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采用双椭球热源模型建立叶轮TIG焊接的移动热源模型,以计算得到的温度历史作为热载荷,计算焊缝附近的残余应力分布,通过对比已有的文献实验数据以验证模型的有效性。进一步建立叶轮残余应力和残余变形的计算模型,分析焊接温度历史、叶轮应力和变形历史之间的内在联系,研究焊接参数和叶轮参数对焊后残余应力和残余变形的影响规律。分析结果表明:在叶轮叶片焊接时,获得的热应力随焊接温度的增加而增加,当焊接温度达到峰值时,热应力滞后几秒达到最大值;随着叶片厚度的增加,焊接变形略有减小,远离焊缝位置的叶片残余应力随叶片板厚增加而减小,同时叶片的残余应力和变形与叶片和叶轮的刚度比有关。
The dual-ellipsoid heat source model is used to establish the moving heat source model of the impeller TIG welding. The calculated temperature history is used as the thermal load to calculate the residual stress distribution near the weld. The validity of the model is verified by comparing with the existing experimental data. The calculation model of residual stress and residual deformation of impeller is further established. The relationship between welding temperature history, impeller stress and deformation history is analyzed. The influence of welding parameters and impeller parameters on residual stress and residual deformation after welding is studied. The results show that the thermal stress increases with the increase of the welding temperature. When the welding temperature reaches the peak value, the thermal stress lags a few seconds and reaches the maximum. With the increase of the blade thickness, the welding deformation is slightly reduced Small, away from the weld position of the blade residual stress decreases with the blade thickness increases, while the blade residual stress and deformation and blade and impeller stiffness ratio related.