1、AECMA STANDARD NORME AECMA AECMA NORM Edition approved for publication 1996-01-31 prEN 3769 Edition 1 January 1996 The equivalent versions in French and German languages can be supplied by B.N.A.E. - Technopolis 54 - 199, rue Jean-Jacques Rousseau 92138 ISSY - LES - MOULINEAUX CEDEX - FRANCE PUBLISH
2、ED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - 8-1200 BRUXELLES - Tel. (32) 2 775 81 10 - Fax. (32) 2 775 81 11 ICs : 49.040.40 ENGLISH VERSION Aerospace series Electrolytic polishing of corrosion resistant steels and heat resisting alloys Srie arospatiale Luft- und R
3、aumfahrt Polissage lectrolytique Elektrolytisches Polieren des aciers rsistant la corrosion et des alliages rsistant chaud von korrosionsbestndigen Sthlen und hochwarmfesten Legierungen This Aerospace series“ Standard has been drawn up under the responsibility of AECMA (The European Association of A
4、erospace Industries). It is published on yellow paper in three equivalent versions (English, French, German). It will be submitted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. STD*AECMA PREN 37b9-ENGL 377b O 3032333 O032777 702 O Page 3 prEN 3769 : 19
5、96 1 Scope This standard specifies the electrolytic polishing of corrosion resistant steels and heat resisting alloys used in aerospace constructions. It shall be applicable whenever referenced. 2 Purpose of process To improve the surface condition and/or increase the corrosion resistance by elimina
6、ting any metallic surface contamination. 3 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 refere
7、nces, subsequent 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 9227 Corrosion tests in artificial atmospheres - Salt
8、spray tests EN 2000 Aerospace series - Quality assurance - EN aerospace products - Approval of the quality system of manufacturers EN 251 6 Aerospace series - Passivation of corrosion resistant steels and decontamination of nickel base alloys 4 Definitions For the purposes of this standard, the foll
9、owing definitions apply. 4.1 material), treated at the same time in the same bath. Batch : Unless otherwise specified, it shall comprise parts of the same nature (form, size, 4.2 Pre-production parts : Parts representing future production. 5 Information for the processor - Designation, see 11 ; - nu
10、mber of the material standard and metallurgical conditon of the latter ; - areas to be processed ; - permitted electrical contact points or areas where these are prohibited. 1) Published as AECMA Standard at the date of publication of this standard STD-AECMA PREN 37b7-ENGL L77b W LOL23LL 0012778 bq7
11、 Page 4 prEN 3769 : 1996 6 Treatment The parts shall be : - degreased and deoxidized ; - treated in a solution. Examples of appropriate solutions are described in annex A ; - rinsed and dried. To improve corrosion resistance, a passivation in accordance with EN 2516 may be carried out. 7 Required ch
12、aracteristics 7.1 Appearance The surface shall be smooth and glossy, free from corrosion Pittings. 7.2 Surface cleanness and corrosion resistance The surface of the parts shall have no metallic contamination and no signs of corrosion even after 24 h of exposure to salt spray. 7.3 They shall be in ac
13、cordance with the indications in the design documents. Dimensions and surface roughness after processing 7.4 Intergranular corrosion The surface of the parts shall have no such corrosion. 8 Inspection and test methods 8.1 Approval of the process 8.1 .I Appearance Visual inspection 8.1.2 The salt spr
14、ay test shall be made in accordance with IS0 9227 in a 5 % solution of sodium chloride. Surface cleanness and corrosion resistance 8.1.3 They shall be verified by dimensional measurements carried out before and after processing. Dimensions and surface roughness after processing 8.1.4 Intergranular c
15、orrosion Metallographic examination shall be made on a cross-section at a magnification of min. 300 times. 8.2 Acceptance of parts 8.2.1 Appearance See 8.1 .I. I STD-AECMA PREN 37b7-ENGL L77b LOL23LL 0032799 585 Page 5 prEN 3769 : 1996 8.2.2 See 8.1.2. Surface cleanness and corrosion resistance 8.2.
16、3 Dimensional inspection See 8.1.3. 8.2.4 Intergranular corrosion See 8.1.4. 9 Quality assurance 9.1 Approval of the processor See EN 2000. 9.2 Process approval The processor shall carry out : - electrolytic polishing on pre-production parts and/or test pieces, determined by agreement between the pu
17、rchaser and processor ; - tests specified in this standard, unless otherwise agreed between the purchaser and processor. Other specific tests may be carried out at the purchasers request, for example creep, impact strength, etc When the test results have been accepted as satisfactory by the purchase
18、r, he shall give his written approval to start production. The procedure shall not be changed without previous agreement from the purchaser. 9.3 Acceptance The frequency and nature of the inspection of parts and test pieces shall be defined in the design documents or determined by agreement between
19、the purchaser and processor. The appearance inspection (see 8.2.1) shall be carried out on the whole batch unless otherwise specified. By no means it shall be less than 10 % of the batch with a minimum of 20 parts. In case of accompanying test pieces, the metallographic examination (see 8.2.4) shall
20、 be carried out at a rate of one test per batch. The frequency of the other tests (see 8.2.2 and 8.2.3) shall be determined by agreement between the purchaser and processor. 9.4 Re-treatment It is permitted if the parts are not within the specified dimensions or if the surface roughness is not achie
21、ved. io The locally applicable regulations and laws shall be observed. Health, safety and environmental aspects 11 Designation EXAMPLE : Number of this standard ” STD-AECflA PREN 37bq-ENGL 177b = LO12311 O013001 831 Page 7 prEN 3769 : 1996 V A/dm2 Annex A (informative) Electrolytic polishing 15 to 3
22、0 12 to 30 11 to 15 100 to 200 20 to 40 60 to 75 Composition of the solution and use conditions Phosphoric acid (d = 1,701 Chromic acid anhydride I Suiphuric acid (d = 1,841 Operating temperature Voltage Current density I Units I no1 1 200I 100 260 f 30 Solution n02 I n03 130 I20 330 i 25 OC 70 to 90 60 to 75 35 to 40 The solutions shall be controlled to maintain product concentrations in the given range.
