等离子弧焊接熔池温度场的三维数值模拟

建立了运动等离子弧作用下焊接温度场的三维瞬态数值分析模型，以分析等离子弧焊熔池温度分布情况以及焊接电流、焊接速度等焊接工艺参数对其影响情况．综合考虑了液态金属的对流传热和熔池外部的固体导热、材料热物理性能参数随温度的变化、焊件表面的散热以及熔化／凝固相变潜热等对熔池温度场的影响．采用三维锥体热源对小孔型等离子弧焊接过程进行了流体动力学和传热分析，利用ANSYS有限元软件求解所建立的模型，得到了等离子弧焊接过程中温度场的变化情况．模拟结果表明，随焊接电流的增大和焊接速度的减小，熔池体积增加，熔宽和热影响区都增大．试验结果验证了所建立模型的正确性和数值求解方法的可靠性．

3-D Numerical Simulation of Temperature Field in Moltenpool of Plasma Arc Welding

A model of plasma arc welding(PAW) with a moving arc was developed to study the temperature field and the effects of welding current and welding speed,etc on it.Both convection heat transfer of the melted metal and heat conduction of solid metal were considered,regarding the solid metal as liquid with large viscosity.The variation of thermophysical parameters of material with temperature,the loss of heat,including convection and radiation,and the latent heat of phase transformation was also taken into account.Welding heat source was presumed to be 3-D conical heat source.The model was solved by the ANSYS software.The temperature distribution during the whole welding process was obtained.The simulation results show that weld pool width and heat-affected zone increase with the increase of welding current and the decrease of welding speed.The reliability of the model is validated by experimental results.