高应变率下Q345/304不锈钢焊接接头的动态力学性能及其显微组织分析

Dynamic mechanical property and microstructure analysis of Q345/304 stainless steel welded joint under high strain rate

利用分离式霍普金森压杆试验装置(SHPB)对碳钢焊接接头进行应变速率为1000~3500 s^(-1)范围内的动态力学试验,获得了不同应变速率下的应力-应变关系曲线,利用金相显微镜对压缩后的接头组织进行了分析,试验结果表明:碳钢焊接接头的应变速率强化效应不明显,但是表现出显著的应变强化,随着应变速率的升高,材料发生局部塑性变形更加剧烈,并采用修正的Johnson-Cook本构方程拟合了Q345/304不锈钢焊接接头在高应变速率条件下的本构关系,拟合曲线与试验数据吻合较好。

The dynamic mechanics behavior of the Q345 and 304 stainless steel welded joint was measured at strain rate ranging from 1000 to 3500 s^(-1) with the split hopkinson pressure bar(SHPB)apparatus,and the stress-strain relationship curve under different strain rates were obtained.The microstructure of the compressed joint was analyzed by metallographic microscope.The results showed that the Q345 and 304 stainless steel welded joint had no obvious strengthening effect on strain rate,but shows significant strain strengthening,with the increase of strain rate,with the increase of strain rate.The high strain rate constitutive equation of Q345 and 304 stainless steel welded joint was obtained based on modified Johnson-Cook constitutive model,the modified Johnson-Cook constitutive model was consistent with the experimental data.