Abstract: Deposition of a first relatively hard material on a second material that is relatively soft using a rotating rod, bar, tube or other body without translation of the rotating body relative to a workpiece of the second material is achieved by positively cooling the interface between the body and the workpiece such that a shear layer at which heat is being generated moves away from the surface in the direction of the rotating body. On removal of the rotating body from contact with the workpiece, the workpiece is found to be surfaced with material from the rotating body. In a second stage the already deposited material from the rotating body may be cooled by a surrounding body of liquid to enable further material from the rotating body to be deposited on the workpiece. The workpiece may be of plain carbon steel and the rotating body may be of high speed steel or a nickel-based alloy.

Abstract: A hard facing of preferably a high speed tool steel or a Stellite along the edge of a substrate is produced by mechanical deposition by means of rotary friction surfacing. The combination of high temperatures below the melting points of coating material and substrate and high rates of strain gives rise to a very fine coating microstructure resulting in an edge or valve facing or seat of unexpectedly good mechanical properties and service life.