Finite element simulation for tensile and impact test of activated TIG welding of AISI 321 austenitic stainless steel

Abstract

Tungsten inert gas (TIG) welding process have been widely accepted in industries using stainless steel, titanium alloys and other 21st century metals to achieve high-quality weldments. TIG welding is mostly used to join workpieces with a thickness of less than 6 mm. To overcome this limitation of TIG welding, activated TIG welding (A-TIG) was employed to achieve high penetration depth in a single pass using activated flux. This article presents a study of experimental and finite element (FE) analysis on the mechanical behaviour of AISI 321 plate samples (base metal and weld metal) by performing a uniaxial tensile and Charpy impact test. The uniaxial tensile test is carried out for the base metal (BM) and A-TIG weld metal (WM) with a loading rate of 1 mm/min at room temperature. In the current FE analysis, the temperature and strain-rate dependent Johnson-Cook (J-C) model was utilised. The results of stress–strain values and impact energy predicted by the FE analysis agree with experimental results. Also, the fracture behaviour of the experimental and FE simulations were identical to ductile mode of fracture. In the FE analysis, the neck and fracture locations of the BM and WM specimens were very similar to the experiment. It is evident that the JC model results of uniaxial tensile test have a prediction error of 0.51% and 0.48% for BM and WM respectively. Also, similar accuracy with a prediction error of 2.21% and 3.19% for BM and WM Charpy test specimen, respectively. Scanning electron microscope results show that the failure of the BM and WM is initiated by ductile nature of the fused material at the joint.