ASD-STAN PREN 4827-2018 Aerospace series Hexavalent chromium free anodizing of aluminium and aluminium alloys (Edition P 2).pdf

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1、ASD-STAN STANDARD NORME ASD-STAN ASD-STAN NORM ASD-STAN prEN 4827 Edition P 2 June 2018 PUBLISHED BY THE AEROSPACE AND DEFENCE INDUSTRIES ASSOCIATION OF EUROPE - STANDARDIZATION Rue Montoyer 10 - 1000 Brussels - Tel. + 32 2 775 8126 - Fax. + 32 2 775 8131 - www.asd-stan.org ICS: Supersedes edition P

2、 1 of January 2015 and will supersede EN 4827:2017 Descriptors: ENGLISH VERSION Aerospace series Hexavalent chromium free anodizing of aluminium and aluminium alloys Luft- und Raumfahrt Anodisieren von Aluminium und Aluminiumlegierungen ohne hexavalentem Chrom Srie arospatiale Anodisation sans chrom

3、e hexavalent de laluminium et des alliages daluminium This “Aerospace Series“ Prestandard has been drawn up under the responsibility of ASD-STAN (The AeroSpace and Defence Industries Association of Europe - Standardization). It is published for the needs of the European Aerospace Industry. It has be

4、en technically approved by the experts of the concerned Domain following member comments. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or functionally, without re-identification of the stand

5、ard. After examination and review by users and formal agreement of ASD-STAN, the ASD-STAN prEN will be submitted as a draft European Standard (prEN) to CEN (European Committee for Standardization) for formal vote and transformation to full European Standard (EN). The CEN national members have then t

6、o implement the EN at national level by giving the EN the status of a national standard and by withdrawing any national standards conflicting with the EN. ASD-STAN Technical Committee approves that: “This document is published by ASD-STAN for the needs of the European Aerospace Industry. The use of

7、this standard is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” ASD-STAN reviews each standard and technical report at least every five years at which time it may be revis

8、ed, reaffirmed, stabilized or cancelled. ASD-STAN invites you to send your written comments or any suggestions that may arise. All rights reserved. No parts of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photoc

9、opying, recording, or otherwise, without prior written permission of ASD-STAN. Order details: E-mail: salesasd-stan.org Web address: http:/www.asd-stan.org/ Edition approved for publication 1st June 2018 Comments should be sent within six months after the date of publication to ASD-STAN Material Dom

10、ain Copyright 2018 ASD-STAN prEN 4827:2018 (E) 2 Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Terms and definitions . 4 4 General principles of the process 5 5 Process requirements . 7 6 Engineering requirements 10 7 Quality requirements 12 Annex A (normative) Engineering requiremen

11、ts . 14 Annex B (normative) Quality requirements . 15 B.1 Quality requirements 15 B.2 Dye-spot test . 16 Annex C (informative) Standard evolution form 19 Foreword This standard was reviewed by the Domain Technical Coordinator of ASD-STANs Material Domain. After inquiries and votes carried out in acc

12、ordance with the rules of ASD-STAN defined in ASD-STANs General Process Manual, this standard has received approval for Publication. prEN 4827:2018 (E) 3 1 Scope This standard defines the requirements for hexavalent chromium free anodizing of aluminium and aluminium alloys for corrosion protection,

13、bonding and painting. Hard anodizing and plasma electrolytic anodizing (micro-arc oxidation) are not covered by this European Standard. The purpose of this standard is to give design, quality and manufacturing requirements. It does not give complete in-house process instructions; these are given in

14、the processors detailed process instructions. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest

15、 edition of the referenced document (including any amendments) applies. EN 2284, Aerospace series Sulphuric acid anodizing of aluminium and wrought aluminium alloys EN 3665, Aerospace series Test methods for paints and varnishes Filiform corrosion resistance test on aluminium alloys EN 4704, Aerospa

16、ce series Tartaric-Sulphuric-Acid anodizing of aluminium and aluminium wrought alloys for corrosion protection and paint pre-treatment (TSA) EN 4707, Aerospace series Acid pickling of aluminium and aluminium alloy without hexavalent chromium EN 6072, Aerospace series Metallic materials Test methods

17、Constant amplitude fatigue testing 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-condu

18、ctive coatings on non-magnetic electrically conductive basis materials Measurement of coating thickness Amplitude-sensitive eddy-current method (ISO 2360) EN ISO 2409, Paints and varnishes Cross-cut test (ISO 2409) EN ISO 9220, Metallic coatings Measurement of coating thickness Scanning electron mic

19、roscope method (ISO 9220) EN ISO 9227, Corrosion tests in artificial atmospheres Salt spray tests (ISO 9227) EN ISO 10289, Methods for corrosion testing of metallic and other inorganic coatings on metallic substrates Rating of test specimens and manufactured articles subjected to corrosion tests (IS

20、O 10289) prEN 4827:2018 (E) 4 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: x IEC Electropedia: available at http:/www.electropedia.org/ x ISO

21、Online browsing platform: available at http:/www.iso.org/obp 3.1 General terms 3.1.1 OEM producer who manufactures products or components that are purchased by a company and retailed under that purchasing companys brand name Note 1 to entry: The OEM can also apply the process. 3.1.2 manufacturer com

22、pany or person who makes, fabricates, assembles components Note 1 to entry: The manufacturer can also apply the process. 3.1.3 processor company or person who applies the process 3.1.4 process instruction document that describes the application scopes, detailed process (key parameters, detailed step

23、s, etc.), quality management, environmental and safety regulations, etc. 3.1.5 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 3.2 Technical terms 3.2.1 de-anodizing process, which removes the anodic oxid

24、e 3.2.2 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 3.2.3 Mechanically Disturbed Layer MDL layer that is present at the surface resulting from the rolling process of the material prEN 4827:2018 (E) 5

25、 3.2.4 pit surface corrosion defect at which the anodic coating is penetrated and/or perforated Note 1 to entry: Typical characteristics of corrosion pits are: x rounded or irregular or elongated geometry, x tail or line or halo that emerges from the cavity, x some corrosion by-products inside pits

26、(on aluminium 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 shall exhibit at least two of the above characteristics. 3.2.5 re-anodizing repetition of the anodizing process step after complete de-anodizi

27、ng 3.2.6 sealing chromate VI 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 without additives at different temperatures. Sealing improves the corrosion resistan

28、ce performance of the anodic film. 4 General principles of the process 4.1 Purpose of the process The anodizing is an electrochemical process voltage controlled allowing transforming the aluminium (and its alloys) surface in a nanoporous and amorphous oxide layer made of a structure close to alumina

29、. 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. Anodizing is generally sealed for corrosion protection application (with or without painting or bonding) and can remain unsealed when the part is bond

30、ed or painted. This specification is applicable on aluminium and aluminium alloys generally on single parts. Hard anodizing and plasma electrolytic anodizing (micro-arc oxidation) dedicated to wear protection are not covered by this specification. 4.2 Applicability 4.2.1 Type A: unsealed anodizing I

31、t shall be used either as surface preparation before the application of painting/bonding or any other finishing. prEN 4827:2018 (E) 6 4.2.2 Type B: sealed anodizing It is intended for corrosion protection. It shall be with or without dyeing and used with or without additional painting. Table 1 Diffe

32、rent application cases Unsealed (type A) Sealed (type B) Unpainted Painted Bonding (structural) Unpainted Painted Sulphuric acid anodizing (SAA) EN 2284 Not applicable Applicable Not applicable Applicable Applicable Thin film sulphuric acid anodizing (TFSAA) Tartaric sulphuric acid anodizing (TSA) E

33、N 4704 Not defined yet with chromate VI free sealing Boric sulphuric acid anodizing (BSAA) Not applicable Phosphoric acid anodizing (PAA) Applicable Not applicable Sulphuric phosphoric acid anodizing (PSA) 4.3 Limitations All processes that can compromise the anodic film such as forming, or heat-tre

34、atment shall be performed prior to surface preparation of the parts to be anodized. Anodizing shall not be applied: x in electric conductivity zones/areas; x for tubes, pipes and open holes with a length to diameter ratio higher than 10:1 (unless using specific cathode); x for trapped holes with a l

35、ength to a diameter ratio greater than 5:1; x for parts or assemblies (e.g. spot-welded and riveted), which can permanently entrap treatment solutions; x for components which can permanently entrap treatment solutions, except components that can be adequately masked. NOTE The formation of oxide laye

36、r influences the dimensions of the part and is to be considered for close tolerance parts. prEN 4827:2018 (E) 7 4.4 Protection system classification 4.4.1 System types Anodizing layer is classified by the two following types: x type A: unsealed anodizing: It shall be used as surface preparation befo

37、re the application of painting/ bonding or any other finish; x type B: sealed anodizing: It is intended for corrosion protection. It shall be with or without dyeing and used with or without additional painting. 4.4.2 Layer thickness See Table 2. Table 2 Layer thicknesses corresponding to the class t

38、ype Class type Typical thickness Anodizing process Class 1 1 m Phosphoric acid anodizing (PAA) Sulphuric phosphoric acid anodizing (PSA) a Class 2 2 m to 8 m Tartaric sulphuric acid anodizing (TSA) Boric sulphuric acid anodizing (BSAA) Thin film sulphuric acid anodizing (TFSAA) Class 3 8 m to 25 m S

39、ulphuric acid anodizing (SAA) a 5 m for some aluminium alloys under agreement between the processor and the OEM/manufacturer. 5 Process requirements 5.1 Information for the processor x type and class designation, x substrate standard reference and heat treatment, x areas to be anodized, x anodizing

40、thickness measuring points, x electrical contact points or areas where these are inadmissible, x specification for testing on parts and/or samples. 5.2 Condition of parts prior to the treatment Welding, soldering/brazing, mechanical operations and heat treatments shall have been completed. x the par

41、ts shall be free of oil, grease, marking inks and other surface contaminations; x the surface shall be free from precipitations or smut from alloying elements or pre-processes indicated by the bright and uniform appearance of the surface; prEN 4827:2018 (E) 8 x mechanically disturbed layer shall be

42、removed either by mechanical or chemical processes; x in case of re-anodizing all residuals from the previous anodizing shall be completely removed. 5.3 Process conditions 5.3.1 Tooling The tools, bars, electrical contact systems, and metal masking tooling shall be free of oxidation/corrosion or any

43、 other damage which may be detrimental to the treatment during use. The part racks and tools shall be designed and set up in such a manner as to: x avoid any retention of air or treatment solution in the parts, x facilitate neutralization and removal of solutions during rinsing operations, x the ele

44、ctrical contacts shall be kept in good condition for the correct passage of the current, x electrical contact points should be defined between the processor and the OEM/manufacturer, x the contact is preferably achieved at several points in order to ensure better current distribution, x avoid any ac

45、cidental contact between the parts to be treated and the tank equipment or electrodes, and between the different parts during all the process, x the fixturing tools (e.g. made of aluminium alloy or titanium) shall provide effective electrical contact with the parts. 5.3.2 Masking The parts shall be

46、at least degreased prior to masking. Component areas which shall not be coated shall be masked with suitable material. 5.3.3 Surface pre-treatment Surface preparation means any method able to eliminate completely all surface contaminations. In case of chemical pre-treatment, the final step prior to

47、anodizing shall be acidic pickling, preferably chromate-free. Anodizing shall be performed immediately after pickling (in accordance with aluminium and aluminium alloys pickling standard EN 4707). 5.3.4 Anodizing During the anodizing process: x distance between electrode and parts and between parts

48、shall be adopted to avoid damage of parts by short-circuits and electric arc discharge ; x parts should be fully immersed; x the parts shall not be subjected to any tensile, flexure, torsion or other stress; prEN 4827:2018 (E) 9 x the process shall be performed in such a way that parts remain wet be

49、tween each step of the process; x the anodizing parameters (temperature, voltage, time) shall be adapted to the material and to the chemical composition of the bath; x in case of re-anodizing, the former protection will have to be totally removed before (chemically or mechanically) (see 5.5). 5.3.5 Anodizing post-treatments After the anodizing procedure: x parts have to be adequately rinsed with water according to 5