1、Designation: D 4742 08An American National StandardStandard Test Method forOxidation Stability of Gasoline Automotive Engine Oils byThin-Film Oxygen Uptake (TFOUT)1This standard is issued under the fixed designation D 4742; the number immediately following the designation indicates the year oforigin
2、al 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 test method evaluates the oxidation stability ofengine oils
3、 for gasoline automotive engines. This test, run at160C, utilizes a high pressure reactor pressurized with oxygenalong with a metal catalyst package, a fuel catalyst, and waterin a partial simulation of the conditions to which an oil may besubjected in a gasoline combustion engine. This test methodc
4、an be used for engine oils with viscosity in the range from 4mm2/s (cSt) to 21 mm2/s (cSt) at 100C, including re-refinedoils.1.2 This test method is not a substitute for the engine testingof an engine oil in established engine tests, such as SequenceIIID.1.3 The values stated in SI units are to be r
5、egarded as thestandard. The values given in parentheses are provided forinformation purposes only.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
6、 practices and determine the applica-bility of regulatory limitations prior to use. For specificwarning statements, see Sections 7 and 8.2. Referenced Documents2.1 ASTM Standards:2A 314 Specification for Stainless Steel Billets and Bars forForgingB211 Specification for Aluminum and Aluminum-AlloyBar
7、, Rod, and WireD 664 Test Method forAcid Number of Petroleum Productsby Potentiometric TitrationD 1193 Specification for Reagent WaterD 2272 Test Method for Oxidation Stability of Steam Tur-bine Oils by Rotating Pressure VesselD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsE1
8、Specification for ASTM Liquid-in-Glass Thermometers3. 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
9、 indicated 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 three otherliquids that are used to simulate engine conditions: (1)anoxidized/nitrated fuel component (Annex
10、 A2), (2) a mixture ofsoluble metal naphthenates (lead, copper, iron, manganese, andtin naphthenates (Annex A3), and (3) Type II reagent water.4.2 The glass container holding the oil mixture is placed ina high pressure reactor equipped with a pressure gauge. Thehigh pressure reactor is sealed, charg
11、ed with oxygen to apressure of 620 kPa (90 psig), and placed in an oil bath at160C at an angle of 30 from the horizontal. The high pressurereactor is rotated axially at a speed of 100 r/min forming a thinfilm of oil within the glass container resulting in a relativelylarge oil-oxygen contact area.NO
12、TE 1A pressure sensing device can be used in place of a pressuregauge.4.3 The pressure of the high pressure reactor is recordedcontinuously from the beginning of the test and the test isterminated when a rapid decrease of the high pressure reactor1This test method is under the jurisdiction of ASTM C
13、ommittee 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. Originallyapproved in 1988. Last previous edition approved in 2002 as D 474202a.2For referen
14、ced 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.1*A Summary of Changes section appears at the end of this standard.Copyri
15、ght ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.pressure is observed (Point B, Fig. A1.2). The period of timethat elapses between the time when the high pressure reactor isplaced in the oil bath and the time at which the pressure beginsto d
16、ecrease rapidly is called the oxidation induction time and isused as a measure of the relative oil oxidation stability.5. Significance and Use5.1 This test method is used to evaluate oxidation stabilityof lubricating base oils with additives in the presence ofchemistries similar to those found in ga
17、soline engine service.Test results on some ASTM reference oils have been found tocorrelate with sequence IIID engine test results in hours for a375 % viscosity increase.3The test does not constitute asubstitute for engine testing, which measures wear, oxidationstability, volatility, and deposit cont
18、rol characteristics of lubri-cants. Properly interpreted, the test may provide input on theoxidation stability of lubricants under simulated engine chem-istry.5.2 This test method is intended to be used as a benchscreening test and quality control tool for lubricating base oilmanufacturing, especial
19、ly for re-refined lubricating base oils.This test method is useful for quality control of oxidationstability of re-refined oils from batch to batch.5.3 This test method is useful for screening formulated oilsprior to engine tests. Within similar additive chemistry andbase oil types, the ranking of o
20、ils in this test appears to bepredictive of ranking in engine tests. When oils havingcompletely different additive chemistry or base oil type arecompared, oxidation stability results may not reflect the actualengine test result.5.4 Other oxidation stability test methods have demon-strated that solub
21、le metal catalyst supplies are very inconsistentand they have significant effects on the test results. Thus, fortest comparisons, the same source and same batch of metalnaphthenates shall be used.NOTE 2It is also recommended as a good research practice not to usedifferent batches of the fuel compone
22、nt in test comparisons.6. Apparatus6.1 High Pressure Reactor, glass sample container, alumi-num insert, pressure gauge, thermometer, test bath and acces-sories are shown in Fig. 1 and Fig. 2 and described in AnnexA1.NOTE 3It is reported in literature3that the oxidation high pressurereactor can be mo
23、dified from the Test Method D 2272 oxidation highpressure reactor by insertion of an aluminum cylinder.6.2 Precision Pressure GaugeA certified precision pres-sure gauge is used to accurately control the oxygen feed to thehigh pressure reactor. The gauge has a sufficient range to3Ku, C. S. and Hsu, S
24、. M., “A Thin Film Uptake Test for the Evaluation ofAutomotive Lubricants,” Lubrication Engineering , 40, 2, 1984, pp. 7583.FIG. 1 Schematic Drawing of Oxidation Test ApparatusD4742082encompass 0 to 650 kPa or more (; 90 psig) required by thetest method with division 2.0 kPa (; 0.5 psig) or better t
25、oenable readings to be 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 onAnalytical Reagents of theAmerican Chemical Soc
26、iety.47.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean distilled water meetingrequirements of reagent water as defined by Type I of Speci-fication D 1193.7.3 Acetone,CH3COCH3.(WarningExtremely flam-mable. Irritating to skin, eyes, and mucous membranes.)7.
27、4 Air, containing 2000 ppm nitrogen dioxide, NO2(com-mercially available compressed gas mixture, certified within65 %). (WarningNitrogen dioxide is poisonous.)7.5 Hexane,C6H14, Practical Grade or other suitable hydro-carbon solvent. (WarningExtremely flammable. Harmful ifinhaled. May produce nerve c
28、ell damage. Skin irritant onrepeated contact. Aspiration hazard.)7.6 Isopropyl Alcohol,CH3CH(CH3)OH. (WarningFlammable. Eye irritant. Vapors narcotic.)7.7 Oxygen.(WarningOxygen vigorously acceleratescombustion.)7.8 Potassium Hydroxide, Alcohol Solution (1.5 %)Dissolve 12 g of potassium hydroxide (KO
29、H) pellets in 1 L of99 % isopropyl alcohol. (WarningPotassium hydroxide iscorrosive.)8. Materials8.1 Fuel ComponentThe fuel component is an oxidizednitrated gasoline fraction. This component may be prepared inaccordance with the procedures described in Annex A2. (See8.2 and Note 4.) (WarningFuel com
30、ponent is extremelyflammable. Vapors harmful if inhaled. Skin irritant on repeatedcontact. Aspiration hazard.)8.2 Soluble Metal Catalyst MixtureThis catalyst5,6is amixture of soluble metal catalysts (lead, copper, iron, manga-nese, and tin). The catalyst may be prepared according to theprocedures de
31、scribed in Annex A3. (See 8.2 and Note 4.)(WarningLead and manganese naphthenates are known tobe poisonous, but all naphthenates should be handled with care.Naphthenates are also flammable.)NOTE 4With some catalyst chemicals, reactivity can be a problem.This can be curtailed by storing in a refriger
32、ator at approximately 5C. Thecatalyst chemicals remain effective up to six months after the septum ispunctured if they are stored as noted above.NOTE 5It is recommended that each new batch of fuel or metalcatalyst be correlated with a standard reference oil, in accordance withgood laboratory practic
33、es.8.3 Liquid Detergent (Industrial Strength).8.4 Silicone Stopcock Grease.9. Preparation of Apparatus9.1 Glass Sample ContainerRinse the glass sample con-tainer with hexane or other suitable hydrocarbon solvent. Cleanthe glass container with hot detergent solution and water. Rinsethe container with
34、 acetone. Blow the container dry with cleancompressed air.NOTE 6A clean glass sample container is important for obtainingrepeatable results. Thorough cleaning of the glass sample can be accom-plished by (1) hexane rinse, (2) acetone soak for 15 min, (3) hot detergentsolution and water soak for 4 h,
35、(4) acetone rinse, and (5) hexane rinse. Aclean glass sample container is important for obtaining repeatable results.NOTE 7A segmented glass sample container has been found suitableto prevent premature mixing of the catalyst components.4Reagent Chemicals, American Chemical Society Specifications , A
36、mericanChemical Society, Washington, DC. For suggestions 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. (
37、USPC), Rockville,MD.5The sole source of supply of the catalyst known to the committee at this timeis Tannas Co., 4800 James Savage Rd., Midland, MI 48642.6If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful
38、consider-ation at a meeting of the responsible technical committee,1which you may attend.FIG. 2 Schematic Drawing of an Assembled Bomb, AluminumInsert, and Glass Sample ContainerD47420839.2 Cleaning of High Pressure ReactorWash the inside ofthe high pressure reactor, aluminum insert, lid, and inside
39、 withhot detergent solution and water. Rinse the inside of the stemwith isopropyl alcohol and blow dry with clean compressed air.If the high pressure reactor, insert, lid, or inside of the stememits acidic odor after simple cleaning, wash with 1.5 %alcoholic potassium hydroxide (KOH) solution, and r
40、epeat thecleaning procedures.9.3 Cleaning of High Pressure Reactor StemIt is recom-mended to periodically disassemble, inspect, and clean the highpressure reactor stem. Rinse the inside of the stem withisopropyl alcohol and blow dry with clean compressed air.After cleansing, it is recommended to ins
41、ert a dry pipe cleanerinto the transducer line opening for removal of potentialresidue buildup.NOTE 8It is recommended to replace the O-rings when reassemblingthe pressure transducers.9.4 To obtain a representative sample of stocks of uniformpetroleum products, follow Practice D 4057.9.5 Cleaning of
42、 Catalyst SyringesIndividual catalyst sy-ringes are to be used for each catalyst component. They are tobe thoroughly cleaned and dried prior to each use. (See AnnexA4 for recommended procedure.)10. Procedure10.1 Weighing and Mixing Sample and Catalyst Compo-nents:10.1.1 Weigh the clean glass sample
43、container to the nearestmg.10.1.2 Weigh 1.500 6 0.001 g of oil sample into thecontainer.10.1.3 Add 0.060 6 0.001 g each of both the fuel compo-nent and the soluble metal catalyst mixture.10.1.4 Add 0.030 6 0.001 g of distilled water to the glasssample container.10.1.5 Just prior to inserting the gla
44、ss sample container intothe high pressure reactor, thoroughly mix the catalyst compo-nents within the sample container by hand-rotation (approxi-mately five rotations) and proceed immediately to 10.2. Delaymay result in variation of results.10.2 High Pressure Reactor Charging and AssemblyImmediately
45、 and rapidly assemble the high pressure reactor asshown in Fig. 1.10.2.1 Put the aluminum insert into the high pressurereactor followed by the glass sample container and the TFE(tetra-fluoroethylene) plastic cover disk.10.2.2 Place the stainless hold-down spring on top of theTFE disk and the glass s
46、ample container.NOTE 9The stainless steel hold-down spring not only holds down theTFE cover disk but, more importantly, prevents the glass sample containerfrom slipping inside the high pressure reactor with consequent poorresults.10.2.3 Apply a thin coating of silicone stopcock grease tothe O-ring h
47、igh pressure reactor seal located in the gasketgroove of the high pressure reactor lid to provide lubrication.10.2.4 Insert the lid into the high pressure reactor.10.2.5 Place and tighten the cap on the high pressure reactorto lock down the lid in the high pressure reactor.10.2.6 Attach the high pre
48、ssure oxygen hose and purge thehigh pressure reactor twice at about 620 kPa (90 psig) ofoxygen to remove the air originally present in the high pressurereactor.NOTE 10It is advisable to avoid releasing the oxygen too rapidly bydecreasing the pressure to atmospheric in no less than one minute to avoi
49、dpossible foaming and overflow of the sample from the glass samplecontainer.10.2.7 Charge the high pressure reactor to 620 kPa (90 psig)oxygen at 21C using an in-line precision pressure gauge tomonitor the high pressure reactor pressure with 1 kPa (0.12psig). (For ambient temperatures other than 21C, increase (ordecrease) the initial pressure by 2.5 kPa (0.4 psig) for each 1Cabove (or below) 21C.)10.2.8 Fill the high pressure reactor to the required pressureand close the inlet valve. Test the high pressure reactor forleaks by immersing in wa
