1、Mechanical properties of fasteners Part 7. Torsional test and minimum torques for bolts and screws with nominal diameters 1 mm to 10 mm The European Standard EN 20898-7 : 1995 has the status of a British Standard BS EN 20898-7 : 1995 IS0 898-7 : 1992 COPYRIGHT European Committee for StandardizationL
2、icensed by Information Handling ServicesCEN EN*20898-7 95 W 3404589 0097975 747 BS EN 20898-7 : 1995 Standards Board and comes into 15 July 1996 O BSI 1995 effect on Amd. No. Date The foliowing FBI references relate to the work on this standard: Committee reference GMEI9 Draft for comment 90/80108 D
3、C JSBN O 58024385 O Committees responsible for this British Standard Text affected The preparation of this British Standard was entrusted to Technical Committee GME/9, Bolts, nuts and accessories, upon which the following bodies were represented: BEAMA Ltd. British Constructional Steelwork Associati
4、on Ltd. British Industrial Fasteners Federation British Steel Industry British Steel Industry (Wire Section) Gauge and Tool Makers Association National Association of Fastener Stockholders Society of Motor Manufacturers and Traders Ltd. Washer Manufacturers, Association of Great Britain The followin
5、g bodies also participated in the preparation of the standard, through subcommittees and panels: British Stainless Steel Association British Turned-parts Manufacturers Association Galvanizers Association Institute of Metal Finishing Metal Finishing Association National Centre of Tribology COPYRIGHT
6、European Committee for StandardizationLicensed by Information Handling ServicesCEN EN*20898-7 95 = 3404589 0097976 683 9 BS EN 20898-7 : 1995 Contents Committees responsible National foreword page Inside front cover 11 Fore word 2 Specification 1 Scope 2 Normative reference 3 Torsional test 3 3 3 4
7、Minimum breaking torques 4 5 Evaluation of the torque test 4 Annexes A (informative) Explanatory note 6 ZA (normative) Normative references to international publications with their relevant European publications 6 Ibles 1 Strength ratio X 5 2 Minimum breaking torques 5 Figure 1 Example of a device f
8、or the torsional test 4 i COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesCEN EN*20878-7 95 = 3404.589 0097977 51T W BS EN 20898-7 : 1995 National foreword This British Standard has been prepared by Technical Committee GME/9 and is the English language versio
9、n of EN 20898-7 : 1995 Mechanical properties of fasteners Part 7: lrsional test and minimum torques for bolts and screws with nominal diameters 1 mm to 10 mm published by the European Committee for Standardization (CEN). It is identical with IS0 898-7 : 1992, published by the International Organizat
10、ion for Standardization (ISO). EN 20898-7 : 1995 was produced as a result of international discussions in which the United Kingdom took an active part. Cross-reference Publication referred to IS0 898-1 : 1988 Corresponding British Standard BS EN 20898 Mechanical properties of fasteners Part 1 : 1992
11、 Specification for bolts, screws and studs Compliance with a British Standard does not of itself confer immunity from legal obligations. ii COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesCEN ENr20878-7 95 m 3404587 0077778 456 m EUROPEAN STANDARD NORME EUROP
12、ENNE EUROPISCHE NORM EN 20898-7 January 1995 ICs 21.060.10 Descriptors: fasteners, breaking torque, bolts, specification, mechanical properties, testing, torsion testing English version Mechanical properties of fasteners - Part 7: Torsional test and minimum torques for bolts and screws with nominal
13、diameters 1 mm to 10 mm (IS0 898-7 : 1992) Caractristiques mcaniques des lments de fixation - Verbindungselementen - Partie 7: Essai de torsion et couples minimaux de rupture des vis de diamtre nominal de filetage de 1 mm 10 mm Mechanische Eigenschaften von Teil 7: Torsionsversuch und Mindest-Bruchd
14、rehmomente fr Schrauben mit Nenndurchmessern 1 mm bis 10 mm (IS0 898-7 1992) (IS0 898-7 1992) This European Standard was approved by CEN on 1995-01-04. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the statu
15、s of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A ve
16、rsion in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, G
17、reece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B- 1050 Brussels O 1996 Copyrigh
18、t reserved to CEN members Ref. No. EN 20898-7 : 1995 E COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesPage 2 EN 20898-7 : 1995 Foreword This European Standard has been taken over by the Rchnical Committee CEN/TC 185, Threaded and non-threaded mechanical fast
19、eners and accessories, from the work of ISO/Tc 2, Fasteners, of the International Organization for Standardization (ISO). This European Standard shal be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 1995, and conflicting
20、national standards shall be withdrawn at the latest by July 1995. According to the CENKENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, No
21、rway, Portugal, Spain Sweden, Switzerland, United Kingdom. NOTE. Normative references to international publications are listed in annex ZA (normative). COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesCEN EN*Z0878-7 75 3404587 0077980 004 Page 3 EN 20898-7 : 1
22、995 Mechanical properties of fasteners - Part 7: Torsional test and minimum torques for bolts and screws with nominal diameters 1 mm to 10 rnm I Scope This pari of IS0 898 specifies a torsional test lor the determination of the breaking torque of bolts and screws with nominal diameters 1 mm to i0 mm
23、 with property classes 8.8 to 12.9 in accordance with IS0 898-1. The test applies to bolts and screws with thread less than M3 foi- which no breaking and proof loas are indicated in IS0 898-1, as well as to short bolts and screws with nominal diameters 3 mm to 10 mm which cannot be subjected to a te
24、nsile test. The minimum breaking torques are not valid for hexagon socket set screws. 2 Normative reference The following standard contains provisions which, through reference in this text. constitute provisions o this part of IS0 898. At the time of publication, the edition indicated was valid. All
25、 standards are sub- ject to revision, and parties to agreements based on this part of IS0 898 are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and IS0 maintain registers of currently valid Inter- national Standards. IS0
26、 898-1: 1988, Mechanical properties of fasteners - Part I: Bolts, screws and studs. 3 Torsional test 3.1 Principie Determination of the breaking torque by clamping the bolt or screw io be tested into a test device. 3.2 Apparatus 3.2.1 Test device for torsional test, such as is shown in figure 1. 3.2
27、.2 Torquemeter, with a scale which shall not ex- ceed the quintuple of the respective minimum breaking torque. Tne maximum inaccuracy of the torquemeter shall be 7 ?/o of the minimum break- ing torque to be tested. 3.3 Test conditions The bolt or screw shall be exclusively subjected to torsion where
28、by the respective minimum breaking torque according to table 2 shall be reached before rupture occurs. The test result shall not be influ- enced by head friction or .by thread friction. 3.4 Procedure Clamp the bolt or screw into the test device over at least two full threads$ having a free thread le
29、ngth of at least one thread diameter present between the head of the bolt or screw and the threaded insert (see figure 1). Apply the torque in a continuously in- creasing manner. COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesCEN ENM20898-7 95 3404589 009398
30、3 T40 Page 4 EN 2089 is the torsionai strength; is the polar moment of resistance; is the minimum value of the minor di- ameter of the external thread; is the tensile strength; and is the strength ratio rB/Rrn (see table I). 5 Evaluation of the torque test The tested bolt or screw is regarded as hav
31、ing passed the torque test if no rupture occurs before the minimum breaking torques specified in table 2 are reached. Figure 1 - Example of a device for the torsional test COPYRIGHT European Committee for StandardizationLicensed by Information Handling ServicesPage 5 EN 2089 Fax: O181 996 7001. In r
32、esponse to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and international standards thr
33、ough its Library, the Standardline Database, the BSI Information Technology Service (BITS) and its Technical Help to Exporters Service. Contact the Information Department at Chiswick: Tel: O181 996 7111; Fax: O181 996 7048. Subscribing memberc of BSI are kept up to date with standards developments a
34、nd receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Customer Services, Membership at Chiswick: Tel: O181 996 7002; fix: O181 996 7001. Copyright Copyright subsists in all BSI publications and no part may be reproduced in any form witho
35、ut the prior permission in writing of BSI. This does not preclude the free use, in the course of implementing the standard of necessary details such as symbols and size, type or grade designations including use by incorporation into computer programs, but where these details are reproduced including
36、 without limitation in printed form, in computer programs or in any other form whatsoever, the permission in writing of BSI must be obtained and if granted will be on terms including royalty, before the product is sold, licensed or otherwise exploited for commercial gain. Enquiries about copyright should be made to the Copyright Manager at Chiswick. ISBN O 680 24385 O Product code 00540502 GME/9 COPYRIGHT European Committee for StandardizationLicensed by Information Handling Services
