Pitting corrosion characteristics of gas tungsten arc welded austenitic steel

Original scientific paper

Abstract

This study utilized a hybrid optimization technique, specifically the Taguchi-based grey-fuzzy logic, to optimize gas tungsten arc welding parameters with regard to tensile strength and hardness of 316L austenitic stainless steel. The Taguchi L27 orthogonal design of experiments was employed to optimize four input parameters: welding current, speed, voltage, and gas flow rate, to assess the pitting corrosion properties of the steel. Potentiodynamic polarization tests using a potentiostat were conducted to evaluate the pitting corrosion resistance of the welded samples. Microstructural analyses, aided by scanning electron microscopy, were performed to assess the surface morphologies of the steel samples. Subsequently, a confirmatory experiment was carried out to validate the optimization technique used. The results obtained indicate that the optimal welding parameters are a current of 95 A, speed of 0.7 mm/s, voltage of 25 V, and gas flow rate of 20 L/min, showing that the optimized steel sample exhibited an improvement in the multi-response performance index in terms of mechanical properties from 0.0409 to 0.495. By utilizing the strengths of both methods and integrating this hybrid optimization technique, the study provides valuable insights into the relationship between welding parameters and corrosion resistance, ultimately contributing to the development of more durable and reliable stainless-steel components.