CPM Rex 20 is a cobalt-free super high speed steel made by the CPM (Crucible Particle Metallurgy) Process. It has heat treat response and red hardness comparable to that of M42 but offers better wear reisistance and greater toughness. CPM Rex 20 was originally designed to replace M42 in any application where cobalt is undesirable. Due to its unique combination of properties, CPM Rex 20 is used in non-cutting applications such as bearings and in plasticizing components such as screw segments, barrels and non-return valves.

The CPM process results in a homogeneous microstructure with a finer, more uniform carbide distribution imparting superior dimensional stability, grindability and toughness when compared to steels produced by conventional processes. The CPM process also allows the design of more highly alloyed grades which cannot be produced by conventional steelmaking.