1、AEROSPACE MATERIAL SPECIFICATION AMS2406 REV. N Issued 1946-11 Revised 2015-01 Superseding AMS2406M Plating, Chromium Hard Deposit RATIONALE AMS2406N changes the hydrogen embrittlement relief requirement to the standard wording of 40 HRC for use with AMS2759/9, added hydrogen embrittlement relief re
2、quirement for hardnesses of 36-39 HRC and changes adhestion testing from an acceptance test to a periodic test. 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: AMS2406N Pl
3、ating thickness desired (See 3.4.1) Basis metal to be plated Tensile strength or hardness of the basis metal Pre-plate stress relief to be performed by plating processor (time and temperature) if different from 3.1.1 Special features, geometry or processing present on parts that requires special att
4、ention by the plating processor Hydrogen embrittlement relief to be performed by plating processor (parameters or reference document) if different from 3.3. Minimum thickness on internal surfaces, if required (See 3.4.1.2) Optional: Sample quantity and frequency of periodic testing (See 4.2.2 and 4.
5、3.2) Whether approval is based on approval of process/control factors or sample part or both (See 4.4.1) Quantity of pieces to be plated 2) Parts manufacturing operations such as heat treating, forming, joining and media finishing can affect the condition of the substrate for plating, or if performe
6、d after plating, could adversely affect the plated part. The sequencing of these types of operations should be specified by the cognizant engineering organization and is not controlled by this specification. _ SAE Technical Standards Board Rules provide that: “This report is published by SAE to adva
7、nce 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 therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least ev
8、ery five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2015 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by
9、 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 USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.s
10、ae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AMS2406N SAE INTERNATIONAL AMS2406N Page 2 of 7 1. SCOPE 1.1 Purpose This specification covers the requirements for electrodeposited hard chromium plate. 1.2 Application Thi
11、s plating has been used typically on parts for increasing abrasion resistance, increasing tool and die life, maintaining accuracy of gauges, and reconditioning worn or undersized parts, but usage is not limited to such applications. 1.3 Safety-Hazardous Materials While the materials, methods, applic
12、ations, and processes described or referenced 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 hazar
13、dous materials and to take necessary precautionary 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 suppl
14、ier may work to a subsequent revision of a document unless a specific document issue is specified. When the referenced document has been canceled and no superseding document has been specified, the last published issue of that document shall apply. 2.1 SAE Publications Available from SAE Internation
15、al, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AMS2759/9 Hydrogen Embrittlement Relief (Baking) of Steel 2.2 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West C
16、onshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM B253 Preparation of Aluminum Alloys for Electroplating ASTM B487 Measurement of Metal and Oxide Coating Thicknesses by Microscopical Examination of a Cross Section ASTM B499 Measurement of Coating Thicknesses by the Magnetic Method: N
17、onmagnetic Coatings on Magnetic Basis Metals ASTM B504 Measurement of Thickness of Metallic Coatings by the Coulometric Method ASTM B567 Method for Measurement of Coating Thickness by the Beta Backscatter Method ASTM B568 Measurement of Coating Thickness by X-Ray Spectrometry ASTM B571 Qualitative A
18、dhesion Testing of Metallic Coatings ASTM B748 Measurement of Thickness of Metallic Coatings by Measurement of Cross Section with a Scanning Electron Microscope ASTM E384 Knoop and Vickers Hardness of Materials ASTM F519 Mechanical Hydrogen Embrittlement Evaluation of Plating Processes/Coating and S
19、ervice Environments SAE INTERNATIONAL AMS2406N Page 3 of 7 3. TECHNICAL REQUIREMENTS 3.1 Preparation 3.1.1 Stress Relief Treatment All steel parts having a hardness of 40 HRC and above and that are machined, ground, cold formed or cold straightened shall be cleaned to remove surface contamination an
20、d thermally stress relieved before plating. Temperatures to which parts are heated shall be such that maximum stress relief is obtained while still maintaining hardness of parts within drawing limits. (Residual tensile stresses have been found to be damaging during electrofinishing.) Unless otherwis
21、e specified, the following treatment temperatures and times shall be used: 3.1.1.1 For parts, excluding nitrided parts, having a hardness of 55 HRC and above, including carburized and induction hardened parts, stress relieve at 275 F 25 (135 C 14) for a minimum of 5 hours. 3.1.1.2 For parts having a
22、 hardness less than 55 HRC, stress relieve at 375 F 25 (191 C 14) for a minimum of 4 hours. Nitrided parts fall into this category. Higher temperatures shall be used only when specified or approved by the cognizant engineering organization. 3.1.1.3 For peened parts: If stress relief temperatures abo
23、ve 375 F (191 C) are elected, the stress relieve shall be performed prior to peening or the cognizant engineering organization shall be consulted and shall approve the stress relief temperature. 3.1.2 The plating shall be applied over a surface free from water breaks. The cleaning procedure shall no
24、t produce pitting or intergranular attack of the basis metal and shall preserve dimensional requirements. 3.1.3 Except for barrel plating, electrical contact points shall be as follows: For parts which are to be plated all over, locations shall be specified or approved by the cognizant engineering o
25、rganization. For parts which are not to be plated all over, locations shall be in areas on which plating is not required, or locations shall be specified or approved by the cognizant engineering organization. 3.1.4 Prior to plating, aluminum alloys shall be zincate treated in accordance with ASTM B2
26、53 or other method specified or approved by the cognizant engineering organization. 3.2 Procedure 3.2.1 The chromium shall be deposited directly on the basis metal without a flash coating of other metal underneath, except in the case of parts made of maraging steels, corrosion-resistant steels, or a
27、luminum alloys, on which a preliminary deposit of nickel or other suitable metal 0.0002 inch (5 m) thickness maximum is permissible. 3.3 Hydrogen Embrittlement Relief Treatment of steel parts 40 HRC and above shall be in accordance with AMS2759/9. For steel parts 36-39 HRC, regardless of alloy type,
28、 treatment shall be in accordance with AMS2759/9 using the minimum bake soak times specified in Table 1 for “Lower Strength Carbon, Low-Alloy, Tool Steel“. 3.4 Properties 3.4.1 Thickness Thickness of the plate shall be as specified on the drawing, determined in accordance with any of the following m
29、ethods as applicable: ASTM B487, ASTM B499, ASTM B567, ASTM B568, ASTM B748, or by other method permitted by the cognizant engineering organization. 3.4.1.1 The plate shall be substantially uniform in thickness on significant surfaces except that build-up at exterior corners or edges will be permitt
30、ed provided finished drawing dimensions are met. SAE INTERNATIONAL AMS2406N Page 4 of 7 3.4.1.2 All surfaces of the part, except those which cannot be touched by a sphere 0.75 inch (19 mm) in diameter, shall be plated to the thickness specified. Unless otherwise specified, these surfaces, such as ho
31、les, recesses, threads, and other areas where a controlled deposit cannot be obtained under normal plating conditions, may be under specified limits provided they show coverage. 3.4.2 Hardness The plate hardness shall be not lower than 700 HV, or equivalent, determined in accordance with ASTM E384 u
32、sing a Vickers indenter and 100 gram load 3.4.3 Adhesion Adhesion shall meet the requirements of ASTM B571 Bend Test method with no mandrel. When examined at a magnification of approximately 4X, neither the chromium plating nor any electrodeposited underplate(s) shall show separation from the basis
33、metal or from each other. The formation of cracks in the plating or the basis metal which do not result in flaking, peeling or blistering of plated layers shall not be cause for rejection. 3.4.4 Hydrogen Embrittlement The chromium plating process, after baking, shall not cause hydrogen embrittlement
34、 in steel parts 36 HRC and over, determined in accordance with the requirements of ASTM F519. See 4.3.3.2. 3.5 Quality Plating, as received by purchaser, shall be firmly bonded to the basis metal, and shall be smooth and uniform in appearance and, except as noted in 3.5.1, shall be bright, free from
35、 frosty areas, pinholes, nodules, blisters, and other imperfections detrimental to performance of the deposit. Visual inspection may be aided by not greater than 5X magnification. 3.5.1 Pinholes and other imperfections which can be shown to be the result of failure of the deposit to bridge or fill i
36、mperfections, such as porosity, in the surface of the basis metal are acceptable. 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 required tests. Where parts are to be
37、tested, such parts 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 specified requirements. 4.2 Classification of Tests 4.2.1 Acceptance Tests Thickness (3.4.1), and quality (3.5) are
38、 acceptance tests and shall be performed on each lot. 4.2.2 Periodic Tests Hardness (3.4.2) is a periodic test and shall be performed at least quarterly unless frequency of testing is specified by the cognizant engineering organization. Adhesion (3.4.3) is a periodic test that shall be performed no
39、less than daily for each generic class of alloy as defined by AS2390 processed during that day Tests of cleaning and plating solutions are periodic tests and shall be performed at a frequency established by the processor unless frequency of testing is specified by the cognizant engineering organizat
40、ion. See 4.4.3 and 8.4. Hydrogen embrittlement (3.4.4) is a periodic test and shall be determined at least once in each month that steel parts 36 HRC and over are plated. 4.2.3 Preproduction Tests All property verification tests are preproduction tests and shall be performed when prior to initial sh
41、ipment and when the cognizant engineering organization deems confirmatory testing to be required. SAE INTERNATIONAL AMS2406N Page 5 of 7 4.3 Sampling and testing shall be as follows; a lot shall be all parts of the same part number processed in a continuous operation, to the same thickness range, in
42、 the same set of solutions, in not longer than 24 consecutive hours, and presented for processors inspection at one time. 4.3.1 Acceptance Tests Test samples shall be selected randomly from all parts in the lot. Unless the cognizant engineering organization supplies a sampling plan, the minimum numb
43、er of samples shall be as shown in Table 1. TABLE 1 - Sampling for Acceptance Testing Number of Parts in Lot Quality Thickness Up to 7 8 to 15 16 to 40 41 to 110 111 to 300 301 to 500 501 to 700 701 to 1200 Over 1200 All 7 10 15 25 35 50 75 125 All or 3* 4 4 5 6 7 8 10 15 *Whichever is less 4.3.2 Pe
44、riodic and Preproduction Tests Sample quantity shall be one for hardness and as specified in ASTM F519 for hydrogen embrittlement unless otherwise specified by the cognizant engineering organization. For adhesion tests, four test specimens of each generic class of alloy, as defined by AS2390, that h
45、ave been be processed through the same cleaning and plating operations as the parts that they represent. These adhesion test specimens shall be processed prior to the first production lot of parts or with the first production lot of parts. 4.3.3 Sample Configuration 4.3.3.1 Separate test specimens m
46、ay be used under any one of the following circumstances: the plated parts are of such configuration or size as to be not readily adaptable to the specified tests or when nondestructive testing is not practical on actual parts, or it is not economically acceptable to perform destructive tests on actu
47、al parts. When used, separate test specimens shall be of the same generic class of alloy as the parts, distributed within the lot, cleaned, plated, and post-treated with the parts. 4.3.3.2 Hydrogen embrittlement test specimens shall conform to ASTM F519 Type 1a.1 using notched round bars, stressed i
48、n tension under sustained load unless a different specimen is specified by the cognizant engineering organization. For test purposes, plating thickness shall be 0.002 inch 0.0002 (51 m 5), measured on the smooth section of the specimen, but with visual evidence of plating in the root of the notch. T
49、esting beyond the 200 hour test period is not required. 4.4 Approval 4.4.1 The process and control procedures, a preproduction sample part, or both, whichever is specified, shall be approved by the cognizant engineering organization 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 fo
