What Is High Temperature Grease?
High temperature grease is a specialized lubricating grease formulated to maintain its structure, lubricity, and protective properties at elevated temperatures that would cause conventional greases to fail. When operating temperatures exceed the capabilities of standard lithium grease (typically above 130 degrees C), a dedicated high temp grease becomes essential to prevent equipment damage, premature wear, and costly downtime.
As a leading China grease manufacturer, HENGHUA Petrochemical produces a comprehensive range of heat resistant grease products designed for the most demanding industrial environments.
Understanding Dropping Point
The dropping point is the temperature at which grease passes from a semi-solid to a liquid state under standardized test conditions. It is a critical specification for evaluating high temperature grease performance:
- Standard Lithium Grease: Dropping point of approximately 190 degrees C, with a practical operating limit of around 120-130 degrees C.
- Lithium Complex Grease: Dropping point above 260 degrees C, suitable for continuous operation up to 160-180 degrees C.
- Polyurea Grease: Dropping point above 250 degrees C, excellent for electric motor bearings at elevated temperatures.
- Silicone Grease: Dropping point above 250 degrees C, with exceptional thermal stability for intermittent high-temperature exposure.
It is important to note that the dropping point is not the maximum usable temperature. The practical operating limit of any extreme temperature grease is typically 50 to 100 degrees C below its dropping point.
What Makes Grease High-Temperature Resistant?
Several factors determine the performance of high temperature grease under thermal stress:
- Thickener Type: Complex soap thickeners (lithium complex, calcium sulfonate complex) and non-soap thickeners (polyurea, clay, silicone) provide superior thermal stability compared to conventional soap thickeners.
- Base Oil Quality: Synthetic base oils (PAO, ester, silicone) resist oxidation and thermal breakdown far better than mineral oils. High temperature lubricant products often use synthetic or highly refined base oils.
- Antioxidant Additives: Advanced antioxidant packages slow the oxidation process that causes grease to harden and lose lubricating properties at high temperatures.
- Thickener Structure: A stable thickener structure prevents oil separation (bleeding) and maintains grease consistency under thermal cycling conditions.
Applications of High Temperature Grease
Industrial Ovens and Furnaces
Conveyor bearings, fan bearings, and door hinges in industrial ovens and furnaces require heat resistant grease that can withstand continuous temperatures of 200-300 degrees C. Silicone and clay-based greases are commonly used in these applications.
Automotive Wheel Bearings
Modern vehicles, especially those with disc brakes, generate significant heat at the wheel hub. High temperature grease ensures reliable bearing lubrication even during extended braking or high-speed driving. Lithium complex and polyurea greases are the preferred choices for automotive applications.
Steel Mills and Foundries
Rolling mill bearings, continuous casting equipment, and furnace door mechanisms operate in extreme heat environments. Extreme temperature grease with synthetic base oils and robust antioxidant packages is essential for these applications.
Electric Motors
Large industrial electric motors generate considerable heat during operation. Polyurea grease is the standard recommendation for electric motor bearings due to its excellent thermal stability and long service life at elevated temperatures.
Aerospace and Aviation
Aircraft wheel bearings, actuators, and engine accessories require high temperature lubricant products that meet stringent performance specifications under extreme thermal cycling conditions.
Types of High Temperature Grease
Lithium Complex Grease
Offering the best balance of high-temperature performance and mechanical stability, lithium complex grease is the most versatile option for temperatures up to 180 degrees C. It is widely used in automotive, industrial, and agricultural applications.
Polyurea Grease
Polyurea grease excels in electric motor bearings and sealed-for-life applications. It offers excellent oxidation resistance and long service intervals at temperatures up to 160-180 degrees C.
Silicone Grease
For intermittent high-temperature exposure up to 250 degrees C or more, silicone grease provides outstanding thermal stability. However, its load-carrying capacity is lower than soap-thickened greases.
How to Select the Right High Temperature Grease
When choosing a high temp grease, consider these key factors:
- Maximum and minimum operating temperatures
- Load and speed requirements
- Environmental exposure (water, dust, chemicals)
- Relubrication intervals
- Compatibility with existing grease and seal materials
HENGHUA High Temperature Grease Solutions
DONGYING HENGHUA PETROCHEMICAL CO.,LTD offers a complete range of high temperature grease products manufactured to international standards. As a trusted China grease manufacturer, we provide expert technical support to help you select the optimal product for your application.
Browse our full product catalog or contact our engineering team for customized high-temperature lubrication solutions.
About the Author: HENGHUA Petrochemical (DONGYING HENGHUA PETROCHEMICAL CO.,LTD) is a leading China grease manufacturer specializing in high temperature, lithium, calcium, and specialty greases for industrial applications worldwide.