Thin-gauge and high-strength hot-rolled steel strip for cold forming and production method of thin-gauge and high-strength hot-rolled steel strip

Abstract

The invention discloses a thin-gauge and high-strength hot-rolled steel strip for cold forming and a production method of the thin-gauge and high-strength hot-rolled steel strip. The steel strip comprises the chemical components in percentage by weight: 0.04-0.10% of C, 0.05-0.25% of Si, 1.0-1.5% of Mn, less than or equal to 0.010% of P, less than or equal to 0.008% of S, 0.03-0.07% of Nb, 0.08-0.20% of V, 0.10-0.20% of Ti, 0.05-0.20% of Mo, less than or equal to 40ppm of N, less than or equal to 50ppm of O and the balance of Fe and unavoidable impurities. The production method of the steel strip comprises the following steps: 1) element smelting; 2) continuous casting; 3) rolling; and 4) natural cooling of a hot-rolled steel coil after rolling. By using the thin-gauge and high-strength hot-rolled steel strip, the thin-gauge and high-strength hot-rolled steel strip for cold forming is stably produced in batches on the traditional hot rolling production line, and the comprehensive performances of steel are improved.

Description

technical field [0001] The invention relates to a hot-rolled steel strip, in particular to a thin-gauge, high-strength hot-rolled steel strip for cold forming and a production method thereof. Background technique [0002] At present, with the continuous improvement of energy saving, environmental protection and low-cost manufacturing requirements, the automobile and bus industry is gradually developing towards high strength, thinner and lighter weight. Traditional thick-gauge low-strength grade steel can no longer meet the structural design and manufacturing needs of new models. It is urgent to develop thin-gauge high-strength steel, which can reduce the weight of the body through strengthening thinning and structural optimization, shorten the vehicle manufacturing cycle and improve vehicle safety. [0003] In the past, in order to meet the demand of thin gauge and high strength, cold-rolled strip steel was often used to produce cold-formed steel. Although the strength and t...

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Problems solved by technology

[0005] Based on the traditional hot rolling production line, the production of thin-gauge high-strength cold-forming hot-rolled steel strips with a thickness of less than 3 mm faces many technical difficulties: 1) The contents of P, S, O, and N in molten steel must be controlled at a relatively low level. Low level, and to ensure the yield of titanium, very strict requirements on the smelting process; 2) to obtain the ideal ferrite and bainite structure, while controlling the morphology, size and quantity of Ti precipitates to ensure its High strength, high toughness and performance uniformity are difficult to achieve by conventional rolling processes; 3) For this kind of steel strip with high strength and thin wall thickness, it is required that the double-sided roughness should be controlled within three thousandths, and the plate shape and coil shape very difficult to control

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