Comparative assessment on microstructure and mechanical properties of continuous and pulse-current GTA welds of AISI 304 and Monel 400

Abstract

This study investigates the weldability, microstructure and mechanical properties of dissimilar AISI 304 and Monel 400 welds using continuous and pulse-current GTA welding processes. Dissimilar joints of AISI 304 and Monel 400 are widely used in the marine and offshore environments, oil and gasification plants. These welding processes are carried out using three filler wires, namely E309L, ENiCu-7 and ENiCrFe-3. Microstructure examination is carried out on these dissimilar weldments. In addition, a comparative analysis on the microhardness, tensile test values on these welds using the above-said filler materials is also discussed. The weldments obtained from ENiCu-7 and ENiCrFe-3 filler wires offer high strength and ductility. These studies would be useful for the fabricators implementing these dissimilar weldments in the offshore applications.K e y w o r d s : dissimilar metal welding, mechanical properties, Monel 400, AISI 304 stainless steel

Study of metallurgical changes and mechanical properties of dissimilar weldments developed by interpulse current TIG welding technique

“…The alloying elements of filler wire can influence the weld bead configuration, formation of new phases and grain boundary structures which inturn has an influence on the mechanical behavior and the formation of hot cracks. 4,5 If the fusion zone has the lower resistance to corrosion in comparison to specimen materials, corrosion is seen to be concentrated on weld zone. This effect can be controlled by substitution of fillers having high Nickel or straight Chromium steels.…”