1、Designation: D6895 06 (Reapproved 2012)D6895 17Standard Test Method forRotational Viscosity of Heavy Duty Diesel Drain Oils at100C100 C1This standard is issued under the fixed designation D6895; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f 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. Scope Scope*1.1 This test method covers the determination of the rotational viscosity and the shear thi
3、nning properties of heavy duty dieselengine drain oils at 100C,100 C, in the shear rate range of approximately 1010 s-1 to 300 s300 s-1, in the shear stress range ofapproximately 0.10.1 Pa to 10 Pa 10 Pa and the viscosity range of approximately 1212 mPas to 35 mPas. 35 mPas. Rotationalviscosity valu
4、es can be compared at a shear rate of 100 s-1 by this test method.2,31.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the
5、applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:4D4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD5967 Test Method for Evaluation of Diesel Engine Oils in T-8 Diesel EngineD6299 Practice for Applying Statistical Quality Assurance an
6、d Control Charting Techniques to Evaluate Analytical Measure-ment System 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 concentric cylinder rotary viscometer in which the shear stress is measured at the inn
7、er or outer cylindersurface and ignoring any end effects, the shear rate is given as follows: 5 2Ro2Ro22R i2 (1)5 4Ro2tRo22Ri2!where: = shear rate at the surface of the rotor in reciprocal seconds, s1, = angular velocity, rad/s,1 This test method is under the jurisdiction ofASTM Committee D02 on Pet
8、roleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved Nov. 1, 2012Jan. 1, 2017. Published November 2012February 2017. Originally approved in 2003. Last previous edition approved in 20062012as D6895D6895 06 (20
9、12).06. DOI: 10.1520/D6895-06R12.10.1520/D6895-17.2 Selby, K., “Rheology of Sootthickened Diesel Engine Oils,” SAE 981369, May 1998.3 George, H. F., Bardasz, E. A., and Soukup, B., “Understanding SMOT through Designed Experimentation Part 3: An Improved approach to Drain Oil ViscosityMeasurementsRot
10、ational Rheology,” SAE 97692, May 1997.George, H. F., Bardasz, E.A., and Soukup, B., “Understanding SMOT through Designed Experimentation Part3: An Improved approach to Drain Oil Viscosity MeasurementsRotational Rheology,” SAE 97692, May 1997.4 For referencedASTM standards, visit theASTM website, ww
11、w.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of wh
12、at changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered th
13、e official document.*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 States1Ro = outer radius, mm,Ri = inner radius, mm, andt = time for one revolution of the rotor, s.3.1.1.2 D
14、iscussionFor a fluid in a cone and plate viscometer in which the shear stress is measured in a controlled-stress or controlled strain modeof operation, the shear rate is given as follows: 5B (2)where: = shear rate at the surface of the rotor or stator in reciprocal seconds, s-1, = angular velocity,
15、rad/s,B = cone angle, rad.3.1.2 shear stress, nthe motivating force per unit area for fluid flow.3.1.2.1 DiscussionFor a Newtonian fluid in a concentric cylinder rotary viscometer in which the shear stress is measured at the inner or outer cylindersurface and ignoring any end effects, the shear stre
16、ss is given as follows: 5 Tr2 Ri2 h (3)D6895 172where: = shear stress at the surface of the rotor or stator, Pa,Tr = torque applied to the moving fixture, Nm,Ri = inner radius, m, andh = height of the rotor, m3.1.2.2 DiscussionFor a fluid in a cone and plate viscometer in which the shear stress is m
17、easured in a controlled-stress or controlled-strain modeof operation, the shear stress is given as follows: 5 3Tr2R3 (4)where: = shear stress at the surface of the rotor or stator, Pa,Tr = torque applied to the moving fixture, Nm, andR = radius of the cone.3.2 Definitions of Terms Specific to This S
18、tandard:3.2.1 maximum point timeinstrument setting that limits the amount of time the instrument will maintain a constant shear stressor shear rate before accepting the value as the equilibrium value.3.2.2 rate indexthe exponent, c, in these expressions relating shear rate and shear stress:shear str
19、ess5bshear rate!c (5) 5bc (5)lnshear stress!5lnb1clnshear rate! (6)ln!5lnb!1c ln! (6)where:c = rate index, andb = viscosity coefficient, mPas.3.2.2.1 DiscussionA rate index of c = 1 signifies Newtonian fluid behavior. Values less than one indicate increasing non-Newtonian, shear thinningbehavior.33.
20、2.3 rotational viscositythe viscosity obtained by use of this test method.3.2.4 VIS100 DECrotational viscosity at shear rate of 100 s100 s-1, decreasing shear stress or shear rate sweep.3.2.5 VIS100 INCrotational viscosity at shear rate of 100 s100 s-1, increasing shear stress or shear rate sweep.4.
21、 Summary of Test Method4.1 The sample is placed in a controlled stress or controlled shear rate rheometer/viscometer at 100C.100 C. The sample ispresheared at 10 s-1 for 30 s 30 s followed by heating at 100C100 C for 10 min. 10 min.An increasing shear rate (approximately1010 s-1 to 300 s300 s-1) or
22、shear stress (0.1(0.1 Pa to 10 Pa) 10 Pa) sweep is run followed by a decreasing sweep. The rotationalviscosity for each step (increasing and decreasing) at 100 s100 s-1 shear rate is interpolated from the viscosity versus shear ratedata table. The rate index, as a measure of shear thinning, is calcu
23、lated from a plot of ln (shear stress) versus ln (shear rate).5. Significance and Use5.1 Rotational viscosity measurements allow the determination of the non-Newtonian, shear thinning property of drain oil.Rotational viscosity values can be compared at a shear rate of 100 s100 s-1 by this test metho
24、d.2,36. Apparatus6.1 This test method uses rheometers/viscometers of the controlled stress or controlled rate controlled-stress or controlled-ratemode of operation. The test method requires the use of concentric cylinder measuring geometry or cone and plate measuringgeometries, with a minimum cone d
25、iameter of 50 mm, capable of operating in the range of approximately 0.10.1 Pa to 10 Pa 10 Pafor shear stress and 1010 s-1 to 300 s300 s-1 for shear rate.D6895 1736.2 Instrument data logging or software shall be capable of delivering shear stress versus shear rate data and viscosity versusshear rate
26、 data in tabular form. During the experiment, a minimum of 20 points must be taken. The method for data logging shallbe an equilibrium method where the controlled stress or controlled rate value is held constant until the data point equilibrium isreached. The use of a maximum point time is acceptabl
27、e, but it must be set to at least 30 s.30 s.6.3 Temperature shall be controlled to 100100 C 6 0.2C0.2 C at equilibrium. Some rheometers have a 99.9C99.9 C setpoint limit and would be acceptable for this test method.7. Reagents and Materials7.1 Standard Newtonian Reference Oil, calibrated in viscosit
28、y in the range of 1212 mPas to 35 mPas 35 mPas at100C.100 C.8. Sampling, Test Specimens, and Test Units8.1 Ensure the test specimen is homogeneous. Engine sampling is generally specified in the test method, for example, TestMethod D5967. Manual sampling from the container can be done in accordance w
29、ith Practice D4057.9. Preparation of Apparatus9.1 Prepare the apparatus in accordance with manufacturers directions. The apparatus shall be capable of viscosity measurementto within 5 % of the standard Newtonian reference oil viscosity and a rate index value of 0.98 to 1.02 indicating a Newtonian fl
30、uid.10. Calibration and Standardization10.1 A Newtonian viscosity standard in the range 1212 mPas to 35 mPas 35 mPas at 100C100 C shall be used to verifyinstrument calibration. Run the procedure as in Section 12. A plot of shear stress (Pa) versus shear rate (s-1) shall be linearlyregressed to yield
31、 a slope and intercept. Results shall be:Intercept, 0.9998This calibration procedure should be repeated if anycriteria are not metThe instrument manufacturer should be contacted if thecriteria cannot be metThe operator shall not proceed with this procedure if thecalibration criteria are not metD6895
32、 174NOTE 1It has been determined that use of a specific reference oil in the aforementioned viscosity range did not improve the precision. For laboratoryto laboratory consistency, it is suggested to use Cannon S200 as the standard calibration fluid.510.2 New SAE 15W-40 oil shall be used as a daily c
33、ontrol chart standard. Run the procedure (see Section 12) and perform ananalysis (see Section 13). Results shall be a rate index between 0.98 to 1.02 and a viscosity value at 100 s100 s-1, mPas, VIS100.Control chart the values of VIS100 and rate index. The procedure shall be checked and the instrume
34、nt calibration rechecked if thereference oil does not fall within control limits. Practice D6299 shall be used as a guide in this area.10.3 Some instruments and geometries will exhibit significant instrument/electronic noise at low shear stress or low shear ratelevels, or both. This may be determine
35、d by plotting viscosity versus shear rate or viscosity versus shear stress for measurementsof the standard oil.Ahorizontal line is obtained in regions far from noise. AnnexA1 shows two examples of this type of plot. Theminimum shear rate or shear stress to use in the analysis of data can then be det
36、ermined for the particular instrument and geometry.11. Conditioning11.1 Shake all new and used oil samples using the following procedure. Do not prepare more than two samples at one time forone instrument.11.2 Ensure cap is tight on container.11.3 Shake vigorously by hand for 30 s. Wait 60 s 30 s. W
37、ait 60 s for air bubbles to dissipate.11.4 A specimen of the sample shall be taken for analysis promptly following the shaking and dissipation procedure of 11.3.12. Procedure12.1 Run the procedure in accordance with the instrument geometry requirements and the manufacturers recommendations toobtain
38、shear stress versus shear rate data in the ranges of 0.10.1 Pa to 10 Pa 10 Pa and 1010 s-1 to 300 s300 s-1. The order of stepsis as follows:12.1.1 Load sample.12.1.2 Equilibrate at 100C100 C (minimum 5 min, maximum 10 min).5 min, maximum 10 min).12.1.3 Preshear sample at 10 s10 s-1 for 30 s. 30 s.12
39、.1.4 Stop preshear.12.1.5 Preheat sample at 100C100 C for 10 min.10 min.12.1.6 Run increasing stress or rate sweep for duration of approximately 10 min 10 min to generate data of shear stress, shearrate and viscosity followed immediately by the next step. The run time will vary somewhat among differ
40、ent instruments andprocedures. Times as low as 2 min 2 min and as high as 20 min 20 min have been utilized successfully to run this test method.12.1.7 Run decreasing stress or rate sweep for duration of approximately 10 min 10 min to generate data of shear stress, shearrate, and viscosity.12.1.8 Cle
41、an sample from instrument in accordance with the manufacturers instructions. Cone and plate systems shall be rinsedwith a suitable solvent followed by wiping with a rag or towel.13. Calculation or Interpretation of Results13.1 Analyze the increasing and decreasing sweeps separately.13.2 Import the s
42、hear stress (Pa), shear rate (s-1) and viscosity (mPas) into a spreadsheet program. This calculation may be donewith a calculator. Delete data below the noise limit as determined in 10.3.13.3 Calculate two additional columns for ln (shear rate) and ln (shear stress). See Appendix X1 for sample calcu
43、lation.13.4 Plot the ln stress versus ln rate columns as a scatter plot with 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 26. There is nocriterion for correlation coefficient of candidate oils. See Appendix X
44、1 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-1 by interpolation between two data points spanning 100 s-1 as follows:VIS1005VIS11D 1002T1! (7)where:w
45、here:D = (VIS2 VIS1)/(T2 T1),5 The sole source of supply of the calibration fluid known to the committee at this time is Cannon Instrument Co., P.O. Box 16, State College, PA 16804. If you are awareof alternative suppliers, please provide this information toASTM International Headquarters.Your comme
46、nts will receive careful consideration at a meeting of the responsibletechnical committee,1 which you may attend.D6895 175VIS2 and T2 = viscosity and shear rate respectively at the first data point above 100 s-1, andVIS1 and T1 = viscosity and shear rate respectively at the first data point below 10
47、0 s-1.14. Report14.1 Report the rate index value as c, the viscosity as VIS100 and intercept as ln b . Label increasing and decreasing sweep datausing 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
48、places, x.xxxx.15. Precision6,715.1 Precision was found to be dependent on the mean value of the measured property.The data in this section was derived froma six laboratory/six sample interlaboratory study and a three laboratory/seven sample interlaboratory study. All data was pooledto generate the
49、repeatability and reproducibility data. VIS100 range was 14.99 to 36.28 mPas and rate index range was 0.623 to1.002.r RRate 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 + 0.168yVIS100, 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 : Calculations:15.2.1 The maximum value for rate index is 1.000. This occurs for fluid
