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

Paper Number: 123088

123088 - Evaluation of Mechanical and Corrosion Properties of Stainless-Steel Weldment Using Gmaw Modified Waveform Short Circuit Welding Process Without Backing Gas 

This paper presents mechanical and corrosion resistance properties of stainless steel weldment deposited using GMAW modified waveform short circuit welding process without backing gas, also referred to in this paper as No-Backing Gas (NBG) welding. Obtained data has been established using 316LSi stainless steel filler metal on 304L stainless steel base metal. Test work included a baseline sample, deposited using GTAW welding process for root pass back purged with inert gas, as this has traditionally been the industry-wide best practice for welding stainless steel pipe to minimize or prevent the weldment internal surface contamination and oxidation. NBG test samples were welded using GMAW-P and FCAW welding processes for fill and cap passes. Baseline GTAW sample was welded using GTAW and FCAW welding processed for fill and cap passes. Test work included ASME Section IX required tests, Charpy impact test, ferrite test, macrograph and microstructure examination, hardness examination, corrosion test ASTM A262 Practice C and corrosion immersion test ASTM G48 Modified Method E. The obtained results are assessed for cryogenic temperature application requirements of ASME B31.3 Process Piping Code and for corrosive service application. The paper also discusses the challenges associated with ASTM G48 Method E for testing of 304 stainless steel weldment and use of a modified G48 method fit-for-purpose to evaluate results.

 

Key words: Backing Gas, Corrosion, GMAW, GTAW, Modified Waveform Short Circuit, No-Backing Gas (NBG), Piping, Stainless Steel

Presenting Author: Dishoo Randhawa Fluor

Presenting Author Biography: Fluor Engineer

Authors:

Dishoo Randhawa Fluor
Jorge Penso Shell Projects and Technology
Shahab Soltaninia Fluor
Sivakumar Chiluvuri LNG Canada