SIST EN 4729:2017

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Luft- und Raumfahrt - Chrom-(III)-basierte chemische Konversionsüberzüge für Aluminium und AluminiumlegierungenSérie aérospatiale - Conversion chimique au chrome trivalent de l’aluminium et des alliages d’aluminiumAerospace series - Trivalent chromium based chemical conversion coatings for aluminium and aluminium alloys49.025.20AluminijAluminium25.220.99Druge obdelave in prevlekeOther treatments and coatingsICS:Ta slovenski standard je istoveten z:EN 4729:2017SIST EN 4729:2017en,fr,de01-november-2017SIST EN 4729:2017SLOVENSKI
STANDARD



SIST EN 4729:2017



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 4729
September
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t wä t t rä { { English Version
Aerospace series æ Trivalent chromium based chemical conversion coatings for aluminium and aluminium alloysSérie aérospatiale æ Conversion chimique au chrome trivalent de l 5aluminium et des alliages d 5aluminium Konversionsüberzüge für Aluminium und Aluminiumlegierungen This European Standard was approved by CEN on
s v May
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egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Serbiaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
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t r s y CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
v y t {ã t r s y ESIST EN 4729:2017



EN 4729:2017 (E) 2 Contents Page European foreword . 3 1 Scope . 4 2 Purpose of process . 4 3 Normative references . 4 4 Terms and definitions . 4 5 Applicability and limitations of the process . 5 6 Classification . 5 7 Requirements . 5 8 Main technical engineering requirements . 8 9 Quality requirements . 10 10 Quality assurance . 12 11 Health, safety and environmental aspects . 12 12 Designation . 13
SIST EN 4729:2017



EN 4729:2017 (E) 3 European foreword This document (EN 4729:2017) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-STAN). After enquiries 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 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 publication of an identical text or by endorsement, at the latest by March 2018, and conflicting national standards shall be withdrawn at the latest by March 2018. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN 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, Croatia, Cyprus, Czech Republic, Denmark, 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.
SIST EN 4729:2017



EN 4729:2017 (E) 4 1 Scope This European Standard specifies trivalent chromium based chemical conversion coatings for aluminium and aluminium alloys. It covers the application by bath but also by touch-up. It doesn’t give complete in-house process instructions; these shall be given in the manufacturers detailed process instructions. 2 Purpose of process The aim of the trivalent chromium based chemical conversion coatings is to increase corrosion resistance, to improve the adhesion of paints and varnishes and to ensure electrical conductivity. Coatings are also suitable for the repair of mechanically damaged anodic coatings. 3 Normative references The following documents, in whole or in part, are normatively referenced in this document 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 4707, Aerospace series — Acid pickling of aluminum and aluminum alloy without hexavalent chromium 1) EN 9100, Quality Management Systems — Requirements for Aviation, Space and Defence Organizations EN ISO 2409, Paints and varnishes — Cross-cut test EN ISO 2812-2, Paints and varnishes — Determination of resistance to liquids — Part 2: Water immersion method EN ISO 3892, Conversion coatings on metallic materials — Determination of coating mass per unit area — Gravimetric methods EN ISO 9227, Corrosion tests in artificial atmospheres — Salt spray tests 4 Terms and definitions For the purposes of this document, the following terms and definitions apply. 4.1 batch unless otherwise specified, it comprises parts of the same type (shape, size, material), processed at the same time in the same bath 4.2 substrate material upon which a coating is directly applied, in the case of a single or first coating, the substrate is the basis metal and for a subsequent coating, the intermediate coating is the substrate
1) Published as ASD-STAN Prestandard at the date of publication of this standard by AeroSpace and Defence industries Association of Europe - Standardization (ASD-STAN) (www.asd-stan.org) SIST EN 4729:2017



EN 4729:2017 (E) 5 4.3 pit substrate corrosion defect at which the conversion 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, • some corrosion by-products inside pits (on aluminium test samples the by-product may be granular, powdery or amorphous and white, grey or black in colour). Note 2 to entry: To be considered a corrosion pit, a surface cavity must exhibit at least two of the above characteristics. 5 Applicability and limitations of the process This standard applies whenever referenced. Parts with features that may trap treatment solutions shall be subjected to additional rinsing operations to ensure removal of treatment solutions. Chemical conversion treatment shall not be applied if removal of treatment solution cannot be assured. Chemical conversion coatings shall not be applied to parts before bonding or welding. The maximum in service temperature of the chemical conversion coatings, is 100 °C. 6 Classification 6.1 Coating weight For trivalent chromium base conversion coating, the mass per unit area should be ranged from 0,2 g/m2 to 0,9 g/m2. 6.2 Materials  Category 1: Aluminium alloy 1 000, 5 000 and 6 000 series,  Category 2: Aluminium alloy 2 000 and 7 000 series,  Category 3: Aluminium alloy castings. For cladded aluminium alloys, the clad is considered as the material. 7 Requirements 7.1 Process requirements 7.1.1 Information for the processor  categories of materials;  substrate standard reference and heat treatment;  areas to be coated;  specification for testing on parts and/or samples;  criticality of parts. SIST EN 4729:2017



EN 4729:2017 (E) 6 7.1.2 Condition of parts prior to processing  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;  mechanically disturbed layer shall be removed either by mechanical or chemical processes;  in case of re-treatment all residuals from the previous coating shall be completely removed. Tooling The tools and metal masking tooling must be protected against corrosion, and/or 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 the parts,  facilitate neutralization and removal of solutions during rinsing operations,  avoid during the treatment any accidental contact between the parts to be treated and the tank equipment, and between the different parts. The parts shall be previously degreased prior to masking. Component areas which must not be coated shall be masked with suitable material. 7.1.3 Pre-treatment The pre-treatment phase shall not result in critical deterioration of dimensions, surface finish and mechanical properties of parts. For conversion coating applied by touch up process or following vapor deposited aluminium (IVD or PVD)
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