1、Designation: D 942 02 (Reapproved 2007)Designation: 142/85 (92)An American National StandardStandard Test Method forOxidation Stability of Lubricating Greases by the OxygenPressure Vessel Method1This standard is issued under the fixed designation D 942; the number immediately following the designati
2、on 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 (e) indicates an editorial change since the last revision or reapproval.This test method has been approved by the spon
3、soring committee and accepted by the cooperating societies in accordance with theestablished procedures.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method determines resistance of lubricatinggreases to oxidation when stored statically in an
4、 oxygenatmosphere in a sealed system at an elevated temperature underconditions of test.1.2 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
5、 and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements see Sections 6 and 7.2. Referenced Documents2.1 ASTM Standards:A 240/A 240M Specification for Chromium andChromium-Nickel Stainless Steel Plate, Sheet, and Stripfor Pressure Vessels and for Genera
6、l ApplicationsD 525 Test Method for Oxidation Stability of Gasoline(Induction Period Method)E1 Specification for ASTM Liquid-in-Glass Thermometers2.2 Other Standards:IP Specification for Standard IP Thermometers2BS 970:1983 Part I, Section S33. Summary of Test Method3.1 The sample of grease is oxidi
7、zed in a pressure vesselheated to 99C (210F) and filled with oxygen at 110 psi (758kPa). Pressure is observed and recorded at stated intervals. Thedegree of oxidation after a given period of time is determinedby the corresponding decrease in oxygen pressure.NOTE 1The pressure vessel has been referre
8、d to as “a bomb” inprevious issues of this test method.NOTE 2The accepted unit of pressure is the pascal (Pa) for ASTMmethods and will be parenthetically included after the conventionalpound-force per square inch (psi) value. The Institute of Petroleum usesthe bar as a pressure measurement. Conversi
9、on of units may be obtainedas follows:To convert from pound-force per square inch (psi) to pascal (Pa)multiply by 6.894757 3 103.To convert from pound-force per square inch (psi) to bar multiply by0.06894757.To convert from bar to pascal (Pa) multiply by 105.4. Significance and Use4.1 This test meth
10、od measures the net change in pressureresulting from consumption of oxygen by oxidation and gain inpressure due to formation of volatile oxidation by-products.This test method may be used for quality control to indicatebatch-to-batch uniformity. It predicts neither the stability ofgreases under dyna
11、mic service conditions, nor the stability ofgreases stored in containers for long periods, nor the stabilityof films of greases on bearings and motor-parts. It should notbe used to estimate the relative oxidation resistance of differentgrease types.5. Apparatus5.1 Oxidation Pressure Vessel, Sample D
12、ish, Dish Holder,Pressure Gage and Oil Bath as described in detail in theAnnex.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.09.0E on Oxidation of Greases.In the IP, this test method is under
13、the jurisdiction of the StandardizationCommittee.Current edition approved May 1, 2007. Published June 2007. Originallyapproved in 1947. Last previous edition approved in 2002 as D 942 02.2Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.uk.3Availa
14、ble from British Standards Institute (BSI), 389 Chiswick High Rd.,London W4 4AL, U.K., http:/www.bsi-.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.NOTE 3Other const
15、ant-temperature baths may be used if they areequivalent in heat capacity and thermal gradient characteristics to the oilbath described in the Annex and can be shown to maintain the pressurevessel at the prescribed test temperature.5.2 Thermometer, having a range as shown below andconforming to the r
16、equirements as prescribed in SpecificationE1or in the Specifications for IP Standard Thermometers:Thermometer NumberTemperature Range ASTM IP95 to 103C 22C 24C204 to 218F 22F 24F6. Material6.1 Oxygen, of not less than 99.5 % purity.6.2 (WarningSince oxygen vigorously accelerates com-bustion, observe
17、 the following procedures: (1) Keep oil andgrease away from oxygen at high pressure. Keep oil and greaseaway from all regulators, gages and control equipment. (2) Useoxygen only with equipment conditioned for oxygen service bycareful cleaning to remove oil and grease from area in contactwith high pr
18、essure 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 before openingoxygen cylinder.
19、 (6) All equipment used must be suitable andrecommended for oxygen service. (7) Never attempt to transferoxygen from cylinder in which it is received to any othercylinder prior to use. (8) Do not drop oxygen cylinders. (9)Keep cylinder valve closed when not in use. (10) Stand awayfrom valve when ope
20、ning cylinder. (11) Do not breathe or usetechnical grade oxygen for inhalation purposes. (12) SeeCompressed Gas Association Booklets G-4 and G-4-14fordetails of safe practice in the use of oxygen.)6.3 n-Heptane(WarningFlammable. Harmful if in-haled. Keep away from heat, sparks, and open flame. Keepc
21、ontainer closed. Use with adequate ventilation. Avoid breath-ing vapor or spray mist. Avoid prolonged or repeated contactwith skin.)6.4 Cleaning Solution, capable of satisfactorily cleaning theglassware used in the test. The criterion for satisfactorycleaning shall be a matching of the quality of th
22、at obtained withchromic acid cleaning solutions (fresh chromic acid, 6-hsoaking period, rinsing with distilled water and drying) orsome other equivalently strong oxidizing non-chromium con-taining acid cleaning solutions on used sample dishes.(WarningCauses severe burns. A recognized carcinogen.Stro
23、ng oxidizer; contact with organic material may cause fire.Hygroscopic.) (WarningDo not get in eyes, on skin, or onclothing.Avoid breathing vapor or mist. Keep container closed.Use with adequate ventilation. Do not take internally.) For thiscomparison, visual appearance and mass loss on heating thegl
24、assware under test conditions may be used. Detergent clean-ing avoids the potential hazards and inconveniences related tohandling corrosive chromic acid solutions; this procedureremains the reference cleaning practice and as such mayfunction as an alternate to the preferred procedure, cleaningwith d
25、etergent solutions.7. Preparation of Apparatus7.1 Clean the sample dishes from all contamination fromprevious runs and from dust settling from the air by washingthem with n-heptane and then with a cleaning solution. Followthe final cleaning operation by a thorough tap water rinse, adistilled water r
26、inse, and drying in an oven. Handle the cleandishes only with forceps. (WarningHandle in well-ventilated area, preferably in a hood. Keep away from heat,sparks, and open flame. Keep container closed when not inuse.) (WarningSee 6.3, and avoid skin contact, which maycause severe burns.)7.2 If lacquer
27、 is found after a run, clean the inside of theoxidation pressure vessel and the metal supports for thepressure vessel dishes by immersing in an appropriate solventcapable of removing the lacquer, such as gum solvent asspecified in Test Method D 525, and scrubbing with a bristlebrush followed by dryi
28、ng. Scrub further with water and a finescouring powder until all the lacquer deposits are removed.Follow the scouring operation by a thorough tap water rinse, adistilled water rinse, and drying in an oven. Handle the cleanmetal supports only with forceps.8. Procedure8.1 Fill each of the five dishes
29、with 4.00 6 0.01 g of grease.Distribute the samples in the dishes in a uniform layer with asmooth level upper surface. Place the filled dishes on the fivebottom shelves of the holder, leaving the top shelf to act as acover to prevent condensing volatile products from droppinginto the grease samples.
30、 When assembling the pressure vessel,place a small ball of glass wool in the bottom of the stem.8.2 Place the dish holder in the pressure vessel with asealing gasket in place, and close the pressure vessel bytightening the bolts slowly and uniformly. Clear the air fromthe pressure vessel by introduc
31、ing oxygen slowly until apressure of 100 psi (689 kPa) is attained, then allow the oxygento escape slowly; repeat four times. Bring the oxygen pressureto a value as shown in the following table:Room Temperature PressureC F psi kPa17 to 20 62 to 68 85 58620 to 23 68 to 74 86 59323 to 27 74 to 80 87 6
32、0027 to 30 80 to 86 88 60730 to 33 86 to 92 89 61433 to 37 92 to 98 90 62137 to 40 98 to 104 91 627Allow the pressure vessel to stand overnight to make surethere are no leaks.NOTE 4It has been found that pressure readings as shown above willresult in a pressure reading of 110 6 2 psi (758 6 14 kPa)
33、when thepressure vessel is placed in the bath in the following step, 8.3, andconsequently no release of oxygen will be required in most cases. Thisminimizes the chance of a leak developing at the valve after the overnightcheck for leaks has shown the pressure vessel to be satisfactory.8.3 Place the
34、pressure vessel in the oil bath maintained at atemperature of 99 6 0.5C (210 6 1.0F). As the pressurerises, if needed, intermittently release oxygen from the pressure4Available from Compressed Gas Association (CGA), 4221 Walney Rd., 5thFloor, Chantilly, VA 20151-2923, http:/.D 942 02 (2007)2vessel u
35、ntil a constant pressure of 110 6 2 psi (758 6 14 kPa)is obtained and maintained for at least 2 h. A gradual drop inpressure indicates a continuous leak in the pressure vessel.Observe and record the pressure at least every 24 h. In case aleak develops, do not report the results but repeat the test.8
36、.4 Start timing at the moment of immersion of the pressurevessel in the oil bath, and continue the oxidation for the timeperiod specified.NOTE 5Specifications are usually given in terms of pressure drop inpounds per square inch, or kilopascals at one or more time intervals, forinstance, after 100, 2
37、00 h, and so forth.9. Report9.1 Report the average of duplicate determinations as pres-sure drop in pounds per square inch, or kilopascals for thespecified test time, or times in hours, according to Test MethodD 942.10. Precision and Bias10.1 The precision of this test method as determined bystatist
38、ical examination of interlaboratory results is as follows:10.1.1 RepeatabilityThe difference between two test re-sults, obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialwould, in the long run, in the normal and correct operation ofthe
39、 test method, exceed the following values only in one casein twenty:Mean Pressure Drop, psi (kPa) Repeatability0 to 5 (34.5) 2 (13.8)Over 5 to 10 (34.5 to 68.9) 3 (20.7)Over 10 to 20 (68.9 to 138) 6 (41.4)Over 20 to 55 (138 to 379) 10 (68.9)10.1.2 ReproducibilityThe difference between two singleand
40、independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of the testmethod, exceed the following values only in one case intwenty:Mean Pressure Drop, psi (kPa) Reproducibility0 to 5 (3
41、4.5) 3 (20.7)Over 5 to 10 (34.5 to 68.9) 5 (34.5)Over 10 to 20 (68.9 to 138) 8 (55.2)Over 20 to 55 (138 to 379) 20 (138)NOTE 6These precision values apply only to that portion of the datafor which oxygen is absorbed at a rate approximately proportional to time(for example, the induction period). The
42、 end of the induction period isevidenced by a rapid acceleration in the rate of oxygen absorption in ashort time interval.10.2 The following information on the precision of this testmethod has been developed by the Institute of Petroleum(London). The precision of this test method as determined bysta
43、tistical examination of interlaboratory results is as follows:10.2.1 RepeatabilityThe difference between two test re-sults, obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialwould, in the long run, in the normal and correct operation o
44、fthe test method, exceed the following values only in one casein twenty:Mean PressureDrop, psigRepeatabilityMean PressureDrop, kPaRepeatability0to2 1 0 53to6 2 5to20 107 to 10 3 25 to 40 1511to14 4 45to60 2015 to 18 5 65 to 85 2519 to 20 6 90 to 105 30110 to 125 35130 to 140 4010.2.2 Reproducibility
45、The difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of the testmethod, exceed the following values only in one case intwenty:Mean PressureDrop
46、, psigReproduci-bilityMean PressureDrop, kPaReproduci-bility0to3 2 0 104to6 3 5to20 157to9 4 25to35 2010 to 12 5 40 to 50 2513 to 15 6 55 to 65 3016 to 17 7 70 to 80 3518 to 20 8 85 to 95 40100 to 110 45115 to 125 50130 to 135 55140 60These precision values have been obtained by statisticalexaminati
47、on of interlaboratory test results,5and were firstpublished in 1965.10.3 BiasThe procedure in this test method has no biasbecause the value of oxidation stability can be defined only interms of a test method.11. Keywords11.1 grease; oxidation5See IP Standards for Petroleum and Its Products, Part 1,
48、Appendix E.D 942 02 (2007)3ANNEX(Mandatory Information)A1. APPARATUSA1.1 Oxidation Pressure Vessel, of the type and conformingto the dimensions shown in Fig. A1.1, shall be made of 18 %chromium, 8 % nickel alloy steel. A suitable material is analloy steel conforming to Grade S, Type 304, of Specific
49、ationsA 240 or BS 970: 1983 Part 1, Section S (steel 302S31 or321S31). The pressure vessel shall be capable of withstandingwith safety a working pressure of 180 psi (1241 kPa) at 99C(210F) and provided with a lead or TFE-fluorocarbon gasketfor sealing. To facilitate cleaning, give a high polish to theinterior surfaces of the pressure vessel, the lid, and the insideof the pipe carrying the pressure gage. The pressure vessel shallbe so constructed that its volume without the dish holder anddishes is 185 6 6 mL, measured to the leve
