An In-Depth Investigation of the Effects of Tungsten Inert Gas Welding Process Parameters on Hardness and Corrosion Resistance of 2205 DSS Weldments: New Design of Experiment Parametric Studies and Optimization

This study employs response surface methodology to examine and analyze how the Tungsten Inert Gas (TIG) welding process parameters, such as welding current (WC), welding speed (WS), and the use of N 2 with argon as shielding gas, impact the hardness and corrosion resistance of weldments made from 2205 duplex stainless steel (DSS). Duplex stainless steel DSS has equal amounts of ferrite and austenite phases, as well as alloying elements, which provide good mechanical properties and corrosion resistance. The welding process can affect the mechanical characteristics and resistance to corrosion of the weld zone and heat -affected zone of Duplex Stainless Steel (DSS) by changing the distribution of its two phases and causing thermal disturbance in the alloy. Therefore, in this work, an in-depth investigation of the effects of the above -mentioned parameters on the DSS quality has been performed. Results showed that increasing welding current while decreasing welding speed, which corresponds to the highest heat input, led to lower critical pitting potential and weld zone hardness but higher heat -affected zone hardness. The same results were obtained for decreasing welding current while increasing welding speed, which corresponds to the lowest heat input. However, when a small percentage of N 2 was added to argon shielding gas, it increased the critical pitting potential and decreased the hardness in welds and heat -affected zones. According to the response surface methodology (RSM) planned experimental results, the optimal welding conditions were a welding current of 175A, welding speed of 170 mm/min, and 10% N 2 with argon as shielding gas. These conditions maximized the critical pitting potential up to 318 mV and optimized the hardness of the weld and heat -affected zone to approximately the same as the base metal hardness (288 and 286 HV, respectively).