SAE AMS 2434E-2017 Plating Tin-Zinc Alloy.pdf

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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 ther

2、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 2017 SAE International All rights reserved. No part of this

3、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

4、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:/standards.sae.org/AMS2434E AEROSPACE MATERIAL SPECIFICATION AMS2434 REV. E Issued 1998-07 Revised 2017-11 Supers

5、eding AMS2434D Plating, Tin-Zinc Alloy RATIONALE AMS2434E results from a Five-Year Review and update of this specification with technical changes to Ordering Information, classification (1.3, 1.3.1, 1.3.2), stress relief treatment (3.1.2, 3.1.2.1, 3.1.2.2, 3.1.2.3), activating treatment (3.1.7), typ

6、e 2 treatments (3.3.2, 3.3.2.1, 3.3.2.2, 3.3.2.3), thickness (3.4.1, 3.4.1.3), hydrogen embrittlement (3.4.5), solderabilty (3.4.6), acceptance tests (4.2.1), periodic tests (4.2.2), sampling for acceptance tests (Table 2), sampling for periodic tests (4.3.2), hydrogen embrittlement test and specime

7、ns (4.3.3.3) and adhesion test specimens (4.3.3.4). NOTICE ORDERING INFORMATION: The following information shall be provided to the plating processor by the purchaser. 1. Purchase order shall specify not less than the following: AMS2434E and plating Type and Grade (see 1.3). Plating thickness desire

8、d (see 3.4.1). Basis metal to be plated. Copper underplating, if required for soft soldering (see 8.7). Tensile strength or hardness of the basis metal. Pre-plate stress relief to be performed by plating processor (time and temperature) if different from 3.1.2. Special features, geometry or processi

9、ng present on parts that requires special attention by the plating processor. Permissible electrical contact locations, if not specified Hydrogen embrittlement relief to be performed by plating processor (parameters or reference document) if different from 3.3. Minimum thickness on internal surfaces

10、, if required (see 3.4.1.1). Solderability, if required (see 3.4.6). Optional: Periodic testing frequency (see 4.2.2) and sample quantity (see 4.3.2). Quantity of pieces to be plated. 2. Parts manufacturing operations such as heat treating, forming, joining and media finishing can affect the conditi

11、on of the substrate for plating, or if performed after plating, could adversely affect the plated 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. SAE INTERNATIONAL AMS2434E Page

12、2 of 9 1. SCOPE 1.1 Purpose This specification covers the requirements for electrodeposited tin-zinc alloy plating. 1.2 Application This plating has been used typically as a corrosion resistant plating where cadmium cannot be used, as a replacement for tin plating where tin whisker growth is a conce

13、rn, a coating for fasteners where thread lubricity is desirable, and for parts which are to be joined using tin-lead solders, but usage is not limited to such applications. 1.3 Classification Plating covered by this specification is classified as follows: Type 1 - As plated Type 2 - With supplementa

14、ry chromate treatment. Grade A - Hexavalent chromate treatment, service temperature 250 F (121 C) maximum. Grade B - Trivalent chromium treatment, service temperature 375 F (191 C) maximum. 1.3.1 Unless a Type is specified, Type 2 shall be supplied. 1.3.2 For Type 2 plating, if no grade is specified

15、, Grade A shall be supplied. Processors have the option of using Grade B if permitted by the cognizant engineering organization. 1.4 Safety - Hazardous Materials While the materials, methods, applications and processes described or referenced in this specification may involve the use of hazardous ma

16、terials, this specification does not address the hazards that 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 the necessary precautionary measures to ensure the health and safety of all p

17、ersonnel 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 of a document unless a specific document issue is specified. W

18、hen 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, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or

19、 +1 724-776-4970 (outside USA), www.sae.org. AMS2418 Plating, Copper AMS4751 Tin - Lead Eutectic 63Sn - 37Pb ARP1917 Clarification of Terms Used in Aerospace Metals Specifications AS2390 Chemical Process Test Specimen Material SAE INTERNATIONAL AMS2434E Page 3 of 9 2.2 ASTM Publications Available fr

20、om ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM B32 Solder Metal ASTM B117 Operating Salt Spray (Fog) Apparatus ASTM B253 Preparation of Aluminum Alloys for Electroplating ASTM B374 Terminology Relating to Electropl

21、ating ASTM B487 Measurement of Metal and Oxide Coating Thickness by Microscopic Examination of Cross-Section ASTM B499 Measurement of Coating Thickness by the Magnetic Method: Nonmagnetic Coatings on Magnetic Basis Metals ASTM B504 Measurement of Thickness of Metallic Coatings by the Coulometric Met

22、hod ASTM B567 Measurement of Coating Thickness by the Beta Backscatter Method ASTM B568 Measurement of Coating Thickness by X-Ray Spectrometry ASTM B571 Qualitative Adhesion Testing of Metallic Coatings ASTM F519 Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service E

23、nvironments 3. TECHNICAL REQUIREMENTS 3.1 Preparation 3.1.1 Unless otherwise specified, parts shall be within drawing dimensions before plating, except as specified in 3.1.1.1. 3.1.1.1 All engine and propeller utility parts having numbers with prefix AN, AS, or MS, required to be plated in accordanc

24、e with this specification, shall be made to such dimensions that parts will be within drawing limits after plating. Undercutting before plating shall not be permitted unless authorized by purchaser. 3.1.2 Stress Relief Treatment All steel parts having a hardness of 40 HRC and above and that are mach

25、ined, ground, cold formed or cold straightened after heat treatment shall be cleaned to remove surface contamination and thermally stress relieved before plating. (Residual tensile stresses have been found to be damaging during electroplating.) Furnaces used for stress relief shall be controlled per

26、 AMS2750; the minimum requirements shall be Class 5 and Type D Instrumentation. Temperatures to which parts are heated shall be such that stress relief is obtained while still maintaining hardness of parts within drawing limits. Unless otherwise specified, the following treatment temperatures and ti

27、mes shall be used: 3.1.2.1 For parts, excluding nitrided parts, having a hardness of 55 HRC and above, and for carburized and induction hardened parts, stress relieve at 275 F 25 (135 C 14) for 5 to 10 hours. 3.1.2.2 For parts having a hardness less than 55 HRC, and for nitrided parts, stress reliev

28、e at 375 F 25 (191 C 14) for a minimum of 4 hours. Higher temperatures shall be used only when specified or approved by the cognizant engineering organization. 3.1.2.3 For peened parts: If stress relief temperatures above 375 F (191 C) are elected, the stress relieve shall be performed prior to peen

29、ing or the cognizant engineering organization shall be consulted and shall approve the stress relief temperature. SAE INTERNATIONAL AMS2434E Page 4 of 9 3.1.3 The plating shall be applied over a surface free from water breaks. The cleaning procedure shall not produce pitting or intergranular attack

30、of the basis metal and shall preserve dimensional requirements. 3.1.4 Unless otherwise specified, a wet or dry abrasive cleaning that does not change dimensions of the part may be used to assist adhesion of the plate. 3.1.5 Except for barrel plating, electrical contact points shall be as follows. Fo

31、r parts which are to be plated all over, locations shall be acceptable to purchaser. For parts which are not to be plated all over, locations shall be in areas on which plating is not required. 3.1.6 Aluminum alloys shall be zincate or stannate treated in accordance with ASTM B253 or other method ac

32、ceptable to the cognizant engineering organization prior to plating. 3.1.7 Nickel or cobalt alloys and corrosion resistant steels shall be given an activating treatment, such as nickel strike, prior to tin-zinc plating. 3.2 Procedure 3.2.1 Except as noted or otherwise specified, tin-zinc shall be el

33、ectrodeposited directly on the basis metal from a suitable tin-zinc solution. See 8.7 if soft soldering is required. 3.2.2 Spotting-in and double plating are not permitted. 3.3 Post Treatment 3.3.1 Parts shall be given a hydrogen embrittlement relief or adhesion enhancement treatment in a circulatin

34、g air furnace in accordance with Table 1 (see 8.2). Treatment shall begin within four hours of the completion of the plating operation. Table 1 - Post plating baking conditions Material Temperature Time, Hours Minimum Carburized parts 275 F 25 F (135 C 14 C) 23 Other steels over 55 HRC 275 F 25 F (1

35、35 C 14 C) 23 Steel parts 40 HRC and higher 340 F 25 F (171 C 14 C) 12 Threaded fasteners 31 HRC and higher 340 F 25 F (171 C 14 C) 12 PH steels and aged below 1000 F (538 C) 340 F 25 F (171 C 14 C) 12 Adhesion enhancement, Aluminum Alloy parts (see 8.7) 225 F 25 F (107 C 14 C) 1 Adhesion enhancemen

36、t, other alloys (optional) 225 F 25 F (107 C 14 C) 1 3.3.2 Type 2 Treatments 3.3.2.1 Type 2 parts shall be subjected to a chemical conversion process that retards the formation of white corrosion product sufficiently to meet the requirements of 3.4.4.2. Waxes, oils, or other water repellant systems

37、shall not be used for this purpose. 3.3.2.2 Grade A parts shall receive a hexavalent chromate conversion treatment. When hydrogen embrittlement relief baking is required by Table 1, the treatment shall be applied after baking and surface reactivation. 3.3.2.3 Grade B parts shall receive a trivalent

38、chromium conversion treatment. When hydrogen embrittlement relief baking is required by Table 1, the treatment shall be applied prior to baking. SAE INTERNATIONAL AMS2434E Page 5 of 9 3.4 Properties 3.4.1 Thickness Thickness of the plated deposit shall be as specified on the engineering drawing, det

39、ermined by a dimensional gaging method (see 3.4.1.3) or in accordance with any of the following methods as applicable: ASTM B487, ASTM B499, ASTM B504, ASTM B567, ASTM B568 or other method acceptable to purchaser. 3.4.1.1 All surfaces of the part, except those which cannot be touched by a sphere 0.7

40、5 inch (19 mm) in diameter, shall be plated to the specified thickness. Unless otherwise specified, surfaces such as holes, recesses, threads and other areas where a controlled deposit cannot be obtained under normal plating conditions, may be under the specified limit provided they show visual plat

41、ing coverage. 3.4.1.2 Where a tin-zinc flash plate is specified, plate thickness shall be approximately 0.0001 inch (2.5 m). 3.4.1.3 Dimensional gauging (micrometers, verniers, pin gages, dial bore gages, height gages, or coordinated measuring machines, as examples) shall be maintained in accordance

42、 with ANSI/NCSL Z540.3. Resolution of the calibrated measuring instrument used, shall be not less than ten times more precise than the attribute being measured. 3.4.2 Composition The plated deposit shall have a composition of 70 to 90% tin and 10 to 30% zinc, as determined by a method acceptable to

43、the cognizant engineering organization (see 8.8). In case of dispute, one or more of the parts may be stripped of coating, and the resultant solution analyzed by conventional wet chemical methods for relative proportions of tin and zinc. 3.4.3 Adhesion Adhesion shall meet the requirements of the hea

44、t quench method described in ASTM B571 for tin plating. 3.4.4 Corrosion Resistance 3.4.4.1 Type 1 Parts or specimens having a plate thickness of 0.0003 to 0.0005 inch (8 to 13 m) shall not show basis metal corrosion after 96 hours of continuous salt spray test, conducted in accordance with ASTM B117

45、. 3.4.4.2 Type 2 Parts or specimens having a plate thickness of 0.0003 to 0.0005 inch (8 to 13 m) shall show neither white corrosion product after 96 hours of continuous salt spray test nor basis metal corrosion after 500 hours of continuous salt spray test conducted in accordance with ASTM B117. Th

46、e presence of white corrosion product within 0.25 inch (6.4 mm) from the edges of the specimen shall not constitute failure. 3.4.5 Hydrogen Embrittlement The plating process after baking (see 8.2) shall not cause hydrogen embrittlement in steel parts 36 HRC and over determined in accordance with AST

47、M F519, Type 1a.1. 3.4.6 Solderability When specified, Type 1 deposits shall demonstrate acceptable solderability using tin-lead solder in accordance with AMS4751, or ASTM B32 Grade SN63 or solder material as approved by the cognizant engineering organization, and using a mildly reactive rosin (RMA)

48、 flux. The solder shall flow uniformly and shall show no evidence of dewetted areas. 3.5 Quality Plating shall be smooth, continuous, free of delamination within the plating, uniform in appearance, and free of imperfections detrimental to usage of the plating. Plating shall be visually free from fro

49、sty areas, pinholes, porosity, blisters, nodules, and pits. Slight discoloration or staining is permitted. SAE INTERNATIONAL AMS2434E Page 6 of 9 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The processor shall supply all specimens for processors tests and shall be responsible for the performance of all