EP 4375389 A1 20240529 - COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREOF
Title (en)
COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREOF
Title (de)
KALTGEWALZTES STAHLBLECH UND HERSTELLUNGSVERFAHREN DAFÜR
Title (fr)
TÔLE D'ACIER LAMINÉE À FROID ET SON PROCÉDÉ DE FABRICATION
Publication
Application
Priority
- JP 2021120895 A 20210721
- JP 2022027703 W 20220714
Abstract (en)
This cold-rolled steel sheet has a predetermined chemical composition, in which, in a case where a range of 1/8 to 3/8 of a sheet thickness from a surface in a sheet thickness direction is defined as a t/4 portion and a range of 20 µm from the surface in the sheet thickness direction is defined as a surface layer portion, a microstructure at the t/4 portion includes, by volume percentage, 0% or more and 10.0% or less of retained austenite and 90.0% or more and 100% or less of one or two of martensite and tempered martensite, a ratio of a dislocation density of the surface layer portion to a dislocation density of the t/4 portion is 0.80 or more, a ratio of a hardness of the surface layer portion to a hardness of the t/4 portion is 0.90 or more, and a tensile strength of the cold-rolled steel sheet is 1,310 MPa or more.
IPC 8 full level
C22C 38/00 (2006.01); C21D 9/46 (2006.01); C22C 38/60 (2006.01)
CPC (source: EP KR)
C21D 1/19 (2013.01 - EP); C21D 1/25 (2013.01 - EP); C21D 1/26 (2013.01 - EP); C21D 8/0205 (2013.01 - EP); C21D 8/0226 (2013.01 - KR); C21D 8/0236 (2013.01 - EP KR); C21D 8/0242 (2013.01 - EP); C21D 8/0263 (2013.01 - EP KR); C21D 8/0273 (2013.01 - EP); C21D 9/46 (2013.01 - EP KR); C22C 38/001 (2013.01 - KR); C22C 38/002 (2013.01 - EP); C22C 38/005 (2013.01 - EP); C22C 38/008 (2013.01 - EP KR); C22C 38/02 (2013.01 - EP); C22C 38/04 (2013.01 - EP); C22C 38/06 (2013.01 - EP KR); C22C 38/08 (2013.01 - EP); C22C 38/10 (2013.01 - EP); C22C 38/12 (2013.01 - EP); C22C 38/14 (2013.01 - EP); C22C 38/16 (2013.01 - EP); C22C 38/20 (2013.01 - EP); C22C 38/22 (2013.01 - EP); C22C 38/30 (2013.01 - EP); C22C 38/32 (2013.01 - EP); C22C 38/38 (2013.01 - EP); C22C 38/42 (2013.01 - KR); C22C 38/44 (2013.01 - KR); C22C 38/46 (2013.01 - KR); C22C 38/48 (2013.01 - EP KR); C22C 38/50 (2013.01 - KR); C22C 38/52 (2013.01 - KR); C22C 38/54 (2013.01 - KR); C22C 38/58 (2013.01 - KR); C22C 38/60 (2013.01 - EP); C23C 2/02 (2013.01 - EP); C23C 2/04 (2013.01 - KR); C23C 2/06 (2013.01 - EP); C23C 2/12 (2013.01 - EP); C23C 2/26 (2013.01 - EP); C23C 2/28 (2013.01 - EP); C23C 2/40 (2013.01 - EP); C21D 2211/001 (2013.01 - EP KR); C21D 2211/008 (2013.01 - EP KR)
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 4375389 A1 20240529; CN 117751204 A 20240322; JP WO2023002910 A1 20230126; KR 20240023431 A 20240221; MX 2024000460 A 20240129; WO 2023002910 A1 20230126
DOCDB simple family (application)
EP 22845844 A 20220714; CN 202280049812 A 20220714; JP 2022027703 W 20220714; JP 2023536714 A 20220714; KR 20247001677 A 20220714; MX 2024000460 A 20220714