ASTM_D_6022_-_06_2012.pdf

Designation:D602206(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 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 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.The calculation 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 Automotive 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 Using 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 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 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 property 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-nition.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 asmall 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(q.v.)is aproperty 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 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,orcontact 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 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 States1 Some test methods and specifications report VL as an absolutechange,which has the same dimensions as the viscositymeasurements(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 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