Super Duplex Stainless Steel Narrow Gap Welding With Machine GTAW

Welding qualification on heavy wall super duplex pipe using narrow gap machine GTAW process was performed and evaluated. Non-destructive testing (NDT), mechanical testing, metallurgical examination and corrosion test were conducted on the qualification coupons in accordance with applicable codes, standards and technical specifications. Optimization of joint design and welding parameters was also carried out to minimize welding shrinkage for the intended application. By detailed analysis of the mechanical properties, corrosion test weight loss, microstructure and intermetallic phases, this paper provides insight into the effects of welding process variables on mechanical properties and weld quality. Challenges on super duplex welding were addressed. Advantages in using narrow gap machine GTAW welding for achieving high quality heavy wall super duplex stainless steel welding were discussed.