Cladding Inconel 625 on cast iron via bypass coupling micro-plasma arc welding

There is great interest to deposit a layer of Inconel 625 nickel-base super-alloy on the surface of metallic substrate to increase the corrosion resistance for the services in harsh environment. In this work, we use the bypass-coupled micro-plasma arc welding to form a layer of Inconel 625 on the plate of QT-400 nodular cast iron and study the effect of the bypass current on the topology of the Inconel 625 layer. There exists spatial distribution of dendrites in the cladding layer along the direction normal to the bonding interface between the cladding layer and the plate of QT-400 nodular cast iron. The fusion zone near the interface between the cladding layer and the plate of QT-400 nodular cast iron has the largest Vickers hardness of 630 HV.