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 2010 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/AMS7271J AEROSPACE MATERIAL SPECIFICATION AMS7271 REV. J Issued 1953-06 Reaffirmed 2001-10 Re
5、vised 2010-05 Superseding AMS7271H Rings, Sealing, Butadiene-Acrylonitrile (NBR) Rubber Fuel and Low Temperature Resistant 60 - 70 RATIONALE AMS7271J is a Five Year Review and update of this specification including the addition of a QPL. 1. SCOPE 1.1 Form This specification covers a butadiene-acrylo
6、nitrile (NBR) rubber in the form of molded rings. 1.2 Application These rings have been used typically for sealing at temperatures as low as -67 F (-55 C) where resistance to fuel is required, but usage is not limited to such applications. The cross-section of rings is usually not over 0.275 inch (6
7、.98 mm) in diameter or thickness. 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 i
8、s 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 documents in effect on the da
9、te 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 document has been specified, the
10、last published issue of that document shall apply. SAE AMS7271J Page 2 of 13 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. AMS2470 Anodic Treatment of Alu
11、minum Alloys, Chromic Acid Process AMS2817 Packaging and Identification, Preformed Packings AS291 Surface Texture, Roughness, Waviness and Lay AS568 Aerospace Size Standard for O-Rings AS871 Manufacturing and Inspection Standards for Preformed Packings (O-Rings) AIR851 O-Ring Tension Testing Calcula
12、tions 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 395 Rubber Property - Compression Set ASTM D 412 Vulcanized Rubber and Thermoplastic Elastomers - Tension ASTM D 471 Rubber P
13、roperty - Effects of Liquids ASTM D 573 Rubber Property - Deterioration in an Air Oven ASTM D 792 Specific Gravity (Relative Density) and Density of Plastics by Displacement ASTM D 1414 Rubber - Testing O-Rings ASTM D 2240 Rubber Property - Durometer Hardness 2.3 U.S. Government Publications Availab
14、le from the Document Automation and Production Service (DAPS), Building 4/D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, Tel: 215-697-6257, http:/assist.daps.dla.mil/quicksearch/ AS9491 Bolt, Machine, Hexagon Head, Full Shank, AMS 5731, 0.3125-24, UNJF-3A AS9882 Nut, Plain, Hexagon - Drilled, C
15、admium Plated - UNS G87400, 125 KSI MIN AN960 Washer-Flat 3. TECHNICAL REQUIREMENTS 3.1 Material Shall be a compound, based on a butadiene-acrylonitrile (NBR) elastomer, suitably cured to produce sealing rings meeting the requirements of 3.2. SAE AMS7271J Page 3 of 13 3.2 Properties Rings shall conf
16、orm to the requirements shown in Table 1; tests shall be performed on the rings supplied and, except as otherwise specified herein, in accordance with ASTM D 1414, insofar as practicable. Tensile strength testing is not required on rings which are too small to permit assembly on rollers and are, aft
17、er cutting, too short to permit testing as a single strand. Eliminating testing for tensile strength does not eliminate testing for elongation; elongation test can be made by stretching a ring over a mandrel of a size which will stretch the ring sufficiently to produce the required elongation when f
18、igured on the ID of the ring. Calculations 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“ or equivalent 65 5 ASTM D 2240 3.2.1.2 Tensile Strength, minimum 120
19、0 psi (8.27 MPa) ASTM D 412 3.2.1.3 Elongation, minimum 200% ASTM D 412 3.2.1.4 Corrosion Nil 3.2.1.5 Specific Gravity Preproduction Value 0.02 ASTM D 297 3.2.2 Aromatic and Non-Aromatic Fuel Resistance See 4.6.1 ASTM D 471 3.2.2.1 Volume Change 2.1.1 Aromatic Fuel +40 to +70% 2.1.2 Non-Aromatic Fue
20、l Positive Swell 3.2.2.2 Volume Change, maximum (after immersion in aromatic fuel and oven drying) (based on unimmersed volume) -15% 3.2.2.3 Volume Change, maximum (after reimmersion) (based on unimmersed volume) -5% 3.2.3 Low-Temperature Flexibility See 4.6.2 3.2.3.1 As Received, maximum -58 F (-50
21、 C) 3.2.3.2 After immersion in aromatic fuel and drying, maximum -53 F (-47 C) 3.2.3.3 Elongation Change, maximum -45% 3.2.4 Dry Heat Resistance Temperature: 257 F 5 (125 C 3) Time: 70 hours 0.5 ASTM D 573 3.2.4.1 Hardness Change, Durometer “A“ or equivalent 0 to +15 3.2.4.2 Tensile Strength Change,
22、 maximum -25% 3.2.4.3 Elongation Change, maximum -50% 3.2.4.4 Bend (flat) No cracking or checking 3.2.5 Compression Set Percent of Original Deflection, maximum, for Ring Cross Section Diameter Temperature: 257 F 5 (125 C 3) Time: 70 hours 0.5 ASTM D 395 3.2.5.1 0.066 to 0.110 inch (1.68 to 2.79 mm),
23、 inclusive 85% 3.2.5.2 Over 0.110 inch (2.79 mm) 75% 3.2.6 Simulated Component Test Pass See 4.6.3 3.2.7 Neckdown Tests See 4.6.4 3.2.7.1 Dry Neckdown Test Pass See 4.6.4.1 3.2.7.2 Wet Neckdown Test Pass See 4.6.4.2 SAE AMS7271J Page 4 of 13 3.3 Quality Rings, as received by purchaser, shall be unif
24、orm in quality and condition, smooth, as free from foreign material as commercially practicable, and free from internal imperfections detrimental to usage of the rings. Surface imperfections shall be no greater than permitted by AS871 for minor defects. 3.4 Sizes and Tolerances Shall be as specified
25、 on the drawing. Inspection for conformance to dimensional requirements shall be made in accordance with AS871. Standard sizes are as shown in AS568. 4. QUALITY ASSURANCE PROVISIONS 4.1 Qualification: 4.1.1 Seals that qualify are placed on a Qualified Product List (QPL) maintained by the QPL agency.
26、 To qualify, seals shall meet the tests specified in Table 1, performed in accordance with the provisions of 8.2. 4.1.2 Qualification shall be in accordance with the provisions of 4.1.4 and 4.1.5. 4.1.3 Recertification of qualification is required every three years. Recertification consists of compl
27、ete qualification tests in accordance with the requirements listed in Table 1. 4.1.4 Qualification testing, review of test results, approval, re-approval, and recertification of qualification for QPL listing shall be in accordance with PD 2000 or equivalent and the instructions from the responsible
28、QPL agency. 4.1.5 Seals furnished to this specification will be listed or approved for listing on the qualified products list (QPL) in accordance with the provisions of 8.2 and 8.3. Changes in the product formulation, basic methods of manufacturer, or plant site, for qualified NBR rubber seals liste
29、d or approved for listing on the “QPL”, are not permitted without first notifying the responsible QPL agency to assess the need for requalification and/or revision to the QPL. 4.2 Responsibility for Inspection The vendor of rings shall supply all samples for vendors tests and shall be responsible fo
30、r the performance of all required tests. Purchaser reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that the rings conform to specified requirements. 4.3 Classification of Tests 4.3.1 Acceptance Tests Acceptance Tests for O-rings: Requirements shown in
31、Table 2 are acceptance tests and shall be performed on each lot. Acceptance tests shall be performed on the rings supplied that are suitable for test and in accordance with ASTM D 1414. For all other sizes compression set and specific gravity tests shall be conducted on the end item or a section rem
32、oved 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 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 ins
33、pection but are otherwise expected to meet the physical properties of this specification may be used for specific gravity and compression set testing. SAE AMS7271J Page 5 of 13 4.3.2 Acceptance Tests for All Other Seal Geometries Specific gravity and volume swell (3.2.2) tests shall be conducted on
34、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 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
35、 have not passed visual inspection but are otherwise expected to meet the physical properties of this specification may be used for specific gravity and volume swell testing. TABLE 2 - ACCEPTANCE TESTS Requirement Paragraph Hardness, as received 3.2.1.1 Tensile Strength, as received 3.2.1.2 Elongati
36、on, as received 3.2.1.3 Specific Gravity, as received 3.2.1.5 Volume Change in fuel 3.2.2 Compression Set 3.2.5 4.3.3 Qualification Tests All technical requirements are qualification tests and shall be performed prior to or on the initial shipment of rings to a purchaser, when a change in ingredient
37、s and/or processing requires re-approval as in 4.4.2, and when purchaser deems confirmatory testing to be required. 4.4 Sampling and Testing Shall be as follows: 4.4.1 For Acceptance Tests Sufficient rings shall be selected at random from each lot to perform all required tests; the number of determi
38、nations for each requirement shall be as specified in the applicable test procedure or, if not specified therein, not less than three. 4.4.1.1 A lot shall be all rings of the same size from the same batch of compound processed in one continuous run and presented for vendors inspection at one time, p
39、lus rings as required for the simulated component test when the size used for that test is not part of the lot. 4.4.1.2 A batch shall be the quantity of compound run through a mill or mixer at one time. 4.4.1.3 A statistical sampling plan acceptable to the purchaser may be used in lieu of sampling a
40、s in 4.4.1. 4.4.1.4 Sampling Plan The sample unit shall be one molded part. Acceptance is based on zero defects. Sample size for visual and dimensional requirements shall be as shown in Table 4. SAE AMS7271J Page 6 of 13 TABLE 4 - VISUAL AND DIMENSIONAL INSPECTION Lot Size Sample Size 2 to 8 Entire
41、Lot 9 to 90 8 91 to 150 12 151 to 280 19 281 to 500 21 501 to 1200 27 1201 to 3200 35 3201 to 10 000 38 10 001 to 35 000 46 35 001 to 150 000 56 150 001 and Over 65 4.4.2 For Qualification Tests Shall be from one production batch/lot; AS568 size -214 O-rings shall be used for all testing. 4.5 Approv
42、al 4.5.1 Sample rings shall be approved by purchaser before rings for production use are supplied, unless such approval be waived by purchaser. Results of tests on production rings shall be essentially equivalent to those on the approved sample. 4.5.2 Vendor shall establish, for each size of ring, p
43、arameters for the process control factors which will produce rings meeting the technical requirements of this specification. These shall constitute the approved procedure and shall be used for manufacturing production rings. If necessary to make any change in parameters for process control factors,
44、vendor shall submit for reapproval a statement of the proposed changes in ingredients and/or processing and, when requested, sample rings. Production rings incorporating the revised procedures shall not be shipped prior to receipt of reapproval. 4.5.2.1 Control factors for producing rings include, b
45、ut are not limited to, the following: Compound ingredients or proportions thereof within established limits Sequence of mixing compound ingredients and associated time, temperature, or work input controls Type of mixing equipment Method and equipment for preparing preforms Basic molding procedure (c
46、ompression, transfer, injection) Curing time, temperature, and pressure, maintained within statistically derived control limits Finishing methods Methods of inspection 4.5.2.1.1 Any of the above process control factors for which parameters are considered proprietary by the vendor may be assigned a c
47、ode designation. Each variation in such parameters shall be assigned a modified code designation. SAE AMS7271J Page 7 of 13 4.6 Test Methods 4.6.1 Aromatic and Non-Aromatic Fuel Resistance The specimens shall be tested in accordance with ASTM D 471 and as follows: 4.6.1.1 Immerse separate specimens
48、in ASTM Reference Fuel B and in ASTM Reference Fuel A at 68 to 86 F (20 to 30 C) for 70 hours 0.5; determine volume change immediately after removal from fuel. 4.6.1.2 The specimen from the aromatic fuel immersion of 4.5.1.1 may be allowed to air dry for such time as may suit the testing schedule an
49、d shall then be dried in an oven at 158 F 2 (70 C 1) for 48 hours 0.5, cooled in a desiccator to room temperature, and the volume change determined. 4.6.1.3 Immerse the specimen from 4.5.1.2 in ASTM Reference Fuel A at 68 to 86 F (20 to 30 C) for 5 hours 0.1; determine volume change. 4.6.2 Low-Temperature Flexibility Rings 1.00 inch (25.4 mm) and under in nominal OD shall b
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