scope:

NEN-EN-ISO 2320 specifies the functional properties for prevailing torque steel nuts when tested at an ambient temperature range of +10 °C to +35 °C. It includes a combined test method to determine the prevailing torque properties and the torque/clamp force properties at the same time. It applies to prevailing torque all metal type nuts and prevailing torque non-metallic insert type nuts: - with triangular ISO thread in accordance with ISO 68-1; - with diameter/pitch combination in accordance with ISO 261 and ISO 262; - with coarse pitch thread M5 to M39 or with fine pitch thread M8 × 1 to M39 × 3; - with thread tolerances in accordance with ISO 965-2; - with mechanical properties in accordance with ISO 898-2; Prevailing torque values specified in this standard are based on laboratory test conditions.