Effect of ER5356 Welding Wire on Microstructure and Mechanical Properties of 5083 Aluminum Alloy GTAW Welded Joint

Abstract

Automatic gas tungsten arc welding experiments of 5083 aluminum alloy were completed, to analyze the weld microstructure and mechanical properties. The influences of welding current, travel speed, frequency, and arc length on weld forming and mechanical properties were studied. When the welding current was 160 A, the travel speed was 380 mm/min, the frequency was 100 Hz, the arc length was 4 mm, and the maximum tensile strength of the welded joint was 296.9 MPa, which was 86.8% of the base metal’s tensile strength. The fracture elongation was 7.8%. No porosity was formed in the weld, but there were poor fusion problems. ER5356 welding wire can improve the problem of poor weld fusion and accommodate Mg element vaporization losses. When the wire feeding speed was 1200 mm/min, the tensile strength of the welded joint can be improved to 315.2 MPa, which was 92.2% of the base material’s tensile strength, and the fracture elongation was 8.5%. The tensile specimens fractured in the heat-affected zone. The fracture surface was characterized as plastic fracture. Specific strength of aluminum alloy is high, so aluminum alloys reduce the weight of the structure compared with steel structures. Aluminum alloys have a broad application prospect in aerospace, automotive, and marine industries based on their good corrosion resistance, low temperature resistance, good processability, and rich alloy system (Kuk et al. 2004; Wang & Zhang 2015; Canepa et al. 2018; Gaur et al. 2018; Qiang & Wang 2019). In recent years, to reduce the weight of the structure such as trimaran hull and improve speed, aluminum alloys have been more and more applied in shipbuilding. But there are many problems in the welding of aluminum alloy.