A cold-rolled steel sheet for automobiles with high strength and high plasticity and production method thereof

Abstract

The invention discloses a high-strength high-plasticity cold-rolled steel plate for automobiles and a production method thereof. The high-strength high-plasticity cold-rolled steel plate comprises, by weight, 0.25-0.35% of C, 0.8-1.2% of Si, 2.0-2.5% of Mn, less than or equal to 0.02% of P, less than or equal to 0.005% of S, 0.5-1.0% of Al, 0.001-0.002% of B and the balance Fe and unavoidable impurities. The production method comprises smelting, continuous casting, hot rolling, pickling, cold rolling and continuous annealing. A continuous annealing heating temperature is in a range of 800-850 DEG C, thermal insulation time is in a range of 150-180s, a cooling rate is greater than or equal to 50 DEG C / s, a quenching temperature is in a range of 250-280 DEG C, a partition temperature is in a range of 350-400 DEG C, partition time is in a range of 300-600s and after partition, the product is cooled to a room temperature at a cooling rate greater than or equal to 50 DEG C / s.

Description

technical field [0001] The invention belongs to the field of cold-rolled automobile steel manufacturing, and relates to a high-strength and high-plasticity cold-rolled steel plate with a tensile strength greater than 980 MPa and an elongation greater than 20% and a production method thereof. Background technique [0002] After more than a century of development, the automobile industry has gradually become a pillar industry of my country's national economy. After entering the 21st century, automobile materials have undergone great changes. From the perspective of the overall development of automobile materials in Europe, the United States, Japan and other countries, due to the requirements of lightweight automobiles, the amount of steel used is decreasing. Powder metals, non-ferrous metals and The use of plastic is increasing. However, in order to improve the safety of the car, active and passive safety measures must be added, which will increase the weight of the car. An ...

AI Technical Summary

Problems solved by technology

[0008] Among the published patents for cold-rolled high-strength steel sheets, very few have a tensile strength above 980 MPa, and there are generally disadvantages such as low elongation, many types of alloying elements, large amounts of additions, high smelting costs, and great difficulty.

For the new Q-P heat treatment process, theoretically, the steel plate needs to be heated above the Ac3 point, the temperature is higher, and the energy consumption is larger

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