Title:
LOW-CARBON LOW-ALLOY Q&P STEEL OR HOT-DIP GALVANIZED Q&P STEEL WITH TENSILE STRENGTH GREATER THAN OR EQUAL TO 1180 MPA, AND MANUFACTURING METHOD THEREFOR
Document Type and Number:
WIPO Patent Application WO/2022/206911
Kind Code:
A1
Abstract:
Provided are a low-carbon low-alloy Q&P steel or hot-dip galvanized Q&P steel with a tensile strength greater than or equal to 1180 MPa, and a manufacturing method therefor. The steel comprises the chemical components by mass percent: C: 0.16-0.23%, Si: 1.1-2.0%, Mn: 1.6-3.0%, P ≤ 0.015%, S ≤ 0.005%, Al: 0.02-0.05%; and the steel can further comprise one or two of Cr, Mo, Ti, Nb and V, and Cr + Mo + Ti + Nb + V ≤ 0.5%, and the balance being Fe and other unavoidable impurities. The manufacturing method comprises the processes of smelting, casting, hot rolling, cold rolling, and a rapid heat treatment or a rapid heat treatment hot dip process. By controlling a rapid heating process, short-time temperature maintaining process and rapid cooling process in a rapid heat treatment process, a recovery process, recrystallization process and austenite phase change process of deformed structures are changed; and by inhibiting the recrystallization of ferrite, a microstructure of an equiaxed fine crystal complex phase is obtained, the final obtained steel has a metallographic structure of a polyphase structure of martensite, residual austenite and ferrite, the grain size is 1-3 μm, the mechanical property is optimized and improved, and the material performance interval range is expanded.
Inventors:
LI JUN (CN)
WANG JIAN (CN)
LIU GENG (CN)
WANG JUNFEI (CN)
MAO ZHANHONG (CN)
DU XIAOFENG (CN)
WANG JIAN (CN)
LIU GENG (CN)
WANG JUNFEI (CN)
MAO ZHANHONG (CN)
DU XIAOFENG (CN)
Application Number:
PCT/CN2022/084518
Publication Date:
October 06, 2022
Filing Date:
March 31, 2022
Export Citation:
Assignee:
BAOSHAN IRON & STEEL (CN)
International Classes:
C22C38/02; C21D1/26; C21D8/02; C22C38/04; C22C38/06; C22C38/12; C22C38/14
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Attorney, Agent or Firm:
SHANGHAI PATENT & TRADEMARK LAW OFFICE, LLC (CN)
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