含铌冷轧DP780钢的连退工艺对组织及性能的影响

 通过成分工艺优化，在传统冷轧铁素体和马氏体双相钢DP780的显微组织上引入了一定体积分数的残余奥氏体，研究了冷轧退火工艺参数对双相钢DP780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-力学性能的本质关系。结果表明，通过在传统冷轧铁素体和马氏体双相钢的组织上引入了体积分数为5%～7%的残余奥氏体，不仅可以获得ReL/Rm≤0.5]的超低屈强比型冷轧DP780，也改善了成型性能。

Effect of continuous annealing process on microstructure and properties of DP780 containing niobium

By means of the optimization of the composition and the process parameters,the influence of cold rolling process parameters on the microstructure and mechanical properties of dual phase steel DP780 were investigated and a certain amount of retained austenite was added in the microstructure of the conventional cold rolled ferrite and martens-ite dual phase steel DP780. In order to control the proportion,size,morphology and distribution of first ferrite,second ferrite,martensite,retained austenite in the microstructure,the essential relationship of the process parameters,micro-structure and mechanical properties was obtained by adjusting the continuous annealing process. The results show that the microstructure with 5%-7%of residual austenite in traditional cold-rolled ferrite and martensite dual phase steel not only can be obtained ultra-low yield ratio with Rp0.2/Rm less than or equal to 0.5,but also improve the formability of cold-rolled DP780.