Welding Investigation on GMAW−Cold Metal Transfer of AISI 201LN for Superior Weld Quality

Abstract

Austenitic stainless steel of AISI 201LN grade has found applications in liquefied natural gas tanks and cryogenic components. They are fabricated using gas tungsten arc welding (GTAW), but weld speed is low due to manual operation. This work aims welding investigation on AISI 201LN Gr. steel with a new hybrid welding approach (i.e., gas metal arc welding [GMAW] combined cold metal transfer [CMT]) for obtaining superior weld quality. Weld experiments were carried out at different welding speed, for example, 300, 400, 600, and 900 mm/min, to study weld quality and its mechanical properties. The microstructural examination of test coupons at higher welding speed shows finer structure in heat-affected zone as well as on weld metal. It was observed that the weld coupon having low heat input (at high weld speed) has maximum tensile strength. Scanning electron microscope analysis shows finer dimples at higher welding speed confirming ductile mode of fracture.