1、BS ISO 8642:2008 ICS 49.030.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BRITISH STANDARD Aerospace Self- locking nuts with maximum operating temperature greater than 425 degrees C Test methodsThis British Standard was published under the authority of the Standards Polic
2、y and Strategy Committee on 3 ember 2008 BSI 2008 ISBN 978 0 580 55581 7 Amendments/corrigenda issued since publication Date Comments BS ISO 8642:2008 National foreword This British Standard is the UK implementation of ISO 8642:2008. It supersedes BS A 298:1988 which is withdrawn. The UK participati
3、on in its preparation was entrusted to Technical Committee ACE/12, Aerospace fasteners and fastening systems. 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. Us
4、ers are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. 1 DecBS ISO 8642:2008Reference number ISO 8642:2008(E) ISO 2008INTERNATIONAL STANDARD ISO 8642 Second edition 2008-09-01 Aerospace Self-locking nuts with maximum operati
5、ng temperature greater than 425 C Test methods Aronautique et espace crous freinage interne dont la temprature maximale dutilisation est suprieure 425 C Mthodes dessai BS ISO 8642:2008 ISO 8642:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing p
6、olicy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobes licensing policy. The ISO Centr
7、al Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been take
8、n to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2008 All rights reserved. Unless otherwise specified, no part of this p
9、ublication 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 office Case postale 56 CH-1211 G
10、eneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reservedBS ISO 8642:2008 ISO 8642:2008(E) ISO 2008 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Inspections and
11、tests . 1 3.1 Hardness test 1 3.2 Bearing surface squareness test 2 3.3 Axial load test 4 3.4 Wrenching feature test. 5 3.5 Torque-out test 7 3.6 Test of no rotation of the captive washer 8 3.7 Push-out test . 9 3.8 Self-locking torque at ambient temperature 10 3.9 Self-locking torque at ambient tem
12、perature after heat soak at maximum operating temperature . 12 3.10 Permanent set test 15 3.11 Vibration test . 17 3.12 Swaging test 20 BS ISO 8642:2008 ISO 8642:2008(E) iv ISO 2008 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of nati
13、onal 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 subject for which a technical committee has been established has the right to be represented on that committee. Internat
14、ional organizations, governmental 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 ru
15、les given in the ISO/IEC Directives, 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
16、 least 75 % of the member bodies casting 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 8642 was prepared by Technical Committee ISO/TC
17、20, Aircraft and space vehicles, Subcommittee SC 4, Aerospace fastener systems. This second edition cancels and replaces the first edition (ISO 8642:1986) which has been technically revised. BS ISO 8642:2008 INTERNATIONAL STANDARD ISO 8642:2008(E) ISO 2008 All rights reserved 1 Aerospace Self-lockin
18、g nuts with maximum operating temperature greater than 425 C Test methods 1 Scope This International Standard specifies test methods for metric self-locking nuts with MJ threads intended for use in aerospace construction at maximum operating temperature greater than 425 C. It describes the test devi
19、ce and the method for each test. It applies to self-locking nuts as defined above, provided that the relevant documents (dimensional standard, drawing, procurement specification, etc.) refer to this International Standard. Other test devices or test methods than those specified in this International
20、 Standard may be used, but, in the event of a dispute, the requirements laid down in this International Standard shall take precedence. This International Standard shall be used in conjunction with ISO 8641. 2 Normative references The following referenced documents are indispensable for the applicat
21、ion of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 691, Assembly tools for screws and nuts Wrench and socket openings Tolerances for general use ISO 5855-2, Aerospac
22、e MJ threads Part 2: Limit dimensions for bolts and nuts ISO 6507-1, Metallic materials Vickers hardness test Part 1: Test method ISO 6508-1, Metallic materials Rockwell hardness test Part 1: Test method (scales A, B, C, D, E, F, G, H, K, N, T) ISO 7403, Aerospace Spline drives Wrenching configurati
23、on Metric series ISO 8641, Aerospace Self-locking nuts with maximum operating temperature greater than 425 C Procurement specification 3 Inspections and tests 3.1 Hardness test 3.1.1 Procedure The authorized procedures are: Rockwell hardness in accordance with ISO 6508-1; Vickers hardness HV 5 to HV
24、 100 in accordance with ISO 6507-1; BS ISO 8642:2008 ISO 8642:2008(E) 2 ISO 2008 All rights reserved Rockwell superficial hardness in accordance with ISO 6508-1; microhardness. It is strongly recommended to use the method corresponding to the hardness unit indicated. Should this not be possible, the
25、 use of conversion charts is allowed, but, given their inaccuracy, the results obtained shall be used warily. In the event of a dispute, the results obtained using the method corresponding to the hardness unit indicated shall take precedence. 3.1.2 Method This test shall be carried out at ambient te
26、mperature. The measurement zone (bearing surface, across flats, underside of anchor nut lugs, etc.) shall satisfy the following conditions: a) thickness at least equal to 10 the penetration depth; b) parallelism with respect to bearing surface no greater than 3. Should this not be possible, carry ou
27、t this test on a cut section after moulding the nut into a resin capable of maintaining it in the correct position. Remove all possible coating (protection, lubrication, paint, etc.) in the measurement zone. Align the bearing surface to obtain the required relationship. These two operations shall no
28、t generate any heat liable to modify the characteristics of the material constituting the nut being tested. Carry out the test and then check conformity with the requirements of the dimensional standard or drawing. Nuts subjected to this test shall not be used again. 3.2 Bearing surface squareness t
29、est 3.2.1 Test device The test device is illustrated in Figure 1 and includes the following elements: a) a threaded mandrel with end in accordance with ISO 5855-2, with the exception of the pitch diameter which shall be in accordance with the values specified in Table 5 for the maximum mandrel; b) a
30、 collar sliding on the plain portion of the threaded mandrel whose external diameter B is at least equal to reference dimension A for type I, III and VI nuts in Figure 2 and equal to reference dimension A for type II, IV and V nuts in Figure 2; c) an appropriate feeler gauge. 3.2.2 Method The test s
31、hall be carried out at ambient temperature. For floating nuts, extract the nut from the cage or channel. Lubricate the mandrel and nut threads (or threaded part) as stated in Table 1 (if necessary). Screw, with or without using a spanner, the threaded mandrel into the nut or threaded part until it e
32、ngages with the self- locking zone. Move the collar into contact with the bearing surface. BS ISO 8642:2008 ISO 8642:2008(E) ISO 2008 All rights reserved 3 Evaluate the out-of-squareness by means of a feeler gauge whose thickness corresponds to the permissible squareness error permitted by the dimen
33、sional standard, the drawing or the procurement specification. For clinch nuts, the sliding collar shall have a counterbore to accommodate the shank. Table 1 Test bolt and lubrication Nut to be tested Test bolt Material Coating Material Coating Additional lubrication Steel or alloy steel Any Alloy s
34、teel None Silver or MoS 2None Stainless steel None Stainless steel Silver Synthetic oil Key 1 sliding collar 2 threaded mandrel 3 feeler gauge aPitch diameter. Figure 1 Type I Type II Type III Type IV Type V Type VI Wrench nuts Clinch nuts Fixed anchor nuts Floating anchor nuts and gang channel nuts
35、 Figure 2 BS ISO 8642:2008 ISO 8642:2008(E) 4 ISO 2008 All rights reserved3.3 Axial load test 3.3.1 Test device The test device is illustrated in Figure 3 and includes the following elements: a) a steel bearing plate, heat-treated to a hardness W 40 HRC; b) a bolt with a rolled thread and the follow
36、ing characteristics: 1) threads in accordance with ISO 5855-2; 2) tensile strength class greater than that of the nut under test; 3) material and coating: no specific requirement; c) a torque wrench. 3.3.2 Method 3.3.2.1 Principle The axial load is transmitted to the nut by the bolt, the nut resting
37、 on the bearing plate. 3.3.2.2 80 % test This test shall be carried out at ambient temperature. Lubricate the bolt and nut threads as stated in Table 1 (if necessary). Assemble the bearing plate on the bolt. Assemble the nut and measure the locking torque, using the torque wrench, when the protrusio
38、n is two pitches minimum (including chamfer). Position the assembly on the tensile machine. Apply the load slowly and progressively. Reduce the load slowly and progressively when the value quoted in the procurement specification has been reached. Remove the assembly from the tensile machine. Unscrew
39、 the nut a half-turn and cease movement, then again unscrew and measure the breakaway torque, using the torque wrench. Remove the nut, then submit it to a visual examination and, if necessary, an examination at a magnification of 10 after sectioning, to check conformity with the requirements of the
40、procurement specification. BS ISO 8642:2008 ISO 8642:2008(E) ISO 2008 All rights reserved 5 Dimensions in millimetres Wrench nuts and non-floating anchor nuts Clinch nuts Floating anchor nuts and gang channel nuts aMaximum shank diameter. bChamfer to suit the nut radius. cHole to allow the specified
41、 float. d Loading direction.Figure 3 3.3.2.3 Test at ambient temperature and test at ambient temperature after maximum operating temperature baking (100 % test) This test shall be carried out at ambient temperature. If the test includes a heat soak, then heat the nut and maintain it at the temperatu
42、re quoted in the procurement specification. Take the nut from the oven and allow it to cool slowly to ambient temperature, then, in all cases, proceed as follows. Lubricate the bolt and nut threads as specified in Table 1 (if necessary), assemble the bearing plate on the bolt. Assemble the nut with
43、a protrusion of two bolt pitches minimum (including chamfer). Position the assembly on the tensile machine and apply the load slowly and progressively. Reduce the load slowly and progressively when the value quoted in the procurement specification has been reached. Remove the assembly from the tensi
44、le machine. Remove the nut, then submit it to a visual examination, and if necessary, an examination at a magnification of 10 after sectioning to check conformity with the requirements of the procurement specification. Nuts subjected to this test shall not be used again. 3.4 Wrenching feature test 3
45、.4.1 General This test applies only to wrenchable nuts. 3.4.2 Test device The test device is illustrated in Figure 4 and includes the following elements: a) a steel block, heat-treated to a hardness of W 40 HRC; BS ISO 8642:2008 ISO 8642:2008(E) 6 ISO 2008 All rights reservedb) a bolt with a rolled
46、thread and the following characteristics: 1) threads in accordance with ISO 5855-2; 2) tensile strength class: no specific requirement; 3) material and coating: no specific requirement; c) a torque wrench. NOTE Any other device that prevents the rotation of the nut and allows the specified torque to
47、 be applied is acceptable; for example: a nut welded on a block of the same material, the assembly being heat-treated to the correct level; nuts mounted in counter-rotation on a threaded rod of strength class appropriate to hold the required torques without deformation; a nut mounted on a bolt of st
48、rength class appropriate to hold the required torques without deformation as a spacer is placed between the nut and the bolt head. Dimensions in millimetres aWidth of slot equal to diameter of circle circumscribing the wrenching feature. bChamfer to suit underhead radius. cIncluding chamfer, where P
49、 is the pitch. dDepth of slot equal to flange height of nut under test. Figure 4 3.4.3 Method This test shall be carried out at ambient temperature. Make two flats on the flange of the nut so that it has a clearance of (0,05 to 0,1) mm inside the slot, lubricate the bolt and nut threads as specified in Table 1 (if necessary). Insert the modified nut into the slot. Assemble the bolt and moderately tighten it, then assemble the block into a vice. Repeat the following ope
