1、Designation: D 4683 04An American National StandardStandard Test Method forMeasuring Viscosity at High Shear Rate and HighTemperature by Tapered Bearing Simulator1This standard is issued under the fixed designation D 4683; the number immediately following the designation indicates the year oforigina
2、l adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defe
3、nse.1. Scope*1.1 This test method covers the laboratory determination ofthe viscosity of engine oils at 150C and 1 3 106s1shear rateusing a tapered bearing simulator-viscometer (TBS Viscom-eter)2equipped with a refined thermoregulator system. OlderTBS units not so equipped must use Test Method D 468
4、387.1.2 The Newtonian calibration oils used to establish this testmethod cover the range from approximately 1.5 to 5.6 cP(mPas) at 150C.1.3 The non-Newtonian reference oil used to establish thistest method has a viscosity of approximately 3.5 cP (mPas) at150C and a shear rate of 1 3 106s1.1.4 Applic
5、ability to petroleum products other than engineoils has not been determined in preparing this test method.1.5 This test method uses the centipoise (cP) as the unit ofviscosity. For information on the equivalent SI unit, themillipascal second (mPas) is shown in parentheses.1.6 This standard does not
6、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.2. Referenced Documents2.1 ASTM Standards:
7、3D 4741 Test Method for Measuring Viscosity at High Tem-perature and High Shear Rate by Tapered-Plug ViscometerD 5481 Test Method for Measuring Apparent Viscosity atHigh-Temperature and High-Shear Rate by Multicell Cap-illary Viscometer3. Terminology3.1 Definitions:3.1.1 densitythe mass per unit vol
8、ume. In the SI, the unitof density is the kilogram per cubic metre, but for practical usea submultiple is more convenient. The gram per cubic centi-metre is 103kg/m3and is customarily used.3.1.2 Newtonian oil or fluidan oil or fluid that at a giventemperature exhibits a constant viscosity at all she
9、ar rates orshear stresses.3.1.3 non-Newtonian oil or fluidan oil or fluid that exhib-its a viscosity that varies with changing shear stress or shearrate.3.1.4 shear ratethe velocity gradient in fluid flow. The SIunit for shear rate is the reciprocal second (s-1).3.1.5 shear stressthe motivating forc
10、e per unit area forfluid flow. The area is the area under shear.3.1.6 viscositythe ratio between the applied shear stressand rate of shear. It is sometimes called the coefficient ofdynamic viscosity. This coefficient is thus a measure of theresistance to flow of the liquid. In the SI the unit of vis
11、cosityis the pascal second; for practical use, a submultiple, millipas-cal second, is more convenient. The centipoise is 1 mPas andis customarily used.3.1.6.1 apparent viscositythe determined viscosity ob-tained by this test method.3.1.6.2 kinematic viscositythe ratio of the viscosity to thedensity
12、of the liquid. It is a measure of the resistance to flow ofa liquid under gravity. In the SI the unit of kinematic viscosityis the metre squared per second; for practical use, a submultiple(millimetre squared per second) is more convenient. Thecentistoke (cSt) is 1 mm2/s and is customarily used.3.2
13、Definitions of Terms Specific to This Standard:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved Feb. 1, 2004. Published March 2004. Originallyapprov
14、ed in 1987. Last previous edition approved in 1996 as D 468396.2The sole source of supply of the apparatus known to the committee at this timeis Tannas Co., 4800 James Savage Rd., Midland, MI 48642. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadqu
15、arters. Your comments will receive careful consideration at a meeting of theresponsible technical committee1, which you may attend.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informa
16、tion, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.1 calibration oils2Newtonian oils used to est
17、ablish thereference framework of viscosity versus torque from which isdetermined the test oil viscosity.3.2.2 contact positionthe rotor height when in rubbingcontact with the stator.3.2.3 idling oil2an oxidatively stable Newtonian oil usedto minimize deposits on the rotor/stator operating surfaceswh
18、en the instrument is held for long periods of time atoperating temperatures of 150C at which other oils may inreasonably short time decompose and leave residues.3.2.4 non-Newtonian reference oil2a specially selectednon-Newtonian reference oil required to establish the propergap between the rotor and
19、 stator to produce an operating shearrate of 1 3 106s1.3.2.5 reciprocal torque intersection, Rtithe rotor positionon the micrometer defined by the intersection of two straightlines. These are generated by the reciprocal indicated torqueversus rotor height for the non-Newtonian NNR-03 and theNewtonia
20、n R-400. The intersection indicates the rotor height atwhich the rotor/stator cell will generate 1 3 106s1shear rate.3.2.6 rotor height (rotor position)the vertical position ofthe rotor relative to the stator and measured by the platformmicrometer.3.2.6.1 DiscussionFor most instruments, a mechanical
21、micrometer is used; the micrometer reading increases as therotor is lowered and approaches the stator. However, if anelectronic micrometer is used, the micrometer reading de-creases when the rotor is lowered.3.2.7 stored positionthe rotor position with the rotor 0.50mm above the contact position.3.2
22、.8 test oilany oil for which apparent viscosity is to bedetermined.4. Summary of Test Method4.1 Amotor drives a tapered rotor that is closely fitted insidea matched stator. The rotor exhibits a reactive torque responsewhen it encounters a viscous resistance from an oil that fills thegap between the
23、rotor and stator. Two oils, a calibration oil anda non-Newtonian reference oil, are used to determine the gapdistance between the rotor and stator so that a shear rate of1 3 106s1is maintained. Additional calibration oils are usedto establish the viscosity/torque relationship which is requiredfor th
24、e determination of the apparent viscosity of test oils at150C.5. Significance and Use5.1 Viscosity at the shear rate and temperature of this testmethod is thought to be representative of the conditionencountered in the bearings of automotive engines in severeservice.5.2 The importance of viscosity a
25、t these conditions toengine lubrication has been addressed in many publications.46. Apparatus6.1 Tapered Bearing Simulator-Viscometer2(Fig. 1)aviscometer consisting of a synchronous two-speed motor thatdrives a slightly tapered bearing in a matched stator (Fig. 2).6.1.1 The motor and rotor are raise
26、d and lowered by meansof a platform, which, in turn, is cantilevered from an elevatordevice. The gap between the rotor and stator is controlled byadjustment of the platform height.6.1.2 The resistive force of the test oil is transferred to theload cell by the turntable on which the motor sits. Thist
27、urntable has a projecting arm on which is mounted a contactball. The rotor is spun by the motor at a constant speed of 50or 60 r/s depending on the frequency of the alternating current.When the rotor encounters viscous resistance, the reactiveforce presses the ball against the platen of the load cel
28、l toregister the resistance given by the viscosity of the oil.NOTE 1An automated system for the TBS Viscometer has beendeveloped employing all the steps in the procedure, and it was used forsome of the round robin data generated for this test method.6.2 ConsoleThe console shown in Fig. 3 contains th
29、epower source for the load cell, thermoregulator circuit, heatingcoil, and motor. It also contains the circuitry for regulating andmonitoring the temperature of the oil in the test cell, as well asthe amplifier and digital readout of the load cell response.NOTE 2The thermoregulator circuit of the TB
30、S Viscometer hasevolved as improvements have been made in the solid-state temperaturecontroller and heater. To achieve the five-minute analysis time specified inthis test method requires a late model solid-state controller with automaticreset coupled to a thermofoil heater with small heat inertia or
31、 afast-responding thermoregulated oil bath.26.3 Air Circulation SystemAflow of dry compressed air ispassed around the stator to provide supplementary coolingwhen testing fluids of higher viscosity (greater than approxi-mately 9 cP). Ports are provided in the stator housing for thecirculation of comp
32、ressed air.6.4 Syringe, glass or polypropylene (in the latter case, use anon-lubricated plunger), equipped with Luer needle lock to fitthe tip of the filling tube for injection of test oil into the annulusbetween the rotor and the stator.4For a comprehensive review, see “The Relationship Between Hig
33、h-TemperatureOil Rheology and Engine Operations,” ASTM Data Series Publication 62. FIG. 1 Tapered Bearing Simulator-ViscometerD46830426.5 FilterA filter is used on the syringe to removeparticles capable of damaging the rotor/stator cell.27. Materials7.1 Calibration Oils2are Newtonian oils of known k
34、ine-matic viscosity and density at 150C. The defined viscosities incentipoise (mPas) are calculated by multiplying the kinematicviscosity in centistokes by the density in grams per cubiccentimetre. Approximate viscosities for the calibration oils arelisted in Table 1. Certified viscosities are suppl
35、ied with eachoil.7.2 Idling OilSee 3.2.3.7.3 Non-Newtonian Reference Oil2is essential in setting therotor/stator gap to 1 3 106s1shear rate. An approximateviscosity of a suitable non-Newtonian reference oil is given inTable 1. The certified viscosity at 1 3 106s1and 150C issupplied with the oil and
36、is matched to the viscosity ofreference fluid R-400 (see Table 1).8. Sampling8.1 A representative sample of test oil is obtained. Whenused oils are evaluated, it is desirable to change the filterattached to the syringe periodically to reduce injection pressurecaused by particle buildup on the filter
37、 surface.NOTE 3Precision for used oils has not been determined.9. Preparation of the Apparatus9.1 Directions for preparation of the tapered bearingsimulator-viscometer and console are supplied with the equip-ment. One of the most important directions to be followed isthe alignment of the rotor/stato
38、r before initial use of theviscometer.9.2 With continuous use, a weekly room-temperature flushof the rotor/stator cell is recommended following directions in11.4.10. Calibration10.1 Proceed to Section 11 if the operating position hasalready been established.10.2 Activating the ConsoleBe sure the MOT
39、OR switchon the console is in the OFF position. Then, turn on thePOWER switch. Leave the console in this standby conditionfor at least 1 h before using the tapered bearing simulator-viscometer.10.3 Oil in Test Cell:10.3.1 If there is no oil in the test cell, slowly inject 50 mLof the idling oil or o
40、ther suitable oxidation-resistant fluid.10.3.2 When there is oil in the test cell, proceed with thedetermination of the stored position as described in 10.4. If thisposition has been determined, proceed to 10.5.10.4 Determining the Stored Position:10.4.1 Bring the operating temperature to 150C by se
41、ttingthe thermostat on the console.10.4.2 Be careful not to touch the hot upper stator surfacewhen the following operation is performed. Slowly lower therotor into the stator by means of the height adjustment wheelon the elevator assembly while turning the flexible shaftconnecting the motor and the
42、rotor with the fingers until slightrubbing contact is felt between the rotor and the stator. Thenslowly continue to lower the rotor in small increments (ap-proximately110 of the smallest division or 0.001 mm untilfurther turning is prevented (without forcing rotation). This isthe point of rubbing co
43、ntact. Record the micrometer reading tothe third decimal place (that is, estimate the last place from theneedle position between the minor division marks). All subse-quent readings of the micrometer dial will be to the nearest0.001 mm.10.4.3 Raise the rotor to a position 0.50 mm (500 microme-tres) a
44、bove the contact position. Record this reading as thestored position.10.4.3.1 It is important to observe whether the micrometerreading is 0.50 mm smaller or 0.50 mm larger than the readingat the contact position. For units that have mechanical mi-crometers, the reading for the stored position will b
45、e 0.50 mmsmaller than that recorded for the contact position. If anelectronic micrometer is used, the reading for the storedposition will be 0.50 mm larger than that recorded for thecontact position. See 3.2.6.1.10.5 Determination of the Reciprocal Torque Intercept (Rti)to Determine Rotor Position f
46、or 1 3 106s1Shear Rate:10.5.1 With the rotor in the stored position, gently move themotor turntable clockwise a few degrees to disengage the ballfrom contact with the platen, hold the motor housing firmly inthis position, set the speed switch to HI and flip the motorswitch to the ON position. Releas
47、e the grip on the motor and letthe reaction torque of the spinning motor bring the ball intocontact with the load cell platen (See Fig. 4).10.5.2 Let the motor run at least 1 h before proceeding to10.5.3.10.5.3 Fill the test cell with NNR-03 non-Newtonian refer-ence oil by either of the methods desc
48、ribed in 10.5.3.1 or10.5.3.2. See Section 8 for sampling precautions. After the testcell has been filled, all subsequent injections should be madewith the motor running. (If this is a first time operation or afterthe viscometer has been idled for more than an hour, make asecond injection after waiti
49、ng the requisite 5 min 30 s.)10.5.3.1 Fill the syringe with 50 6 3 mL of oil. Slowlyinject the oil into the inlet tube of the test cell at a rate ofFIG. 2 Rotor, Stator, and Stator HousingD4683043approximately 2 mL/s. Fluids with viscosities greater than 4 cPat 150C can be preheated to about 40C to make the injectionrate easier to meet.10.5.3.2 A different injection procedure may be used whenthe amount of test fluid is limited. Fill the syringe with 30 mLof fluid and make three 10-mLinjections, waiting 10 s betweeneach injection.10.5
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