1、BRITISH STANDARD AEROSPACE SERIES Inserts, screw thread, helid coil, self-locking - Technical specification The European Standard EN 2943:1998 has the status of a British Standard ICs 49.030.30 BS EN 2943:1998 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW STD-BSI BS EN 29Li3
2、-ENGL 1998 = Lb24bb7 0737807 OLL direction of the Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 November 1998 Amd. No. BS EN 2943:1998 Date Text affected National foreword This British Standard is the English language version o
3、f EN 2943.1998. The UK participation in its preparation was entrusted by Technical Committee ACW12, Aerospace fasteners and fastening systems, to Subcommittee ACWlYl, Aerospace fasteners and fastening systems (international), which has the responsibility to: - aid enquirem to understand the text; -
4、present to the responsible internationavEuropean committee any enquiries on the 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
5、can be obtained on request to its secretaty. Cross-references The British Standards 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 t
6、he “Find” facility of the BSI Standarcis Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract Users of Briish Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from
7、 legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN tide page, pages 2 to 16, an inside back cover and a back cover. O BSI 1998 ISBN O 680 30774 3 I I STD-BSI BS EM 2943-ENGL 1998 W Lb24bb7 073780d T5A EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE
8、 NORM EN 2943 September 1998 ICs 49.030.30 Descriptors: aircraft industry, screw thread, seClocking screw thread, definition, quality assurance, acceptance testing, specification, characteristic English version Aerospace series - Inserts, screw thread, helical coil, self- locking - Technical specifi
9、cation Srie arospatiale - Filets rapports. freinage interne - SpcHication technique Luft- und Raumfahrt - Draht-Gewindeeinstze, selbstsichemd - Technische Lieferbedingungen This European Sandard was approved by CEN on 23 February 1998. CEN members are bound to comply with lhe CEWCENELEC Internal Reg
10、ulations which stipulate the conditions for giving this European Standard aie status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be abteined on application to the Central Secretariat or to any CEN member. This
11、European Siandard exists in three officiai venions (English, French, German). A venion in any other language made by translation under aie responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official CEN members are the national sta
12、ndards bodies of Austria. Belgium, Czech Republic, Denmaik, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netheriands, Norway, Portugal. Spain, Sweden, Switzerland and United Kingdom. - i - versions. e - - _. - - E EUROPEAN COMMllTEE FOR STANDARDIZATION COMITE EUROPBEN DE NO
13、RMALISATION EUROPAISCHES KOMITEE FOR NORMUNG Central Secretariat: rue de Stassart, 36 8-1050 Brussels Q 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 29431998 E STD.BSI BS EN 2793-ENGL 2778 Lb24bbS 0737807 974 Page 2 EN 2%3:
14、1998 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, this Standard has received the approval of the National Associations and the Official Service
15、s of the member countries of AECMA, prior to its presentation to GEN. 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 March 1999, and conflicting national standards shall be withdrawn at the lates
16、t by March 1999. According to the CEWCENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Gemany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlan
17、ds, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents list 1 scope 2 Normative references 3 efinltions 4 Quality assurance 5 Requirements Annex A (nomative) Definition of maximum and minimum mandrels for the permanent set test Annex B (normatie) Assembly for reusability t
18、ests Annex C (normative) eflnition of test boit for reusability tests Annex D (normative) Definition of spacer for reusability tests * * m STD.BSI BS EN 27Li3-ENGL 1778 Lb2qbb7 0737810 bob m Page 3 EN 2943:1998 1 Scope This standard specifies the characteristics, qualification and acceptance require
19、ments 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 references This European Standard incorporates by dated or undated reference provisions from other publications. These normative refe
20、rences 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 these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the
21、 latest edition of the publication referred to applies. IS0 2859-1 IS0 3353 IS0 3534-1 977 IS0 4288 IS0 5855-2 EN 2398 EN 2404 EN 2945 EN 3042 EN 3044 Sampling procedures for inspection by attributes - Part 1 : Sampling plans indexed by acceptable quality level (AQL) for lot-by-lot inspection Aerosp
22、ace - Rolled threads for bolts - Lead and runout requirements Statistics - Vocabulary and symbols Rules and procedures for the measurement of surface roughness using stylus instruments Aerospace - MJ threads - Part 2: Limit dimensions for bolts and nuts HeatresistingsteelFE-PA92-HT-Fm1900MPa-Baisfor
23、machinedbolts-Ds25mm- Aerospace series 1) Heat resisting nickel base alloy NI-PI -HT - Solution treated and precipitation treated - Bars - Aerospace series 1) Aerospace series - Inserts, screw thread, helical coil, self-locking - Assembly procedure 2) Aerospace Cenes - Quality assurance - EN aerospa
24、ce products - Qualification procedure Aerospace series - Installation holes and procedures for inserts, screw thread, helical coil, self-locking - Design standard 2) 1) Published as AECMA Standard at the date of publication of this standard 2) Published as AECMA Prestandard at the date of publicatio
25、n of this standard STD-BSI BS EN 2943-ENGL 1778 9 16246b9 0737833 542 Page 4 EN 2943:1998 3 Definitions 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 sa
26、me melt, manufactured in the course of the same production cycle, following the same manufacturing 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 in
27、tercrystalline or transcrystalline in character 3.2.2 Seam: open surface defect 3.2.3 Lap: surface defect caused by folding over metal fins or sharp comers and then compressing them into the surface 3.2.4 Inclusions: non-metallic particles originating from the material manufacturing process. These p
28、articles may be isolated or arranged in strings. 3.3 Test temperature Ambient temperature, unless othennrise specified 3.4 Simple random sampling The taking of n items from a population of Nitems in such a way that all possible combinations of n items have the same probability of being chosen 3) 3.5
29、 Critical defect A defect that, according to judgement and experience, is likely to result in hazardous 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) 3.6 Major defect
30、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 3) 3.7 Minor defect A defect that is not likely to reduce materially the usability of the considered product for its intended purpose, or that
31、is a departure from established specification having lile bearing on the effective use or operation of this product 3) 3.8 Sampling pian A plan according to which one or more samples are taken in order to obtain information and possibly to reach a decision 3) 3.9 Limiting quality In a sampling plan,
32、 the quality level which corresponds to the specified 10 YO probability of acceptance * m * STD-BSI BS EN 2743-ENLL 1998 Lb24bb7 0737832 489 Page 5 EN 2943:1998 3.1 O Acceptable quality level (AQL) A quality level which in a sampling plan corresponds to a specified but relatively high probability of
33、 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 3). 3.1 1 Finished thread insert A thread insert ready for use, inclusive of any possible treatments and
34、/or surface coatings, as specified in the product standard or definition document 3.1 2 Definition document Document specifying all the requirements for finished thread inserts 3.1 3 Self-locking torque The torque to be applied to the associated bolt to maintain its movement of rotation in relation
35、to the thread insert assembly which is under no axial load and the thread inseri locking zone being completely engaged with the bolt (minimum protrusion of two pitches, including the end chamfer) 3.1 4 Seating torque The tightening torque to be applied to the thread insert and bolt assembly to intro
36、duce or to increase the axial load in the assembly 3.1 5 Unseating torque The untightening toque to be applied to the thread insert and boit assembly to reduce or remove the axial load in the assembly 3.1 6 Breakaway torque The torque required to start unscrewing the associated bolt with respect to
37、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 3) Definition taken from IS0 3534 STD-BSI BS EN 29q3-ENGL 1998 Lb2LibbS 0737833 335
38、 = Page 6 EN 2943: 1998 4 Quality assurance 4.1 Qualification EN 3042 Qualification inspections and tests (requirements, methods, numbers of thread inserts) are specified in table 1. They shall be carried oui on: - each type and diameter of thread insert; - 26 thread inserts selected from a single b
39、atch by simple random sampling. The test programme may possibly be reduced, or the 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 mdtions are
40、identical. Table 2 indicates the allocation of thread insert specimens for the 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
41、 statistical sampling, that the thread inserts constituting the batch satisfy the 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
42、 the batch to be tested shall be selected by simple random sampling. 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 t
43、esting. In this case, 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 oui by the manufacturer, or under his responsibility. 4.2.4 Inspect
44、ion and test report A test report showing actual numerical values shall be provided if specified in the purchase order. 5 Requirements See table 1. STD-BSI BS EN 2743-ENGL 1778 Lb24bb7 0737814 251 Dimensions, tokames and takrancasof Iforniand podtion Page 7 EN 2943:1998 Permanent set test (ambient I
45、 temperature) Table 1 : Technical requirements and test methods Measured torques of the thread inserts shall not exceed the maximum self-locking toque nor shall be less than the minimum breakaway toque, see table 5. When screwing and unscrewing the maximum and minimum mandrels, the rotation of the t
46、hread insert in its location shall not exceed f 90“. , When screwing and unscrewing the boit, the rotation of the thread insert in its location shall not exceed f 90. Clause I Chamceristlc I Requirement 5.1 Material In accordance with the product standard or definition document 5.2 In accordance wit
47、h the product standard or definition document Manufauring 5.3.1 Surface In accordance with the product roughness standard or definition document 5.3.2 In accordance with the product coatina standard or definition document 5.4 5.4.1 i.4.2 Mwhanial Thread inserts shall be assembled into test equipment
48、 according to I prope*s I EN 2945 see table 41. Reusability test Inspection and test method Chemical analysis or certificate of compliance issued by the manufacturer oi the semi-finished Product Standard gauging IS0 4288 Visual examination See applicable coating standard. Lubricate the maximum mandr
49、el using clean engine oil. Fit the maximum mandrel in the thread insert, until it protrudes at leasi 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 sequence of operations using the minimum mandrel, measuting the breakaway toque. Check that the mandrel dimensions are within the limits given in annex A and that their threads have not been damaged. The rotation of the mandrels shall be sufficiently s
