1000 MPa-grade good-cold-machining-property low-cost cold-rolling dual-phase steel and manufacturing method thereof

Abstract

The invention discloses 1000 MPa-grade good-cold-machining-property low-cost cold-rolling dual-phase steel and a manufacturing method thereof, and belongs to the technical field of iron and steel smelting. The 1000 MPa-grade good-cold-machining-property low-cost cold-rolling dual-phase steel comprises the following chemical components of, according to the mass percentage, 0.13-0.22% of C, 1.20-1.70% of Mn, 0.20-0.50% of Si, 0.30-0.80% of Als, less than or equal to 0.015% of P, less than or equal to 0.0010% of S, less than or equal to 0.004% of N, 0.20-0.50% of Cr, 0.010-0.05% of Nb, 0.0005-0.0025% of Ca, less than or equal to 0.002% of T[O], and the balance Fe and unavoidable impurities; and the sum of the mass percentage of Si and Als is greater than or equal to 0.50% and is less than orequal to 1.00%. The manufacturing method comprises the steps of a steel making technology, an LF refining technology, a RH refining technology, a continuous casting technology, a hot rolling technology, a cooling technology, a winding technology, an acid pickling technology, a cold rolling technology, an annealing technology and a leveling technology. On the basis that the design of the relativelylow content of alloy elements is selected, the rolling technologies and the cooling technology are combined, so that the requirement of a prepared product on a production technology production line is not high on the basis that the prepared product has the relatively high intensity and cold bending property.

Description

technical field [0001] The invention relates to a cold-rolled dual-phase steel, which belongs to the technical field of iron and steel smelting, in particular to a low-cost cold-rolled dual-phase steel with good 1000MPa-level cold working performance and a manufacturing method thereof. Background technique [0002] In recent years, in order to reduce energy consumption during the use of automobiles and reduce CO 2 Emissions, automotive steel is developing in the direction of high strength and high toughness, ultra-high-strength steel of 1000MPa level and above is one of its main development directions, and dual-phase steel has high work hardening rate and formability, so the level of 1000MPa and above Ultra-high-strength dual-phase steels are widely used. [0003] For example, the Chinese invention patent application (application publication number: CN105803321A, application publication date: 2016-07-27) discloses a 980MPa vanadium-containing ultra-fine grain cold-rolled du...

AI Technical Summary

Problems solved by technology

Although the performance index of the application includes indicators such as cold bending and hole expansion rate, for some parts with high drawing and bending performance, the plasticity and cold bending performance still cannot meet the requirements, and the composition design has added High alloying elements such as Si, Mn, Nb, Ti, etc., on the one hand lead to higher alloy costs, on the other hand, in the production process, continuous casting and rolling are difficult, and production needs to be carried out in special high-strength steel production lines

[0006] In short, when the current technology adopts higher carbon content to produce 1000MPa grade dual-phase steel, when using higher carbon content, the addition of alloying elements is relatively small, and the tensile strength can reach more than 1000MPa, but it cannot obtain better cold bending and Hole expansion rate and other properties, these products cannot meet the demand for parts with high formability requirements, and when using lower carbon content to produce 1000MPa grade steel, in order to obtain better strength / elongation and cold bending and hole expansion of the product Higher alloying elements need to be added to the steel, but on the one hand, the addition of alloying elements increases the cost of the alloy, resulting in higher alloy costs; on the other hand, it increases the difficulty of the production process, making it difficult to produce in general production lines

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