2219铝合金VPTIG焊接残余应力的数值分析

Numerical simulations of welding residual stresses in VPTIG-welded joints of the 2219 aluminum alloy

2219铝合金经过焊接后出现了严重的软化,为了阐明焊后软化对焊接残余应力计算精度的影响,采用热-弹-塑性有限元计算方法模拟了2219铝合金平板变极性惰性气体保护对接单道焊时的温度场和应力场,并考虑了加工硬化和退火效应的影响。结果表明:软化现象对焊接残余应力的计算结果有显著影响,不考虑焊后软化时会高估焊缝区及其附近的残余应力水平。通过对比计算结果与实验测量结果可知,综合考虑加工硬化、退火效应及接头软化的情况下,数值模拟结果与实测结果吻合较好,说明该数值模拟方法具有较高的计算精度。

2219 aluminum alloy welded joints have significantly reduced strength because of the softening during welding. The influence of joint softening on the welding residual stress was studied using the thermal elastic plastic finite element method （T-E-P FEM） to predict the welding temperature and residual stresses in a variable polarity tungsten inert gas （VPTIG） welded 2219 aluminum alloy joint. The influences of work hardening and the annealing were also examined. The simulations show that joint softening significantly influences the longitudinal residual stress and that the longitudinal residual stresses in the weld zone and nearby regions are overestimated when the joint softening is not taken into account. Comparison of the simulated results with measured data shows that when work hardening, annealing and joint softening are considered, the residual stresses predicted by the T-E-P FEM agree well with the measured data, which indicates that this approach can accurately predict residual welding stresses in 2219 aluminum alloy.