Ultra-high-strength cold-rolled dual-phase steel with weather resistance and manufacturing method thereof

Abstract

The invention provides an ultrahigh-strength cold rolled dual-phase steel with weatherability and a manufacturing method of the ultra-high strength cold rolled dual-phase steel. The ultra-high strength cold rolled dual-phase steel is prepared from the following components in percentage by weigh (wt%): 0.10-0.16 percent of C, 0.10-0.50 percent of Si, 1.4-2.2 percent of Mn, 0.30-0.79 percent of Cr, 0.08-0.20 percent of Ni, 0.20-0.50 percent of Cu, 0.01-0.05 percent of Nb, 0.02-0.05 percent of Ti, 0.015-0.045 percent of Al, no larger than 0.020 percent of P, no larger than 0.007 percent of S, no larger than 0.008 percent of N and the balance of Fe and inevitable impurities. The manufacturing method comprises the following steps: according to the chemical components, smelting, and continuously casting to obtain a casting slab; reheating the casting slab until the temperature is above 1250 DEG C, and carrying out finish rolling, wherein the initial rolling temperature is 1040-1100 DEG C, the finishing temperature is 880-930 DEG C, the coiling temperature is 580-660 DEG C, and the cold rolling reduction is 60-70 percent; and carrying out continuous annealing with two stages of slow cooling and fast cooling. According to the manufacturing method, the ultra-high strength cold rolled dual-phase steel with the weatherability, the yield strength higher than 700 MPa, the tensile strength higher than 800 MPa and the elongation higher than 5 percent can be obtained.

Description

technical field [0001] The invention belongs to the technical field of high-strength cold-rolled dual-phase steel production, and in particular relates to a weather-resistant ultra-high-strength cold-rolled dual-phase steel used for containers, automobiles, etc. and a manufacturing method thereof. Background technique [0002] For container transportation, there is an urgent need for lightweight containers to increase the weight of goods that can be transported at a time, and the development trend is to increasingly use containers with a length of 45 to 53 feet. Therefore, the first thing to consider in the manufacture of lightweight containers is to reduce the thickness of the steel plate by manufacturing high-strength steel. Due to the limitation of the thickness of the hot rolling mill, the thickness of the weathering steel plate produced by hot rolling is generally thicker. In order to meet the needs of thinning steel plates, the development of ultra-high-strength cold-...

AI Technical Summary

Problems solved by technology

This technology is only suitable for small batch production, and it is difficult to meet the needs of mass production, and the uniformity of the entire coil is not easy to guarantee

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