Thin-wall high-strength hot rolled strip steel for square rectangular tube and manufacturing method thereof

Abstract

The invention relates to thin-wall high-strength hot rolled strip steel for a square rectangular tube and a manufacturing method thereof. The manufacturing method comprise the following steps that molten iron smelting is carried out to obtain a continuous casting slab; heating and preserving heat are carried out on the continuous casting slab; rough rolling is carried out on the heated continuouscasting slab to obtain an intermediate slab; finish rolling is carried out on the intermediate slab to obtain strip steel; the temperature of the strip steel subjected obtained after finish rolling is800-950 DEG C; laminar cooling is carried out on the strip steel; the strip steel is subjected to slow cooling in a temperature range of 650-800 DEG C before laminar cooling, and the slow cooling time is 3 10 seconds; coiling is carried out on the strip steel obtained after laminar cooling to obtain a hot rolled steel coil, the coiling temperature is 580-660 DEG C; and the hot rolled steel coil is slowly cooled to the room temperature, and the finished steel coil of the thin-wall high-strength hot rolled strip steel for the square rectangular tube is obtained. The hot rolled strip steel for the square rectangular tube prepared by the manufacturing method has excellent cold formability and weldability so as to adapt to roller press forming for production of structural members such as a rectangular tube and reprocessing requirement of the finished product tube, and the use requirements of a passenger car body framework are met.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting and rolling, in particular to a hot-rolled steel strip for thin-walled high-strength square rectangular pipes and a manufacturing method thereof. Background technique [0002] Energy conservation, emission reduction and green environmental protection have become important orientations for the sustainable development of the world economy today. The automobile industry, as a major player in energy consumption and emissions, must reduce fuel consumption and pollution emissions in order to achieve sustainable development. Lightweight vehicles are the key measures to achieve this goal. According to statistics, for every 10% reduction of a car, not only the power performance is obviously improved, but also the fuel is saved by 6-8%, and the emission is reduced by 4%. my country has become the world's largest automobile producer and consumer, so it is necessary to thoroughly lightweight ...

AI Technical Summary

Problems solved by technology

[0005] The invention provides a hot-rolled strip steel for thin-walled high-strength square rectangular pipe and its manufacturing method, which solves or partially solves the technical problem that the square rectangular pipe in the prior art cannot meet the requirements for the use of the bus body frame, and realizes the yield of the steel plate The strength can reach more than 800MPa, the tensile strength can reach more than 850MPa, the fluctuation of tensile strength is within 60MPa, the elongation rate can reach more than 24%, the plate shape and surface quality are excellent, and it has excellent cold formability and weldability, so as to adapt to roll forming The production of structural parts such as square and rectangular tubes and the reprocessing requirements of finished tubes meet the technical effect of the requirements for the use of bus body frames

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