The Influence of Steel Microstructure in High-Speed High-Load Bearing Applications

In the bearings’ segment of machine tools, there is a strong demand for high-performance steel solutions. The bearings may operate under severe conditions of contact pressures of up to 3 GPa; rotating at speed factors in excess of 3 million ndm. Such conditions pose a high risk of bearing seizure failure. Improving lubrication conditions is complex as the bearing operating temperature must be well controlled. Adhesive wear was found to occur in hybrid steel-ceramic contacts. Another relevant failure mode is micropitting. It is demonstrated that macroscopic hardness is insufficient to predict the resistance of steel microstructures to surface-initiated fatigue. In this regard, strain-hardening and the breadth of the range of hardness values of microstructure phases play an important role.