1、Designation: D7873 131Standard 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、.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 methodmay be used to evaluate industrial oils (for example, cir
4、culat-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 this modification.1.3 The values stated in SI units are to be
5、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 standard does not purport to address all of thesafety concerns,
6、 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 been designated by manyregulatory agencies as a hazardous materi
7、al 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 product Ma-terial Safety Data Sheet (MSDS) for details and EP
8、Aswebsitehttp:/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 Standards:2A510M Specification for General Requirements for WireRods
9、and Coarse Round Wire, Carbon Steel (Metric)(Withdrawn 2011)3B1 Specification for Hard-Drawn Copper WireD943 Test Method for Oxidation Characteristics of InhibitedMineral OilsD1193 Specification for Reagent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 Oxidation Stability of Steam Tur-bine Oils by Rotating Pressure Ve
10、sselD4057 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 Specification and Temperature-Electromotive Force(EMF) Tables for Stand
11、ardized Thermocouples2.2 Other Standards:Specification for IP Standard Thermometers4ISO 3696 Water for Analytical Laboratory UseSpecification and Test Methods53. Terminology3.1 Definitions:3.1.1 sludge, na precipitate or sediment from oxidizedmineral oil that is insoluble in n-heptane.1This test met
12、hod is under the jurisdiction of ASTM 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/D7873-13E01.2For referenced ASTM s
13、tandards, 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.3The last approved version of this historical standard is referenced onwww.astm.org
14、.4Available from Energy Institute, 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, Wes
15、t Conshohocken, PA 19428-2959. United States14. 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 time and thesample is analyzed by Test Method D2272 and the insol
16、ublesare 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 insolublematerial of each oil sample is determined gravimetrically by
17、filtration 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 RPVOTresidual ratio or specified time is reported.5. Significance and Use5
18、.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 metals, or both, resulting invarnish formation during field se
19、rvice. 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 between results in this test and fieldvarnish formation are yet to
20、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 test should be usedtogether with other key lubricant performance
21、 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 delivery tube.It is recommended to have a test tube with a calibratio
22、n 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 0.5 C, fitted with a suitable stirring device toprovide a unif
23、orm 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.6.2.1 Studies have suggested that direct sunlight or artificiallig
24、ht 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 are designed andconstructed of metal, or combinations of meta
25、ls 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 closed when no observa-tion is being made.6.2.1.2 If glass heati
26、ng 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 at least 3 L ofoxygen/hour, and an accuracy of 60.1 L/h.6.4 He
27、ating 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 for IP Standard Thermometers.Alternatively, temperature-measur
28、ing 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. Alternatively, temperature-measuring devices or DCT, ofequal
29、 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 temperature control design.6.6 Wire Coiling Mandrel, as shown in Fig
30、. 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-eter. Alternatively, thin stainless steel wire may be used.6.
31、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 Filters, white, plain, 47 mm in diameter,pore size 1 m. The recom
32、mended 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 to 60 m, or stainless steelscreen support such that the filte
33、r 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 , capacity 60 mL.6.13 Vacuum Source, to provide pressure reduction to1
34、3.3 kPa 6 0.7 kPa (100 mm 6 5 mm Hg) absolute pressure.6.14 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.D7873 1312NOTE 1All dimensions are in millimetres (inches).NOTE 2The oxidati
35、on test tube has a calibration line at 360 mL. This calibration applies to the test tube alone at 20 C.NOTE 3Open tube ends to be ground and fire-polished.FIG. 1 Oxidation CellD7873 13136.15 Drying Oven, capable of maintaining a temperature of70 C 6 5 C.6.16 Forceps, having unserrated tips.6.17 Rubb
36、er 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-tee on Analytical Reagents of the American Chemical Society,w
37、here 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 3696.7.3 Acetone, Reagent grade. (WarningHealth hazard,flammable.)7.4
38、 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. (WarningFlammable.)7.7 Catalyst Wires,7.7.1 Low-Metalloid Steel Wire1.59
39、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 also satisfactory7.8 Electrolytic Copper Wire, 1.63 mm (0.064
40、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 Detergent, free rinsing, water-soluble, anionic detergentwith a
41、 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 tankoxygen is recommended.8. Sampling8.1 Samples for this test c
42、an 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 is 360 mL. However, 6 to 8tubes will be required to develop t
43、he 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.9. Preparation of Apparatus9.1 Cleaning CatalystImmediately prior to winding acatalyst coil, clean a 3.00 m 6 0.0
44、1 m length of iron wire and6Reagent Chemicals, American Chemical Society Specifications, 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 t
45、he United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 2 Oxidation Cell with ThermometerFIG. 3 76 mm Immersion LIG ThermometerD7873 1314an equal length of copper wire with wads of absorbent cottonwet with n-heptane and follow by abrasion wi
46、th 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, rubber, or plastic) toprevent contact with the skin.9.2 Preparat
47、ion 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 the coil from the mandrel, twist the free endsof the iron and co
48、pper 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 required length (Note 4).NOTE 4The finished catalyst coil is
49、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 wire is wound on a thread of 15.9 mm (0.625 in.) diameter. Thes
