1、STD-AECMA PREN 4474-ENGL L979 M LOL23LL 00Lb050 LT2 H C3 Chairman Comments should be sent within six months ailer the date of publication to AECMA STANDARD NORME AECMA AECMA NORM I prEN 4474 Edition P I February 1999 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94
2、 - 6-1200 BRUXELLES - Tel. (+32) 2 775 81 10 - Fax. (+32) 2 775 81 11 ICs: 49.040 Descriptors: ENGLISH VERSION Aerospace series Aluminium pigmented coatings Coating methods Srie arospatiale Revtements alumino-organiques Mthodes dapplication Luft- und Raumfahrt Aluminium pigmenttete Beschichtungen Be
3、schichtungsverfahren This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA (The European Association of Aerospace Industries). It is published on green paper for the needs of AECMA-Members. It has been technically approved by the experts of the concerned Technical C
4、ommittee following comment by the Member countries. Subsequent to fhe 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 standard. Affer examination and signature o
5、f the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Member countries it will be submitted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. Nota - Extra copies can be SUDDkd by B.N.A.E. - Technopolis 54 - 199, ru
6、e JeanJacques Rousseau - 92138 ISSY-LES-MOULINEAUX CEDEX Edition approved for publication 1999-02-26 AECMA Gulledelle 94 8-1200 BRUXELLES Mr Visconti I l aecma 1999 Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo repr
7、oduction or networking permitted without license from IHS-,-,-STD*AECMA PREN 4474-ENGL L999 I LO123LL 00Lb05L 037 Page 3 prEN 4474: 1999 I Scope This standard defines the coating methods and characteristics of aluminium pigmented coatings to EN 4473 which may be applied to fasteners in titanium, tit
8、anium alloys, heat resisting nickel base or cobalt base alloys and corrosion resisting steels excluding high strength steels above 1 550 MPa. 2 Purpose of process To reduce galvanic corrosion, wear, risk of seizing and, in some cases, fretting corrosion 3 Normative references IS0 1463 IS0 2409 IS0 2
9、431 IS0 2859-1 IS0 2884 IS0 8080 EN 2000 EN 2516 EN 3032 EN 4473 Metallic and oxide coatings - Measurement of coating thickness - Microscopical method Paints and varnishes - Cross cut test Paints and varnishes - Determination of flow time by use of flow cups Sampling procedures for inspection by att
10、ributes - Part 1: Sampling plans indexed by acceptable quality level (AQL) for lot-by-lot inspection Paints and varnishes - Determination of viscosity at a high rate of shear Aerospace - Anodic treatment of titanium and titanium alloys - Sulphuric acid process Aerospace series - Quality assurance -
11、EN Aerospace products - Approval of the quality system of manufacturers Aerospace series - Passivating of corrosion resisting steels and decontamination of nickel base alloys Aerospace series -Test method for dry film lubricants - Thickness measurement Aerospace series - Aluminium pigmented coatings
12、 - Technical specification 1) 4 Terms and definitions For the purposes of this standard, the following terms and definitions apply. 4. I batch parts subjected to the same aluminium pigmented coating application at the same time under the same condition 1) Published as AECMA Prestandard at the date o
13、f publication of this standard Previous page is blank Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STD*AECMA PREN 4474-ENGL 1999 101i23LL 001b052 T7
14、5 II Page 4 prEN 4474: 1999 4.2 pre-p rod u c t i on parts parts representing future production parts 4.3 defini tion doc urne nt document specifying directly or indirectly all the requirements for the parts 4.4 scratch gouged out or scoring of metallic coating 4.5 run localized excess amount of coa
15、ting to the extent of creating a drip or running of coating 4.6 indentation indent or uneven surface thickness (orange peel) 4.7 flaking particles of coating falling off due to poor adhesion or excess coating 4.8 crack separation of coating de to improper mix or poor adhesion of material 4.9 samplin
16、g plan plan according to which one or more samples are taken in order to obtain information and to reach a decision, if possibly 4.10 acceptable quality level AQL maximum percent defective (or the maximum number of defects per hundred units) that, for purposes of sampling inspection, can be consider
17、ed satisfactory as a process average NOTE probability of acceptance Variant: quality level which in a sampling plan corresponds to a specified but relatively high 5 Apparatus 5.1 For application by dipping Container with a lid, stirring device and temperature control The apparatus shall be capable o
18、f applying the specified thickness, for example by controlling the speed of immersion and removal and by draining or centrifuging the parts. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking p
19、ermitted without license from IHS-,-,-STD.AECMA PREN 4474-ENGL 1999 m 101231L 00Lb053 901 Page 5 prEN 4474: 1999 5.2 For application by spraying A dry, oil free air fed gun shall be used, with settings adapted to the characteristics of the aluminium pigmented coating used and to the shape of the par
20、ts to be coated. Preferably a mechanical stirring device in the reservoir NOTE 1 will give a more uniform application. NOTE 2 A device allowing for rotation of the parts to be coated and the automatic displacement of the gun Use of an aerosol spray is not suitable as it does not always ensure accept
21、able reproducibility. 5.3 For curing An oven capable of curing temperatures prescribed by the coating manufacturer and controlled by periodical calibration 6 Information for the processor The following information is to be given: - designation of the aluminium pigmented coating to EN 4473; - percent
22、age of solvent plus reference of the solvent product; - number of the material standard and metallurgical condition of the latter; - areas to be processed; - thickness of the pigmented coating, if necessary, (see table 1); - duration and temperature of curing. 7 Surface roughness of parts prior to a
23、pplication It shall be specified on the drawing or in the definition documents. NOTE service. The surface roughness is an important factor affecting adhesion and behaviour of the coating in 8 Surface preparation 8.1 Unless otherwise specified, anodize to IS0 8080 or degreasing followed by abrasive b
24、lasting. Parts in titanium and titanium alloys 8.2 Parts in corrosion resisting steel Unless otherwise specified, passivate to EN 2516 Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitt
25、ed without license from IHS-,-,-STD-AECMA PREN 4474-ENGL 1999 9 1012311 0016054 848 9 Page 6 prEN 4474: 1999 9 Coating It shall be performed: - within 24 h, after surface preparation; precautions shall be taken to prevent contamination or corrosion of the parts awaiting treatment; - in a clean and d
26、ry environment, relative humidity between 40 % and 75 %, temperature (20 k 5) “C avoiding any operations liable to contaminate the surfaces to be treated. 9.1 Application by dipping Dipping can be performed as follows: - adjust the viscosity of the solution (see IS0 2431 or IS0 2884) to the value gi
27、ven by the manufacturer of the product to be deposited; - if necessary, pre-heat the parts to about 50 OC; - immerse the parts at a speed determined by tests on pre-production parts; - keep the parts immersed for 2 s to 10 s; - remove the parts at a speed determined by tests on pre-production parts;
28、 - drain parts; - dry parts avoiding handling them; - if necessary, cure the coating in an oven. The temperature and duration shall comply with the values given by the manufacturer of the product used. 9.2 Application by spraying Spaying can be performed as follows: - adjust the viscosity of the sol
29、ution (see IS0 2431 or IS0 2884) to the value given by the manufacturer; - if necessary, pre-heat the parts to approx. 50 “C; - produce the coating by applying successive passes, the gun setting and its distance being determined by tests on pre-production parts; - dry parts avoiding handling them; -
30、 if necessary, cure the coating in an oven. The temperature and duration shall comply with the values given by the manufacturer of the product to be used. 9.3 Other applications Other application methods producing the same quality of deposit may be used (for example: barrel deposition). IO Post-trea
31、tment If the tolerances of the parts necessitate mechanical finishing, it shall be performed by honing, burnishing, barrel finishing or manual brushing according to the size of parts or the batch size. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under li
32、cense with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-STD.AECMA PREN 4474-ENGL 1999 m 3032332 003b055 784 Page 7 prEN 4474: 1999 11 Removal of the coating The following processes are generally used separately or as a combination: - removal by dry or wet a
33、brasive blasting with appropriate media; - chemical removal (by pickling or solvents) using products well known for being compatible with the basic metal. Following removal of the coating, the parts shall be subjected to a visual and dimensional inspection. I2 Characteristics, requirements and test
34、methods See table 1 Table 1 iu bclause 12.1 12.2 12.3 12.4 Characteristic Appearance Thickness Adhesion Curing verification Requirement a Uniform colour, a variation of this indicates incorrect distribution of the fillers in the coating. Absence of defects such as: scratches, pits, blisters, runs, i
35、ndentations, foreign bodies, accumulation of particles, lack of uniformity or any other surface imperfection Unless otherwise specified: 5 pm to 13 pm No flaking, blisters, cracks: IS0 2409, class 1 or less The coating shall not be damaged by a brief contact with a solvent. There shall be no evidenc
36、e of deposit on the pad. Inspection and test method Visual inspection Suitable method Qualification: IS0 1463 Acceptance: EN 3032 or with the purchasers agreement, a method based on measurement of the mass of the dry coating deposited In the case of dispute, IS0 1463 shall be applied. IS0 2409 Move
37、three times back and forward with a pad of cotton-wool impregnated with a solvent (for example methyl-ethyl-ketone). a On parts, if not possible, on accompanying test pieces Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for Resa
38、leNo reproduction or networking permitted without license from IHS-,-,-STD.AECMA PREN 4474-ENGL 1999 LO12311 0016056 b10 m Page 8 prEN 4474: 1999 13 Quality assurance 13.1 Approval of the processor EN 2000 13.2 Process approval Before beginning production, the processor shall apply the coating on pr
39、e-production parts and/or test pieces as agreed between the purchaser and processor. All the tests required by this standard (see clause 12) shall be carried out on these coated pre-production parts and/or test pieces, unless otherwise agreed between the purchaser and processor. If the test results
40、are satisfactory for the purchaser, he shall give his written approval to commence production. The process schedule shall not be changed thereafter without the prior agreement of the purchaser. 14 Acceptance 14.1 Appearance and thickness See table 1. Unless otherwise specified, sampling in accordanc
41、e with IS0 2859-1 : - sample size code letter, table 1, special inspection level S3; - simple sampling plan for normal inspection; - acceptance quality level (AQL) 15 14.2 Adhesion See table 1. The inspection level, the sampling plan and the acceptance quality level according to IS0 2859-1 shall be
42、defined by the purchaser. 14.3 Curing verification See table 1. The inspection level, the sampling plan and the acceptance quality level according to IS0 2859-1 shall be defined by the purchaser. 15 Re-coating After agreement of the user, the coated parts not meeting the requirements may be reproces
43、sed. The coating not meeting the requirements shall be removed by the appropriate methods maintaining the diameter toleranced before protection (see clause 11). Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
