1、AEROSPACE MATERIAL SPECIFICATION AMS7257 REV. E Issued 1985-04 Reaffirmed 1998-08 Revised 2014-09 Superseding AMS7257D Perfluorocarbon (FFKM) Engine Oil, Fuel and Hydraulic Fluid Resistant 70 to 80 Hardness For High Temperature Seals in Engine Oil Systems, Fuel Systems and Hydraulic Systems RATIONAL
2、E This document requires revision to correct f ormatting errors contained in AMS7257D that are causing confusion in Manufacturer Acceptance Tests. 1. SCOPE 1.1 Form This specification covers a Perfluorocarbon (FFKM) rubber in the form of molded rings, compression seals, o-ring cord, and molded-in-pl
3、ace gaskets for aeronautical and aerospace applications. 1.2 Application These products have resistance to a variety of fluids, but usage is not limited to such applications. Each application should be considered separately. This perfluorocarbon (FFKM) has a typical service temperature range of +5 t
4、o 554 F (-15 to 290 C). 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 which may be involved in such use. It is the sole
5、 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 documents in effect on the date of the
6、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 document has been specified, the last publi
7、shed issue of that document shall apply. _ 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, includ
8、ing any patent infringement arising therefrom, 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 2014 SAE Internation
9、al All rights reserved. No part of this 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 (i
10、nside USA and Canada) Tel: +1 724-776-4970 (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/AMS7257E SAE INTERNATIONAL AMS7257E Page
11、 2 of 9 2.1 SAE Publications Available from SAE 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. AIR851 O-Ring Tension Testing Calculations AMS2817 Packaging and Identification, Preformed Packings
12、AMS3085 Reference for Testing AS5780 HPC Class (Polyol) resistant material ARP3050 Suitable Test Sizes for O-ring Specifications AS568 Aerospace Size Standard for O-Rings AS5752 Aerospace Visual Inspection Standard for Elastomeric Sealing Elements Other than O-rings AS1241 Fire Resistant Phosphate E
13、ster Hydraulic Fluid for Aircraft 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 D 297 Rubber Products - Chemical Analysis ASTM D 395 Rubber Property - Compression Set ASTM D 471 R
14、ubber Property - Effects of Liquids ASTM D 573 Rubber Property - Deterioration in an Air Oven ASTM D 1329 Rubber Property - Retraction at Lower Temperatures (TR Test) ASTM D 1414 Rubber Property- Testing O-Rings ASTM D 2240 Rubber Property - Durometer Hardness 2.3 ISO Publications Available from Int
15、ernational Organization for Standardization, 1, rue de Varembe, Case postale 56, CH-1211 Geneva 20, Switzerland, Tel: +41-22-749-01-11, www.iso.org ISO 3601-1 Fluid Power Systems O-rings Part 1: Inside Diameters, Cross-sections, Tolerances and Designation Codes ISO 3601-3 Fluid Power Systems O-rings
16、 Part 3: Quality Acceptance Criteria 2.4 PRI Publications Available from Performance Review Institute, 161 Thorn Hill Road, Warrrendale, PA 15086-7257, Tel: 724-772-1616, www.pri-network.org. PD2000 Procedures for an Industry Qualified Product Management Process PD2102 Aerospace Quality Assurance, P
17、roduct Standards, Qualification Procedure, Elastomeric Seal SAE INTERNATIONAL AMS7257E Page 3 of 9 3. TECHNICAL REQUIREMENTS 3.1 Material Shall be prepared from ingredients as necessary to achieve the requirements detailed in this standard and shall be a compound, based on a perfluoroelastomer (FFKM
18、), suitably cured to produce product meeting the requirements of 3.2. Material used shall be based on 100% virgin perfluoroelastomer (FFKM). No reprocessed or non-perfluoroelastomer (FFKM) polymer is acceptable. 3.2 Properties The product shall conform to the requirements shown in Table 1; Calculati
19、ons of tensile strength and elongation may be made in accordance with AIR851. TABLE 1 PROPERTIES Paragraph Property Requirements Test Method 3.2.1 As Received 3.2.1.1 Hardness, Durometer “A” 75 5 ASTM D 2240 3.2.1.2 Tensile Strength, min 1500 psi (10.3 MPa) ASTM D 1414 3.2.1.3 Elongation, min 120% A
20、STM D 1414 3.2.1.4 Specific Gravity Preproduction Value 0.02 ASTM D 297 Hydrostatic method 3.2.1.5 Low Temperature Resistance ASTM D 1329 Temperature Retraction (TR10), max +41 F (+5 C) Use test slab as Specimen 3.2.2 Aromatic Fuel Resistance ASTM D 471 3.2.2.1 Hardness Change, Durometer “A” -5 to +
21、5 ASTM Reference Fuel B 73 F 5 (23 C 2) 70 hours 0.5 3.2.2.2 Tensile Strength Change, max -20% 3.2.2.3 Elongation Change, max -15% 3.2.2.4 Volume Change, max 0 to +5% 3.2.3 Turbine Engine Oil Resistance ASTM D 471 3.2.3.1 Hardness Change, Durometer “A” -5 to +5 AMS3085 392 F 5 (200 C 2) 70 hours 0.5
22、 3.2.3.2 Tensile Strength Change, max -10% 3.2.3.3 Elongation Change, max -15% 3.2.3.4 Volume Change, max 0 to +5% 3.2.3.5 Compression Set, max 25% ASTM D 395 Method B AMS3085 392 F 5 (200 C 2) 70 hours 0.5 3.2.4 Hydraulic Fluid Resistance ASTM D 471 AS1241 Type IV Class 1 or 2 257 F 5 (125 C 2) 70
23、hours 0.5 3.2.4.1 Hardness Change, Durometer “A” -15 to 0 3.2.4.2 Tensile Strength Change, max -40% 3.2.4.3 Elongation Change, max -15% 3.2.4.4 Volume Change, max 0 to +15% SAE INTERNATIONAL AMS7257E Page 4 of 9 TABLE 1 PROPERTIES (CONTINUED) 3.2.5 Dry Heat Resistance ASTM D 573 554 F 5 (290 C 2) 70
24、 hours 0.5 3.2.5.1 Hardness Change, Durometer “A” -5 to +5 3.2.5.2 Tensile Strength Change, max -20% 3.2.5.3 Elongation Change, max -5% 3.2.5.4 Weight Loss, max 5% 4.4.1 3.2.6 Compression Set, max 40% ASTM D 395 Method B 446 F 5 (230 C 2) 70 hours 0.5 3.2.7 Long Term Compression Set, max 55% ASTM D
25、395 Method B 446 F 5 (230 C 2) 336 hours 0.5 3.3 Quality Product, as received by purchaser, shall be uniform in quality and condition, smooth, as free from foreign material as commercially practicable, and free from internal imperfections detrimental to usage of the seals. Surface imperfections shal
26、l be no greater than permitted by ISO3601-3 Grade CS or AS5752 type 1 or 2 as applicable. 3.4 Dimensions and Tolerances Dimensions and tolerances shall be as specified in the parts standard, drawing or purchase document. If not specified, o-rings standard sizes and tolerances are shown in AS568. The
27、 procedures outlined in Annex B of ISO 3601-1 shall be followed for dimensional inspection. 3.5 Part Numbers Shall consist of the following 1. The specification number AMS7257 2. A dash followed by the appropriate dash number from AS568 Example 1 Example 2 AMS7257 014 AMS7257 121 3.6 Toxicological F
28、ormulations The material shall have no adverse effects on the health of personnel when used for its intended purpose in accordance with manufacturers instructions and with appropriate handling procedures. 3.7 Qualification Products sold to this specification shall be listed on the PRI qualified prod
29、ucts list, (QPL). The qualified products list shall be in accordance with PD2000 (See 8.2). This QPL requirement shall be in effect one year after the date of issuance of this document. 3.7.1 Qualification shall be reapproved every three years in accordance with PD2000, PD2102 and the instructions f
30、rom the Performance Review Institute. Testing shall be in accordance with 4.2.2. SAE INTERNATIONAL AMS7257E Page 5 of 9 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The manufacturer of the product shall be responsible for performance of all required tests. Purchaser reserves the
31、 right to sample and perform any testing deemed necessary to ensure that the product conforms to the AMS requirements. 4.1.1 Manufacturer Shall be on the current PRI Qualified Manufacturers List (QML). 4.2 Classification of Tests 4.2.1 Acceptance Tests Acceptance Tests for o-rings: Requirements show
32、n in Table 2 are acceptance tests and shall be performed on each lot. Acceptance Tests for o-rings: Requirements shown in Table 3 are acceptance tests and shall be performed on each batch. Acceptance tests shall be performed on the rings supplied and in accordance with ASTM D 1414. O-ring sizes that
33、 are suitable for testing are shown in ARP3050. For all other sizes compression set and specific gravity tests shall be conducted on the end item or a section removed from the end item. Testing performed on a size -214 O-ring of the same batch and state of cure shall satisfy the remaining acceptance
34、 tests as long as the testing was performed within 90 days of the manufacture of the subject lot. Note: O-rings from the same lot which have not passed visual inspection but are otherwise expected to meet the physical properties of this specification may be used for specific gravity and compression
35、set testing Acceptance tests for all other seal geometries: Specific gravity and volume swell (3.2.1.4, 3.2.2.4, 3.2.3.4, and 3.2.4.4) tests shall be conducted on the end item or a section removed from the end item. Testing performed on a size -214 O-ring of the same batch and state of cure shall sa
36、tisfy the remaining acceptance tests as long as the testing was performed within 90 days of the manufacture of the subject lot. Note: Parts from the same lot which have not passed visual inspection but are otherwise expected to meet the physical properties of this specification may be used for speci
37、fic gravity and volume swell testing. TABLE 2 ACCEPTANCE TESTS Requirement Paragraph Hardness 3.2.1.1 Specific Gravity 3.2.1.4 Quality 3.3 Sizes and Tolerances 3.4 TABLE 3 BATCH ACCEPTANCE TESTS Requirement Paragraph Hardness 3.2.1.1 Tensile Strength 3.2.1.2 Elongation 3.2.1.3 Specific Gravity 3.2.1
38、.4 Compression Set 3.2.6 4.2.1.1 Lot A quantity of one size of product processed and packaged as one production entity from a batch. 4.2.1.2 Batch A batch shall be the quantity of compound run through a mill or mixer at one time. Excluded from the definition is blending of batches of previously comp
39、ounded material. SAE INTERNATIONAL AMS7257E Page 6 of 9 4.2.1.3 Random Sampling The method shall be as specified in the parts standard, drawing or purchase document. If not specified, product shall be taken at random from each lot to perform all the required acceptance tests. The number of test iter
40、ations for each requirement shall be specified in the applicable test procedure. 4.2.1.4 Sample Shall be end product whenever possible. Suitable test size for o-rings shall be determined by ARP3050. When impossible to test the end product, AS568 size -214 o-rings with the same state of cure as the p
41、roduction part shall be tested. 4.2.2 Qualification Tests All technical requirements shall be performed prior to the initial shipment of the product to a purchaser. When a change in ingredients and/or processing requires reapproval, when purchaser deems confirmatory testing to be required, and for r
42、eapproval of qualification per 3.7.1 4.2.2.1 Sample: Shall be from a production batch/lot; AS568 size -214 o-rings shall be used for all testing. 4.2.2.2 Testing Shall be in accordance with PD2000 and PD2102. Verification tests shall consist of tests listed in Table 3 plus long term compression set
43、(3.2.7). Testing for qualification reapproval shall be all technical requirements (no verification tests are required). 4.2.2.3 Report The supplier of the product shall make a qualification test report available. This report shall include AMS number, manufacturers identification and product designat
44、ion, batch/lot number, date of manufacture and the results of all qualification tests. 4.3 Inspection 4.3.1 End of Process Inspection Shall be as specified in the parts standard, drawing or purchase document. If not specified, shall be as follows: Prior to inspection, mold flash shall be removed fro
45、m the parts in such a manner that they conform to the requirements specified herein. Each individual part (100%) shall be visually inspected according to ISO 3601-3, Grade CS or AS5752 as applicable, using 1X magnification. The entire surface of the part shall be manually inspected. 4.3.2 Final Insp
46、ection Shall be as specified in the parts standard, drawing or purchase document. If not specified, shall be as follows: The parts shall be visually inspected according to ISO 3601-3, Grade CS or AS5752, as applicable, using 2X magnification. The entire surface of the part shall be manually inspecte
47、d. The sample size for final inspection shall be in accordance with ANSI/ASQ Z1.4 single sampling plan inspection level II with an AQL 1.0 except that the acceptance number shall be zero. The sample unit shall be one part. The manufacturer of the parts shall be responsible for the required inspectio
48、ns. The purchaser reserves the right to sample and perform any confirmatory inspection deemed necessary to ensure that the parts conform to the specified requirements. Prior to inspection, mold flash shall be removed from the parts in such a manner that they conform to the requirements specified her
49、ein. Each individual part (100%) shall be visually inspected according to ISO 3601-3, Grade CS (S for Silicones) or AS5752 as applicable, using 2X magnification. The entire surface of the part shall be manually inspected. SAE INTERNATIONAL AMS7257E Page 7 of 9 4.4 Test Methods 4.4.1 Weight Loss Tests The weight loss test sha
