1、Designation: D6022 06 (Reapproved 2012)Standard Practice forCalculation of Permanent Shear Stability Index1This standard is issued under the fixed designation D6022; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice specifies the procedure for the calculationof Permanent Shear Stability Index (PSSI) of an additive usingvisc
3、osities 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. The calculati
4、on ispresented in its most general form in order not to restrict itsuse.2. Referenced Documents2.1 ASTM Standards:2D2603 Test Method for Sonic Shear Stability of Polymer-Containing OilsD4485 Specification for Performance of Active API ServiceCategory Engine OilsD5119 Test Method for Evaluation of Au
5、tomotive EngineOils in the CRC L-38 Spark-Ignition Engine (Withdrawn2003)3D5275 Test Method for Fuel Injector Shear Stability Test(FISST) for Polymer Containing FluidsD5621 Test Method for Sonic Shear Stability of HydraulicFluidsD6278 Test Method for Shear Stability of Polymer Contain-ing Fluids Usi
6、ng a European Diesel Injector ApparatusD7109 Test Method for Shear Stability of Polymer Contain-ing Fluids Using a European Diesel Injector Apparatus at30 and 90 Cycles2.2 CEC Standards:4CEC L14A 93 Evaluation of the Mechanical Shear Stabilityof Lubricating Oils Containing PolymersCEC L37 T 85 Shear
7、 Stability of Polymer-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
8、an additiveincreases the 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 p
9、roperty measuredfor a 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-nit
10、ion.3.1.4 shear, vto subject 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 asmal
11、l orifice and flow through 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
12、 (q.v.)isaproperty calculated for a single component. Some test methodsreport VL as a relative change, which is dimensionless (forexample, Test Methods D2603, D5275, D6278, and D7109).1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct
13、 responsibility of Subcommittee D02.07 onFlow Properties.Current edition approved Nov. 1, 2012. Published November 2012. Originallyapproved in 1996. Last previous edition approved in 2006 as D602206. DOI:10.1520/D6022-06R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcont
14、act ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from Organization for Economic Cooperation
15、 and Development,Madou Plaza, Place Madou 1, B-1030 Brussels, Belgium.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Some test methods and specifications report VL as an absolutechange, which has the same dimensions as the viscositym
16、easurements (for example, Specification D4485 and TestMethods D5119 and D5621).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
17、 used.3.2.1.1 DiscussionA base fluid could be a mineral 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.
18、3.2.4 unsheared oil, nthe test oil, prior to shearing.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, inc
19、luding benchtests designed for that purpose, engine tests, 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
20、, evaporative loss,oxidation, fuel dilution, soot accumulation, 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 D2603, D5275, D5621, D6278, and D7
21、109, amongothers.4.2.2 Other standards organizations publish test methodswhich may be suitable for shearing oils.54.2.3 An engine test, Test Method D5119, is also commonlyused to shear oils and establish a PSSI for additives.5. Significance and Use5.1 Permanent Shear Stability Index (PSSI) is a meas
22、ure ofthe loss of viscosity, due to shearing, 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 lef
23、t to individualoperators or companies. These choices 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) o
24、r if additivesoutside the common range of chemistries 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
25、.1.1 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.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 additi
26、ve, calculationsusing that PSSI can be made for 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 V02 Vs!/V02 Vb! (2)where:PSSI = Permanent Shear Stability Index,V0= viscosity of th
27、e unsheared oil,Vs= viscosity of the sheared oil, 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 deg
28、ree of thickeningis small, the denominator in Eq 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,
29、 resulting in an un-sheared oil kinematic viscosity 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 15 2 13!/15 2 10! 5 100 3 2/5! 5 40 (4)6.4 Re-arranging Eq 2 gives other u
30、seful relationships. Theviscosity of a formulation, after shearing, could be estimatedas:Vs5 V02 PSSI/100! 3 V02 Vb! (5)orVs5 V01 2 PSSI/100!1Vb3 PSSI/100! (6)and the viscosity of the unsheared oil is:V05 Vs2 Vb3 PSSI/100!#/1 2 PSSI/100!# (7)6.4.1 For example, using an additive with a PSSI of 50 and
31、a base oil of kinematic viscosity 8 mm2/s, it is desired to havea sheared oil of no less than 12 mm2/s. To what kinematicviscosity should the unsheared oil be blended?V05 Vs2 Vb3 PSSI/100!#/1 2 PSSI/100!# (8)5128!0.5!#/1 2 0.5# 5 165CEC L14A 93, CEC L37T 85, and CEC L45T 93, for example.D6022 06 (20
32、12)2NOTE 6The PSSI of the additive must be determined using the sameshearing test method as the specification to be met.7. Report7.1 If the degree of thickening is less than 1.2, report PSSIcannot be determined by this practice.7.2 If the degree of thickening is greater than or equal to 1.2,report t
33、he calculated PSSI to the nearest whole number, the testmethod used for 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 calculatio
34、n.8.2 The accuracy of calculated PSSI will depend on theprecision of 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 assig
35、ned to this calculation.9. Keywords9.1 permanent shear stability index; 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 va
36、ry for repeat determinations ona single sample. This variation can propagate 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
37、for the determinationof PSSI, their results are expected to differ due 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 examp
38、le, if the reproducibility ofeach viscosity measurement is 0.7 % of its mean, the expectederror of PSSI is approximately 1.4 % of its mean.NOTE X1.1The relative errors of the three kinematic viscositymeasurements introduce a factor of approximately 3 into the relativeerror of PSSI. To the nearest wh
39、ole number, this will be two times therelative error of a single kinematic 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 sheari
40、ng test as well as the precision of theviscosity determinations. Standard 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 me
41、thod. For example, if the reproducibility ofthe base fluid viscosity 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 %.ASTM International takes no position respecting the validity of any patent r
42、ights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at a
43、ny time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments
44、will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments 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
45、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);
46、 or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).6Ku, H. H., “Notes on the Use of Propagation of Error Formulas,” Journal ofResearch of the National Bureau of StandardsC. Engineering andInstrumentation, Vol 70C, No. 4, pp. 331341, OctoberDecember 1966.D6022 06 (2012)3
