Session: MF-24-01 Materials and Fabrication for Refining - 1

Paper Number: 106333

106333 - Pitting Corrosion Resistance of No Backing Gas (Nbg) Stainless Steel Welds 

Stainless steel welds for service applications in corrosive environments typically require the use of an inert backing gas in order to minimize or prevent root pass contamination and oxidation. This adds significant cost and complexity to the welding of stainless steel due to access restrictions, personnel safety, and/or economic factors. In this study, no backing gas welds (NBG) were made on Type 304L austenitic stainless steel with Type 316 filler metal. Open gap root welds was performed using three different waveform controlled gas metal arc welding (GMAW) processes and one flux-cored gas tungsten arc welding (GTAW) process. The fill and cap welds were made with either GMAW-P, GTAW or flux-cored GTAW process. We will present and discuss the pitting corrosion resistance of the NBG welds as compared to GTAW reference welds made with argon backing gas. A simple syringe cell setup was used for electrochemical corrosion testing. Cyclic potentiodynamic polarization (CPP) measurements based on ASTM G61 were performed locally on the backside surface heat-affected zone and root weld metal. The syringe cell approach enabled corrosion testing in a localized region on the metal surface and prevented crevice corrosion to form, which often interferes with the assessment of the critical pitting potential. Results from weld metal ferrite analysis and Charpy V-notch toughness testing will also be discussed.

Presenting Author: Claire Cary Ohio State University

Presenting Author Biography: Claire Cary is a second-year graduate student pursuing her M.S in Welding Engineering from The Ohio State University. Prior to her graduate work she also received her B.S in Welding Engineering from Ohio State University in 2021. Her research background consists of work studying impulse welding with a vaporizing foil actuator (VFA), characterization and metallurgical modelling of sulfur in dissimilar welds between Ni-base alloys and stainless steel, and most recently corrosion behavior of austenitic and duplex stainless steel. Beyond research she has experience with large-part manufacturing codes and standards, and welding wire formulation.

Authors:

Claire Cary Ohio State University
Jorge A. Penso Shell Global Solution (US) Inc., Houston
Narasi Sridhar The Ohio State University
Carolin Fink Ohio State University