1、AECMA STANDARD NORME AECMA AECMA NORM Edition approved for publication prEN 3837 Edition P 1 November 1996 Comments should be sent within six months C7 Chairman after the date of Dublication to PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - B-1200 BRUXELLES - T
2、el. (32) 2 775 81 10 - Fax. (32) 2 775 81 11 ICs : Descriptors : ENGLISH VERSION Aerospace series Paints and varnishes Nature and method for surface preparation of test pieces in aluminium alloys Srie arospatiale Peintures et vernis Nature et mthodes de prparation de surface des prouvettes en alliag
3、es daluminium Luft- und Raumfahrt Lacke und Anstrichstoffe Oberflchenvorbereitungstyp und methoden fr Proben aus Aluminiumlegierungen This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA (The European Association of Aerospace Industries). It is published on green p
4、aper for the needs of AECMA-Members. It has been technically approved by the experts of the concerned Technical Committee following comment by the Member countries. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is a
5、ffected, physically or functionally, without re-identification of the standard. After examination and signature of 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 Committ
6、ee for Standardization) for formal vote. 1996-1 1-29 AECMA Gulledelle 94 Mr Wrigth I 8-1 200 BRUXELLES I aecrna 1996 Page 3 prEN 3837 : 1996 1 Scope This standard defines the nature of and the surface preparation method for test pieces in aluminium alloys intended for testing paints and varnishes us
7、ed for aerospace applications. 2 Normative references This European Standard incorporates by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subs
8、equent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. IS0 3270 EN 2090 EN 2092 EN 2101 EN 2334 EN 2437 EN 2696 EN 2709 Pai
9、nts and varnishes and their raw materials - Temperatures and humidities for conditioning and testing Aerospace series - Aluminium alloy 2024-T3 - Clad sheet and strip - 0,4 5 a I6 mm 1) Aerospace series - Aluminium alloy AL-P7075- - T6 or T62 - Clad sheet and strip - 0,4 mm 5 a 56 mm Aerospace serie
10、s - Chromic acid anodizing of aluminium and wrought aluminium alloys Aerospace series - Chromic-sulphuric acid pickle of aluminium and aluminium alloys 1) Aerospace series - Chromate conversion coatings (yellow) for aluminium and aluminium alloys 2) Aerospace series - Aluminium alloy AL-P7075- - T6
11、or T62 - Sheet and strip - 0,4 mm I a I6 mm Aerospace series - Aluminium alloy 2024-T3510 - Bar and section - 1,2 I (a or D) I 150 mm - With peripheral coarse grain control 1) 3 Nature and size of test pieces Unless specifically defined, test pieces in aluminium alloys are described in table 1. Unle
12、ss otherwise specified in the test or product standard, the dimensions of the test pieces shall be : length : 125 mm width : 80 mm. 4 Method of preparing the surface Three processes surface treatments are applicable to aluminium alloys used in aeronautics : - process A: sulfochromic pickling in acco
13、rdance with EN 2334 : - process B: chromic acid anodizing, sealed or not, in accordance with EN 2101 ; - process C: chemical chromatation conversion in accordance with EN 2437. Each series gives the order and the nature of the different operations to be carried out (treatment, rinsing, stoving). Ann
14、exes A and B give the degreasing procedures before treatment. Process A is the “reference“ treatment. The choice of the treatment, processes B and/or C, is the result of an agreement between the interested parties or is imposed by the product specification. 1) Published as AECMA Standard at the date
15、 of publication of this standard 2) In preparation at the date of publication of this standard Page 4 prEN 3837 : 1996 5 Application of coating Coating shall be applied within 16 h after the end of the treatment and in conformity with the product specification and the suppliers instructions. After a
16、pplying the paint and prior to testing, the test pieces shall be kept in a room in conformity with IS0 3270 for the time specified in the material standard. Table : Synoptic table of test pieces I Nature I Page 5 prEN 3837 : 1996 6 The locally applicable regulations and laws shall be observed. Healt
17、h, safety and environmental aspects 7 Designation EXAMPLE : EN3837A IT Number of this standard I Process (see 4) 1012311 OOL3OLB 035 Page 6 prEN 3837 : 1996 Annex A (informative) SOLVENT DEGREASING This operation can be carried out : - in vapour phase ; - in liquid phase using a paint brush and a cl
18、oth that leaves no lint. Solvents used : - stabilized trichloroethylene (vapour phase) ; - standard quality perchlorothylene (vapour phase) ; - stabilized trichloroethane 1, 1, 1 (vapour or liquid phase) ; - other degreasing agent required by the customer. NOTE 1 : The possible ink markings on the s
19、urface of the sheets and extruded section shall be eliminated with denaturated alcohol. NOTE 2 : A regular film of water shall cover the pieces after rinsing, otherwise degreasing shall be repeated. .- LO12311 0013019 T7L Page 7 prEN 3837 : 1996 Annex B (informative) CHEMICAL DEGREASING Examples of
20、bath composition and treatment parameters Bath composition : - anhydrous sodium carbonate Nazco3 - anhydrous sodium phosphate Na3P04 - liquid silicate of sodium (r = 1,331 NapSiO3 - deionized water. Treatment parameters : - temperature - immersion time - air or mechanical stirring. : (40 I 1) g/l : (20 f 1) g/l : (1 f 0,l) g/l : (60 f 2) OC : (4f 1) min NOTE : A regular film of water shall cover the pieces after rinsing, otherwise degreasing shall be repeated.
