1、BSI Standards PublicationBS EN ISO 2320:2015Fasteners Prevailing torquesteel nuts FunctionalpropertiesBS EN ISO 2320:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN ISO 2320:2015.It supersedes BS EN ISO 2320:2008 which is withdrawn.The UK participation in i
2、ts preparation was entrusted to Technical Committee FME/9, Fasteners.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct applic
3、ation. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 86178 9 ICS 21.060.20 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Comm
4、ittee on 31 January 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 2320 December 2015 ICS 21.060.20 Supersedes EN ISO 2320:2008English Version Fasteners - Prevailing torque steel nuts - Functional properties (IS
5、O 2320:2015) Fixations - crous autofreins en acier - Caractristiques fonctionnelles (ISO 2320:2015) Mechanische Verbindungselemente - Muttern aus Stahl mit Klemmteil - Mechanische und funktionelle Eigenschaften (ISO 2320:2015) This European Standard was approved by CEN on 17 October 2015. CEN member
6、s are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application
7、 to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Managemen
8、t Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Li
9、thuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17,
10、B-1000 Brussels 2015 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 2320:2015 EBS EN ISO 2320:2015EN ISO 2320:2015 (E) 3 European foreword This document (EN ISO 2320:2015) has been prepared by Technical Committee ISO/TC 2 “Fas
11、teners“ in collaboration with Technical Committee CEN/TC 185 “Fasteners” the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by June 2016, and conflicting nationa
12、l standards shall be withdrawn at the latest by June 2016. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN
13、 ISO 2320:2008. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedo
14、nia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 2320:2015 has been approved by CEN a
15、s EN ISO 2320:2015 without any modification. BS EN ISO 2320:2015ISO 2320:2015(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols 25 Thread . 36 Lubrication . 37 Mechanical properties of prevailing torque nuts . 38 Functional requirements for prevailing torque proper
16、ties 39 Test method 119.1 General 119.2 Proof load test . 119.3 Prevailing torque test . 119.3.1 General. 119.3.2 Test apparatus .129.3.3 Test parts . 129.3.4 Test procedure 139.3.5 Test report 15Annex A (normative) Temperature influence on prevailing torques of nuts with non-metallic insert 16Annex
17、 B (informative) Principles for the evaluation of the total coefficient of friction, tot17Annex C (informative) Test clamp force and prevailing torques for prevailing torque nuts M3 and M4 in property classes 8 and 10 18Bibliography .20 ISO 2015 All rights reserved iiiContents PageBS EN ISO 2320:201
18、5ISO 2320:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subje
19、ct for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC
20、) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be no
21、ted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying
22、 any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of
23、 users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplem
24、entary informationThe committee responsible for this document is ISO/TC 2, Fasteners, Subcommittee SC 12, Fasteners with metric internal thread.This fifth edition cancels and replaces the fourth edition (ISO 2320:2008), which has been technically revised. The following changes have been made: proper
25、ty class 9 has been deleted; prevailing torques for nuts M3 and M4 have been moved to Annex C; in the test fixture, the thread protrusion through the prevailing torque feature has been changed to 3 to 5 pitches; the reference surface condition for the test bolt has been specified in accordance with
26、ISO 16047 (plain surface, uncoated and degreased, unless otherwise agreed); the determination of the prevailing-off torque has been changed from the upper value to the minimum value (new point 5 in Figure 2), which changes the acceptance conditions; other editorial revisions.iv ISO 2015 All rights r
27、eservedBS EN ISO 2320:2015INTERNATIONAL STANDARD ISO 2320:2015(E)Fasteners Prevailing torque steel nuts Functional properties1 ScopeThis 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 inclu
28、des 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 diamet
29、er/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 ar
30、e 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 th
31、e 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.2 Normative referencesThe following
32、 referenced documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 273, F
33、asteners Clearance holes for bolts and screwsISO 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 threadISO 898-2, Mechanical properties of fasteners made of carbon steel and al
34、loy steel Part 2: Nuts with specified property classes Coarse thread and fine pitch threadISO 965-2, ISO general purpose metric screw threads Tolerances Part 2: Limits of sizes for general purpose external and internal screw threads Medium qualityISO 16047:2005, Fasteners Torque/clamp force testing3
35、 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 16047 and the following apply. ISO 2015 All rights reserved 1BS EN ISO 2320:2015ISO 2320:2015(E)3.1prevailing torque nutnut which is not free-running on a mating thread by virtue of a self-contained preva
36、iling torque feature, and which provides resistance to rotation independent of clamping or compression forces3.2prevailing torque developed by the nuttorque necessary to rotate the nut on its mating externally threaded component and without clamp force3.3prevailing-on torquetorque to rotate the nut
37、on its mating externally threaded component with the torque measured while the nut is in motion and without clamp force3.4prevailing-off torquetorque to rotate after backing off the nut until the removal of the clamp force in the following 360 rotation of the nut3.5prevailing torque all metal type n
38、utnut which has a one piece or a multiple piece metal construction and derives its prevailing torque characteristics from a controlled distortion of the nut thread and/or body and/or from metallic insert(s)3.6prevailing torque non-metallic insert type nutnut which has a multiple piece construction a
39、nd derives its prevailing torque characteristics from insert(s) of non-metallic material retained in the nut3.7seating pointpoint in the tightening process where clamp force first appears4 SymbolsFor the purpose of this International Standard, the following symbols apply together with those defined
40、in ISO 16047.D nominal diameter, in millimetred4diameter of the hole of the fixture, in millimetreFPproof load, in newtonF65lower load limit for the evaluation of the coefficient of total friction at 65 % of FP, in newtonF75upper load limit for the evaluation of the coefficient of total friction at
41、75 % of FP, in newtonF80test clamp force (shut-down force for the tightening process) at 80 % of FP, in newtonP pitch of the thread, in millimetreTFvprevailing-on torque, in newton metreTFdprevailing-off torque, in newton metreT65lower torque limit for the evaluation of the coefficient of total fric
42、tion at F65, in newton metreT75upper torque limit for the evaluation of the coefficient of total friction at F75, in newton metre2 ISO 2015 All rights reservedBS EN ISO 2320:2015ISO 2320:2015(E)T80test torque corresponding to 80 % of the proof load, in newton metre (see Tables 1 to 7)totcoefficient
43、of total friction5 ThreadThreads for prevailing torque nuts shall be in accordance with ISO 965-2 except for the prevailing torque feature:a) for prevailing torque non-metallic insert type nuts, the GO gauge shall be suitable for free installation (by hand) until it is seated against the prevailing
44、torque feature;b) for prevailing torque all metal type nuts, the GO gauge shall be suitable for free installation (by hand) to one pitch at least.6 LubricationAt the option of the manufacturer, a lubricant may be applied to the manufacturing lot to fulfil the functional requirements.7 Mechanical pro
45、perties of prevailing torque nutsThe mechanical properties of prevailing torque nuts shall conform to ISO 898-2.With regard to proof load, the test method specified in 9.2 shall apply.8 Functional requirements for prevailing torque propertiesThe prevailing-on torque shall not exceed the value specif
46、ied for the applicable nut in Tables 1 to 7.The prevailing-off torque shall exceed the value specified for the applicable nut in Tables 1 to 7.For delivery inspection, the first installation/removal test applies, unless otherwise agreed.For initial type testing and in case of dispute, a 5thremoval t
47、est shall also be applied unless otherwise agreed.Prevailing torque performance decreases as a function of the number of reuses; the consumer shall take into consideration the consequences of the decreased performance before any reuse of the nut.By request of the customer, a temperature influence te
48、st for prevailing torque non-metallic insert type nuts as specified in Annex A may be carried out. ISO 2015 All rights reserved 3BS EN ISO 2320:2015ISO 2320:2015(E)Table 1 Test clamp force and prevailing torques for prevailing torque nuts of property class 04Thread D DPTest clamp force F80aNClamp fo
49、rce for evaluation of total friction coefficient totbPrevailing torque NmUpper limit F75cNLower limit F65dN1stinstallation TFv,maxe1stremoval TFd,min5thremoval TFd,minM5 4 320 4 050 3 510 1,6 0,29 0,2M6 6 112 5 730 4 966 3 0,45 0,3M7 8 800 8 250 7 150 4,5 0,65 0,45M8 11 120 10 425 9 0356 0,85 0,6M81 11 920 11 175 9 685M10 17 600 16 500 14 30010,5 1,5 1M101,25 18 640 17 475 15 145M101 19 600 18 375 15 925M12 25 600 24 000 20 80015,5 2,3 1,6M121,5 26 800 25 125 21 775M121,25 28 000 26 250 22 750M14 34
