The effective operation or failure of sliding bearings is closely related to the selection of load, speed, lubricating oil, and bearing geometry parameters. However, the reasonable selection of sliding bearing materials will play a decisive role in the performance of sliding bearing capabilities. The damage of wear-resistant materials for sliding bearings can cause damage to related parts, so sliding bearing materials should have good wear resistance, corrosion resistance, fatigue resistance, and pollution resistance.
Integrated sliding bearing structure
Partial sliding bearing structure
Oblique split sliding bearing
Overview of sliding bearing materials
The materials for the bearing shells and bearing liners that match the journal in the manufacture of sliding bearings. The main items for evaluating sliding bearing materials are: compressive strength and fatigue strength Wear resistance Break in performance Prevent friction compatibility with the shaft neck adhesion Compensate for the initial poor fit of the sliding surface compliance Allow hard particles to be embedded to reduce the embeddedness of journal scratches Thermal conductivity Corrosion resistance Processing processability Price, etc. But so far, there is no bearing material that can fully meet the requirements of these projects, and many projects are contradictory to each other. For example, the softer the metal material, the better its compliance and embeddedness, but the lower its strength, so soft metal materials can only be used as bearing liners Materials with high hardness also have high strength, but poor compliance and embedment. Bearing shells made from this material require small alignment errors between the shaft and the bearing. The selection of sliding bearing materials should be based on factors such as load, speed, temperature, lubrication conditions, and lifespan. Common sliding bearing materials include Babbitt alloy, copper based and aluminum based alloys, wear-resistant cast iron, plastic rubber, wood, and carbon graphite.
Babbitt alloy is a low melting point alloy mainly composed of tin, antimony, and copper, also known as white alloy or bearing alloy. The matrix of the alloy is a solid solution soft tissue composed of copper and antimony dissolved in tin, in which hard particles composed of tin copper antimony compounds are distributed. Soft tissues have good friction compatibility, compliance, and embeddedness, while hard particles have a certain ability to support loads. Babbitt alloy has low strength and can only be used as a bearing liner for soft steel, cast iron, or bronze bearings. Later, bearing alloys mainly composed of lead, antimony, and copper emerged. The former is called tin based Babbitt alloy, while the latter is called lead based Babbitt alloy. Tin based Babbitt alloy has a relatively high price and is mainly used for important bearings and large bearings for high-speed heavy loads. The performance of lead based Babbitt alloy is not as good as tin based alloy, but it is inexpensive and widely used, suitable for bearings with medium speed, medium load, and relatively stable load. Adding trace elements such as chromium and beryllium to manufacture high-strength Babbitt alloys is a new development direction.
Copper based alloys used as sliding bearing materials mainly include brass with copper and antimony as the main components Bronze mainly composed of copper and tin And copper lead alloy. Copper based alloys have high strength, good thermal conductivity and wear resistance, and allow for higher working temperatures than Babbitt alloys. However, their compliance, embedment, and friction compatibility are not as good as Babbitt alloys, and they can be used as bearing bushings or bearing lining materials. Commonly used tin bronze containing tin and phosphorus, suitable for bearings subjected to medium speed heavy loads or impact loads Tin bronze containing tin, zinc, and lead, suitable for medium speed and medium load bearings Lead bronze has a high load-bearing capacity and fatigue strength, making it suitable for bearings with high speeds and impact loads Aluminum bronze has high strength and good corrosion resistance, making it suitable for low-speed heavy-duty bearings. Brass generally has lower performance than bronze, but it is inexpensive and mainly used for low-speed bearings. However, brass containing manganese and silicon has better performance than tin bronze.
Aluminum based alloys include aluminum antimony magnesium alloy, aluminum tin alloy, and aluminum silicon alloy. They have high compressive strength and fatigue resistance, good thermal conductivity and corrosion resistance, and are inexpensive. However, their friction compatibility, embeddedness, and compliance are poor, and they are widely used in internal combustion engine and compressor bearings. Wear resistant cast iron is inexpensive, but its anti friction performance is poor, and it can only be used for low-speed light load bearings.
Commonly used plastics include phenolic resin, nylon, polytetrafluoroethylene, and polyoxymethylene. Plastic bearings have good self-lubricating performance, low friction coefficient, good fatigue resistance, strong vibration absorption ability, good corrosion resistance and embeddedness, can be lubricated with water or emulsion, and can save non-ferrous metals. However, plastic has lower strength than metal, poorer heat resistance, lower thermal conductivity, and expands when exposed to oil or water. Therefore, a larger bearing clearance must be taken in the design. Adding certain fillers such as graphite, molybdenum disulfide, glass fiber, etc. to plastics can reduce the friction coefficient and improve wear resistance Adding copper powder can improve thermal conductivity and strength. Plastic bearings have been used in industries such as metallurgy, chemical, textile, food, instrumentation, and shipbuilding.
Rubber has excellent embeddedness and corrosion resistance. Rubber bearings can use water mixed with particle impurities as a lubricant, which is elastic, has vibration damping effect, runs smoothly, but has poor thermal conductivity. The working temperature should be below 70 ℃, otherwise it is prone to aging. Natural rubber is not oil resistant, and rubber bearings that require oil lubrication should use oil resistant rubber.
Wood has self-lubricating properties, low cost, and good corrosion resistance. Wooden bearings can be used in food machinery, grain processing machinery, etc. that require cleanliness and hygiene. Its working temperature shall not exceed 65 ℃. Hard woods such as ironwood, maple, and oak are suitable for making wooden bearings.
Carbon graphite has excellent self-lubricating and corrosion resistance, and can withstand high temperatures of 400 ℃, but its strength is poor and it needs to be pressed into a steel sleeve for use. This type of bearing can be used in environments that are difficult to lubricate, do not allow oil stains, have high temperatures, or are corrosive.
1. Characteristics of sliding bearing materials
1.1 Friction compatibility
The phenomenon of adhesion occurs when the journal comes into contact with the bearing material.
1.2 Embeddedness
The ability of sliding bearing materials to allow hard particles to be embedded and prevent scratching or wear. For metallic materials, low hardness and low elastic modulus result in good embeddedness, but not necessarily for non-metallic materials.
1.3. Run in properties
The ability to reduce journal or bearing machining errors, coaxiality errors, and surface roughness during the running in process to achieve uniform contact, thereby reducing wear force and wear degree.
1.4. Friction compliance
The material compensates for the initial poor performance of the sliding surface through the elastic plastic deformation of the surface layer.
1.5. Wear resistance
The ability of materials to resist wear and tear.
1.6. Fatigue resistance
The ability of materials to resist fatigue failure under cyclic loading. Materials with good break in and embedding properties usually have low fatigue resistance.
1.7. Corrosion resistance
The ability of materials to resist corrosion, and the oxidation of lubricating oil produces acidic substances. This acidic substance and very few additives in the oil can corrode the material.
1.8. Gas resistance
The ability of materials to resist cavitation. Due to the rupture of bubbles in the oil near the solid surface, local impact high pressure or local high temperature can cause material wear.
With the development of disciplines such as materials science, engineering mechanics, tribology, and design theory, the material and structural design of sliding bearings have also been further improved. Considering economic benefits, environmental protection, production and processing, by understanding the material characteristics of sliding bearings and selecting suitable sliding bearing materials, efficient, green and energy-saving sliding bearings have been produced.
2025 July 5th Week Marginal Product Recommendation:
MG-TEX Steel with PTFE Fiber Fabric Bearings:
This new material uses the PTFE fibre fabric overlay on steel backing, the fabric is with high load capacity and much longer operating life comparing with conventional 3-layer bushes.The metal matrix provides the bearing with excellent load-bearing performance and can transfer the heat generated during the operation of the bearing in time, while PTFE woven material is designed to be used in completely dry friction conditions. It has a lower friction coefficient and excellent wear resistance. Compared with traditional bearings, in addition to high load performance, it can completely eliminate oil and eliminate process maintenance, and it slides smoothly. There will be no "sticky" phenomenon.
https://www.marginalbearings.com/steel-with-ptfe-fiber-fabric-bearings/mg-tex-steel-with-ptfe-fiber-fabric-bearings1.html
