ČSN EN ISO 2320

This International Standard 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. NOTE 1 - Actual prevailing torques in practical application can vary. NOTE 2 - All metal type nuts conforming to the requirements of this International Standard are used in applications ranging from -50 °C to +150 °C. NOTE 3 - Non-metallic insert type nuts conforming to the requirements of this International Standard are used in applications ranging from -50 °C to +120 °C. WARNING - Temperatures outside the ambient temperature range can influence the functional properties (torque/clamp force and prevailing torque properties), see Annex A.