ASTM D6595-2000(2011) 9375 Standard Test Method for Determination of Wear Metals and Contaminants in Used Lubricating Oils or Used Hydraulic Fluids by Rotating Disc Electrode Atomi.pdf

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1、Designation: D6595 00 (Reapproved 2011)Standard Test Method forDetermination of Wear Metals and Contaminants in UsedLubricating Oils or Used Hydraulic Fluids by Rotating DiscElectrode Atomic Emission Spectrometry1This standard is issued under the fixed designation D6595; the number immediately follo

2、wing the designation 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method

3、covers the determination of wearmetals and contaminants in used lubricating oils and usedhydraulic fluids by rotating disc electrode atomic emissionspectroscopy (RDE-AES).1.2 This test method provides a quick indication for abnor-mal wear and the presence of contamination in new or usedlubricants an

4、d hydraulic fluids.1.3 This test method uses oil-soluble metals for calibrationand does not purport to relate quantitatively the values deter-mined as insoluble particles to the dissolved metals. Analyticalresults are particle size dependent and low results may beobtained for those elements present

5、in used oil samples as largeparticles.1.4 The test method is capable of detecting and quantifyingelements resulting from wear and contamination ranging fromdissolved materials to particles approximately 10 m in size.1.5 The values stated in SI units are to be regarded asstandard. No other units of m

6、easurement are included in thisstandard.1.5.1 The preferred units are mg/kg (ppm by mass).1.6 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 practic

7、es and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampling of Petroleum andPetroleum Products3. Terminology3.1 Definitions:3.1.1 burn, vtin emission spectroscopy, to vaporize andexcite a specimen with suffi

8、cient energy to generate spectralradiation.3.1.2 calibration, nthe determination of the values of thesignificant parameters by comparison with values indicated bya set of reference standards.3.1.3 calibration curve, nthe graphical or mathematicalrepresentation of a relationship between the assigned

9、(known)values of standards and the measured responses from themeasurement system.3.1.4 calibration standard, na standard having an ac-cepted value (reference value) for use in calibrating a measure-ment instrument or system.3.1.5 emission spectroscopy, nmeasurement of energyspectrum emitted by or fr

10、om an object under some form ofenergetic stimulation; for example, light, electrical discharge,and so forth.3.2 Definitions of Terms Specific to This Standard:3.2.1 arc discharge, na self-sustaining, high current den-sity, high temperature discharge, uniquely characterized by acathode fall nearly eq

11、ual to the ionization potential of the gasor vapor in which it exists.3.2.2 check sample, na reference material usually pre-pared by a laboratory for its own use as a calibration standard,as a measurement control standard, or for the qualification of ameasurement method.3.2.3 contaminant, nmaterial

12、in an oil sample that maycause abnormal wear or lubricant degradation.3.2.4 counter electrode, neither of two graphite electrodesin an atomic emission spectrometer across which an arc orspark is generated.3.2.5 graphite disc electrode, na soft form of the elementcarbon manufactured into the shape of

13、 a disc for use as acounter electrode in arc/spark spectrometers for oil analysis.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved May 1, 2011. P

14、ublished August 2011. Originallyapproved in 2000. Last previous edition approved in 2005 as D659500(2005).DOI: 10.1520/D6595-00R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informa

15、tion, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.6 graphite rod electrode, na soft form of the elementcarbon manufactured into the shape of a rod for use as aco

16、unter electrode in arc/spark spectrometers for oil analysis.3.2.7 profiling, nto set the actual position of the entranceslit to produce optimum measurement intensity.3.2.8 standardization, nthe process of reestablishing andcorrecting a calibration curve through the analysis of at leasttwo known oil

17、standards.3.2.9 uptake rate, nthe amount of oil sample that isphysically carried by the rotating disc electrode into the arc foranalysis.3.2.10 wear metal, nmaterial resulting from damage to asolid surface due to relative motion between that surface and acontacting substance or substances.4. Summary

18、 of Test Method4.1 Wear metals and contaminants in a used oil test speci-men are evaporated and excited by a controlled arc dischargeusing the rotating disk technique. The radiant energies ofselected analytical lines and one or more references arecollected and stored by way of photomultiplier tubes,

19、 chargecoupled devices or other suitable detectors. A comparison ismade of the emitted intensities of the elements in the used oiltest specimen against those measured with calibration stan-dards. The concentrations of the elements present in the oil testspecimen are calculated and displayed. They ma

20、y also beentered into a data base for processing.5. Significance and Use5.1 Used Lubricating OilThe determination of debris inused oil is a key diagnostic method practiced in machinecondition monitoring programs. The presence or increase inconcentration of specific wear metals can be indicative of t

21、heearly stages of wear if there are baseline concentration data forcomparison.Amarked increase in contaminant elements can beindicative of foreign materials in the lubricants, such asantifreeze or sand, which may lead to wear or lubricantdegradation. The test method identifies the metals and theirco

22、ncentration so that trends relative to time or distance can beestablished and corrective action can be taken prior to moreserious or catastrophic failure.6. Interferences6.1 SpectralMost spectral interferences can be avoided byjudicious choice of spectral lines. High concentrations ofadditive elemen

23、ts can have an interfering influence on thespectral lines used for determining wear metals. Instrumentmanufacturers usually compensate for spectral interferencesduring factory calibration. A background correction system,which subtracts unwanted intensities on either side of thespectral line, shall a

24、lso be used for this purpose. When spectralinterferences cannot be avoided with spectral line selection andbackground correction, the necessary corrections shall be madeusing the computer software supplied by the instrument manu-facturer.6.2 Viscosity EffectsDifferences in viscosity of used oilsampl

25、es will cause differences in uptake rates. Internal refer-ences of the instrument will compensate for a portion of thedifferences. In used oil applications, the hydrogen 486.10 nmspectral line has become the industry standard for use as aninternal reference. Without a reference, trended data on used

26、 oilwill be adversely affected if the sample base stock has adifferent viscosity from the base line samples.6.3 ParticulateWhen large particles over 10 m in sizeare detected, the analytical results will be lower than the actualconcentration they represent. Large particles may not beeffectively trans

27、ported by the rotating disk electrode sampleintroduction system into the arc, nor will they be fullyvaporized by the spark.7. Apparatus7.1 Electrode SharpenerAn electrode sharpener is neces-sary to remove the contaminated portion of the rod electroderemaining from the previous determination. It also

28、 forms a new160 angle on the end of the electrode. Electrode sharpenersare not required for instruments using a pre-shaped discelectrode as the counter electrode.7.2 Rotating Disc Electrode Atomic Emission Spectrometer,a simultaneous spectrometer consisting of excitation source,polychromator optics,

29、 and a readout system. Suggested ele-ments and wavelengths are listed in Table 1. When multiplewavelengths are listed, they are in the order of preference ordesired analytical range.7.3 Heated Ultrasonic Bath (Recommended), an ultrasonicbath to heat and homogenize used oil samples to bring particles

30、into homogeneous suspension. The ultrasonic bath shall beused on samples containing large amount of debris and thosethat have been in transit or stored for 48 hours or longer.8. Reagents and Materials8.1 Base Oil, a 75 cSt base oil free of analyte to be used asa calibration blank or for blending cal

31、ibration standards.8.2 Check Samples, An oil standard or sample of knownconcentration which is periodically analyzed as a go/no gosample to confirm the need for standardization based on anallowable 610 % accuracy limit.8.3 Cleaning Solution, An environmentally safe, non-chlorinated, rapid evaporatin

32、g, and non-film producing solvent,to remove spilled or splashed oil sample in the sample stand.8.4 Disc Electrode, a graphite disc electrode of high-puritygraphite (spectroscopic grade). Dimensions of the electrodesshall conform to those shown in Fig. 1.TABLE 1 Elements and Recommended WavelengthsEl

33、ement Wavelength, nm Element Wavelength, nmAluminum 308.21 Nickel 341.48Barium 230.48, 455.40 Phosphorus 255.32, 214.91Boron 249.67 Potassium 766.49Calcium 393.37, 445.48 Silicon 251.60Chromium 425.43 Silver 328.07, 243.78Copper 324.75, 224.26 Sodium 588.89, 589.59Iron 259.94 Tin 317.51Lead 283.31 T

34、itanium 334.94Lithium 670.78 Tungsten 400.87Manganese 403.07, 294.92 Vanadium 290.88, 437.92Magnesium 280.20, 518.36 Zinc 213.86Molybdenum 281.60D6595 00 (2011)28.5 Glass Cleaning Solution, capable of cleaning and re-moving splashed oil sample from the quartz window thatprotects the entrance lens an

35、d fiber optic. Isopropyl rubbingalcohol or ammonia based window cleaner has been found tobe suitable for this purpose.8.6 Organometallic Standards, single or multi-elementblended standards for use as the high concentration standardfor instrument standardization purposes or for use as a checksample t

36、o confirm calibration. Typical concentrations in theupper calibration point standard for used oil applications is 100mg/kg for wear metals and contaminants, and 900 mg/kg foradditive elements.8.6.1 Standards have a shelf-life and shall not be used tostandardize an instrument if they have exceeded th

37、e expirationdate.8.7 Counter ElectrodeThe counter electrode can be eithera rod or a disc. The counter electrode must be high-puritygraphite (spectroscopic grade). Dimensions of the counterelectrodes shall conform to those shown in Fig. 2.8.8 Specimen HoldersA variety of specimen holders canbe used f

38、or the analysis of used oil samples. Disposablespecimen holders must be discarded after each analysis andreusable specimen holders must be cleaned after each analysis.All specimen holders must be free of contamination and shallbe stored accordingly. Specimen holder and covers shall beused on hydraul

39、ic oil samples that may catch on fire during theanalysis.9. Sampling9.1 The used oil sample taken for the analysis must berepresentative of the entire system. Good sampling proceduresare key to good analyses and samples must be taken inaccordance with Practice D4057.10. Preparation of Test Specimen1

40、0.1 HomogenizationUsed oil samples may contain par-ticulate matter and, in order to be representative, must alwaysbe vigorously shaken prior to pouring a test specimen foranalysis.10.2 Ultrasonic HomogenizationSamples that have beenin transit for several days, idle in storage or very viscous, shallb

41、e placed in a heated ultrasonic bath to break up clusters ofparticles and to bring them back into suspension. The samplesshall be vigorously shaken after being in the ultrasonic bathand prior to pouring a test specimen for analysis. The bathtemperature shall be at least 60C and the total agitation t

42、imeat least 2 min.10.3 Specimen HoldersUsed oil samples and oil standardsshall be poured into a specimen holder of at least 1 mLcapacityprior to analysis. Exercise care to pour the sample consistentlyto the same level in the specimen holders to maintain goodrepeatability of analysis.10.4 Specimen Ta

43、bleThe specimen table shall be adjustedso that when it is in the fully raised position, at least one-thirdof the disc electrode is immersed in the oil test specimen.11. Preparation of Apparatus11.1 Warm-up BurnsIf the instrument has been idle forseveral hours, it may be necessary to conduct at least

44、 threewarm-up burns to stabilize the excitation source. The warm-upprocedure can be performed with any oil sample or standard.Consult the manufacturers instructions for specific warm-uprequirements.11.2 Optical ProfilePerform the normal optical profileprocedure called for in the operation manual of

45、the instrument.An optical profile shall also be performed if the instrument hasbeen inoperative for an extended period of time or if thetemperature has shifted more than 10C since the last calibra-tion check.11.3 Validation CheckA go/no go standardization checkcan be performed with one or more check

46、 samples to confirmcalibration prior to the analysis of routine samples. A calibra-tion standard or known oil sample can be used for this purpose.The optical profile and standardization routine recommendedby the instrument manufacturer shall be performed if thevalidation check fails to meet the 610

47、% accuracy guidelinesfor each element of interest.12. Calibration12.1 Factory CalibrationThe analytical range for eachelement is established through the analysis of organometallicstandards at known concentrations.Acalibration curve for eachelement is established and correction factors are set to pro

48、ducea linear response. Analyses of test specimens must be per-formed within the linear range of response. The typicalelements and recommended wavelengths determined in theused oil analysis applications are listed in Table 1.12.2 Routine StandardizationA minimum of a two pointroutine standardization

49、shall be performed if the instrumentfails the validation check or at the start of each working shift.A minimum of three analyses shall be made using the blankand working standard.13. Procedure13.1 Analysis of Oil SamplesAnalyze the test specimen inthe same calibration curve program and manner as the stan-dardization standards. A new disc electrode and re-pointed rodelectrode or new counter disc electrode must be used for eachanalysis. A laboratory grade paper towel or installation toolshall be used to install the disc electrode in order to protec