ASTM E839-2011(2016) red 2914 Standard Test Methods for Sheathed Thermocouples and Sheathed Thermocouple Cable.pdf

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1、Designation: E839 11E839 11 (Reapproved 2016)Standard 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, t

2、he 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 document lists methods for testing Mineral-Insulated, Metal-Sheathed (MIMS) thermocouple assemblies an

3、dthermocouple cable, but does not require that any of these tests be performed nor does it state criteria for acceptance. Theacceptance criteria are given in other ASTM standard specifications that impose this testing for those thermocouples and cable.Examples from ASTM thermocouple specifications f

4、or acceptance criteria are given for many of the tests. These tabulated valuesare not necessarily those that would be required to meet these tests, but are included as examples only.1.2 These tests are intended to support quality control and to evaluate the suitability of sheathed thermocouple cable

5、 orassemblies for specific applications. Some alternative test methods to obtain the same information are given, since in a givensituation, an alternative test method may be more practical. Service conditions are widely variable, so it is unlikely that all the testsdescribed will be appropriate for

6、a given thermocouple application. A brief statement is made following each test description toindicate when it might be used.1.3 The tests described herein include test methods to measure the following properties of sheathed thermocouple material andassemblies.1.3.1 Insulation Properties:1.3.1.1 Com

7、pactiondirect method, absorption method, and tension method.1.3.1.2 Thickness. Thickness.1.3.1.3 ResistanceatResistanceat room temperature and at elevated temperature.1.3.2 Sheath PropertiesProperties:1.3.2.1 Integritytwo water test methods and mass spectrometer.1.3.2.2 Dimensionslength, diameter, a

8、nd roundness.1.3.2.3 Wall thickness. Wall thickness.1.3.2.4 SurfacegrossSurfacegross visual, finish, defect detection by dye penetrant, and cold-lap detection by tension test.1.3.2.5 Metallurgical structure. Metallurgical structure.1.3.2.6 DuctilitybendDuctilitybend test and tension test.1.3.3 Therm

9、oelement Properties:1.3.3.1 Calibration. Calibration.1.3.3.2 Homogeneity. Homogeneity.1.3.3.3 Drift. Drift.1.3.3.4 Thermoelement diameter, roundness, and surface appearance. Thermoelement diameter, roundness, and surfaceappearance.1.3.3.5 Thermoelement spacing. Thermoelement spacing.1.3.3.6 Thermoel

10、ement ductility. Thermoelement ductility.1.3.3.7 Metallurgical structure. 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 end moisture seal, and defect detection by dye penetrant.

11、1.3.4.3 Electricalcontinuity, loop resistance, and connector polarity.1.3.4.4 Radiographic inspection. Radiographic inspection.1 These test methods are under the jurisdiction of ASTM Committee E20 on Temperature Measurement and is the direct responsibility of Subcommittee E20.04 onThermocouples.Curr

12、ent edition approved Nov. 1, 2011Nov. 1, 2016. Published January 2012January 2016. Originally approved in 1989. Last previous edition approved in 20052011 asE839 05.E839 11. DOI: 10.1520/E0839-11.10.1520/E0839-11R16.This document is not an ASTM standard and is intended only to provide the user of an

13、 ASTM standard 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 publis

14、hed by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11.3.4.5 Thermoelement diameter. Thermoelement diameter.1.3.4.6 Thermal response time. Thermal response time.1.3.4.7 Thermal cycle. T

15、hermal cycle.1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-c

16、onformance with the standard.1.5 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 and determine the applicability of regulatorylimitations p

17、rior to use.2. Referenced Documents2.1 ASTM Standards:2E3 Guide for Preparation of Metallographic SpecimensE94 Guide for Radiographic ExaminationE112 Test Methods for Determining Average Grain SizeE165 Practice for Liquid Penetrant Examination for General IndustryE177 Practice for Use of the Terms P

18、recision and Bias in ASTM Test MethodsE207 Test Method for Thermal EMF Test of Single Thermoelement Materials by Comparison with a Reference Thermoelementof Similar EMF-Temperature PropertiesE220 Test Method for Calibration of Thermocouples By Comparison TechniquesE230 Specification and Temperature-

19、Electromotive Force (EMF) Tables for Standardized ThermocouplesE235 Specification for Thermocouples, Sheathed, Type K and Type N, for Nuclear or for Other High-Reliability ApplicationsE344 Terminology Relating to Thermometry and HydrometryE585/E585M Specification for Compacted Mineral-Insulated, Met

20、al-Sheathed, Base Metal Thermocouple CableE608/E608M Specification for Mineral-Insulated, Metal-Sheathed Base Metal ThermocouplesE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE780 Test Method for Measuring the Insulation Resistance of Mineral-Insula

21、ted, Metal-Sheathed Thermocouples andThermocouple Cable at Room TemperatureE1025 Practice for Design, Manufacture, and Material Grouping Classification of Hole-Type Image Quality Indicators (IQI)Used for RadiologyE1129/E1129M Specification for Thermocouple ConnectorsE1350 Guide for Testing Sheathed

22、Thermocouples, Thermocouples Assemblies, and Connecting Wires Prior to, and AfterInstallation or ServiceE1684 Specification for Miniature Thermocouple ConnectorsE1751 Guide for Temperature Electromotive Force (EMF) Tables for Non-Letter Designated Thermocouple Combinations(Withdrawn 2009)3E2181/E218

23、1M Specification for Compacted Mineral-Insulated, Metal-Sheathed, Noble Metal Thermocouples and Thermo-couple Cable2.2 ANSI StandardB 46.1 Surface Texture42.3 Other StandardUSAEC Division of Reactor Development and Technology RDT Standard C 2-1T Determination of Insulation Compaction inCeramic Insul

24、ated Conductors August 19703. Terminology3.1 DefinitionsThe definitions given in Terminology E344 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 cable produced from the same raw material lots after completion of

25、fabrication.3.2.2 cable lot, na quantity of finished mineralinsulated, metal-sheathed thermocouple cable manufactured from tubing orother sheath material from the same heat, wire from the same spool and heat, and insulation from the same batch, then assembledand processed together under controlled p

26、roduction conditions to the required final outside diameter.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.3

27、 The last approved version of this historical standard is referenced on www.astm.org.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.E839 11 (2016)23.2.3 cold-lap, nsheath surface defect where the sheath surface has been galled and torn by

28、 a drawing die and the torn surfacesmoothed by a subsequent diameter reduction.3.2.4 insulation compaction density, nthe density of a compacted powder is the combined density of the powder particles andthe voids remaining after the powder compaction. Sometimes the insulation compaction density is di

29、vided by the theoreticaldensity of the powder particles to obtain a dimensionless fraction of theoretical density as a convenient method to express therelative compaction.3.2.5 raw material, ntubing or other sheath material, insulation and wires used in the fabrication of sheathed thermocouplecable.

30、3.2.6 short range ordering, nthe reversible short-ranged, order-disorder transformation in which the nickel and chromiumatoms occupy specific (ordered) localized sites in the Type EP or Type KP thermoelement alloy crystal structure.3.2.7 thermal response time, nthe time required for a sheathed therm

31、ocouple signal to attain the specified percent of the totalvoltage change produced by a step change of temperature at the sheaths outer surface.4. Summary of Test Methods4.1 Insulation Properties:4.1.1 CompactionThese tests ensure that the insulation is compacted sufficiently (1) to prevent the insu

32、lation from shiftingduring use with the possibility of the thermoelements shorting to each other or to the sheath, and (2) to have good heat transferbetween the sheath and the thermoelements.4.1.2 Insulation ResistanceThe insulation shall be free of moisture and contaminants that would compromise th

33、evoltage-temperature relationship or shorten the useful life of the sheathed thermocouple. Measurement of insulation resistance isa useful way to detect the presence of unacceptable levels of impurities in the insulation.4.2 Sheath Properties:4.2.1 IntegrityThese tests ensure that (1) the sheath wil

34、l be impervious to moisture and gases so the insulation andthermoelements will be protected, (2) surface flaws and cracks that might develop into sheath leaks are detected, and (3) the sheathwalls are as thick as specified.4.2.2 DimensionsDetermination of length, diameter, and sheath roundness are o

35、ften necessary to assure proper dimensionalfit.4.2.3 Sheath DuctilityThe sheath shall be ductile enough to bend the required amount without breaking or cracking.4.3 Thermoelement Properties Service Life:4.3.1 CalibrationThis test ensures that the temperature-emf relationship initially corresponds to

36、 standardized tolerances.4.3.2 SizeThe thermocouple sheath and thermoelement sizes are related to the service life and the thermoelement spacing isrelated to possible low insulation resistance or shorting.4.3.3 Thermoelement DuctilityDuctility of the thermoelements shall be sufficient to allow the a

37、ssembly to be bent duringassembly or service without significant damage to the thermoelements.4.4 Thermocouple Assembly PropertiesThe criteria listed above shall apply to both thermocouple assemblies and to bulkcable. In addition, the following tests are important for thermocouple assemblies.4.4.1 C

38、ontinuityThe loop continuity test assures that the thermocouple assembly has a completed circuit.4.4.2 Loop ResistanceThe loop resistance test can detect shorted or damaged thermoelements.4.4.3 PolarityThe connector polarity test indicates whether the connector is correctly installed.4.4.4 Moisture

39、SealThe moisture seal at the reference junction end of the thermocouple, if faulty, may allow contaminationof the insulation with moisture or gases.4.4.5 RadiographyRadiographic examination of the junction and sheath closure weld can indicate faulty junctions and sheathclosures that will lead to ear

40、ly failure. Most internal dimensions can also be measured from the radiograph.4.4.6 Response TimeThe thermal response time gives an indication of the quickness with which an installed thermocouple willsignal a changing temperature under the test conditions.4.4.7 Thermal CycleThe thermal cycle test w

41、ill offer assurance that the thermocouple will not have early failure because ofstrains imposed from temperature transients.5. Significance and Use5.1 This standard provides a description of test methods used in otherASTM specifications to establish certain acceptable limitsfor characteristics of th

42、ermocouple assemblies and thermocouple cable. These test methods define how those characteristics shallbe determined.5.2 The usefulness and purpose of the included tests are given for the category of tests.5.3 WarningUsers should be aware that certain characteristics of thermocouples might change wi

43、th time and use. If athermocouples designed shipping, storage, installation, or operating temperature has been exceeded, that thermocouples moistureseal may have been compromised and may no longer adequately prevent the deleterious intrusion of water vapor. Consequently,E839 11 (2016)3the thermocoup

44、les condition established by test at the time of manufacture may not apply later. In addition, inhomogeneities candevelop in thermoelements because of exposure to higher temperatures, even in cases where maximum exposure temperatures havebeen lower than the suggested upper use temperature limits spe

45、cified in Table 1 of Specification E608/E608M. For this reason,calibration of thermocouples destined for delivery to a customer is not recommended. Because the EMF indication of anythermocouple depends upon the condition of the thermoelements along their entire length, as well as the temperature pro

46、file patternin the region of any inhomogeneity, the EMF output of a used thermocouple will be unique to its installation. Because temperatureprofiles in calibration equipment are unlikely to duplicate those of the installation, removal of a used thermocouple to a separateapparatus for calibration is

47、 not recommended. Instead, in situ calibration by comparison to a similar thermocouple known to begood is often recommended.6. General Requirements6.1 All the inspection operations are to be performed under clean conditions that will not degrade the insulation, sheath, orthermoelements. This include

48、s the use of suitable gloves when appropriate.6.2 During all process steps in which insulation is exposed to ambient atmosphere, the air shall be clean, with less than 50 %relative humidity, and at a temperature between 20 and 26C (68 and 79F).6.3 All samples which are tested shall be identified by

49、material code, and shall be traceable to a production run.7. Insulation Properties7.1 Insulation Compaction DensityThe thermal conductivity of the insulation, as well as the ability of the insulation to lockthe thermoelements into place, will be affected by the insulation compaction density.7.1.1 A direct method for measuring insulation compaction density is applicable if a representative sample can be sectioned sothat the sample ends are perpendicular to the sample length and the sheath, thermoelements, and insulation form a smoot