Material Selection for Bearing
Bearings are an essential component of many machines, measuring the accuracy and precision of their operation often relies on the quality of the bearings. For example, ball bearings are employed for devices such as fans, gearboxes, and pumps. Motors, automobiles, and agricultural equipment also use ball bearings. Selecting the best bearing for any machine relies not only on the type of bearing, but also the correct material selection.
The composition of bearing materials can vary greatly, depending on the type of bearing. Roller bearings typically employ brass, synthetic resins, carbon steel, alloy steel, white metal, or stainless steel construction. Ball bearings can be made of ceramics, steel, bronze, brass, or plastic. Ceramic and stainless steel ball bearings often have longer service lives and require less maintenance than other materials, however, they are also more expensive.
Often, the type of material necessary for a given bearing is determined by the environment it will be operating in. Generally, stainless steel bearings work best in hot, corrosive environments because of their ability to resist rust and wear. Carbon steel bearings can also be used in such applications, however, their lack of corrosion-resistance can be a problem. Brass bearings, on the other hand, are low cost and perform well in applications with moderate moisture.
In some cases, the condition of the environment is not an issue. For instance, in applications where noise tolerance is critical, plastic bearings may be employed since they produce very low noise levels. Plastic bearings, however, are not suitable for areas with high loads, even with lubrication as they can deform easily under large forces. Alloy steel or brass bearings are usually better in this type of environment.
The type of lubricant used with the bearin can also serve as an influencing factor. Typically, most bearing materials will work fine in conjunction with oil-based lubricants. For more extreme environments, however, other lubricants, such as grease and polytetrafluoroethylene (PTFE) mixtures, may be needed.
In addition to the material type, bearings can also be distinguished by their construction. For instance, some have seals to protect the internal components from dust and debris, while others are unsealed. Sealed bearings can sometimes affect shaft speed or bearing life, and certain bearing applications may dictate the need for sealed bearings.
The most important factor for any bearing selection is an understanding of the application. The environment and intended use of the bearing should be taken into consideration in order to select the best material for the job. Strict adherence to bearing specifications and maintenance guidelines will ensure a longer service life and improved performance.
