Welding parameters optimization and mechanical properties analysis of PVPPA welded high-strength aluminum alloy

The welding process of 7075 aluminum alloy with a thickness of 10mm was carried out by PVPPAW. The influence of welding current and plasma gas flow rate on weld forming coefficient was studied. The optimum welding parameters were determined and the well-formed welds were obtained. The mechanical properties of the well-formed welded joints were analyzed. The results shown that the weld forming coefficient initially decreased and then increased with the increase of welding current. While the plasma gas flow rate increased, the weld forming coefficient gradually decreased. The better weld forming coefficient range is 1.1 ~ 1.3. Compared with the plasma gas flow rate, the welding current has greater influence on weld formation. The satisfying weld appearance can be achieved under the pulse welding current of 250 A/290 A, the plasma gas flow rate of 2.0 L/min. The welding quality is good under the optimum welding parameters, and the tensile strength of the weld reached 397.9 MPa, which is nearly 67.5% of that of the base metal. The weld area exhibited the dendrite microstructure.