Effect of Pulsed Current for Autogenous TIG Welding of AISI 304 Stainless Steel

Abstract

Tungsten Inert gas (TIG) welding is an arc welding process which produces reliable and high quality weld joint. However conventional TIG welding has certain limitation like low power density and large weld bead along with high residual stress. In the present work, prior to actual welding, welding simulation was performed by ANSYS 15 to obtain the heat energy range required for melting of 3 mm SS 304 plate. Conventional Autogenous TIG welding has been performed on 3 mm thick SS304 stainless steel without using any filler material with different values of welding current. Pulsed Autogenous TIG welding has also been performed with different value of pulse frequencies. Pulse frequency increases the power density or concentration of energy due to arc shrinkage which ultimately leads to the higher melt pool depth and narrower weld width. Effect of pulse current also cause refinement of the grain as compared to constant current welding, which leads to the lower residual stress and improved mechanical properties.