1、Designation: D7624 10D7624 18Standard Test Method forCondition Monitoring of Nitration in In-Service Petroleumand Hydrocarbon-Based Lubricants by Trend AnalysisUsing Fourier Transform Infrared (FT-IR) Spectrometry1This standard is issued under the fixed designation D7624; the number immediately foll
2、owing 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. Scope Scope*1.1 This test
3、 method covers monitoring nitration in gasoline and natural gas engine oils as well as in other types of lubricantswhere nitration by-products may form due to the combustion process or other routes of formation of nitration compounds.1.2 This test method uses FT-IR spectroscopy for monitoring build-
4、up of nitration by-products in in-service petroleum andhydrocarbon-based lubricants as a result of normal machinery operation. Nitration levels in gasoline and natural gas engine oilsrise as combustion by-products react with the oil as a result of exhaust gas recirculation or a blow-by. This test me
5、thod is designedas a fast, simple spectroscopic check for monitoring of nitration in in-service petroleum and hydrocarbon-based lubricants with theobjective of helping diagnose the operational condition of the machine based on measuring the level of nitration in the oil.1.3 Acquisition of FT-IR spec
6、tral data for measuring nitration in in-service oil and lubricant samples is described in PracticeD7418. In this test method, measurement and data interpretation parameters for nitration using both direct trend analysis anddifferential (spectral subtraction) trend analysis are presented.1.4 This tes
7、t method is based on trending of spectral changes associated with nitration in in-service petroleum andhydrocarbon-based lubricants. For direct trend analysis, values are recorded directly from absorption spectra and reported in unitsof 100*absorbance per 0.1 mm 0.1 mm pathlength (or equivalently ab
8、sorbance units per centimetre). For differential trend analysis,values are recorded from the differential spectra (spectrum obtained by subtraction of the spectrum of the reference oil from thatof the in-service oil) and reported in units of 100*absorbance per 0.1 mm pathlength (or equivalently abso
9、rbance units percentimetre). Warnings or alarm limits can be set on the basis of a fixed maximum value for a single measurement or, alternatively,can be based on a rate of change of the response measured. (1)2 In either case, such maintenance action limits should be determinedthrough statistical ana
10、lysis, history of the same or similar equipment, round robin tests or other methods in conjunction with thecorrelation of nitration changes to equipment performance.NOTE 1It is not the intent of this test method to establish or recommend normal, cautionary, warning or alert limits for any machinery.
11、 Such limitsshould be established in conjunction with advice and guidance from the machinery manufacturer and maintenance group.1.5 This test method is for petroleum and hydrocarbon-based lubricants and is not applicable for ester-based oils, includingpolyol esters or phosphate esters.1.6 The values
12、 stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6.1 ExceptionThe unit for wave numbers is cm-1.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the u
13、ser of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardizationestabl
14、ished in the Decision on Principles for the Development of International Standards, Guides and Recommendations 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
15、Lubricants and is the direct responsibility of SubcommitteeD02.96.03 on FTIR Testing Practices and Techniques Related to In-Service Lubricants.Current edition approved Aug. 1, 2010Dec. 1, 2018. Published September 2010February 2019. Originally approved in 2010. Last previous edition approved in 2010
16、 asD7624 10. DOI: 10.1520/D762410.10.1520/D7624-18.2 The boldface numbers in parentheses refer to a list of references at the end of this standard.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the pr
17、evious 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 ASTM is to be considered the official document.*A Summary of C
18、hanges 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:3D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation o
19、f Dynamic Viscosity)D2896 Test Method for Base Number of Petroleum Products by Potentiometric Perchloric Acid TitrationD5185 Test Method for Multielement Determination of Used and Unused Lubricating Oils and Base Oils by InductivelyCoupled Plasma Atomic Emission Spectrometry (ICP-AES)D6304 Test Meth
20、od for Determination of Water in Petroleum Products, Lubricating Oils, and Additives by Coulometric KarlFischer TitrationD7412 Test Method for Condition Monitoring of PhosphateAntiwearAdditives in In-Service Petroleum and Hydrocarbon BasedLubricants by Trend Analysis Using Fourier Transform Infrared
21、 (FT-IR) SpectrometryD7414 Test Method for Condition Monitoring of Oxidation in In-Service Petroleum and Hydrocarbon Based Lubricants byTrend Analysis Using Fourier Transform Infrared (FT-IR) SpectrometryD7415 Test Method for Condition Monitoring of Sulfate By-Products in In-Service Petroleum and Hy
22、drocarbon BasedLubricants by Trend Analysis Using Fourier Transform Infrared (FT-IR) SpectrometryD7418 Practice for Set-Up and Operation of Fourier Transform Infrared (FT-IR) Spectrometers for In-Service Oil ConditionMonitoringE131 Terminology Relating to Molecular SpectroscopyE177 Practice for Use
23、of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE2412 Practice for Condition Monitoring of In-Service Lubricants by TrendAnalysis Using Fourier Transform Infrared (FT-IR)Spectrometry3. Terminology3.1
24、 Definitions:3.1.1 For definitions of terms relating to infrared spectroscopy used in this test method, refer to Terminology E131. Fordefinition of terms related to in-service oil condition monitoring, refer to Practice D7418.3.1.2 machinery health, na qualitative expression of the operational statu
25、s of a machine sub-component, component or entiremachine, used to communicate maintenance and operational recommendations or requirements in order to continue operation,schedule maintenance or take immediate maintenance action.4. Summary of Test Method4.1 This test method uses FT-IR spectrometry to
26、monitor nitration levels in in-service petroleum and hydrocarbon-basedlubricants. The FT-IR spectra of in-service oil samples are collected according to the protocol for either direct trend analysis ordifferential trend analysis described in Practice D7418, and the levels of nitration are measured u
27、sing the peak height measurementsdescribed herein.5. Significance and Use5.1 There is a wide variety of nitration compounds that may be produced and accumulate when oils react with gaseous nitratesformed during the engine combustion process. These nitration products may increase the viscosity, acidi
28、ty and insolubles in theoil, which may lead to ring sticking and filter plugging. Monitoring of nitration products is therefore an important parameter indetermining overall machinery health and should be considered in conjunction with data from other tests such as atomic emission(AE) and atomic abso
29、rption (AA) spectroscopy for wear metal analysis (Test Method D5185), physical property tests (TestMethods D445, D6304, and D2896), and other FT-IR oil analysis methods for oxidation (Test Method D7414), sulfate by-products(Test Method D7415), additive depletion (Test Method D7412), and breakdown pr
30、oducts and external contaminants (PracticeE2412), which also assess elements of the oils condition. (1-6)6. Interferences6.1 Very high water levels can interfere with the nitration measurement.6.2 Conjugated ketones, quinones, unsaturated carboxylic acids and carboxylic acid salts (formed due to the
31、 reaction of acidswith overbased oil additives) are also sources of interference.6.3 Some aromatic compounds may interfere as well.7. Apparatus7.1 Fourier transform infrared spectrometer equipped with sample cell, filter (optional), and pumping system (optional) asspecified in Practice D7418.3 For r
32、eferencedASTM 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.D7624 1827.2 FT-IR Spectral Acquisition ParametersSet FT-IR spectral
33、 acquisition parameters according to instructions in PracticeD7418.8. Sampling8.1 Obtain a sample of the in-service oil and a sample of the reference oil (required only for differential trend analysis)according to the protocol described in Practice D7418.9. Preparation of Apparatus9.1 Rinse, flush,
34、and clean the sample cell, inlet lines, and inlet filter according to instructions in Practice D7418.9.2 Monitor cell pathlength as specified in Practice D7418.10. Procedure10.1 Collect a background spectrum according to the procedure specified in Practice D7418.10.2 Differential Trend Analysis Only
35、 Collect the spectrum of a reference oil sample, according to the procedure specified inPractice D7418.10.3 Collect the spectrum of an in-service oil sample according to the procedure specified in Practice D7418.10.4 Data ProcessingAll data are normalized to a pathlength of 0.100 mm according to the
36、 procedure specified in PracticeD7418.11. Calculation of Nitration Values11.1 Procedure A (Direct Trend Analysis)Nitration by the direct trending method is calculated from the oil sample spectrumusing the measurement peak and baseline points listed in Table 1.11.2 Procedure B (Differential Trend Ana
37、lysis)Nitration by the differential trending method is calculated from the differentialspectrum using the measurement peak and baseline points listed in Table 1. Fig. 1 illustrates the band used in the measurementof nitration in the differential spectrum of diesel crankcase oil.11.3 Reporting:11.3.1
38、 Procedure A (Direct Trend Analysis)Values are reported in units of absorbance per centimetre (Abs/cm), calculated asfollows:Nitration in Abs/cm5Nitration in Abs/0.100 mm*100 (1)11.3.2 Procedure B (Differential Trend Analysis)Values are reported in units of absorbance per centimeter (Abs/cm),calcula
39、ted as follows:Nitration in Abs/cm5Nitration in Abs/0.100 mm*100 (2)11.4 Sample CarryoverTo ensure the minimum amount of sample-to-sample cross-contamination or carryover, either aminimum volume of the subsequent sample or a solvent rinse is used to flush out the previous sample. The efficacy of the
40、 flushingprotocol may be assessed by consecutively analyzing an oil having a low (or zero) nitration level (L1, for example, a fresh oil)and a used oil sample having a high nitration level (H1) followed by a second run of the oil sample having a low nitration level(L2) and then calculating the perce
41、nt carryover (PC) as follows:PC5L22L1!/H1#3100 (3)where L1, H1, and L2 are the values measured for nitration (using the parameters given in Table 1) for the samples run in theindicated sequence. The calculated PC should be 5 %.12. Report12.1 TrendingData shall be recorded and reported at selected ti
42、me intervals during the lubricants life. Ideally, nitration valueswould be compared to that of the newly formulated oil and plotted over time to visualize the relative changes in nitration and todetermine when there needs to be an oil change, albeit other parameters may dictate this change earlier.
43、Sampling and reportingtime intervals for nitration are based on the type of machinery and its previous history associated with this parameter.12.2 Statistical Analysis and Alarm LimitsFor statistical analysis and setting alarm limits, refer to Practice E2412, SectionA3,“Distribution Profiles and Sta
44、tistical Analysis.”TABLE 1 Parameters for Measuring Nitration in In-Service Petroleum and Hydrocarbon Based LubricantsMethod Measurement, cm-1 Baseline Point(s), cm-1Procedure A (Direct Trend Analysis) Height at 1630 Minima 1655 to 1640 and 1620 to 1595Procedure B (Differential Trend Analysis) Heigh
45、t at 1630 Minima 1655 to 1640 and 1620 to 1595D7624 18312.3 Effects of Oil FormulationThe compositions of various oil formulations can have an effect on the results reported fornitration value, and values from two different oil formulations should not be compared. Results should be interpreted relat
46、ive tovalues measured for unused oils of the same formulation or trended directly from the sample history.13. Precision and Bias13.1 PrecisionThe precision of the test method has not yet been determined by a formal interlaboratory study. Preliminaryexaminations of repeatability have shown that the d
47、ifference between repetitive results obtained by the same operator in a givenlaboratory applying the same test method with the same apparatus under constant operating conditions on identical test materialwithin short intervals of time would in the long run, in the normal and correct operation of the
48、 test method, through the use of eitherProcedureAor Procedure B, exceed the following value only in one case in 20:this test method is based on an interlaboratory studyof conducted in 2018. 8 laboratories tested 15 different materials. Every “test result” represents an individual determination. Each
49、laboratory was asked to submit 2 replicate test results, from a single operator, for each material. Practice E 691 was followed forthe designRepeatability r!50.078 absorbance units/cm for Procedures Aand B (4)The reproducibility of this test method is being determined and will be available on or beforeand analysis of the data; the de-tails May 1, 2013are given in ASTM Research Report RR:D02-1895.413.1.1 Repeatability Limit (r)the value below which the absolute difference between two individual test results obtained underrepeatability conditions may be expec
