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. 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 high temperatures up to a maximum temperature of + 300 °C. This part of ISO 898 is applicable to the following flat captive and non-captive washers made of carbon steel, alloy steel, spring or alloy spring steel, with thickness from 0,2 mm to 12 mm: - plain washers (with or without knurls/chamfers); - square washers; - square hole washers; - shaped plates. It does not specify requirements for such properties as: - corrosion resistance; - weldability.