Method for preparing high-strength steel plate with thickness of 20 mm

Abstract

The invention discloses a method for preparing a high-strength steel plate with the thickness of 20 mm. According to the method, a controlled rolling and controlled cooling process is adopted; the continuous casting thickness before rolling is 150-200 mm; the heating temperature is 1,180-1,200 DEG C; an austenite recrystalline region and an austenite non-recrystalline region are adopted for controlling rolling in a two-stage manner; the reduction rate of each gate in rough rolling is 10-15%; the final rolling temperature in rough rolling is 1,000-1,050 DEG C; a middle blank with the 1.6-2.0 times of the thickness of a finished product is roughly rolled; the initial rolling temperature in finish rolling is 850-870 DEG C; the reduction rate of each gate is 10-15%; the final rolling temperature in finish rolling is 800-830 DEG C; laminar cooling is adopted after rolling; the final cooling temperature is 550-630 DEG C; the cooling velocity is 7-10 DEG C / s; subsequently air cooling is performed; TMCP (Thermal Mechanical Control Processing) rolling is performed in a hot rolling workshop so as to obtain the high-strength steel plate which is 20 mm thick and comprises a bainite structure. Due to adoption of a thermal treatment process, a superfine crystal structure is obtained, and a material has the characteristics of low yield ratio, superplasticity, high strength and the like.

Description

technical field [0001] The invention relates to a high-strength steel, in particular to a preparation method of a 20mm thick high-plastic high-strength steel plate. Background technique [0002] With the development of society and economy, the iron and steel industry is facing three major pressures: saving resources, saving energy, and protecting the environment. Therefore, improving steel quality, reducing cost, and greatly improving its comprehensive mechanical properties have become the main direction of steel material research. [0003] Generally, the yield strength and tensile strength of steel are proportional to the -1 / 2 power of the grain diameter d, and grain refinement will significantly increase the yield strength and tensile strength of steel. The increase of the yield ratio will lead to a significant decrease in the cold formability of the steel. Therefore, high yield ratio and low plasticity are still difficult problems to be solved in the existing ultra-fine...

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Problems solved by technology

The increase of the yield ratio will lead to a significant decrease in the cold formability of the steel

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