April 12, 2012
Bearings are made of many different materials, and many of these materials function more effectively in certain applications than others. Take a minute to learn about the many different types of materials bearings can be made of:
1. Chrome Steel – SAE 52100
This is the most common material used for precision ball bearings, roller bearings, and tapered roller bearings. This still has a high level of carbon within it and contains about 1.5% chromium.
These bearings have a high resistance to cracking and a hard surface, which helps them to resist wear and tear from rolling.
2. Extra Clean 52100 Chrome Steel
This type of steel is used to create precision miniature bearings. It is processed with additional melting steps. The resulting bearing is extremely quiet. Most often, the hardening process is done in a controlled atmosphere furnace. The resulting product can operate at temperatures up to 120°C.
SAE 52100 is by far the best general purpose steel for making bearings. It hardens to a very high level and has a long life when actually in use. However, the low chromium level of 1.5% means these bearings are not very resistant to corrosion.
3. Martensitic Stainless Steel – AISI 440C
This type of bearing has higher carbon content. The lower carbon content results in a softer material, however, it does allow for these bearings to be magnetic.
These bearings are slightly nosier than others, but they are able to operate at high temperatures of up to 250°C.
4. Martensitic Stainless Steel – 440C – ACD34
This material has smaller carbides in order to minimize noise, while also offering the same corrosion resistance as 440C. This is one of the most widely used materials for bearings, and it can bear similar loads to that of chrome steel.
5. Austenitic Stainless Steel
Bearing components made from this type of stainless steel have a high resistance to corrosion and are non-magnetic because they are made with low amounts of carbon. However, this material cannot be hardened, so it only works with low loads and low speeds.
These bearings are typically a special order and also carry a higher cost.