1、Designation: D8206 18Standard Test Method forOxidation Stability of Lubricating GreasesRapid Small-Scale Oxidation Test (RSSOT)1This standard is issued under the fixed designation D8206; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, 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 quantitative determinationof the oxidation stability of lubricating grease
3、s with a droppingpoint above the test temperature.1.2 This test method determines the resistance of lubricatinggreases to oxidation when stored statically in an oxygenatmosphere in a sealed system at an elevated temperature underconditions of test.1.3 The values stated in SI units are to be regarded
4、 as thestandard. No other units of measurement are included in thisstandard.1.4 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, health, and environmental pract
5、ices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and
6、 Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D942 Test Method for Oxidation Stability of LubricatingGreases by the Oxygen Pressure Vessel MethodD4057 Practice for Manual Sampling of Petroleum andPetrole
7、um ProductsD6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricants2.2 ISO Standard:3EN 60751:2008 Industrial platinum resistance thermometersand platinum temperature3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1
8、break point, npressure in the test instrument, whichis 10 % below the maximum pressure of the actual test run.3.1.2 induction period, ntime elapsed between starting theheating procedure of the pressure vessel and the break point,measured in minutes.4. Summary of Test Method4.1 For this test, 4.00 g
9、6 0.01 g of sample is weighed in aglass dish at a temperature of 20 C 6 5 C and thenintroduced into a pressure vessel, which is subsequentlycharged with oxygen to 700 kPa 6 5 kPa.4.1.1 The test is initiated by heating the pressure vessel to atemperature of 140 C 6 0.5 C or 160 C 6 0.5 C, dependingon
10、 the selected test.4.2 The pressure is recorded continuously until the breakpoint is reached.5. Significance and Use5.1 This test method measures the net change in pressureresulting from consumption of oxygen by oxidation and gain inpressure due to formation of volatile oxidation by-products.This te
11、st method may be used for quality control to indicatebatch-to-batch uniformity. It predicts neither the stability ofgreases stored in containers for long periods, nor the stabilityof films of greases on bearings and motor parts.5.2 Induction period as determined under the conditions ofthis test meth
12、od can be used as an indication of oxidationstability. This test method can be used for research anddevelopment, quality control, and specification purposes.However, no correlation has been determined between theresults of this test method and service performance.1This test method is under the juris
13、diction 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 June 1, 2018. Published July 2018. DOI: 10.1520/D8206-18.2For referenced ASTM standards, visit the ASTM website,
14、 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 American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/ww
15、w.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopme
16、nt of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16. Apparatus6.1 GeneralThis test method uses an automatically con-trolled oxidation tester4(see Fig. 1), comprising a pressurevessel capable of being heated q
17、uickly and fitted with apressure sensor capable of measuring pressures up to 1800 kPaand a temperature sensor capable of reading to 0.1 C accuracy.Pressure and temperature in the pressure vessel are recordedcontinuously during the test. The pressure vessel is fitted withoxygen inlet and outlet valve
18、s and a means of automaticallyreleasing the pressure at the end of the test. The integratedcooling fan cools the pressure vessel from the test temperatureto ambient temperature by a flow of air. See Annex A1 fordetailed information.6.2 Analytical Balance, with a resolution of 60.001 g.6.3 Glass Dish
19、 (see Fig. 3)A borosilicate glass dish witha diameter of 41 mm 6 1 mm and a height of 8 mm 6 0.9 mm(according to Test Method D942; see Fig. A1.1).6.4 Temperature Calibration Equipment (see Fig. 4), com-prising a cover and a calibrated temperature sensor. Thecalibrated temperature sensor is fixed to
20、a depth of 15 mm 60.5 mm. The temperature sensor is calibrated to the nearest0.1 C by an approved calibration service, such as one that istraceable to the National Institute of Standards and Technology(NIST) or to a national authority in the country in which theequipment is used or manufactured.6.5
21、Pressure Calibration Equipment (see Fig. 5), compris-ing a calibrated pressure sensor. The pressure sensor is cali-brated to the nearest 10 kPa, by an approved calibrationservice, such as one that is traceable to the National Institute ofStandards and Technology (NIST) or to a national authority int
22、he country in which the equipment is used or manufactured.7. Reagents and Materials7.1 Purity of ReagentsReagent-grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American
23、 Chemical Society wheresuch specifications are available.5Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.4The sole source of supply of the instrument known to the committee
24、at this timeis Anton Paars RapidOxy instrument, available from Anton Paar ProveTec GmbH,Ludwig-Erhard-Ring 13, 15827 Blankenfelde-Mahlow, Germany, www.anton-. If you are aware of alternative suppliers, please provide this informationto ASTM International Headquarters. Your comments will receive care
25、ful consid-eration at a meeting of the responsible technical committee,1which you may attend.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Stand
26、ards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Example of RSSOT InstrumentD8206 1827.2 EthanolMinimum purity 94 %. A solvent for theremoval of oxidation residues fr
27、om the pressure vessel has tobe used. Commercially available ethanol of 94 % minimumpurity has been found to be suitable to remove residues fromthe test vessel.7.3 Cleaning SolutionA laboratory liquid, alkaline high-performance concentrated cleaner for immersion and ultrasonicbaths, diluted in water
28、 to the manufacturers recommendationand capable of satisfactorily cleaning the glassware used in thetest. (WarningDanger! Wear protective gloves/eye protec-tion. May cause skin irritation or serious eye damage.)7.4 Oxygen, of not less than 99.5 % purity. (WarningDanger! Since oxygen vigorously accel
29、erates combustion,observe the following procedures: (1) Keep oil and greaseaway from oxygen at high pressure. Keep oil and grease awayfrom all regulators, gauges, and control equipment. (2) Useoxygen only with equipment conditioned for oxygen service bycareful cleaning to remove oil and grease from
30、area in contactwith high-pressure oxygen. (3) Keep combustibles away fromoxygen and eliminate ignition sources. (4) Keep surfaces cleanto prevent ignition or explosion, or both, upon contact withhigh pressure oxygen. (5) Always use a pressure regulator todeliver oxygen. Release regulator tension bef
31、ore openingoxygen cylinder. (6) All equipment must be suitable andrecommended for oxygen service.)7.5 Lint-Free Cleaning TissueSuitable for sensitivesurfaces, that will not scratch the surface.7.6 O-Ring Seal (see A1.2)Made of material being resis-tant to oxygen and heat, typically fluoro-elastomer
32、FPM/FKMcoated with polytetrafluoroethylene (PTFE).7.7 Temperature Calibration FluidStable middle distillatefuel liquid with a flash point above 60 C and boiling pointabove 170 C. (WarningFlammable. Keep away from heatand open flame. Keep container closed. Use with adequateventilation. Avoid prolonge
33、d or repeated contact with skin.)NOTE 1Any hydrocarbon fuel with sufficient stability and a knowninduction period may be used as a verification fluid. In general, verifica-tion fluid with a certified induction period is available from the manufac-turer of the instrument.8. Hazards8.1 To provide prot
34、ection against the possible explosiverupture of the pressure vessel, the instrument shall be operatedbehind an appropriate safety shield or hood sash.9. Sampling9.1 Sample in accordance with Practice D4057. The samplepresented for analysis should be large enough to make possiblethe selection of a re
35、presentative portion for testing. Examinefor any indication of non-homogeneity such as oil separation,phase changes, or gross contamination. If any abnormalconditions are found, obtain a new sample.10. Preparation of Instrument10.1 From the previous run, remove the glass dish from thepressure vessel
36、 using tongs or forceps.FIG. 2 Example of Rear View of Instrument with Oxygen Inlet and Outlet ValveFIG. 3 Glass Dish (sample container)NOTE 1All dimensions are in millimetres.D8206 18310.2 Wipe the pressure vessel, the seal groove, and thescrew cap of the pressure vessel with lint-free cleaning tis
37、sue(see 7.5) soaked with ethanol until free of gum or otheroxidation residues.10.3 Thoroughly clean the glass dish by removing thegrease first mechanically and then by using the cleaningsolution (see 7.3). Follow the final cleaning by a tap waterrinse, a distilled water rinse, and drying in an oven.
38、 Handle theclean dishes only with forceps.10.4 Allow the test sample cup and cover to dry in air andvisually inspect for cleanliness.NOTE 2Compressed air is generally unsuitable to speed up evapora-tion of solvent because it can contain traces of oil that could contaminatethe next test.10.5 Anew O-r
39、ing seal must be used for each test to preventcontamination from the previous test.11. Calibration11.1 Check the instrument regularly and according to yourlaboratorys specifications with suitable reference material.Pressure and temperature are critical parameters. Proper cali-bration of the respecti
40、ve sensors is therefore important. Rec-ommended interval for temperature and pressure calibration is12 months.11.2 Calibration of Temperature SensorCalibrate the tem-perature sensor to the nearest 0.1 C using the temperaturecalibration equipment according to A2.1.FIG. 4 Temperature Calibration Equip
41、ment1. Calibration cover with duct for temperature calibration sensor2. Calibration fluid3. Temperature sensor for block temperature4. Heating block5. Immersion depth of temperature calibration sensor and bottom of calibration cover6. Seal7. Temperature calibration sensor8. Connector plug to measuri
42、ng deviceNOTE 1All dimensions are in millimetres.D8206 18411.3 Calibration of Pressure SensorCalibrate the pressuresensor to the nearest 10 kPa using the pressure calibrationequipment according to A2.2.12. Procedure12.1 Using a balance, weigh 4.00 g 6 0.01 g of the sampleinto the glass dish. Distrib
43、ute the sample in the dish in auniform layer with a smooth level upper surface.12.2 Switch on the instrument and set the test temperatureaccording to the manufacturers instructions.12.3 Place the filled glass dish into the pressure vessel usingforceps.12.4 Allow the pressure vessel and the glass dis
44、h with thelubricating grease sample to adapt to a temperature of 20 C 65 C.12.5 Close the pressure vessel with the screw cap.12.6 Introduce oxygen into the pressure vessel until apressure of 700 kPa 6 5 kPa is attained and stabilized. Thisshould take no more than 3 min.12.6.1 Release the oxygen from
45、 the pressure vessel to flushout the air originally present. Introduce oxygen again until apressure of 700 kPa 6 5 kPa is attained and stabilized.12.7 Start the heater with no delay between charging withoxygen and starting the test. The instrument automaticallystarts the timer when the heating proce
46、ss begins.12.8 The instrument heats the test vessel and specimen tothe test temperature.12.9 If, during the initial 5 min of the test, a steady drop inpressure is observed, discontinue the test and discard the testspecimen.FIG. 5 Pressure Calibration EquipmentD8206 18512.9.1 Check the leakage rate a
47、ccording to the manufactur-ers instructions. The leakage rate shall not exceed a value of2 kPa/h at 140 C.12.10 The instrument automatically records the testduration, test temperature (to the nearest 0.1 C), and testpressure (to the nearest 1 kPa) of the oxidation vessel continu-ously.12.11 The inst
48、rument will automatically terminate the testwhen the pressure has dropped 10 % below the maximumobserved pressure. This is the break point.12.12 The instrument automatically records the inductionperiod to the nearest 0.01 min.NOTE 3The instrument will automatically switch on the fan to coolthe press
49、ure vessel to approximately room temperature. When the instru-ment has cooled sufficiently, the instrument automatically releases thepressure slowly from the pressure vessel through the oxygen outlet valve.12.13 When the pressure release process has finished, openthe instrument and clean according to Section 10.13. Report13.1 Report the induction period to the nearest wholeminute and reference this test method and the test temperatureapplied.14. Precision and Bias14.1 PrecisionThe following precision was determined inaccordance
