980MPa grade cold-rolled dual-phase steel with low requirements for cooling capacity of production line and manufacturing method thereof

Abstract

The invention discloses 980MPa grade cold-rolled dual-phase steel with low requirements for cooling capacity of a production line and a manufacturing method thereof, and belongs to the technical fieldof steelmaking. The 980MPa grade cold-rolled dual-phase steel consists of the following chemical composition of, by mass, 0.14-0.17% of C, 0.10-0.30% of Si, 1.8-2.2% of Mn, less than or equal to 0.012% of P, 0.4-0.6% of Cr, 0.02-0.07% of Alt, 0.01-0.02% of Nb, 0.0005-0.002% of B, less than or equal to 0.005% of S, less than or equal to 0.005% of N, and the balance Fe and unavoidable impurities. According to the chemical composition, the 980MPa grade cold-rolled dual-phase steel is manufactured through smelting and slab casting process, and slab heating, hot rolling, coiling, pickling, cold rolling and continuous annealing process. In the continuous annealing process, the annealing temperature is controlled to be 800-820 DEG C, the cooling rate of a slow cooling section is less than 8 DEGC / s, the finish temperature of the slow cooling section is 620-640 DEG C, the finish temperature of a rapid cooling section is 300-320 DEG C, the cooling rate of the rapid cooling section is less than30 DEG C / s, and the over aging temperature is 270-310 DEG C. The dual-phase steel is prepared according to the chemical composition and the process of the 980MPa grade cold-rolled dual-phase steel with the low requirements for the cooling capacity of the production line and the manufacturing method thereof, the requirements for the rapid cooling rate in the production line are low, and the 980MPagrade cold-rolled dual-phase steel with the low requirements for the cooling capacity of the production line and the manufacturing method thereof can be used in a conventional common production line.

Description

technical field [0001] The invention relates to a method for manufacturing high-strength cold-rolled dual-phase steel, belonging to the technical field of steelmaking, and in particular to a 980MPa grade cold-rolled dual-phase steel with low requirements on the cooling capacity of a production line and a manufacturing method thereof. Background technique [0002] With the development of the automobile industry, the market demand for vehicles with small displacement and low energy consumption is increasing day by day. According to statistics, for every 10% reduction in vehicle quality, fuel consumption can be reduced by 3-7%. Due to considerations of cost, energy, safety, and the environment, automobile lightweight is the development direction of the modern automobile industry. Optimizing and upgrading the performance of steel materials, which account for 55-70% of the total weight of the vehicle, plays an important role in the process of vehicle lightweighting. In order to...

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Problems solved by technology

With the continuous upgrading of lightweight, 980MPa grade cold-rolled dual-phase steel will gradually be applied in large quantities in future automotive materials. The principle is that it has high requirements on the cooling capacity of the production line, and generally needs to be produced on a special line for ultra-high-strength steel. Only a few domestic steel mills have mass production capacity

[0004] At present, Wuhan Iron and Steel Co., Ltd. only has an ordinary automobile sheet production line, and has not built a dedicated ultra-high-strength production line. The existing continuous annealing production line generally has a cooling rate of less than 30°C / s. With the continuous increase in market demand for 980MPa grade cold-rolled dual-phase steel, how to The problem of producing high-quality ultra-high-strength steel products on the current production line needs to be solved urgently

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