1、Designation: D 6022 06An American National StandardStandard Practice forCalculation of Permanent Shear Stability Index1This standard is issued under the fixed designation D 6022; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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.1. Scope*1.1 This practice specifies the procedure for the calculationof Permanent Shear Stability Index (PSSI) of an add
3、itive usingviscosities before and after a shearing procedure.1.2 PSSI is calculated for a single blend component and canthen be used to estimate the effects of that component onfinished lubricant blends.1.3 This practice is applicable to many products and mayuse data from many different test methods
4、. The calculation ispresented in its most general form in order not to restrict itsuse.2. Referenced Documents2.1 ASTM Standards:2D 2603 Test Method for Sonic Shear Stability of Polymer-Containing OilsD 4485 Specification for Performance of Engine OilsD5119 Test Method for Evaluation of Automotive E
5、ngineOils in the CRC L-38 Spark-Ignition Engine3D 5275 Test Method for Fuel Injector Shear Stability Test(FISST) for Polymer Containing FluidsD 5621 Test Method for Sonic Shear Stability of HydraulicFluidsD 6278 Test Method for Shear Stability of Polymer Con-taining Fluids Using a European Diesel In
6、jector ApparatusD 7109 Test Method for Shear Stability of Polymer Con-taining Fluids Using a European Diesel Injector Apparatusat 30 and 90 Cycles2.2 CEC Standards:4CEC L14A 93 Evaluation of the Mechanical Shear Stabilityof Lubricating Oils Containing PolymersCEC L37 T 85 Shear Stability of Polymer-
7、Containing Oils(FZG)CEC L45 T 93 Viscosity Shear Stability of TransmissionLubricants (KRL)3. Terminology3.1 Definitions:3.1.1 degree of thickening (DT), nthe ratio of an oilsviscosity with an additive to that oils viscosity without theadditive. A measure of the amount by which an additiveincreases t
8、he base fluid viscosity.3.1.2 permanent shear stability index (PSSI), na measureof the irreversible decrease, resulting from shear, in an oilsviscosity contributed by an additive.3.1.2.1 DiscussionPSSI is a property calculated for asingle component. Viscosity Loss (q.v.) is a property measuredfor a
9、finished oil.3.1.3 shear, adja relative movement of molecules ormolecular aggregates that occurs in flowing liquids. A shearflow is one in which the spatial velocity gradient is perpen-dicular to the direction of flow.3.1.3.1 DiscussionNot all flow geometries meet this defi-nition.3.1.4 shear, vto s
10、ubject a liquid to a shear flow.3.1.4.1 DiscussionShearing an oil can sometimes causescission of certain molecular species, resulting in a decrease inviscosity. Not all oils exhibit this response. Common ways ofshearing oils to elicit this effect include injection through asmall orifice and flow thr
11、ough gears or bearings. Irradiationwith sonic energy can also decrease the viscosity of some oils.3.1.5 Viscosity Loss (VL), na measure of the decrease inan oils viscosity.3.1.5.1 DiscussionViscosity Loss is a property measuredfor a finished oil. Permanent Shear Stability Index (q.v.)isaproperty cal
12、culated for a single component. Some test methodsreport VL as a relative change, which is dimensionless (forexample, Test Methods D 2603, D 5275, D 6278, and D 7109).Some test methods and specifications report VL as an absolutechange, which has the same dimensions as the viscosity1This practice is u
13、nder the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct responsibility of Subcommittee D02.07 onFlow Properties.Current edition approved May 1, 2006. Published May 2006. Originallyapproved in 1996. Last previous edition approved in 2001 as D 602201.2For refe
14、renced 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.3Withdrawn.4Available from Organization for Economic Cooperation and D
15、evelopment,Madou Plaza, Place Madou 1, B-1030 Brussels, Belgium.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.measurements (for example, Specification D 4485 and Tes
16、tMethods D5119and D 5621).3.2 Definitions of Terms Specific to This Standard:3.2.1 base fluid, nan oil without the additive whose PSSIis to be determined. The base fluid shall have a viscosity lossof zero, within the precision of the shearing test used.3.2.1.1 DiscussionA base fluid could be a miner
17、al oil, asynthetic oil, a formulation containing additives, or othersystem meeting the requirement of zero viscosity loss.3.2.2 sheared oil, nthe test oil, after shearing.3.2.3 test oil, nbase fluid with the additive whose PSSI isto be determined.3.2.4 unsheared oil, nthe test oil, prior to shearing
18、.4. Summary of Practice4.1 An index is calculated representing the change, due toshearing, in an additives contribution to a lubricants viscosity.A low index represents high resistance to permanent change.4.2 Oils can be sheared by many means, including benchtests designed for that purpose, engine t
19、ests, and field service.A PSSI can be calculated for each. These indices can be usedto compare the shearing severity of each test.NOTE 1Some methods, especially engine tests and field service, mayinclude conditions where other effects (for example, evaporative loss,oxidation, fuel dilution, soot acc
20、umulation, and so forth.) contribute toviscosity changes. The PSSI calculated from these types of service maynot be representative of pure shearing.4.2.1 ASTM tests commonly used to shear oils include TestMethods D 2603, D 5275, D 5621, D 6278, and D 7109,among others.4.2.2 Other standards organizat
21、ions publish test methodswhich may be suitable for shearing oils.54.2.3 An engine test, Test Method D5119, is also com-monly used to shear oils and establish a PSSI for additives.5. Significance and Use5.1 Permanent Shear Stability Index (PSSI) is a measure ofthe loss of viscosity, due to shearing,
22、contributed by a specifiedadditive.NOTE 2For example, a PSSI of 50 means the additive will lose 50 %of the viscosity it contributes to the finished oil.5.2 The selection of appropriate base fluids and additiveconcentrations to be used in test oils is left to individualoperators or companies. These c
23、hoices will depend on theintended application for the additive.NOTE 3PSSI may depend more strongly on base fluid, additiveconcentration, additive chemistry, and the presence of other additives forbase fluids of unusual composition (for example, esters) or if additivesoutside the common range of chem
24、istries and concentrations are used.Caution should be exercised when interpreting results from differentsources.6. Procedure6.1 Calculate the degree of thickening:DT 5 V0/Vb(1)where:V0= viscosity of the unsheared oil, andVb= viscosity of the base fluid.6.1.1 Viscosities shall be measured using the s
25、ame testmethod at the same conditions of temperature and shear rate orshear stress and reported in the same units.6.2 If the degree of thickening is less than 1.2, PSSI cannotbe determined from these data.NOTE 4Once PSSI has been determined for an additive, calculationsusing that PSSI can be made fo
26、r oil blends where the degree of thickeningis less than 1.2.6.3 If the degree of thickening is greater than or equal to 1.2,calculate PSSI using the equation:PSSI 5 100 3 V0 Vs!/V0 Vb! (2)where:PSSI = Permanent Shear Stability Index,V0= viscosity of the unsheared oil,Vs= viscosity of the sheared oil
27、, andVb= viscosity of the base fluid.6.3.1 Viscosities shall be measured using the same testmethod at the same conditions of temperature and shear rate orshear stress and reported in the same units.NOTE 5If Vbis close in value to V0, that is if the degree of thickeningis small, the denominator in Eq
28、 2 approaches zero, and the precision ofPSSI becomes unacceptable. A minimum degree of thickening of 1.2 waschosen to avoid meaningless calculations of PSSI.6.3.2 For example, an additive is added to a base fluid ofkinematic viscosity 10 mm2/s at 100C, resulting in an un-sheared oil kinematic viscos
29、ity of 15 mm2/s at 100C. After ashearing test, the sheared oil has a viscosity of 13 mm2/s at100C. The PSSI of the additive is calculated as:DT 5 15/10 5 1.5 . 1.2 (3)PSSI 5 100 3 1513!/15 10! 5 100 3 2/5! 5 40 (4)6.4 Re-arranging Eq 2 gives other useful relationships. Theviscosity of a formulation,
30、 after shearing, could be estimatedas:Vs5 V0 PSSI/100! 3 V0 Vb! (5)orVs5 V01 PSSI/100! 1 Vb3 PSSI/100! (6)and the viscosity of the unsheared oil is:V05 Vs Vb3 PSSI/100!#/1 PSSI/100!# (7)6.4.1 For example, using an additive with a PSSI of 50 anda base oil of kinematic viscosity 8 mm2/s, it is desired
31、 to havea sheared oil of no less than 12 mm2/s. To what kinematicviscosity should the unsheared oil be blended?V05 Vs Vb3 PSSI/100!#/1 PSSI/100!# (8)5 128!0.5!#/1 0.5 5 16NOTE 6The PSSI of the additive must be determined using the sameshearing test method as the specification to be met.7. Report7.1
32、If the degree of thickening is less than 1.2, report PSSIcannot be determined by this practice.5CEC L14A 93, CEC L37T 85, and CEC L45T 93, for example.D60220627.2 If the degree of thickening is greater than or equal to 1.2,report the calculated PSSI to the nearest whole number, the testmethod used f
33、or shearing, the test method used to measureviscosity, the identity of the base fluid, and the degree ofthickening.8. Precision and Bias8.1 The calculation of PSSI is exact, and no precision limitscan be assigned to this calculation.8.2 The accuracy of calculated PSSI will depend on theprecision of
34、the viscosity determinations and the precision ofthe shearing method.8.3 See Appendix X1 for a discussion of the expectedvariation in PSSI.8.4 BiasThe calculation of Permanent Shear StabilityIndex is exact, and no bias can be assigned to this calculation.9. Keywords9.1 permanent shear stability inde
35、x; shear; shear stabilityindex; viscosity lossAPPENDIX(Nonmandatory Information)X1. EXPECTED VARIATION IN SHEAR STABILITY INDEX CALCULATIONSX1.1 Although the calculation of PSSI is exact, given theinput data, that input data can vary for repeat determinations ona single sample. This variation can pr
36、opagate into the calcula-tion of PSSI.X1.2 If two operators are given the same raw data ofviscosities, they will calculate the same PSSI.X1.3 If two operators are given samples of the sameunsheared oil, sheared oil, and base fluid for the determinationof PSSI, their results are expected to differ du
37、e to the finiteprecision of viscosity determinations. Standard formulae forthe propagation of errors6suggest the resultant relative error inPSSI will be approximately twice the relative error of theviscosity measurements. For example, if the reproducibility ofeach viscosity measurement is 0.7 % of i
38、ts mean, the expectederror of PSSI is approximately 1.4 % of its mean.NOTE X1.1The relative errors of the three kinematic viscosity mea-surements introduce a factor of approximately =3 into the relative errorof PSSI. To the nearest whole number, this will be two times the relativeerror of a single k
39、inematic viscosity test result.X1.4 If two operators are given samples of unsheared oiland base fluid to conduct a shearing test and subsequentdetermination of PSSI, their results are expected to vary due tothe precision of the shearing test as well as the precision of theviscosity determinations. S
40、tandard formulae for the propaga-tion of errors6suggest the resultant relative error in PSSI willbe approximately the sum of the relative errors of a singleviscosity measurement and the relative error of viscosity lossfrom shearing method. For example, if the reproducibility ofthe base fluid viscosi
41、ty measurement is 0.7 % of the mean andthe reproducibility of viscosity loss in the shearing method is5.22 %, the expected error of PSSI is approximately 6 %.SUMMARY OF CHANGESSubcommittee D02.07 has identified the location of selected changes to this standard since the last issue(D 602201) that may
42、 impact the use of this standard.(1) Deleted reference to Test Method D 3945.(2) Added Test Method D 7109.(3) Changed reference to Test Method D 5621 from relative toabsolute.6Ku, H. H., “Notes on the Use of Propagation of Error Formulas,” Journal ofResearch of the National Bureau of StandardsC. Eng
43、ineering and Instrumenta-tion, Vol 70C, No. 4, pp. 331341, OctoberDecember 1966.D6022063ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of
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46、nts have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D6022064
