Electrochemical corrosion behavior and microstructural characteristics of electron beam welded UNS S32205 duplex stainless steel

Abstract

Different electrochemical techniques were used to study the corrosion behavior of UNS S32205 duplex stainless steel (DSS) welded autogenously using a single‐pass by electron beam welding process, supplemented by microstructural characterization. Furthermore, a comparative study was also performed between multipass gas tungsten arc (GTA)‐welded and EB‐welded DSS for their microstructure and corrosion behavior. The differences in weld thermal cycle and chemical composition influenced the fusion zone microstructure of both the welds and eventually their corrosion properties. The general corrosion resistance of the EB weld was lower than the base metal and higher than the GTA weld despite its weld zone being characterized by a relatively unbalanced phase ratio (α/γ) in comparison to the GTA weld. However, the EB weld showed relatively higher susceptibility to pitting corrosion than the base metal and GTA weld due to its poor repassivation characteristics and poor resistance to pit growth.