800 MPa grade high-strength plastic product Q&P steel plate and preparation method thereof

Abstract

The invention discloses a 800 MPa grade high-strength plastic product Q&P steel plate and a preparation method thereof, and belongs to the technical field of cold-rolled automobile steel production. The steel plate comprises the following chemical components of, in percentage by weight, 0.38%-0.42% of C, 0.10%-0.30% of Si, 0.80%-1.20% of Mn, 2.80%-3.20% of Al, less than or equal to 0.020% of P, less than or equal to 0.0030% of S, less than or equal to 0.0060% of N, the balance Fe and inevitable impurity elements. The preparation method comprises the following steps of smelting; continuous casting; hot rolling; acid pickling; cold rolling; and continuous annealing, specifically, heating a cold-rolled plate to 830-860 DEG C during continuous annealing, then slowly cooling to 700-730 DEG C, finally, rapid cooling cold-rolled plate to 350-400 DEG C at 40-60 DEG C per second cooling rate to carry out overaging distribution treatment. The Q&P steel plate has advantages that the mechanical property is excellent, the yield strength is larger than or equal to 480 MPa, the tensile strength is larger than or equal to 800 MPa, the elongation percentage is greater than or equal to 25%, the n isgreater than or equal to 0.20, the yield ratio is less than or equal to 0.75, and the cold forming property is good. The Q&P steel plate and the preparation method have low requirements on process equipment, and are suitable for production of an existing continuous annealing production line.

Description

[0001] Technical field:

[0002] The invention belongs to the technical field of cold-rolled automobile steel production, and in particular relates to a high-strength plasticity cold-rolled Q&P steel plate with a tensile strength of 800 MPa and a preparation method thereof.

[0003] Background technique:

[0004] In recent years, with the rapid development of my country's automobile industry and the increasingly acute energy and environmental issues, in order to improve automobile fuel economy and reduce CO 2 To deal with global climate change, my country's "Passenger Car Fuel Consumption Limits" stipulates that by 2020, the average fuel consumption of passenger cars produced in my country should be reduced to 5 liters per 100 kilometers. The increasingly stringent emission standards put forward higher requirements for automobile manufacturers, and also provide development opportunities for the lightweight of automobile materials. For every 100 kg weight loss of the car, the f...

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