SPECIAL MATERIALS FOR BEARING BASIC INFORMATION AND TUTORIALS


The standard materials for ball and roller bearings are usually ANSI 52100 or equivalent “ball bearing steel” or case carburized steels. Industrial demands for special bearings to meet abnormal service requirements spur the continual search for new and improved bearing materials.

High temperatures, corrosive atmospheres, massive size, marginal lubrication, complex design, and space and weight limitations are typical abnormal requirements.

Conventional bearing steels are often inadequate when these problems are present. Sustained high operating temperatures reduce hardness, wear resistance, yield strength, and, therefore, bearing life. Conventional bearing steels also lack resistance to the oxidation that takes place at elevated temperatures.

Materials such as 440-C stainless or corrosion-resistant coated steels may be required for severely adverse environments. For extremely high speeds and high temperatures, special alloy steels and materials such as metallic carbides and ceramics are used.

The combination of bearing size, complexity of design, and space and weight limitations can be a governing factor in the selection of bearing material. For example, a large-diameter, thin-section bearing with integral gear teeth and bolt holes would require a material that could be selectively hardened.

Monel and beryllium copper are not as hardenable as bearing steels and are nonmagnetic and resist saltwater corrosion. These qualities make them excellent materials for marine applications.

Although low-carbon steels are the most popular, a variety of other materials is also used for bearing cages. Molded nylon, synthetic resin-impregnated fabrics, and bronze/brass are popular in the normal temperature ranges.

High-performance polymers, carbon steel, certain stainless steels, and iron-silicon bronze are used for higher temperatures.

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