400MPa超细晶粒钢直流电阻闪光对焊接头组织的数值模拟

NUMERICAL SIMULATION ONMICROSTRUCTURE OF DC FLASHBUTT WELDING FOR AN 400 MPaULTRA-FINE GRAIN STEEL

对超细晶粒钢直流闪光对焊过程进行了有限元分析。根据计算的焊接温度场和基于EDB模型的Monte Carlo(MC)模拟时间与实际焊接时间的关系,建立了直流闪光对焊过程显微组织的演化模型,对超细晶粒钢筋焊接接头的奥氏体晶粒长大进行了模拟研究,同时考虑了温度梯度对热影响区晶粒长大的热钉轧作用。结果表明,MC模拟技术能预测闪光对焊接头的晶粒大小、尺寸分布,为合理地制定焊接规范、提高接头质量提供有效的分析手段。

A direct current flash butt welding (DC FBW) process is analyzed for an ultra fine grain steel using finite element method. According to the computed temperature field and the relation between real welding time and Monte Carlo (MC) simulation time established from the experimental data based (EBD) model, microstructure evolution model is built up for the DC FBW. Then, the Austenite grain growth of the welded joints for the ultra fine grain reinforcement steel bar is simulated. At the same time the heat pinning effect of temperature gradient on the grain growth in the heat affected zone is considered. The results indicate that the grain size and distribution can be predicted using the Monte Carlo simulation technology for the DC FBW process. Also, the technology is a powerful tool for determining welding parameters and improving welds quality.