Microstructure, Hardness and Corrosion Behavior of Gas Tungsten Arc Welding Clad Inconel 625 Super Alloy over A517 Carbon Steel Using ERNiCrMo3 Filler Metal

摘要

In this study, Inconel 625 coating was deposited on the surface of A517 quenched and tempered low-alloy A517 steel using gas tungsten arc welding (GTAW) in order to increase the service life of the A517 substrate. For this purpose, Inconel 625 coating was deposited on steel surface by applying ERNiCrMo3 filler at different welding currents of 80, 100 and 120 A. The results showed that the microstructure of Inconel 625 coating consisted of a fully austenitic phase which was solidified having dendritic morphology, while A517 was found to be tempered martensitic. The average hardness of Inconel 625 coatings deposited at different welding currents was more than 230 HV. Evaluation of corrosion behavior also illustrated a better corrosion resistance of Inconel 625 coating than A517 base metal. The corrosion rate of Inconel 625 coating in 80 A, 100 A and 120 A samples was 0.435, 0.143 and 0.165 mpy, respectively, which were negligible in comparison with that of A517 steel (24.2 mpy).