预拉伸对船用气阀等离子堆焊残余应力影响的有限元分析

Finite element analysis of influence of pretension on residual stress in plasma surfacing welding of marine valve

基于ABAQUS有限元分析软件模拟了大型船用气阀在有预拉伸力和无预拉伸力情况下的等离子堆焊过程,通过二次开发热源模型,建立了多个生死单元分析步,实现焊料的逐步填充,考虑了不同材料性能参数随温度的变化。结果表明:预拉伸焊接法可以有效减小焊后残余应力,当预拉伸应力σp=20%σs时,效果最明显,焊缝区残余应力降低幅度达43%,同时,整个焊接件残余应力分布更为合理,应力梯度得到大幅改善,但是,在轴向焊缝处应力不减反增现象明显。最后对产生的缺陷进行分析,得到了优化的工艺参数,模拟结果与试验结果吻合较好。

Based on the ABAQUS finite element analysis software,the plasma surfacing welding process of large marine valves with and without pretension force was simulated. Through the secondary development of the heat source model,multiple birth-death element analysis steps were established to realize the gradual filling of solder,and the variation of different material performance parameters with temperature was considered. The results show that the pre-tensile welding method can effectively reduce the residual stress after welding. When the pre-tensile stress σp= 20%σ_s,the effect is the most obvious,and the residual stress in weld area decreases by 43%. At the same time,the residual stress distribution of the whole solder joint is more reasonable and the stress gradient is greatly improved. However,at the axial welding,the stress does not reduce but increases obviously. Finally,the defects were analyzed and the process parameters were optimized,the simulation results are in good agreement with the test results.