1、BS EN 4827:2017Aerospace series Hexavalentchromium free anodizing ofaluminium and aluminiumalloysBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS EN 4827:2017 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 4827:2017. The UK pa
2、rticipation in its preparation was entrusted to TechnicalCommittee ACE/65, Non-metallic materials for aerospace purposes. 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 c
3、ontract. Users are responsible for its correct application. The British Standards Institution 2017.Published by BSI Standards Limited 2017ISBN 978 0 580 94828 2 ICS 49.025.20; 49.040 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published
4、under the authority of the Standards Policy and Strategy Committee on 28 February 2017.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS EN 4827:2017EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 4827 February 2017 ICS 49.025.20; 49.040 English Version Aerospace seri
5、es - Hexavalent chromium free anodizing of aluminium and aluminium alloys Srie arospatiale - Anodisation sans chrome hexavalent de laluminium et des alliages daluminiumLuft- und Raumfahrt - Hexavalentes chromfreies Anodisieren von Aluminium und Aluminiumlegierungen This European Standard was approve
6、d by CEN on 24 September 2016. 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-date lists and bibliographical references concerning such national
7、 standards may be obtained on application to the CEN-CENELEC 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 translation under the responsibility of a CEN member into its own language
8、and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hun
9、gary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG
10、 CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2017 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 4827:2017 EBS EN 4827:2017EN 4827:2017 (E) 2 Contents Page European foreword 3 1 Scope 4 2 Normative references
11、4 3 Purpose of process . 5 4 Terms and definitions . 6 5 Protection system classification 7 6 Process requirements . 8 7 Engineering requirements 10 8 Quality requirements 12 Annex A (normative) Engineering requirements . 14 Annex B (normative) Quality requirements . 15 B.1 Quality requirements 15 B
12、.2 Interpretation of the results of the dye-spot test 15 Bibliography 18 BS EN 4827:2017EN 4827:2017 (E) 3 European foreword This document (EN 4827:2017) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-STAN). After enquiries and votes carried ou
13、t in 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 publ
14、ication of an identical text or by endorsement, at the latest by August 2017, and conflicting national standards shall be withdrawn at the latest by August 2017. 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 s
15、hall 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, Croatia, Cyprus, Czech Republic, D
16、enmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS
17、EN 4827:2017EN 4827:2017 (E) 4 1 Scope This European Standard defines the requirements for hexavalent chromium free anodizing of aluminium and aluminium alloys for corrosion protection, bonding and painting. Hard anodizing is not covered by this European Standard. The purpose of this European Standa
18、rd is to give design, quality and manufacturing requirements. It does not give complete in-house process instructions; these shall be given in the manufacturers detailed process instructions. 2 Normative references The following documents, in whole or in part, are normatively referenced in this docu
19、ment and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 2284, Aerospace series Sulphuric acid anodizing of aluminium and wrought aluminium alloys
20、 EN 3665, Aerospace series Test methods for paints and varnishes Filiform corrosion resistance test on aluminium alloys EN 4704, Aerospace series Tartaric-Sulphuric-Acid anodizing of aluminium and aluminium wrought alloys for corrosion protection and paint pre-treatment (TSA) EN 4707, Aerospace seri
21、es Acid pickling of aluminium and aluminium alloy without hexavalent chromium EN 6072, Aerospace series Metallic materials Test methods Constant amplitude fatigue testing EN ISO 2409, Paints and varnishes Cross-cut test (ISO 2409) EN ISO 9227, Corrosion tests in artificial atmospheres Salt spray tes
22、ts (ISO 9227) EN ISO 1463, Metallic and oxide coatings Measurement of coating thickness Microscopical method (ISO 1463) EN ISO 2085, Anodizing of aluminium and its alloys Check for continuity of thin anodic oxidation coatings Copper sulfate test (ISO 2085) EN ISO 2360, Non-conductive coatings on non
23、-magnetic electrically conductive basis materials Measurement of coating thickness Amplitude-sensitive eddy-current method (ISO 2360) EN ISO 9220, Metallic coatings Measurement of coating thickness Scanning electron microscope method (ISO 9220) BS EN 4827:2017EN 4827:2017 (E) 5 3 Purpose of process
24、The anodizing is an electrochemical process voltage controlled allowing transforming the metal surface in a microporous oxide layer made of alumina. The aim of this treatment is to ensure a protection against the corrosion, and/or to be used as an adhesion base before bonding or before painting. Thi
25、s anodizing is generally sealed for protection corrosion application (with or without painting or bonding) and can stay unsealed when the part is bonded or painted. This specification is applicable on aluminium and aluminium alloys generally on single parts. Hard anodizing and plasma electrolytic an
26、odizing dedicated to wear protection are not covered by this specification. 3.1 Applicability 3.1.1 Type A: unsealed anodizing It shall be used either as surface preparation before the application of painting/bonding or any other finishing. 3.1.2 Type B: sealed anodizing It is intended for corrosion
27、 protection. It shall be with or without dyeing and used with or without additional painting. See Table 1. Table 1 Different application cases Unsealed (type A) Sealed (type B) Unpainted Painted Bonding (structural) Unpainted Painted Sulfuric acid anodizing (SAA) EN 2284 Not applicable Applicable No
28、t applicable Applicable Applicable Thin film sulfuric acid anodizing (TFSAA) Tartaric sulfuric acid anodizing (TSA) EN 4704 Not defined yet with chromate free sealing Boric sulfuric acid anodizing (BSAA) Not applicable Phosphoric acid anodizing (PAA) Applicable Not applicable Sulfuric phosphoric aci
29、d anodizing (PSA) BS EN 4827:2017EN 4827:2017 (E) 6 3.2 Limitations All processes that can compromise the anodic film such as forming, or heat-treatment shall be performed prior to surface preparation of the parts to be anodized. Anodizing shall not be applied: in electric conductivity zones/areas;
30、for tubes, pipes and open holes with a length to diameter ratio higher than 10:1 (unless using specific cathode); for trapped holes with a length to a diameter ratio greater than 5:1; for parts or assemblies (e.g. spot-welded and riveted), which can permanently entrap treatment solutions; for compon
31、ents which can permanently entrap treatment solutions, except components that can be adequately masked. NOTE The formation of oxide layer influences the dimensions of the part and is to be considered for close tolerance parts. 4 Terms and definitions For the purposes of this document, the following
32、terms and definitions apply. 4.1 de-anodizing process, which removes the anodic oxide 4.2 smut precipitations of alloying elements (e.g. Cu, Fe, Zn, Si) on the surface of parts after a process step normally after alkaline etching step 4.3 Mechanically Disturbed Layer MDL layer that is present at the
33、 surface resulting from the rolling process of the material 4.4 pit surface corrosion defect at which the anodic coating is penetrated Note 1 to entry: Typical characteristics of corrosion pits are: rounded or irregular or elongated geometry, comet tail or line or halo that emerges from the cavity,
34、some corrosion by-products inside pits (on aluminium specimens the by-product may be granular, powdery or amorphous and white, grey or black in colour). To be considered as a corrosion pit, a surface cavity must exhibit at least two of the above characteristics. BS EN 4827:2017EN 4827:2017 (E) 7 4.5
35、 process instruction document that describes the application scopes, detailed process (key parameters, detailed steps, etc.), quality management, environmental and safety regulations, etc. 4.6 alloys all aluminium alloys, that are treated with the chromate free anodizing process in the specific shop
36、 4.7 re-anodizing repetition of the anodizing process step after complete de-anodizing 4.8 sealing chromate free sealing (of the anodized layers) is applied to close the pores produced by the acid anodizing process. Note 1 to entry: It is usually applied in hot demineralized water bath with or witho
37、ut additives at different temperatures. Sealing improves the corrosion resistance performance of the anodic film. 4.9. batch unless otherwise specified, it comprises parts of the same type (i.e. shape, size, material), processed at the same time in the same bath 5 Protection system classification 5.
38、1 System types Anodizing layer is classified by the two following types: Type A: unsealed anodizing: It shall be used as surface preparation before the application of painting/ bonding or any other finish. Type B: sealed anodizing: It is intended for corrosion protection. It shall be with or without
39、 dyeing and used with or without additional painting. 5.2 Layer thicknesses See Table 2. Table 2 Layer thicknesses corresponding to the class type Class type Typical thickness Anodizing process Class 1 1 m Phosphoric acid anodizing (PAA) Sulfuric phosphoric acid anodizing (PSA) a Class 2 2 m to 8 m
40、Tartaric sulfuric acid anodizing (TSA) Boric sulfuric acid anodizing (BSAA) Thin film sulfuric acid anodizing (TFSAA) Class 3 8 m to 25 m Sulfuric acid anodizing (SAA) a 5 m for some Aluminium alloys under agreement between purchaser and supplier. BS EN 4827:2017EN 4827:2017 (E) 8 6 Process requirem
41、ents 6.1 Information for the processor type and class designation, substrate standard reference and heat treatment, areas to be anodized, anodized thickness measuring points, electrical contact points or areas where these are inadmissible, specification for testing on parts and/or samples. 6.2 Condi
42、tion of parts prior to the treatment Welding, soldering/brazing, mechanical operations and heat treatments shall have been completed. the parts shall be free of oil, grease, marking inks and other surface contaminations; the surface shall be free from precipitations or smut from alloying elements or
43、 pre-processes indicated by the bright and uniform appearance of the surface; mechanically disturbed layer shall be removed either by mechanical or chemical processes; in case of re-anodizing all residuals from the previous anodizing shall be completely removed. 6.3 Process conditions 6.3.1 Tooling
44、The tools, bars, electrical contact systems, and metal masking tooling must be free of corrosion or any other damage which may be detrimental to the treatment during use. The part racks and tools must be designed and set up in such a manner as to: avoid any retention of air or treatment solution in
45、the parts, facilitate neutralization and removal of solutions during rinsing operations, the electrical contacts must be kept in good condition for the correct passage of the current avoid any accidental contact between the parts to be treated and the tank equipment or electrodes, and between the di
46、fferent parts during all the process. electrical contact points should be defined between purchaser and processor; the fixturing tools (e.g. in aluminium alloy or titanium) must provide effective electrical contact with the parts; the contact is preferably achieved at several points in order to ensu
47、re better current distribution. BS EN 4827:2017EN 4827:2017 (E) 9 6.3.2 Masking The parts shall be at least degreased prior to masking. Component areas which must not be coated shall be masked with suitable material. 6.3.3 Surface pre-treatment Surface preparation means any method able to eliminate
48、completely all surface contaminations. In case of chemical pre-treatment, the final step prior to anodizing shall be acidic pickling, preferably chromate-free. Anodizing must be performed immediately after pickling (in accordance with aluminium and aluminium alloys pickling standard EN 4707). 6.3.4
49、Anodizing During the anodizing process: distance between part and electrode must be defined to have the requested anodic layer thickness without electrical arc; parts should be fully immersed; the parts shall not be subjected to any tensile, flexure, torsion or other stress; the process shall be performed in such a way that parts do not dry between single process steps (pre-treatment, anodizing, etc.); the anodizing parameters (temperature, voltage, time) shall be
