Behavior of a superaustenitic stainless steel weld cladding deposited by the gas metal arc welding process

Abstract

The performance of a superaustenitic stainless steel weld metal containing 6%Mo deposited by the GMAW process was studied. Multipass welding by the GMAW process with three layers was performed on a carbon steel plate with average heat input of 0.8 kJ/mm. After welding, microstructure characterization by scanning electron microscopy and electron backscattering diffraction, and corrosion performance by cyclic polarization and potentiostatic tests to determine the pitting potential and critical pitting temperature were performed on samples extracted at 3 mm from the fusion line, the minimum thickness required. The weld metal containing 6%Mo showed a microstructure consisting of an austenitic matrix with a volume fraction of Chi and Laves phases inferior to 1% and a PREN value higher than 40 at the dendrite core. As a consequence, similar pitting potential and critical pitting temperature compared to original alloys containing 6%Mo were obtained. Thus, superaustenitic stainless steel weld metals containing 6%Mo have the potential to be suggested as an alternative for weld claddings in the oil and gas industry.