ASTM International Standard Specification for Carbon and Alloy Steel Nuts (Inch and Metric) ASTM A563/A563M-21

This specification covers chemical and mechanical requirements for eight property classes of hex and hex-flange carbon and alloy steel nuts for general structural and mechanical uses on bolts, studs, and other externally threaded parts. Materials shall be tested and the individual grades shall conform to specified values of material such as hardness and proof load, chemical, and mechanical requirements. Classes 8S3 and 10S3 nuts have atmospheric corrosion resistance and weathering characteristics comparable to those of the steels. The atmospheric corrosion resistance of these steels is substantially better than that of carbon steel with or without copper addition. When properly exposed to the atmosphere, these steels can be used bare (uncoated) for many applications.