1、BRITISH STANDARD AEROSPACE SERIES BS EN 2943:1998 Inserts, screw thread, helical coil, self-locking Technical specification The European Standard EN2943:1998 has the status of a British Standard ICS 49.030.30BSEN2943:1998 This British Standard, having been prepared under the directionof the Engineer
2、ing SectorCommittee, was publishedunder the authority ofthe Standards Committee andcomesinto effect on 15 November1998 BSI 06-1999 ISBN 0 580 30774 3 National foreword This British Standard is the English language version of EN2943:1998. The UK participation in its preparation was entrusted by Techn
3、ical Committee ACE/12, Aerospace fasteners and fastening systems, to Subcommittee ACE/12/1, Aerospace fasteners and fastening systems (International), which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on t
4、he interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Stand
5、ards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standar
6、d does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an
7、 inside front cover, pages i and ii, theEN title page, pages2 to14 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Dat
8、e CommentsBSEN2943:1998 BSI 06-1999 i Contents Page National foreword Inside front cover Foreword 2 Text of EN 2943 3ii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 2943 September 1998 ICS 49.030.30 Descriptors: Aircraft industry, screw thread, self-locking screw thread, definition, qua
9、lity assurance, acceptance testing, specification, characteristic English version Aerospace series Inserts, screw thread, helical coil, self-locking Technical specification Srie arospatiale Filets rapports, freinage interne Spcification technique Luft- und Raumfahrt Draht-Gewindeeinstze, selbstsiche
10、rnd Technische Lieferbedingungen This European Standard was approved by CEN on23 February1998. CEN members 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-da
11、te 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 version in any other language made by translation under the
12、 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, CzechRepublic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg
13、, 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 1998 CEN All rights of exploitation in any form and by any
14、 means reserved worldwide for CEN national Members. Ref.No.EN2943:1998EEN2943:1998 BSI 06-1999 2 Foreword This European Standard has been prepared by the European Association of Aerospace Manufacturers (AECMA). After inquiries and votes carried out in accordance with the rules of this Association, t
15、his Standard has received the approval of the National Associations and the Official Services of the member countries of AECMA, prior to its presentation to CEN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at
16、the latest by March1999, and conflicting national standards shall be withdrawn at the latest by March1999. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, CzechRepublic
17、, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and theUnitedKingdom. Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Definitions 3 4 Quality assurance 4 5 Requirements 5 Annex A (normative) Def
18、inition of maximum and minimum mandrels for thepermanent set test 12 Annex B (normative) Assembly for reusability tests 13 Annex C (normative) Definition of test bolt for reusability tests 13 Annex D (normative) Definition of spacer for reusability tests 14 Figure A.1 12 Figure B.1 13 Figure C.1 13
19、Figure D.1 14 Table 1 Technical requirements and test methods 6 Table 2 Allocation of qualification testingrequirements 9 Table 3 Sampling plans 10 Table 4 Test equipment 10 Table 5 Values of breakaway torque, self-locking torque and seating torque 11 Table 6 Test blocks 11 Table A.1 12 Table C.1 14
20、 Table D.1 14EN2943:1998 BSI 06-1999 3 1 Scope This standard specifies the characteristics, qualification and acceptance requirements for self-locking helical coil screw thread inserts in NI-PH2801 or FE-PA3004, with or without surface coating. It is applicable whenever referenced. 2 Normative refer
21、ences This European Standard incorporates by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of thes
22、e publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. ISO 2859-1, Sampling procedures for inspection by attributes Part1: Sampling plans indexed by acceptable quality lev
23、el (AQL) for lot-by-lot inspection. ISO 3353, Aerospace Rolled threads for bolts Lead and runout requirements. ISO 3534-1977, Statistics Vocabulary and symbols. ISO 4288, Rules and procedures for the measurement of surface roughness using stylus instruments. ISO 5855-2, Aerospace MJ threads Part2: L
24、imit dimensions for bolts and nuts. EN 2398, Heat resisting steel FE-PA92-HT R m$ 900 MPa Bars for machined bolts D # 25 mm Aerospace series 1) . EN 2404, Heat resisting nickel base alloy NI-P100-HT Solution treated and precipitation treated Bars Aerospace series 1) . EN 2945, Aerospace series Inser
25、ts, screw thread, helical coil, self-locking Assembly procedure 2) . EN 3042, Aerospace Series Quality assurance EN aerospace products Qualification procedure. EN 3044, Aerospace series Installation holes and procedures for inserts, screw thread, helical coil, self-locking Design standard 2) . 3 Def
26、initions For the purposes of this standard, the following definitions apply: 3.1 batch quantity of finished thread inserts, of the same type and same diameter, produced from a material obtained from the same melt, manufactured in the course of the same production cycle, following the same manufactur
27、ing route and having undergone all the relevant heat treatments and surface treatments 3.2 Surface discontinuities 3.2.1 crack rupture in the material which may extend in any direction and which may be intercrystalline or transcrystalline in character 3.2.2 seam open surface defect 3.2.3 lap surface
28、 defect caused by folding over metal fins or sharp corners and then compressing them into the surface 3.2.4 inclusions non-metallic particles originating from the material manufacturing process. These particles may be isolated or arranged in strings 3.3 test temperature ambient temperature, unless o
29、therwise specified 3.4 simple random sampling the taking of n items from a population of N items in such a way that all possible combinations of n items have the same probability of being chosen 3) 3.5 critical defect a defect that, according to judgement and experience, is likely to result in hazar
30、dous or unsafe conditions for individuals using, maintaining, or depending upon the considered product, or that is likely to prevent performance of the function of a major end item 3) 1) Published as AECMA Standard at the date of publication of this standard 2) Published as AECMA Prestandard at the
31、date of publication of this standard 3) Definition taken from ISO3534EN2943:1998 4 BSI 06-1999 3.6 major defect a defect other than critical, that is likely to result in a failure or to reduce materially the usability of the considered product for its intended purpose 4) 3.7 minor defect a defect th
32、at is not likely to reduce materially the usability of the considered product for its intended purpose, or that is a departure from established specification having little bearing on the effective use or operation of this product 4) 3.8 sampling plan a plan according to which one or more samples are
33、 taken in order to obtain information and possibly to reach a decision 4) 3.9 limiting quality in a sampling plan, the quality level which corresponds to the specified 10% probability of acceptance 3.10 acceptable quality level (AQL) a quality level which in a sampling plan corresponds to a specifie
34、d but relatively high probability of acceptance it is the maximum per cent defective (or the maximum number of defects per hundred units) that, for purposes of sampling inspection can be considered satisfactory as a process average 4) 3.11 finished thread insert a thread insert ready for use, inclus
35、ive of any possible treatments and/or surface coatings, as specified in the product standard or definition document 3.12 definition document document specifying all the requirements for finished thread inserts 3.13 self-locking torque the torque to be applied to the associated bolt to maintain its m
36、ovement of rotation in relation to the thread insert assembly which is under no axial load and the thread insert locking zone being completely engaged with the bolt (minimum protrusion of two pitches, including the end chamfer) 3.14 seating torque the tightening torque to be applied to the thread in
37、sert and bolt assembly to introduce or to increase the axial load in the assembly 3.15 unseating torque the untightening torque to be applied to the thread insert and bolt assembly to reduce or remove the axial load in the assembly 3.16 breakaway torque the torque required to start unscrewing the as
38、sociated bolt with respect to the installed thread insert, with the insert locking zone still fully engaged on the bolt, but after the axial load in the assembly has been removed by unscrewing half a turn followed by a halt in rotational movement 4 Quality assurance 4.1 Qualification EN3042 Qualific
39、ation inspections and tests (requirements, methods, numbers of thread inserts) are specified in Table 1. They shall be carried out on: each type and diameter of thread insert; 26 thread inserts selected from a single batch by simple random sampling. The test programme may possibly be reduced, or the
40、 qualification be granted without inspection or testing: any such decision shall be based on the results obtained on similar types and diameters of thread inserts provided that the design and manufacturing conditions are identical. Table 2 indicates the allocation of thread insert specimens for the
41、inspections and tests. 4.2 Acceptance 4.2.1 Purpose The purpose of acceptance inspections and tests is to check, as simply as possible, by a method representative of actual use conditions, with the uncertainty inherent to statistical sampling, that the thread inserts constituting the batch satisfy t
42、he requirements of this standard. 4.2.2 Conditions Acceptance inspections and tests (requirements, methods, numbers of thread inserts) are specified in Table 1. They shall be carried out on each batch. Thread inserts from the batch to be tested shall be selected by simple random sampling. 4) Definit
43、ion taken from ISO3534EN2943:1998 BSI 06-1999 5 Each thread insert may be submitted to several inspections or tests. If a more stringent inspection is deemed necessary, all or part of the qualification inspections and tests may be performed during the acceptance inspection and testing. In this case,
44、 the number of thread inserts submitted to these inspections and tests is the same as that submitted for qualification inspection and tests. 4.2.3 Responsibility Acceptance inspections and tests shall be carried out by the manufacturer, or under his responsibility. 4.2.4 Inspection and test report A
45、 test report showing actual numerical values shall be provided if specified in the purchase order. 5 Requirements See Table 1. EN2943:1998 6 BSI 06-1999 Table 1 Technical requirements and test methods Clause Characteristic Requirement Inspection and test method Q/A a Sample size 5.1 Material In acco
46、rdance with the product standard or definition document Chemical analysis or certificate of compliance issued by the manufacturer of the semi-finished product Q A 5.2 Dimensions, tolerances and tolerances of form and position In accordance with the product standard or definition document Standard ga
47、uging Q 26 A Table 3 5.3 Manufacturing 5.3.1 Surface roughness In accordance with the product standard or definition document ISO4288 Visual examination Q 3 A Table 3 5.3.2 Surface coating In accordance with the product standard or definition document See applicable coating standard. Q 23 A Table 3
48、5.4 Mechanical properties Thread inserts shall be assembled into test equipment according to EN2945 (see Table 4). 5.4.1 Permanent set test (ambient temperature) Measured torques of the thread inserts shall not exceed the maximum self-locking torque nor shall be less than the minimum breakaway torqu
49、e, seeTable 5. When screwing and unscrewing the maximum and minimum mandrels, the rotation of the thread insert in its location shall not exceed 90. Lubricate the maximum mandrel using clean engine oil. Fit the maximum mandrel in the thread insert, until it protrudes at least two pitches beyond the locking zone of the thread insert, measuring the self-locking torque on screwing. Unscrew, removing the maximum mandrel completely from the thread insert. Carry out the same chronological sequ
