EP 1676933 A1 20060705 - High strength thin steel sheet having high hydrogen embrittlement resisting property and high workability
Title (en)
High strength thin steel sheet having high hydrogen embrittlement resisting property and high workability
Title (de)
Bearbeitungsfähiges hochfestes dünnes Stahlblech mit hohem Widerstand gegen Wasserstoffversprödung
Title (fr)
Tôle d'acier mince à haute résistance, possedant une résistance à la fragilisation par l'hydrogène et une aptitude au façonnage elevées
Publication
Application
Priority
- JP 2004381243 A 20041228
- JP 2004381244 A 20041228
- JP 2004381245 A 20041228
- JP 2005147357 A 20050519
- JP 2005147358 A 20050519
- JP 2005147359 A 20050519
Abstract (en)
The present invention provides a high strength thin steel sheet that has high hydrogen embrittlement resisting property and high workability. The high strength thin steel sheet having high hydrogen embrittlement resisting property has a metallurgical structure after stretch forming process to elongate 3%, which comprises: (i) 1% or more residual austenite; 80% or more in total of bainitic ferrite and martensite; and 9% or less (may be 0%) in total of ferrite and pearlite in terms of proportion of area to the entire structure, wherein the mean axis ratio (major axis/minor axis) of the residual austenite grains is 5 or higher, or (ii) 1% or more residual austenite in terms of proportion of area to the entire structure; mean axis ratio (major axis/minor axis) of the residual austenite grains is 5 or higher; mean length of minor axes of the residual austenite grains is 1 µ m or less; minimum distance between the residual austenite grains is 1 µ m or less; and the steel has tensile strength of 1180 MPa or higher.
IPC 8 full level
C22C 38/02 (2006.01); C22C 38/04 (2006.01)
CPC (source: EP US)
C22C 38/02 (2013.01 - EP US); C22C 38/04 (2013.01 - EP US); C22C 38/06 (2013.01 - EP US); C22C 38/08 (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); C21D 2211/002 (2013.01 - EP US)
Citation (applicant)
- JP H11293383 A 19991026 - NIPPON STEEL CORP
- JP 2003166035 A 20030613 - NIPPON STEEL CORP
- NISSIN STEEL TECHNICAL REPORT, no. 43, December 1980 (1980-12-01), pages 1 - 10
- NEW DEVELOPMENT IN ELUCIDATION OF DELAYED FRACTURE, January 1997 (1997-01-01)
- NEW DEVELOPMENT IN ELUCIDATION OF DELAYED FRACTURE, January 1997 (1997-01-01)
- TOMOHIKO HOJO: "Hydrogen Embrittlement of High Strength Low Alloy TRIP Steel (Part 1: Hydrogen Absorbing Characteristic and Ductility", THE SOCIETY OF MATERIALS SCIENCE, vol. 8, 2002, pages 17 - 18
Citation (search report)
- [PX] EP 1553202 A1 20050713 - KOBE STEEL LTD [JP], et al
- [A] SUGIMOTO K ET AL: "RETAINED AUSTENITE CHARACTERISTICS AND TENSILE PROPERTIES IN A TRIP TYPE BAINITIC SHEET STEEL", ISIJ INTERNATIONAL, TOKYO, JP, vol. 40, no. 9, 2000, pages 902 - 908, XP009048166
- [A] H.K. YALCI ET AL: "The effect of hydrgen on the bainite transformation", JOURNAL OF MATERIAL SCIENCE, no. 34, 1999, UK, pages 711 - 717, XP002369558
- [A] DATABASE COMPENDEX [online] ENGINEERING INFORMATION, INC., NEW YORK, NY, US; HOJO TOMOHIKO ET AL: "Hydrogen Embrittlement of Ultra High Strength Low Alloy TRIP-aided Steels", XP002369564, Database accession no. E2004208160147 & TETSU TO HAGANE; TETSU-TO-HAGANE/JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN MARCH 2004, vol. 90, no. 3, March 2004 (2004-03-01), pages 177 - 182
Designated contracting state (EPC)
AT DE FR GB
DOCDB simple family (publication)
EP 1676933 A1 20060705; EP 1676933 B1 20150527; CA 2531616 A1 20060628; KR 100886052 B1 20090226; KR 20060076741 A 20060704; US 2006137769 A1 20060629
DOCDB simple family (application)
EP 05028528 A 20051227; CA 2531616 A 20051223; KR 20050131620 A 20051228; US 31718105 A 20051227