Schaeffler has developed a new steel for rolling bearings which, combined with a carbonitriding heat treatment process, offers both harder surfaces and a higher ductility than other steels. Compared to standard bearings, devices made from this material – called Mancrodur – can have 30% higher load ratings and operating lives that are up to six times longer.



The new steel is particularly suitable for tough applications, subject to contamination or poor lubrication. For years, materials engineers have been trying to produce bearing steels that are more resistant to friction or contamination. They have had to balance the need for hard, wear-resistant raceways, against the ability to tolerate particles during over-rolling.

Mancrodur is said to achieve both of these aims. Though tough, it can level out ridges in raceways caused by embedded foreign materials. This reduces fatigue and prevents the formation of cracks, extending operating lives. Mancrodur is also able to withstand temperature rises caused by friction in applications with poor lubrication.

Under normal lubrication conditions, carbonitrided Mancrodur increases basic load ratings by 30% compared to standard materials.

These claims have verified in test applications, including a hot strip steel mill, where four-row roller bearings made from the new material achieved twice the usual operating life.