ASTM F 1137/F1137M : 2025

1.1This specification covers the basic requirements for six grades of corrosion protection for fasteners. Grade A consists of a heavy zinc phosphate coating with no additional sealer (dry), Grade B consists of a heavy zinc phosphate coating with a dry organic sealer, Grade C consists of a heavy zinc phosphate coating with supplemental dry-to-touch oil type compound, Grade D consists of a heavy zinc phosphate coating with supplemental protective oil type compound, Grade E consists of a grain-refined microcrystalline zinc phosphate with supplemental oil type compound, and Grade F consists of a manganese phosphate coating with supplemental oil type compound.

1.2This specification is intended primarily for fasteners such as nuts, clips, washers, and other ferrous threaded and non-threaded fasteners that require corrosion protection and lubrication.

1.3These coatings may or may not have a decorative finish.

1.4The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

1.5This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.