1、Designation: D6595 16D6595 17Standard 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 following the d
2、esignation 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. Scope*1.1 This test method covers th
3、e determination of wear metals and contaminants in used lubricating oils and used hydraulic fluidsby rotating disc electrode atomic emission spectroscopy (RDE-AES).1.2 This test method provides a quick indication for abnormal wear and the presence of contamination in new or used lubricantsand hydrau
4、lic fluids.1.3 This test method uses oil-soluble metals for calibration and does not purport to relate quantitatively the values determinedas insoluble particles to the dissolved metals. Analytical results are particle size dependent and low results may be obtained forthose elements present in used
5、oil samples as large particles.1.4 The test method is capable of detecting and quantifying elements 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 as standard. No other units of measur
6、ement are included in this standard.1.5.1 The preferred units are mg/kg (ppm by mass).1.6 This standard does not 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 a
7、nd determine the applicability of regulatorylimitations prior to use.1.7 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 Recommend
8、ations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition
9、approved July 1, 2016May 1, 2017. Published July 2016May 2017. Originally approved in 2000. Last previous edition approved in 20112016 asD6595D6595 16. 00 (2011). DOI: 10.1520/D6595-16. DOI: 10.1520/D6595-17.This document is not an ASTM standard and is intended only to provide the user of an ASTM st
10、andard an indication of what changes have been made to the previous version. 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 A
11、STM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12. Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampli
12、ng of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum Products3. Terminology3.1 Definitions:3.1.1 burn, vtin emission spectroscopy, to vaporize and excite a specimen with sufficient energy to generate spectral radiation.3.1.2 calibration, nthe determi
13、nation of the values of the significant parameters by comparison with values indicated by a setof reference standards.3.1.3 calibration curve, nthe graphical or mathematical representation of a relationship between the assigned (known) valuesof standards and the measured responses from the measureme
14、nt system.3.1.4 calibration standard, na standard having an accepted value (reference value) for use in calibrating a measurementinstrument or system.3.1.5 emission spectroscopy, nmeasurement of energy spectrum emitted by or from an object under some form of energeticstimulation; for example, light,
15、 electrical discharge, and so forth.3.2 Definitions of Terms Specific to This Standard:3.2.1 arc discharge, na self-sustaining, high current density, high temperature discharge, uniquely characterized by a cathodefall nearly equal to the ionization potential of the gas or vapor in which it exists.3.
16、2.2 check sample, na reference material usually prepared by a laboratory for its own use as a calibration standard, as ameasurement control standard, or for the qualification of a measurement method.3.2.3 contaminant, nmaterial in an oil sample that may cause abnormal wear or lubricant degradation.3
17、.2.4 counter electrode, neither of two graphite electrodes in an atomic emission spectrometer across which an arc or sparkis generated.3.2.5 graphite disc electrode, na soft form of the element carbon manufactured into the shape of a disc for use as a counterelectrode in arc/spark spectrometers for
18、oil analysis.3.2.6 graphite rod electrode, na soft form of the element carbon manufactured into the shape of a rod for use as a counterelectrode in arc/spark spectrometers for oil analysis.3.2.7 profiling, nto set the actual position of the entrance slit to produce optimum measurement intensity.3.2.
19、8 standardization, nthe process of reestablishing and correcting a calibration curve through the analysis of at least twoknown oil standards.3.2.9 uptake rate, nthe amount of oil sample that is physically carried by the rotating disc electrode into the arc for analysis.3.2.10 wear metal, nmaterial r
20、esulting from damage to a solid surface due to relative motion between that surface and acontacting substance or substances.4. Summary of Test Method4.1 Wear metals and contaminants in a used oil test specimen are evaporated and excited by a controlled arc discharge usingthe rotating disk technique.
21、 The radiant energies of selected analytical lines and one or more references are collected and storedby way of photomultiplier tubes, charge coupled devices charge-coupled devices, or other suitable detectors.Acomparison is madeof the emitted intensities of the elements in the used oil test specime
22、n against those measured with calibration standards. Theconcentrations of the elements present in the oil test specimen are calculated and displayed. They may also be entered into a database for processing.5. Significance and Use5.1 Used Lubricating OilThe determination of debris in used oil is a ke
23、y diagnostic method practiced in machine conditionmonitoring programs. The presence or increase in concentration of specific wear metals can be indicative of the early stages ofwear if there are baseline concentration data for comparison. A marked increase in contaminant elements can be indicative o
24、fforeign materials in the lubricants, such as antifreeze or sand, which may lead to wear or lubricant degradation. The test methodidentifies the metals and their concentration so that trends relative to time or distance can be established and corrective action canbe taken prior to more serious or ca
25、tastrophic failure.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.D6595 1726. Interferences6.1 SpectralMost
26、spectral interferences can be avoided by judicious choice of spectral lines. High concentrations of additiveelements can have an interfering influence on the spectral lines used for determining wear metals. Instrument manufacturers usuallycompensate for spectral interferences during factory calibrat
27、ion. A background correction system, which subtracts unwantedintensities on either side of the spectral line, shall also be used for this purpose. When spectral interferences cannot be avoidedwith spectral line selection and background correction, the necessary corrections shall be made using the co
28、mputer softwaresupplied by the instrument manufacturer.6.2 Viscosity EffectsDifferences in viscosity of used oil samples will cause differences in uptake rates. Internal references ofthe instrument will compensate for a portion of the differences. In used oil applications, the hydrogen 486.10 nm spe
29、ctral line hasbecome the industry standard for use as an internal reference. Without a reference, trended data on used oil will be adverselyaffected if the sample base stock has a different viscosity from the base line samples.6.3 ParticulateWhen large particles over 10 m in size are detected, the a
30、nalytical results will be lower than the actualconcentration they represent. Large particles may not be effectively transported by the rotating disk electrode sample introductionsystem into the arc, nor will they be fully vaporized by the spark.7. Apparatus7.1 Electrode SharpenerAn electrode sharpen
31、er is necessary to remove the contaminated portion of the rod electroderemaining from the previous determination. It also forms a new 160 angle on the end of the electrode. Electrode sharpeners arenot required for instruments using a pre-shaped disc electrode as the counter electrode.7.2 Rotating Di
32、sc Electrode Atomic Emission Spectrometer, a simultaneous spectrometer consisting of excitation source,polychromator optics, and a readout system. Suggested elements and wavelengths are listed in Table 1.When multiple wavelengthsare listed, they are in the order of preference or desired analytical r
33、ange.7.3 Heated Ultrasonic Bath (Recommended), an ultrasonic bath to heat and homogenize used oil samples to bring particles intohomogeneous suspension. The ultrasonic bath shall be used on samples containing large amountamounts of debris and those thathave been in transit or stored for 48 h or long
34、er.8. Reagents and Materials8.1 Base Oil, a 75 cSt base oil free of analyte to be used as a calibration blank or for blending calibration standards.8.2 Check Samples, An oil standard or sample of known concentration which is periodically analyzed as a go/no go go/no-gosample to confirm the need for
35、standardization based on an allowable 610 % accuracy limit.8.3 Cleaning Solution, An environmentally safe, non-chlorinated, rapid evaporating, and non-film producing solvent, to removespilled or splashed oil sample in the sample stand.8.4 Disc Electrode, a graphite disc electrode of high-purity grap
36、hite (spectroscopic grade). Dimensions of the electrodes shallconform to those shown in Fig. 1.8.5 Glass Cleaning Solution, capable of cleaning and removing splashed oil sample from the quartz window that protects theentrance lens and fiber optic. Isopropyl rubbing alcohol or ammonia based ammonia-b
37、ased window cleaner has been found to besuitable for this purpose.8.6 Organometallic Standards, single or multi-element blended standards for use as the high concentration standard forinstrument standardization purposes or for use as a check sample to confirm calibration. Typical concentrations in t
38、he uppercalibration point standard for used oil applications is 100 mgkg for wear metals and contaminants, and 900 mgkg for additiveelements.TABLE 1 Elements and Recommended WavelengthsElement Wavelength, nm Element Wavelength, nmAluminum 308.21 Nickel 341.48Barium 230.48, 455.40 Phosphorus 255.32,
39、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 Titanium 334.94Lithium 670.78 Tungsten 400.87Manganese 403.07, 294.92 Vanadium 290.88, 437.92Magnesium 280.20, 518
40、.36 Zinc 213.86Molybdenum 281.60D6595 1738.6.1 Standards have a shelf-life shelf life and shall not be used to standardize an instrument if they have exceeded the expirationdate.8.7 Counter ElectrodeThe counter electrode can be either a rod or a disc. The counter electrode must be high-purity graphi
41、te(spectroscopic grade). Dimensions of the counter electrodes shall conform to those shown in Fig. 2.8.8 Specimen HoldersA variety of specimen holders can be used for the analysis of used oil samples. Disposable specimenholders must be discarded after each analysis and reusable specimen holders must
42、 be cleaned after each analysis. All specimenholders must be free of contamination and shall be stored accordingly. Specimen holder and covers shall be used on hydraulic oilsamples that may catch on fire during the analysis.8.9 Quality Control Samples, preferably are portions of one or more liquid p
43、etroleum materials that are stable and representativeof the samples of interest. These QC samples can be used to check the validity of the testing process as described in Section 13.9. Sampling9.1 The used oil sample taken for the analysis must be representative of the entire system. Good sampling p
44、rocedures are keyto good analyses and samples must be taken in accordance with Practice D4057 or D4177.10. Preparation of Test Specimen10.1 HomogenizationUsed oil samples may contain particulate matter and, in order to be representative, must always bevigorously shaken prior to pouring a test specim
45、en for analysis.10.2 Ultrasonic HomogenizationSamples that have been in transit for several days, idle in storage, or very viscous,viscousshall be placed in a heated ultrasonic bath to break up clusters of particles and to bring them back into suspension. The samplesshall be vigorously shaken after
46、being in the ultrasonic bath and prior to pouring a test specimen for analysis. The bath temperatureshall be at least 60 C and the total agitation time at least 2 min.10.3 Specimen HoldersUsed oil samples and oil standards shall be poured into a specimen holder of at least 1 mL capacityprior to anal
47、ysis. Exercise care to pour the sample consistently to the same level in the specimen holders to maintain goodrepeatability of analysis.10.4 Specimen TableThe specimen table shall be adjusted so that when it is in the fully raised position, at least one-third ofthe disc electrode is immersed in the
48、oil test specimen.11. Preparation of Apparatus11.1 Warm-up BurnsIf the instrument has been idle for several hours, it may be necessary to conduct at least three warm-upburns to stabilize the excitation source. The warm-up procedure can be performed with any oil sample or standard. Consult themanufac
49、turers instructions for specific warm-up requirements.TABLE 2 RepeatabilityNOTE 1X = mean concentration in mg/kg.Element Range, mg/kg Repeatability, mg/kgAluminum 0.23101 0.5419(X+0.57)0.45Barium 28115 0.0694X1.18Boron 0.14120 0.4280(X+0.1028)0.56Calcium 3.711460 0.1106(X+2.184)Chromium 0.18152 0.7285(X+0.0557)0.41Copper 0.47100 0.1631(X+0.3459)0.85Iron 4.8210 0.3159 (X+0.0141)0.73Lead 0.43101 1.062(X+0.6015)0.34Magnesium 4.91360 0.1049XManganese 0.3117 0.7017(X+0.3534)0.34Molybdenum 0.21100 0.9978(X+0.4795)0.34Nickel 0.35100 0.71
