1180MPa-grade high-plasticity bainite complex phase steel plate for automobile and preparation method for 1180MPa-grade high-plasticity bainite complex phase steel plate

Abstract

The invention belongs to the field of manufacturing of steel for automobiles and particularly relates to a 1180MPa-grade high-plasticity bainite complex phase steel plate for an automobile and a preparation method for the 1180MPa-grade high-plasticity bainite complex phase steel plate. The 1180MPa-grade high-plasticity bainite complex phase steel plate is prepared from the following components inpercentage by weight: 0.03-0.20 percent of C, 0.05-1.50 percent of Si, 0.5-2.5 percent of Mn, smaller than or equal to 0.05 percent of P, smaller than or equal to 0.05 percent of S, 0.01-0.04 percentof Nb, 0.01-0.04 percent of Ti, 0.01-0.15 percent of V, 0. 015-1.50 percent of Al, substitutable components, including 0-2.0 percent of Cr, 0-0.5 percent of Mo and 0.05-0.50 percent of Cu, and the balance of Fe and inevitable impurities. The preparation method comprises the following steps of converter smelting, continuous casting of a medium-thin slab, hot continuous rolling, acid pickling cold rolling and continuous annealing. For the 1180MPa-grade high-plasticity bainite complex phase steel plate for the automobile and the preparation method disclosed by the invention, the chemical components of the steel take the C, the Si and the Mn as main elements, the content of the C is smaller than 0.25, and the alloy cost is lowered; by adopting the production process of converter smelting, continuous casting and continuous rolling of the medium-thin slab, acid pickling cold rolling and continuous annealing, the production process is simplified, the cost is low, new production equipment doesnot need to be added, and the production process is stable; and the obtained material has the force and energy characteristics of high yield, high tensile strength and high extension.

Description

technical field [0001] The invention belongs to the field of steel manufacturing for automobiles, and in particular relates to a 1180MPa high-plasticity bainite composite steel plate for automobiles and a preparation method thereof. Background technique [0002] At this stage, advanced high-strength steels for automobiles are widely used in car bodies, such as Q&P980 / 1180, TRIP980 / 1180, DP980 / 1180, TBF / CFB, and TWIP980 / 1180, etc., and are widely used in anti-collision beams, door sills, and B-pillar reinforcements Other reinforcements and more complex body structural parts such as front longitudinal beams, rear longitudinal beams, and lower ends of A-pillars. However, as the strength of high-strength steel increases, the cost of the alloy increases and the production process becomes more and more complicated. For example, the ratio of C and Mn alloys in TWIP series steels has been doubled, which has greatly increased the cost of materials; for Q&P series steels, technical m...

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Problems solved by technology

The production process of cold rolling-continuous annealing is used to produce high-strength steel with a strength level of 1200MPa, but the cost of the alloy in this invention is too high, especially the high content of C and Mn will lead to the decline of subsequent resistance spot welding performance

In addition, the production technology adopts the over-aging treatment of quenching and body temperature, which increases the difficulty of production and reduces the stability of production

[0004] CN102181788A discloses "a 1100-1200MPa grade ultra-high-strength steel and its production method", its main chemical components are: C: 0.15%-0.18%, Si: 0.2%-0.25%, Mn: 0.85%-1.25%, Cr : 0.20~0.60%, Mo: 0.45~0.65%, V: 0.035~0.060, Nb: 0.015%~0.020%, Ni: 0~0.55%, Cu: 0~0.35%, P≤0.015%, S≤0.01% , V ≤ 0.02%, Ti: 0.08% ~ 0.015%, Al: 0.01% ~ 0.06%, the product is cold rolled annealed steel plate, but the elongation of the 1200MPa grade steel is 11% ~ 13%, it is difficult to meet the high turnover Body Structural Parts Requirements

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