1、Designation: D2532 16Standard 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, in the ca
2、se 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*1.1 Thi
3、s test method covers the determination of the kine-matic viscosity of aircraft turbine lubricants at lowtemperature, and the percent change of viscosity after a 3 h anda 72 h standing period at low temperature.1.1.1 The range of kinematic viscosities covered by this testmethod is from 7700 mm2/s to
4、14 000 mm2/s at 40 C andfrom 7000 mm2/s to 17 500 mm2/s at 51 C. The precisionhas only been determined for those materials, kinematicviscosity ranges, and temperatures as shown in the precisionsection. Kinematic viscosities and percent change of viscositymay be measured and reported at other tempera
5、tures and otherthermal soak period intervals as agreed by the contractingparties.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.2.1 The SI unit used in this test method for KinematicViscosity is mm2/s. For user reference,
6、 1 mm2/s=10-6m2/s =1 cSt.1.3 WarningMercury has been designated by many regu-latory agencies as a hazardous material that can cause centralnervous system, kidney and liver damage. Mercury, or itsvapor, may be hazardous to health and corrosive to materials.Caution should be taken when handling mercur
7、y and mercurycontaining products. See the applicable product MaterialSafety Data Sheet (MSDS) for details and EPAs websitehttp:/www.epa.gov/mercury/faq.htmfor additional informa-tion. Users should be aware that selling mercury and/ormercury containing products into your state or country may beprohib
8、ited by law.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Fo
9、r specific hazardstatements, see Section 7.2. Referenced Documents2.1 ASTM Standards:2D445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)D446 Specifications and Operating Instructions for GlassCapillary Kinematic ViscometersD6300 Practice
10、 for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricantsE1 Specification for ASTM Liquid-in-Glass ThermometersE563 Practice for Preparation and Use of an Ice-Point Bathas a Reference TemperatureE644 Test Methods for Testing Industrial Resistance Ther-
11、mometersE1137 Specification for Industrial Platinum Resistance Ther-mometersE1750 Guide for Use of Water Triple Point CellsE2593 Guide for Accuracy Verification of Industrial Plati-num Resistance ThermometersE2877 Guide for Digital Contact Thermometers2.2 Other Documents:MIL-PRF-7808 Lubricating Oil
12、, Aircraft Turbine Engine,Synthetic Base3MIL-PRF-23699 Lubricating Oil, Aircraft Turbine Engine,Synthetic Base, NATO Code Number O-15633. Terminology3.1 Definitions:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct
13、responsibility ofSubcommittee D02.07 on Flow Properties.Current edition approved Dec. 1, 2016. Published January 2017. Originallyapproved in 1966. Last previous edition approved in 2014 as D2532 14. DOI:10.1520/D2532-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact
14、ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.
15、daps.dla.mil.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standar
16、dization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.1 digital contact thermometer (DCT), nan electronicdevice consisting of a digital displ
17、ay and associated tempera-ture sensing probe.4. Summary of Test Method4.1 Kinematic viscosity and percent change is determined atlow temperature using apparatus defined in Test Method D445and Specifications D446 at time intervals of 3 h and 72 hfollowing an initial measurement at 35 min.5. Significa
18、nce and Use5.1 Aircraft turbine lubricants, upon standing at low tem-peratures for prolonged periods of time, may show an increasein kinematic viscosity. This increase may cause lubricationproblems in aircraft engines. Thus, this test method is used toensure that the kinematic viscosity does not exc
19、eed themaximum kinematic viscosity in certain specifications foraircraft turbine lubricants.6. Apparatus6.1 Viscometers, drying tubes, low-temperature bath,thermometer, timer, secondary viscosity standard, filter, andcleaning supplies are described in detail in Test Method D445.6.2 ViscometerThe vis
20、cometer shall meet the require-ments of Test Method D445 and Specifications D446 and be ofthe type in which the sample can be rerun without cleaning theviscometer. Suitable holders should be used. For convenienceit is recommended that the viscometer size be chosen to keepthe efflux time between 200
21、s and 1000 s.NOTE 1Consult Specifications D446 regarding calibration constantcorrection for the actual test temperature when using Specifications D446viscometers that are not suspended level types.6.3 Drying TubesFit the viscometer openings with dryingtubes filled with indicating silica gel, using c
22、otton at top andbottom to hold the loosely packed desiccant in place. Providea cross-connection on the viscometer side of the drying tubes(which can be closed by a pinch clamp or stopcock while liquidis being drawn into the efflux bulb) so that the restriction to airflow will not cause error. Replac
23、e the silica gel when alavender color is noticeable.6.4 Viscosity Temperature BathThe constant-temperaturebath must be capable of holding several viscometers at once. Itmust have adequate stirring of the liquid medium (Note 2) andbalance between heat losses such that the bath temperature canbe maint
24、ained at the required temperature 60.03 C.NOTE 2Isopropanol or other clear, low-freezing point liquid may beused as a bath liquid.6.5 Temperature Measuring DeviceUse either a digitalcontact thermometer as described in 6.5.2 with equal or betteraccuracy or a calibrated ASTM Kinematic Viscosity TestTh
25、ermometer such as 73C (40 C) or 74C or 43C (51 C)conforming to the requirements as prescribed in SpecificationE1 which have an accuracy after correction of 60.03 C orbetter. The ASTM 74C thermometer has a specification be-tween 55.4 C and 52.6 C but is available from somesuppliers with the scale exp
26、anded to cover 51 C. The 43Cthermometer is only graduated in 0.1 C increments so inter-pretation at midpoints between the lines may be required.6.5.1 When using liquid-in-glass thermometers, use a mag-nifying device to read the thermometer to the nearest15division (for example, 0.02 C on thermometer
27、s graduated in0.1 C increments) to ensure that the required test temperatureand temperature control capabilities are met.6.5.1.1 Check the thermometers ice point at least annuallyusing an ice bath or a constant temperature bath against areference thermometer. If the corrected temperature readingerro
28、r is greater than the temperature tolerance, then thethermometer must be recalibrated.6.5.2 When using a digital contact thermometer (DCT), thefollowing requirements shall apply:Criteria Minimum RequirementsDCT E2877 Class ADisplay resolution 0.01 C, recommended 0.001 CDisplay accuracy 30 mK (0.03 C
29、) for combined probe andsensorSensor type RTD, such as a PRT or thermistorDrift less than 10 mK (0.01 C) per yearResponse time less than or equal to6sasdefined in Speci-fication E1137Linearity 10 mK over range of intended useCalibration Report The DCT shall have a report of temperaturecalibration tr
30、aceable to a national calibrationor metrology standards body issued by acompetent calibration 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 Th
31、e calibration report shall include at least 3calibration temperatures at least 5 C apartwhich are appropriate for its intended use.6.5.2.1 For a constant temperature bath employed, the DCTprobe shall be immersed by more than its minimum immersiondepth in a constant temperature bath so that the cente
32、r of theprobes sensing region is at the same level as the lower half ofthe working capillary provided the probes minimum immer-sion depth is met and is no less than indicated on the calibrationcertificate. The end of the probe sheath shall not extend past thebottom of the viscometer. It is preferabl
33、e for the center of thesensing element to be located at the same level as the lowerhalf of the working capillary as long as the minimum immer-sion requirements are met.NOTE 3With respect to DCT probe immersion depth, a procedure isavailable in Test Methods E644, Section 7 (Minimum Immersion LengthTe
34、st), for determining the minimum depth. With respect to an ice bath,Practice E563 provides guidance on the preparation of an ice bath,however variance from the specific steps is permitted provided preparationis consistent as it is being used to track change in calibration.6.5.2.2 Verify the DCT cali
35、bration at least annually. Theprobe shall be recalibrated when the check value differs bymore than 0.01 C from the last probe calibration. Verificationcan be accomplished with the use of a water triple point cell, anice bath, or other suitable constant temperature device whichhas a known temperature
36、 value of suitable precision. SeePractice E563, Guide E1750, and Guide E2593 for moreinformation regarding checking calibrations.6.5.2.3 In the case of constant temperature baths used ininstruments for automatic viscosity determinations, the user isto contact the instrument manufacturer for the corr
37、ect DCT thathas performance equivalence to that described here.D2532 1626.6 Timing DeviceUse any timing device, spring-woundor digital, that is capable of taking readings with a discrimi-nation of 0.1 s or better and has an accuracy within 60.07 %(see Annex A3 of Test Method D445) of the reading whe
38、ntested over the minimum and maximum intervals of expectedflow times.6.6.1 Timing devices powered by alternating electric currentmay be used if the current frequency is controlled to anaccuracy of 0.05 % or better. Alternating currents, as providedby some public power systems, are intermittently rat
39、her thancontinuously controlled. When used to actuate electrical timingdevices, such control can cause large errors in kinematicviscosity flow time measurements.6.7 Secondary Viscosity Standards.7. Procedure for Cleaning Viscometers and Filter Screen7.1 Apply air pressure or suction to the viscomete
40、r toremove any previous test specimen. Allow the viscometer todrain for 5 min.7.1.1 Wash the viscometer four times, inside and out, withfresh toluene (WarningFlammable) using suction as re-quired. Allow the viscometer to drain.7.1.2 Wash the viscometer four times, inside and out, withacetone, and al
41、low to drain for 5 min. Then dry with vacuumsuction.7.2 If organic or other deposits are visible in the viscometer,clean the viscometer thoroughly by filling it completely withglass cleaning solution for several hours to remove residualtraces of organic deposits. Allow to drain for 5 min. It isessen
42、tial that strong alkaline cleaning solutions are not used aschanges in the viscometer calibration can occur.7.2.1 Rinse viscometer inside and out with distilled wateruntil all traces of the cleaning solution are completely re-moved. Allow to drain for 5 min.7.2.2 Dry with filtered dry air, a vacuum
43、line, or in an ovenat approximately 100 C for approximately 30 min until alltraces of water are removed.7.3 Clean the filter screen by first disassembling the screen(if practicable).7.3.1 Rinse thoroughly with fresh toluene (WarningFlammable).7.3.2 Rinse thoroughly with fresh acetone (WarningFlammab
44、le).7.3.3 Dry in oven at approximately 100 C.8. Procedure8.1 For the duration of the test, maintain the bath tempera-ture at the required temperature 60.03 C.8.2 Charge the clean, dry viscometer as prescribed in TestMethod D445 and Specifications D446.8.2.1 Affix the drying tubes and carefully flush
45、 the moistroom air from the viscometer by placing vacuum to the dryingtubes. Draw the sample into the working capillary and timingbulb and then place rubber stoppers into the tubes to hold thesample in place so as to preclude the possibility of any tracesof residue moisture condensing on the walls o
46、f the capillaryand timing bulb while the sample cools to test temperature.Moisture must not be allowed to condense on the walls of theworking capillary and efflux bulb.8.2.2 Insert the viscometer into the constant-temperaturebath, and vertically align the viscometer if a self-aligningholder has not
47、been used. After insertion, allow 20 min to 30min for the viscometer to reach bath temperature, and removethe stoppers. Where one bath is used to accommodate severalviscometers, never add or withdraw, or clean a viscometerwhile any other viscometer is in use for measuring an efflux(flow) time.8.2.3
48、Start the first determination of kinematic viscosity 35min 6 1 min after the viscometer is placed in the bath. Usesuction (if the sample contains no volatile constituents) orpressure to adjust the head level of the test sample to a positionin the capillary arm of the instrument about 7 mm above thef
49、irst timing mark, unless any other value is stated in theoperating instructions for the viscometer. Measure a singleefflux time, in seconds to within 0.1 s or better, the timerequired for the advancing ring of contact (meniscus) to passfrom the first timing mark to the second. If this flow time is lessthan the specified minimum (see Specifications D446), select aviscometer with a capillary of smaller diameter and repeat theoperation. Calculate the kinematic viscosity as per subsection9.1 and record the measurement. Be careful that
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