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1. (WO2018220598) STEEL SHEET FOR MANUFACTURING PRESS HARDENED PARTS, PRESS HARDENED PART HAVING A COMBINATION OF HIGH STRENGTH AND CRASH DUCTILITY, AND MANUFACTURING METHODS THEREOF

Pub. No.:    WO/2018/220598    International Application No.:    PCT/IB2018/053950
Publication Date: Fri Dec 07 00:59:59 CET 2018 International Filing Date: Sat Jun 02 01:59:59 CEST 2018
IPC: C21D 8/02
C21D 8/04
C21D 1/19
C21D 1/673
C22C 38/02
C22C 38/04
C22C 38/06
C22C 38/12
C22C 38/14
C22C 38/22
C22C 38/28
C22C 38/32
C22C 38/38
B23K 35/30
C21D 9/46
C21D 9/48
C22C 38/00
C22C 38/44
C22C 38/48
C22C 38/50
C22C 38/54
C22C 38/58
B21D 22/02
B21D 22/20
Applicants: ARCELORMITTAL
Inventors: BEAUVAIS, Martin
DUMONT, Alice
GIBOT, Alexandre
PERLADE, Astrid
ZHU, Kangying
Title: STEEL SHEET FOR MANUFACTURING PRESS HARDENED PARTS, PRESS HARDENED PART HAVING A COMBINATION OF HIGH STRENGTH AND CRASH DUCTILITY, AND MANUFACTURING METHODS THEREOF
Abstract:
A steel sheet for the manufacture of a press hardened part, having a composition comprising: 0.15%≤ C ≤ 0.22%, 3.5%≤ Mn < 4.2%, 0.001 %≤ Si ≤ 1.5%, 0.020%≤ Al ≤ 0.9%, 0.001 % ≤ Cr ≤ 1 %, 0.001 % ≤ Mo ≤ 0.3%, 0.001 % ≤ Ti ≤ 0.040%, 0.0003% ≤ B ≤ 0.004%, 0.001 %≤ Nb ≤ 0.060%, 0.001 %≤ N ≤ 0.009%, 0.0005% ≤ S ≤ 0.003%, 0.001 % ≤ P ≤ 0.020%, the microstructure consisting of less than 50% ferrite, 1 % to 20% retained austenite, cementite, such that the surface density of cementite particles larger than 60 nm is lower than 10∧7/mm2, the complement consisting of bainite and/or martensite, the retained austenite having an average Mn content of at least 1.1 *Mn%. Press-hardened steel part obtained by hot forming the steel sheet, and manufacturing methods thereof.