ISO/NP 898-12

Mechanical properties of fasteners made of carbon steel and alloy steel — Part 12: Nuts with diameters above 39 mm and up to 100 mm and specified property classes

Scope

This document specifies the mechanical and physical properties and related test methods and marking for nuts with nominal diameters above 39 mm and up to 100 mm, made of alloy steel.
This document applies to nuts:
— with ISO metric thread in accordance with ISO 68-1,
— with diameter/pitch combinations in accordance with ISO 261 and ISO 262,
— with coarse pitch thread M42 to M68, and fine pitch thread M42x3 to M100x6,
— with specified property classes 8, 10 and 12 (including proof load),
— with thread tolerances in accordance with ISO 965-1, -2 or -5,
— of two different nut styles: regular nuts (style 1) and high nuts (style 2), see 5.1,
— with a minimum outside diameter or width across flats smin ≥ 1,41D,
and
— able to mate with bolts, screws and studs with property classes in accordance with ISO 898-11 (see ISO 16224).
WARNING Nuts conforming to the requirements of this document are tested at the ambient temperature range of 10 °C to 35 °C and are used in applications ranging from –50 °C to +150 °C, or up to +300 °C for specific applications. It is possible that they do not retain the specified mechanical and physical properties at lower and/or elevated temperatures. Therefore, it is the responsibility of the user to determine the appropriate choices based on the service environment conditions of the assembly.
For hot dip galvanized nuts, additional requirements are specified in ISO 10684.
This document does not specify requirements for functional properties such as:
— prevailing torque properties (see ISO 2320 for test method),
— torque/clamp force properties (see ISO 16047 for test method),
— corrosion resistance (see e.g. ISO 4042, ISO 10683 or ISO 10684),
— fatigue resistance, and
— weldability.