Metallurgical, mechanical and corrosion behavior of Interpulse and pulsed current TIG dissimilar welds of Monel 400 and AISI 316L

This research work explores the weldability, structural integrity, mechanical properties, and corrosion behavior of dissimilar welds of Monel 400 and AISI 316L developed by using Interpulse and pulse arc current modes in TIG welding process. ERNiCrMo-3 filler of 1.6 mm was used to fill the V-groove configuration of 5 mm thick plates in multiple passes. Metallurgical changes were observed in both Interpulse and pulsed current dissimilar weldments using optical and scanning electron microscope techniques. Mechanical properties of the joined structures were evaluated by performing tensile tests on UTM and hardness measurements on weld surfaces using Vickers hardness tester. The resistance against the corrosion especially at the weld area of both welded structures was measured using a cyclic sweep test. From the XRT and visual inspection analyses, the joined structures were free from defects and also seen the uniformity of the filler distribution toward the base metals. The grain structure with well-defined grain structures were identified in PC-TIG weldments whereas fine grains with clear distribution of filler alloying elements were seen in Interpulse-TIG weldments. Interpulse-TIG weldments exhibited with better mechanical and corrosion resistance properties than the PC-TIG weldments vowing to constricted arc mode during the welding process.