TYPE Review

Bearing steel, as the core material of key transmission and support components, has its surface performance directly determining the reliability, stability, and service life of the bearing system. To address this, research has established four major surface modification technology systems: surface mechanical strengthening, surface heat treatment strengthening, surface coating strengthening, and hybrid strengthening. This review systematically summarizes the progress of these four systems, focusing on their strengthening mechanisms, microstructural evolution, and effects on the service performance of bearings. Surface mechanical strengthening improves the surface layer’s resistance to crack initiation and propagation through grain refinement induced by existing methodologies. Furthermore, surface heat treatment enhances durability by altering the microstructure, while surface coatings provide an additional layer of protection against wear and corrosion. The advancements in hybrid strengthening also show promising results by combining multiple technologies for superior performance. These developments not only extend the lifespan of bearing steels but also enhance their application in demanding environments.