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 2008 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: 724-776-4970 (outside USA)
4、 Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org AS2078A AEROSPACE STANDARD Issued 1991-02 Reaffirmed 2007-08 Revised 2008-02 Superseding AS2078 (R) Test Methods, Hose Assemblies, Polytetrafluoroethylene (PTFE) This standard is equivalent to ISO 8829 RATIONALE This
5、 standard is being revised to reflect the current requirements as Section 3 - PTFE Inner Tube Test Methods, Section 4 - Metallic Braided Hose Assembly Test Methods, the addition of Section 5 - Non-Metallic Braided Hose Assembly Test Methods, and the addition of SI equivalent units as applicable. FOR
6、EWORD This standard has been prepared to standardize on the test methods for qualification of polytetrafluoroethylene (PTFE) hose and hose assemblies used in aircraft fluid systems. Compliance with these test methods is necessary for hose and hose assemblies which are used in systems where a malfunc
7、tion could affect the safety of flight. 1. SCOPE AND FIELD OF APPLICATION This SAE Aerospace Standard (AS) describes the test methods for flexible PTFE hose and hose assemblies used in aircraft fluid systems in the pressure and temperature ranges defined in specific procurement specifications. It ap
8、plies to the hose and the hose coupling. The tests and assembly requirements for the connecting end fitting are covered in the procurement specification. This document applies each time that it is referred to in a procurement specification or other definition document. 1.1 Hose Assembly Test Methods
9、 The test methods to be used for testing of hose and hose assemblies shall be defined as follows: a. Section 3 - PTFE Inner Tube Test Methods b. Section 4 - Metallic Braided Hose and Hose Assembly Test Methods c. Section 5 - Non-Metallic Braided Hose and Hose Assembly Test Methods Refer to Appendix
10、A for an index listing of test methods. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS2078A - 2 - 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this documen
11、t to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this docu
12、ment takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or
13、 724-776-4970 (outside USA), www.sae.org. AS603 Impulse Testing of Hydraulic Hose, Tubing and Fitting Assemblies AS1055 Fire Testing of Flexible Hose, Tube Assemblies, Coils, Fittings, and Similar System Components ARP1153 Method for Determining Relative Specific Gravity Polytetrafluoroethylene Tubi
14、ng 2.1.2 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 471 Standard Test Methods for Rubber Property Effects of Liquids ASTM D 792 Standard Test Methods for Density and Specific Gra
15、vity (Relative Density) of Plastics by Displacement ASTM D 1505 Standard Test Methods for Density of Plastics by the Density-Gradient Technique ASTM D 4895 Standard Specification for Polytetraflouroethylene (PTFE) Resin Produced from Dispersion 2.1.3 Military Publications Available from the Document
16、 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/ MIL-PRF-680 Dry Cleaning Solvent MIL-DTL-5624 Turbine Fuel, Aviation, Grade JP4, JP5, JP5/JP8 ST MIL-PRF-7808 Lubricating Oil, Aircraft
17、Turbine Engine, Synthetic Base MIL-F-8815 Filter and Filter Elements, Fluid Pressure, Hydraulic Line, 15 Micron Absolute and 5 Micron Absolute, Type II Systems, General Specification for MIL-C-81302 Cleaning Compound, Solvent, Trichlorotrifluoroethane MIL-PRF-83282 Hydraulic Fluid, Fire Resistant, S
18、ynthetic, Hydrocarbon Base, Aircraft MIL-PRF-87257 Hydraulic Fluid, Fire Resistant, Low Temperature, Synthetic Hydrocarbon Base, Aircraft and Missile Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-S
19、AE AS2078A - 3 - 2.2 Definitions ROOM TEMPERATURE: Temperature in the test laboratory between 60 and 90 F (15.6 and 32.2 C). FIRE SLEEVE: Flame and fire retardant element to protect the hose assembly in a fire zone. Normally tubular which is slipped over the hose assembly and fastened at the hose fi
20、tting, or extruded/molded, normally (silicone) rubber, onto the hose and hose to fitting sealing joint. FIRE CUFF: Flame and fire retardant element, normally (silicone) rubber, either molded, or added and bonded in place, over the hose to fitting sealing joint. ABRASIVE SLEEVE: Material used to resi
21、st mechanical wear between the hose and some other surface. Can be tubular, integrally braided, extruded, or wrapped over the hose. PRESSURE TOLERANCES: The tolerance allowed for all noted pressures. This tolerance shall be as defined in the applicable hose assembly procurement specification. 3. PTF
22、E INNER TUBE TEST METHODS 3.1 Density and Relative Density This test is intended to verify the crystallinity of PTFE inner tubes. The relative density of PTFE tubing shall be measured in accordance with ARP1153. The density of the PTFE tubing shall be measured in accordance with ASTM D 792 or ASTM D
23、 1505. 3.2 Tensile Test and Elongation This test is intended to verify the mechanical properties of the PTFE tubing. 3.2.1 Test Conditions Test specimens shall be conditioned for at least 2 h at room temperature before testing. 3.2.2 Testing Machine Tension tests shall be conducted using a power-dri
24、ven machine which maintains a uniform rate of grip separation at 2 in/min (50 mm/min) and which has a suitable dynamometer and a device for measuring the applied force within 2%. If the capacity range cannot be changed during a test, as in the case of pendulum dynamometers, the applied force at brea
25、k shall be measured within 2%, and the smallest tensile force measured shall be accurate to within 10%. If the dynamometer is of the compensating type for measuring tensile stress directly, means shall be provided to adjust for the cross-sectional area of the specimen. The response of the recorder s
26、hall be sufficiently rapid that the applied force is measured accurately during the extension of the specimen to rupture. If the test machine is not equipped with a recorder, a device shall be provided that indicates after rupture the maximum force applied during extension. Test machines shall be ca
27、pable of measuring elongation in increments of 10%. 3.2.3 Micrometers The micrometer used for measuring flat specimen thickness shall be capable of exerting a pressure of 3.6 psi 0.7 psi (25 kPa 5 kPa), on the specimens and of measuring the thickness to within 0.001 in (0.025 mm). NOTE: Dial microme
28、ters exerting a force of 0.18 lbf 0.034 lbf (0.8 N 0.15 N) force on a circular foot 0.25 in (6.35 mm) in diameter, or 0.045 lbf 0.009 lbf (0.2 N 0.04 N) force on a circular foot 0.125 in (3.2 mm) in diameter conform to this pressure requirement. A micrometer should not be used to measure the thickne
29、ss of specimens narrower in width than the diameter of the foot unless the contact pressure is properly adjusted. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS2078A - 4 - 3.2.4 Calibration o
30、f Testing Machine The testing machine shall be calibrated. If the dynamometer is of the strain-gage type, calibrate the test machine at one or more forces at regular intervals. 3.2.5 Tensile Test Specimens Tensile test specimens shall be as shown in Figure 1. NOTE: Careful maintenance of die cutting
31、 edges is of extreme importance and can be obtained by light daily honing and touching up the cutting edges with jewelers hard honing stones. The condition of the die may be judged by investigating the rupture point on any series of broken specimens. When broken specimens are removed from the clamps
32、 of the testing machine, it is advantageous to pile these specimens and note if there is any tendency to break at or near the same portion of each specimen. Rupture points consistently occurring at the same place may be an indication that the die is dull, nicked, or bent at that particular position.
33、 TR 0.1875 inR 5 mmL0.875 in 0.04 in24 mm 1 mm0.625 in 0.04 in16 mm 1 mm0.1875 in 0.005 in5 mm 0,15 mmTDimensions in inch / mm Thickness = Measured Thickness of Specimen Minimum Tab Length T = 0.3125 in / 8 mm Minimum Length L = 1.50 in / 40 mm FIGURE 1 - TENSILE TEST SPECIMEN 3.2.6 Determination of
34、 Tensile Strength and Elongation Place the specimens in the jaws of the testing machine, using care to adjust the specimen symmetrically in order that the tension will be distributed uniformly over the cross section. Start the machine and note continuously the distance between the jaws, taking care
35、to avoid parallax. At rupture, measure and record the elongation to the nearest 10% on the scale. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS2078A - 5 - 3.2.7 Calculation a. Calculate the
36、tensile strength as follows: Tensile strength (psi or N/mm2) = F/A (Eq. 1) where: F = observed force, in pounds or newtons, required to rupture the specimens A = cross-sectional area in in2or mm2, of the unstretched specimen NOTE: 1 N/mm2= 1 MPa Calculate the elongation as follows: Elongation, % = (
37、L - Lo)/Lox 100 (Eq. 2) where: L = observed distance between the jaws at rupture of the specimen Lo = original distance between the jaws 3.3 Tube Roll and Proof Test This test is intended to verify that there are no flaws in the sintered tube. 3.3.1 Tube Rolling Each tube shall be passed, in a singl
38、e pass, through six sets of metal rollers so that it is subjected to the following sequence of diametral flexings; rollers shall be arranged to prevent inadvertent rotation of the tube. It is assumed that the tube is in a horizontal position and that pressure of the first set of rolls is exerted ver
39、tically; angles given for the final three sets of rolls may be taken as either clockwise or counterclockwise from the vertical diameter of the tube. Roller angles are specified in Table 1. A tolerance of 2 degrees is allowed on each roller angle. The roller gap dimensions are specified in Table 2. R
40、oller gaps shall not be larger than specified in Table 2 for each size. TABLE 1 - ROLLER FUNCTIONS AND ANGLES Phase Type of Action Roller Angle Degree A Flattening 0 B Flattening 90 C Rounding 0 D Flattening 45 E Flattening 135 F Rounding 45 Copyright SAE International Provided by IHS under license
41、with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS2078A - 6 - TABLE 2 - GAP DIMENSIONS FOR ROLLING1 Hose size Inch (DN) Flattening Gap Max 1500 psi (10 500 kPa) Hose Inch (mm) Flattening Gap Max 3000 psi (21 000 kPa) and Higher Hose Inch (mm) Rounding G
42、ap Max 1500 psi (10 500 kPa) Hose Inch (mm) Rounding Gap Max 3000 psi (21 000 kPa) and Higher Hose Inch (mm) 03 (05) 0.203 (5,2) 0.203 (5,2) 0.218 ( 5,5) 0.250 ( 6,4) 04 (06) 0.218 (5,5) 0.281 (7,1) 0.218 ( 5,5) 0.250 ( 6,4) 05 (08) 0.218 (5,5) - 0.250 ( 6,4) - 06 (10) 0.218 (5,5) 0.281 (7,1) 0.312
43、( 7,9) 0.328 ( 8,3) 08 (12) 0.234 (5,9) 0.328 (8,3) 0.375 ( 9,5) 0.469 (11,9) 10 (16) 0.250 (6,4) 0.328 (8,3) 0.500 (12,7) 0.578 (14,7) 12 (20) 0.250 (6,4) 0.328 (8,3) 0.500 (12,7) 0.688 (17,5) 14 (22) - 0.328 (8.3) - 0.765 (19.4) 16 (25) 0.250 (6,4) 0.328 (8,3) 0.750 (19,1) 0.828 (21,0) 20 (32) 0.3
44、12 (7,9) 0.438 (11,1) 0.875 (22,2) 1.000 (25,4) 24 (40) 0.375 (9,5) - 1.250 (31,8) - 18000 psi (56 000 kPa) odd size high pressure hose assembly callout will utilize lower even hose size except for -03 (DN05) size. (Example: -07 (DN11) assy = -06 (DN10) size. 3.3.2 Proof Test Following the roll test
45、, the tube shall be held for not less than 2 min at pressures as specified in Table 3 using water, air, or nitrogen as the test medium. TABLE 3 - PROOF PRESSURES OF HOSE INNER TUBE1Size Inch (DN) Proof Pressure - Minimum 1500 psi (10 500 kPa) Hose psi (kPa) Proof Pressure - Minimum 3000 psi (21 000
46、kPa) and Higher Hose psi (kPa) 03 (05) 390 (2690) 480 (3310) 04 (06) 360 (2480) 380 (2620) 05 (08) 290 (2000) - 06 (10) 230 (1590) 280 (1930) 08 (12) 180 (1240) 220 (1520) 10 (16) 170 (1170) 170 (1170) 12 (20) 140 ( 965) 130 ( 890) 14 (23) - 110 ( 758) 16 (25) 90 ( 621) 95 ( 660) 20 (32) 65 ( 448) 9
47、5 ( 660) 24 (40) 45 ( 310) - 18000 psi (56 000 kPa) odd size high pressure hose assembly callout will utilize lower even hose size except for -03 (DN05) size. (Example: -07 (DN11) assy = -06 (DN10) hose.) Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction
48、 or networking permitted without license from IHS-,-,-SAE AS2078A - 7 - 3.4 Electrical Conductivity Test This test is intended to verify that the hose inner tube is sufficiently conductive to prevent buildup of excessive electrostatic charge which could cause arcing and create pin holes in the tube. 3.4.1 The test specimen shall be a 14 in (350 mm) length of PTFE hose tube without braid. The inner surface of the tube shall be washed first with solvent per MIL-PRF-680, if required, then/or with isopropyl alcohol
