1、ASD-STAN STANDARD NORME ASD-STAN ASD-STAN NORM prEN 4474 Edition P 2 November 2014 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 1 of Feb
2、ruary 1999 and will supersede EN 4474:2009 Descriptors: ENGLISH VERSION Aerospace series Aluminium pigmented coatings Coating methods Srie arospatiale Revtements alumino-organiques Mthode dapplication Luft- und Raumfahrt Aluminium pigmenttete Beschichtungen Beschichtungsverfahren This “Aerospace Ser
3、ies“ 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 been technically approved by the experts of the concerned Domain following
4、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 standard. After examination and review by users and formal agreement of ASD-ST
5、AN, it 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 to implement the EN at national level by giving the EN the status of a national standard
6、and by withdrawing any national standards conflicting with the EN. Edition approved for publication 1st November 2014 Comments should be sent within six months after the date of publication to ASD-STAN Mechanical Domain percentage of solvent plus reference of the solvent product; number of the mater
7、ial 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 application It shall be specified on the drawing or in the definition documents. N
8、OTE The surface roughness is an important factor affecting adhesion and behaviour of the coating in service. 8 Surface preparation 8.1 Parts in titanium and titanium alloys Unless otherwise specified, degreasing followed by abrasive blasting. 8.2 Parts in corrosion resisting steel Unless otherwise s
9、pecified, or degreasing followed by abrasive blasting. 9 Coating 9.1 General It is recommended to apply the coating: if possible within 24 h, after surface preparation ; precautions shall be taken to prevent contamination or corrosion of the parts awaiting treatment; in a clean and dry environment,
10、avoiding any operations liable to contaminate the surfaces to be treated. 9.2 Application by dipping Dipping can be performed as follows: adjust the viscosity of the solution (see EN ISO 2431 or EN ISO 2884-1) to the value given by the manufacturer of the product to be deposited; if necessary, pre-h
11、eat the parts to about 50 C; immerse the parts at a speed determined by tests on pre-production parts; keep the parts immersed for 2 s to 10 s; prEN 4474:2014 (E) 6 remove the parts at a speed determined by tests on pre-production parts; drain parts; dry parts avoiding handling them; if necessary, c
12、ure the coating in an oven. The temperature and duration shall comply with the values given by the manufacturer of the product used. 9.3 Application by spraying Spaying can be performed as follows: adjust the viscosity of the solution (see ISO 2431 or ISO 2884-1) to the value given by the manufactur
13、er; 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; if necessary, cure the coating in an oven. The temperature and duration shall
14、 comply with the values given by the manufacturer of the product to be used. 9.4 Other applications Other application methods producing the same quality of deposit may be used (for example: barrel deposition). 10 Post-treatment If the tolerances of the parts necessitate mechanical finishing, it shal
15、l be performed by honing, burnishing, barrel finishing or manual brushing according to the size of parts or the batch size. 11 Removal of the coating The following processes are generally used separately or as a combination: removal by dry or wet abrasive blasting with appropriate media; chemical re
16、moval (by pickling or solvents) using products well known for being compatible with the base metal. Following removal of the coating, the parts shall be subjected to a visual and dimensional inspection. prEN 4474:2014 (E) 7 12 Characteristics, requirements and test methods See Table 1. Table 1 Subcl
17、ause Characteristic Requirement a Inspection and test method 12.1 Appearance Uniform colour, a variation of this indicates incorrect distribution of the fillers in the coating. Absence of defects such as: scratches, pits, blisters, runs, indentations, foreign bodies, accumulation of particles, lack
18、of uniformity or any other surface imperfection. Visual inspection 12.2 Thickness Unless otherwise specified: 5 m to 13 m on externally threaded fasteners; 5 m to 20 m on internally threaded fasteners. Suitable method Qualification: EN ISO 1463 Acceptance: EN 3032 or with the purchasers agreement, a
19、 method based on measurement of the mass of the dry coating deposited In the case of dispute, EN ISO 1463 shall be applied. 12.3 Adhesion No flaking, blisters, cracks: EN ISO 2409, class 1 or less EN ISO 2409 12.4 Curing verification The coating shall not be damaged by a brief contact with a solvent
20、. There shall be no evidence of deposit on the pad. Move 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. prEN 4474:2014 (E) 8 13 Quality assurance 13.1 Approval of the proce
21、ssor See EN 9100. 13.2 Process approval Before beginning production, the processor shall apply the coating on pre-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-produc
22、tion parts and/or test pieces, unless otherwise agreed between the purchaser and processor. If the test results 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 purch
23、aser. 14 Acceptance 14.1 Appearance and thickness See Table 1. Unless otherwise specified, sampling in accordance with ISO 2859-1: sample size code letter, Table 1, special inspection level S3; simple sampling plan for normal inspection; Acceptance Quality Limit (AQL) 1,5. 14.2 Adhesion See Table 1.
24、 The inspection level, the sampling plan and the acceptance quality level according to ISO 2859-1 shall be defined by the purchaser. 14.3 Curing verification See Table 1. The inspection level, the sampling plan and the acceptance quality level according to ISO 2859-1 shall be defined by the purchase
25、r. 15 Re-coating After agreement of the user, the coated parts not meeting the requirements may be reprocessed. The coating not meeting the requirements shall be removed by the appropriate methods maintaining the diameter tolerance before protection (see Clause 11). prEN 4474:2014 (E) 9 Annex A (inf
26、ormative) Standard evolution form The main changes with respect to the previous editions are listed in Table A.1. Table A.1 Main changes to previous editions prEN/EN Number Edition Publication Date Modification Reason and validation prEN 4474 P2 10/2014 8.1: removed anodization per ISO 8080 Poor adh
27、esion of aluminium pigmented coating on anodised titanium 9.1 a): “within 24 h after surface preparation” replaced by “if possible within 24 h after surface preparation” 24 h between surface preparation and coating application is recommended but not mandatory. If parts are stored in dry and clean en
28、vironment, this time can be longer without affecting coating quality. 9.1 b): removed requirements for humidity and temperature Humidity and temperature requirements of previous version are not achievable in regular application shop and are not influential parameters on coating application quality. 12.3: added 5 m to 20 m on internally threaded fasteners. In order to be consistent with EN 4473 related requirements
