High-plasticity dual-phase steel and production method thereof

Abstract

The invention discloses high-plasticity dual-phase steel and a production method thereof. The high-plasticity dual-phase steel comprises the following chemical components in percentage by mass: 0.17 to 0.23 percent of C, 0.17 to 0.37 percent of Si, 0.50 to 0.80 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.005 percent of S, 0.70 to 0.95 percent of Cr, 0.015 to 0.025 percent of Al, 0.010 to 0.020 percent of Ti, less than or equal to 0.02 percent of Ni, less than or equal to 0.05 percent of Cu, less than or equal to 0.005 percent of Mo, 0.0015 to 0.0018 percent of O and the balance Fe and inevitable impurities. The production method of the high-plasticity dual-phase steel comprises the following steps of converter smelting, argon station treatment, LF refining, continuous casting, rolling and cooling. According to the steel, a proper amount of Ti and Al alloy is added to conduct microalloying on the steel, the quality of molten steel is further purified, and by means of the characteristics of the Ti alloy and the characteristic that a separated Ti-containing compound can effectively hinder grain coarsening, the prepared steel has the diameter phi of 24-100 mm, the yield strength of 850-1000 MPa, the tensile strength of 1000-1150 MPa, the ductility of 14-17.5%, the percentage reduction of area of 44.5-48% and the impact energy of 60-75 J; and the hardenability and plasticity index of the steel are greatly improved.

Description

technical field [0001] The invention relates to the technical field of iron and steel materials, in particular to a high-plastic dual-phase steel and a production method thereof. Background technique [0002] The traditional martensite (bainite) plus ferrite matrix dual-phase steel contains the following chemical components in mass fractions: C: 0.17-0.23%, Si: 0.17-0.37%, Mn: 0.50-0.80%, P≤0.030%, S≤0.020%, Cr: 0.70~0.95%, Ni≤0.30%, Cu≤0.20%, Mo≤0.10%, the balance is Fe and unavoidable impurities; the structure obtained after quenching is martensite+ Ferrite, in which martensite is distributed in the form of islands between ferrite grains, that is: 10% to 20% martensite plus 80% to 90% ferrite structure, this structure is made of low carbon steel Or low-carbon alloy steel obtained through critical zone treatment or control; the mechanical properties required by traditional dual-phase steel are low yield strength (540-750MPa, with continuous yield behavior), high tensile st...

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Problems solved by technology

[0008] The purpose of the present invention is to solve the problems of high equipment cost, high technical difficulty and difficult operation in the methods for improving the hardenability and plasticity index of dual-phase steel in the existing methods, and it is difficult to realize low-cost, high-efficiency green production. problem, and provide a kind of high plasticity dual-phase steel and its production method

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