Ultralow carbon copper-containing automobile high-strength cold-rolled steel plate and manufacturing method thereof

Abstract

The invention discloses an ultralow carbon copper-containing automobile high-strength cold-rolled steel plate and a manufacturing method thereof. The chemical component in steel comprises, by weight, 0.004%-0.006% of C, 0.001%-0.003% of N, 0.2%-1.0% of Si, 0.2%-1.0% of Mn, 0-0.015% of P, 0-0.015% of S, 0.02%-0.04% of Als, 1.2%-2.4% of Cu and the balance Fe and inevitable impurities. The manufacturing method comprises the steps that the thickness of a continuous casting blank is controlled to be 350 mm or below; the hot rolling heating temperature is 980 DEG C-1050 DEG C, heat preservation is conducted for 30-60 min, the initial rolling temperature is 950 DEG C-1000 DEG C, the finish rolling temperature is 820 DEG C-880 DEG C, and the coiling temperature is 500 DEG C-550 DEG C; and the cold rolling reduction rate is not lower than 65%, the annealing heating temperature is 890 DEG C-920 DEG C, heat preservation is conducted for 20-40 min, the continuous casting blank is cooled to the room temperature at the speed of being not lower than 20 DEG C / s, and then aging is conducted for 30-60 min at the temperature of 550 DEG C-680 DEG C. The cold-rolled steel plate is low in production cost and excellent in corrosion resistance.

Description

technical field [0001] The invention relates to a high-strength cold-rolled steel sheet for automobiles and a manufacturing method thereof, in particular to an ultra-low-carbon high-strength cold-rolled steel sheet for automobiles containing copper and a heat treatment method thereof. Background technique [0002] With the increasing emphasis on environmental protection, the automotive industry is facing increasingly severe competition in technology and cost. Steel manufacturers, which are major material suppliers to the automotive industry, are also facing the same problem. It is the common pursuit of all iron and steel enterprises to provide steel products that are environmentally friendly, excellent in performance and low in cost. In order to ensure a certain corrosion resistance, hot-dip galvanizing of cold-rolled sheets is currently a widely used method. However, hot-dip galvanizing has adverse effects on the environment, and it is restricted in developed countries an...

AI Technical Summary

Problems solved by technology

[0004] The copper-containing steels in the above documents are all without exception added expensive nickel, niobium, molybdenum or one of them, which increases the cost of the steel and is fundamentally different from the composition design of this patent

Images