Anti-seize Compounds Information
Anti-seize compounds, also known as anti-stick compounds or thread lubricants, prevent threaded couplings from binding or sticking. They are applied to the threads of bolts and other mechanical fasteners. In addition to preventing bolts and other threaded fasteners from sticking or freezing, anti-seize compounds inhibit corrosion, provide sealing properties to improve gasket performances, and prevent galling and galvanic pitting. They may also include extreme pressure additives.
Most anti-sticking compounds consist of a solid lubricant dispersed in a grease or binder. The anti-seizing material provides an insulating barrier or layer between metal components and allows for the easy dismantling of fasteners and parts. Material composition largely dictates thermal performance. Aluminum, copper, nickel, molybdenum disulfide, and graphite powders are common slip agents. Anti-seize compounds that contain metallic particulates and graphite powders are also used.
Aluminum and copper compounds exhibit an extended temperature range and are rated at temperatures up to 1800° F.
Graphite-based compounds may be used for high voltage applications where an electrically conductive compound is required and may be rated at temperatures over 2000° F. Graphite may promote corrosion of aluminum, magnesium, and some ferrous alloys and is best suited for use with austenitic stainless steels, nickel, titanium, cobalt and other corrosion resistant alloys.
Molybdenum disulfide (MoS2) and nickel compounds are non-reactive and are used in applications where they may be subject to incidental contact with reactive chemicals such as acetylene or ammonia. They also excel in high temperature applications and are rated up to 2,600 °F.
Specifications include maximum operating temperature and flash point.
The maximum operating temperature is the maximum temperature that the material can be exposed to without thermal degradation.
Flash point is the lowest temperature that a liquid can give off sufficient vapors to form an ignitable mixture in air near the surface of the liquid. The lower the flash point, the easier it is to ignite the material.
Anti-seize compounds may be designated for use or meet rating for use in specialized applications including the following:
Aerospace – Aerospace compounds are suitable for aerospace applications and may include military specifications (MIL-SPEC), or military standards (MIL-STD).
Automotive – Automotive compounds are selected based on material and temperature compatibility and are used for a variety of threaded fasteners including brake calipers, spark plugs, and engine components.
Food grade – Food grade compounds include those have received Food and Drug Administration (FDA) approval, National Sanitary Foundation (NSF) approval, or are otherwise designed and suitable for use in processing equipment where contact with food, beverages or pharmaceuticals may occur.
Marine – Marine compounds are suitable for use on ships, dockyards or boats and resist oxidation.
Military – Military grade compounds are those that carry MIL-STD or MIL-SPEC ratings and are suitable for use in military applications.
MIL-PRF-907FV – Military specification for high temperature anti-seize compounds.
SAE AMS2518 - This specification covers an anti-seize compound in the form of a grease.