1、BRITISH STANDARD AEROSPACE SERIES BS EN 2831:1993 Hydrogen embrittlement of steels Test by slow bending The European Standard EN 2831:1993 has the status of a British Standard UDC 669.14:621.793794:620.177:629.7BSEN 2831:1993 This British Standard, having been prepared under the directionof the Aero
2、space Standards Policy Committee (ACE/-), was published under theauthority of the Standards Board and comes into effect on 15May1993 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference ACE/44 Draft for comment 90/75754 DC ISBN 0 580 22147 4 Cooperating o
3、rganizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following (CEN) countries: Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dans
4、k Standardiseringsraad Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland Ireland National Standards Authority of Ireland Italy E
5、nte Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y Certificacin Sweden Standardiseringskommissionen
6、 i Sverige Switzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBSEN 2831:1993 BSI 09-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN 2831 3
7、National annex NA (informative) Committees responsible Inside back coverBSEN 2831:1993 ii BSI 09-1999 National foreword This British Standard has been prepared under the direction of the Aerospace Standards Policy Committee and is the English language version of EN2831:1993, Aerospace series Hydroge
8、n embrittlement of steels Test by slow bending published by the European Committee for Standardization (CEN). EN 2831 was produced as a result of international discussion in which the United Kingdom took an active part. A British Standard does not purport to include all the necessary provisions of a
9、 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 inside front cover, pages i and ii, theEN title page, pages 2
10、to 6, an inside back cover 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.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 2831 February 1993 UDC 669.14:621.79
11、3/794:620.177:629.7 Descriptors: Aircraft industry, steels, hydrogen embrittlement, bend tests English version Aerospace series Hydrogen embrittlement of steels Test by slow bending Srie arospatiale Fragilisation des aciers par lhydrogne Essai par flexion lente Luft- und Raumfahrt Wasserstoffversprd
12、ung von Sthlen Langsamer Biegeversuch This European Standard was approved by CEN on 1993-02-19. 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-d
13、ate 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 th
14、e 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 organizations of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Nethe
15、rlands, 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 1993 Copyright reserved to CEN members Ref. No. EN 2831:1993 EEN
16、2831:1993 BSI 09-1999 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, this standard has successively received the approval of the National Assoc
17、iations 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 the latest by August 1993, and conflicting national standard
18、s shall be withdrawn at the latest by August 1993. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal
19、, Spain, Sweden, Switzerland and United Kingdom. Contents Page Foreword 2 1 Scope 3 2 Apparatus 3 3 Test specimens 3 4 Procedure 3 5 Expression of results 3 6 Fault sanction 3 7 Test report 4 Figure 1 Placing of the test specimen before testing 4 Figure 2 Bending angle prior to chemical or electroly
20、tic treatment 4 Figure 3 Bending angle after surface treatment 5 Figure 4 Bending angle after de-embrittlement 5EN 2831:1993 BSI 09-1999 3 1 Scope This standard specifies the test method by slow bending, which is used to assess the hydrogen embrittlement of steels during chemical or electrolytic sur
21、face treatments. This test is also used to verify the recovery of the initial ductility during de-embrittlement treatments. It is applicable whenever referenced. 2 Apparatus Bending test machine with the following characteristics: the chucks shall avoid any effects due to clamping in the region of c
22、racking, one of the chucks shall be fixed and the other movable; the fixed chuck shall be fitted with an interchangeable bending block the diameter of which may be between2mm and6mm (see Figure 1); the movable chuck shall have a deflection rate which can be adjusted between4 /min and18 /min, be fitt
23、ed with a device allowing to measure the angles ! o , ! f1and (! f2(see Figure 2 to Figure 4) with a precision of 0,5 , be fitted with a magnifier of10times in order to reveal the occurence of the first crack. 3 Test specimens They shall: be cut from a bar or sheet along the grain direction, have th
24、e following dimensions: be machined along the grain direction to a surface roughness Ra k 1,6 4m, then submitted to a stress relief of at least2h at150 C without decarburization. 4 Procedure Each bending angle (! o , ! f1 , if specified, and ! f2 ) is determined successively on the same test specime
25、n (seeFigure 2 to Figure 4). At least three test specimens shall be used. The test specimens shall be in the same condition as the parts they represent. NOTE 1Test specimens, possibly of a different steel grade, with a higher strength than the pieces may be used. NOTE 2The fracture angle of the test
26、 specimens per bending shall not exceed the deflection angle of the movable chuck. The diameter of the bending block and the deflection rate of the movable chuck shall be determined according to the material and thickness of the test specimen. Place the test specimen in the test machine (see Figure
27、1). Bend the test specimen under the specified deflection rate of the movable chuck until the first crack occurs in the centre part of the test specimen and measure the bending angles (! o , ! f1 , if specified, and ! f2 . Angle ! f1shall be measured within max.1h after surface treatment. 5 Expressi
28、on of results 6 Fault sanction The value of final ductility shall be specified in the process standard. w length: 180 mm to 200 mm w width: 15 mm to 20 mm w thickness: 1,8 mm to 4 mm w straightness deflection over the length: 0,25 mm, ductility after surface treatment: ! f1 /! o 100, in % final duct
29、ility: !; f2 /! o 100, in %EN 2831:1993 4 BSI 09-1999 7 Test report It shall include the following: reference to this standard; reference numbers of the test specimens; nature of the coating; thickness of the coating; diameter of the bending block and deflection rate of the movable chuck; values of
30、bending angles measured; test result. Figure 1 Placing of the test specimen before testing Figure 2 Bending angle prior to chemical or electrolytic treatmentEN 2831:1993 BSI 09-1999 5 Figure 3 Bending angle after surface treatment Figure 4 Bending angle after de-embrittlement6 blankBSEN 2831:1993 BS
31、I 09-1999 National annex NA (informative) Committees responsible The United Kingdom participation in the preparation of this European Standard was entrusted by the Aerospace Standards Policy Committee (ACE/-) to Technical Committee ACE/44 upon which the following bodies were represented: Aluminium F
32、inishing Association Metal Finishing Association Ministry of Defence National Centre of Tribology Oil and Colour Chemists Association Paintmakers Association of Great Britain Ltd. Society of British Aerospace Companies LimitedBS EN 2831:1993 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandar
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