ASTM_D_6080_-_12a.pdf

Designation:D608012aStandard Practice forDefining the Viscosity Characteristics of Hydraulic Fluids1This standard is issued under the fixed designation D6080;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.Scope*1.1 This practice covers all hydraulic fluids based either onpetroleum,synthetic,or naturally-occurring base stocks.It isnot intended for water-containing hydraulic fluids.1.2 For determination of viscosities at low temperature,thispractice uses millipascalsecond(mPas)as the unit of viscos-ity.For reference,1 mPas is equivalent to 1 centipoise(cP).For determination of viscosities at high temperature,thispractice uses millimetre squared per second(mm2/s)as the unitof kinematic viscosity.For reference,1 mm2/s is equivalent to1 centistoke(cSt).1.3 This practice is applicable to fluids ranging in kinematicviscosity from about 4 to 150 mm2/s as measured at a referencetemperature of 40C and to temperatures from 50 to+16Cfor a fluid viscosity of 750 mPas.NOTE1Fluids of lesser or greater viscosity than the range describedin 1.3 are seldom used as hydraulic fluids.Any mathematical extrapolationof the system to either higher or lower viscosity grades may not beappropriate.Any need to expand the system should be evaluated on itsown merit.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.2.Referenced Documents2.1 ASTM Standards:2D445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids(and Calculation of Dynamic Viscos-ity)D2270 Practice for Calculating Viscosity Index from Kine-matic Viscosity at 40 and 100CD2422 Classification of Industrial Fluid Lubricants by Vis-cosity SystemD2983 Test Method for Low-Temperature Viscosity of Lu-bricants Measured by Brookfield ViscometerD5621 Test Method for Sonic Shear Stability of HydraulicFluidsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2.2 Society of Automotive Engineers(SAE)Standards:3J300 Engine Oil Viscosity ClassificationJ306 Axle and Manual Transmission Lubricant ViscosityClassification3.Terminology3.1 Definitions:3.1.1 hydraulic fluid,na liquid used in hydraulic systemsfor lubrication and transmission of power.3.1.2 kinematic viscosity,nthe ratio of the dynamic vis-cosity to the density of a liquid.3.1.2.1 DiscussionFor gravity flow under a given hydro-static head,the pressure head of a liquid is proportional to itsdensity.Therefore,kinematic viscosity is a measure of theresistance to flow of a liquid under gravity.3.1.3 Newtonian oil or fluid,nan oil or fluid that at a giventemperature exhibits a constant viscosity at all shear rates orshear stresses.3.1.4 non-Newtonian oil or fluid,nan oil or fluid that at agiven temperature exhibits a viscosity that varies with chang-ing shear stress or shear rate.3.1.5 shear degradation,nthe decrease in molecularweight of a polymeric thickener(VI improver)as a result ofexposure to high shear stress.3.1.6 shear rate,nthe velocity gradient in fluid flow.3.1.7 shear stability,nthe resistance of a polymer-thickened fluid to shear degradation.3.1.8 shear stress,nthe motivating force per unit area forfluid flow.3.1.9 viscosity,nthe ratio between the applied shear stressand the rate of shear.1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts,Liquid Fuels,and Lubricants and is the direct responsibility of Subcom-mittee D02.N0.10 on Specifications.Current edition approved Nov.1,2012.Published February 2013.Originallyapproved in 1997.Last previous edition approved in 2012 as D608012.DOI:10.1520/D6080-12A.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.3Available from Society of Automotive Engineers(SAE),400 CommonwealthDr.,Warrendale,PA 15096-0001,http:/www.sae.org.*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 States1 3.1.9.1 DiscussionViscosity is sometimes called the coef-ficient of dynamic viscosity.This coefficient is a measure of theresistance to flow of the liquid.3.1.10 viscosity index(VI),nan arbitrary number used tocharacterize the variation of the kinematic viscosity of a fluidwith temperature.3.2 Definitions of Terms Specific to This Standard:3.2.1 in-service viscosity,nthe viscosity of fluid duringoperation of a hydraulic pump or circuit components.4.Summary of Practice4.1 High VI hydraulic fluids often contain high molecularweight thickeners,called viscosity index(VI)improvers,which impart non-Newtonian char