1.1 This specification covers the chemical, mechanical, and dimensional requirements for metric hardened steel washers for use with fasteners having nominal thread diameters M12 through M100. 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 A325M, A490M, A563Mand with fasteners of Specification F568M property classes 8.8 and higher.

1.2 The types of washers covered in this specification are:

1.2.1 Type 1—Washers made of carbon steel.

1.2.2 Type 3—Washers made of steel having atmospheric corrosion resistance and weathering characteristics comparable to that of steels covered in Specifications A242/A242M, 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.

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

1.3 The styles of washers covered in this specification are:

1.3.1 Circular Washers—Circular washers in nominal sizes 12 mm through 100 mm, are suitable for applications where sufficient space exists and angularity permits.

1.3.2 Beveled Washers—Beveled washers are square and rectangular, in nominal sizes 12 mm through 36 mm, with a beveled 1:6 surface for use with American Standard beams and channels.

1.3.3 Clipped Washers—Clipped washers are circular or beveled for use where space limitations necessitate that one side be clipped.

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

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

Note 1—This specification is the metric counterpart of Specification F436.

1.6 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.