Improvement in the microstructural properties of super duplex and austenitic stainless steel dissimilar joints by incorporating Ni-based austenitic interlayer

Abstract

Tungsten inert gas welding (TIG) has remained a worldwide utilized welding technology in the industry to till date. Activated tungsten inert gas welding (ATIG) is also an advanced variant of TIG to enhance the penetration depth and reduce the width of the weld bead in single-pass compared to traditional TIG welding. The current study focuses on utilizing the Inconel interlayer approach to link dissimilar cold-rolled super duplex and austenitic stainless steels, which are mostly used in the offshore and marine industries. A systematic strategy is used to emphasize the studies conducted after using the ATIG interlayer procedure over the traditional TIG interlayer welding process. The research also studies and compares the microstructure, elemental mapping of the weld interface, phase identification and mechanical properties of dissimilar welded super duplex and austenitic steel samples. • ATIG welding approach for achieving single pass penetration of 6 mm thick plate with reduced weld heat input. • Without any weld defects such as weld porosity, undercut, overlap defect, and hot cracking a dissimilar welding of austenitic 202 and super duplex 32760 plates were successfully completed. • Microstructure evolution such as reduction in the width of heat affected zone, and reduction in the width of the unmixed zone was seen after using the ATIG interlayer weld technique. • Mechanisms such as reverse Marangoni and arc constriction in ATIG welding techniques could easily reduce parent metal loss in weld zones.