能量配比对6 mm 7A52铝合金板材VPPA-MIG复合焊接残余应力分布的影响

Effect of energy proportion on residual stress distribution of 6 mm 7A52 aluminum alloy plates in VPPA-MIG hybrid welding

VPPA-MIG复合焊接的热源由VPPA和MIG两种电弧热源混合而成,该焊接方法集合了MIG焊接效率高、参数区间宽以及VPPA焊接能量集中、穿透深度大等优点,能够实现不同厚度铝合金板材的高效率和高质量焊接。在铝合金板材VPPA-MIG复合焊接过程中,VPPA与MIG两种电弧不同能量配比会影响焊后接头的残余应力分布。以6 mm厚7A52铝合金板材为试验材料,设置VPPA电弧能量配比不同的焊接参数进行VPPA-MIG复合焊接试验,焊后采用钻孔法测试并分析了接头残余应力分布及峰值大小。结果表明,复合焊接接头的熔合区和热影响区出现拉应力,母材区出现压应力。在复合焊接热源总能量不变的情况下,残余应力峰值随VPPA电弧能量配比的增加而增大,且当VPPA电弧能量配比从35%增大至40%时,可以获得成形效果良好的复合焊缝,横向残余应力峰值不超过73 MPa,纵向残余应力峰值不超过232 MPa,不会出现过大的残余应力峰值。与单MIG焊接相比,VPPA-MIG复合焊的残余应力峰值比单MIG焊大,而高应力区要比单MIG焊窄。

The heat source of VPPA-MIG hybrid welding consists of a mixture of two arc heat sources,VPPA and MIG,and the welding method combines the advantages of high efficiency and wide parameter range of MIG welding and concentrated energy and large penetration depth of VPPA welding,which is capable of realizing high-efficiency and high-quality welding of different thicknesses of aluminum alloy plates.In the aluminum alloy plate VPPA-MIG composite welding process,the different energy proportion of VPPA and MIG arcs will affect the residual stress distribution in the welded joint.Taking 6 mm thick 7A52 aluminum alloy plate as the test material,different welding parameters of VPPA arc energy proportion were set for VPPA-MIG composite welding test,and the residual stress distribution and peak size of the joint were tested and analyzed by drilling method after welding.The results show that tensile stress appears in the fusion zone and heat affected zone of hybrid welded joint,while compressive stress appears in the base metal zone.Under the condition that the total energy of the hybrid welding heat source is constant,the peak magnitude of residual stress increases with the increase of the proportion of VPPA arc energy.When the proportions of VPPA arc energy increase from 35%to 40%,the hybrid weld with satisfied forming effect can be obtained without excessive peak magnitude of residual stress.The peak magnitude of transverse residual stress does not exceed 73 MPa,and the peak magnitude of longitudinal residual stress does not exceed 232 MPa.Compared with single MIG welding,the peak magnitude of residual stress of VPPA-MIG hybrid welding is larger,and the high stress zone is narrower than that of single MIG welding.