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 2016 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/AMS2485L AEROSPACE MATERIAL SPECIFICATION AMS2485 REV. L Issued 1948-05 Revised 2
5、016-02 Superseding AMS2485K Coating, Black Oxide RATIONALE AMS2485L results from a five year review and update of this specification. NOTICE ORDERING INFORMATION: The following information shall be provided to the plating processor by the purchaser. Purchase order shall specify not less than the fol
6、lowing: AMS2485L 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 3.1.2 Special features, geometry, or processing present on parts that requires special attention by the processo
7、r Optional: Periodic testing frequency (4.2.2) and sample quantity (4.3.2) Quantity of pieces to be coated 1. SCOPE 1.1 Purpose This specification covers the requirements for black oxide coatings on parts. 1.2 Application This coating has been used typically to improve the anti-chafing and anti-fric
8、tion properties of carbon and low-alloy steel parts, particularly for sliding or bearing surfaces, by providing a finish coating that retains an oil film, but usage is not limited to such applications. SAE INTERNATIONAL AMS2485L Page 2 of 6 1.3 Safety - Hazardous Materials While the materials, metho
9、ds, applications, 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
10、 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 documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein.
11、 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 document has been specified, the last published issue of that document shall apply. 2.1 ASTM Publications Available from AST
12、M International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM G46 Examination and Evaluation of Pitting Corrosion 3. TECHNICAL REQUIREMENTS 3.1 Preparation 3.1.1 The coating shall be applied to part surfaces free from water-breaks. The
13、 cleaning procedure shall not produce pitting or intergranular attack of the basis metal and shall preserve dimensional requirements 3.1.2 Steel parts having a hardness of 36 HRC and higher and that are machined, ground, cold worked or straightened shall be cleaned to remove surface contamination an
14、d thermally stress relieved before coating. Temperatures to which parts are heated shall be such that maximum 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: 3.1.2.1 F
15、or parts, excluding nitrided parts, having a hardness of 55 HRC and above, including carburized and induction hardened parts, stress relieve at 275 F 25 F (135 C 14 C) for a minimum of 4 hours. 3.1.2.2 For parts having a hardness less than 55 HRC, stress relieve at 375 F 25 F (191 C 14 C) for a mini
16、mum 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 Procedure 3.2.1 The cleaned parts, while still wet, shall be immersed in one or more boiling aqueous alkali oxidizing baths for tim
17、es and at temperatures which will produce coatings meeting the requirements of 3.3 and 3.4 (see 8.3). 3.2.2 Coated parts shall be washed thoroughly in running water to remove all traces of processing solution and salts. Parts shall not be allowed to dry during the entire sequence of operations until
18、 completion of this rinse. 3.2.3 Parts shall be thoroughly dried unless a water-displacing oil is used in 3.2.4, in which case complete drying may be omitted. 3.2.4 Parts shall be dipped in a suitable corrosion-preventative oil. SAE INTERNATIONAL AMS2485L Page 3 of 6 3.3 Properties Coated parts shal
19、l conform to the following requirements: 3.3.1 Smut Test Coatings on parts before oiling as in 3.2.4, or on oiled parts after degreasing, shall show no indications of reddish-brown or green smut when wiped with a clean, white cloth. 3.3.2 Dimensional Change When determined using a micrometer accurat
20、e to 0.0001 inch (2.5 mm), no dimensional change shall result from processing. 3.3.3 Oxalic Acid Spot Test The coating, prior to application of corrosion preventative oil, shall be tested as follows. Clean, dry coated parts or specimens of the same composition and heat treat condition as the parts a
21、nd processed with the parts represented shall be handled with clean gloves. Each sample shall have deposited three drops of a 5% (approximately) solution of oxalic acid on a flat surface. Permit the accompanying reaction to continue for not less than eight minutes, followed by rinsing in cool water
22、and drying. When examined, the area which was directly under the acid test solution drops shall exhibit a black or dark brown center with a light border. Areas under the drop, which exhibit a gray center and lighter border are marginal coatings and are not acceptable. 3.3.4 Surface and Intergranular
23、 Attack The cleaning and coating process shall not result in any surface pitting, as determined by ASTM G46 and intergranular attack, determined on metallographically-prepared cross-sections examined unetched at 400X to 500X magnification. 3.4 Quality Except as otherwise specified herein, the coatin
24、g on polished surfaces shall be a uniformly lustrous black. Coating on other surfaces shall be black or dark gray in color, uniform on areas of equivalent surface roughness. Coating on all types of surfaces shall be free of spots of red oxide or an overall reddish-brown color but an overall reddish-
25、brown cast on a basically black color is permissible. Coating shall be continuous, smooth, dense, and adherent and shall not rub off under any conditions incident to normal handling or storage. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The processor of coated parts shall supp
26、ly all 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 sp
27、ecified requirements. 4.2 Classification of Tests 4.2.1 Acceptance Tests Smut test (3.3.1), oxalic acid spot test (3.3.3), and quality (3.4) are acceptance tests and shall be performed on parts, or specimens representing parts when permitted by cognizant engineering organization, from each lot. 4.2.
28、2 Periodic Tests Surface and intergranular attack (3.3.4) when parts 36 HRC or higher are processed are periodic tests and shall be performed monthly unless frequency of testing is specified by the purchaser. Tests of cleaning and coating baths are periodic tests and shall be performed at a frequenc
29、y established by the processor unless frequency of testing is specified by the purchaser (see 4.4.3 and 8.2). SAE INTERNATIONAL AMS2485L Page 4 of 6 4.2.2.1 Periodic Testing may be suspended in any test period (e.g., month or quarter) when parts are not processed. 4.2.3 Preproduction Tests All prope
30、rty verification tests (section 3.3) are preproduction tests and shall be performed prior to production or on the initial shipment of coated parts to a purchaser, and when the cognizant engineering organization requires confirmatory testing. 4.3 Sampling and testing shall be not less than the follow
31、ing; a lot shall be all parts made of the same material, heat treated to the same hardness or tensile strength level, processed in the same solution(s) in not longer than eight consecutive hours, and presented for processors inspection at one time. Parts for tests shall be selected randomly from all
32、 parts in the lot. 4.3.1 Acceptance tests shall be as shown in Table 1. Table 1 - Sampling for acceptance tests Lot Size Quality Smut Test Oxalic Acid Spot Test Up to 7 All All or 3* 1 7 to 15 7 4 1 16 to 40 10 4 1 41 to 110 15 5 2 111 to 300 25 6 3 301 to 500 35 7 4 Over 500 50 8 5 *Whichever is le
33、ss 4.3.2 Periodic Tests Sample quantity shall be selected at the discretion of the processor unless otherwise specified by the purchaser. As a minimum, one sample shall be tested for all periodic tests. 4.3.3 Sample Configuration When coated parts are of such configuration or size as to not be readi
34、ly adaptable to specified tests or when nondestructive testing is not practical on actual parts, or when it is not economically acceptable to perform destructive tests on actual parts, separate specimens made from 4340 steel, 260 280 ksi (51 53 HRC) representing all classes of alloys and heat treat
35、conditions as the parts, cleaned and coated with the parts may be used. 4.4 Approval 4.4.1 The process and control factors, a preproduction 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
36、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 organization for process reapproval unless the change is approved by the cognizant en
37、gineering 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 plated by the revised procedure shall not be shipped prior to receipt of reapproval. 4.4.3 Controls factors sh
38、all include, but not be limited to the following: Cleaning method Material designation and supplier Corrosion preventive oil used Periodic test plan for cleaning and processing solutions (see 8.2). SAE INTERNATIONAL AMS2485L Page 5 of 6 4.5 Reports The processor of coated parts shall furnish with ea
39、ch 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 include the purchase order number, lot identification number, AMS2485L, part number, and quantity. 4.
40、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, recoated and retested. Alternatively, all parts in the lot may be inspected for the nonconforming attribute, and the nonconforming parts may be stripped, recoated
41、, 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
42、.2 If any periodic test fails to meet specified test requirements, the process is nonconforming. No additional parts shall be coated until the process is corrected and new specimens are coated and tested. Results of all tests shall be recorded and, when requested, reported. Purchaser shall be notifi
43、ed of all parts coated since the last acceptable periodic test. 5. PREPARATION FOR DELIVERY 5.1 Coated parts shall be handled and packaged to ensure that the required properties of the coating are preserved. 5.2 Packages of coated parts shall be prepared for shipment in accordance with commercial pr
44、actice and in compliance with applicable rules and regulations pertaining to the handling, packaging, and transportation of the parts to ensure carrier acceptance and safe delivery. 6. ACKNOWLEDGMENT Processor shall mention AMS2485L in all quotations and when acknowledging purchase orders. 7. REJECT
45、IONS Coated parts on which the coating does not conform to this specification, or to modifications authorized by purchaser, will be subject to rejection. 8. NOTES 8.1 Revision Indicator A change bar (|) located in the left margin is for the convenience of the user in locating areas where technical r
46、evisions, not editorial changes, have been made to the previous issue of a specification. An (R) symbol to the left of the document title indicates a complete revision of the specification. Change bars and (R) are not used in original publications, nor in specifications that contain editorial change
47、s only. 8.2 ARP4992, Periodic Test Plan for Process Solutions, is recommended to satisfy requirements for control of processing solutions. 8.3 No specific composition is given for the black oxide processing bath. The intensity of the black color is dependent on the time of immersion, the temperature
48、 of the bath, and the concentrations of the bath ingredients. Typical black oxide baths consist of sodium hydroxide with additions of oxidizers and inhibitors, the composition being adjusted to maintain a selected boiling temperature in the range of 250 to 310 F (121 to 154 C). Immersion times range
49、 from 5 to 60 minutes. Composition is generally adjusted to maintain the selected boiling temperature. In some cases, a two tank treatment is used, each with different processing conditions, but each essentially as described above. 8.4 The appearance of the coating is affected by the composition, condition, and surface finish of the basis material. SAE INTERNATIONAL AMS2485L Page 6 of 6 8.5 Preca
