1、BRITISH STANDARDBS EN 2786:2008Aerospace series Electrolytic silver plating of fastenersICS 49.030.01g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g5
2、8Licensed Copy: :FULLNAME, : DATE, Uncontrolled Copy, (c) BSIBS EN 2786:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2008 BSI 2008ISBN 978 0 580 60314 3National forewordThis British Standard is the UK implementation of EN 2786
3、:2008.The UK participation 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 provis
4、ions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate CommentsLicensed Copy: :FULLNAME, : DATE, Uncontrolled Copy, (c) BSIEUROPEAN STANDARDNORME EUROPEN
5、NEEUROPISCHE NORMEN 2786March 2008ICS 49.030.01English VersionAerospace series - Electrolytic silver plating of fastenersSrie arospatiale - Argentage lectrolytique des lmentsde fixationLuft- und Raumfahrt - Elektrolytisches Versilbern vonVerbindungselementenThis European Standard was approved by CEN
6、 on 12 December 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards m
7、ay be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CE
8、N Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,
9、 Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any for
10、m and by any means reservedworldwide for CEN national Members.Ref. No. EN 2786:2008: ELicensed Copy: :FULLNAME, : DATE, Uncontrolled Copy, (c) BSI2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Purpose of process .4 4 Technical requirement 4 5 Required characteristics.5 6 Classificati
11、on of tests6 7 Quality assurance6 BS EN 2786:2008Licensed Copy: :FULLNAME, : DATE, Uncontrolled Copy, (c) BSI3 Foreword This document (EN 2786:2008) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-STAN). After enquiries and votes carried out in
12、accordance with the rules of this Association, this Standard has received the approval of the National Associations and the Official Services of the member countries of ASD, prior to its presentation to CEN. This European Standard shall be given the status of a national standard, either by publicati
13、on of an identical text or by endorsement, at the latest by September 2008, and conflicting national standards shall be withdrawn at the latest by September 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC
14、shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark,
15、Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 2786:2008Licensed Copy: :FULLNAME, : DATE, Uncontrolled Copy
16、, (c) BSI4 1 Scope This standard specifies the electrolytic silver plating of fasteners used in aerospace applications. It shall apply whenever referenced. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the
17、 edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 2828, Aerospace series Adhesion test for metallic coatings by burnishing. EN 2830, Aerospace series Adhesion test for metallic coatings by shearing action. EN 2831, Ae
18、rospace series Hydrogen embrittlement of steels Test by slow bending. EN 2832, Aerospace series Hydrogen embrittlement of steels Notched specimen test. EN 9100, Aerospace series Quality management systems Requirements (based on ISO 9001:2000) and Quality systems Model for quality assurance in design
19、, development, production, installation and servicing (based on ISO 9001:1994). 3 Purpose of process To prevent galling or seizure. 4 Technical requirement 4.1 Preparation Parts shall have chemically and/or electrolytically clean surfaces prepared with minimum abrasion, erosion or pitting, prior to
20、immersion in the plating solution. Treatments which may produce hydrogen embrittlement shall be avoided. After cleaning and prior to immersion in the plating solution, parts may be etched in a suitable solution such as ferric chloride and/or hydrochloric acid, to promote adhesion. Electrical contact
21、 between the parts and the power source shall be established in such a manner as to ensure that neither chemical/immersion deposition nor electrical arcing or overheating will occur. 4.2 Procedure The parts shall be silver plated over a suitable nickel and/or silver strike by an approved method to t
22、he thickness quoted in the product standard or in the definition document. The plated parts shall be removed from the plating solution then thoroughly rinsed and dried. BS EN 2786:2008Licensed Copy: :FULLNAME, : DATE, Uncontrolled Copy, (c) BSI5 5 Required characteristics 5.1 Appearance The silver p
23、late shall be sound, smooth, continuous, uniform in color and free from blisters and other imperfections (see 5.4.2). Abrasion of plating on corners and edges of threaded fasteners is acceptable, but plate shall be continuous on the threads. Marking of the cone section of self-locking nuts, produced
24、 in off-setting the locking beams or other deformation, is acceptable. 5.2 Composition Silver as plated shall be not less than 99,9 % pure, the process of plating shall be controlled to produce this purity. 5.3 Post treatments De-embrittlement is mandatory on martensitic steel where the tensile stre
25、ngth can exceed 1 100 MPa. De-embrittlement, where applicable, shall be carried out as soon as possible, but no later than 16 h after plating, the time and temperature are optional. Where de-embrittlement is specified, the parts or test pieces shall be tested to EN 2831 or EN 2832 or parts shall be
26、subjected for 200 h at ambient temperature to an axial load equal to 75 % of the tensile strength of the part and must show satisfactory results. No fracture is permissible before 200 h. 5.4 Adhesion 5.4.1 General To be checked on parts or test pieces. These parts or test pieces shall be heated in a
27、ir to the following applicable temperature held at temperature within 8 C for no less than two hours and cooled in still air. a) Parts with a maximum test temperature of up to and including 425 C: The temperature of any de-embrittlement shall be considered sufficient. If no de-embrittlement is carri
28、ed out, the temperature shall be the maximum test temperature of the parts. b) Parts with a maximum test temperature of more than 425 C: The temperature shall be the maximum test temperature of the parts. 5.4.2 Adhesion requirements After heating, parts or test pieces shall be visually examined at 1
29、0 times magnification. Parts shall be free of detrimental blisters and of indications of poor bond such as flaking and lifting of the plating. Some small blisters are acceptable provided the parts meet the adherence requirements. Blisters 0,38 mm and larger in diameter, are not acceptable. After vis
30、ual examination, the parts or test pieces shall be subjected to one of the following adhesion tests, EN 2828, EN 2830 or any other adhesion test that is agreed. BS EN 2786:2008Licensed Copy: :FULLNAME, : DATE, Uncontrolled Copy, (c) BSI6 6 Classification of tests 6.1 Acceptance tests The following t
31、ests shall be carried out on each lot: a) Appearance (see 5.1); b) Thickness (as defined on the product standard or definition document) to be measured by an agreed method; c) Adhesion (see 5.4, 5.4.2). NOTE A lot shall be all parts of the same size and shape, made of the same alloy, plated to the s
32、ame thickness in the same set of solutions within one 24 h period. 6.2 Periodic tests The following tests shall be performed at a frequency selected by the process controller: a) Composition (see 5.2); b) Post treatments (see 5.3). 7 Quality assurance EN 9100. BS EN 2786:2008Licensed Copy: :FULLNAME
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