厚板对接多道焊温度场的三维数值模拟

采用三维有限元法模拟厚板对接多道焊的温度场分布.计算过程中考虑了温度对材料相变和热物理特性的影响,采用了“生死单元“的技术,实现了模拟过程中焊接材料的逐步填充.同时采用热电偶实时测量厚板对接多道焊的温度场.结果表明,温度场计算值与试验测量值十分吻合,为全焊接阀体球阀的阀体焊接工艺参数的确定提供了重要的手段;同时从温度场变化趋势可以得出,为了控制多道焊的焊接温度,在保证焊接质量的前提下,应尽量减小前几道焊接线能量.

The Three Dimensional Simulation of Temperature Distribution of Thick Plate Multipass Welding

Three-dimensional finite element method was used to analyze the temperature distribution of thick plate multipass welding.During the calculation,enthalpy and temperature dependence of material properties were taken into consideration. Birth and death of elements was used to simulate the filling of welding material step by step.At the same time,temperature distribution of thick plate multipass welding was measured with thermocouple.The results show that the values calculated of temperature distribution are close to the values measured,which provides an important method for the confirmation of welding process parameters of full welded ball valve.According to the change trend of temperature field,in order to control multipass welding temperature,the heat input of the first several passes must be decreased under assuring welding quality.