1、Designation: D7110 05a (Reapproved 2011)Standard Test Method forDetermining the Viscosity-Temperature Relationship of Usedand Soot-Containing Engine Oils at Low Temperatures1This standard is issued under the fixed designation D7110; the number immediately following the designation indicates the year
2、 oforiginal adoption or, in 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.1. Scope1.1 This test method covers how to measure the apparentvisco
3、sity of used and soot-containing engine oils at lowtemperatures.1.2 A shear rate of approximately 0.2 s-1is produced atshear stresses below 200 Pa. Apparent viscosity is measuredcontinuously as the sample is cooled at a rate of 3C per hourover the range of 5 to 40C.1.3 The measurements resulting fro
4、m this test method areviscosity, the maximum rate of viscosity increase (GelationIndex) and the temperature at which the Gelation Index occurs.1.4 Applicability to petroleum products other than engineoils has not been determined in preparing this test method.1.5 The values stated in SI units are to
5、be regarded asstandard. No other units of measurement are included in thisstandard.1.6 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
6、determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D341 Practice for Viscosity-Temperature Charts for LiquidPetroleum ProductsD3829 Test Method for Predicting the Borderline PumpingTemperature of Engine OilD4684 Test Method for Determinatio
7、n of Yield Stress andApparent Viscosity of Engine Oils at Low TemperatureD4057 Practice for Manual Sampling of Petroleum andPetroleum Products3. Terminology3.1 Definitions:3.1.1 apparent viscosity, nthe viscosity obtained by use ofthis test method.3.1.1.1 DiscussionSee 3.1.6 for definition of viscos
8、ity andunits.3.1.2 Newtonian oil, nan oil that, at a given temperature,exhibits a constant viscosity at all shear rates or shear stresses.3.1.3 non-Newtonian oil, nan oil that, at a given tempera-ture, exhibits a viscosity that varies with shear stress or shearrate.3.1.4 shear rate, nvelocity gradie
9、nt perpendicular to thedirection of flow.3.1.4.1 DiscussionThe SI unit for shear rate is the recip-rocal second (1/s; also s-1).3.1.5 shear stress, nforce per unit area in the direction offlow.3.1.5.1 DiscussionThe SI unit for shear stress is thepascal (Pa).3.1.6 viscosity, nthat property of a fluid
10、 which resistsflow.3.1.6.1 DiscussionViscosity is defined as the ratio of theapplied shear stress (force causing flow) and the shear rate(resultant velocity of flow per unit distance from a stationarysurface wet by the fluid). Mathematically expressed:viscosity 5 shear stress/shear rate or, symbolic
11、ally, h5t/G (1)in which the symbols in the second portion of Eq 1 aredefined by 3.1.4 and 3.1.5. The SI unit for viscosity used hereinis millipascal seconds (mPas).3.2 Definitions of Terms Specific to This Standard:3.2.1 air-binding oils, nthose engine oils whose border-line pumping temperatures are
12、 determined by a combination ofgelation and viscous flow.3.2.2 borderline pumping temperature, nthat temperatureat which an engine oil may have such poor flow characteristicsthat the engine oil pump may not be capable of supplyingsufficient lubricant to the engine.1This test method is under the juri
13、sdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved Jan. 1, 2011. Published February 2011. Originallyapproved in 2005. Last previous edition approved in 2005 as D711005a. DOI:10.1520/D71
14、10-05AR11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Driv
15、e, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 calibration oil, nNewtonian oils developed andused to calibrate the viscometer drive module over the viscos-ity range required for this test method.3.2.3.1 DiscussionThese calibration oils are speciallyblended to give sufficient s
16、ensitivity and range for the specialviscometer head used.3.2.4 computer-programmed automated analysis, nuse oftechniques for acquiring analog data, converting these todigital values and using this information to automaticallyrecord and analyze torque output from the viscometer drivemodule and to ren
17、der this information into tabular data andplotted relationships.3.2.4.1 analog-to-digital (A-D) converter, na device forconverting continuously produced electrical signals into dis-crete numerical values capable of being analyzed by computertechnology.3.2.5 critical pumpability temperature, nthe tem
18、peratureat which an oil reaches a viscosity believed to be critical tolimiting pumpability of the oil (see 3.2.6).3.2.6 critical pumpability viscosity, nthat apparent viscos-ity believed to cause pumpability problems in an engine.3.2.7 flow-limited oils, nthose oils whose borderlinepumping temperatu
19、res are determined by viscous flow.3.2.8 gelation, na rheological condition of an oil charac-terized by a marked increase in flow resistance over and abovethe normal exponential increase of viscosity with decreasingtemperature, particularly at lower shear stresses and tempera-tures.3.2.8.1 Discussio
20、nGelation has been attributed to a pro-cess of nucleation and crystallization of oil components and theconsequent formation of a gel-like mass.33.2.9 Gelation Index, nthe maximum value of the incre-mental ratio:log log h1!2log log h2!/log T12 log T2!# (2)in which h is dynamic viscosity and T is temp
21、erature inKelvin over the temperature range scanned when the incremen-tal decrease in temperature is 1K.3.2.9.1 DiscussionThe technique of deriving GelationIndex was first developed and practiced4by collecting infor-mation from a strip-chart recording and applying the empiricalMacCoull-Walther-Wrigh
22、t equation. For further information,see Appendix 1 of Viscosity-Temperature Charts D341.3.2.10 Gelation Index reference oils, nnon-Newtonianoils chosen to give certain levels of Gelation Index as a checkon instrument performance.3.2.11 Gelation Index Temperature, nthe temperature indegrees Celsius a
23、t which the Gelation Index occurs.3.2.12 pre-treatment sample heating bath, na water or airbath to heat the samples for 1.5 h at 90 6 2C before testing.3.2.13 programmable liquid cold bath, na liquid bathhaving a temperature controller capable of being programmedto run the calibration and the analys
24、is portions of the testmethod.3.2.14 temperature controller, na programmable devicewhich, when properly programmed, ramps the temperatureupward or downward at a chosen rate or series of steps whilesimultaneously controlling temperature excursions.3.2.14.1 calibration program, na program to run there
25、quired series of temperatures at which the torque valuesnecessary to calibrate the viscometer drive module are col-lected and analyzed.3.2.14.2 test program, na program to run the test oilanalysis at 1C/h temperature decrease.3.2.14.3 hold program, na program to reach and hold theprogrammable liquid
26、 cold bath at 5C.3.2.15 test cell, nthe combination of the rotor and stator.Critical elements of the test cell are sketched in Fig. 1.3.2.15.1 rotor, na titanium rotor sized to give a compro-mise of sensitivity and range to the determination of viscosityand gelation using this test method.3.2.15.2 s
27、tator, na precision-bore borosilicate glass tube,to which a measured amount of oil is added for the test andwithin which the specially-made rotor turns.3.2.15.2.1 stator collar, na clamp for the stator which alsopositions it on the test cell alignment device.3.2.15.3 test cell alignment device, na s
28、pecial device usedto support the viscometer drive module while maintaining thestator and the rotor coaxial and vertical in regard to theviscometer driveshaft. Later designs admit dry gas into the cellto prevent moisture and frost buildup.3Symposium on Low Temperature Lubricant Rheology Measurement a
29、nd Rel-evance to Engine Operation,ASTM STP1143, Ed. Robert B. Rhodes,ASTM, 1992.4Selby, T. W., “The Use of the Scanning Brookfield Technique to Study theCritical Degree of Gelation of Lubricants at Low Temperatures,” SAE Paper910746, Society of Automotive Engineers, 1991. FIG. 1 Test CellD7110 05a (
30、2011)23.2.16 test oil, nany oil for which apparent viscosity is tobe determined using the procedure described by this testmethod.3.2.17 viscometer drive module, nthe rotor drive andtorque-sensing component of a rotational viscometer.3.2.18 viscometer module support, na part of the test cellalignment
31、 device supporting the viscometer drive module.4. Summary of Test Method4.1 Used and sooted engine oils are analyzed using a specialrotational viscometer with analog or digital output to a com-puter program. A specially made glass stator/metal rotor cell isattached to the viscometer and subjected to
32、 a programmedtemperature change for both calibration and sample analysis.Following calibration of the rotor-stator set, an approximately20-mL test sample of a test lubricating oil is poured into thestator and preheated for 1.5 to 2.0 h at 90C in an oven or waterbath. Shortly after completing the pre
33、heating step, the room-temperature rotor is put into the stator containing the heated oiland coupled to a torque-sensing viscometer head using anadapter to automatically center the rotor in the stator duringtest. A programmable low-temperature bath is used to cool thecell at a specified rate of 3C/h
34、 from 5C to the temperatureat which the maximum torque recordable is exceeded whenusing a speed of 0.3 rpm for the rotor. After the desiredinformation has been collected, the computer program gener-ates the desired viscometric and rheological values from therecorded data.5. Significance and Use5.1 S
35、ignificance of Low Temperature, Low Shear Rate,Engine Oil RheologyThe low-temperature, low-shear visco-metric behavior of an engine oil, whether new, used, or sooted,determines whether the oil will flow to the sump inlet screen,then to the oil pump, then to the sites in the engine requiringlubricati
36、on in sufficient quantity to prevent engine damageimmediately or ultimately after cold temperature starting. Twoforms of flow problems have been identified,3flow-limited andair-binding behavior. The first form of flow restriction, flow-limited behavior, is associated with the oils viscosity; theseco
37、nd, air-binding behavior, is associated with gelation.5.2 Significance of the Test MethodThe temperature-scanning technique employed by this test method was designedto determine the susceptibility of the engine oil to flow-limitedand air-binding response to slow cooling conditions by provid-ing cont
38、inuous information on the rheological condition of theoil over the temperature range of use.3,4,5In this way, bothviscometric and gelation response are obtained in one test.NOTE 1This test method is one of three related to pumpability relatedproblems. Measurement of low-temperature viscosity by the
39、two otherpumpability test methods, D3829 and D4684, hold the sample in aquiescent state and generate the apparent viscosity of the sample at shearrates ranging up to 15 s-1and shear stresses up to 525 Pa at a previouslyselected temperature. Such difference in test parameters (shear rate, shearstress
40、, sample motion, temperature scanning, and so forth) can lead todifferences in the measured apparent viscosity among these methods withsome test oils, particularly when other rheological factors associated withgelation are present. In addition, the three methods differ considerably incooling rates.5
41、.3 Gelation Index and Gelation Index TemperatureThistest method has been further developed to yield parameterscalled the Gelation Index and Gelation Index Temperature. Thefirst parameter is a measure of the maximum rate of torqueincrease caused by the rheological response of the oil as the oilis coo
42、led slowly. The second parameter is the temperature atwhich the Gelation Index occurs.6. Apparatus6.1 Test CellShown in Fig. 1, consisting of a matchedrotor and a stator of the following critical dimensions:6.1.1 Rotor DimensionsCritical length is 65.5 6 0.1 mmand critical diameter is 18.40 6 0.02 m
43、m.6.1.2 Stator DimensionsCritical diameter is 22.05 mm(60.02 mm) at whatever length will satisfy the immersiondepth when the upper oil level is a minimum of 15 mm belowthe cooling liquid level over the entire temperature range.6.2 Viscometer Drive ModulesRotational viscometerdrive modules capable of
44、 producing an analog signal to ananalog-to-digital converter or other analog signal data proces-sor such as a strip-chart recorder.6.2.1 With the rotor and stator described in 6.1.1 and 6.1.2,the viscometer drive module must be capable of measuring toat least 90 000 mPas (cP).6.3 Test Cell Alignment
45、 DeviceSimultaneously maintainsa vertical axial alignment and reasonably consistent positioningof the rotor in the stator to give repeatable torque readout fromtest to test when setting up the apparatus for analysis.6.3.1 Viscometer SupportSupports the viscometer drivemodule and aligns it vertically
46、.6.3.2 Stator CollarClamps the stator and supports it whenthe stator collar is attached to the viscometer support.6.4 Ameans of providing a dry gas atmosphere over the topof the test sample is necessary to prevent condensation andfreezing of water on the oil surface.6.5 Programmable Liquid Cooling B
47、athLiquid bath ca-pable of running either the calibration or the testing programwith temperature control of 60.1C over the temperature rangedesired at 1C/h.6.5.1 Temperature Controller is set up to operate accordingto two programs, the calibration program and the test program.At any temperature the
48、controller modulates temperaturewithin 0.1C of the desired value.6.6 Computer, Analog-to-Digital Converter, and AnalysisProgramMeans of receiving data from the viscometer drivemodule and converting this data into the desired information.6.7 Sample Pre-treatment Water or Air BathA program-mable water
49、 or air bath for both precise control of the test oilsat 90 6 2C and immersion time after the sample reachespre-treatment temperature.6.8 Calibrated Partial-immersion MercuryThermometerAn ASTM 34C thermometer, calibrated at90C and reading to 60.2C.5Shaub, H., “AHistory ofASTMAccomplishments in Low Temperature EngineOil Rheology,” Symposium on Low Temperature Lubricant Rheology Measurementand Relevance to Engine Operation, ASTM STP 1143, Rhodes, R. B., ed., ASTM,1992, pp. 1-19.D7110 05a (2011)37. Materi
