端部结构三大梁焊缝气孔原因分析及解决措施  

Cause Analysis and Solution of Weld Blowhole in Three Girders of End Structure

作　　者：夏茂燕 许民 阳绪文 XIA Maoyan;XU Min;YANG Xuwen(Hunan Liancheng Rail Equipment Co.,Ltd.,Zhuzhou,Hunan 412001,China)

机构地区：[1]湖南联诚轨道装备有限公司,湖南株洲412001

出　　处：《自动化应用》2023年第5期20-23,共4页Automation Application

摘　　要：气孔是铝合金焊接中常见的缺陷之一,其会降低焊缝的致密性,削弱焊缝的有效截面积,从而降低焊缝的力学性能。本文通过分析环境温湿度、焊接工艺、自动焊接设备等因素,找出了造成铝合金车体底架端部结构三大梁焊缝密集型气孔的原因。通过逐一排查和试验分析,发现此密集型气孔是由于悬臂MIG自动焊接专机的气路系统密封性问题所导致的。由于自动焊专机焊接系统焊枪喷嘴处的保护气体流量过小,气体保护不足,致使焊缝产生密集型气孔。经测量发现,从气瓶到焊枪喷嘴的保护气流量发生了严重的衰减,衰减值高达13 L/min。针对此问题,改造自动焊专机原有气路系统,确保焊枪喷嘴处保护气体流量到达22 L/min,保护了电弧、金属熔滴、熔池和焊接区,有效控制了焊接气孔的产生。Porosity is one of the common defects in aluminum alloy welding.Porosity can reduce the density of weld,weaken the effective cross-sectional area of weld,and reduce the mechanical properties of weld.By analyzing the environmental temperature and humidity,welding technology,automatic welding equipment and other factors,this paper finds out the cause of aluminum alloy chassis end structure three girders weld-intensive porosity.After investigation and test analysis,it is found that the air hole is caused by the sealing problem of the air circuit system of the cantilever MIG automatic welding machine.The gas flow at the nozzle of welding torch of automatic welding machine is too small and the gas protection is not enough,which causes dense porosity in the weld.It was found that the flow rate of the protecting gas from the cylinder to the nozzle of the welding torch had a serious attenuation,and the attenuation value was as high as 13 L/min.In view of this problem,the original gas circuit system of automatic welding machine is reformed to ensure that the gas flow rate at the nozzle of welding torch reaches 22 L/min,so that it can effectively protect arc,metal droplet,molten pool and welding area,therefore,the welding porosity can be effectively controlled.

关 键 词：铝合金 气孔 自动焊专机 气路系统 

分 类 号：TG441.7[金属学及工艺—焊接]