ASTM_D_5483_-_05_2015.pdf

Designation:D548305(Reapproved 2015)Standard Test Method forOxidation Induction Time of Lubricating Greases byPressure Differential Scanning Calorimetry1This standard is issued under the fixed designation D5483;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 test method covers the determination of oxidationinduction time of lubricating greases subjected to oxygen at3.5 MPa(500 psig)and temperatures between 155 C and210 C.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and Rhe-ology3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 extrapolated onset time,na time determined on athermal curve,as the intersection of the extrapolated baselineand a line tangent to the oxidation exotherm constructed at itsmaximum rate.3.1.2 oxidation induction time(OIT),n the period of timefrom the first exposure to an oxidizing atmosphere until theextrapolated onset time.3.1.3 pressure differential scanning calorimeter,(PDSC),na differential scanning calorimeter,as defined in Terminol-ogy E473,that is capable of maintaining the test sample at acontrolled,elevated pressure.3.1.4 thermal curve,na graph of sample heat flow versustime.4.Summary of Test Method4.1 A small quantity of grease is weighed into a sample panand placed in a test cell.The cell is heated to a specifiedtemperature and then pressurized with oxygen.The cell is heldat a regulated temperature and pressure until an exothermicreaction occurs.The extrapolated onset time is measured andreported as the oxidation induction time for the grease underthe specified test temperature.4.2 A kinetic equation incorporated with this test methodcan estimate oxidation induction times at other temperatures.5.Significance and Use5.1 Oxidation induction time,as determined under theconditions of this test method,can be used as an indication ofoxidation stability.3This test method can be used for researchand development,quality control and specification purposes.However,no correlation has been determined between theresults of this test method and service performance.6.Apparatus6.1 Pressure Differential Scanning Calorimeter(PDSC),equipped with the following items(see Fig.1).4NOTE1At the time that the round robin data for this test method wasgenerated,only TA Instruments4manufactured equipment that met therequirements of 5.1.Subsequently,other companies have manufacturedequipment meeting these requirements.Their use is permitted providedtheir performance is consistent with the repeatability and reproducibilitydescribed in Section 10.6.1.1 Sample Enclosure,with capability to 3.5 MPa(500 psig)at 210 C and pressure gauge graduated at intervalsof 200 kPa(28.6 psi)or less.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.09.0E on Oxidation of Greases.Current edition approved Oct.1,2015.Published December 2015.Originallyapproved in 1993.Last previous edition approved in 2010 as D5483 05(2010).DOI:10.1520/D5483-05R15.2For 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.3Rhee,In-Sik,“Development of a New Oxidation Stability Test Method forGreases Using a Pressure Differential Scanning Calorimeter(PDSC),”NLGISpokesman,Vol 55,No.4,July 1991,pp.123132.4The sole source of supply of the apparatus known to the committee at this timeis TAInstruments,Inc.,109 Lukens Drive,New Castle,DE 19720.If you are awareof alternative suppliers,please provide this information to ASTM InternationalHeadquarters.Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2 Thermal Analyzer.6.3 Aluminum Sample Solid Fat Index(SFI),pan(see Note2).6.4 Oxidation Stability Software.6.5 Calibration Software.6.6 Flowmeter,with a capacity of at least 200 mL min.6.7 Sample Encapsulation Press.NOTE2It has been found that grease samples can be prepared withmore consistent surface areas using SFI pans as compared to flat bottompans,resulting in better reproducib