1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationPrevailing torque typeall-metal hexagon nuts, style 2 Property class 9BS ISO 7720:2012National forewordThis British Standard is the UK implementation of ISO 7720:2012. It superse
2、des BS ISO 7720:1997 which is withdrawn.The UK participation in its preparation was entrusted by Technical Committee FME/9, Fasteners, to Subcommittee FME/9/1, Fasteners - Mechanical properties.A list of organizations represented on this committee can be obtained on request to its secretary.This pub
3、lication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012Published by BSI Standards Limited 2012 ISBN 978 0 580 77985 5 ICS 21.060.20Compliance with a British Standard cannot confer immun
4、ity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2012.Amendments issued since publicationDate Text affectedBRITISH STANDARDBS ISO 7720:2012 ISO 2012Prevailing torque type all-metal hexagon nuts, style 2 Prope
5、rty class 9crous hexagonaux autofreins tout mtal, style 2 Classe de qualit 9INTERNATIONAL STANDARDISO7720Third edition2012-06-01Reference numberISO 7720:2012(E)BS ISO 7720:2012ISO 7720:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise sp
6、ecified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeC
7、ase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 7720:2012ISO 7720:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member
8、 bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental
9、 and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directive
10、s, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies ca
11、sting a vote.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 any or all such patent rights.ISO 7720 was prepared by Technical Committee ISO/TC 2, Fasteners, Subcommittee SC 12, Fas
12、teners with metric internal thread.This third edition cancels and replaces the second edition (ISO 7720:1997), which has been technically revised. ISO 2012 All rights reserved iiiBS ISO 7720:2012Prevailing torque type all-metal hexagon nuts, style 2 Property class 91 ScopeThis International Standard
13、 specifies the characteristics of prevailing torque type all-metal hexagon nuts, of style 2, with threads from M5 up to and including M36, in product grade A for threads up to and including M16, and product grade B for threads over M16, and with property class 9.NOTE 1 The dimensions of the nuts, wi
14、th the exception of the dimensions mwand hmax, correspond to those given in ISO 4033.NOTE 2 Nuts of property classes 5, 8, 10 and 12 are dealt with in ISO 7042.If other specifications are required, they can be selected from existing International Standards, for example ISO 261, ISO 724, ISO 898-2, I
15、SO 965-2, ISO 2320 and ISO 4759-1.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) ap
16、plies.ISO 225, Fasteners Bolts, screws, studs and nuts Symbols and descriptions of dimensionsISO 261, ISO general purpose metric screw threads General planISO 724, ISO general-purpose metric screw threads Basic dimensionsISO 898-2, Mechanical properties of fasteners made of carbon steel and alloy st
17、eel 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 2320, Prevailing torque type steel hexagon nuts Mechani
18、cal and performance propertiesISO 3269, Fasteners Acceptance inspectionISO 4042, Fasteners Electroplated coatingsISO 4759-1, Tolerances for fasteners Part 1: Bolts, screws, studs and nuts Product grades A, B and CISO 6157-2, Fasteners Surface discontinuities Part 2: NutsISO 8992, Fasteners General r
19、equirements for bolts, screws, studs and nutsISO 10683, Fasteners Non-electrolytically applied zinc flake coatingsINTERNATIONAL STANDARD ISO 7720:2012(E) ISO 2012 All rights reserved 1BS ISO 7720:2012ISO 7720:2012(E)3 DimensionsFor dimensions, see Figure 1 and Table 1.Symbols and descriptions of dim
20、ensions are specified in ISO 225.aPrevailing torque element; shape is at the discretion of the manufacturer.b = 15 to 30.c = 90 to 120.Figure 1Table 1 DimensionsDimensions in millimetresThreadDM5 M6 M8 M10 M12 (M14)aM16 M20 M24 M30 M36Pb0,8 1 1,25 1,5 1,75 2 2 2,5 3 3,5 4damax. 5,75 6,75 8,75 10,80
21、13,00 15,10 17,30 21,60 25,90 32,40 38,90min. 5,00 6,00 8,00 10,00 12,00 14,00 16,00 20,00 24,00 30,00 36,00dwmin. 6,88 8,88 11,63 14,63 16,63 19,64 22,49 27,70 33,25 42,75 51,11e min. 8,79 11,05 14,38 17,77 20,03 23,36 26,75 32,95 39,55 50,85 60,79hmax. 5,30 6,70 8,00 10,50 13,30 15,40 17,90 21,80
22、26,40 31,80 38,50min. 4,80 5,40 7,14 8,94 11,57 13,40 15,70 19,00 22,60 27,30 33,10mwcmin. 3,84 4,32 5,71 7,15 9,26 10,70 12,60 15,20 18,10 21,80 26,50s max. 8,00 10,00 13,00 16,00 18,00 21,00 24,00 30,00 36,00 46,00 55,00min. 7,78 9,78 12,73 15,73 17,73 20,67 23,67 29,16 35,00 45,00 53,80aThe size
23、in parentheses (brackets) should be avoided, if possible.bP is the pitch of the thread.cMinimum wrenching height.2 ISO 2012 All rights reservedBS ISO 7720:2012ISO 7720:2012(E)4 Requirements and reference International StandardsSee Table 2.Table 2 Requirements and reference International StandardsMat
24、erial SteelGeneral requirements International Standard ISO 8992ThreadTolerance class 6HInternational Standards ISO 261, ISO 724, ISO 965-2Mechanical and performance propertiesProperty class 9International Standard ISO 898-2, ISO 2320ToleranceProduct gradeFor D M16: AFor D M16: BInternational Standar
25、d ISO 4759-1Finish CoatingAs processedRequirements for electroplating are specified in ISO 4042.Requirements for non-electrolytically applied zinc flake coatings are specified in ISO 10683.Additional requirements or other finishes or coatings shall be agreed between the supplier and the purchaser.Su
26、rface integrity Limits for surface discontinuities are specified in ISO 6157-2.Acceptability Acceptance inspection is specified in ISO 3269.5 DesignationEXAMPLE A prevailing torque type all-metal hexagon nut, of style 2, with thread M12 and property class 9 is designated as follows:Prevailing torque
27、 type hexagon nut ISO 7720 - M12 - 9 ISO 2012 All rights reserved 3BS ISO 7720:2012ISO 7720:2012(E)Bibliography1 ISO 4033, Hexagon nuts, style 2 Product grades A and B2 ISO 7042, Prevailing torque type all-metal hexagon nuts, style 2 Property classes 5, 8, 10 and 124 ISO 2012 All rights reservedBS I
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