Enhancement of Microstructural and Mechanical Properties of Ultrasonic Vibration-Assisted Cold Metal Transfer Welding of 304 Stainless Steel

Ultrasonic vibrations aid fabrication techniques that enhance the structural efficiency of manufactured products. It gives an appreciable advantage in the microstructural and mechanical properties of products. In this paper, Ultrasonic assisted Cold Metal Transfer Welding (U-CMT) technique used to join the AISI 304 stainless steel. The welded joints are analyzed using optical microscopy, SEM, and XRD. The microhardness, tensile, and residual testing of the U-CMT welded joint is evaluated and compared with CMT welded joint. The microhardness and tensile results of the U-CMT welded joint show considerable improvement in their mechanical properties due to the refinement of grains in the fusion region, which is produced by ultrasonic vibrations. With vibration welded samples, results show a reduction of residual stresses compared to those without vibration welded samples. This study chose two different ultrasonic vibrational amplitude 50 and 99 µm and three different welding currents, 85, 90, and 95A. U-CMT welded joint prepared with a welding current of 95A and ultrasonic vibrational amplitude of 99 µm shows 100% weld joint efficiency.