Production method for two-phase automobile steel plate with low yield-strength ratio and high strength

Abstract

The invention discloses a two-phase automobile steel plate with low yield-strength ratio and high strength and a production method of the two-phase automobile steel plate, belonging to the technical field of steel for automobiles. The two-phase automobile steel plate comprises the following chemical components: 0.1-0.40wt% of C, 3.0-8.0wt% of Mn, less than or equal to 0.020wt% of P and less than or equal to 0.02wt% of S; on the basis, the two-phase automobile steel plate can be additionally provided with one or more of the following elements: 0.1-3.0wt% of Ni, 0.2-3.0wt% of Cr, 0.1-0.8wt% of Mo, 0.3-2.3wt% of Si, 0.5-2.0wt% of Cu, 0.0005-0.005wt% of B, 0.02-0.10wt% of Nb, 0.002-0.25wt% of [N], 0.05-0.25wt% of Ti, 0.02-0.25wt% of V, 0.015-0.060wt% of Al, 0.002-0.005wt% of RE (Rare Earth) and 0.005-0.03wt% of Ca. The two-phase automobile steel plate has the advantages that the two-phase automobile steel plate with low yield strength, high tension strength and favorable elongation can be produced through annealing within short time; the performance indexes of the two-phase automobile steel plate are as follows: two-phase steel with the tension strength of 980MPa has the yield-strength ratio of not larger than 0.55 and the elongation of larger than 22%, and two-phase steel with the tension strength of 1180MPa has the yield-strength ratio of not larger than 0.55 and the elongation of larger than 17%.

Description

Technical field [0001] The invention belongs to the technical field of production of steel sheet coils for automobiles, and in particular provides a low-yield ratio, high-strength dual-phase steel sheet for automobiles and a production method, and a continuous annealing production line produces a high-strength automobile with excellent formability The dual-phase steel sheet coil with steel has a tensile strength above 1GP, but the ratio of yield strength to tensile strength is between 0.45-0.65, and at the same time, it has sufficient elongation to increase the strength of the automobile plate to achieve weight reduction. , It also ensures the easy formability of the steel plate when stamping. Background technique [0002] With the improvement of automobile lightweight and safety requirements, the strength of steel used in automobile structural parts is required to continue to increase, so as to achieve weight reduction with thinner steel plates while meeting the safety precondit...

AI Technical Summary

Problems solved by technology

However, with the substantial increase in the tensile strength of the steel plate, it is usually accompanied by an increase in yield strength and a decrease in elongation.

The increase in yield strength makes the material difficult to deform, so the power of the punching machine and the load on the die are greatly increased, and the life of the die is reduced; in addition, the increase in yield strength leads to an increase in the yield ratio, a decrease in the uniform elongation of the material, and a decrease in the elongation If the rate drops, the steel plate will crack during stamping and be scrapped

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