SAE AMS 2470N-2013 Anodic Treatment of Aluminum Alloys Chromic Acid Process《铬酸法铝合金的阳极处理》.pdf

1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there

2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2013 SAE International All rights reserved. No part of this publication m

3、ay be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside U

4、SA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AMS2470N AEROSPACE MATERIAL SPECIFICATION AMS2470 REV. N Issued 1940-01 Revised 2013-07 Super

5、seding AMS2470M Anodic Treatment of Aluminum Alloys Chromic Acid Process RATIONALE This specification was issued as a result of the SAE Five Year Review process. ORDERING INFORMATION: The following information shall be provided to the processor by the purchaser. 1) Purchase order shall specify not l

6、ess than the following: AMS2470N Basis metal to be anodized Required color, if dyed Special features, geometry or processing present on parts that requires special attention by the processor Quantity of pieces to be anodized 2) Parts manufacturing operations such as heat treating, forming, joining a

7、nd media finishing can affect the condition of the substrate and adversely affect the finished part. The sequencing of these types of operations should be specified by the cognizant engineering organization or purchaser and is not controlled by this specification. 1. SCOPE 1.1 Purpose This specifica

8、tion establishes the requirements for anodic coatings on aluminum alloys. 1.2 Application This process has been used typically to increase corrosion resistance and to provide surfaces which will promote adherence of paint and other organic finishes, and has been found useful for assemblies which hav

9、e faying surfaces and/or which may trap electrolyte, but usage is not limited to such applications. 1.2.1 This process is primarily applicable to aluminum and aluminum alloy parts which have nominal copper content not greater than 5% by weight or total nominal alloy content not greater than 7.5% by

10、weight, AMS2471 being recommended for parts having higher alloy content. Coating may be dyed if specified, but AMS2472 is recommended where a colored finish is required. SAE AMS2470N Page 2 of 8 1.3 Safety - Hazardous Materials While the materials, methods, applications, and processes described or r

11、eferenced in this specification may involve the use of hazardous materials, this specification does not address the hazards which may be involved in such use. It is the sole responsibility of the user to ensure familiarity with the safe and proper use of any hazardous materials and to take necessary

12、 precautionary measure to ensure the health and safety of all personnel involved. 2. APPLICABLE DOCUMENTS The issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein. The supplier may work to a subsequent revision

13、 of a document unless a specific document issue is specified. When the referenced document has been cancelled and no superseding document has been specified, the last published issue of that document shall apply. 2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrenda

14、le, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AMS2471 Anodic Treatment of Aluminum Alloys, Sulfuric Acid Process, Undyed Coating AMS2472 Anodic Treatment of Aluminum Alloys, Sulfuric Acid Process, Dyed Coating AMS2473 Chemical Film Treatment

15、 for Aluminum Alloys, General Purpose Coating AMS4037 Aluminum Alloy, Sheet and Plate, 4.4Cu - 1.5Mg - 0.60Mn, (2024; -T3 Flat Sheet, -T351 Plate), Solution Heat Treated 2.2 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, T

16、el: 610-832-9585, www.astm.org. ASTM B 117 Operating Salt Spray (Fog) Testing Apparatus ASTM B 137 Measurement of Mass of Coating on Anodically Coated Aluminum ASTM D 1193 Reagent Water ASTM D 3762 Adhesive Bonded Surface Durability of Aluminum (Wedge Test) 3. TECHNICAL REQUIREMENTS 3.1 Solutions 3.

17、1.1 Electrolyte The electrolyte shall be an aqueous chromic acid solution. Use of surfactants and anti-misting additives shall be approved by the cognizant engineering organization before processing If surfactants have been approved for use and if anodized parts are to be subsequently adhesively bon

18、ded, purchaser shall notify processor of the need to perform the adhesive bond verification test of 3.4.3. 3.1.2 Dye, when used, shall be as required to produce the specified color. SAE AMS2470N Page 3 of 8 3.1.3 Sealer Unless otherwise permitted, the sealer shall be water of suitable purity and con

19、trolled pH maintained at a suitable temperature (See 8.2.10 through 8.2.12). 3.2 Preparation 3.2.1 Cleaning and Deoxidation Parts shall have clean surfaces, free from water break, prior to immersion in the anodizing bath. 3.2.1.1 Cleaning materials or products used for surface preparation containing

20、 iron, such as steel wool, iron oxide rouge, or steel wire, which may become embedded in the metal and accelerate subsequent corrosion, are prohibited. 3.2.2 Masking Areas where anodizing is prohibited shall be masked. 3.2.3 Tight electrical contact shall be maintained during the anodic treatment, t

21、o prevent contact arcing (burning) of parts, but small irregularities of coating at points of electrical contact are acceptable. For parts which are to be anodized all over, contact locations shall be acceptable to purchaser. For parts which are not to be anodized all over, locations shall be in are

22、as on which anodize is not required. 3.3 Procedure: 3.3.1 Anodizing The cleaned parts shall be made the anode(s) in the electrolyte contained in a suitable chemical-resistant tank which may also serve as the cathode. The processing shall be adjusted to obtain the required weight and quality of the c

23、oatings. The rate of increase of the voltage shall be maintained within a range of 2 V/min of the nominal value, and the anodizing voltage shall be maintained within 2 V of the nominal value. After anodizing, parts shall be rinsed thoroughly in water at ambient temperature and sealed (See 3.3.3) unl

24、ess dyeing (See 3.3.2) or other treatment is specified. 3.3.2 Dyeing Parts shall be dyed, when specified, to the color required by immersing in an appropriate dye solution. The anodic coating shall not be allowed to dry before dyeing. The temperature of the solution and the time of immersion shall b

25、e as necessary to produce the specified color. Either the parts or the solution shall be agitated during immersion. Parts shall then be rinsed in clean water at ambient temperature. 3.3.3 Sealing Parts shall be immersed in the sealant solution for a suitable time and temperature (See 8.2.11 and 8.2.

26、12), then rinsed. The rinse shall be thorough, but slight staining resulting from the sealant solution is acceptable. Rinsing is not required if reagent water (ASTM D 1193 Type IV) is used for sealing. 3.4 Properties Coated parts shall conform to the following requirements: SAE AMS2470N Page 4 of 8

27、3.4.1 Coating Weight The coating weight (See 4.3.2.1), determined in accordance with ASTM B 137, shall be not less than 200 milligrams/square foot (2 g/m2) on parts which are not to be dyed, and not less than 500 milligrams/square foot (5 g/m2) on parts which are to be dyed. 3.4.1.1 If small parts,

28、such as rivets or machine screws, are anodized in bulk in a container, the specified coating weight shall apply to not less than 75% of the parts treated together, determined by random sampling, but in no case shall any part show uncoated areas. 3.4.2 Corrosion Resistance Panels (See 4.3.2.2) shall

29、meet the following requirements, determined after exposure for not less than 336 hours to salt spray corrosion test in accordance with ASTM B 117, except that the significant surface shall be inclined 6 degrees from the vertical. The five test panels shall show not more than a total of 15 isolated c

30、orrosion pits, none larger than 1/32 inch (0.8mm) in diameter, in a total of 150 sq.inches (968 sq cm) of test area. Individual test panels shall show no more than 5 isolated corrosion pits, none larger than 1/32 inch (0.8mm) in diameter, in a total of 30 sq. inches (194 sq cm). (See 8.7 for definit

31、ion of corrosion pit morphology) Areas within 1/16 inch (1.6 mm) of identification markings or of an edge, or at electrode contact marks, shall not be included. 3.4.2.1 Panels which are acceptable to the criteria of 3.4.2 but which exhibit patchy dark gray areas (spots, streaks, or marks) with a whi

32、te chalky film on the surface shall be examined at 10X magnification. Pits, if discovered, shall be added to those found with the unaided eye and the acceptance criteria reapplied. 3.4.3 Adhesive Bond Verification Test When an anti-misting agent or surfactant is used as in 3.1.1, the effect of such

33、agents on adhesive bond strength shall be determined in accordance with ASTM D 3762, using panels primed and adhesively bonded with materials and procedures acceptable to purchaser. Test panels shall be conditioned by exposure to 100% RH at a temperature of 100 F 5 (49 C 3) for 60 minutes, minimum.

34、Crack growth in excess of 0.25 inch (6.4 mm) or any evidence of adhesion failure at the anodize/primer interface shall be cause for failure. 3.5 Touch Up Parts on which the anodic coating has been scratched or damaged superficially may be coated using AMS2473 or another method acceptable to the cogn

35、izant engineering organization. Touch-up, unless otherwise specified, shall not exceed 0.5 inches (13 mm) in its longest dimension, except that scratches that are essentially one dimensional (less than 0.03 inch (0.8 mm) wide) may be reworked. The total reworked area shall not exceed 5% of the total

36、 surface area. 3.6 Quality 3.6.1 Anodic coating, as received by purchaser, shall be continuous, smooth, adherent, and uniform in appearance, and shall be free from powdery areas, loose films, discontinuities, such as breaks or scratches (except at contact points), or other damage or imperfections de

37、trimental to usage of the coating. Slight discoloration from dripping, bleedout or rundown of the anodize or sealing solution from joints and recesses shall be acceptable 3.6.2 Parts sealed in sodium dichromate solution may have a characteristic yellow color, and those sealed in nickel acetate solut

38、ion may have a characteristic gray-green color. Slight variations in color between cast and machined surfaces, between welds and adjacent areas, due to grain size or grain flow variations, or due to variation in alloy composition from lot to lot, are acceptable. SAE AMS2470N Page 5 of 8 4. QUALITY A

39、SSURANCE PROVISIONS 4.1 Responsibility for Inspection The processor shall supply all samples for processors tests and shall be responsible for the performance of all required tests. Parts, if required for tests, shall be supplied by purchaser. Purchaser reserves the right to sample and to perform an

40、y confirmatory testing deemed necessary to ensure that processing conforms to specified requirements. 4.2 Classification of Tests 4.2.1 Acceptance Tests Quality (3.6) and color (3.3.2), if specified, are acceptance tests and shall be performed on parts, or samples representing parts when permitted,

41、from each lot. 4.2.2 Periodic Tests Coating weight (3.4.1), corrosion resistance (3.4.2), adhesive bond verification (3.4.3) when required by purchaser, and tests of cleaning and processing solutions to ensure that the anodic coating will conform to the specified requirements are periodic tests. Coa

42、ting weight and adhesive bond verification shall be performed at a frequency selected by the processor unless frequency of testing is specified by purchaser. Corrosion testing shall be performed monthly or at shorter intervals as directed by the cognizant engineering organization. 4.2.3 Preproductio

43、n Tests All property verification tests (3.4) are preproduction tests and shall be performed prior to or on the initial shipment of processed parts to a purchaser and when the purchaser deems confirmatory testing to be required. 4.3 Sampling and testing shall be not less than the following: a lot sh

44、all be all parts of the same part number processed in a continuous series of operations (3.3.1 to 3.3.3, inclusive), in not longer than 24 consecutive hours, and presented for the processors inspection at one time. 4.3.1 Acceptance and Preproduction Tests Test samples shall be randomly selected from

45、 the lot. The minimum number of samples shall be as shown in Table 1, and as follows. For preproduction tests for coating weight and corrosion resistance, sample quantity shall be selected by the processor unless quantity is specified by purchaser. 4.3.1.1 Adhesive bond verification tests (3.4.3) sh

46、all be determined on three samples fabricated from AMS4037 aluminum alloy, using dimensions in ASTM D 3762. TABLE 1 - SAMPLING FOR ACCEPTANCE TESTS Number of Parts In Lot Quality and Color Up to 7 8 to 15 16 to 40 41 to 110 111 to 300 301 to 500 Over 500 All 7 10 15 25 35 50 4.3.2 Periodic Tests Sam

47、ple quantity shall be selected at the discretion of the processor, unless otherwise specified. SAE AMS2470N Page 6 of 8 4.3.2.1 Coating weight shall be determined on representative parts when size and shape permit accurate determination of surface area. If parts are of such size and shape that surfa

48、ce area cannot be determined readily, coating weight determinations shall be made on separate test panels 0.025 to 0.063 inch (0.64 to 1.60 mm) thick and not less than 3 inches (76 mm) square fabricated from AMS4037 aluminum alloy. 4.3.2.1.1 Separate test panels, if used, shall be processed with the

49、 work they represent. 4.3.2.2 Corrosion resistance shall be determined on separate test panels 0.025 to 0.063 inch (0.64 to 1.60 mm) thick and not less than 3 10 inches (76 254 mm) in width and length fabricated from AMS4037 aluminum alloy. 4.4 Approval 4.4.1 Processes, control factors, or preproduction sample part or test panel, or any combination thereof specified, shall be approved by the cognizant engineering org