摘要
通过对6005A铝合金型材MIG焊搭接接头进行带有预加速试验的微观组织分析和力学性能测试,研究不同应力级下的高周交变应力加载对焊接接头力学性能和微观组织的影响。结果表明:未经过加速试验试样的抗拉强度平均值为204.836 3 MPa;经过60%疲劳极限加速试验试样的抗拉强度平均值为204.028 2 MPa,断裂位置均为HAZ;经过90%疲劳极限加速试验试样的抗拉强度平均值为188.701 6 MPa;未加速疲劳试样焊缝中心硬度平均值为69.30 HV,60%加速疲劳试样焊缝中心的硬度平均值为70.07 HV,90%疲劳试样焊缝中心硬度平均值为66.45 HV。未经过加速试验试样和经过60%疲劳极限加速试验试样的冲击功平均值均为6.67 J;经过90%疲劳极限加速试验试样的冲击功平均值为6 J。性能变化的原因在于晶粒的形态尺寸的改变,加速试验中所加载荷较高时,焊接接头的晶粒被拉长,产生合并现象,晶界面积减小,晶界储能减小。
n this paper,the effects of high cycle alternating stress loading on mechanical properties and microstructures of overlap joints of 6005 A aluminium alloy profile by MIG welding with pre-accelerated test were studied. The results show that the average tensile strength of the specimens without accelerated test is 204.836 3 MPa. The average tensile strength of the specimens with 60% fatigue limit accelerated test is 204.028 2 MPa and the fracture location is HAZ. The average tensile strength of the specimens with 90% fatigue limit accelerated test is 188.701 6 MPa;and the weld of the specimens without accelerated fatigue limit accelerated test is 188.701 6 Ma. The average hardness of the core is 69.30 HV,the average hardness of the weld center of 60% accelerated fatigue specimens is70.07 HV,and the average hardness of the weld center of 90% fatigue specimens is 66.45 HV. The average impact energy of the samples without accelerated test and 60% fatigue limit accelerated test is 6.67 J,and that of the samples with 90% fatigue limit accelerated test is 6 J. The reason for the change of properties lies in the change of grain size and morphology. When the load is higher in accelerated test,the grain of welded joint is elongated,resulting in coalescence,the decrease of grain boundary area and the decrease of grain boundary energy storage.
作者
张锦华
范乐天
杨帅
ZHANG Jinhua;FAN Letian;YANG Shuai(Zhongche Tangshan Locomotive and Rolling Stock Co.,Ltd.,Tangshan 063035,China)
出处
《电焊机》
2019年第3期72-78,共7页
Electric Welding Machine
