通过热模拟机研究了终轧温度对直接淬火和分区(DQ&P)钢的显微组织和力学性能的影响,场发射扫描电子显微镜(FE-SEM),电子背散射衍射(EBSD),和透射电子显微镜(TEM)。结果表明,随着精轧温度从920°C降低到840°C,原始奥氏体晶粒尺寸细化了31%,导致在840°C时形成最精细的马氏体板条。同时,较低的精轧温度导致较高的位错密度,从而提高了残余奥氏体的稳定性。此外,与传统的Q&P流程相比,具有相似化学成分的钢的综合力学性能可以通过DQ&P处理来提高。随着精轧温度从920℃降低到840℃,强度和总伸长率增加。屈服强度,抗拉强度,总伸长率达到最大值1121MPa,1134MPa,和11.7%,分别,在840°C
The effects of finishing rolling temperature on the microstructure and mechanical properties of a direct quenched and partitioned (DQ&P) steel were investigated by a thermal simulation machine, a field emission scanning electron microscope (FE-SEM), electron backscattering diffraction (EBSD), and a transmission electron microscope (TEM). The results show that the original austenite grain size was refined by 31% as the finishing rolling temperature decreased from 920 °C to 840 °C, leading to the formation of the finest martensite lath at 840 °C. At the same time, the lower finishing rolling temperature resulted in a higher dislocation density, and consequently improved the stability of the retained austenite. Moreover, compared to the conventional Q&P process, the comprehensive mechanical properties of a steel with similar chemical composition can be enhanced by DQ&P processing. With the decrease of finishing rolling temperature from 920 °C to 840 °C, the strength and total elongation increases. The yield strength, tensile strength, and total elongation reach the maximum values of 1121 MPa, 1134 MPa, and 11.7%, respectively, at 840 °C.