Baoshan Iron & Steel Co., Ltd.

Hanlong Zhang

Yulong Zhang

Li Ping Wang

Cheng Wang

Li Wang

Xinyan Jin

Yiqiang Sun

Shuize Wang

Xinping Mao

Disclosed are a low-cost ultra-high-strength multiphase steel plate/steel strip and its manufacturing method. Said steel plate/steel strip comprises the following components in percentage by weight: 0.03 to 0.07% of C, 0.1 to 0.5% of Si, 1.3 to 1.9% of Mn, less than or equal to 0.02% of P, less than or equal to 0.01% of S, 0.01 to 0.05% of Al, 0.2 to 0.5% of Cr, 0.07 to 0.14% of Ti, less than 0.03% of (Ni+Nb+Mo+V), and the balance being Fe and other inevitable impurities; and Mn+1.5Cr+5 (Ti+Al+Cu)+10(Mo+Ni)+20(Nb+V)<3.0; Mn+2Cr+4Ti+4Nb+4V+4Mo—Si/3+2C≤3.0. The steel plate is mainly used for the manufacturing of automotive chassis and suspension system parts.

Low-carbon low-cost ultra-high-strength multiphase steel plate/steel strip and manufacturing method therefor

An ultra-high-strength hot-rolled steel plate and steel strip having good fatigue and reaming properties and a manufacturing method therefor. The weight percentages of the components of the steel plate and the steel strip are: C: 0.07-0.14%, Si: 0.1-0.4%, Mn: 1.55-2.00%, P&#x2264;0.015%, S&#x2264;0.004%, Al: 0.01-0.05%, N&#x2264;0.005%, Cr: 0.15-0.50%, V: 0.1-0.35%, Nb: 0.01%-0.06%, Mo: 0.15-0.50%, Ti&#x2264;0.02%, and the balance of Fe and unavoidable impurities. Such components need to meet: 1.0&#x2264;[(Cr/52)/(C/4)+(Nb/93+Ti/48+V/51+Mo/96)/(C/12)]&#x2264;1.6. The tensile strength of the ultrahigh-strength hot-rolled steel plate and steel strip is &#x2265;780 MPa, the yield strength thereof is &#x2265;660 MPa, the tensile fatigue limit (10 million cycles) FL thereof is &#x2265;570 MPa, or the fatigue limit to tensile strength FL/Rm thereof is &#x2265;0.72. The reaming rate meets: if an original hole is a punched hole, the reaming rate thereof is &#x3e;85%; and if the original hole is a reamed hole, the reaming rate thereof is &#x3e;120%.

Ultrahigh-strength hot-rolled steel sheet and steel strip having good fatigue and reaming properties and manufacturing method therefor

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Shanghai, China

Hanlong Zhang