Effect of nanoparticle on mechanical properties of activated tungsten gas welding of austenite stainless steel 316L and optimization of process parameters

Abstract

Abstract Austenite stainless steel 316L was developed to improve corrosion resistance and is widely used in automobile components, thermal power plants, and pressure vessels due to their superior toughness and intergranular corrosion resistance. The austenite stainless steel 316L has a low carbon content of 0.03%, which helps in minimizing harmful carbide precipitation during welding. The joint strength of welded joints is poor unless proper care is taken. As a result, an attempt was made to use an activated Tungsten Inert Gas (A-TIG) welding procedure to improve the joint strength of butt welded joints of austenitic stainless steel 316L. The process parameters such as current, the volume of flow, and filler diameter were chosen in the study and generated an L 9 design matrix using MINI Tab software. The welded joints were prepared as per the design matrix using the activated flux of aluminum oxide nano powder as per the combination of process parameters. The mechanical tests such as tensile strength, hardness, and impact strength were evaluated and microstructural evaluation of welded joints was also assessed. The input parameters were optimized for better tensile strength of joints using Taguchi S/N analysis. It is found from the optimization that the highest ultimate tensile strength of 690.40 MPa was obtained at a current of 90 A, shielding gas flow of 13 l min–1, and filler material diameter of 2.5 mm. The model was also validated by conducting experiments.