1、Designation: D7873 132Standard Test Method forDetermination of Oxidation Stability and InsolublesFormation of Inhibited Turbine Oils at 120 C Without theInclusion of Water (Dry TOST Method)1This standard is issued under the fixed designation D7873; the number immediately following the designation in
2、dicates 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 () indicates an editorial change since the last revision or reapproval.1NOTESection 3 was corrected editorially in May 2014
3、.2NOTESubsection 13.2 was corrected editorially in August 2015.1. Scope1.1 This test method is used to evaluate the sludgingtendencies of steam and gas turbine lubricants during theoxidation process in the presence of oxygen and metal catalyst(copper and iron) at an elevated temperature. This test m
4、ethodmay be used to evaluate industrial oils (for example, circulat-ing oils and so forth).1.2 This test method is a modification of Test MethodD4310 where the sludging and corrosion tendencies of thesame kinds of oils are determined after 1000 h at 95 C in thepresence of water. Water is omitted in
5、this modification.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3.1 ExceptionThe values in parentheses in some of thefigures are provided for information only for those using oldequipment based on non-SI units.1.4 This s
6、tandard 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 of regulatory limitations prior to use.1.5 WARNINGMercury has be
7、en designated by manyregulatory agencies as a hazardous material that can causecentral nervous system, kidney and liver damage. Mercury, orits vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable
8、 product Ma-terial Safety Data Sheet (MSDS) for details and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfor addi-tional information. Users should be aware that selling mercuryand/or mercury containing products into your state or countrymay be prohibited by law.2. Referenced Documents2.1 ASTM Standar
9、ds:2A510M Specification for General Requirements for WireRods and Coarse Round Wire, Carbon Steel (Metric)(Withdrawn 2011)3B1 Specification for Hard-Drawn Copper WireD943 Test Method for Oxidation Characteristics of InhibitedMineral OilsD1193 Specification for Reagent WaterD2272 Test Method for Oxid
10、ation Stability of Steam Tur-bine Oils by Rotating Pressure VesselD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4310 Test Method for Determination of Sludging andCorrosion Tendencies of Inhibited Mineral OilsE1 Specification for ASTM Liquid-in-Glass ThermometersE230 Specifica
11、tion and Temperature-Electromotive Force(EMF) Tables for Standardized Thermocouples2.2 Other Standards:Specification for IP Standard Thermometers4ISO 3696 Water for Analytical Laboratory UseSpecification and Test Methods53. Terminology3.1 Definitions:1This test method is under the jurisdiction of AS
12、TM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.09.0C on Oxidation of Turbine Oils.Current edition approved Dec. 1, 2013. Published January 2014. DOI: 10.1520/D7873-13E02.2For referenced ASTM standards, visit the ASTM website, w
13、ww.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.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from Energy Institute,
14、61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.5Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Unit
15、ed States13.1.1 sludge, na precipitate or sediment from oxidizedmineral oil that is insoluble in n-heptane.4. Summary of Test Method4.1 Atotal of six to eight tubes containing 360 mLof sampleeach are heated at 120 C with oxygen in the presence of aniron-copper catalyst. Each tube is removed over tim
16、e and thesample is analyzed by Test Method D2272 and the insolublesare measured until the RPVOT residual ratio reaches below25 % or an agreed-upon percentage or specified time. Test runfor a specified time(s) may be run using a single tube or asmany as specified by the requestor. The mass of insolub
17、lematerial of each oil sample is determined gravimetrically byfiltration of a 100 g oil sample through a membrane filter withpore size 1 m. The insoluble mass (mg/kg oil) is plottedagainst RPVOT residual ratio. The insoluble mass in milli-grams per kilogram oil at 25 % or an agreed-upon RPVOTresidua
18、l ratio or specified time is reported.5. Significance and Use5.1 Insoluble material may form in oils that are subjected tooxidizing conditions.5.2 Significant formation of oil insolubles or metal corro-sion products, or both, during this test may indicate that the oilwill form insolubles or corrode
19、metals, or both, resulting invarnish formation during field service. The level of varnishformation in service will be dependent on many factors(turbine design, reservoir temperature, duty-cycle, for example.peaking, cycling, or base-load duty, maintenance, and so forth)and a direct correlation betwe
20、en results in this test and fieldvarnish formation are yet to be established.5.3 Oxidation condition at 120 C under accelerated oxida-tion environment of Test Method D4310 and measurement ofsludge and RPVOT value could reflect a practical oil quality inactual turbine operations. Results from this te
21、st should be usedtogether with other key lubricant performance indicators (in-cluding other established oxidation and corrosion tests) toindicate suitability for service.6. Apparatus6.1 Oxidation Cell, of borosilicate glass, as shown in Fig. 1,consisting of a test tube, condenser, and oxygen deliver
22、y tube.It is recommended to have a test tube with a calibration line at360 mL (maximum error 1 mL). This calibration applies to thetest tube without inserts at 20 C.6.2 Heating Bath, thermostatically controlled, capable ofmaintaining the oil sample in the oxidation cell at a tempera-ture of 120 C 6
23、0.5 C, fitted with a suitable stirring device toprovide a uniform temperature throughout the bath, and largeenough to hold the desired number of oxidation cells immersedin the heating bath to a depth of 355 mm 6 10 mm. Heatedmetal block baths meeting the test method requirements mayalso be used.6.2.
24、1 Studies have suggested that direct sunlight or artificiallight may adversely influence the results of this test. Tominimize effects of light exposure on the lubricant beingtested, light shall be excluded from the lubricant by one ormore of the following ways:6.2.1.1 Use of heated liquid baths that
25、 are designed andconstructed of metal, or combinations of metals and othersuitable opaque materials, that prevent light from entering thetest cell from the sides is preferred. If a viewing window isincluded in the design, this viewing window shall be fitted witha suitable opaque cover and be kept cl
26、osed when no observa-tion is being made.6.2.1.2 If glass heating baths are used, the bath shall bewrapped with aluminum foil or other opaque material.6.2.1.3 Bright light entering the test cell from directlyoverhead can be eliminated by use of an opaque shield.6.3 Flowmeter, with a flow capacity of
27、at least 3 L ofoxygen/hour, and an accuracy of 60.1 L/h.6.4 Heating Bath Thermometer, ASTM Solvents DistillationThermometer having a range from 98 C to 152 C andconforming to the requirements for Thermometer 41C asprescribed in Specification E1, or for Thermometer 81C asprescribed in Specifications
28、for IP Standard Thermometers.Alternatively, temperature-measuring devices of equal or betteraccuracy and precision may be used.6.5 Oxidation Cell Thermometer, A 76 mm immersion LIGhaving a range of 110 C to 130 C, graduated in 0.1 C, totallength of 300 mm 6 5 mm, and stem diameter of 6.0 mm to 7.0mm
29、. Alternatively, temperature-measuring devices or DCT, ofequal or better accuracy and precision may be used. Tempera-ture of the sample shall be measured at 76 mm from the top ofthe sample. See Fig. 2 and Fig. 3.NOTE 1Temperature gradient within the sample may exist from theheating system and temper
30、ature control design.6.6 Wire Coiling Mandrel, as shown in Fig. 4.6.7 Thermometer Bracket, for holding the oxidation cellthermometer, of 18-8 stainless steel, having the dimensionsshown in Fig. 5. The thermometer is held in the bracket by twofluoro-elastomer O-rings of approximately 5 mm inside diam
31、-eter. Alternatively, thin stainless steel wire may be used.6.8 Abrasive Cloth, silicon carbide, 100 grit with clothbacking.6.9 Flexible Tubing, poly vinyl chloride approximately 6.4mm (14 in.) inside diameter with a 2.4 mm (332 in.) wall fordelivery of oxygen to the oxidation cell.6.10 Membrane Fil
32、ters, white, plain, 47 mm in diameter,pore size 1 m. The recommended membrane filters are PTFEand cellulose acetate plus nitrocellulose material.6.11 Filter Holder, 47 mm, consisting of a borosilicate glassfunnel and a funnel base with a coarse grade fritted-glass filtersupport with a length of 40 m
33、 to 60 m, or stainless steelscreen support such that the filter can be clamped between theground-glass sealing surfaces of the funnel and its base bymeans of a metal clamp.6.12 Weighing Bottle, cylindrical body with ground-glassstopper; approximate inside diameter 65 mm, height of body45 mm , capaci
34、ty 60 mL.6.13 Vacuum Source, to provide pressure reduction to13.3 kPa 6 0.7 kPa (100 mm 6 5 mm Hg) absolute pressure.D7873 1322NOTE 1All dimensions are in millimetres (inches).NOTE 2The oxidation test tube has a calibration line at 360 mL. This calibration applies to the test tube alone at 20 C.NOTE
35、 3Open tube ends to be ground and fire-polished.FIG. 1 Oxidation CellD7873 13236.14 Cooling Vessel, A desiccator or other type of tightlycovered vessel for cooling the weighing vessels before weigh-ing. The use of a drying agent is not recommended.6.15 Drying Oven, capable of maintaining a temperatu
36、re of70 C 6 5 C.6.16 Forceps, having unserrated tips.6.17 Rubber Policeman.6.18 Pipette Bulb.7. Reagents and Materials7.1 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
37、-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.67.2 Reagent Water, Unless otherwise indicated, reference towater shall be understood to mean distilled, deionized water asdefined by Type I or Type II in Specification D1193 or Grade3 in ISO 3696.7.
38、3 Acetone, Reagent grade. (WarningHealth hazard,flammable.)7.4 Cleaning Reagent, cleaning by a 24 h soak at roomtemperature in a free rinsing liquid acid cleaner with a pH of 2to 4.5.7.5 n-heptane, Reagent grade. (WarningFlammable.Harmful if inhaled.)7.6 Isopropyl Alcohol, Reagent grade. (WarningFla
39、mmable.)7.7 Catalyst Wires,7.7.1 Low-Metalloid Steel Wire1.59 mm (0.0625 in.) indiameter (No. 16 Washburn and Moen Gage).NOTE 2Carbon steel wire, soft bright annealed and free from rust ofGrade 1008 as described in Specification A510M is satisfactory. Similarwire conforming to Specification E230 is
40、also satisfactory7.8 Electrolytic Copper Wire, 1.63 mm (0.064 in.) in diam-eter (No. 16 Imperial Standard Wire Gage or No. 14 AmericanWire Gage), 99.9 % purity, conforming to Specification B1.NOTE 3Alternatively, suitably prepared steel and copper catalyst coilsmay be purchased from a supplier.7.9 D
41、etergent, free rinsing, water-soluble, anionic detergentwith a pH of 9.5 to 11.7.10 Oxygen(WarningOxygen vigorously acceleratescombustion.) 99.5 % minimum purity, with pressure regulationadequate to maintain a constant flow of gas through theapparatus. The use of a two-stage pressure regulator on ta
42、nkoxygen is recommended.8. Sampling8.1 Samples for this test can come from tanks, drums, smallcontainers, or even operating equipment. Therefore, use theapplicable apparatus and techniques described in PracticeD4057.8.2 For one single determination at a specified time theminimum required sample size
43、 is 360 mL. However, 6 to 8tubes will be required to develop the data points to obtain thesludge mass at 25 % or agreed-upon residual RPVOT ratio bylogarithmic interpolation. Therefore, approximately 2200 mLto 2900 mL will be required for this test.6Reagent Chemicals, American Chemical Society Speci
44、fications, AmericanChemical 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 Conven
45、tion, Inc. (USPC), Rockville,MD.FIG. 2 Oxidation Cell with ThermometerFIG. 3 76 mm Immersion LIG ThermometerD7873 13249. Preparation of Apparatus9.1 Cleaning CatalystImmediately prior to winding acatalyst coil, clean a 3.00 m 6 0.01 m length of iron wire andan equal length of copper wire with wads o
46、f absorbent cottonwet with n-heptane and follow by abrasion with abrasive clothuntil a fresh metal surface is exposed. Then wipe with dryabsorbent cotton until all loose particles of metal and abrasivehave been removed. In subsequent operations, handle thecatalyst wires with clean gloves (cotton, ru
47、bber, or plastic) toprevent contact with the skin.9.2 Preparation of Catalyst CoilTwist the iron and copperwires tightly together at one end for three turns and then windthem simultaneously alongside each other on a threadedmandrel (see Fig. 4), inserting the iron wire in the deeperthread. Remove th
48、e coil from the mandrel, twist the free endsof the iron and copper wires together for three turns, and bendthe twisted ends to conform to the shape of the spiral coil. Theoverall length of the finished coil should be 225 mm 6 5mm(8.9 in. 6 0.2 in.). If necessary, the coil may be stretched togive the
49、 required length (Note 4).NOTE 4The finished catalyst coil is a double spiral of copper and ironwire, 225 mm 6 5 mm (8.9 in. 6 0.2 in.) overall length and 15.9 mm to16.5 mm (0.625 in. to 0.650 in.) inside diameter. The turns of wire areevenly spaced, and two consecutive turns of the same wire are 3.96 mm to4.22 mm (0.156 in. to 0.166 in.) apart, center to center. The mandrelshown in Fig. 4 is designed to produce such a coil. Using this mandrel, theiron wire is wound on a thread of 14.98 mm (0.590 in.) diameter, while thecopper
