1、Designation: D4742 16D4742 17Standard Test Method forOxidation Stability of Gasoline Automotive Engine Oils byThin-Film Oxygen Uptake (TFOUT)1This standard is issued under the fixed designation D4742; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、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 of engine oils for gasoline automoti
3、ve engines. This test, run at 160 C,utilizes a high pressure reactor pressurized with oxygen along with a metal catalyst package, a fuel catalyst, and water in a partialsimulation of the conditions to which an oil may be subjected in a gasoline combustion engine. This test method can be used forengi
4、ne oils with viscosity in the range from 4 mm2/s (cSt) to 21 mm2/s (cSt) at 100 C, including re-refined oils.1.2 This test method is not a substitute for the engine testing of an engine oil in established engine tests, such as Sequence IIID.1.3 The values stated in SI units are to be regarded as sta
5、ndard. No other units of measurement are included in this standard.1.3.1 ExceptionPressure units are provided in psig, and dimensions are provided in inches in Annex A1, because these arethe industry accepted standard and the apparatus is built according to the figures shown.1.4 This standard does n
6、ot purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific warning statements, see Sec
7、tions 7 and 8.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical
8、Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A314 Specification for Stainless Steel Billets and Bars for ForgingB211 Specification for Aluminum and Aluminum-Alloy Rolled or Cold Finished Bar, Rod, and WireD664 Test Method for Acid Number of Petroleum Products by Poten
9、tiometric TitrationD1193 Specification for Reagent WaterD2272 Test Method for Oxidation Stability of Steam Turbine Oils by Rotating Pressure VesselD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsE1 Specification for ASTM Liquid-in-Glass Thermometers3. Terminology3.1 Definitions
10、 of Terms Specific to This Standard:3.1.1 break pointthe precise point of time at which rapid oxidation of the oil begins.3.1.2 oxidation induction timethe time until the oil begins to oxidize at a relatively rapid rate as indicated by the decrease ofoxygen pressure.3.1.3 oxygen uptakeoxygen absorbe
11、d by oil as a result of oil oxidation.4. Summary of Test Method4.1 The test oil is mixed in a glass container with three other liquids that are used to simulate engine conditions: (1) anoxidized/nitrated fuel component (Annex A2), (2) a mixture of soluble metal naphthenates (lead, copper, iron, mang
12、anese, and tinnaphthenates (Annex A3), and (3) Type I reagent water.1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.09.0G on Oxidation Testing of Engine Oils.Current edition appr
13、oved June 1, 2016July 1, 2017. Published June 2016July 2017. Originally approved in 1988. Last previous edition approved in 20082016 asD4742 08D4742 16.1. DOI: 10.1520/D4742-16.10.1520/D4742-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at se
14、rviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version
15、. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section
16、 appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 The glass container holding the oil mixture is placed in a high pressure reactor equipped with a pressure gauge. The highpressure reactor is seale
17、d, charged with oxygen to a pressure of 620 kPa (90 psig), and placed in an oil or dry bath3,4 at 160 Cat an angle of 30 from the horizontal. The high pressure reactor is rotated axially at a speed of 100 rmin forming a thin film ofoil within the glass container resulting in a relatively large oil-o
18、xygen contact area.NOTE 1A pressure sensing device can be used in place of a pressure gauge.4.3 The pressure of the high pressure reactor is recorded continuously from the beginning of the test and the test is terminatedwhen a rapid decrease of the high pressure reactor pressure is observed (Point B
19、, Fig. A1.2). The period of time that elapsesbetween the time when the high pressure reactor is placed in the oil or dry bath and the time at which the pressure begins todecrease rapidly is called the oxidation induction time and is used as a measure of the relative oil oxidation stability.5. Signif
20、icance and Use5.1 This test method is used to evaluate oxidation stability of lubricating base oils with additives in the presence of chemistriessimilar to those found in gasoline engine service. Test results on some ASTM reference oils have been found to correlate withsequence IIID engine test resu
21、lts in hours for a 375 % viscosity increase.5 The test does not constitute a substitute for enginetesting, which measures wear, oxidation stability, volatility, and deposit control characteristics of lubricants. Properly interpreted,the test may provide input on the oxidation stability of lubricants
22、 under simulated engine chemistry.5.2 This test method is intended to be used as a bench screening test and quality control tool for lubricating base oilmanufacturing, especially for re-refined lubricating base oils. This test method is useful for quality control of oxidation stabilityof re-refined
23、oils from batch to batch.3 The sole source of supply of the catalyst and dry bath known to the committee at this time is Tannas Co., 4800 James Savage Rd., Midland, MI 48642.4 If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments
24、 will receive careful consideration at ameeting of the responsible technical committee,1 which you may attend.5 Ku, C. S. and Hsu, S. M., “A Thin Film Uptake Test for the Evaluation of Automotive Lubricants,” Lubrication Engineering , 40, 2, 1984, pp. 7583.FIG. 1 Schematic Drawing of Oxidation Test
25、ApparatusD4742 1725.3 This test method is useful for screening formulated oils prior to engine tests. Within similar additive chemistry and base oiltypes, the ranking of oils in this test appears to be predictive of ranking in engine tests. When oils having completely differentadditive chemistry or
26、base oil type are compared, oxidation stability results may not reflect the actual engine test result.5.4 Other oxidation stability test methods have demonstrated that soluble metal catalyst supplies are very inconsistent and theyhave significant effects on the test results. Thus, for test compariso
27、ns, the same source and same batch of metal naphthenates shallbe used.NOTE 2It is also recommended as a good research practice not to use different batches of the fuel component in test comparisons.6. Apparatus6.1 High Pressure Reactor, glass sample container, aluminum insert, pressure gauge, thermo
28、meter, test bath and accessories areshown in Fig. 2 and Fig. 3, and described in Annex A1.FIG. 2 Pressure versus Time Diagram of the Oxidation TestD4742 173NOTE 3It is reported in literature5 that the oxidation high pressure reactor can be modified from the Test Method D2272 oxidation high pressurer
29、eactor by insertion of an aluminum cylinder.6.2 Precision Pressure GaugeA certified precision pressure gauge is used to accurately control the oxygen feed to the highpressure reactor. The gauge has a sufficient range to encompass 0 kPa to 650 kPa or more (;90 psig) required by the test methodwith di
30、vision 2.0 kPa (;0.5 psig) or better to enable readings to be made to 2.0 kPa (;0.25 psig).7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytic
31、al Reagents of the American Chemical Society.67.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean distilled water meetingrequirements of reagent water as defined by Type I of Specification D1193.7.3 Acetone, CH3COCH3. (WarningExtremely flammable. Irritating
32、 to skin, eyes, and mucous membranes.)7.4 Air, containing 2000 ppm nitrogen dioxide, NO2 (commercially available compressed gas mixture, certified within 65 %).(WarningNitrogen dioxide is poisonous.)7.5 Hexane, C6H14, Practical Grade or other suitable hydrocarbon solvent. (WarningExtremely flammable
33、. Harmful ifinhaled. May produce nerve cell damage. Skin irritant on repeated contact. Aspiration hazard.)6 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Society, s
34、ee Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.FIG. 3 Schematic Drawing of an Assembled Vessel, Aluminum Insert, and Glass Sample ContainerD4742 1747.6 Is
35、opropyl Alcohol, CH3CH(CH3)OH. (WarningFlammable. Eye irritant. Vapors narcotic.)7.7 Oxygen. (WarningOxygen vigorously accelerates combustion.)7.8 Potassium Hydroxide, Alcohol Solution (1.5 %)Dissolve 12 g of potassium hydroxide (KOH) pellets in 1 L of 99 %isopropyl alcohol. (WarningPotassium hydrox
36、ide is corrosive.)8. Materials8.1 Fuel ComponentThe fuel component is an oxidized nitrated gasoline fraction. This component may be prepared inaccordance with the procedures described in Annex A2. (See 8.2 and Note 4.) (WarningFuel component is extremelyflammable. Vapors harmful if inhaled. Skin irr
37、itant on repeated contact. Aspiration hazard.)8.2 Soluble Metal Catalyst MixtureThis catalyst3,4 is a mixture of soluble metal catalysts (lead, copper, iron, manganese, andtin). The catalyst may be prepared according to the procedures described in Annex A3. (See 8.2 and Note 4.) (WarningLeadand mang
38、anese naphthenates are known to be poisonous, but all naphthenates should be handled with care. Naphthenates are alsoflammable.)NOTE 4With some catalyst chemicals, reactivity can be a problem. This can be curtailed by storing in a refrigerator at approximately 5 C. Thecatalyst chemicals remain effec
39、tive up to six months after the septum is punctured if they are stored as noted above.NOTE 5It is recommended that each new batch of fuel or metal catalyst be correlated with a standard reference oil, in accordance with good laboratorypractices.8.3 Liquid Detergent (Industrial Strength).8.4 Silicone
40、 Stopcock Grease.9. Preparation of Apparatus9.1 Glass Sample ContainerRinse the glass sample container with hexane or other suitable hydrocarbon solvent. Clean theglass container with hot detergent solution and water. Rinse the container with acetone. Blow the container dry with cleancompressed air.
41、NOTE 6A clean glass sample container is important for obtaining repeatable results. Thorough cleaning of the glass sample can be accomplished by(1) hexane rinse, (2) acetone soak for 15 min, (3) hot detergent solution and water soak for 4 h, (4) acetone rinse, and (5) hexane rinse. A clean glasssamp
42、le container is important for obtaining repeatable results.NOTE 7A segmented glass sample container has been found suitable to prevent premature mixing of the catalyst components.9.2 Cleaning of High Pressure ReactorWash the inside of the high pressure reactor, aluminum insert, lid, and inside with
43、hotdetergent solution and water. Rinse the inside of the stem with isopropyl alcohol and blow dry with clean compressed air. If thehigh pressure reactor, insert, lid, or inside of the stem emits acidic odor after simple cleaning, wash with a solution of alcoholicpotassium hydroxide (KOH) of 1.5 %, a
44、nd repeat the cleaning procedures. For dry baths, refer to manufacturers manuals fordetails.9.3 Cleaning of High Pressure Reactor StemIt is recommended to periodically disassemble, inspect, and clean the highpressure reactor stem. Rinse the inside of the stem with isopropyl alcohol and blow dry with
45、 clean compressed air.After cleansing,it is recommended to insert a dry pipe cleaner into the transducer line opening for removal of potential residue buildup.NOTE 8It is recommended to replace the O-rings when reassembling the pressure transducers.9.4 To obtain a representative sample of stocks of
46、uniform petroleum products, follow Practice D4057.9.5 Cleaning of Catalyst SyringesIndividual catalyst syringes are to be used for each catalyst component. They are to bethoroughly cleaned and dried prior to each use. (See Annex A4 for recommended procedure.)10. Procedure10.1 Weighing and Mixing Sam
47、ple and Catalyst Components:10.1.1 Weigh the clean glass sample container to the nearest mg.10.1.2 Weigh 1.500 g 6 0.001 g of oil sample into the container.10.1.3 Add 0.060 g 6 0.001 g each of both the fuel component and the soluble metal catalyst mixture.10.1.4 Add 0.030 g 6 0.001 g of distilled wa
48、ter (Type I) to the glass sample container.10.1.5 Just prior to inserting the glass sample container into the high pressure reactor, thoroughly mix the catalyst componentswithin the sample container by hand-rotation (approximately five rotations) and proceed immediately to 10.2. Delay may resultin v
49、ariation of results.10.2 High Pressure Reactor Charging and AssemblyImmediately and rapidly assemble the high pressure reactor as shown inFig. 1 and Fig. 2. Refer to manufacturers manual for details.10.2.1 Put the aluminum insert into the high pressure reactor 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 the TFE disk and the glass sample container.D4742 175NOTE 9The stainless steel hold-down spring not only holds down the TFE cover
