ASTM D7098-2008 781 Standard Test Method for Oxidation Stability of Lubricants by Thin-Film Oxygen Uptake (TFOUT) Catalyst B.pdf

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1、Designation: D 7098 08An American National StandardStandard Test Method forOxidation Stability of Lubricants by Thin-Film OxygenUptake (TFOUT) Catalyst B1, 2This standard is issued under the fixed designation D 7098; the number immediately following the designation indicates the year oforiginal adop

2、tion 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 test method covers the oxidation stability oflubricants by thin-fi

3、lm oxygen uptake (TFOUT) Catalyst B.This test method evaluates the oxidation stability of petroleumproducts, and it was originally developed as a screening test toindicate whether a given re-refined base stock could beformulated for use as automotive engine oil3(see Test MethodD 4742). The test is r

4、un at 160C in a pressure vessel underoxygen pressure, and the sample contains a metal catalystpackage, a fuel catalyst, and water to partially simulate oilconditions in an operating engine. In addition, the test methodhas since been found broadly useful as an oxidation test ofpetroleum products.41.2

5、 The applicable range of the induction time is from a fewminutes up to several hundred minutes or more. However, therange of induction times used for developing the precisionstatements in this test method was from 40 to 280 min.1.3 The values stated in SI units are to be regarded as thestandard. The

6、 values given in parentheses are for informationonly.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 and health practices and determine the applica-bility o

7、f regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:5A 314 Specification for Stainless Steel Billets and Bars forForgingB211 Specification for Aluminum and Aluminum-AlloyBar, Rod, and WireD 664 Test Method forAcid Number of Petroleum Productsby Potentiometric TitrationD 1

8、193 Specification for Reagent WaterD 2272 Test Method for Oxidation Stability of Steam Tur-bine Oils by Rotating Pressure VesselD 4742 Test Method for Oxidation Stability of GasolineAutomotive Engine Oils by Thin-Film Oxygen Uptake(TFOUT)E1 Specification for ASTM Liquid-in-Glass ThermometersE 144 Pr

9、actice for Safe Use of Oxygen Combustion Bombs3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 break pointthe precise point of time at which rapidoxidation of the oil begins.3.1.2 oxidation induction timethe time until the oil beginsto oxidize at a relatively rapid rate as indi

10、cated by the decreaseof oxygen pressure.3.1.3 oxygen uptakeoxygen absorbed by oil as a result ofoil oxidation.4. Summary of Test Method4.1 The test oil is mixed in a glass container with four otherliquids used to simulate engine conditions: (1) an oxidized/nitrated fuel component (Annex A3), (2) a m

11、ixture of solublemetal naphthenates (lead, iron, manganese, and tin naphthen-ates (Annex A4), (3) a nitro-paraffinic compound, and (4) TypeI reagent water.4.2 The glass container holding the oil mixture is placed ina pressure vessel equipped with a pressure sensor. The pressurevessel is sealed, char

12、ged with oxygen to a pressure of 620 kPa1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.09.0G on Oxidation Testing of Engine Oils.Current edition approved Oct. 15, 2008. Published November 2008.

13、 Originallyapproved in 2005. Last previous edition approved in 2006 as D 7098061.2While Catalyst B can be used for testing oxidation stability of many lubricanttypes, the mixture of fuel, nitro-paraffin, and catalyst components used in this testmethod simulates the Sequence IIIE Engine Test. Test re

14、sults on several ASTMreference oils have been found to correlate with Sequence IIIE engine tests in hoursfor a 375 % viscosity increase. (See Ku, Chia-Soon, Pei, Patrick T., and Hsu,Stephen M., “A Modified Thin-Film Oxygen Uptake Test (TFOUT) for theEvaluation of Lubricant Stability in ASTM Sequence

15、 IIIE Test, SAE TechnicalPaper Series 902121, Tulsa, OK, Oct. 22-25, 1990.)3Ku, C. S. and Hsu, S. M., “A Thin Film Uptake Test for the Evaluation ofAutomotive Lubricants,” Lubrication Engineering, 40, 2, 1984, pp. 7583.4Selby, Theodore W., “Oxidation Studies with a Modified Thin-Film OxygenUptake Te

16、st”, SAE Technical Paper Series 872127, Toronto, Ontario, Nov. 2-5,1987.5For 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 AS

17、TM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.(90 psig), and placed in an oil bath at 160C at an angle of 30from the horizontal. The pressure vessel is ro

18、tated axially at aspeed of 100 r/min forming a thin film of oil within the glasscontainer resulting in a relatively large oil-oxygen contact area.4.3 The pressure of the pressure vessel is recorded continu-ously from the beginning of the test and the test is terminatedwhen a rapid decrease of the pr

19、essure vessel pressure isobserved (Point B, Fig. 1). The period of time that elapsesbetween the time when the pressure vessel is placed in the oilbath and the time at which the pressure begins to decreaserapidly is called the oxidation induction time and is used as ameasure of the relative oil oxida

20、tion stability.5. Significance and Use5.1 This test method was originally developed to evaluateoxidation stability of lubricating base oils combined withadditives chemistries similar to those found in gasoline engineoils and service.25.2 This test method is useful for screening formulated oilsbefore

21、 engine tests. Within similar additive chemistries andbase oil types, the ranking of oils in this test appears to bepredictive of ranking in certain engine tests. When oils havingdifferent additive chemistries or base oil type are compared,results may or may not reflect results in engine tests. Only

22、gasoline engine oils were used in generating the precisionstatements in this test method.6. Apparatus6.1 Oxidation Bath and Pressure VesselSee appropriateAnnex (Annex A16or Annex A27) for detailed description ofapparatus and accessories for equipment described in this testmethod.NOTE 1To reduce vapo

23、r odors when opening pressure vessel afteruse, a hood may be desirable.6.2 Precision Pressure GaugeUse a certified precisionpressure gauge to accurately control the oxygen feed to thepressure vessel. The gauge shall have a sufficient range toencompass 0 to 650 kPa (90 psig) required by the test meth

24、odwith division 2.0 kPa (0.5 psig) or better to enable readings tobe made to 2.0 kPa (0.25 psig).7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee onAna

25、lytical Reagents of theAmerican Chemical Society.87.2 Purity of WaterUnless otherwise indicated, referencesto reagent water shall be understood to mean distilled watermeeting requirements of reagent water as defined by Type I ofSpecification D 1193.7.3 Acetone,CH3COCH3.7.4 Air, containing 2000 ppm n

26、itrogen dioxide,NO2(commercially available compressed gas mixture, certi-fied within 65 %).7.5 Cyclo-hexane,C6H12, Practical Grade or other suitablehydrocarbon solvent. (WarningHighly flammable. Skin ir-ritant on repeated contact. Aspiration hazard.)7.6 Isopropyl Alcohol,CH3CH(CH3)OH.7.7 Oxygen, 99.

27、8 %.8. Materials8.1 TFOUT Catalyst B Package:78.1.1 Fuel ComponentThe fuel component is a nitratedgasoline fraction or organic equivalent. This component maybe prepared in accordance with the procedures described inAnnex A3.8.1.2 Soluble Metal Catalyst MixtureThis catalyst is amixture of soluble met

28、al catalysts (lead, iron, manganese, andtin). The catalyst may be prepared according to the proceduresdescribed in Annex A4.8.1.2.1 Other oxidation stability test methods have demon-strated that soluble metal catalyst supplies may be inconsistentand have significant effects on the test results. Thus

29、, for testcomparisons, the same source and same batch of metalnaphthenates shall be used.NOTE 2It is good research practice to use the same batches of catalystcomponents when closely comparing engine oils.NOTE 3Slow, steady reactivity of some of the catalyst chemicals canbe a problem. Such problems

30、can be reduced by storing the closed catalystvials in a refrigerator at approximately 5C. The catalyst chemicals remaineffective up to six months after the septum is punctured, if they are storedas noted above.8.1.3 Nitro-paraffnThis compound is made up of a nitri-alkane blend.6The sole source of su

31、pply of the apparatus known to the committee at this timeis Koehler Instrument Co., Inc., 1595 Sycamore Ave., Bohemia, NY11716 andStanhope-Seta, London St., Chertsey, Surrey, KT16 8AP, U.K. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadquarters. Y

32、our comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.7The sole source of supply of the apparatus known to the committee at this timeis Tannas Co., 4800 James Savage Rd., Midland, MI 48642. If you are aware ofalternative suppliers, p

33、lease provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.8Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For sugg

34、estions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards 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 Pressure versus Time D

35、iagram of the Oxidation TestD7098082NOTE 4Suitably prepared catalyst packages may be purchased fromTannas Co.78.2 Varnish and Deposit Remover, water-soluble varnishremover or other engine varnish/deposit removers.8.3 Silicone Stopcock Grease.9. Preparation of Apparatus9.1 Glass Sample ContainerA cle

36、an glass sample con-tainer is important for obtaining repeatable results. Thoroughcleaning can be accomplished by (a) rinsing with cyclo-hexaneor other suitable hydrocarbon solvent, (b) soaking in concen-trated solution of a water-soluble varnish remover, (c) thor-oughly rinsing with water, (d) rins

37、ing with acetone, (e) andpermitting to dry.NOTE 5A segmented glass reaction dish has been found suitable toprevent premature mixing of the catalyst components (see Fig. A2.4)9.2 Cleaning of Pressure VesselFill with concentratedsolution of a water-soluble varnish remover and soak forsuitable time, ri

38、nse with water, rinse with acetone, and permitto dry.9.3 Cleaning of Pressure Vessel StemPeriodically disas-semble, inspect, and clean the pressure vessel stem. Rinse theinside of the stem with isopropyl alcohol and blow dry with oilfree compressed air. For users of apparatus described in AnnexA1, p

39、eriodically insert a dry pipe cleaner into the transducerline opening for removal of potential residue buildup.NOTE 6Replace O-rings when reassembling the pressure transducers.9.4 Periodically pressure test the pressure vessels at 690 kPa(100 psi) with air or oxygen. If the pressure drops more than0

40、.690 kPa (0.1 psi) on the pressure gauge within 60 s, replacethe O-ring seals and inspect the valve seals according tomanufacturers directions. If the problem continues, contact thespecific equipment manufacturer.NOTE 7Previous versions of this test method have called for hydro-static testing of the

41、 pressure vessel. This was found unnecessary at therelatively low pressures involved in running this test method.9.5 Cleaning of Catalyst SyringesUse individual catalystsyringes for each catalyst component. Thoroughly clean anddry syringes prior to each use. (See Annex A5 for recom-mended procedure.

42、)10. Procedure10.1 Weighing and Mixing Sample and Catalyst Compo-nents:10.1.1 Place the clean glass sample container onto theprecision balance and tare.10.1.2 Weigh 1.500 6 0.001 g of oil sample into thecontainer and tare.10.1.3 Add 0.045 6 0.001 g of the soluble metal catalystmixture into the glass

43、 sample container and tare.10.1.4 Add 0.030 6 0.001 g each of the fuel component,nitro-paraffin and reagent water to the glass sample containerand tare each time. It is easiest to add the distilled water lastand place on top of the oil sample.10.1.5 Just prior to inserting the glass sample container

44、 intothe pressure vessel, thoroughly mix the catalyst componentswithin the sample container by hand-rotation (approximatelyfive rotations) and proceed immediately to 10.2. Delay mayresult in variation of results.10.2 Pressure Vessel Assembly and ChargingImmediatelyand rapidly assemble and charge the

45、 pressure vessel in accor-dance with apparatus type (see A1.2 or A2.7).NOTE 8Avoid releasing the oxygen too rapidly by decreasing thepressure to atmospheric in no less than 1 min to avoid possible foamingand overflow of the sample from the glass sample container.10.3 OxidationBefore starting the tes

46、t, bring the heatingbath to the test temperature at 160C and insert the pressurevessel(s) in accordance with apparatus type (seeA1.3 orA2.8).10.3.1 Allow the bath temperature to level out at the testtemperature, which must occur within 15 min after insertion ofthe pressure vessel. Maintaining the te

47、st temperature within thespecified limits of 160 6 0.3C during the entire test run is themost important single factor ensuring both repeatability andreproducibility of test results. If the test temperature cannot bemaintained as specified, the test results shall not be consideredvalid.NOTE 9The time

48、 for the bath to reach the operating temperature afterinsertion of the pressure vessel may differ for different apparatus assem-blies and shall be observed for each unit (a unit may carry one, two, three,or four pressure vessels). The objective is to find a set of conditions, whichdoes not permit a

49、drop of more than 2C after insertion of the pressurevessel(s) and allows the pressure vessel pressure to reach plateau within15 min.10.4 Keep the pressure vessel completely submerged andmaintain continuous and uniform rotation throughout the test.A standard rotational speed of 100 6 5 r/min is required; anyvariation in this speed could cause erratic results.10.5 Monitor the pressure of the pressure vessel preferablyusing a strip chart or some other form of electronic datacollection program. If a dial pressure gauge is used, makereadings at lea