脉冲频率对铝合金TIG焊接接头组织和力学性能的影响  

Effect of pulse frequency on microstructure and mechanical properties of welded joints in TIG welding for aluminum alloy

作　　者：王悦[1] 

机构地区：[1]南京化工职业技术学院,江苏南京210048

出　　处：《电焊机》2015年第9期110-112,共3页Electric Welding Machine

基　　金：江苏省教育厅高校科研成果产业化推进项目(JHB2012-66)

摘　　要：以7075铝合金为研究对象进行钨极氩弧焊接,通过金相显微镜、扫描电镜、显微硬度、抗拉强度等试验手段,研究脉冲频率对焊接接头组织和性能的影响。结果表明,当脉冲频率较小时,焊缝熔滴相对独立,随着脉冲频率增加,熔滴尺寸减小且数量增多。熔合区晶粒尺寸随脉冲频率增加而减小。铝合金TIG焊接接头母材显微硬度值最大,热影响区显微硬度值最小。脉冲频率越大,熔合区最大显微硬度值越高。随着脉冲频率的增加,铝合金焊接接头抗拉强度先增加后减小,脉冲频率40 Hz时达到母材95%。The tungsten inert gas arc welding is used for 7075 aluminum alloy and the effect of pulse frequency on the microstructure and mechanical properties of welded joints is studied through metallographic microscope,scanning electron microscope, microhardness and tensile strength tests.The results show that when the pulse frequency is small,the weld droplets are relatively independent,and as the pulse frequency increases,the droplets decrease in size and increase in number.The grain size of fusion zone reduces as the pulse frequency enhances.There is the maximum microhardness of the base metal of the welded joints in TIG welding for Al alloy,and the minimum microhardness of the heat affected zone.The greater pulse frequency is, the higher microhardness of fusion zone is.As the pulse frequency increases the tensile strength of aluminum alloy welded joints increases early and then decreases.The tensile strength of base metal reaches 95% when the pulse frequency is 40 Hz.

关 键 词：7075铝合金 钨极氩弧焊 脉冲频率 抗拉强度 

分 类 号：TG457.14[金属学及工艺—焊接]