TIG welding process parameters were analysed for joining duplex stainless-steel plates. Signal to noise (SN) ratio and Analysis of Variance (ANOVA) analyses were applied for investigating the selected welding parameters. The selected parameters were current (A), gas flow rate (L/min) and speed (mm/min). The purpose of this work is to produce weld joints with maximum impact of strength and hardness. L9 orthogonal array was selected according to the aforementioned factors with three levels. The impact strength of the joints was found using the Izord impact testing machine and hardness of all joints was measured using the Brinell Hardness machine. From the SN ratio analysis, it was observed that for the high impact strength, the required welding current was 150 A, gas flow rate was 14 L/min and the welding speed was 210 mm/min while for high hardness, the welding current was 190 A, gas flow rate was 12 L/min and the welding speed was 175 mm/min. ANOVA analysis indicated that the gas flow rate was the most significant one for both impact strength and hardness of the joints.

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