船用钢板EH36焊接过程的温度场演变和分析

Evolution and Analysis of Temperature Field of Welding Process for Marine Steel Plate EH36

为探索船用钢板EH36焊接过程的温度演变机理,基于ABAQUS和二次开发技术,考虑材料热物理参数非线性变化以及焊件与周围环境的对流和辐射,对EH36焊接温度场进行模拟,并实验验证热循环曲线.结果表明,焊接2～3 s后,焊缝区达到准稳态温度场;第3层第1道焊存在未填充金属不易热传递,等温线偏移;热循环曲线经历4个峰值并逐渐减小,实验和模拟结果吻合较好.为预测焊接过程及焊件的组织、性能和残余应力提供了依据.

The aim of the article is to explore the temperature evolution mechanism of the welding process for marine steel plate EH36. Based on ABAQUS software,numerical model of EH36 was established using birth-death element, transitional mesh division and secondary development technology.The model considered temperature dependence of material property and the effect of the loss of heat,including convection and radiation on the temperature field.Then numerical simulation of EH36 temperature field was made and experimental verification of heating cycles was also made.The results show that the temperature of the weld pool rapidly rises above the melting point of the material at the beginning of the welding.Then the weld zone achieves quasi-steady temperature fields at 2-3 s after welding.The cooling rate of the welding edge is higher than that of the weld zone because of the high thermal conductivity,which makes the maximum temperature of the welding process move into the center of weldment.It is no filler metal beside it when the third layer and first pass welded joint is welding so it is not easy to heat transfer for the material and the isotherm offsets.However, the third layer and second pass welded joint is welding with filler metal so it is beneficial for heat transfer,which makes the isotherm relative to the center of the heat source basically symmetry.All heating cycles experience four peak values and they gradually decrease because of the thermal conductivity.The experimental values of the heating cycles are in good agreement with the simulation.This will provide the basis for predicting the welding process and structure, property and residual stress of the weldment.