Reclaiming worn cylindrical hard metal tools - by sintering hard metal outer ring onto undersize tool

摘要

A composite part is made of hard metal, where a powder mixt. of hard metal is moulded into a hollow cylinder (2) which is then located round a cylinder (1) also made of hard metal. The two parts (1, 2) are sintered, so that part (2) shrinks and is firmly bonded to the periphery of part (1). Sintering pref. occurs at high temp. in a gas, part (2) may be presintered, and >=1 sintering operation may be used. In an example, sintered tools are made from tungsten carbide and cobalt, and are reground after wear until the outside dia. is below the min. permitted; the tool is then scrap. The undersired (1) can be placed in an outer ring (2) of carbide and the assembly sintered so ring (2) shrinks onto (1). Costly materials are saved.