Method for improving low-temperature impact toughness of high-strength steel hot rolled plate coil for engineering machines

Abstract

The invention provides a method for improving the low-temperature impact toughness of a high-strength steel hot rolled plate coil for engineering machines, which belongs to the technical field of steel for engineering machines. The method adopts a hot feeding and hot loading process, and the control technical parameters in the process include a hot loading temperature, a pouring superheat degree and a drawing speed, wherein the hot loading temperature is 500 to 600 DEG C, the pouring superheat degree is 18 to 20 DEG C, and the drawing speed is controlled to be 1.2 to 1.4m / min. Production is carried out in a mode of coarsely rolling by two machine frames and finely rolling by six machine frames, six-pass rolling is adopted in a coarse rolling phase, six-pass fine rolling is adopted in a fine rolling phase, and the rolling reduction in a non-recrystallized areas of austenite is 65 to 70 percent. A front-end laminar flow cooling mode is adopted for quickly cooling to a target temperature after fine rolling, and the cooling speed is improved to 10 to 15DEG C / s. After being removed from the production line, the plate coil is cooled by wind to 100 DEG C and then by air to room temperature. The method has the advantages of ensuring high strength and high toughness at the same time, saving consumption and improving production efficiency.

Description

technical field [0001] The invention belongs to the technical field of steel for engineering machinery, and in particular relates to a method for improving the low-temperature impact toughness of hot-rolled coils of high-strength engineering machinery steel, which is applied to the improvement of low-temperature toughness of low-alloy high-strength engineering machinery steel. Background technique [0002] High-strength engineering machinery steel is a low-alloy high-strength steel based on C-Mn steel and added with microalloying elements such as Mo, Nb, V, and Ti. At present, high-strength steel plates are widely used in the construction machinery industry and coal mining machinery industry, and the required thickness is mainly 4-80mm. Among them, steel plates with a thickness below 20mm are mainly coiled flat products, and most of them are used in the construction machinery industry. It is used to manufacture crane arms, frames, etc.; steel plates with a thickness of more ...

AI Technical Summary

Problems solved by technology

Since hot-rolled coils do not have the same strong control and cooling means as medium and thick plates, it is often necessary to add more alloying elements. For example, the addition of Ti can reach more than 0.1%. In addition to fine-grain strengthening, certain precipitation strengthening is also required as a supplement. , which often results in a decrease in its low-temperature impact toughness

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