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/AS25427 AEROSPACE STANDARD AS25427 Issued 2004-04 Reaffirmed 2015-07 Coupling Ass
5、embly, Hydraulic, Self-Sealing, Quick Disconnect FSC 4730 RATIONALE AS25427 has been reaffirmed to comply with the SAE five-year review policy. NOTICE This document has been taken directly from U.S. Military Specification MIL-C-25427A, Amendment 1 and contains only minor editorial and format changes
6、 required to bring it into conformance with the publishing requirements of SAE Technical Standards. The initial release of this document is intended to replace MIL-C-25427A, Amendment 1. Any part numbers established by the original specification remain unchanged. The original military specification
7、was adopted as an SAE Standard under the provisions of the SAE Technical Standards Board (TSB) Rules and Regulations (TSB 001) pertaining to accelerated adoption of government specifications and standards. TSB rules provide for (a) the publication of portions of unrevised government specifications a
8、nd standards without consensus voting at the SAE committee level, and (b) the use of the existing government specification or standard format. Under Department of Defense Policies and Procedures, any qualification requirements and associated qualified products lists are mandatory for DoD contracts.
9、Any requirement relating to Qualified Products Lists (QPLs) has not been adopted by SAE and is not part of this technical report. SAE INTERNATIONAL AS25427 Page 2 of 17 1. SCOPE: 1.1 Scope: This specification covers the detail requirements for aircraft hydraulic self-sealing quick disconnect couplin
10、gs, for use in types I and II hydraulic systems (-65F to +275F temperature range) as defined by Specification MIL-H-5440. 1.2 Classification: Hydraulic self-sealing, quick disconnect couplings shall be one of the following classes, as specified (see 6.2): Class 600600-pounds per square inch (PSI) ra
11、ted pressure furnished only in 1-1/4 inch tube size. Class 30003,000-PSI rated pressure furnished only in 1/4-, 3/8-, 1/2-, 5/9-, 3/4-, and 1-inch sizes. 2. APPLICABLE DOCUMENTS: 2.1 The following documents, of the issue in effect on date of invitation for bids, form a part of this specification to
12、the extent specified herein: SPECIFICATIONS MILITARY MIL-E-5272 Environmental Testing, Aeronautical and Associated Equipment, General Specification for. MIL-H-5440 Hydraulic Systems: Design, Installation and Test of Aircraft, (General Specification for). MIL-F-5509 Fittings; Fluid Connections. MIL-H
13、-5606 Hydraulic Fluid, Petroleum Base, Aircraft and Ordnance. MIL-H-8775 Hydraulic Systems Components, Aircraft, General Specification for. MIL-F-18280 Fittings, Flareless, Fluid Connection. SAE INTERNATIONAL AS25427 Page 3 of 17 2.1 (Continued): STANDARDS MILITARY MIL-STD-130 Identification Marking
14、 of U. S. Military Property. MS24333 Coupling Assembly, Hydraulic, Self-Sealing, Quick Disconnect, Flared Fitting to Internal Thread Boss. MS24334 Coupling Assembly, Hydraulic, Self-Sealing, Flareless Fitting to Internal Thread Boss. MS24335 Flange, Bulkhead Mounting, Hydraulic, Self-Sealing Couplin
15、g. MS28774 Retainer, Packing Backup, Single Turn, Tetrafluoroethylene. MS28775 Packing, Preformed, Hydraulic, +275F, (“O“ Ring). MS28782 Retainer, Packing, Back-Up, Teflon. MS28783 Ring, Gasket, Back-Up, Teflon. AIR FORCE-NAVY AERONAUTICAL AND10064 Fittings, Installation of Flared Tube, Straight Thr
16、eaded Connectors. (Copies of specifications, standards, drawings, and publications required by contractors in connection with specific procurement functions should be obtained from the procuring activity or as directed by the contracting officer.) 3. REQUIREMENTS: 3.1 Qualification: The couplings fu
17、rnished under this specification shall be a product which has been tested, and has passed the qualification tests specified herein, and has been listed on or approved for listing on the applicable Qualified Products List. SAE INTERNATIONAL AS25427 Page 4 of 17 3.2 General specification: The requirem
18、ents of Specification MIL-H-8775 apply as requirements of this specification, with the exceptions and additions specified herein. When the two specifications conflict, this specification shall govern. 3.3 Materials: The coupling shall be constructed of materials that will not change the composition
19、of or be adversely affected by hydraulic fluid conforming to Specification MIL-H-5606. (See 4.5.2.) 3.4 Design and construction: The configuration, dimensions, and other details of design of the couplings shall conform to the applicable MS standard. Coupling nuts, or other coupling devices, shall be
20、 a part of the hose attaching coupling-half assembly. When coupled, the coupling shall be such that it will permit fluid flow in either direction in accordance with the rated flow and pressure drop as specified in table I. Flow shall not be blocked under surge conditions. TABLE I. Rated flow and pre
21、ssure drop Dash No. Equivalenttube size Rate flow GPMPressure drop PSI (max) 4 6 8 10 12 16 20 1/4 3/8 1/2 5/8 3/4 1 1-1/4 1.2 3.5 6.0 10.5 16.0 29.0 45.0 8 8 8 8 8 8 8 3.4.1 Temperature range: Couplings shall be designed to operate throughout the temperature range of -65F to +275F. (See 4.6.1.) 3.4
22、.2 Sealing and fluid loss: The couplings shall, when uncoupled, seal the ends of the disconnected lines at the point of disconnection and shall not permit external leakage during any phase of coupling or uncoupling. Fluid loss is specified in table II is not considered to be external leakage. Both h
23、alves of the coupling shall seal fluid under both low and high pressures when tested as specified in 4.6.3. 3.4.3 Seals: Only Standard MS28775 O-ring packings, and Standards MS28774, MS28782, and MS28788 Teflon backup rings shall be used. SAE INTERNATIONAL AS25427 Page 5 of 17 3.4.4 Air inclusion: A
24、ir inclusion, as determined by calculation of volume of air that may be displaced to the inside of the coupling during the coupling operation, shall not exceed the values specified in table II when tested as specified in 4.6.10. TABLE II. Air inclusion and fluid loss Dash No. Equivalenttube size Air
25、 inclusioncubic inches (max) Average fluid loss per operating cycle cubic centimeter (max) 4 6 8 10 12 16 20 1/4 3/8 1/2 5/8 3/4 1 1-1/4 0.05 0.12 0.20 0.50 0.70 0.90 1.20 0.50 1.30 2.20 5.80 8.20 9.00 11.80 3.4.5 Operation: The coupling shall be so designed that it can be coupled and uncoupled with
26、 one hand without the use of tools. Coupling and uncoupling operations shall be possible with 60-PSI static pressure applied to both halves of the coupling. Inadvertent uncoupling shall not occur under 20G maximum loading. It shall be possible to determine by visual inspection that the coupling is c
27、ompletely coupled and locked. In addition, couplings shall provide a touch indication for determining whether the coupling is locked or unlocked. Couplings shall not have any partially coupled unlocked positions in which the coupling can remain stable and permit fluid flow. Couplings shall be couple
28、d with a single simple motion. (See 4.6.9.) 3.4.6 Flange: A removable bulkhead flange for fastening the coupling to a bulkhead shall be provided, as required by the MS standard, for use on the bulkhead mounting end of the coupling. The flange shall be in accordance with Standard MS24335. This flange
29、 shall withstand 1.5 times the maximum steel tubing wrench torque as specified by Standard AND10064 for a given tube size coupling when tested as specified in 4.6.13. 3.5 Interchangeability: Couplings shall be interchangeable as an assembly. It shall be impossible to interconnect different tube size
30、s. SAE INTERNATIONAL AS25427 Page 6 of 17 3.6 Performance: The self-sealing couplings furnished under this specification shall perform satisfactorily when subjected to the tests specified in section 4 headed as follows: (a) Examination of product (See Specification MIL-H-8775). (b) Extreme temperatu
31、re functioning (4.6.1). (c) Proof pressure (4.6.2) (d) Leakage (4.6.3) (e) Pressure drop (4.6.4) (f) Vacuum (4.6.5) (g) Surge flow (4.6.6) (h) Impulse and vibration (4.6.7) (i) Endurance (4.6.8) (j) Manual operation (4.6.9) (k) Air inclusion (4.6.10) (l) Impact (4.6.11) (m) Burst pressure (4.6.12) (
32、n) Flange strength (4.6.13) 3.7 Color: The tube connection ends of the coupling shall be colored in accordance with Specification MIL-F-5509 and MIL-F-18280, as applicable. The uncoupling device shall be colored orange. SAE INTERNATIONAL AS25427 Page 7 of 17 3.8 Identification of product: The coupli
33、ng shall be marked for identification in accordance with Standard MIL-STD-130. In addition, each coupling shall be permanently marked with the MS and manufacturers part numbers and the manufacturers name or trademark as required on Standard MS24333 or MS24334. Each manufacturer shall identify all co
34、uplings by an identification letter. This letter will follow the MS number, but precede the size dash number; i.e., MS24333-x-size. The identification letter will be assigned when a manufacturers first coupling is approved and will be used on all couplings manufactured by the same source. 3.9 Workma
35、nship: Workmanship shall be of the quality necessary to produce couplings free from all defects which would affect proper functioning in service. 4. QUALITY ASSURANCE PROVISIONS: 4.1 Inspection responsibility: The supplier is responsible for the performance of all inspection requirements as specifie
36、d herein. Except as otherwise specified, the supplier may utilize his own or any other inspection facilities and services acceptable to the Government. Inspection records of the examination and tests shall be kept complete and available to the Government as specified in the contract or order. The Go
37、vernment reserves the right to perform any of the inspections set forth in the specification where such inspections are deemed necessary to assure supplies and services conform to prescribed requirements. 4.2 Classification of tests: The sampling, inspection, and testing of couplings shall be in acc
38、ordance with Specification MIL-H-8775 and as specified herein. The tests shall consist of qualification tests and acceptance tests (4.3 and 4.4, respectively). SAE INTERNATIONAL AS25427 Page 8 of 17 4.3 Qualification tests: 4.3.1 The qualification tests shall consist of the following tests and shall
39、 be conducted in the following order. All tests, except Examination of product, are described under 4.6. (a) Examination of product (See Specification MIL-H-8775). (b) Extreme temperature functioning (4.6.1). (c) Proof pressure (4.6.2) (d) Leakage (4.6.3) (e) Pressure drop (4.6.4) (f) Vacuum (4.6.5)
40、 (g) Surge flow (4.6.6) (h) Impulse and vibration (4.6.7) (i) Endurance (4.6.8) (j) Manual operation (4.6.9) (k) Air inclusion (4.6.10) (l) Impact (4.6.11) (m) Proof pressure (repeat) (4.6.2) (n) Burst pressure (4.6.12) (o) Flange strength (4.6.13) SAE INTERNATIONAL AS25427 Page 9 of 17 4.4 Acceptan
41、ce tests: The acceptance tests shall consist of the following tests. All tests, except Examination of product, are described under 4.6. (a) Examination of product (See Specification MIL-H-8775) (b) Proof pressure (4.6.2) (c) Leakage at low pressure (4.6.3.1) 4.5 Test conditions: 4.5.1 Temperatures:
42、Except where otherwise specified, the tests of this specification shall be conducted at a room temperature of 70 to 90F and with a fluid temperature of 70 to 110F, as measured within 12 inches of the test sample. The actual temperature of the fluid during the tests shall be recorded in the test repo
43、rts. 4.5.2 Immersion: All couplings shall be immersed continuously in hydraulic fluid for a period of 72 hours at a fluid temperature of 275 5F, prior to conducting the qualification tests (see 4.3) specified herein. All internal parts of the coupling shall be in contact with the fluid during this i
44、mmersion. After the 72 hours soak period, the coupling shall be subjected to the next test immediately or remain in the fluid at normal room temperatures until such test. 4.6 Test methods: 4.6.1 Extreme temperature functioning: The couplings shall withstand the following tests without malfunctioning
45、 or leakage in excess of the values specified herein. (See 3.4.1.) 4.6.1.1 High temperature: After immersion (4.5.2), but before being uncoupled, the coupling shall be connected to a 30-inch static head of hydraulic fluid and subjected to a temperature of 275 5 F for a period of 6 hours. There shall
46、 be no measurable leakage from the connected coupling during the 6-hour period. At the end of this time, the coupling shall be cooled to 140 5F and at least five cycles of coupling and uncoupling shall be completed. There shall be no binding during any cycle of disconnection and connection. The temp
47、erature of the uncoupled halves shall be raised to 225 5F and shall be subjected to the leakage at low pressure test (4.6.3.1) and then subjected to the leakage at high pressure test (4.6.3.2). SAE INTERNATIONAL AS25427 Page 10 of 17 4.6.1.2 Low temperature: After completion of the high temperature
48、tests (4.6.1.1), the couplings shall be connected to a 30-inch static head of hydraulic fluid, and subjected to a temperature not warmer than -65F for a period of 4 hours after stabilization. There shall be no measurable leakage from the connected coupling during this period. At the end of this peri
49、od, at least five cycles of coupling and uncoupling shall be completed. There shall be no binding during any cycle of disconnection and connection. The uncoupled halves shall be subjected to the leakage at low pressure test (4.6.3.1) and then subjected to the leakage at high pressure test (4.6.3.2). It will be satisfactory for the temperature to rise to -40F during this process. 4.6.1.3 Rapid warmup: T