局部外加载荷对TC4焊接纵向残余应力影响
Finite Element Analysis on TC4 Welding longitudinal residual stress affected by local external loading
张勇，綦秀玲
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作者单位：辽宁工程技术大学 材料科学与工程学院
中文关键字：局部外加载荷；焊接应力应变；有限元分析；TC4
英文关键字： local external loading ;the welding stress strain; finite element analysis ; TC4
中文摘要：TC4因其优良的力学性能和工艺性能而被广泛地使用，但是由于在焊缝及近缝区的塑性压缩变形导致焊接件中存在绝对值较大的焊接纵向残余压应力和焊接变形，其根本原因在于纵向焊接残余压应力超过了TC4薄板件的临界失稳应力。为了减少焊接变形及其所导致的附加弯矩，采用随焊冲击旋转挤压的方式对焊缝及近缝区进行塑性延展。其中跟随焊接热源移动的外加载荷将对焊接过程中的应力应变过程产生影响。采用有限元方法分析局部外加载荷对焊接残余应力及焊接瞬态应力应变的演化过程的作用，分析结果说明在外加载荷的作用下产生了塑性延展，降低了焊接残余应力，从根本上消除了导致焊接变形的因素。
英文摘要： Because of the excellent mechanical and technological properties, the alloy of TC4 is widely used. However, the the plastic compression deformation existed in the weld bead and near weld zone caused a larger absolute value of the longitudinal welding residual stress and distortion. The large welding distortion is produced by the longitudinal welding residual stress that exceeds the critical buckling stress of TC4 thin plate. In order to reduce the distortion and additional moment, the technology of welding with impacting rotation is utilized to generate plastic extension of the weld bead and near weld zone. The external local load should move with welding torch, and can change the development of thermal transient stress and strain in the welding process. Therefore, finite element analysis is used to analyze the role of the local loading on the transient stress and welding residual stress, the results show the welding residual stress is lowered by the plastic extension of the welding bead and near weld zone, the effect fundamentally eliminate the factors causing welding deformation.