Selecting material and geometrical parameters for a boring cutter used in machining the nickel-based coatings

Design and development of a technology for machining the parts to be restored in the repair industry includes selection of their machining method and modes, cutting tools, etc., and is a complex task, which solution determines the restored product quality. Machining quality largely depends on the metal machinability, which is understood as the material ability to be cut. The paper considers features of a bush machining after restoration of the worn inner surface, this operation consists of black, clean and fine boring, as well as of honing. Operations of black and clean boring are the most difficult in machining the restored bushes. This happens because hardness of the resulting layers is in the range of HRC 48…55 after induction sintering with subsequent rolling, which complicates the cutters operation in bush boring. The PG-SR2 powder having the Ni-Cr-B-Si alloying system is used in the built-up welding of parts working under wear, corrosion, erosion and elevated temperature conditions. Rolling is eliminating significant waviness and surface roughness resulting from sintering. One of the important issues in machining the coatings applied by centrifugal induction sintering is selection of the cutting tool material for black and clean boring.