中厚板多层焊后焊层对焊缝纵向残余应力影响的数值分析

Numerical analysis of longitudinal residual stress during multi-layer welding

通过有限元方法对TIG焊中厚板对接接头进行了动态模拟,分析了后焊层对已焊层纵向焊接残余应力的影响,计算结果表明:后焊层对已焊层的温度和纵向残余应力的影响与板材的厚度存在着直接的关系,当板材的厚度不是很大时,后焊层的焊接热输入使已焊层的温度超过了相变温度,且由于温度过高使相邻后焊层与已焊层层间晶粒经历了熔化再结晶、重新形核长大的过程,使已焊层的温度重新回到较高温度,接近或达到熔点,后焊层对已焊层并没有起到热循环对残余应力场影响的作用,其纵向残余应力值基本没有变化。

Finite element method was employed to discuss the effect of the later welding layer on the former welding layer.The results show that the effect of later welding layer on the former welding layer is concerned with the thickness of plate and heat input of the later welding layer.If the thickness is not very large and the heat input of later welding layer is very large,the temperature of front welding layer reaches the phase transition temperature during later welding process.When the temperature of former welding layer reaches or is adjacent to the melting point,later welding does not play a relieving welding residual stress role to the former welding layer.