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

ISO 898 consists of the following parts, under the general title Mechanical properties of fasteners made of carbon steel and alloy steel:

• Part 1: Bolts, screws and studs with specified property classes — Coarse thread and fine pitch thread
• Part 2: Nuts with specified property classes — Coarse thread and fine pitch thread
• Part 5: Set screws and similar threaded fasteners with specified hardness classes — Coarse thread and fine pitch thread
• Part 7: Torsional test and minimum torques for bolts and screws with nominal diameters 1 mm to 10 mm)

This part of ISO 898 specifies mechanical and physical properties of nuts with coarse thread and fine pitch thread made of carbon steel and alloy steel when tested at an ambient temperature range of 10 °C to 35 °C.

Nuts conforming to the requirements of this part of ISO 898 are evaluated at that ambient temperature range. It is possible that they do not retain the specified mechanical and physical properties at elevated and/or lower temperatures.

Nuts conforming to the requirements of this part of ISO 898 have been used in applications ranging from –50 °C to +150 °C. It is the responsibility of users to consult an experienced fastener materials expert for temperatures outside the range of –50 °C to +150 °C and up to a maximum temperature of +300°C to determine appropriate choices for a given application.

This part of ISO 898 is applicable to nuts:

1. made of carbon steel or alloy steel;
2. with coarse thread M5 ≤ D ≤ M39, and fine pitch thread M8×1 ≤ D ≤ M39×3;
3. with triangular ISO metric thread according to ISO 68-1;
4. with diameter/pitch combinations according to ISO 261 and ISO 262;
5. with specified property classes, including proof load;
6. with different nut styles: thin nuts, regular nuts and high nuts;
7. with minimum height m ≥ 0,45D;
8. with a minimum outside diameter or width across flats s ≥ 1,45D;
9. able to mate with bolts, screws and studs with property classes according to ISO 898-1.

Designation of Nut Styles

• For standard hexagon nuts without flange and without prevailing torque feature, the following limits apply:
• style 2: high nut with minimum height m_min ≥ 0.89D;
• style 1: regular nut with minimum height 0.80D ≤ m_min < 0.89D;
• style 0: thin nut with minimum height 0.45D ≤ m_min < 0.80D.

Where:

D is the nominal thread diameter of the nut, in millimetres

m is the height of the nut, in millimetres