Effect of Post-Weld Heat Treatment on the Corrosion Resistance of Super Austenitic Stainless Steel

Abstract

Seaborne transportation by merchant vessels amounts to more than 90% of the world’s trade volume and it represents about 20% to 30% of the materials generated by the combustion of the total fuel. The International Maritime Organization (IMO) has enforced the use of 0.5% or less low-sulfur fuel oil when operation in all since 2020, and the installation of a scrubber is considered the most realistic alternative in compliance with IMO’s new regulation. However, the desulfurization process unavoidably creates a corrosive environment, and corrosion from it is mainly concentrated on welded materials. To solve the corrosion problem in that area, post-weld heat treatment was applied on Super Austenitic Stainless Steel (UNS N08031) which is commonly used for scrubbers. Upon heat treatment at 1,160 °C or at a higher temperature after welding, microsegregation of welds and base metals was dissolved. As a result, elements were distributed equally and the corrosion resistance increased due to the formation of a uniform oxide film.