Q460D钢马氏体相变塑性的实验研究

Experimental research of transformation plasticity for Q460D steel

为建立准确的低碳马氏体钢淬火过程数值计算模型,采用Gleeble3500热模拟实验机对单轴应力作用下Q460D钢马氏体相变的相变塑性进行了研究.通过分析无应力循环和外加应力的实验过程,在试样径向膨胀曲线中分离出了相变塑性应变.实验结果表明,相变塑性应变随外加应力的增加而增大,相变塑性应变与施加应力大致呈线性关系.采用Greenwood-Johnson模型得到了Q460D钢的相变塑性系数.利用所得相变塑性系数计算出膨胀曲线,并与实测膨胀曲线进行比较,计算值与实验值吻合较好,文章结果可用于Q460D钢淬火过程的数值模拟.

To build accurate numerical model of quenching process of low-carbon martensitic steel, the martensitic phase transformation plasticity of Q460D steel under uniaxial stress was studied on Gleeble 3500 thermal simulation machine. Based on the analysis of free expansion and applied stress, the transformation plasticity strains were separated from radial expansion curves. The experimental results show that the phase transformation plasticity increases with the enhancement of applied stress, the relationship between phase transformation plasticity and applied stress is roughly linear. By Greenwood-Johnson model, the transformation plasticity parameter of Q460D steel was obtained. Using the acquired parameter, expansion curves were calculated and compared with the measured curves, and they were in good agreement.