Comparative analysis of structural and mechanical properties of duplex stainless steel (DSS) weldments prepared by flux core arc welding and shielded metal arch welding processes

Abstract

Duplex stainless steel (DSS) possesses wide range of useful metallographic and mechanical properties; hence the material has been used in different forms of application namely in chloride present environments such as desalination plants and cooling water services such as conventional and nuclear power stations. However, this material has its limitations as it's susceptible to cracking particularly stress corrosion cracking or pitting corrosion and can exhibit poor metallurgical properties such as microstructures and phase containing unbalanced proportions of ferrite and austenite. In this study, Flux Core Arc Welding (FCAW) is compared with Shielded Metal Arch Welding (SMAW) process, in terms of their effects on the structural and mechanical properties and performances of DSS weldments. Analysis of the microstructure and phases were carried out. Also, the tensile, microhardness, impact and fracture properties were determined with relevant techniques. The results indicated that SMAW and FCAW welding processes differentially influence the structural and mechanical properties of the DSS weldments, consisting of the part of base material, weld and the heat affected zone (HAZ). The weld prepared using the SMAW process exhibited superior hardness characteristics at 309 HV and achieved the highest impact energy absorption of 145.92 J. In contrast, the FCAW prepared weldment exhibited the highest tensile strength, reaching 282.30 kN maximum load.