Anti-seize compounds are designed to prevent threaded couplings from binding or sticking. They are applied to the threads of bolts and other mechanical fasteners, and are also known as anti-stick compounds and thread lubricants. In addition to preventing bolts and other threaded fasteners from sticking or freezing, anti-seize compounds are used to reduce friction and to prevent corrosion, galling, and galvanic pitting. 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. Copper, nickel, molybdenum disulfide, and graphite powders are common slip agents. Anti-seize compounds that contain metallic particulates and graphite powders are also used.
Selecting anti-seize compounds requires an analysis of product types, specifications, and materials. Product types are often listed as natural, synthetic, bio-based, copper dispersion, metal dispersion, and petroleum. Specifications include temperature resistance, particle size, density, flash point, dropping point, torque coefficient, and fail load. The American Society for Testing and Materials (ASTM) defines standards for flash point and dropping point, as well as for work penetration. In terms of materials, choices for anti-seize compounds include copper, nickel, zinc, aluminum, molybdenum disulfide, and graphite powders as slip agents. Solid lubricant powders may also be used in some anti-stick compounds and thread lubricants.
Anti-seize compounds differ in terms of features and applications. Some anti-stick compounds and thread lubricants provide rust prevention and corrosion inhibition features. Others, such as anti-seizing products that are compounded with calcium fluoride and graphite, are designed for acidic, caustic, high heat, or high-temperature conditions. Food-grade anti-seize compounds do not contain ingredients that are harmful to humans. In terms of applications, some anti-seizing compounds are used with machinery, gears, studs, bolts, pulleys, chains, and lifts. Others are used with tube fittings, pipe fittings, shackles, wire rope fittings, bolts, nuts, screws, boom guides, valve assemblies, pump mountings, chain drives, shafts, gaskets, press fit assemblies, taps and drills, metal fittings, and machinery. Automotive anti-seize compounds are also available.