Assessment of Mechanical and Metallurgical Features of Inconel 680 Weld Metal

The present study assessed the mechanical properties and metallurgical features of a new solid-solution Ni-based alloy called Inconel 680, which has been developed for high strength applications, including dissimilar welding for high strength steels. Steel plates were buttered with Inconel 680, to prevent any dilution with the steel. In sequence, the buttered steel plates were joined. Samples from the test plates were extracted for chemical composition analysis, metallography preparation, uniaxial tensile testing, and hardness and microhardness evaluations. Microstructural characterization was performed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results of the mechanical properties showed that the Inconel 680 alloy filler metal provides an excellent mechanical strength, including a high yield strength, with an average value superior to 600 MPa, and good ductility, reaching an elongation of at least 40%. In addition, this study provides valuable insight into the microstructure of the Inconel 680 alloy. The overall evaluation indicated that this filler metal is an excellent option for many dissimilar welding applications, such as API 5L X65 pipes internally cladded with Inconel 625.