Session: MF-20-01 Material Quality and Failure Analysis-1

Paper Number: 154098

154098 - Super Duplex Stainless Steel Narrow Gap Welding with Machine GTAW 

Abstract: 

Duplex and super duplex stainless steels are widely used in various industries because of its good corrosion resistance, high strength and good low temperature toughness.  However, with the increased applications of duplex and super duplex stainless steels, there are also many reported failures for the in-service welds due to undesirable phase balance and/or σ-phase precipitation etc.

In this paper, guidance and recommendations for achieving high quality super duplex stainless steel welding are provided by detailed analysis of the procedure qualification test results.  

Welding procedure qualifications on heavy wall super duplex pipe using mechanized GTAW process were performed in both 2G and 5G welding positions. Non-destructive examination (NDE), 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 and microstructure and intermetallic phases, this paper provides insight into the effects of welding process variables on mechanical properties and weld quality. Challenges on heavy wall super duplex welding were addressed. Guidance and recommendations on welding process selection,  joint design, welding parameters and welding techniques are provided.

Presenting Author: Dongmei Sun Liburdi Group

Presenting Author Biography: Dongmei Sun is a senior welding engineer at Liburdi GAPCO, a field service division of Liburdi Group of Companies. Dongmei has extensive experience in welding, material, quality control, construction codes and standards; and has been providing welding engineer supports and consultations for nuclear, marine and petrochemical industries.

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