Investigation on metallurgical and mechanical behaviours of inconel 625 overlaids on aisi 347 stainless steel

Abstract

Hardfacing is the most commonly adopted method to enhance the wear properties of new/used component surfaces of the machineries widely used in agricultural tools and equipment, components for mining operations, soil preparation machineries and power plants etc. Austenitic stainless steels are generally used in high temperature environments due to their attractive features like excellent resistance to intergranular corrosion, mechanical strength, weldability, cost and economy factors etc. AISI 347 is frequently employed for aircraft collector rings, exhaust manifolds and high temperature chemical process equipment. Heat exchanger components of boilers in thermal power stations, gas turbines, and food processing industries are unprotected by severe corrosive and erosive environments that lead to premature failure of the Fe-based alloy components.Inconel 625 is a widely employed material for hardfacing to protect components of aircrafts, oil refinery and power generation, possessing better corrosion resistance behaviour at high temperature applications. These characteristics are related with the hardfacing material composition and microstructure of overlaid welds which is influenced by the process parameters and the substrate composition of the component to be protected.In this research, single bead overlays of Inconel 625 were deposited on the surface of AISI 347 pipe by GMAW process. Overlaid welds were deposited at three different heat inputs (0.48 kJ/mm, 0.53 kJ/mm and 0.59 kJ/mm) to synergic mode, while the voltage and wire feed rate are pre-programmed. newline