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1. (WO2018076965) COLD-ROLLED HIGH-STRENGTH STEEL HAVING TENSILE STRENGTH OF NOT LESS THAN 1500 MPA AND EXCELLENT FORMABILITY, AND MANUFACTURING METHOD THEREFOR

Pub. No.:    WO/2018/076965    International Application No.:    PCT/CN2017/102384
Publication Date: Fri May 04 01:59:59 CEST 2018 International Filing Date: Thu Sep 21 01:59:59 CEST 2017
IPC: C22C 38/02
C22C 38/04
C22C 38/06
C22C 38/18
C22C 38/12
C21D 1/26
C21D 8/02
Applicants: BAOSHAN IRON & STEEL CO., LTD.
宝山钢铁股份有限公司
Inventors: ZHOU, Shu
周澍
ZHONG, Yong
钟勇
WANG, Li
王利
Title: COLD-ROLLED HIGH-STRENGTH STEEL HAVING TENSILE STRENGTH OF NOT LESS THAN 1500 MPA AND EXCELLENT FORMABILITY, AND MANUFACTURING METHOD THEREFOR
Abstract:
Provided is a cold-rolled high-strength steel having a tensile strength of not less than 1500 MPa and an excellent formability, the chemical elements thereof having the following mass percent ratios: 0.25% - 0.40% of C, 1.50% - 2.50% of Si, 2.0% - 3.0% of Mn, 0.03% - 0.06% of Al, P ≤ 0.02%, S ≤ 0.01%, N ≤ 0.01% and at least one of 0.1% - 1.0% of Cr and 0.1% - 0.5% of Mo, with the balance being Fe and other unavoidable impurities. The microstructure of the cold-rolled high-strength steel has 5% - 20% of residual austenite and 70% - 90% of martensite, and the carbon concentration ratio of the residual austenite to the martensite is greater than 3.5 and less than 15. A cold-rolled high-strength steel sheet has a high strength and an excellent formability through a rational ingredient design and microstructure control.