Characteristics And Applications Of Commonly Used Bearing Materials

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Bearing alloys, bronze, aluminum-based alloys, zinc-based alloys, etc. are all called metal materials. Among them, bearing alloy, also known as white alloy, is mainly an alloy of lead, tin, antimony or other metals. It can have low strength under heavy load, high speed and other conditions. The reason is because of its characteristics, including good wear resistance, high plasticity, good running-in performance, good thermal conductivity, good glue resistance and good oil adsorption. However, because it is more expensive, when used, it must be poured on the bearing bush of bronze, steel strip or cast iron to form a thin coating.

Bearing alloys, bronze, aluminum-based alloys, zinc-based alloys, etc. are all called metal materials. Among them, bearing alloy, also known as white alloy, is mainly an alloy of lead, tin, antimony or other metals. It can have low strength under heavy load, high speed and other conditions. The reason is because of its characteristics, including good wear resistance, high plasticity, good running-in performance, good thermal conductivity, good glue resistance and good oil adsorption. However, because it is more expensive, when used, it must be poured on the bearing bush of bronze, steel strip or cast iron to form a thin coating.

(1) Bearing alloy (commonly known as Babbitt or white alloy)

Bearing alloy is an alloy of tin, lead, antimony, and copper. It uses tin or lead as the matrix and contains hard crystal grains of antimony tin (Sb-Sn) and copper tin (Cu-Sn). The hard grains play an anti-wear role, while the soft matrix increases the plasticity of the material. The elastic modulus and elastic limit of the bearing alloy are very low. Among all bearing materials, it has the best embeddedness and friction compliance. It is easy to run in with the journal and is not easy to seize with the journal. However, the strength of the bearing alloy is very low, and the bearing bush cannot be made separately. It can only be attached to a bronze, steel or cast iron bearing bush as a bearing lining. Bearing alloys are suitable for heavy-duty, medium-to-high-speed applications, and are more expensive.

(2) Copper alloy

Copper alloy has high strength, good friction reduction and wear resistance. Bronze has better properties than brass and is the most commonly used material. There are several types of bronze: tin bronze, lead bronze and aluminum bronze. Among them, tin bronze has the best friction reducing properties and is widely used. However, tin bronze has higher hardness than bearing alloy, poor running-in and embedding properties, and is suitable for heavy-load and medium-speed applications. Lead bronze has strong anti-adhesion ability and is suitable for high-speed and heavy-load bearings. Aluminum bronze has high strength and hardness and poor anti-adhesion ability, so it is suitable for low-speed and heavy-load bearings.

(3) Aluminum-based alloy

Aluminum-based bearing alloys have very good corrosion resistance, high fatigue strength, and good friction properties. These qualities have allowed aluminum-based alloys to replace more expensive bearing alloys and bronze in some areas. Aluminum-based alloys can be made into single-metal parts (such as bushings, bearings, etc.) or bi-metal parts. Bi-metal bearings use aluminum-based alloys as bearing linings and steel as backings. ˆ

(4) Gray cast iron and wear-resistant cast iron

Ordinary gray iron or wear-resistant gray cast iron with alloy components such as nickel, chromium, titanium, or ductile iron can be used as bearing materials. After the flake or spherical graphite in this type of material is covered on the surface of the material, it can form a layer of graphite that has a lubricating effect, so it has certain friction reduction and wear resistance. In addition, graphite can absorb hydrocarbons and help improve boundary lubrication performance. Therefore, lubricating oil should be added when gray cast iron is used as bearing material. Because cast iron is brittle and has poor running-in properties, it is only suitable for applications with light loads, low speeds and no impact loads.