Experimental investigation on mechanical properties of TIG welded dissimilar AISI 304 and AISI 316 stainless steel using 308 filler rod

Abstract

The experimental investigation deals with the mechanical properties and the microstructure of the dissimilar Tungsten Inert Gas (TIG) welded AISI 304 and AISI 316. The two plates of 3 mm thickness were used in this study. The austenitic grade stainless steel offers a very good resistance to corrosion and finds its application in many industries. Austenitic stainless steel is prevalently used in chemical plants, heat exchanger, gas turbines, automobile industry. Additionally, austenitic stainless steels are easily formable and fabricable. TIG is the most commonly used welding technique to weld the austenitic stainless steel. In this study, butt welded joints have been made by three different levels of current. The effect of the welding current on the TIG weld has been studied and various mechanical tests have been taken in order to check the mechanical properties of the weld. The filler metal that has been employed in this study is AISI 308L of 2.5 mm diameter because it yields better mechanical properties and higher amount of martensite. The welding current was selected as 30, 45, 60 amps respectively. The welding voltages were taken as 40 V, 60 V and 80 V respectively. Hardness and tensile tests were performed over each specimen. The microstructure of the weld region was viewed by using Optical microscopy. The Brinell hardness test has proved that the hardness value of the weld zone is the highest when compared to heat affected zone and base metal. The specimen 3 which was TIG welded with 60A current exhibited the highest Ultimate tensile strength of 528.36 MPa.