ASTM D1092-12(2017) Standard Test Method for Measuring Apparent Viscosity of Lubricating Greases.pdf

1、Designation: D1092 12 (Reapproved 2017)Standard Test Method forMeasuring Apparent Viscosity of Lubricating Greases1This standard is issued under the fixed designation D1092; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year

2、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. Scope1.1 This test method covers measu

3、rement, in poises, of theapparent viscosity of lubricating greases in the temperaturerange from 54 C to 38 C (65 F to 100 F). Measurementsare limited to the range from 25 P to 100 000 P at 0.1 s1and1 P to 100 P at 15 000 s1.NOTE 1At very low temperatures the shear rate range may be reducedbecause of

4、 the great force required to force grease through the smallercapillaries. Precision has not been established below 10 s1.1.2 This standard uses inch-pound units as well as SI(acceptable metric) units. The values stated first are to beregarded as standard. The values given in parentheses are forinfor

5、mation only. The capillary dimensions in SI units in Fig.A1.1 and Fig. A1.2 are standard.1.3 WARNINGMercury has been designated by manyregulatory agencies as a hazardous material that can causecentral nervous system, kidney and liver damage. Mercury, orits vapor, may be hazardous to health and corro

6、sive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product Ma-terial Safety Data Sheet (MSDS) for details and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfor addi-tional information. Users should be aware that selling mercuryand/or merc

7、ury containing products into your state or countrymay be prohibited by law.1.3.1 In addition, temperature measuring devices such asliquid-in-glass thermometers, thermocouples, thermistors, orplatinum resistance thermometers that provide equivalent orbetter accuracy and precision, that cover the temp

8、erature rangefor ASTM thermometer 49C, may be used.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, health and environmental practices and deter-mine the ap

9、plicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued b

10、y the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D88 Test Method for Saybolt ViscosityD217 Test Methods for Cone Penetration of LubricatingGreaseD3244 Practice for Utilization of Test Data to DetermineConformance with Specifications

11、3. Terminology3.1 Definitions:3.1.1 apparent viscosity, nof a lubricating grease is theratio of shear stress to shear rate calculated from Poiseuillesequation, and is measured in poises (see 10.1).3.1.2 capillary, nFor the purpose of this test method, acapillary is any right cylindrical tube having

12、a length todiameter ratio of 40 to 1.3.1.3 shear rate, nthe rate at which a series of adjacentlayers of grease move with respect to each other; proportionalto the linear velocity of flow divided by the capillary radius,and is thus expressed as reciprocal seconds.4. Summary of Test Method4.1 The samp

13、le is forced through a capillary by means of afloating piston actuated by the hydraulic system. From thepredetermined flow rate and the force developed in the system,the apparent viscosity is calculated by means of Poiseuillesequation.Aseries of eight capillaries and two pump speeds areused to deter

14、mine the apparent viscosity at sixteen shear rates.The results are expressed as a log-log plot of apparent viscosityversus shear rate.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D

15、02.G0.02 on Consistency and Related Rheological Tests.Current edition approved Aug. 1, 2017. Published August 2017. Originallyapproved in 1950. Last previous edition approved in 2012 as D1092 12. DOI:10.1520/D1092-12R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact

16、ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard

17、was developed in accordance with internationally recognized principles on standardization 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.15. Signifi

18、cance and Use5.1 Apparent viscosity versus shear rate information can beuseful in predicting pressure drops in grease distributionsystems under steady-state flow conditions at constant tem-perature.6. Apparatus6.1 The assembled pressure viscometer consists of fourmajor divisions, the power system, t

19、he hydraulic system, thegrease system (described in the annex and shown in Fig. 1),and a bath of optional design. Fig. 2 is a photograph of the firstthree divisions as commonly used at room temperature. Thisform of the apparatus can be used with a cylindrical insulatedtank 178 mm (7 in.) in diameter

20、 and 508 mm (20 in.) deep. Thebath medium may be kerosene or alcohol cooled manually withdry ice. Alternatively the grease system, the grease andhydraulic system, or all three major divisions can be built intoany liquid or air bath that will cover the temperature range andmaintain the grease at test

21、 temperature 60.25 C (60.5 F).7. Sampling7.1 A single filling of the grease cylinder requires about0.223 kg (12 lb) of grease which is the minimum size sample.NOTE 2It is possible for an experienced operator to complete the 16single determinations with a single filling. However, some samples reachth

22、e equilibrium pressure slowly, making it advisable to have a sample ofseveral pounds available.7.2 Generally no special preparation of the sample is nec-essary.NOTE 3The apparatus works the samples to some extent as they passthrough the capillary. Somewhat better precision is obtained if they arepre

23、viously worked as described in Test Methods D217. Working of somegreases may cause aeration.NOTE 4It is desirable to filter some greases through a 60-mesh screento prevent plugging the No. 8 capillary. Follow prudent laboratory practiceto keep equipment cleaned and flushed before use.8. Calibration

24、and Standardization8.1 To calibrate the hydraulic system, remove the greasecylinder and replace it with a needle valve. Select a hydraulicFIG. 1 Schematic Drawing of ApparatusFIG. 2 Photograph of ApparatusD1092 12 (2017)2oil of about 2000 cSt (2000 mm2/s) viscosity at the testtemperature. Fill the s

25、ystem with hydraulic oil and circulate theoil until it is free of air bubbles. At atmospheric pressure,quickly place a 60 mL Saybolt receiving flask (Test MethodD88), under the outlet and start a timer. Determine the deliverytime for 60 mL and calculate the flow rate in cubic centimetresper second a

26、ssuming 1 mL equal to 1 cm3. Repeat this obser-vation at 500 psi, 1000 psi, 1500 psi (3.45 MPa, 6.89 MPa,10.4 MPa) and at sufficient pressures above 1500 psi to de-velop a calibration curve of the type as shown in Fig. 3. Thedeveloped curve of the type is used to correct flow rates whengrease is dis

27、pensed. Repeat the calibration at intervals todetermine if wear is changing the pump flow.8.2 An alternative procedure for the calibration of thehydraulic system is the measurement of the rate of flow of thetest grease. To cover the desired range of shear rates, flow ratesover an approximate range o

28、f pressure are determined. Anysuitable means of measuring the rate of grease flow may beused.9. Procedure9.1 Charge the sample so as to reduce inclusion of air to aminimum. Soft greases may be poured into the cylinder ordrawn up by vacuum; heavy samples must be hand packed.When filling the cylinder

29、by vacuum, remove the capillary endcap and place the piston flush with the open end and then insertinto the sample. Apply vacuum to the opposite end of thecylinder until the cylinder is fully charged with grease. Thismust be facilitated by tapping with a wooden block. Replacethe capillary end cap an

30、d fill the upper end of the cylinderabove the piston with hydraulic oil.9.2 Fill the entire hydraulic system with hydraulic oil.Disconnect, invert and fill the gage and gage connections withoil. With the entire hydraulic system connected and completelyfilled with oil, adjust the temperature of the s

31、ample to the testtemperature 60.25 C (60.5 F) as determined by a thermo-couple inserted in the capillary end cap. Operate the pump untiloil flows from the gage connection on the viscometer beforereconnecting the gage. With the entire viscometer assembled,circulate hydraulic oil with the return valve

32、 open until all traceof air is eliminated.9.2.1 The time to attain test temperature varies with thebath. At 54 C (65 F) the grease in an unstirred liquid bathshould be ready to test in 2 h.Air baths can take as long as 8 h.AnASTM Thermometer 74F in the bath serves as a convenientsecondary means of m

33、easuring the temperature at 54 C(65 F). In an air bath the thermometer must be within25.4 mm of the capillary.NOTE 5The use of an equivalent non-mercury filled replacementthermometer, such as a thermistors, platinum resistance thermometer,other liquid in glass thermometer, or thermocouple is under s

34、tudy inSubcommittee E20.09.9.3 With No. 1 capillary in place and the 40-tooth gearconnected, operate the pump with the return valve closed untilequilibrium pressure is obtained. Record the pressure. Changeto the 64-tooth gear and again establish equilibrium. Recordand relieve the pressure. Replace t

35、he No. 1 capillary withsubsequent ones and repeat these operations until tests havebeen run with all capillaries at both flow rates. With some softor hard greases, it cannot be practical to use all of thecapillaries.NOTE 6It may be necessary to refill the cylinder with fresh greasewhen all 16 determ

36、inations are to be made.NOTE 7The use of an equivalent non-mercury filled replacementthermometer is under study in Subcommittee E20.09.10. Calculation10.1 Calculate apparent viscosity of the grease as follows:apparent viscosity! 5 F/S (1)where F is the shear stress, and S is the shear rate. Therefor

37、e: 5 F/S 5pR2/2RL4v/t!/R35 pR4/8Lv/t! 5 P68944R4/8Lv/t! (2)where:p = pressure dynes/cm2,L = capillary length, cm,P = observed gage pressure, psi (multiply by 68944 toconvert to dynes per square centimetre),R = radius of capillary used, cm, andv/t = flow rate, cm3/s.10.2 Calculations may be reduced t

38、o a minimum by prepar-ing a table of 16 constants, one for each capillary and shear rate(Table 1). For example, viscosity with No. 1 capillary and the40-tooth gear is given as follows: 5 Pobserved!68944R4/8Lv/t! or PK1240!where:K1240!5 68944 R4/8Lv/t! (4)10.3 Also calculate the shear rates as follow

39、s:S 5 4v/t!/R3(5)Correct the flow rate to correspond to the observed pressureby reference to Fig. 3. Calculate 16 shear rates for the eightcapillaries and two flow rates. This calculation need not berepeated for each run since it will remain constant until reca-libration of the pump indicates a revi

40、sion.10.4 Plot a curve of apparent viscosity versus shear rate onlog-log paper, as shown in Fig. 4.FIG. 3 Typical Pump Calibration CurveD1092 12 (2017)3NOTE 8Shear stresses also can be calculated by multiplying apparentviscosities by their corresponding shear rates. For solving various prob-lems inv

41、olving the steady flow of greases, shear stress-shear rate relation-ships may be plotted on appropriate charts. Instructions on the use of thesecharts are given in the article by Rein and McGahey.311. Precision and Bias11.1 Due to the nature of the results, the precision of thistest method was not o

42、btained according to RR:D02-1007,“Manual on Determining Precision Data for ASTM Methodson Petroleum Products and Lubricants.” The precision of thistest method as determined by statistical examination of inter-laboratory results is as follows:3Rein and McGahey, “Predicting Grease Flow in Large Pipes,

43、” NLGISpokesman, April 1965.TABLE 1 Suggested Data Sheet for Recording Test Results (With Illustrative Test Values)Sample . .No. 2 Grease Temperature .25CDate. .Nov. 1, 1948 Operator. .R.S.123 4A5B6A7CCapillary GearObservedPressure,P, psiK = 68944R4/(8Lv/t)ApparentViscosity,n poises,= PKShear Rate,S

44、 ,s1=(4v/t)/R3Shear Stress,dynes per sqcm = n S1 40 25.5 28.10 716 15 10 7402 40 38.3 6.83 267 61 16 3003 40 48.8 3.61 176 120 21 1004 40 63.5 1.90 120 230 27 8005 40 96.5 0.89 86 480 41 3006 40 125 0.58 72.6 755 54 8007 40 286 0.139 39.8 3 140 125 0008 40 546 0.0464 25.3 9 320 235 5001 64 29.5 17.6

45、0 520 24 12 4702 64 45.8 4.27 195 98 19 1003 64 60 2.26 135.5 195 26 4004 64 82.3 1.19 97.9 370 36 2505 64 130 0.556 72.4 770 55 8006 64 165 0.363 59.9 1 220 73 2007 64 384 0.087 33.4 5 020 167 5008 64 720 0.029 20.9 14 900 311 000AValues in this column are predetermined.BColumn 3 times Column 4.CCo

46、lumn 5 times Column 6.FIG. 4 Typical Chart for Apparent Viscosity versus Shear RateD1092 12 (2017)411.2 The data in 11.2.1 and 11.2.2 should be used forjudging the acceptability of results (95 % confidence) accord-ing to the concept of precision as given in Practice D3244.11.2.1 RepeatabilityThe dif

47、ference between two testresults, obtained by the same operator with the same apparatusunder constant operating conditions on identical test material,would in the long run, in the normal and correct operation ofthe test method, exceed the values given in Table 2 only in onecase in twenty.11.2.2 Repro

48、ducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of the testmethod, exceed the values given in Table 2 only in one case intwenty.

49、11.2.3 Reproducibility of the curve drawing operation var-ies from 5 to 8 % for the above samples. These data are basedupon curve values of apparent viscosity at the six shear rates.A separate curve was drawn for each run.11.3 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in TestMet