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 entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, 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.QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8512 FAX: (724) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1998 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001STANDARDSubmitted for recognition as an American National StandardJ1131R
4、EV.AUG1998Issued 1976-01Revised 1998-08Superseding J1131 MAR97Performance Requirements for SAE J844 Nonmetallic Tubing andFitting Assemblies Used in Automotive Air Brake Systems1. ScopeThis SAE Standard is intended to establish uniform methods of testing SAE J844 tubing and fittingassemblies as used
5、 in automotive air brake systems.This document also establishes minimum qualifications for tensile and pressure capabilities, vibrationaldurability under cyclic temperatures, serviceability, and fitting compatibility requirements. The specific testsand performance criteria applicable to the tubing a
6、re set forth in SAE J844.NOTEThe test values contained in this document are for test purposes only. For environmental andusage limitations see SAE J844. FittingsA type of fitting for use with SAE J844 nonmetallictubing is included in SAE J246; however, it is not intended to restrict or preclude the
7、use of otherdesigns of fittings that comply with this document.2. References2.1 Applicable PublicationsThe following publications form a part of this specification to the extent specifiedherein. Unless otherwise indicated, the latest issue of SAE publications shall apply.2.1.1 SAE PUBLICATIONSAvaila
8、ble from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J246Spherical and Flanged Sleeve (Compression) Tube FittingsSAE J844Nonmetallic Air Brake System Tubing3. Tension Tests3.1 DescriptionBoth hot and cold tensile tests shall be conducted with different unaged assemblies (fittingsattac
9、hed within 30 days of test date). Tests consist of subjecting the assembly to increasing tension load in asuitable testing machine until the specified force values or elongation percentages are obtained.3.2 ApparatusA tension testing machine with suitable indicating device shall be used for the tens
10、ion test. Thefixtures for holding the test specimens shall be arranged so that the tubing and fittings have a straight centerline corresponding to the direction of the machine pull. The lower part of the fixture shall be equipped with acontainer of sufficient dimensions to submerge the required leng
11、th of tubing in water. A means of heating thewater to boiling shall be provided.SAE J1131 Revised AUG1998-2-3.3 Test SpecimensObtain tubing specimens from current production stock and cut to a length sufficient toobtain 152 mm 0.625 mm (6 in 0.25 in) of tubing between end fittings after assembly. As
12、semble fittings tothe tubing using the manufacturers recommendations.3.4 Procedure3.4.1 HOT PULLPlace the test specimen in the tensile machine with the lower fitting and 102 mm (4in) of tubing submerged below the surface of the boiling distilled water such that the outsidediameter is exposed to the
13、water. Continue boiling for 5 min min. Apply load at a rate of pull of 25 mm(1 in) per min.3.4.2 CONDITIONED PULL TESTSoak test specimen in air at 40 C 3 C (40 F 5 F) for 30 min min,normalize at room temperature, and submerge in boiling water for 15 min. Repeat for a total of four completecycles. Al
14、low the test specimen to normalize at room temperature for 30 min. Conduct the tensile test within30 min after the normalizing period while at ambient temperature of 24 C 3 C (75 F 5 F). Apply loadat a rate of pull of 25 mm (1 in) per min.3.5 RequirementsThe test specimen shall elongate 50%, that is
15、 152 mm (6 in) increased to 229 mm (9 in), orshall withstand the load shown in Table 1, without causing separation from the fitting.4. Vibration Test4.1 DescriptionThis test is designed to evaluate the effects of vibration under varying ambient temperatures ona tubing and fitting assembly. Leakage
16、rate is used to gage acceptability.4.2 ApparatusEquipment capable of vibrating one end of the test specimen at 600 cpm through 12.7 mm(0.5in) displacement in a plane perpendicular to the tube while the other end is held rigid. The distancebetween the static and vibrating heads is to be such that whe
17、n the assembly is displaced 0.5 in, no parallel pullto the longitudinal axis of the assembly will occur. The equipment must be capable of controlling the ambientair temperature between 40 C 3 C (40 F 5 F) and 104 C 3 C (220 F 5 F) and of applying827kPa 69 kPa (120 psig 10 psig) dry air to the test l
18、ines. A mass flow meter capable of determining airleakage shall be provided.4.3 Test SpecimensCut tubing specimens to a length sufficient to obtain 457 mm (18 in) between fittings afterassembly. Assemble identical fittings to the tubing using the manufacturers recommendations. Fittingattaching nuts
19、are not permitted to be retightened during the test.TABLE 1REQUIREMENTSNominalTubingODmm(1)1. For reference only.NominalTubingODinTensileLoadNTensileLoadlb3.2 1/8 67 154.0 5/32 178 404.8 3/16 178 406.4 1/4 222 507.9 5/16 334 759.5 3/8 667 15012.7 1/2 890 20015.9 5/8 1446 32519.0 3/4 1557 350+0.6250.
20、0+0.250.0 +0.50.0+0.50.0SAE J1131 Revised AUG1998-3-4.4 ProcedureAllowing 12.7 mm (0.5 in) slack, mount the lines straight in the vibration machine. Oscillate oneend of the lines at 600 cycles per min 20 cycles per min through a total stroke of 12.7 mm (0.5 in) for a totalof 1 000 000 cycles, while
21、maintaining an internal pressure of 827 kPa 69 kPa (120 psig 10 psig)using dry air. Starting at 104 C 3 C (220 F 5 F), vary the ambient air temperature from 104 C 3 C(220 F 5 F) to 40 C 3 C (40 F 5 F) at 250 000 vibration cycle intervals approximately 7 h intervals).Using a mass flow meter observe f
22、or fitting leakage during and after the test. Check nut tightness aftercompleting the test.4.5 RequirementsThe test specimen is considered a failure if leakage exceeds 50 cm3/min at 40 C 3 C(40 F 5 F) or 25 cm3/min at 21 C 3 C (70 F 5 F). The fitting is considered a failure if the attachingnut becom
23、es loose. This is defined as follows:1. Record the initial tightening torque.2. At the conclusion of the test, attempt to tighten the nut further by applying 20% of the initial tighteningtorque in the tightening direction. Do not apply a higher torque and do not apply any torque or force inthe loose
24、ning direction.3. If the nut moves at all under the 20% torque, it shall be defined as a loose nut and failure of the test.Record the movement in degrees to reach 20%.5. Proof and Burst Pressure Test5.1 DescriptionThis test is intended to evaluate fitting retention at proof pressure (50% of minimum
25、burst) andat minimum burst pressure as listed in the latest issue of SAE J844.5.2 ApparatusThe test apparatus consists of a suitable source of hydraulic pressure and the necessary gagesand piping.5.3 Test SpecimenCut tubing specimens to obtain 305 mm (12 in) between fittings after assembly. Assemble
26、fittings to the tubing using the manufacturers recommendations.5.4 ProcedurePlug one end of the test specimen and mount in the apparatus with the end unrestrained. Applyproof pressure at room temperature, 24 C 3 C (75 F 5 F) to the test specimen and hold for 30 s.Increase pressure at a constant rate
27、 so as to reach the specified minimum burst pressure within a time periodof 3 to 15 s.5.5 RequirementsFittings shall not separate from the tubing nor shall the assembly visibly leak at less thanspecified minimum burst pressure.6. Serviceability Test6.1 DescriptionThis test is intended to evaluate th
28、e effects of repeated assembly and disassembly of a tubingand fitting assembly. Leakage rate is used to gage acceptability.6.2 ApparatusThe test apparatus consists of a suitable source of pneumatic pressure and the necessary gagesand piping. A mass flow meter capable of determining air leakage shall
29、 be provided.6.3 Test SpecimensCut tubing specimens to obtain 305 mm (12 in) between fittings after assembly. Assemblefittings to the tubing using manufacturers recommendations.6.4 ProcedureThe tubing and fitting connections shall be disassembled and reassembled for a minimum of fivetimes. After the
30、 fifth reassembly, pressurize the test specimens with air to 827 kPa 69 kPa (120 psig 10psig) at room temperature, 24 C 3 C (75 F 5 F), and check for leakage.6.5 RequirementsLeakage rate must not exceed 25 cm3/min.+50 0000.0SAE J1131 Revised AUG1998-4-7. Fitting Compatibility Test7.1 DescriptionThis
31、 test is intended to evaluate the effects of high and low temperatures on fitting performance.7.2 ApparatusThe test apparatus consists of a suitable source of hydraulic pressure, 3103 kPa 69 kPa(450psig 10 psig), and necessary gages and piping in environmental test chambers at 93 C 3 C (200 F 5F) an
32、d 40 C 3 C (40 F 5 F).7.3 Test SpecimensCut tubing specimens to obtain 305 mm (12 in) between fittings after assembly. Assemblefittings to the tubing using manufacturers recommendations.7.4 ProcedureFill test specimens with hydraulic fluid and subject to 93 C 3 C (200 F 5 F) andatmospheric pressure
33、for 24 h h then apply internal pressure of 3103 kPa 69 kPa (450 psig 10 psig)for 5 min while maintaining temperature of 93 C 3 C (200 F 5 F). Reduce to atmospheric pressure andpermit test specimens to return to room temperature; then subject test specimens to 40 C 3 C (40 F 5 F) and atmospheric pres
34、sure for 24 h. Apply internal pressure of 3103 kPa 69 kPa (450 psig 10 psig)for 5 min min while maintaining temperature of 40 C 3 C (40 F 5 F).7.5 RequirementsTubing shall not rupture or disconnect from the fittings.PREPARED BY THE SAE FLUID CONDUCTORS AND CONNECTORS TECHNICAL COMMITTEE SC4AIR BRAKE
35、 TUBING AND TUBE FITTINGS+10.0+0.50.0SAE J1131 Revised AUG1998RationaleThere was a change to 3.4.1.Relationship of SAE Standard to ISO StandardNot applicable.ApplicationThis SAE Standard is intended to establish uniform methods of testing SAE J844 tubing andfitting assemblies as used in automotive a
36、ir brake systems.This document also establishes minimum qualifications for tensile and pressure capabilities, vibrationaldurability under cyclic temperatures, serviceability, and fitting compatibility requirements. The specifictests and performance criteria applicable to the tubing are set forth in
37、SAE J844.NOTEThe test values contained in this document are for test purposes only. For environmentaland usage limitations see SAE J844. FittingsA type of fitting for use with SAE J844nonmetallic tubing is included in SAE J246, however, it is not intended to restrict or precludethe use of other desi
38、gns of fittings that comply with this document.Reference SectionSAE J246Spherical and Flanged Sleeve (Compression) Tube FittingsSAE J844Nonmetallic Air Brake System TubingDeveloped by the SAE Fluid Conductors and Connectors Technical Committee SC4Air Brake Tubing and Tube FittingsSponsored by the SAE Fluid Conductors and Connectors Technical Committee
