EP 1350859 A1 20031008 - High-tensile strength hot-rolled steel sheet excellent in elongation properties and stretch flangeability, and producing method thereof
Title (en)
High-tensile strength hot-rolled steel sheet excellent in elongation properties and stretch flangeability, and producing method thereof
Title (de)
Zugfestes warmgewalztes Stahlblech mit ausgezeichneter Bruchdehnung und Streckbördelverformfähigheit und dessen Herstellungsverfahren
Title (fr)
Tôle d'acier laminée à chaud résistant à la traction, ayant une allongement et une déformabilité de bordage par étirage excellente et son procédé de fabrication
Publication
Application
Priority
- JP 2002081451 A 20020322
- JP 2003039099 A 20030218
Abstract (en)
A high-tensile strength hot-rolled steel sheet that satisfies, in addition to TS of 780 MPa or more or furthermore 980 MPa or more, TS X EL ≥ 20000 MPa% and TS x lambda ≥ 82000 MPa%, and a method of producing the same are provided. Specific resolution means are as follows. That is, a high-tensile strength hot-rolled steel sheet including a composition that includes C of 0.04% by mass or more and 0.25% by mass or less; Si of 0.4% by mass or more and 2.0% by mass or less; Mn of 3.0% by mass or less; Al of 0.2% by mass or less; S of 0.007% by mass or less; Ti of 0.08% by mass or more and 0.3% by mass or less; and the balance of Fe and inevitable impurities, in the above, the contents of the C, the Si and the Ti satisfing (Ä%CÜ/12 - Ä%TiÜ/48)/(Ä%SiÜ/28) ≤ 0.4; and a microstructure that includes ferrite; bainite; and retained austenite; in the above a fraction of the ferrite in an entire microstructure is 40% or more and an average grain size of the ferrite is 5 mu m or less; a fraction of the bainite is in the range of 20% to 48% with respect to an entire microstructure; and a fraction of the retained austenite is in the range of 2% to 7% with respect to an entire microstructure is produced.
IPC 1-7
IPC 8 full level
B21B 1/22 (2006.01); B21B 3/00 (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 38/14 (2006.01)
CPC (source: EP KR)
C21D 8/0226 (2013.01 - EP); C21D 8/0263 (2013.01 - EP); C22C 38/00 (2013.01 - KR); C22C 38/02 (2013.01 - EP); C22C 38/04 (2013.01 - EP); C22C 38/14 (2013.01 - EP); C21D 2211/001 (2013.01 - EP); C21D 2211/002 (2013.01 - EP); C21D 2211/005 (2013.01 - EP)
Citation (search report)
- [A] EP 0586704 A1 19940316 - NIPPON STEEL CORP [JP]
- [A] EP 1001041 A1 20000517 - KAWASAKI STEEL CO [JP]
- [A] EP 0945522 A1 19990929 - KAWASAKI STEEL CO [JP]
- [A] PATENT ABSTRACTS OF JAPAN vol. 1997, no. 10 31 October 1997 (1997-10-31)
- [A] PATENT ABSTRACTS OF JAPAN vol. 2000, no. 25 12 April 2001 (2001-04-12)
- [A] PATENT ABSTRACTS OF JAPAN vol. 1999, no. 11 30 September 1999 (1999-09-30)
- [A] DATABASE COMPENDEX [online] ENGINEERING INFORMATION, INC., NEW YORK, NY, US; EVANS P J ET AL: "High strength C-Mn steels for automotive applications", XP002246411, Database accession no. EIX98214145887 & IRONMAKING STEELMAKING;IRONMAKING AND STEELMAKING 1997 INST OF MATERIALS, LONDON, ENGL, vol. 24, no. 5, 1997, pages 361 - 367, XP002246410
Designated contracting state (EPC)
DE FR
DOCDB simple family (publication)
EP 1350859 A1 20031008; EP 1350859 B1 20041229; CN 1296507 C 20070124; CN 1450191 A 20031022; DE 60300242 D1 20050203; DE 60300242 T2 20050602; JP 2004002969 A 20040108; JP 4062118 B2 20080319; KR 100778264 B1 20071122; KR 20030076430 A 20030926
DOCDB simple family (application)
EP 03006195 A 20030319; CN 03107449 A 20030321; DE 60300242 T 20030319; JP 2003039099 A 20030218; KR 20030017697 A 20030321