EP 1458896 A1 20040922 - HIGH STRENGTH COLD ROLLED STEEL SHEET WITH SUPERIOR FORMABILITY AND WELDABILITY, AND MANUFACTURING METHOD THEREFOR
Title (en)
HIGH STRENGTH COLD ROLLED STEEL SHEET WITH SUPERIOR FORMABILITY AND WELDABILITY, AND MANUFACTURING METHOD THEREFOR
Title (de)
HOCHFESTES KALTGEWALZTES STAHLBLECH MIT ÜBERLEGENER FORMBARKEIT UND SCHWEISSBARKEIT UND HERSTELLUNGSVERFAHREN DAFÜR
Title (fr)
FEUILLE D'ACIER DE HAUTE RESISTANCE LAMINEE A FROID DOTEE DE CARACTERISTIQUES SUPERIEURES DE FORMABILITE ET DE SOUDABILITE, ET PROCEDE DE FABRICATION
Publication
Application
Priority
- KR 0201167 W 20020620
- KR 20010085539 A 20011227
Abstract (en)
[origin: WO03056041A1] A high strength cold-rolled steel sheet, which simultaneously provides a tensile strength of 70 to 90 kgf/mm2 grade and is easily formed, thereby increasing an impact energy absorption in case of collision and enhancing the safety of automobiles, and its manufacturing method. The high strength cold-rolled steel sheet with excellent formability and weldability, comprises, in terms of percent by weight, 0.15 to 0.25% C, 0.5 to 1.5% Si, 1.0 to 2.0% Mn, 0.25% or less P, 0.020% or less S, 0.015 to 0.050% Al, 0.008 to 0.026% N, balance Fe and incidental impurities while satisfying a condition of 1.2<= Si[%]+50/8P[%]<= 2.0. The method comprises the steps of hot rolling a steel having the above composition using a conventional method, cold rolling the hot-rolled steel sheet using a conventional method to form a cold-rolled steel sheet; continuous annealing the cold-rolled steel sheet at a temperature range satisfying a condition of 563+651C[%]+42Si[%]+18Mn[%]<= annealing temperature [°C]<= 850; and quenching the continuous annealed steel sheet at a rate of 20 to 100°C/s to an austempering initiating temperature ranging from 400 to 450°C and then cooling to a temperature ranging from 350 to 400°C .
IPC 1-7
IPC 8 full level
B21B 3/00 (2006.01); C21D 1/20 (2006.01); 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)
CPC (source: EP KR US)
C21D 1/20 (2013.01 - EP US); C21D 8/02 (2013.01 - KR); C21D 8/0273 (2013.01 - EP US); C22C 38/02 (2013.01 - EP US); C22C 38/04 (2013.01 - EP US); C21D 8/0226 (2013.01 - EP US); C21D 8/0236 (2013.01 - EP US); C21D 8/0278 (2013.01 - EP US); C21D 2211/001 (2013.01 - EP US); C21D 2211/002 (2013.01 - EP US)
Designated contracting state (EPC)
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
DOCDB simple family (publication)
WO 03056041 A1 20030710; EP 1458896 A1 20040922; EP 1458896 A4 20041229; JP 2005513271 A 20050512; JP 3895728 B2 20070322; KR 100554753 B1 20060224; KR 20030055524 A 20030704; US 2004238083 A1 20041202
DOCDB simple family (application)
KR 0201167 W 20020620; EP 02741471 A 20020620; JP 2003556557 A 20020620; KR 20010085539 A 20011227; US 48135403 A 20031218