EP 4372119 A1 20240522 - STEEL SHEET, MEMBER, AND MANUFACTURING METHODS THEREFOR
Title (en)
STEEL SHEET, MEMBER, AND MANUFACTURING METHODS THEREFOR
Title (de)
STAHLBLECH, ELEMENT UND HERSTELLUNGSVERFAHREN DAFÜR
Title (fr)
TÔLE D'ACIER, ÉLÉMENT ET PROCÉDÉS DE FABRICATION ASSOCIÉS
Publication
Application
Priority
- JP 2021160629 A 20210930
- JP 2022033946 W 20220909
Abstract (en)
Provided are a steel sheet having high strength, high ductility, excellent stretch flange formability, and good chemical convertibility; a related member; and methods for manufacturing them.The steel sheet has a chemical composition including specific amounts of C, Si, Mn, P, S, sol. Al, and N in mass%. The steel sheet has a specific ratio of the total of polygonal ferrite, upper bainite, retained γ, fresh martensite, tempered martensite, and lower bainite, and a specific ratio of a remaining microstructure. The steel sheet has a specific ratio of the number of fresh martensite grains and retained γ grains having an equivalent circular diameter of less than 0.8 um, and has a specific ratio of the number of fresh martensite grains and retained γ grains having an aspect ratio of 2.0 or more and an equivalent circular diameter of 0.8 um or more.
IPC 8 full level
C22C 38/00 (2006.01); C21D 9/46 (2006.01); C22C 38/06 (2006.01); C22C 38/60 (2006.01)
CPC (source: EP)
C21D 1/20 (2013.01); C21D 1/25 (2013.01); C21D 1/76 (2013.01); C21D 6/005 (2013.01); C21D 8/0236 (2013.01); C21D 8/0273 (2013.01); C21D 9/46 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/008 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/08 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C22C 38/22 (2013.01); C22C 38/32 (2013.01); C22C 38/38 (2013.01); C22C 38/60 (2013.01); C21D 2201/05 (2013.01); C21D 2211/001 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01)
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
Designated validation state (EPC)
KH MA MD TN
DOCDB simple family (publication)
EP 4372119 A1 20240522; CN 117980520 A 20240503; JP 7332062 B1 20230823; JP WO2023053909 A1 20230406; KR 20240051976 A 20240422; WO 2023053909 A1 20230406
DOCDB simple family (application)
EP 22875781 A 20220909; CN 202280064002 A 20220909; JP 2022033946 W 20220909; JP 2022575216 A 20220909; KR 20247008877 A 20220909