scope:

This part of ISO 898 specifies mechanical and physical properties of flat washers, designed to be used in bolted joints in combination with bolts, screws, studs and nuts with a specified property class in accordance with ISO 898-1 and ISO 898-2.

NOTE 1 These types of washers may also be used with other fasteners such as screws forming their own mating thread.

Washers that conform to the requirements of this part of ISO 898 are evaluated at an ambient temperature range of 10 °C to 35 °C. These washers are used in applications at low or elevated temperatures up to a maximum temperature of + 300 °C, however see Note 2.

NOTE 2 When determining appropriate choices for a given application, users are advised to consult an experienced fastener expert for severe environmental applications including temperatures outside the range of − 50 °C to + 150 °C.

This part of ISO 898 is applicable to the following flat captive and non‑captive washers made of carbon steel or alloy steel, with thickness from 0,2 mm to 12 mm:

- plain washers (with or without knurls, ribbed or chamfers);

- square washers;

- square hole washers;

- shaped plates.

It does not specify requirements for such properties as:

- corrosion resistance;

- weldability.

NOTE 3 When designing critical applications, users are advised to consult a fastener expert.