坡口形式对双金属复合板多层多道焊接头残余应力演变的影响

Study of Influences of Groove Type on Welding Residual Stress Evolution in Bimetallic Clad Plate Joints during Multi-layer and Multi-pass Welding

采用TIG焊制备了13 mm厚Incoloy825/X52双金属复合板的对接接头,采用数值模拟与试验手段相结合的方法,分析了不同坡口形式对复合板接头焊接残余应力分布的影响,揭示了双金属复合板多层多道焊过程中残余应力的演变特征。结果表明:对于双金属复合板而言,复合型及V型坡口接头内部最高应力集中区域均位于过渡层内,沿水平方向呈现长条状分布,坡口形式的变化对于接头内部和表面应力的分布特征及峰值没有明显影响;从残余应力的产生和演变过程来看,只有当复合板接头的基层、过渡层和复层都焊接完成后,过渡层内才会产生最高应力集中区域;此外,最终焊道对复合板接头的应力分布起着决定性作用,会对最终应力状态产生很强的牵引作用,使其呈现偏离试板中心线的不对称分布。

The 13 mm-thick Incoloy825/X52 bimetallic clad plates were prepared by TIG welding.Both finite element method and experimental means were conduct to study the residual stress distribution characteristics during multi-layer and multi-pass welding of plates with different groove types.The results show that for the bimetallic composite plate,the highest stress concentration area is always located at transition seam layer with a long strip distribution profile no matter which type of groove is applied.The changes of groove types have limited effects on the profile and peak value of both internal and surficial high residual stress region.The evolution of residual stress inside the joints shows that the highest stress concentration region in transition layer will not generate until all base,transition and flyer seam layers welding are finished.Besides,the final weld plays a decisive role in the formation of final residual stress state.It will have a strong“pulling”effect on residual stress distribution and make the final stress distribute asymmetrically.