This International Standard specifies the mechanical properties of nuts with specified proof load values when tested at room temperature (see ISO 1). Prop-erties will vary at higher and lower temperature.
It applies to nuts
— with nominal thread diameters up to and includ-ing 39 mm;
— of triangular ISO thread and with diameters and pitches according to ISO 68 and ISO 262 (coarse thread);
— with diameter/pitch combinations according to ISO 261 (coarse thread);
— with thread tolerances 6H according to ISO 965-1 and ISO 965-2;
— with specific mechanical requirements;
— with widths across flats as specified in ISO 272 or equivalent;
— with nominal heights greater than or equal to 0,5D;
— made of carbon steel or low alloy steel.
It does not apply to nuts requiring special properties such as
— locking abilities (see ISO 2320);
— weldability;
— corrosion resistance (see ISO 3506);
— ability to withstand temperatures above 4- 300 °C or below - 50 °C.
NOTES
1 Nuts made from free-cutting steel should not be used above + 250 °C.
2 For special products such as nuts for high-strength structural bolting, and overtapped nuts for use with hot-dipped galvanized bolts, see the product standards for appropriate values
3 For assemblies with threads having tolerances wider than 6H/6g, there is an increased risk of stripping; see also table 1.
4 In the case of thread tolerances other or larger than 6H, a decrease of the stripping strength should be con-sidered (see table 1).
Table 1 — Reduction in thread strength
Test load, % Thread
Thread tolerances
greater less than or
than equal to 6H 7H 6G
M2.5 100 95.5
M2.5 M7 100 95.5 97
M7 M16 100 96 97,5
M16 M39 100 98 98.5
DS/EN 20898-2:1994 history
2012DS/EN ISO 898-2:2012 Mechanical properties of fasteners made of carbon steel and alloy steel - Part 2: Nuts with specified property classes - Coarse thread and fine pitch thread
1994DS/EN 20898-2:1994 Mechanical properties of fasteners. Part 2: Nuts with specified proof load values. Coarse thread