Ar-Ar变动送气条件下5A03铝合金TIG焊焊缝组织和性能  

Research on the weld performance of 5A03 aluminum alloy with variable gas TIG welding

作　　者：李继超 戴鸿滨[1] LI Jichao;DAI Hongbin(School of Materials Science and Engineering,Harbin University of Science and Technology,Harbin,150040,China)

机构地区：[1]哈尔滨理工大学,哈尔滨150040

出　　处：《焊接学报》2021年第10期67-72,I0005,I0006,共8页Transactions of The China Welding Institution

基　　金：黑龙江省自然基金(LH2019E057)。

摘　　要：5A03铝合金在传统TIG焊接过程中,焊缝易存在强度低、晶粒粗大的问题.为了改善5A03铝合金焊缝性能,在传统TIG焊接方法的基础上,改变保护气的送给方式,针对板厚为2.5 mm的5A03铝合金板进行对接焊接试验.焊后分别对焊缝进行拉伸试验、断口形貌分析、偏振光电子显微镜和扫描电镜的观察及电化学分析.结果表明,与传统焊获得的焊缝相比,1 Hz变动送气TIG焊所获得的焊缝抗拉强度提高了18.5 MPa,提升强度约为传统焊缝强度的10%,两种焊缝的断裂形式均为塑性断裂.对比焊缝晶粒尺寸发现,1 Hz变动送气条件下获得的焊缝晶粒更加细小,并且β相Al8Mg5在铝基体上呈现弥散形态分布;电化学结果分析表明,变动送气TIG焊焊缝自腐蚀电流密度增大,容抗弧半径减小,自腐蚀电位负移0.04 V,传统焊焊缝的耐蚀性较好.In the traditional TIG welding process of 5A03 aluminum alloy, the weld is prone to have the problems of low strength and coarse grains. In order to improve the performance of the 5A03 aluminum alloy weld, on the basis of the traditional TIG welding method, by changing the shielding gas supply Method of butt welding experiment on 5A03 aluminum alloy plate with plate thickness of 2.5 mm. After welding, the welds were subjected to tensile test, fracture morphology analysis, observation with polarized light electron microscope and scanning electron microscope, and electrochemical analysis. The results showed that: compared with the welds obtained by traditional welding, the results obtained by 1 Hz variable gas TIG welding The tensile strength of the weld is increased by 18.5 MPa, and the strength is about 10% of that of the traditional weld. The fracture modes of the two welds are plastic fracture. Comparing the weld grain size,it is found that the weld grains obtained under the 1 Hz variable air supply condition are smaller, and the β-phase Al8Mg5 presents a dispersed morphology distribution on the aluminum substrate;the electrochemical results analysis shows that the self-corrosion current density of the variable air TIG weld Increased, the capacitive arc radius decreases, and the selfcorrosion potential moves to the negative half axis by 0.04 V.The corrosion resistance of the traditional welding seam is better.

关 键 词：5A03铝合金 Ar-Ar交替 TIG焊 Β相 耐蚀性 

分 类 号：TG444[金属学及工艺—焊接]