能量配比对铝合金激光-MIG复合焊接残余应力的影响  

Effect of energy ration on residual stresses in laser-MIG hybrid welding of aluminum alloys

作　　者：张鑫源 孙振邦[1] Zhang Xinyuan;Sun Zhenbang(Inner Mongolia University of Technology,Hohhot 010051,China)

机构地区：[1]内蒙古工业大学,呼和浩特010051

出　　处：《焊接》2024年第6期47-53,共7页Welding & Joining

基　　金：2023年校级“大学生创新创业训练计划”项目(2023043002)。

摘　　要：【目的】旨在探究不同能量配比下激光−MIG复合焊接7075铝合金的残余应力分布规律及机理。【方法】在焊接过程中对工件不同位置的焊接热循环进行了测量,焊后使用X射线衍射仪测量了激光−MIG复合焊接接头残余应力分布,分析了不同能量配比下接头残余应力的变化规律。【结果】结果表明,当总热输入不变时,随着激光功率增加及MIG功率减小,焊接穿透能力增强,焊缝熔深逐渐增加,熔宽逐渐减小;且当能量配比系数过大时,焊缝成形质量下降。残余应力在垂直于焊缝方向上整体呈现双峰分布,在焊缝区附近呈现拉应力,在母材区呈现压应力;在平行焊缝方向,残余应力表现为“压—拉—压”趋势。【结论】由于激光能量更为集中,热影响区峰值温度随能量配比系数的增加呈现明显的上升趋势,故而随着激光功率占比的增加,形成较高的温度梯度,导致集中受热区域的残余应力增大;同时,由于MIG功率占比的减小,焊缝及热影响区以外区域残余应力呈现明显的减小趋势。[Objective]The purpose was to investigate residual stress distribution law and mechanism of laser-MIG hybrid welding of 7075 aluminum alloy under different energy ratios.[Methods]Welding heat cycle at different positions of workpiece was measured in the welding process,residual stress distribution of laser-MIG hybrid welded joints was measured by X-ray diffractometer after welding,and change rule of residual stress of welded joints under different energy ratios was analyzed.[Results]The results showed that when the total heat input was unchanged,with the increase of laser power and the decrease of MIG power,welding penetration ability was enhanced,penetration of weld gradually increased,and width of weld gradually decreased.When energy ratio coefficient was too large,quality of weld formation decreased.Residual stress showed overall bimodal distribution in the direction perpendicular to weld,tensile stress presented near the weld area,and compressive stress presented in the base material area.In the direction parallel to weld,residual stress manifested a“compression-pull-pressure”trend.[Conclusion]Because laser energy was more concentrated,peak temperature of heat-affected zone showed an obvious upward trend with the increase of energy ratio coefficient.Therefore,with the increase of laser power ratio,a higher temperature gradient was formed,which led to the increase of residual stress in the concentrated heating area.At the same time,due to the reduction of MIG power ratio,residual stresses in the weld and the area outside heat affected zone showed a significant decreasing trend.

关 键 词：高强铝合金 激光−MIG 能量配比 残余应力 

分 类 号：TG442[金属学及工艺—焊接]