Industrial Greases Information
Industrial greases are thickened gels that consist of natural, synthetic, or semi-synthetic substances. They can inhibit oxidation, corrosion, or microbial growth; provide sealing or barrier functions; or dampen shock and vibration. Passivators or deactivators are applied to internal or machined surfaces. Industrial greases do not run off of surfaces and are used in a variety of lubrication, sealing, and exclusion applications. Some products are designed for aerospace, automotive, marine, or military applications. Industrial greases that are rated for food, beverage, and pharmaceutical applications are also available. Others are suitable for use with bearings, combustion engines, processing equipment, compressors, piston pumps, gears, and final drives.
There are several basic types of products.
- Dielectric greases are designed to exclude water and reduce friction, binding, and wear.
- Vacuum greases are suitable for vacuum sealing or diffusion pump applications.
- Heat transfer products carry thermal energy in process heating and machine cooling applications.
- Micro-dispersion greases contain tiny particles of boron nitride (BN) graphite, polytetrafluoroethylene (PTFE), or molybdenum disulfide in a mineral, petroleum or synthetic oil base.
- Lapping or polishing compounds contain abrasive powders.
- High water content fluids (HWCF) and high water base fluids (HWBF) are used in industrial greases where leakage is likely to cause ignition.
- Wax, paraffin and stearate compounds are well-suited for anti-corrosive and anti-static applications.
- Grease soaps are used to thicken industrial greases. Typically, these grease soaps contain a sodium or calcium base and lithium or aluminum complexes.
Specifications to consider when selecting industrial greases include:
- Thermal conductivity - Thermal conductivity is a measure of the ability to transfer heat.
- Dielectric strength - Dielectric strength is the maximum voltage field that a material can withstand before electrical breakdown occurs.
- Specific gravity - Specific gravity is density normalized to water or another standard.
- Kinematic viscosity - Kinematic viscosity is the time required for a fixed amount of grease to flow through a capillary tube under the force of gravity. Units of measure include stoke, centistoke (1/100 of stoke) and Saybolt universal seconds (SUS).
- Operating temperature - Operating temperature is a full-required range.
- Boiling point - Boiling point is the temperature at which industrial greases boil.
- Flash point - Flash point is the lowest temperature at which substances produce sufficient vapors to form an ignitable mixture in air near the surface.
- Fire point - Fire point is the lowest temperature at which industrial greases produce sufficient vapors to form a mixture in air that continuously supports combustion after ignition.
- Fire Resistance - Fire resistant greases have high flash point, fire point and auto-ignition (AIT) temperatures.
- Autogenous ignition - Autogenous ignition (AIT) is the temperature at which ignition occurs spontaneously.
- Additives - Greases with extra pressure (EP) additives form a film to prevent sticking or seizing under heavy loads. Similarly, products with release agents prevent other materials from sticking or adhering to underlying surfaces. Non-foaming characteristics are achieved through the use of additives that break out entrained air.
- Biodegradability - Biodegradable products are designed to break down into harmless chemicals when released into the environment.