content (percent by mass), respectively, of the steel sheet.
IPC 8 full level
C22C 38/00 (2006.01); C21D 9/46 (2006.01); C22C 38/14 (2006.01)
CPC (source: EP KR US)
C21D 8/0226 (2013.01 - EP KR US); C21D 8/0263 (2013.01 - EP KR US); C21D 9/46 (2013.01 - EP KR US); C22C 38/04 (2013.01 - EP KR US); C22C 38/06 (2013.01 - EP KR US); C22C 38/14 (2013.01 - EP KR US); C21D 2211/004 (2013.01 - EP KR US); C21D 2211/005 (2013.01 - EP KR 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 TR
DOCDB simple family (publication)
EP 2243853 A1 20101027; EP 2243853 A4 20120425; EP 2243853 B1 20170405; CN 101939459 A 20110105; CN 101939459 B 20120711; JP 2009185361 A 20090820; JP 5194858 B2 20130508; KR 101203018 B1 20121120; KR 20100087239 A 20100803; US 2010319819 A1 20101223; WO 2009099237 A1 20090813
DOCDB simple family (application)
EP 09708321 A 20090204; CN 200980104588 A 20090204; JP 2008028455 A 20080208; JP 2009052244 W 20090204; KR 20107014865 A 20090204; US 86638209 A 20090204