1、Designation: D2532 16D2532 17Standard Test Method forViscosity and Viscosity Change After Standing at LowTemperature of Aircraft Turbine Lubricants1This standard is issued under the fixed designation D2532; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope
3、*1.1 This test method covers the determination of the kinematic viscosity of aircraft turbine lubricants at low temperature, andthe percent change of viscosity after a 3 h and a 72 h standing period at low temperature.1.1.1 The range of kinematic viscosities covered by this test method is from 7700
4、mm2/s to 14 000 mm2/s at 40 C and from7000 mm2/s to 17 500 mm2/s at 51 C. The precision has only been determined for those materials, kinematic viscosity ranges,and temperatures as shown in the precision section. Kinematic viscosities and percent change of viscosity may be measured andreported at ot
5、her temperatures and other thermal soak period intervals as agreed by the contracting parties.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.2.1 The SI unit used in this test method for Kinematic Viscosity is mm2/s. For
6、 user reference, 1 mm2/s = 10-6 m2/s = 1 cSt.1.3 WarningMercury has been designated by many regulatory agencies as a hazardous material that can cause centralnervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Cautionshould be taken
7、when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet(MSDS) for details and EPAs websitehttp:/www.epa.gov/mercury/faq.htmfor additional information. Users should be awarethat selling mercury and/or mercury containing products into your state or
8、country may be prohibited by law.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitatio
9、ns prior to use. For specific hazard statements, see Section 7.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations
10、 issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)D446 Specifications and Operating Instructions for Glass Capi
11、llary Kinematic ViscometersD6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and LubricantsE1 Specification for ASTM Liquid-in-Glass ThermometersE563 Practice for Preparation and Use of an Ice-Point Bath as a Reference TemperatureE644 Test Met
12、hods for Testing Industrial Resistance ThermometersE1137 Specification for Industrial Platinum Resistance ThermometersE1750 Guide for Use of Water Triple Point CellsE2593 Guide for Accuracy Verification of Industrial Platinum Resistance ThermometersE2877 Guide for Digital Contact Thermometers1 This
13、test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved Dec. 1, 2016May 1, 2017. Published January 2017May 2017. Originally approved in 1966. Last
14、 previous edition approved in 20142016 asD2532 14.D2532 16. DOI: 10.1520/D2532-16.10.1520/D2532-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Docu
15、ment Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM r
16、ecommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box
17、 C700, West Conshohocken, PA 19428-2959. United States12.2 Other Documents:MIL-PRF-7808 Lubricating Oil, Aircraft Turbine Engine, Synthetic Base3MIL-PRF-23699 Lubricating Oil, Aircraft Turbine Engine, Synthetic Base, NATO Code Number O-15633. Terminology3.1 Definitions:3.1.1 digital contact thermome
18、ter (DCT), nanan electronic device consisting of a digital display and associated temperaturesensing probe.3.1.1.1 DiscussionThis device consists of a temperature sensor connected to a measuring instrument; this instrument measures the temperature-dependent quantity of the sensor, computes the tempe
19、rature from the measured quantity, and provides a digital output. This digitaloutput goes to a digital display and/or recording device that may be internal or external to the device. These devices are sometimesreferred to as “digital thermometers.”3.1.1.2 DiscussionPET is an acronym for portable ele
20、ctronic thermometers, a subset of digital contact thermometers (DCT).4. Summary of Test Method4.1 Kinematic viscosity and percent change is determined at low temperature using apparatus defined in Test Method D445 andSpecifications D446 at time intervals of 3 h and 72 h following an initial measurem
21、ent at 35 min.5. Significance and Use5.1 Aircraft turbine lubricants, upon standing at low temperatures for prolonged periods of time, may show an increase inkinematic viscosity. This increase may cause lubrication problems in aircraft engines. Thus, this test method is used to ensure thatthe kinema
22、tic viscosity does not exceed the maximum kinematic viscosity in certain specifications for aircraft turbine lubricants.6. Apparatus6.1 Viscometers, drying tubes, low-temperature bath, thermometer, timer, secondary viscosity standard, filter, and cleaningsupplies are described in detail in Test Meth
23、od D445.6.2 ViscometerThe viscometer shall meet the requirements of Test Method D445 and Specifications D446 and be of the typein which the sample can be rerun without cleaning the viscometer. Suitable holders should be used. For convenience it isrecommended that the viscometer size be chosen to kee
24、p the efflux time between 200 s and 1000 s.NOTE 1Consult Specifications D446 regarding calibration constant correction for the actual test temperature when using Specifications D446viscometers that are not suspended level types.6.3 Drying TubesFit the viscometer openings with drying tubes filled wit
25、h indicating silica gel, using cotton at top and bottomto hold the loosely packed desiccant in place. Provide a cross-connection on the viscometer side of the drying tubes (which canbe closed by a pinch clamp or stopcock while liquid is being drawn into the efflux bulb) so that the restriction to ai
26、r flow will notcause error. Replace the silica gel when a lavender color is noticeable.6.4 Viscosity Temperature BathThe constant-temperature bath must be capable of holding several viscometers at once. It musthave adequate stirring of the liquid medium (Note 2) and balance between heat losses such
27、that the bath temperature can bemaintained at the required temperature 60.03 C.NOTE 2Isopropanol or other clear, low-freezing point liquid may be used as a bath liquid.6.5 Temperature Measuring DeviceUse either a digital contact thermometer as described in 6.5.2 with equal or better accuracyor a cal
28、ibrated ASTM Kinematic Viscosity Test Thermometer such as 73C (40 C) or 74C or 43C (51 C) conforming to therequirements as prescribed in Specification E1 which have an accuracy after correction of 60.03 C or better. The ASTM 74Cthermometer has a specification between 55.4 C and 52.6 C but is availab
29、le from some suppliers with the scale expanded tocover 51 C. The 43C thermometer is only graduated in 0.1 C increments so interpretation at midpoints between the lines maybe required.6.5.1 When using liquid-in-glass thermometers, use a magnifying device to read the thermometer to the nearest 15 divi
30、sion (forexample, 0.02 C on thermometers graduated in 0.1 C increments) to ensure that the required test temperature and temperaturecontrol capabilities are met.3 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dod
31、ssp.daps.dla.mil.D2532 1726.5.1.1 Check the thermometers ice point at least annually using an ice bath or a constant temperature bath against a referencethermometer. If the corrected temperature reading error is greater than the temperature tolerance, then the thermometer must berecalibrated.6.5.2 W
32、hen using a digital contact thermometer (DCT), the following requirements shall apply:Criteria Minimum RequirementsDCT E2877 Class ADisplay resolution 0.01 C, recommended 0.001 CDisplay accuracy 30 mK (0.03 C) for combined probe andsensorSensor type RTD, such as a PRT or thermistorDrift less than 10
33、 mK (0.01 C) per yearResponse time less than or equal to 6 s as defined in Speci-fication E1137Linearity 10 mK over range of intended useCalibration Report The DCT shall have a report of temperaturecalibration traceable to a national calibrationor metrology standards body issued by acompetent calibr
34、ation laboratory with demon-strated competency in temperature calibra-tion. An ISO 17025 accredited laboratory withtemperature calibration in its accreditationscope would meet this requirement.Calibration Data The calibration report shall include at least 3calibration temperatures at least 5 C apart
35、which are appropriate for its intended use.6.5.2.1 For a constant temperature bath employed, the DCT probe shall be immersed by more than its minimum immersiondepth in a constant temperature bath so that the center of the probes sensing region is at the same level as the lower half of theworking cap
36、illary provided the probes minimum immersion depth is met and is no less than indicated on the calibration certificate.The end of the probe sheath shall not extend past the bottom of the viscometer. It is preferable for the center of the sensing elementto be located at the same level as the lower ha
37、lf of the working capillary as long as the minimum immersion requirements are met.NOTE 3With respect to DCT probe immersion depth, a procedure is available in Test Methods E644, Section 7 (Minimum Immersion Length Test),for determining the minimum depth. With respect to an ice bath, Practice E563 pr
38、ovides guidance on the preparation of an ice bath, however variancefrom the specific steps is permitted provided preparation is consistent as it is being used to track change in calibration.6.5.2.2 Verify the DCT calibration at least annually. The probe shall be recalibrated when the check value dif
39、fers by more than0.01 C from the last probe calibration. Verification can be accomplished with the use of a water triple point cell, an ice bath, orother suitable constant temperature device which has a known temperature value of suitable precision. See Practice E563, GuideE1750, and Guide E2593 for
40、 more information regarding checking calibrations.6.5.2.3 In the case of constant temperature baths used in instruments for automatic viscosity determinations, the user is tocontact the instrument manufacturer for the correct DCT that has performance equivalence to that described here.6.6 Timing Dev
41、iceUse any timing device, spring-wound or digital, that is capable of taking readings with a discrimination of0.1 s or better and has an accuracy within 60.07 % (see Annex A3 of Test Method D445) of the reading when tested over theminimum and maximum intervals of expected flow times.6.6.1 Timing dev
42、ices powered by alternating electric current may be used if the current frequency is controlled to an accuracyof 0.05 % or better. Alternating currents, as provided by some public power systems, are intermittently rather than continuouslycontrolled. When used to actuate electrical timing devices, su
43、ch control can cause large errors in kinematic viscosity flow timemeasurements.6.7 Secondary Viscosity Standards.7. Procedure for Cleaning Viscometers and Filter Screen7.1 Apply air pressure or suction to the viscometer to remove any previous test specimen. Allow the viscometer to drain for 5min.7.1
44、.1 Wash the viscometer four times, inside and out, with fresh toluene (WarningFlammable) using suction as required.Allow the viscometer to drain.7.1.2 Wash the viscometer four times, inside and out, with acetone, and allow to drain for 5 min. Then dry with vacuum suction.7.2 If organic or other depo
45、sits are visible in the viscometer, clean the viscometer thoroughly by filling it completely with glasscleaning solution for several hours to remove residual traces of organic deposits.Allow to drain for 5 min. It is essential that strongalkaline cleaning solutions are not used as changes in the vis
46、cometer calibration can occur.7.2.1 Rinse viscometer inside and out with distilled water until all traces of the cleaning solution are completely removed.Allowto drain for 5 min.7.2.2 Dry with filtered dry air, a vacuum line, or in an oven at approximately 100 C for approximately 30 min until all tr
47、acesof water are removed.7.3 Clean the filter screen by first disassembling the screen (if practicable).D2532 1737.3.1 Rinse thoroughly with fresh toluene (WarningFlammable).7.3.2 Rinse thoroughly with fresh acetone (WarningFlammable).7.3.3 Dry in oven at approximately 100 C.8. Procedure8.1 For the
48、duration of the test, maintain the bath temperature at the required temperature 60.03 C.8.2 Charge the clean, dry viscometer as prescribed in Test Method D445 and Specifications D446.8.2.1 Affix the drying tubes and carefully flush the moist room air from the viscometer by placing vacuum to the dryi
49、ng tubes.Draw the sample into the working capillary and timing bulb and then place rubber stoppers into the tubes to hold the sample inplace so as to preclude the possibility of any traces of residue moisture condensing on the walls of the capillary and timing bulbwhile the sample cools to test temperature. Moisture must not be allowed to condense on the walls of the working capillary andefflux bulb.8.2.2 Insert the viscometer into the constant-temperature bath, and vertically align the viscometer if a self-aligning holder
