Cold milling two-phase steel and preparation method thereof

Abstract

The invention provides cold milling two-phase steel and a preparation method thereof. The steel is prepared from the following ingredients in percentage by weight: 0.06 to 0.10 percent of C, 0.3 to 0.6 percent of Si, 2.2 to 2.6 percent of Mn, at most 0.02 percent of P, at most 0.02 percent of S, 0.03 to 0.08 percent of Alt, 0.8 to 1.1 percent of Cr, 0.03 to 0.06 percent of Nb, 0.01 to 0.03 percentof Ti, at most 0.005 percent of N and the balance of Fe and impurity elements. The tensile strength of the double-phase steel reaches 1000 MPa stage; Cr is used for replacing Mo on ingredient design;trace Nb element is added; the alloy cost is basically not increased; through the C content reduction and the low-temperature tempering treatment in the tempering stage, the martensite hardness is reduced; the hardness difference of the soft phase and the hard phase is reduced; the reaming performance of the material is further improved. In addition, the yield stress of the material is improved.

Description

Technical field [0001] The invention belongs to the technical field of steel materials, and particularly relates to a cold-rolled dual-phase steel and a preparation method thereof. Background technique [0002] With the increasingly stringent automotive fuel standards and the gradual advancement of lightweight body design, new automotive models have begun to use a higher proportion of advanced high-strength steels, especially high-strength steels with tensile strengths of over 1000MPa and above are increasingly being used. In the past few years, the amount of advanced high-strength steel used in each vehicle has increased more than expected. Although there have been alternative automotive materials such as aluminum, magnesium, and carbon fiber, from the perspective of the entire life cycle of production, use, and scrap recycling, the It has the lowest carbon dioxide emissions and has an incomparable competitive advantage with other materials. It will still be the leading material...

AI Technical Summary

Problems solved by technology

However, the hole expansion performance of existing high-strength steels is not ideal.

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