NF EN ISO 2320
Prevailing torque type steel nuts - Mechanical and performance properties
ISO 2320:2008 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.ISO 2320:2008 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; f) within the temperature range of -50 °C to +120 °C for prevailing torque non-metallic insert type nuts.ISO 2320:2008 does not apply: 1) to nuts of type e), outside the range -50 °C to +150 °C for prevailing torque all metal type nuts, when it is necessary to consult an experienced fastener materials expert to determine appropriate choices for a given application; 2) to nuts of type f), when use at or near the temperature limits can reduce the prevailing torque capability of prevailing torque non-metallic insert type nuts and can require the use of an adequate non-metallic material — it is necessary to consult an experienced fastener materials expert for temperatures outside the range -50 °C to +120 °C for prevailing torque non-metallic insert type nuts to determine appropriate choices for a given application.
ISO 2320:2008 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.
ISO 2320:2008 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; f) within the temperature range of -50 °C to +120 °C for prevailing torque non-metallic insert type nuts.
ISO 2320:2008 does not apply: 1) to nuts of type e), outside the range -50 °C to +150 °C for prevailing torque all metal type nuts, when it is necessary to consult an experienced fastener materials expert to determine appropriate choices for a given application; 2) to nuts of type f), when use at or near the temperature limits can reduce the prevailing torque capability of prevailing torque non-metallic insert type nuts and can require the use of an adequate non-metallic material — it is necessary to consult an experienced fastener materials expert for temperatures outside the range -50 °C to +120 °C for prevailing torque non-metallic insert type nuts to determine appropriate choices for a given application.
ISO 2320:2015 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.
- Avant-proposiv
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1Domaine d'application 1
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2Références normatives 1
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3Termes et définitions 2
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4Symboles 2
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5Filetage 3
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6Lubrification 3
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7Caractéristiques mécaniques des écrous autofreinés 3
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8Exigences de performances pour les caractéristiques d'autofreinage 4
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9Méthode d'essai 13
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9.1Généralités 13
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9.2Essai de charge d'épreuve 13
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9.3Essai d'autofreinage 13
- Annexe A (normative) Essai de résistance à la température des écrous autofreinés à anneau non métallique18
- Annexe B (informative) Éléments de base pour l'évaluation du coefficient de frottement total, mtot19
- Bibliographie20
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