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 revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2015 SAE International All rights reserved. No part of this p
3、ublication 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: +1 724-776-497
4、0 (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/AMS2481K AEROSPACE MATERIAL SPECIFICATION AMS2481 REV. K Issued 1946-11 Reaffirme
5、d 2006-04 Revised 2015-07 Superseding AMS2481J Phosphate Treatment Antichafing RATIONALE AMS2481K revises Stress Relief Treatment (3.1.1) and Hydrogen Embrittlement (3.3.2), and is a Five Year Review and update of this specification. NOTICE ORDERING INFORMATION: The following information shall be pr
6、ovided to the plating processor by the purchaser. 1. Purchase order shall specify not less than the following: AMS2481K Basis metal to be treated Tensile strength or hardness of the basis metal Pretreatment stress relief to be performed by processor (time and temperature) if different from 3.1.1 Spe
7、cial features, geometry, or processing present on parts that requires special attention by the processor Hydrogen embrittlement relief to be performed by the processor if different from 3.3.2 Quantity of pieces to be treated 2. Parts manufacturing operations such as heat treating, forming, joining a
8、nd media finishing can affect the condition of the substrate for coating, or if performed after coating, 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 specif
9、ication. 1. SCOPE 1.1 Form This specification covers the requirements for a manganese phosphate coating on ferrous alloys. 1.2 Application This process has been used typically to produce a coating that will minimize chafing of contacting steel surfaces and retain an oil film, but usage is not limite
10、d to such applications. SAE INTERNATIONAL AMS2481K Page 2 of 6 1.3 Safety Hazardous Materials While the materials, methods, applications, and processes described or referenced in this specification may involve the use of hazardous materials, this specification does not address the hazards that may b
11、e 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 precautionary measures to ensure the health and safety of all personnel involved. 2. APPLICABLE DOCUMENTS The issue of the following d
12、ocuments 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. When the referenced document has been cancelled and no superseding docum
13、ent 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 +1 724-776-4970 (outside USA), www.sae.org. AMS2750 Pyrometry AMS2759/
14、9 Hydrogen Embrittlement Relief (Baking) of Steel Parts AS2390 Chemical Process Test Specimen Material 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.astm.org. ASTM F519 Test Method for Mechanica
15、l Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments 3. TECHNICAL REQUIREMENTS 3.1 Preparation 3.1.1 Stress Relief Treatment 3.1.1.1 All steel parts having a hardness of 40 HRC and above and that are machined, ground, cold formed or cold straightened after heat t
16、reatment shall be cleaned to remove surface contamination and thermally stress relieved before preparation for coating. (Residual tensile stresses have been found to be damaging during coating.) Furnaces used for stress relief shall be controlled per AMS2750; the minimum requirements shall be Class
17、5, with 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 times shall be used: 3.1.1.1.1 For parts, excludin
18、g 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. 3.1.1.1.2 For parts having a hardness less than 55 HRC, and for nitrided parts, stress relieve at 375 F 25 (191 C 14) for a minimum of 4
19、hours. Higher temperatures shall be used only when specified or approved by the cognizant engineering organization. 3.1.1.1.3 For Peened Parts If stress relief temperatures above 400 F (191 C) are elected, the stress relieve shall be performed prior to peening or the cognizant engineering organizati
20、on shall be consulted and shall approve the stress relief temperature. SAE INTERNATIONAL AMS2481K Page 3 of 6 3.1.2 The phosphate coating shall be applied over a surface free from waterbreaks. The cleaning procedure shall not produce pitting or intergranular attack of the basis metal and shall prese
21、rve dimensional requirements. 3.2 Procedure Parts shall be coated by immersing in a balanced manganese acid phosphating solution containing a suitable accelerating agent. The solution shall be maintained at the proper temperature and parts shall be held in contact with the solution for sufficient ti
22、me to form a uniform, insoluble, crystalline manganese phosphate coating meeting the requirements of 3.4. Parts shall then be immediately rinsed in cold, running water. 3.3 Post Treatment 3.3.1 Post Treatment After rinsing, parts shall be immersed in hot water (See 8.6). Parts shall be thoroughly dr
23、ied unless a water-displacing oil is used for protection of parts in which case, drying may be omitted. Dried parts shall be oiled with a suitable corrosion-inhibiting oil. 3.3.1.1 The application of a water displacing oil or other corrosion inhibiting oil shall follow the hydrogen embrittlement rel
24、ief bake (3.3.2), if baking is required. 3.3.2 Hydrogen Embrittlement After phosphate coating treatment of steel parts having a hardness of 40 HRC or higher shall be in accordance with AMS2759/9, except that parts shall be baked at 210 to 225 F (99 to 107 C) for 8 hours. 3.4 Properties The coating s
25、hall conform to the following requirements: 3.4.1 Appearance Coated parts shall have a uniform, usually grayish-black, finely-crystalline appearance prior to post-treatment. 3.4.2 The coating process after baking shall not cause hydrogen embrittlement in steel parts 40 HRC and over determined in acc
26、ordance with 4.3.4 unless a different specimen type and/or method is specified by the cognizant engineering organization. 3.4.3 Phosphate Coating Weight Unless otherwise specified, shall be 1500 mg/ft2minimum, determined using the differential weight method in accordance with the following relations
27、hip, using equation 1. (Eq. 1) Stripping of coating shall be accomplished using a nominal 5% chromic acid solution at 165 F 10 (74 C 6) or by a room temperature solution of 180 grams of sodium hydroxide and 90 grams of sodium cyanide per liter of water. Repeat the stripping operation until no furthe
28、r weight loss is found. 3.5 Quality Surfaces of treated parts, as received by purchaser, shall be uniform in texture and appearance. Powdery areas, excessive buildup, and darkening of corners and edges are not acceptable. Coating WeightCoated Specimen Weight Stripped Specimen WeightTotal Coated Area
29、-=SAE INTERNATIONAL AMS2481K Page 4 of 6 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 tested, such parts shall be supplied by p
30、urchaser. The cognizant engineering organization reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that processing conforms to the specified requirements. 4.2 Classification of Tests 4.2.1 Acceptance Tests Appearance (3.4.1) and quality (3.5) are accepta
31、nce tests and shall be performed on parts, or specimens representing parts when permitted herein, each lot (See 4.3.3). 4.2.2 Periodic Tests Coating weight (3.4.3) is a periodic test and shall be performed at least monthly unless frequency of testing is specified by the cognizant engineering organiz
32、ation. Hydrogen embrittlement (3.4.2) is a periodic test and shall be performed at least once in each month that steel parts 40 HRC and over are coated unless frequency of testing is specified by the cognizant engineering organization. Tests of cleaning and coating solutions are periodic tests and s
33、hall be performed at a frequency established by the processor unless frequency of testing is specified by the cognizant engineering organization (See 4.4.3 and 8.5). 4.2.3 Preproduction Tests All property verification tests (Section 3.4) are preproduction tests and shall be performed prior to or on
34、the initial shipment of coated parts to a purchaser and when the cognizant engineering organization deems confirmatory testing to be required. 4.3 Sampling for Testing 4.3.1 Acceptance Tests Acceptance test samples shall be randomly selected from all parts in the lot. A lot shall be all parts of the
35、 same part number, processed in a continuous series of operations (3.1 through 3.3), in not longer than 8 consecutive hours, and presented for processors inspection at one time. Unless the cognizant engineering organization provides a sampling plan, the minimum number of samples shall be as shown in
36、 Table 1. Table 1 - Acceptance test sampling Number of Parts in Lot Appearance and Quality Up to 6 All or 3* 7 to 15 7 16 to 40 10 41 to 110 15 111 to 300 25 301 to 500 35 501 to 700 50 701 to 1200 75 Over 1200 125 *Whichever is less SAE INTERNATIONAL AMS2481K Page 5 of 6 4.3.2 Periodic Tests Sample
37、 quantity shall be one unless otherwise specified by the cognizant engineering organization. For hydrogen embrittlement, sample quantity shall be as specified in ASTM F519 unless otherwise specified by the cognizant engineering organization. 4.3.3 Sample Configuration Separate test specimens may be
38、used under any one of the following circumstances: The parts are of such configuration or size as to be not readily adaptable to specified tests, nondestructive testing is not practical on actual parts, or it is not economically acceptable to perform destructive tests on actual parts. Acceptance tes
39、t specimens shall be made of the same generic class of alloy as the parts, established in accordance with AS2390, distributed within the lot, cleaned, coated, and post-treated with the parts represented. The size of the test specimens shall be 1 x 4 inches (25 x 102 mm) minimum. 4.3.4 Hydrogen Embri
40、ttlement Test Test shall be in accordance with the requirements of ASTM F519 Type 1a.1 using round notched specimens, unless a different specimen is specified by the cognizant engineering organization, stressed in tension under constant load. Coating shall meet the requirements of this specification
41、 on specimen surfaces and shall be visible at the root of the notch. 4.4 Approval 4.4.1 The process and control procedures, a preproduction sample coated part, or both, whichever is specified, shall be approved by the cognizant engineering organization before production parts are supplied. When auth
42、orized by the cognizant engineering organization, preproduction test specimens may be substituted for a preproduction sample part. 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
43、 be performed and the results submitted to the cognizant engineering organization for process reapproval unless the change is approved by the cognizant engineering organization. A significant change is one that, in the judgment of the cognizant engineering organization, would affect properties or pe
44、rformance of the parts. 4.4.3 Control factors shall include, but not be limited to, the following: Immersion time Surface preparation and cleaning procedures Phosphating solution composition and composition control limits Phosphating solution temperature limits and controls Post treatment solution c
45、ontrol limits and procedures Hydrogen embrittlement relief bake time and temperature Corrosion inhibiting oil Stripping procedure, if used Periodic test plan for cleaning and processing solutions (See 8.5). 4.5 Reports The processor of coated parts shall furnish with each shipment a report stating t
46、hat the parts have been processed and tested in accordance with the requirements of this specification and that coated parts conform to the acceptance test requirements. This report shall include the purchase order number, lot number, AMS2481K, part number, and quantity. 4.6 Resampling and Retesting
47、 SAE INTERNATIONAL AMS2481K Page 6 of 6 4.6.1 If any acceptance test fails to meet specified test requirements, parts in that lot may be stripped, recoated as defined herein, and tested. Alternatively, all parts in the lot may be inspected for the nonconforming attribute and the nonconforming parts
48、may be stripped, recoated as defined herein, and retested. 4.6.1.1 When stripping is performed, the method shall be acceptable to the cognizant engineering organization and shall not roughen, pit, or embrittle the basis metal or adversely affect part dimensions. When parts have been stripped and recoated, the purchaser shall be informed. 4.6.2 If any periodic test fails to meet specified requirements, the process is nonconforming; no additional parts shall be processed until the process is corrected and new parts or specimens are coated and tested. Results of
