1、Designation: D6895 17Standard Test Method forRotational Viscosity of Heavy Duty Diesel Drain Oils at100 C1This standard is issued under the fixed designation D6895; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of the rota-tional viscosity and the shear thinning properties of heavy dutydiese
3、l engine drain oils at 100 C, in the shear rate range ofapproximately 10 s-1to 300 s-1, in the shear stress range ofapproximately 0.1 Pa to 10 Pa and the viscosity range ofapproximately 12 mPas to 35 mPas. Rotational viscosity val-ues can be compared at a shear rate of 100 s-1by this testmethod.2,31
4、.2 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.2. Referenced Do
5、cuments2.1 ASTM Standards:4D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD5967 Test Method for Evaluation of Diesel Engine Oils inT-8 Diesel EngineD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System
6、Performance3. Terminology3.1 Definitions:3.1.1 shear rate, nthe velocity gradient in fluid flow.3.1.1.1 DiscussionFor a Newtonian fluid in a concentriccylinder rotary viscometer in which the shear stress is mea-sured at the inner or outer cylinder surface and ignoring anyend effects, the shear rate
7、is given as follows: 52Ro2Ro22 Ri2(1)54Ro2tRo22 Ri2!where: = shear rate at the surface of the rotor in reciprocalseconds, s1, = angular velocity, rad/s,Ro= outer radius, mm,Ri= inner radius, mm, andt = time for one revolution of the rotor, s.3.1.1.2 DiscussionFor a fluid in a cone and plate viscom-e
8、ter in which the shear stress is measured in a controlled-stressor controlled strain mode of operation, the shear rate is givenas follows: 5B(2)where: = shear rate at the surface of the rotor or stator inreciprocal seconds, s-1, = angular velocity, rad/s,B = cone angle, rad.3.1.2 shear stress, nthe
9、motivating force per unit area forfluid flow.3.1.2.1 DiscussionFor a Newtonian fluid in a concentriccylinder rotary viscometer in which the shear stress is mea-sured at the inner or outer cylinder surface and ignoring anyend effects, the shear stress is given as follows: 5Tr2 Ri2h(3)1This test metho
10、d is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.07 on Flow Properties.Current edition approved Jan. 1, 2017. Published February 2017. Originallyapproved in 2003. Last previous edition approved in
11、 2012 as D6895 06 (2012).DOI: 10.1520/D6895-17.2Selby, K., “Rheology of Sootthickened Diesel Engine Oils,” SAE 981369,May 1998.3George, H. F., Bardasz, E. A., and Soukup, B., “Understanding SMOT throughDesigned Experimentation Part 3: An Improved approach to Drain Oil ViscosityMeasurementsRotational
12、 Rheology,” SAE 97692, May 1997.4For 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.*A Summary of Changes section
13、 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 standardization established in the Decision on Pr
14、inciples for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1where: = shear stress at the surface of the rotor or stator, Pa,Tr= torque applied to the moving fixture, Nm,Ri= inner radius, m, and
15、h = height of the rotor, m3.1.2.2 DiscussionFor a fluid in a cone and plate viscom-eter in which the shear stress is measured in a controlled-stressor controlled-strain mode of operation, the shear stress is givenas follows: 53Tr2R3(4)where: = shear stress at the surface of the rotor or stator, Pa,T
16、r= torque applied to the moving fixture, Nm, andR = radius of the cone.3.2 Definitions of Terms Specific to This Standard:3.2.1 maximum point timeinstrument setting that limitsthe amount of time the instrument will maintain a constantshear stress or shear rate before accepting the value as theequili
17、brium value.3.2.2 rate indexthe exponent, c, in these expressionsrelating shear rate and shear stress: 5 bc(5)ln! 5 lnb!1c ln! (6)where:c = rate index, andb = viscosity coefficient, mPas.3.2.2.1 DiscussionA rate index of c = 1 signifies Newto-nian fluid behavior. Values less than one indicate increa
18、singnon-Newtonian, shear thinning behavior.33.2.3 rotational viscositythe viscosity obtained by use ofthis test method.3.2.4 VIS100 DECrotational viscosity at shear rate of100 s-1, decreasing shear stress or shear rate sweep.3.2.5 VIS100 INCrotational viscosity at shear rate of100 s-1, increasing sh
19、ear stress or shear rate sweep.4. Summary of Test Method4.1 The sample is placed in a controlled stress or controlledshear rate rheometer/viscometer at 100 C. The sample ispresheared at 10 s-1for 30 s followed by heating at 100 C for10 min. An increasing shear rate (approximately 10 s-1to300 s-1) or
20、 shear stress (0.1 Pa to 10 Pa) sweep is run followedby a decreasing sweep. The rotational viscosity for each step(increasing and decreasing) at 100 s-1shear rate is interpolatedfrom the viscosity versus shear rate data table. The rate index,as a measure of shear thinning, is calculated from a plot
21、of ln(shear stress) versus ln (shear rate).5. Significance and Use5.1 Rotational viscosity measurements allow the determina-tion of the non-Newtonian, shear thinning property of drain oil.Rotational viscosity values can be compared at a shear rate of100 s-1by this test method.2,36. Apparatus6.1 This
22、 test method uses rheometers/viscometers of thecontrolled-stress or controlled-rate mode of operation. The testmethod requires the use of concentric cylinder measuringgeometry or cone and plate measuring geometries, with aminimum cone diameter of 50 mm, capable of operating in therange of approximat
23、ely 0.1 Pa to 10 Pa for shear stress and10 s-1to 300 s-1for shear rate.6.2 Instrument data logging or software shall be capable ofdelivering shear stress versus shear rate data and viscosityversus shear rate data in tabular form. During the experiment,a minimum of 20 points must be taken. The method
24、 for datalogging shall be an equilibrium method where the controlledstress or controlled rate value is held constant until the datapoint equilibrium is reached. The use of a maximum point timeis acceptable, but it must be set to at least 30 s.6.3 Temperature shall be controlled to 100 C 6 0.2 C ateq
25、uilibrium. Some rheometers have a 99.9 C set point limitand would be acceptable for this test method.7. Reagents and Materials7.1 Standard Newtonian Reference Oil, calibrated in viscos-ity in the range of 12 mPas to 35 mPas at 100 C.8. Sampling, Test Specimens, and Test Units8.1 Ensure the test spec
26、imen is homogeneous. Engine sam-pling is generally specified in the test method, for example,Test Method D5967. Manual sampling from the container canbe done in accordance with Practice D4057.9. Preparation of Apparatus9.1 Prepare the apparatus in accordance with manufacturersdirections. The apparat
27、us shall be capable of viscosity mea-surement to within 5 % of the standard Newtonian reference oilviscosity and a rate index value of 0.98 to 1.02 indicating aNewtonian fluid.10. Calibration and Standardization10.1 A Newtonian viscosity standard in the range 12 mPasto 35 mPas at 100 C shall be used
28、 to verify instrumentcalibration. Run the procedure as in Section 12.Aplot of shearstress (Pa) versus shear rate (s-1) shall be linearly regressed toyield a slope and intercept. Results shall be:Intercept, 0.9998This calibration procedure should be repeated if anycriteria are not metThe instrument m
29、anufacturer should be contacted if thecriteria cannot be metThe operator shall not proceed with this procedure if thecalibration criteria are not metD6895 172NOTE 1It has been determined that use of a specific reference oil inthe aforementioned viscosity range did not improve the precision. Forlabor
30、atory to laboratory consistency, it is suggested to use Cannon S200 asthe standard calibration fluid.510.2 New SAE 15W-40 oil shall be used as a daily controlchart standard. Run the procedure (see Section 12) and performan analysis (see Section 13). Results shall be a rate indexbetween 0.98 to 1.02
31、and a viscosity value at 100 s-1, mPas,VIS100. Control chart the values of VIS100 and rate index.The procedure shall be checked and the instrument calibrationrechecked if the reference oil does not fall within controllimits. Practice D6299 shall be used as a guide in this area.10.3 Some instruments
32、and geometries will exhibit signifi-cant instrument/electronic noise at low shear stress or lowshear rate levels, or both. This may be determined by plottingviscosity versus shear rate or viscosity versus shear stress formeasurements of the standard oil. A horizontal line is obtainedin regions far f
33、rom noise. Annex A1 shows two examples ofthis type of plot. The minimum shear rate or shear stress to usein the analysis of data can then be determined for the particularinstrument and geometry.11. Conditioning11.1 Shake all new and used oil samples using the followingprocedure. Do not prepare more
34、than two samples at one timefor one instrument.11.2 Ensure cap is tight on container.11.3 Shake vigorously by hand for 30 s. Wait 60 s for airbubbles to dissipate.11.4 A specimen of the sample shall be taken for analysispromptly following the shaking and dissipation procedure of11.3.12. Procedure12.
35、1 Run the procedure in accordance with the instrumentgeometry requirements and the manufacturers recommenda-tions to obtain shear stress versus shear rate data in the rangesof 0.1 Pa to 10 Pa and 10 s-1to 300 s-1. The order of steps is asfollows:12.1.1 Load sample.12.1.2 Equilibrate at 100 C (minimu
36、m 5 min, maximum10 min).12.1.3 Preshear sample at 10 s-1for 30 s.12.1.4 Stop preshear.12.1.5 Preheat sample at 100 C for 10 min.12.1.6 Run increasing stress or rate sweep for duration ofapproximately 10 min to generate data of shear stress, shearrate and viscosity followed immediately by the next st
37、ep. Therun time will vary somewhat among different instruments andprocedures. Times as low as 2 min and as high as 20 min havebeen utilized successfully to run this test method.12.1.7 Run decreasing stress or rate sweep for duration ofapproximately 10 min to generate data of shear stress, shearrate,
38、 and viscosity.12.1.8 Clean sample from instrument in accordance with themanufacturers instructions. Cone and plate systems shall berinsed with a suitable solvent followed by wiping with a rag ortowel.13. Calculation or Interpretation of Results13.1 Analyze the increasing and decreasing sweeps sepa-
39、rately.13.2 Import the shear stress (Pa), shear rate (s-1) andviscosity (mPas) into a spreadsheet program. This calculationmay be done with a calculator. Delete data below the noiselimit as determined in 10.3.13.3 Calculate two additional columns for ln (shear rate)and ln (shear stress). See Appendi
40、x X1 for sample calculation.13.4 Plot the ln stress versus ln rate columns as a scatter plotwith ln rate on the x-axis.13.5 Fit a least squares linear regression to the data plot.Obtain the equation of the line. This line follows Eq 6. Thereis no criterion for correlation coefficient of candidate oi
41、ls. SeeAppendix X1 for sample calculation.13.6 Obtain the slope of the line, c which is the rate index,to three decimal places and the intercept as ln b to four decimalplaces.13.7 Calculate the viscosity at 100 s-1by interpolationbetween two data points spanning 100 s-1as follows:VIS100 5 VIS11D 100
42、 2 T1! (7)where:D = (VIS2 VIS1)/(T2 T1),VIS2 and T2 = viscosity and shear rate respectively at thefirst data point above 100 s-1, andVIS1 and T1 = viscosity and shear rate respectively at thefirst data point below 100 s-1.14. Report14.1 Report the rate index value as c, the viscosity asVIS100 and in
43、tercept as ln b . Label increasing and decreasingsweep data using INC and DEC.14.2 Rate index c = dimensionless, three decimal places,x.xxx.14.3 VIS100 = mPas, two decimal places xx.xx.14.4 ln b = Pa, four decimal places, x.xxxx.15. Precision6,715.1 Precision was found to be dependent on the mean va
44、lueof the measured property. The data in this section was derived5The sole source of supply of the calibration fluid known to the committee at thistime is Cannon Instrument Co., P.O. Box 16, State College, PA 16804. If you areaware of alternative suppliers, please provide this information to ASTM In
45、terna-tional Headquarters. Your comments will receive careful consideration at a meetingof the responsible technical committee,1which you may attend.6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1594. ContactASTM CustomerS
46、ervice at serviceastm.org.7Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1607. ContactASTM CustomerService at serviceastm.org.D6895 173from a six laboratory/six sample interlaboratory study and athree laboratory/seven sampl
47、e interlaboratory study. All datawas pooled to generate the repeatability and reproducibilitydata. VIS100 range was 14.99 to 36.28 mPas and rate indexrange was 0.623 to 1.002.rRRate index, INC 0.140 0.128x 0.592 0.552xRate index, DEC 0.050 0.048x 0.490 0.480xVIS100, INC 0.12 + 0.0089y -2.08 + 0.168y
48、VIS100, DEC 0.33 + 0.0066y -0.54 + 0.073ywhere:x = mean value of rate index, andy = mean value of VIS100 in mPas.15.2 Sample Precision Calculations:15.2.1 The maximum value for rate index is 1.000. Thisoccurs for fluids which exhibit Newtonian behavior as ob-served for fresh diesel oils within the s
49、hear rate range ofmeasurement in this test method. The rate index, DEC repro-ducibility for fresh oils would be:0.490 2 0.480 1.000! 5 0.010and for a drain with a value of 0.900:0.490 2 0.480 0.900! 5 0.05815.2.2 The VIS100 precision values are valid for viscositieswithin the scope of this test method, 12 mPas to 35 mPas. Adrain with a VIS100, DEC value of 15.20 mPas would have arepeatability of:0.3310.0066 15.2! 5 0.430and a reproducibility of:20.5410.073 15.2! 5 0.570
