Production method of 260-330MPa low-alloy high-strength steel

Abstract

The invention discloses a production method of 260-330MPa low-alloy high-strength steel. The low-alloy high-strength steel comprises the following chemical components by mass percentage: 0.05-0.09% of C, 0.15-0.60% of Mn, less than or equal to 0.015% of S, less than or equal to 0.020% of P, less than or equal to 0.50% of Si, less than or equal to 0.020% of Nb, less than or equal to 0.020% of Ti, 0.020-0.060% of Als, less than or equal to 30ppm of N, and the balance of Fe and unavoidable impurities. The method comprises the procedures of hot rolling, pickling, cold rolling, box annealing, leveling and rewinding. The low-alloy high-strength steel obtained by the method has yield strength of 260-330MPa, tensile strength of 350-430MPa, percentage elongation after fracture of greater than or equal to 26.0%, and good combination of strength and plasticity. The method achieves stable production of the product via optimal design of components, and can obtain the cold rolling low-alloy high-strength steel with stable mechanical properties and good cold forming performance.

Description

technical field [0001] The invention relates to a production method of high-strength steel, in particular to a production method of 260-330MPa grade low-alloy high-strength steel. Background technique [0002] Cold-rolled annealed low-alloy high-strength steel has high strength, but also good plasticity, low temperature toughness and weldability. Therefore, it is widely used in automobile structural parts and building structural parts. At present, cold-rolled annealed low-alloy high-strength steel can be produced by bell annealing or continuous annealing, but these two annealing methods have different heat treatment characteristics, such as bell annealing with slow heating and cooling rates and long heating times, while continuous annealing heating and cooling rates Fast, short heating time, this process feature determines that under the same composition, the grain size of the finished product after annealing in the two methods is very different, and the yield ratio is very ...

AI Technical Summary

Problems solved by technology

At present, cold-rolled annealed low-alloy high-strength steel can be produced by bell annealing or continuous annealing, but these two annealing methods have different heat treatment characteristics. Fast, short heating time. This process characteristic determines that under the same composition, the grain size and yield ratio of the finished product after the two annealing methods are greatly different. Therefore, in product design, in order to obtain the standard mechanical properties, different compositional design concepts must be adopted

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