ASTM E839-2011 1875 Standard Test Methods for Sheathed Thermocouples and Sheathed Thermocouple Cable 《铠装热电偶和铠装热电偶电缆的标准试验方法》.pdf

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1、Designation: E839 11Standard Test Methods forSheathed Thermocouples and Sheathed ThermocoupleCable1This standard is issued under the fixed designation E839; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.

2、 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 document lists methods for testing Mineral-Insulated, Metal-Sheathed (MIMS) thermocouple assembliesand thermocouple cable, but

3、does not require that any of thesetests be performed nor does it state criteria for acceptance. Theacceptance criteria are given in other ASTM standard specifi-cations that impose this testing for those thermocouples andcable. Examples from ASTM thermocouple specifications foracceptance criteria are

4、 given for many of the tests. Thesetabulated values are not necessarily those that would berequired to meet these tests, but are included as examples only.1.2 These tests are intended to support quality control and toevaluate the suitability of sheathed thermocouple cable orassemblies for specific a

5、pplications. Some alternative testmethods to obtain the same information are given, since in agiven situation, an alternative test method may be morepractical. Service conditions are widely variable, so it isunlikely that all the tests described will be appropriate for agiven thermocouple applicatio

6、n. A brief statement is madefollowing each test description to indicate when it might beused.1.3 The tests described herein include test methods tomeasure the following properties of sheathed thermocouplematerial and assemblies.1.3.1 Insulation Properties:1.3.1.1 Compactiondirect method, absorption

7、method,and tension method.1.3.1.2 Thickness.1.3.1.3 Resistanceat room temperature and at elevatedtemperature.1.3.2 Sheath Properties:1.3.2.1 Integritytwo water test methods and mass spec-trometer.1.3.2.2 Dimensionslength, diameter, and roundness.1.3.2.3 Wall thickness.1.3.2.4 Surfacegross visual, fi

8、nish, defect detection bydye penetrant, and cold-lap detection by tension test.1.3.2.5 Metallurgical structure.1.3.2.6 Ductilitybend test and tension test.1.3.3 Thermoelement Properties:1.3.3.1 Calibration.1.3.3.2 Homogeneity.1.3.3.3 Drift.1.3.3.4 Thermoelement diameter, roundness, and surfaceappear

9、ance.1.3.3.5 Thermoelement spacing.1.3.3.6 Thermoelement ductility.1.3.3.7 Metallurgical structure.1.3.4 Thermocouple Assembly Properties:1.3.4.1 Dimensionslength, diameter, and roundness.1.3.4.2 Surfacegross visual, finish, reference junction endmoisture seal, and defect detection by dye penetrant.

10、1.3.4.3 Electricalcontinuity, loop resistance, and connec-tor polarity.1.3.4.4 Radiographic inspection.1.3.4.5 Thermoelement diameter.1.3.4.6 Thermal response time.1.3.4.7 Thermal cycle.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values

11、stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its

12、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.2. Referenced Documents2.1 ASTM Standards:2E3 Guide for Preparation of Metallographic SpecimensE94 Guide for Radiogr

13、aphic ExaminationE112 Test Methods for Determining Average Grain Size1These test methods are under the jurisdiction of ASTM Committee E20 onTemperature Measurement and is the direct responsibility of Subcommittee E20.04on Thermocouples.Current edition approved Nov. 1, 2011. Published January 2012. O

14、riginallyapproved in 1989. Last previous edition approved in 2005 as E839 05. DOI:10.1520/E0839-11.2For referenced ASTM standards, 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 Doc

15、ument Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E165 Practice for Liquid Penetrant Examination for GeneralIndustryE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE207 Tes

16、t Method for Thermal EMF Test of Single Ther-moelement Materials by Comparison with a ReferenceThermoelement of Similar EMF-Temperature PropertiesE220 Test Method for Calibration of Thermocouples ByComparison TechniquesE230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardiz

17、ed ThermocouplesE235 Specification for Thermocouples, Sheathed, Type Kand Type N, for Nuclear or for Other High-ReliabilityApplicationsE344 Terminology Relating to Thermometry and Hydrom-etryE585/E585M Specification for Compacted Mineral-Insulated, Metal-Sheathed, Base Metal ThermocoupleCableE608/E6

18、08M Specification for Mineral-Insulated, Metal-Sheathed Base Metal ThermocouplesE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE780 Test Method for Measuring the Insulation Resistanceof Mineral-Insulated, Metal-Sheathed Thermocouples andThermocouple C

19、able at Room TemperatureE1025 Practice for Design, Manufacture, and MaterialGrouping Classification of Hole-Type Image Quality Indi-cators (IQI) Used for RadiologyE1129/E1129M Specification for Thermocouple Connec-torsE1350 Guide for Testing Sheathed Thermocouples, Ther-mocouplesAssemblies, and Conn

20、ecting Wires Prior to, andAfter Installation or ServiceE1684 Specification for Miniature Thermocouple Connec-torsE1751 Guide for Temperature Electromotive Force (EMF)Tables for Non-Letter Designated Thermocouple Combi-nations3E2181/E2181M Specification for Compacted Mineral-Insulated, Metal-Sheathed

21、, Noble Metal Thermocouplesand Thermocouple Cable2.2 ANSI StandardB 46.1 Surface Texture42.3 Other StandardUSAEC Division of Reactor Development and TechnologyRDT Standard C 2-1T Determination of Insulation Com-paction in Ceramic Insulated Conductors August 19703. Terminology3.1 DefinitionsThe defin

22、itions given in TerminologyE344 shall apply to these test methods.3.2 Definitions of Terms Specific to This Standard:3.2.1 bulk cable, na single length of thermocouple cableproduced from the same raw material lots after completion offabrication.3.2.2 cable lot, na quantity of finished mineralinsulat

23、ed,metal-sheathed thermocouple cable manufactured from tubingor other sheath material from the same heat, wire from thesame spool and heat, and insulation from the same batch, thenassembled and processed together under controlled productionconditions to the required final outside diameter.3.2.3 cold

24、-lap, nsheath surface defect where the sheathsurface has been galled and torn by a drawing die and the tornsurface smoothed by a subsequent diameter reduction.3.2.4 insulation compaction density, nthe density of acompacted powder is the combined density of the powderparticles and the voids remaining

25、 after the powder compaction.Sometimes the insulation compaction density is divided by thetheoretical density of the powder particles to obtain a dimen-sionless fraction of theoretical density as a convenient methodto express the relative compaction.3.2.5 raw material, ntubing or other sheath materi

26、al,insulation and wires used in the fabrication of sheathedthermocouple cable.3.2.6 short range ordering, nthe reversible short-ranged,order-disorder transformation in which the nickel and chro-mium atoms occupy specific (ordered) localized sites in theType EP or Type KP thermoelement alloy crystal

27、structure.3.2.7 thermal response time, nthe time required for asheathed thermocouple signal to attain the specified percent ofthe total voltage change produced by a step change oftemperature at the sheaths outer surface.4. Summary of Test Methods4.1 Insulation Properties:4.1.1 CompactionThese tests

28、ensure that the insulation iscompacted sufficiently (1) to prevent the insulation fromshifting during use with the possibility of the thermoelementsshorting to each other or to the sheath, and (2) to have goodheat transfer between the sheath and the thermoelements.4.1.2 Insulation ResistanceThe insu

29、lation shall be free ofmoisture and contaminants that would compromise thevoltage-temperature relationship or shorten the useful life ofthe sheathed thermocouple. Measurement of insulation resis-tance is a useful way to detect the presence of unacceptablelevels of impurities in the insulation.4.2 Sh

30、eath Properties:4.2.1 IntegrityThese tests ensure that (1) the sheath willbe impervious to moisture and gases so the insulation andthermoelements will be protected, (2) surface flaws and cracksthat might develop into sheath leaks are detected, and (3) thesheath walls are as thick as specified.4.2.2

31、DimensionsDetermination of length, diameter, andsheath roundness are often necessary to assure proper dimen-sional fit.4.2.3 Sheath DuctilityThe sheath shall be ductile enoughto bend the required amount without breaking or cracking.4.3 Thermoelement Properties Service Life:4.3.1 CalibrationThis test

32、 ensures that the temperature-emf relationship initially corresponds to standardized toler-ances.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.E

33、839 1124.3.2 SizeThe thermocouple sheath and thermoelementsizes are related to the service life and the thermoelementspacing is related to possible low insulation resistance orshorting.4.3.3 Thermoelement DuctilityDuctility of the thermoele-ments shall be sufficient to allow the assembly to be bentd

34、uring assembly or service without significant damage to thethermoelements.4.4 Thermocouple Assembly PropertiesThe criteria listedabove shall apply to both thermocouple assemblies and to bulkcable. In addition, the following tests are important forthermocouple assemblies.4.4.1 ContinuityThe loop cont

35、inuity test assures that thethermocouple assembly has a completed circuit.4.4.2 Loop ResistanceThe loop resistance test can detectshorted or damaged thermoelements.4.4.3 PolarityThe connector polarity test indicateswhether the connector is correctly installed.4.4.4 Moisture SealThe moisture seal at

36、the referencejunction end of the thermocouple, if faulty, may allow con-tamination of the insulation with moisture or gases.4.4.5 RadiographyRadiographic examination of the junc-tion and sheath closure weld can indicate faulty junctions andsheath closures that will lead to early failure. Most intern

37、aldimensions can also be measured from the radiograph.4.4.6 Response TimeThe thermal response time gives anindication of the quickness with which an installed thermo-couple will signal a changing temperature under the testconditions.4.4.7 Thermal CycleThe thermal cycle test will offerassurance that

38、the thermocouple will not have early failurebecause of strains imposed from temperature transients.5. Significance and Use5.1 This standard provides a description of test methodsused in other ASTM specifications to establish certain accept-able limits for characteristics of thermocouple assemblies a

39、ndthermocouple cable. These test methods define how thosecharacteristics shall be determined.5.2 The usefulness and purpose of the included tests aregiven for the category of tests.5.3 WarningUsers should be aware that certain charac-teristics of thermocouples might change with time and use. Ifa the

40、rmocouples designed shipping, storage, installation, oroperating temperature has been exceeded, that thermocouplesmoisture seal may have been compromised and may no longeradequately prevent the deleterious intrusion of water vapor.Consequently, the thermocouples condition established by testat the t

41、ime of manufacture may not apply later. In addition,inhomogeneities can develop in thermoelements because ofexposure to higher temperatures, even in cases where maxi-mum exposure temperatures have been lower than the sug-gested upper use temperature limits specified in Table 1 ofSpecification E608/E

42、608M. For this reason, calibration ofthermocouples destined for delivery to a customer is notrecommended. Because the EMF indication of any thermo-couple depends upon the condition of the thermoelementsalong their entire length, as well as the temperature profilepattern in the region of any inhomoge

43、neity, the EMF output ofa used thermocouple will be unique to its installation. Becausetemperature profiles in calibration equipment are unlikely toduplicate those of the installation, removal of a used thermo-couple to a separate apparatus for calibration is not recom-mended. Instead, in situ calib

44、ration by comparison to a similarthermocouple known to be good is often recommended.6. General Requirements6.1 All the inspection operations are to be performed underclean conditions that will not degrade the insulation, sheath, orthermoelements. This includes the use of suitable gloves whenappropri

45、ate.6.2 During all process steps in which insulation is exposedto ambient atmosphere, the air shall be clean, with less than50 % relative humidity, and at a temperature between 20 and26C (68 and 79F).6.3 All samples which are tested shall be identified bymaterial code, and shall be traceable to a pr

46、oduction run.7. Insulation Properties7.1 Insulation Compaction DensityThe thermal conduc-tivity of the insulation, as well as the ability of the insulation tolock the thermoelements into place, will be affected by theinsulation compaction density.7.1.1 A direct method for measuring insulation compac

47、tiondensity is applicable if a representative sample can be sec-tioned so that the sample ends are perpendicular to the samplelength and the sheath, thermoelements, and insulation form asmooth surface free of burrs. The procedure is as follows:7.1.1.1 Weigh the sample section,7.1.1.2 Measure the she

48、ath diameter and length with amicrometer,7.1.1.3 Separate the insulation from the thermoelement andsheath with the use of an air abrasive tool,7.1.1.4 Weigh the thermoelements and sheath, and7.1.1.5 Determine the sheath and thermoelements densitieseither by experiment or from references.7.1.1.6 Dete

49、rmine the percentage of the maximum theoreti-cal insulation density r as follows:%r5100A 2 B!/$0.785 C2D 2 E/F 1 G/H!#J% (1)where:A = total specimen mass, kg or lb,B = sheath and wires mass, kg or lb,C = sheath diameter, m or in.,D = specimen length, m or in.,E = sheath mass, kg or lb,F = sheath density, kg/m3or lb/in.3,G = wires mass, kg or lb,H = wires density (averaged density if applicable), kg/m3or lb/in.3, andJ = maximum theoretical density of the insulation, kg/m3or lb/in.3.7.1.2 Alternately, a liquid absorption method for determin