激光冲击消除焊接残余应力

对现有焊接残余应力的理论进行分析,讨论激光冲击处理消除焊接残余应力的可行性,认为短脉冲高峰值功率密度的激光冲击焊接接头产生的等离子体冲击波,可使焊接接头表面产生塑性应变,能有效消除焊接残余拉应力。文章设计了激光冲击强化12Cr2Ni4A钢焊接接头试验,通过选择不同焊接材料和焊接方式,设计了4种焊接状态,分别进行激光冲击强化。试验结果表明,激光冲击强化均能消除氩弧焊和等离子焊等焊接方式的焊接残余拉应力,改善焊接接头表面的力学分布,在选用NAK80焊材和等离子体焊方式时,形成的残余压应力幅值高达884MPa,极大提升了焊接接头的力学性能。

Eliminating welding residual stress by laser shock

The different viewpoints of welding residual stress were analyzed and the feasibility of erasing the welding residual stress by laser shock was discussed.Nanosecond pulse and 1000MW laser irradiation on the materials could induce the high pressure plasma shock wave and generate the plastic deformation,thus it could effectively eliminate welding residual tensile stress.The experiments of 12Cr2Ni4A steel welding joints processed with different welding materials and methods under laser shock processing(LSP) were designed,and conducted through four different welding statuses.Results showed that laser shock could erase the welding residual tensile stress caused by argon arc welding and plasma welding,and also could improve the distribution of force on the surface of welding joints.Using NAK80 welding material and plasma welding,the compression stress reached to 848MPa,which led to a sharp increase of mechanical properties of the weld joint.