Best Grease for High Temperature Bearings

High temperature bearings are important in industries like automotive, steel production, and energy. They can handle extreme heat and still work well.

Extreme heat can damage bearings in several ways. It causes oxidation, where metal reacts with oxygen, forming rust that increases friction and wear. Heat also breaks down lubricants, making them less effective and causing more friction.

This can result in accelerated wear or even cause the bearing to seize. High temperatures can also weaken the bearing material, causing it to crack or fail. These problems shorten the bearing's lifespan and reduce its performance, making high temperature bearings necessary in hot environments.

The purpose of this blog is to help readers understand the criteria for selecting the best grease. It focuses on high temperature bearings and how to choose the right grease for optimal performance. This ensures the longevity and efficiency of equipment operating in high-heat environments.

Key Characteristics of High Temperature Bearings

High temperature bearings are made to work in temperatures above 250°F (120°C). Some special bearings can handle even higher temperatures, over 500°F (260°C). They are designed to remain reliable and efficient in extreme heat. This helps equipment last longer and reduces the need for frequent maintenance.

High temperature bearings are used in several heat-intensive applications, including:

• Industrial Ovens: Keep machinery running smoothly at high temperatures during processes like baking or curing.
• Kilns: Withstand extreme heat in industries like ceramics and metal production to maintain performance.
• Molten Salt Pumps: Ensure reliable operation in energy production systems that handle molten salt at high temperatures.
• Steam Turbines: Endure the heat from steam to maintain efficient operation in power generation.
• Automotive Conveyor Systems: They support the movement of parts through heat-sensitive processes. These processes include painting or curing in automotive manufacturing.

High temperature bearings face several challenges:

• Thermal Expansion: When heated, materials expand. This can cause parts of the bearing to rub against each other, increasing friction or causing the bearing to seize.
• Moisture Exposure: Changes in temperature can cause moisture to form, leading to rust and damage. This can break down the lubricant and reduce the bearing's lifespan.
• Contamination Risks: Dust or debris in the environment can enter the bearing. This can cause wear and disrupt its operation.

Factors to Consider When Choosing High-Temperature Grease

Evaluate the Operating Temperature Range

Selecting the correct grease for the application’s temperature range is crucial to ensure bearings operate effectively. If the grease is unable to withstand the heat, it will degrade and fail to provide proper lubrication.

This can cause increased friction, wear, and even bearing failure. Selecting the appropriate grease ensures the bearings operate efficiently and minimizes maintenance requirements. It also extends the equipment's life in high-heat conditions.

For high temperature bearings, it’s important to use the right grease. Lithium complex grease works well up to 250°C, while PFPE-based greases can handle temperatures up to 300°C or more. Using the right grease helps reduce wear, friction, and helps the bearings last longer in high-heat environments.

Assess the Base Oil Type

Compare mineral-based vs. synthetic oils:

• Mineral oils: These are more cost-effective and work well for moderate temperatures. They are commonly used in applications where the heat is not extreme and the performance requirements are lower.
• Synthetic oils (e.g., PAOs, PFPEs): These oils provide superior thermal stability and oxidative resistance. This makes them ideal for high-temperature environments. They last longer, resist breakdown in extreme heat, and provide better protection for bearings and machinery under harsh conditions.

Review Thickener Technology

List common thickeners:

• Lithium Complex: Offers moderate stability, commonly used in various applications.
• Calcium Sulfonate Complex: Provides high thermal stability and excellent rust resistance, ideal for high-heat environments.
• Polyurea: Known for good oxidative resistance, making it suitable for long-term performance in high temperatures.
• Carbon Black or Clay: These thickeners are used for extreme temperatures. They provide additional strength and durability under high heat conditions.

Consider Additive Packages

Oxidation inhibitors, anti-corrosion agents, and extreme pressure (EP) additives are important for keeping high temperature bearings working well:

• Oxidation Inhibitors: These additives prevent the grease from breaking down when it reacts with oxygen. This ensures the grease remains effective for an extended period, particularly in high-temperature conditions.
• Anti-Corrosion Agents: They protect the bearing surfaces from rust and corrosion. This helps maintain performance and extend lifespan, especially in humid or high-temperature environments.
• Extreme Pressure (EP) Additives: These additives create a protective layer on the bearings. This helps protect them under heavy loads and high pressure. This reduces friction and wear, helping the bearings last longer in tough conditions.

Compatibility with Application Conditions

When choosing grease for high temperature bearings, it's important to consider the following:

• Operating Cycles (Continuous vs. Intermittent): Grease in machines that run continuously needs to be more durable. This is because it is always under stress and heat. In machines that operate intermittently, the grease has periods to cool down, allowing it to better withstand heat.
• Moisture Exposure: In environments with moisture, grease must contain anti-corrosion agents. These agents help prevent rust and protect the bearings.
• Contamination Risks: In dusty or dirty environments, grease should resist contamination. Extreme Pressure (EP) additives help form a protective layer on the bearings. Good seals also prevent dirt and chemicals from entering the bearings.

Different types of grease should never be combined. They are made from different oils and thickeners, and mixing them can cause the grease to stop working properly. This can lead to more friction, faster wear, and even bearing failure. Always use the same type of grease or check if the new grease is safe to use with the old one.

Types of Grease for High Temperature Bearings

Lithium Complex Grease

Lithium Complex Grease is commonly used in many industries because it works well and is cost-effective. It can handle temperatures up to 250°C, making it good for moderate to high heat applications. This grease is often used in cars, machines, and bearings that need reliable lubrication in hot conditions.

Polyurea Grease

Polyurea Grease is known for its excellent oxidative stability, meaning it resists breaking down even at high temperatures. This makes it ideal for continuous high-temperature operations, where it can provide long-lasting lubrication without degrading. It is commonly used in industries that require consistent performance in hot conditions. This includes applications in motors, fans, and high-speed machinery.

Calcium Sulfonate Complex Grease

Calcium sulfonate complex grease is ideal for high temperatures because of its high dropping point. This property ensures it doesn't melt easily, providing reliable lubrication in extreme conditions. It also protects against corrosion, stopping rust and damage to metal surfaces. Plus, it has extreme pressure (EP) properties, which help reduce wear and friction under heavy loads.

This grease is perfect for moist environments, like steam turbines or outdoor equipment, where it’s exposed to water or harsh weather. Its ability to resist rust and handle pressure makes it ideal for these conditions.

PFPE-Based Grease

PFPE-based grease is a high-quality grease that resists oxidation and chemical damage. This makes it perfect for use in tough conditions. It lasts longer in extreme heat and harsh environments.

It is commonly used in aerospace and chemical industries, where it can handle very high temperatures. Moreover, it is resistant to strong chemicals, ensuring that equipment operates efficiently and reliably.

Tips for Using High-Temperature Grease Effectively

Measure Actual Operating Temperatures

To measure the actual temperature, you can use sensors. Contact sensors touch the equipment to provide accurate readings. Non-contact sensors, such as infrared thermometers, can measure temperature from a distance. This helps make sure the bearings and grease stay within their safe temperature range, avoiding damage.

Avoid Over-Lubrication

Over-lubrication can cause problems by trapping excess grease inside the bearing. This can lead to thermal buildup, as the extra grease can overheat and break down, leading to higher temperatures.

It can also attract contamination, such as dirt or dust, which gets trapped in the thick grease, leading to wear and damage. Using the correct amount of grease is crucial to ensure the bearings operate smoothly and avoid potential problems.

Establish Proper Relubrication Intervals

To set the right relubrication intervals, balance how often you add grease with how long it lasts. Too much grease can waste money and increase maintenance, while too little can cause damage. By finding the right timing, you can lower costs, reduce downtime, and keep bearings working well.

Test Compatibility Before Switching Greases

Always test compatibility before switching greases. Mixing different types of grease can cause them to break down or fail to perform correctly. This may lead to poor performance or even damage to the equipment. To prevent any issues, it's essential to verify that the new grease is compatible with the old one before use.

Real-World Examples

Steel Mill Bearings

Steel mill bearings need grease that can handle heavy loads and resist water. Calcium sulfonate grease is a great choice because it protects against rust and works well in hot, moist conditions. This helps the bearings last longer and work reliably.

Automotive Conveyor Systems

Automotive conveyor systems require high-temperature grease that can handle the heat from the machines while maintaining its performance. The grease must have oxidative stability to prevent it from breaking down. This is crucial to withstand high temperatures and exposure to oxygen. This helps ensure smooth operation, reduces maintenance, and extends the life of the system.

Industrial Ovens

In industrial ovens, you need non-melting grease because the heat is high. Regular grease can melt and stop working, which can damage equipment. PFPE-based and clay-thickened greases are perfect for this because they can handle high temperatures without melting. They keep the bearings working smoothly and last longer in hot conditions.

Benefits of Using the Right High-Temperature Grease

Reduce Maintenance Costs

High-quality grease extends the lifespan of bearings, reducing the need for frequent replacements. It protects against heat, wear, and rust, which means less maintenance and fewer repairs. This reduces downtime and stops early bearing failure, helping your equipment last longer.

Improve Equipment Longevity

Optimal lubrication is key to minimizing wear and tear under extreme conditions. The right grease reduces friction, keeping parts smooth and preventing damage from heat, pressure, or contaminants.

It forms a protective layer on the bearing surfaces, enhancing their durability. This helps them last longer, even in harsh environments such as high temperatures or heavy loads. By maintaining proper lubrication, you can keep equipment running smoothly and avoid costly repairs.

Enhance Operational Efficiency

Proper lubrication plays a critical role in reducing downtime and keeping equipment running smoothly. Ensuring that bearings and machinery are well-lubricated minimizes friction and reduces wear.

This helps lower the risk of failure. This leads to fewer breakdowns, less maintenance, and less need for repairs. As a result, machines run more efficiently, which helps maintain productivity and avoid costly downtime.

Top Grease Recommendations for High Temperature Bearings

MOLYKOTE® 41 Extreme High Temperature Bearing Grease

MOLYKOTE® 41 Extreme High Temperature Bearing Grease is made with carbon black thickener. This helps it remain stable and effective in hot conditions. It can withstand temperatures up to 290°C, making it ideal for machines operating in high-heat environments. This ensures reliable lubrication in demanding conditions.

Mobil SHC™ PF 462

Mobil SHC™ PF 462 is a PFPE-based grease known for its exceptional thermal and oxidative stability. It can handle temperatures up to 500°F (268°C), making it ideal for extreme heat conditions. This grease ensures reliable performance in high temperature applications by providing long-lasting lubrication. It also protects equipment from wear and breakdown.

Shell Gadus S5 T460

Shell Gadus S5 T460 is a calcium sulfonate complex grease that works well in wet and corrosive environments. It protects against rust and water, making it ideal for environments like marine or steel industries. In these areas, equipment is often exposed to moisture and harsh conditions. This grease ensures the smooth operation of machines and extends their lifespan.

Klüber STABURAGS NBU 30

Klüber STABURAGS NBU 30 is a high-performance grease that is excellent for high-speed applications. It offers great thermal stability, meaning it can handle high temperatures without losing its effectiveness. This makes it ideal for machinery that operates at high speeds. It requires reliable lubrication to perform smoothly and last longer.

Conclusion

High-temperature grease is important for keeping bearings reliable in tough conditions. It helps reduce friction and wear at high temperatures, preventing overheating and rust. This makes bearings last longer and work smoothly, lowering the chances of failure and reducing maintenance costs.

When choosing high-temperature grease, make sure to consider the temperature range, base oil, thickener, and additives. The temperature range ensures it can handle the heat, while the base oil helps it lubricate properly. The thickener keeps it stable, and the additives improve things like rust protection. Picking the right grease based on these factors helps bearings work well and last longer.

For the best results, talk to experts or manufacturers for advice on the right grease. They can help you pick the best grease based on your equipment, conditions, and temperature needs. This will help your bearings work better and last longer.