Continuous annealing method of DC01 steel plate with low yield and high tensile strength for automobiles

Abstract

The invention relates to a continuous annealing method of DC01 steel plate with low yield and high tensile strength for automobiles, belonging to the field of metallic materials processing. The chemical composition of the steel plate is as follows by mass percentage: 0.02-0.04% of C, 0.2-0.35% of Mn, less than or equal to 0.03% of Si, less than or equal to 0.010% of P, less than or equal to 0.010% of S, 0.02-0.06% of Als, 0.0020-0.0050%of N, and the rest being Fe. The hot rolling parameter is as follows: heating temperature at 1250+/-30 DEG C; finishing temperature at 930+/-20 DEG C; coiling temperature at 730+/-20 DEG C; cold rolling reduction ratio being controlled at 75-85%; soaking time for 50-100s; annealing temperature at 780+/-20 DEG C; outlet temperature of the slow-cooling section at 675+/-20 DEG C; outlet temperature of the rapid-cooling section at 400+/-20 DEG C; overaging temperature at 350+/-20 DEG C; and level elongate ratio being 0.9+/-0.3%. The generated steel plate has the advantages of low yield strength, high tensile strength, fine formability, high product quality and considerable economic benefit.

Description

technical field [0001] The invention belongs to the field of metal material processing, in particular to a continuous annealing method for low-yield high-tensile strength DC01 steel plates for automobiles, which is suitable for low-carbon aluminum killed steel plates (DC01). Background technique [0002] Low-carbon aluminum killed steel plate (DC01) is commonly produced by bell annealing. With the update of production equipment, it is now produced by continuous annealing process in large quantities. It is mostly used in the automotive industry, home appliance industry and construction fields. According to the requirements of GB / T 5213-2001 for similar steel types, its composition is: C, ≤0.08%; Mn, ≤0.4%; Si, ≤0.03%; P, ≤0.020%; S, ≤0.025%; Als, 0.02-0.07%, the balance is Fe. The national standard requires its yield strength to be ≤240MPa, and its tensile strength to be 270-350MPa, n 90 ≥1.8, r 90 ≥1.6. In the European standard EN 10130-2006, its composition requirements...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a continuous annealing method for low-yield and high-tensile-strength DC01 steel plates for automobiles, which solves the problems of low-carbon aluminum-killed steel (DC01) with high yield strength, low tensile strength, poor formability and aging resistance. bad question

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