Steel used for high-strength automobile wheel with excellent flange elongation and production method thereof

Abstract

The invention discloses a high-strength automobile wheel steel with excellent stretch flangeability and a production method thereof. The chemical composition in steel is by weight percentage: C 0.07%~0.1%, Si0.15%~0.25%, Mn 1.2%~1.4%, P<0.02%, S<0.008%, Als0.02%~0.04%, RE / S=1.8-2.2, wherein the rare earth RE is one or a combination of more than two elements in La, Ce and Nd, the content is 0.007%-0.018%, and the balance is Fe and unavoidable impurities. Heat the continuous casting slab to 1200-1300°C and keep it warm for 2-3 hours; the starting temperature of rough rolling is 1100-1250°C, the finishing rolling temperature is >1000°C; the finishing rolling starting temperature is 950-990°C, and the total reduction ratio is >70 %, the final rolling temperature is 780-840°C; the laminar flow cooling process is adopted, the cooling rate is 25-30°C / s, and the final cooling is 450-500°C for coiling.

Description

technical field [0001] The invention belongs to the technical field of steel manufacturing, is mainly used in the production of steel plates for automobile wheels, and particularly relates to a high-strength hot-rolled steel plate with excellent stretch flangeability, low cost and long fatigue life and a production method thereof. Background technique [0002] In recent years, with the vigorous development of the domestic automobile industry, trucks are developing in the direction of large tonnage, and the corresponding wheels need to bear higher strength and fatigue stress. The harsh service conditions of the wheels require steel plates to have high strength, good ductility and Therefore, high-strength steel cannot be used in the forming of complex wheels, and its application area is narrow, so how to improve the strength of the steel plate without compromising its formability become an urgent problem to be solved at present; [0003] The key process of wheel forming is th...

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Problems solved by technology

[0011] CN101082100A discloses a high-strength steel sheet with excellent stretch flangeability, the steel sheet contains: C: 0.10% to 0.20%, Si: 0.8% to 2.5%, Mn: 1.5% to 2.5%, and Al: 0.01% to 0.10%, and Limit P to less than 0.1%, S to less than 0.002%, and the hole expansion rate of the steel plate is less than 80%, which is not suitable for the production and application of complex wheels

[0012] CN101078089A discloses a high-strength hot-rolled steel sheet with excellent stretch-flangeability and its manufacturing method. The chemical composition of the steel contains: C: 0.03% to 0.10%, Si: 0.2% to 2.0%, Mn: 0.5% to 2.5%, Al : 0.02% to 0.10%, Cr: 0.2% to 1.5%, Mo: 0.1% to 0.5%, the martensitic structure in the steel accounts for more than 80%, and the strength of the disclosed steel grades is above 980MPa. The ratio is below 100%, and the stretch flangeability is extremely poor. The structure and strength of this steel type are not suitable for forming wheels with complex shapes.

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