Baoshan Iron & Steel Co., Ltd.

Ana Yang

Wei Wang

Huanrong Wang

Fengming Song

Jiansu Zhang

Zigang Li

Gang Liu

Xiaoping Hu

Donghui Wen

Jianye Li

Xiaozhen Yang

Disclosed are a high-strength and high-toughness steel plate with an 800 MPa grade tensile strength and a method for manufacturing the same, the chemical composition of the steel plate in weight percentage being: C: 0.15-0.25%, Si: 1.0-2.0%, Mn: 1.2-2.0%, P&#x2264;0.015%, S&#x2264;0.005%, Al: 0.5-1.0%, N: &#x2264;0.006%, Nb: 0.02-0.06%, O&#x2264;0.003%, and the balance being Fe and other inevitable impurities, and 1.5%&#x2264;Si+Al&#x2264;2.5%. By adopting an isothermal heat treatment a high-strength and high-toughness steel plate with an 800 MPa grade tensile strength, which has a microstructure mainly including bainite ferrite and residual austenite, is obtained impact energy.

High-strength high-tenacity steel plate with tensile strength of 800 MPa and production method therefor

A 980 MPa-grade hot-rolled dual-phase steel and a manufacturing method therefor. The chemical components of the steel comprise, in percentage by weight, 0.10%-0.20% of C, 0.8%-2.0% of Si, 1.0%-2.0% of Mn, 0-0.02% of P, 0-0.005% of S, 0-0.003% of O, 0.02%-0.06% of Al, 0-0.006% of N, 0.01%-0.06% of Nb, 0.01%-0.05% of Ti, and the balance of Fe and inevitable impurities. In addition, the components need to meet the following relation: 0.05%&#x2264;Nb+Ti&#x2264;0.10. The microstructure of the steel is made of ferrite and martensite. The average grain size of the ferrite is 5-10 &#x3bc;m, and the equivalent grain size of the martensite is 15-20 &#x3bc;m. The yield strength of the steel is greater than or equal to 500 MPa, the tensile strength of the steel is greater than or equal to 980 MPa, and the ductility Ais greater than or equal to 12%; the steel has excellent strength, ductility and tenacity matching and a relatively low yield ratio, and can be applied to parts requiring good formability, high strength and reduced thickness, such as wheels.

980 MPa-grade hot-rolled dual-phase steel and manufacturing method therefor

A 980 MPa-grade hot-rolled ferrite bainite dual-phase steel and a manufacturing method therefor. The chemical components of the steel comprise, in percentage by weight, 0.15-0.30% of C, 0.8-2.0% of Si, 1.0-2.0% of Mn, 0-0.02% of P, 0-0.005% of S, 0-0.003% of O, 0.5-1.0% of Al, 0-0.006% of N, 0.01-0.06% of Nb, 0.01-0.05% of Ti, and the balance of Fe and inevitable impurities. In addition, the chemical components meet the following relations: 0.05%&#x2264;Nb+Ti&#x2264;0.10%, and 2.5&#x2264;Al/C&#x2264;5.0. The microstructure of the steel is made of ferrite and bainite. The average grain size of the ferrite is 5-10 &#x3bc;m, and the equivalent grain size of the bainite is less than or equal to 20 &#x3bc;m. The yield strength of the steel is greater than or equal to 600 MPa, the tensile strength of the steel is greater than or equal to 980 Mpa, and the ductility is greater than or equal to 15%.

980 MPa-grade hot-rolled ferritic bainite dual-phase steel and manufacturing method therefor

Disclosed is provided a low yield ratio and superhigh-strength hot-rolled Q&P steel and a method for manufacturing the same, having the following chemical composition in weight percentage: C: 0.2-0.3%, Si: 1.0-2.0%, Mn: 1.5-2.5%, P: &#x2264;0.015%, S: &#x2264;0.005%, Al: 0.5-1.0%, N: &#x2264;0.006%, Nb: 0.02-0.06%, Ti: &#x2264;0.03%, O: &#x2264;0.003%, and the balance being Fe and inevitable impurities. The manufacture method comprises a stepped cooling process to finally obtain the steel with a three-phase structure containing a certain volume fraction of proeutectoid ferrite; martensite; and residual austenite, and having an excellent comprehensive performance with a yield strength of &#x2265;600 MPa, a tensile strength of &#x2265;1300 MPa, a good elongation, and a low yield ratio. The obtained Q&P steel also shows an excellent match of high plasticity suitable for easy deformabilities and wear-resistances.

Low-yield-ratio ultra-high-strength hot-rolled QandP steel and production method therefor

A high-strength steel having a yield strength at a level of 800 MPa and a method of manufacturing the same, with the components and amounts thereof by weight percentage being: C: 0.06-0.14%, Si: 0.1-0.30%, Mn: 0.8-1.60%, Cr: 0.2-0.70%, Mo: 0.1-0.40%, Ni: 0-0.30%, Nb: 0.01-0.030%, Ti: 0.01-0.030%, V: 0.01-0.05%, B: 0.0005-0.0030%, Al: 0.02-0.06%, Ca: 0.001-0.004%, N: 0.002-0.005%, P&#x2264;0.02%, S&#x2264;0.01%, O&#x2264;0.008%, the balance of Fe and unavoidable impurities; wherein the above elements meet the following relationships: 0.40%&#x3c;Ceq&#x3c;0.50%, Ceq=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15; 0.7%&#x2264;Mo+0.8Ni+0.4Cr+6V&#x2264;1.1%; 3.7&#x2264;Ti/N&#x2264;7.0; 1.0&#x2264;Ca/S&#x2264;3.0.

High-strength steel with yield strength of 800 MPa and production method therefor

The invention provides a highly corrosion-resistant, high strength, Al-containing weathering steel plate, wherein the chemical composition comprises in weight percentages (wt %) of: C: 0.02-0.07%, Si: 0.2-1.0%, Mn: 0.2-2.2%, P&#x2264;0.01%, S&#x2264;0.006%, Cu: 0.2-0.5%, Cr: 0.5-3.5%, Ni: 0.2-1.2%, Al: 0.4-4.0%, N&#x2264;0.005%; selectively added one or more of Nb: 0.01-0.06%, Ti: 0.01-0.10%, V: 0.02-0.10%; the balance of Fe and unavoidable impurities, wherein Al/Cr is 0.5-8.0. The steel plate has a yield strength of 350-500 MPa, an elongation of 20% or more, a relative corrosion rate of 27% or less and a good impact toughness and a low yield ratio. The present application also provides a method for manufacturing the weathering steel plate.

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Shanghai, China

Ana Yang