1.1 This specification covers the chemical, mechanical, and dimensional requirements for hardened steel washers for use with fasteners having nominal thread diameters of ¼ through 4 in. These washers are intended for general-purpose mechanical and structural use with bolts, nuts, studs, and other internally and externally threaded fasteners. These washers are suitable for use with fasteners covered in Specifications A325, A354, A449, and A490.

1.2 The washers are designated by type denoting the material and by style denoting the shape.

1.2.1 The types of washers covered are:

1.2.1.1 Type 1 - Carbon steel.

1.2.1.2 Type 3 - Weathering steel. Atmospheric corrosion resistance and weathering characteristics are comparable to that of steels covered in Specifications A588/A588M and A709/A709M. The atmospheric corrosion resistance of these steels is substantially better than that of carbon steel with or without copper addition. See 5.1. When properly exposed to the atmosphere, these steels can be used bare (uncoated) for many applications.

1.2.1.3 This specification provides for furnishing Type 3 to chemical composition or a Corrosion Index (CRI) of 6 or higher at the suppliers option.

1.2.2 The styles of washers covered are:

1.2.2.1 Circular - Circular washers in nominal bolt sizes ¼ through 4 in. suitable for applications where sufficient space exists and angularity permits.

1.2.2.2 Beveled - Beveled washers are square or rectangular, in nominal sizes ¹/₂ through 1½ in., with a beveled 1 to 6 ratio surface for use with American standard beams and channels.

1.2.2.3 Clipped - Clipped washers are circular or beveled for use where space limitations necessitate that one side be clipped.

1.2.2.4 Extra Thick - Extra thick washers are circular washers in nominal sizes ¹/₂through 1½ in., with a nominal thickness of ⁵/₁₆ in. suitable for structural applications with oversized holes.

1.3 Terms used in this specification are defined in Terminology F1789 unless otherwise defined herein.

1.4 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.

Note 1 - A complete metric companion to Specification F436M has been developed-Specification F436M; therefore no metric equivalents are presented in this specification.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.