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 2012 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/AMS2460A AEROSPACE MATERIAL SPECIFICATION AMS2460 REV. A Issued 2007-07 Revised 2013-03 Super
5、seding AMS2460 Plating, Chromium RATIONALE AMS2460A results from a Five Year Review and includes additional details for basis metal quality and for stress relief of steel parts before plating. NOTICE ORDERING INFORMATION: The following information shall be provided to the plating processor by the pu
6、rchaser: 1) Purchase Orders shall specify not less than the following: AMS2460A Part number and quantity of pieces to be plated Class of plating. See 1.4.1. For Class 1 plating, type of surface luster. See 1.4.2 and 3.5.1.2. Plating thickness. See 3.4.1. Underplating, if different from 3.3.2 Basis m
7、etal to be plated Tensile strength or hardness of the basis metal Pre-plate stress relief (time and temperature) if different from 3.2.1, or instructions that pre-plate stress relief has already been performed prior to submitting parts to the plating processor, or statement that pre-plate stress rel
8、ief is not required Plating coverage; special features, geometry or processing present on parts that requires special attention by the plating processor Hydrogen embrittlement relief to be performed by the plating processor (parameters or requirements document), if different from 3.3.4 Peening requi
9、rements, if peening is required to be performed by the plating processor. See 3.1.3 and 8.4.1. If tests for hardness, porosity, or hydrogen embrittlement are required for lot acceptance. See 4.2.1. If adhesion is to be evaluated by grinding. See 3.4.2.1. and responsibility (plating processor or part
10、 fabricator) to perform this evaluation. 2) Parts manufacturing operations such as heat treating, forming, joining, and media finishing can affect the condition of the substrate for plating, or if performed after plating, could adversely affect the plated part. The sequencing of these types of opera
11、tions should be specified by the cognizant engineering organization or purchaser and is not controlled by this specification, except as noted herein. Requirements for basis metal quality (3.1.1), peening (3.1.3), and preplating stress relief (3.2.1) require special coordination with the plating proc
12、essor. SAE AMS2460A Page 2 of 14 1. SCOPE 1.1 Purpose This specification covers the requirements for electrodeposited chromium plating. 1.2 Application This plating has been used typically as a decorative finish, to improve corrosion resistance, to increase wear resistance, to extend tool and die li
13、fe, to maintain accuracy of gauges, and to recondition worn or undersized parts, but usage is not limited to such applications. While this document is primarily intended to address electrodeposition on steels, the process has been performed on aluminum, heat resistant alloys, high nickel alloys, sup
14、er alloys, and other metals. The requirements of this specification are equivalent to AMS-QQ-320 but generally more stringent than AMS2406A. Thin Dense Chrome plating should be specified by reference to AMS2438. 1.2.1 Restriction Application of chromium plating to steel parts having a hardness of 48
15、 HRC (ultimate tensile strength of 238 ksi 1641 MPa) or higher shall not be performed unless authorized by the design documentation of the cognizant engineering organization. (See 4.2.3.1 and 8.4.2.) Application of chromium plating for repair of steel parts having a hardness of 48 HRC(ultimate tensi
16、le strength of 238 ksi (1641 Mpa) or higher requires a special design evaluation and shall not be performed unless specific approval has been received from the cognizant engineering organization 1.3 Safety-Hazardous Materials While the materials, methods, applications and processes described or refe
17、renced 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 responsibility of the user to ensure familiarity with the safe and proper use of any hazardous materials, to take precautionary measur
18、es to ensure the health and safety of all personnel involved. 1.4 Classification 1.4.1 Classes Electrodeposited chromium plating shall be one of the following classes. Class 1 - Corrosion protective plating. See 8.4.3. Class 2 - Engineering plating. See 8.4.4. 1.4.2 Appearance Class 1 plating shall
19、have one of the following types of lusters, as specified. Type I - Bright finish Type II - Satin finish. 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 t
20、o a subsequent revision 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. SAE AMS2460A Page 3 of 14 2.1 SAE Publications Available from SA
21、E International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AMS2403 Plating, Nickel, General Purpose AMS2406 Plating, Chromium, Hard Deposit AMS2438 Plating, Chromium, Thin, Hard, Dense Deposit AMS2759/9 Hy
22、drogen Embrittlement Relief (Baking) of Steel Parts AMS-QQ-C-320 Chromium Plating, Electrodeposited AMS-QQ-N-290 Nickel Plating (Electrodeposited) 2.2 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.a
23、stm.org. ASTM B 253 Standard Guide for Preparation of Aluminum Alloys for Electroplating ASTM B 487 Measurement of Metal and Oxide Coating Thickness by Microscopic Examination of a Cross Section ASTM B 499 Measurement of Coating Thick nesses by the magnetic Method: Nonmagnetic Coatings on Magnetic B
24、ase Metals ASTM B 504 Measuring the Thickness of Metallic Coatings by the Coulometric Method ASTM B 556 Thin Chromium Coatings by the Spot Test, Guideline for Measurement of ASTM B 567 Method for Measurement of Coating Thickness by Beta Backscatter Method ASTM B 568 Measurement of Coating Thickness
25、by X-Ray Spectrometry ASTM B 571 Qualitative Adhesion of Metallic Coatings ASTM B 748 Measurement of Thickness of Metallic Coatings by Measurement of Cross Section with a Scanning Electron Microscope ASTM B 764 Simultaneous Thickness and Electrochemical Potential Determination of Individual Layers o
26、n the Multilayer Nickel Deposit (STEP Test) ASTM E 384 Test Method for Microhardness of Materials ASTM F 519 Mechanical Hydrogen Embrittlement Testing of Plating Processes and Service Environments 2.3 Aerospace Industries Association Publications Available from Aerospace Industries Association, 1000
27、 Wilson Boulevard, Suite 1700, Arlington, VA 22209-3928, Tel: 703-358-1000, www.aia-aerospace.org. NASM1312-12 Fastener Test Methods, Thickness of Metallic Coatings SAE AMS2460A Page 4 of 14 3. TECHNICAL REQUIREMENTS 3.1 Material 3.1.1 Basis Metal Quality The basis metal (parts) shall be submitted t
28、o the plating processor free from visible defects such as blemishes, prior pitting from corrosion, nicks, scratches, burrs or other geometrical or base metal defects that could be detrimental to the appearance or performance of the plating. The plating processor shall perform such cleaning and plati
29、ng procedures as necessary to yield a deposit that conforms to the specified requirements. 3.1.2 Parts dimensions should be such that, after plating, specified tolerances will be met (See 8.2). 3.1.3 Peening When specified, parts shall be peened prior to plating. Unless otherwise specified, such pee
30、ning shall be accomplished on all surfaces for which the plating is required and on all immediately adjacent surfaces that contain notches, fillets or other abrupt changes of section size (See 8.4.1). Peening shall be performed by or on behalf of the part fabricator, unless specifically delegated to
31、 the plating processor 3.2 Preparation 3.2.1 Stress Relief Treatment Unless otherwise specified, steel parts 34 HRC (ultimate tensile strength 152 ksi 1048 MPa) and higher and that have been machined, ground, cold formed, or cold straightened after heat treatment shall be cleaned to remove surface c
32、ontamination and thermally stress relieved before plating. Acid cleaning shall not be used. See 8.4.2.3. (Residual tensile stresses have been found to be damaging during electrofinishing.) Temperatures to which parts are heated shall be such that maximum stress relief is obtained while still maintai
33、ning hardness of parts within drawing limits. Unless otherwise specified, the following treatment temperatures and times shall be used: 3.2.1.1 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 (1
34、35 C 14) for 5 to 10 hours. 3.2.1.2 For parts having a 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. 3.2.1
35、.3 For peened parts: If stress relief temperatures above 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. 3.2.2 Cleaning The plating shall be applied over a
36、surface free from water breaks. The cleaning procedure shall not produce pitting, intergranular attack, or hydrogen embrittlement of the basis metal and shall preserve dimensional requirements. See 8.4.2. 3.2.3 Electrical Contact Points For parts which are to be plated all over, locations shall be a
37、cceptable to purchaser. For parts which are not to be plated all over, locations shall be in areas on which plating is not required. 3.2.4 Aluminum alloys shall be zincate treated in accordance with ASTM B 253 or other method acceptable to purchaser prior to plating. SAE AMS2460A Page 5 of 14 3.3 Pr
38、ocedure 3.3.1 Parts shall be plated by electrodeposition of chromium plating onto a properly prepared surface. Procedures and operating parameters shall be adequate to meet the properties and quality requirements of this specification. 3.3.2 Underplating Unless otherwise specified, the following app
39、ly: 3.3.2.1 Class 1 plating shall be applied over an intermediate plating of nickel in accordance with AMS2403 or AMS-QQ-N-290 on steel, zinc, and copper alloys. 3.3.2.2 Class 2 plating shall be deposited directly on the basis metal without a preliminary plating of another metal, except parts made f
40、rom maraging steel, or corrosion resistant steel, or aluminum alloy may receive a preliminary deposit of nickel or other suitable metal to a thickness not greater than 0.0002 inch (5 m). 3.3.2.3 Underplate shall not be substituted for any portion of the specified chromium plate thickness. 3.3.3 Plat
41、ing re-start procedures, if used, shall be approved by the cognizant engineering organization. See 4.4.3. 3.3.4 Hydrogen Embrittlement Relief (Baking) Hydrogen embrittlement relief baking applies only to steel alloys unless otherwise specified by the cognizant engineering authority. At the option of
42、 the processor, hydrogen embrittlement relief baking may be performed on other families of alloys. If performed on other alloy families, all hydrogen embrittlement relief baking operations shall be documented. Hydrogen embrittlement relief baking shall be in accordance with AMS2759/9, except as show
43、n in Table 1. Depending on the metallurgical condition of the parts at time of plating (i.e., alloy, hardness, prior heat treatment - carburized, induction hardened, etc.), the cognizant engineering authority may elect to prescribe hydrogen embrittlement relief baking temperatures and times differen
44、t from those shown in Table 1. TABLE 1 - HYDROGEN EMBRITTLEMENT RELIEF (BAKING) REQUIREMENTS (1)Ultimate Tensile Strength Inch/Pound Units Ultimate Tensile Strength SI Units Hardness Time in Hours at 375 oF (191 oC) 160 ksi to 182 ksi, excl. 1103 MPa to 1255 MPa, excl. 36 to 39 HRC 3 182 ksi to 221
45、ksi, excl. 1255 MPa to 1518 MPa, excl. 40 to 45 HRC 8 221 ksi, and higher 1518 MPa, and higher 46 HRC and higher 23 (1) NOTE: All times shown are minimum times. For high strength steels 40 HRC (ultimate tensile strength 182 ksi 1255 MPa) and higher, it may be beneficial, and the processor is permitt
46、ed, to extend the baking time to 23 hours to ensure complete relief from hydrogen embrittlement. 3.4 Properties The plating shall conform to the following requirements: 3.4.1 Thickness Thickness shall be as specified on the drawing, determined in accordance with any of the following methods as appli
47、cable: ASTM B 487, ASTM B 499, ASTM B 504, ASTM B 556, ASTM B 567, ASTM B 568, ASTM B 748, ASTM B 764 or by other method acceptable to the purchaser. NASM1312-12 may be used for thickness measurement of plated fasteners. ASTM B 556 (spot test) may be used for Class 1 plating, when a destructive proc
48、edure is applicable. SAE AMS2460A Page 6 of 14 3.4.1.1 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 specified thickness. Unless otherwise specified, surfaces such as holes, recesses, threads and other areas where a c
49、ontrolled deposit cannot be obtained under normal plating conditions, may be under the specified limit provided they show visual plating coverage. The plate shall be substantially uniform in thickness on significant surfaces except that build-up at exterior corners or edges shall be permitted provided finished drawing dimensions are met. 3.4.1.2 Class 1 Unless otherwise specified, the minimum thi
