Effect of TIG and activated flux TIG welding processes on weld bead geometry, microstructure, and hardness of SAF 2507 grade super duplex stainless steel joints

Abstract

Tungsten inert gas (TIG) welding is frequently used to fabricate super duplex stainless steel weldments due to its superior mechanical qualities and attractive appearance in contrast with other arc welding techniques. The broad use of TIG welding remains constrained despite all of its advantages. Thus, the process of activated flux tungsten inert gas (A-TIG) welding is created. In the current study, ATIG welding with different oxide fluxes is used to execute bead-on-plate welding on 6 mm thick super duplex (SS) SAF 2507 grade. The TIG and ATIG processes are used for bead-on-plate welding, and the macrostructure, microstructure, and mechanical features of super DSS weld beads are analysed. When different oxide fluxes are used, the A-TIG technique achieves a greater depth of penetration and a narrower weld bead width than the standard TIG process. SiO2 flux with ATIG welding gives the highest depth of penetration (5.42 mm) among all other fluxes used. Also, A-TIG welding using SiO2 flux has a finer grain structure and a higher hardness value than other fluxes. The primary microstructure in the A-TIG weld zone was austenitic, but delta ferrite was still present.