SAE AMS 2472G-2014 Anodic Treatment of Aluminum Alloys Sulfuric Acid Process Dyed Coatings.pdf

1、AEROSPACE MATERIAL SPECIFICATION AMS2472 REV. G Issued 1965-02 Revised 2014-11 Superseding AMS2472F Anodic Treatment of Aluminum Alloys Sulfuric Acid Process, Dyed Coatings RATIONALE AMS2472G results from a Five Year Review and update of this specification. NOTICE ORDERING INFORMATION: The following

2、 information shall be provided to the processor by the purchaser. 1) Purchase order shall specify not less than the following: AMS2472G Basis metal to be anodized Required color Special features, geometry or processing present on parts that requires special attention by the processor Quantity of pie

3、ces to be anodized 2) Parts manufacturing operations such as heat treating, forming, joining and 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

4、 or purchaser and is not controlled by this specification. 1. SCOPE 1.1 Purpose This specification establishes the requirements for dyed anodic coatings on aluminum alloys. 1.2 Application This process has been used typically to increase corrosion resistance and to produce colored surfaces on alumin

5、um alloy parts, but usage is not limited to such applications. 1.2.1 AMS2470 or AMS2471 should be specified for coatings to be used as a base for paint or other organic finishes. This process is not suitable for parts which contain joints or recesses in which the anodizing solutions may be retained.

6、 _ 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 ther

7、efrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2014 SAE International All rights reserved. No part of this

8、publication may 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: +1 724-776-49

9、70 (outside USA) 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/AMS2472G SAE INTERNATIONAL AMS2472G Page 2 of 7 1.3 Classification This specific

10、ation covers two types of coating classified as follows: Class 1 - Coatings for Identification Class 2 - Coatings for Decorative Purposes When no class is specified, Class 1 shall be supplied. 1.4 Safety - Hazardous Materials While the materials, methods, applications, and processes described or ref

11、erenced 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 p

12、recautionary measures 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, Warrendal

14、e, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AMS2470 Anodic Treatment of Aluminum Alloys, Chromic Acid Process AMS2471 Anodic Treatment of Aluminum Alloys, Sulfuric Acid Process, Undyed Coating AMS2473 Chemical Film Treatment for Aluminum Al

15、loys, 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, Tel: 610-832-958

16、5, www.astm.org. ASTM B 117 Operating Salt Spray (Fog) Testing Apparatus ASTM B 137 Measurement of Mass of Coating on Anodically Coated Aluminum 3. TECHNICAL REQUIREMENTS 3.1 Solutions 3.1.1 Electrolyte shall be an aqueous solution of sulfuric acid of suitable concentration (8.2.2) maintained within

17、 2 F ( 1 C) of the temperature approved in 4.4.3. 3.1.2 Dye shall be as required to produce the specified color. 3.1.3 Sealer shall be an aqueous solution of nickel acetate or cobalt acetate or other solution permitted by the cognizant engineering organization. See 8.2.3. SAE INTERNATIONAL AMS2472G

18、Page 3 of 7 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. 3.2.2 Masking Areas where anodizing is prohibited shall be masked. 3.2.3 Tight electrical contact shall be maintained during the anodic treatme

19、nt to prevent contact arcing (burning) of parts, but small irregularities of coating at points of electrical contact are acceptable. Electrical contact locations shall be in areas where anodizing is not required (if anodizing is not required on all surfaces), or, shall be as specified or approved by

20、 the cognizant engineering organization. 3.3 Procedure 3.3.1 Anodizing The cleaned parts shall be made the anode(s) in the electrolyte contained in a chemical- resistant tank which may also serve as the cathode. The processing shall be adjusted to obtain the required weight and quality of the coatin

21、gs. The anodizing current shall be maintained within 2 amperes per square foot (21.5 A/m2) of the nominal value. Alternatively, the anodizing current shall be ramped up over a five minute, or other preselected period, to the desired final voltage and maintained until the anodic coating reaches the d

22、esired thickness. After anodizing, parts shall be rinsed thoroughly in water at ambient temperature. 3.3.2 Dyeing Prior to sealing, parts shall be dyed to the specified color by immersing in a appropriate dye solution. The temperature of the solution and the time of immersion shall be as necessary t

23、o produce the specified color. Parts shall then be rinsed in clean water at ambient temperature. 3.3.3 Sealing Parts shall be immersed in the sealer solution for a suitable time. See 8.2.11. After sealing, the parts shall be thoroughly rinsed in clean water at ambient temperature, rinsed in clean ho

24、t water, and dried. 3.4 Properties Coated parts shall conform to the following requirements: 3.4.1 Coating Weight The undyed and unsealed coating weight (4.3.2.1) shall be determined in accordance with ASTM B 137 and shall comply with Table 1. TABLE 1 - COATING WEIGHT REQUIREMENTS Class Minimum Coat

25、ing Weight, mg/square foot (g/m2) 1 600 ( 6.5) 2 2500 (27) 2 (high copper content alloys*) 1400 (15) *Wrought aluminum alloys of the 2000 series where copper is the major alloying element and aluminum casting alloys with a nominal copper content of 1% or higher. 3.4.1.1 If small parts, such as rivet

26、s 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. In no case shall any part show uncoated areas. SAE INTERNATIONAL AMS2472G Page 4 of 7 3.4.2 Corrosion Resistance Panel

27、s (4.3.2.2) shall 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 vertical. The five test panels shall show not more than a total of

28、 15 isolated pits none larger than 1/32 inch in diameter, in a total of 150 sq inches (968 cm2) of test area. Areas within 1/16 inch (1.6 mm) of identification markings or of an edge, or at electrode contact marks shall not be included. Individual test specimens shall show no more than five isolated

29、 pits none larger than 1/32 inch in a total of 30 sq. inches (194 cm2). See 8.3.1. 3.5 Touch Up Damaged areas of parts on which the anodic coating has been scratched or damaged superficially may be coated using AMS2473 or other method permitted by the cognizant engineering organization. Touch up, un

30、less otherwise specified, shall not exceed 0.5 inch (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 surface area. 3.6 Quality Anodic coating, as

31、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 detrimental to usage of the coating. Slight variations

32、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. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The coating processor shall supply al

33、l 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 any confirmatory testing deemed necessary to ensure that processing conforms to speci

34、fied requirements. 4.2 Classification of Tests 4.2.1 Acceptance Tests Quality (3.6) and color (3.3.2) are acceptance tests and shall be performed on parts, or samples representing parts when permitted, from each lot. 4.2.2 Periodic Tests Coating weight (3.4.1) and corrosion resistance (3.4.2) are pe

35、riodic tests and shall be performed at least monthly in any month that parts are processed unless frequency of testing is specified by the purchaser. Tests of cleaning and processing solutions are periodic tests and shall be performed at a frequency established by the processor unless frequency of t

36、esting is specified by purchaser. See 8.4 and 4.4.3. 4.2.3 Preproduction Tests All property verification tests (section 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 cognizant engineering organization requires c

37、onfirmatory testing. 4.3 Sampling and testing shall be not less than the following: a lot shall 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 processors inspection at one tim

38、e. 4.3.1 Acceptance tests Test samples shall be randomly selected from the lot. The minimum number of samples shall be as shown in Table 2. SAE INTERNATIONAL AMS2472G Page 5 of 7 TABLE 2 - SAMPLING FOR ACCEPTANCE TESTING Number of Parts In Lot Quality and Color Up to 7 8 to 15 16 to 40 41 to 110 111

39、 to 300 301 to 500 Over 500 All or 7* 7 10 15 25 35 50 * Whichever is less 4.3.2 Periodic Tests Sample quantity shall be selected at the discretion of the processor, unless otherwise specified. 4.3.2.1 Coating weight shall be determined on representative parts when size and shape permit accurate det

40、ermination of surface area. If parts are of such size and shape that surface 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 2024 aluminum allo

41、y in accordance with AMS4037. 4.3.2.1.1 Separate test panels, if used, shall be processed with the work they represent. 4.3.2.2 Corrosion resistance shall be determined on five separate test panels 0.025 to 0.063 inch (0.64 to 1.60 mm) thick and not less than 3 x 10 inches (76 x 254 mm) in width and

42、 length fabricated from 2024 aluminum alloy in accordance with AMS4037. Total surface area is 150 square inches (968 cm2). 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 o

43、rganization before production parts are supplied. 4.4.2 If the processor makes a significant change to any material, process, or control factor from that which was used for process approval, all preproduction tests shall be performed and the results submitted to the cognizant engineering organizatio

44、n for process reapproval, unless the change is approved by the cognizant engineering organization. A significant change is one which, in the judgment of the cognizant engineering organization, could affect the properties or performance of the parts. Production parts anodized by the revised procedure

45、 shall not be shipped prior to receipt of reapproval. 4.4.3 Control factors for anodizing shall include, but not be limited to, the following: Cleaning procedure, including the compositions and temperatures of the baths used Deoxidation process Anodizing bath composition including impurity limits, t

46、emperature, and agitation method Rate of voltage rise, anodizing voltage, and time of anodizing Sealing solution composition including impurity limits, temperature, and pH Dye solution composition and temperature Touch up, method if used Purity of water used for sealing and rinsing Periodic test pla

47、n for cleaning and processing solutions. See 8.4. 4.5 Reports The processor shall furnish with each shipment a report stating that the parts have been processed and tested in accordance with the requirements of this specification and that they conform to all test requirements. This report shall incl

48、ude the purchase order number, lot identification number, AMS2472G, part number, and quantity. SAE INTERNATIONAL AMS2472G Page 6 of 7 4.6 Resampling and Retesting 4.6.1 If any acceptance test fails to meet specified test requirements, the parts in that lot may be stripped, pretreated, coated, post t

49、reated as defined herein, and retested. Alternatively, all parts in the lot may be inspected for the nonconforming attribute, and the nonconforming parts may be stripped, pretreated, coated, post treated as defined herein, and retested. After stripping and reanodizing, parts shall meet the dimensions on the drawing. 4.6.1.1 When stripping is performed, the method shall be permitted by the cognizant engineering organizat