Hardfacing of austenitic stainless steel with nickel-base NiCr alloy

Abstract

Fast breeder reactors components encounter adhesive/abrasive wear nature and erosion. Hardfacing by weld deposition improves resistance to high temperature wear, especially galling, of mating surfaces in sodium. Based on induced radioactivity rate and shielding considerations, nickel-base E NiCr-B hardfacing alloy was chosen to replace cobalt-base Stellite alloys. Studies on this hardface deposit on austenitic stainless steel substrate demonstrated that deposits after exposure at service temperatures up to 823 K would retain adequate hardness (> RC 40) at end design service-life of 40 years. Also, the plasma transferred arc welding process was chosen for hardfacing to ensure that width of dilution zone could be controlled by optimising deposition parameters. The selection of nickel-base hardfacing alloy and deposition process used for development of hardfacing technology for various components of the Indian prototype fast breeder reactor is discussed.