This International Standard specifies the mechanical and performance properties for prevailing torque type
steel nuts when tested at an ambient temperature range of +10 °C to +35 °C. It includes a single test to
determine the prevailing torque properties (performance properties) and/or the torque/clamp force properties.
This International Standard applies to prevailing torque all metal type nuts and prevailing torque non-metallic
insert type nuts:
a) with triangular ISO thread according to ISO 68-1;
b) with diameter/pitch combination according to ISO 261 and ISO 262;
c) with coarse pitch thread M3 to M39 and mechanical properties according to ISO 898-2;
d) with fine pitch thread M8×1 to M39×3 and mechanical properties according to ISO 898-6;
e) within the temperature range of −50 °C to +150 °C for prevailing torque all metal type nuts;
BS EN ISO 2320:2008 Referenced Document
ISO 16047 Fasteners — Torque/clamp force testing AMENDMENT 1
ISO 273:1979 Fasteners; Clearance holes for bolts and screws
ISO 898-1 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; Technical Corrigendum 1*， 2013-04-01 Update
ISO 898-2 Fasteners — Mechanical properties of fasteners made of carbon steel and alloy steel — Part 2: Nuts with specified property classes*， 2022-09-30 Update
ISO 898-6 Mechanical properties of fasteners - Part 6: Nuts with specified proof load values - Fine pitch thread
ISO 965-2 ISO general purpose metric screw threads - Tolerances - Part 2: Limits of sizes for general purpose external and internal screw threads - Medium quality; Amendment 1*， 2021-06-30 Update
BS EN ISO 2320:2008 history
2016BS EN ISO 2320:2015 Fasteners. Prevailing torque steel nuts. Functional properties
2008BS EN ISO 2320:2008 Prevailing torque type steel nuts - Mechanical and performance properties
1998BS EN ISO 2320:1998 Prevailing torque type steel hexagon nuts - Mechanical and performance properties
1973BS 4929-1:1973 Specification for steel hexagon prevailing-torque type nuts. Metric series