超低屈强比冷轧DP780钢的组织及性能研究

Study on Microstructure and Mechanical Properties of Cold Rolled DP780 Steel with Ultra Low Yield Ratio

研究了冷轧退火工艺参数对DP780双相钢的显微组织和力学性能的影响。通过调整连续退火工艺来控制显微组织中一次铁素体、二次铁素体、马氏体、残余奥氏体的比例、尺寸、形貌、分布,同时获得了连退工艺参数、显微组织、力学性能的关系。结果表明,在传统冷轧铁素体和马氏体双相钢的组织中有5%~7%的残余奥氏体,不仅可以获得屈强比≤0.5的超低屈强比冷轧DP780型钢,也改善了成形性能。

The influences of annealing process parameters after cold rolling on microstructure and mechanical properties of DP780 dual phase steel were investigated. The proportion, size, morphology and distribution of first ferrite, second ferrite,martensite and retained austenite in the microstructure were controlled, and the relationship among the process parameters,microstructure and mechanical properties was obtained by adjusting the continuous annealing process. The results show that 5%-7% residual austenite in traditional cold-rolled ferrite and martensite dual phase steel microstructure, not only can obtain cold rolled DP780 steel with the ultra low yield ratio, which is less than or equal to 0.5, but also improve the formability.