Fatigue life of super duplex stainless steel sheets (UNS S32750) as influenced by micro plasma arc welding parameters: an investigation using the surface response method

Duplex steels play a vital role in manufacturing pipeline and ducts where they are exposed to severe corrosion environment. The inquiry into the optimal conditions for Micro Plasma Arc Welding (MPAW) has not yielded any definitive results, despite its intrinsic application for joining thin sheets in manufacturing industries, particularly in aerospace and automobile parts. (SDSS) Super duplex stainless steel UNS S32750 of 0.33 mm thin Sheet is butt welded utilizing MPAW in this work. The fatigue qualities must be studied due to frequent loading in service. Peak current, base current, pulse rate and pulse width are significant welding input parameters and fatigue life is the output. High cycle fatigue testing is done in tension-tension mode in this work. Keeping stress ratio at 0.1, loading is applied sinusoidally between 0.6 kN and 6 kN. Response Surface Method (RSM) amid Central Composite Design (CCD) is used to conduct 31 different experimental permutations, while keeping in mind four variables and five weld input parameter levels. Weld input parameters are varied, and the resulting charts show how the output responses change. Minitab software is used to create linear function-based mathematical models. At a confidence level of 95%, Analysis of Variance (ANOVA) is conducted. Surface Response Optimizer is used to calculate optimal fatigue life.