700 MPa级热轧双相钢的组织和性能

 采用热模拟并借助光学显微镜、SEM技术研究了双相钢的相变规律及不同工艺参数下的组织演变规律。根据热模拟结果在实验室试制出700 MPa级热轧双相钢，优化了轧制和冷却工艺参数。实验结果表明：热轧双相钢组织为多边形铁素体+马氏体岛，抗拉强度730 MPa，屈强比062，伸长率236%，达到了DP700级双相钢的性能要求，并讨论了热轧卷取温度对双相钢最终力学性能的影响。

Microstructure and Property of 700 MPa Grade Hot Rolled Dual Phase Steel

The phase transformation rule of test steels and the microstructure evolution for different process parameters were investigated by using thermal simulation, scanning electron microscope (SEM). 700 MPa grade hot rolled dual phase steels were pilot produced based on the results of thermal simulation, and the hot rolling and cooling parameters were also optimized. The results of experiments indicate that the microstructure is comprised of ferrite and martensite; tensile strength is 730 MPa, yield ratio is 062, and elongation rate is 236%, ratio the tested steel reaches the desired properties of DP700 class of these steels. And the influence of coiling temperature on final mechanical property was discussed.