Bearing rings and rolling elements are usually made of high-carbon chromium bearing steel. Most bearings use CCr15. For bearing rings with larger cross-sections and rolling elements with larger diameters, CCrl5SiMn with good hardenability is used. High-carbon chromium bearing steel is a whole hardened steel, and its surface and core can be hardened. It is the best material for rolling bearings.
Due to different applications, some bearings require materials with special properties, such as impact resistance, high temperature resistance, corrosion resistance, and so on.
Carburized bearing steel is usually used for the rings and rolling elements of bearings that are subjected to impact loads during work or for large and extra-large bearings. Carburized bearing steel is carburized within the appropriate depth range of the surface layer of chromium-molybdenum steel, chromium-nickel-molybdenum steel or chromium-manganese-molybdenum steel to make it have a dense structure and form a hardened layer. Better core impact toughness, due to the good performance of carburized bearing steel, its life calculation is the same as that of high-carbon chromium bearing steel.
The bearings that work at high temperatures are made of high-temperature bearing steel with good heat resistance. The bearings that are in contact with corrosive media during work are made of stainless bearing steel.
It is worth noting that the cleanliness of bearing steel, the higher the cleanliness, the less non-metallic inclusions, the lower the oxygen content, and the longer the bearing fatigue life. Vacuum degassing or vacuum remelting steel can meet this requirement. Bearings requiring high reliability should be made of electroslag remelted steel.