1、Designation: E608/E608M 13Standard Specification forMineral-Insulated, Metal-Sheathed Base MetalThermocouples1This standard is issued under the fixed designation E608/E608M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the requirements for mineral-insulated, metal-sheathed base metal thermocouples for indus
3、-trial or high-reliability applications. It applies specifically tothermocouples fabricated from sheathed thermocouple mate-rial in accordance with Specification E585/E585M. The speci-fication provides for the selection of thermoelements,insulation, sheath material, measuring junction configuration,
4、thermocouple assembly length, and the type of transition ortermination.1.2 This specification also includes provisions for eitherquality assurance or verification program requirements, orboth, as a purchasers option.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separ
5、ately as standard. The values 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.1.4 This standard does not purport to address all of thesafety concerns
6、, if any, associated with its 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:2E165 Practice for Liquid Penetrant Examinat
7、ion for GeneralIndustryE220 Test Method for Calibration of Thermocouples ByComparison TechniquesE230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized ThermocouplesE344 Terminology Relating to Thermometry and Hydrom-etryE585/E585M Specification for Compacted Mineral-Insu
8、lated, Metal-Sheathed, Base Metal ThermocoupleCableE780 Test Method for Measuring the Insulation Resistanceof Mineral-Insulated, Metal-Sheathed Thermocouples andThermocouple Cable at Room TemperatureE839 Test Methods for Sheathed Thermocouples andSheathed Thermocouple Cable2.2 AWS Standards:3A5.9 Sp
9、ecification for Corrosion-Resisting Chromium andChromium-Nickel Steel Welding Rods and Bare Elec-trodesA5.14 Specification for Nickel and Nickel-Alloy Bare Weld-ing Rods and Electrodes3. Terminology3.1 DefinitionsThe definitions given in Terminology E344shall apply to this specification.3.2 Definiti
10、ons of Terms Specific to This Standard:3.2.1 common ungrounded junction, nmeasuring junc-tions within the same multi-pair thermocouple that are electri-cally isolated from the sheath but electrically connected to eachother.3.2.2 isolated ungrounded junction, nmeasuring junctionswithin the same multi
11、-pair thermocouple that are electricallyisolated from the sheath and electrically isolated from eachother.3.2.3 lot, na quantity of thermocouples manufacturedfrom the same continuous length of mineral-insulated, metal-sheathed thermocouple cable.3.2.4 sheathed thermocouple material, na combination o
12、ftwo or more continuous thermoelements embedded in ceramicinsulation compacted within a metal protecting sheath.1This specification is under the jurisdiction of ASTM Committee E20 onTemperature Measurement and is the direct responsibility of Subcommittee E20.04on Thermocouples.Current edition approv
13、ed Nov. 1, 2013. Published December 2013. Originallyapproved in 1977. Last previous edition approved in 2006 as E608/E608M - 06.DOI: 10.1520/E0608_E0608M-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AS
14、TMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Welding Society (AWS), 550 NW LeJeune Rd.,Miami, FL 33126, http:/www.aws.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Un
15、ited States14. Significance and Use4.1 This specification describes the physical requirements ofmineral-insulated, metal-sheathed base metal thermocouplesand establishes suitable test criteria for their evaluation.4.2 Standardized dimensional requirements and acceptableallowances for manufacturing v
16、ariations, are given.4.3 Aset of standard tests to be applied to all thermocouplescovered by this specification are described, in addition tooptional tests from which applicable additional requirementsmay be selected.4.4 WarningUsers should be aware that certain charac-teristics of thermocouples mig
17、ht change with time and use.4.4.1 If a thermocouples designed shipping, storage,installation, or operating temperature has been exceeded, thethermocouples moisture seal may have been compromised andmay no longer prevent the deleterious intrusion of water vapor.Consequently, the thermocouples conditi
18、on established by testat the time of manufacture may not apply later after anextended period of use, and retesting may become necessary.4.4.2 In addition, inhomogeneities can develop in thermo-elements because of exposure to temperature, even in caseswhere the maximum exposure temperatures have been
19、 lowerthan the suggested upper temperature limits of Table 1. For thisreason, calibration of thermocouples destined for delivery to acustomer is not recommended (see S6.1).4.4.3 Furthermore, because the EMF indication of anythermocouple depends upon the condition of the thermoele-ments along their e
20、ntire length, as well as the temperatureprofile pattern in the region of any inhomogeneity, the EMFoutput of a used thermocouple will be unique to its installation.Because temperature profiles in calibration equipment areunlikely to duplicate those of the installation, removal of a usedthermocouple
21、to a separate apparatus for calibration is notrecommended. Instead, in-situ calibration by comparison to asimilar thermocouple of known accuracy is recommended.5. Ordering Information5.1 The purchase documents shall specify the following:5.1.1 The type and quantity of thermoelement pairs, and thetol
22、erances, if other than standard (see 6.4 and 6.5).5.1.2 The nominal sheath diameter. See Table 1 or Specifi-cation E585/E585M for preferred nominal diameters.5.1.3 The insulating material (either MgO or Al2O3) and itsrespective type. See Specification E585/E585M.5.1.4 The sheath material. See Specif
23、ication E585/E585M.5.1.5 The style of measuring junction: Style G (grounded)or Style U (ungrounded). See Figs. 1 and 2. If more than onepair of thermoelements is specified, Style U is further subdi-vided into Style CU (common ungrounded) and Style IU(isolated ungrounded).45.1.6 The quantity, length,
24、 and length tolerance of eachthermocouple. See Figs. 3-6 for examples.5.1.7 The type and configuration of connection head,connector, transition piece, or termination, and moisture sealrequired on the end opposite the measuring junction. See Figs.3-6 for examples. The minimum and maximum intendedoper
25、ating temperature of the connection head, transition, ortermination, and moisture seal should be specified (6.6). Forthermocouples with insulated wire attached (Fig. 6) and StyleU junctions, state the minimum acceptable insulation resis-tance (6.7).5.1.8 Optional supplementary testing requirements a
26、nd testsample rate (8.2), if applicable.5.1.9 Quality assurance and quality verification programrequirements, if applicable. See Appendix X1.5.1.10 Any deviations from this specification or the refer-enced specifications.4Style G, Style U, Style CU, and Style IU measuring junctions were previouslyte
27、rmed Class 1, Class 2, Class 2A, and Class 2B measuring junctions respectively.TABLE 1 Suggested Upper Temperature Limits for Sheathed ThermocouplesNOTE 1This table gives the suggested upper temperature limits for the various thermocouples in several common sheath sizes. It does not take intoaccount
28、 environmental temperature limitations of the sheath material itself, nor does it address compatibility considerations between the thermoelementmaterials and the sheath containing them. The actual maximum practical temperature in a particular situation will generally be limited to the lowesttemperat
29、ure among the several factors involved. The purchaser should consult ASTM Manual 125and other literature sources for further informationabout applications.NOTE 2The temperature limits given here are intended only as a guide to the purchaser and should not be taken as absolute values nor as guarantee
30、sof satisfactory life or performance. These types and sizes are sometimes used at temperatures above the given limits, but usually at the expense of stabilityor service life, or both. In other instances, it may be necessary to reduce the given limits in order to achieve adequate service.Upper Temper
31、ature Limit for Various Sheath Diameters C FNominal Sheath Diameter Thermocouple Typemm in. T J E K, N0.5 0.020 260 (500) 260 (500) 300 (570) 700 (1290). . . 0.032 260 (500) 260 (500) 300 (570) 700 (1290)1.0 0.040 260 (500) 260 (500) 300 (570) 700 (1290)1.5 0.062 260 (500) 440 (825) 510 (950) 920 (1
32、690)2.0 . . . 260 (500) 440 (825) 510 (950) 920 (1690). . . 0.093 260 (500) 480 (900) 580 (1075) 1000 (1830)3.0 0.125 315 (600) 520 (970) 650 (1200) 1070 (1960)4.5 0.188 370 (700) 620 (1150) 730 (1350) 1150 (2100)6.0 0.250 370 (700) 720 (1330) 820 (1510) 1150 (2100)8.0 0.375 370 (700) 720 (1330) 820
33、 (1510) 1150 (2100)E608/E608M 132Dimensions Referenced in Section 7Dimension Feature NameA End Closure DiameterD Minimum Material ThicknessE End Closure ThicknessFIG. 1 Grounded Measuring Junction, Style GDimensions Referenced in Section 7Dimension Feature NameA End Closure DiameterB Measuring Junct
34、ion LengthC Minimum Measuring Junction InsulationThickness, Radial DimensionD Minimum Material ThicknessE End Closure ThicknessF Measuring Junction LocationFIG. 2 Ungrounded Measuring Junction, Style UFIG. 3 Sheathed ThermocoupleFIG. 4 Sheathed Thermocouple with Exposed WiresE608/E608M 1335.1.11 Shi
35、pping method and straightness criteria, if required(see 10.2).55.1.12 The minimum and maximum intended operatingtemperatures of the thermocouple (see S6.1).6. General Requirements6.1 TaggingDuring fabrication, each thermocouple shallbe tagged with a unique identification number to maintaintraceabili
36、ty to materials and test data. The producers standardtagging method may be used.6.2 Welding RodFiller material used for welding or plug-ging the end closure shall comply with Table 2.6.3 Measuring Junctions:6.3.1 The end closure shall be impervious to gases andliquids. There shall be no cracks, hole
37、s, or voids that penetratethrough the metal wall. Any mineral oxide removed duringfabrication of the measuring junction shall be replaced with dryoxide of the same type that is in accordance with the purityrequirements of Specification E585/E585M. Style U measuringjunctions shall be fabricated by we
38、lding the thermoelementswithout filler metal or flux.6.3.2 The measuring junction end closures shall be sealedby welding. The use of plugs or filler metals is optional.6.4 Standard TolerancesSheathed thermocouples fabri-cated to this specification shall conform to the standardtolerances (see Table 3
39、) in accordance with Specification E230,unless otherwise specified.6.5 Special TolerancesIf specified in the purchasedocument, the special tolerances (see Table 3) in accordancewith Specification E230 shall apply.6.6 TerminationThe sheathed thermocouples shall be ter-minated at their reference junct
40、ion end (the end opposite themeasuring junction end) as specified by the purchaser. Allexposed MgO or Al2O3shall be sealed from moisture to keepthe insulation dry. All connectors, connection heads, or transi-tions shall include a positive method of preventing strain on thethermoelements emerging fro
41、m the sheathed material. Alltransitional wire connections shall be brazed or welded. Themoisture seal and termination (see Figs. 3-6) shall be compat-ible with their intended installation and operating conditions(see 5.1.7).6.7 Room Temperature Insulation Resistance (Style UJunctions)The minimum roo
42、m temperature electrical insula-tion resistance between the thermoelement pairs and the sheathfor sheathed thermocouples with Style U junctions shall be asspecified in Table 4 for the dc test voltage noted. In addition,for Style IU (isolated ungrounded) junctions, the minimumelectrical insulation sp
43、ecified in Table 4 shall also applybetween thermoelement pairs. The minimum insulation valueshall be negotiated between the purchaser and the producer forFig. 6 assemblies with purchaser-specified insulated thermo-couple extension wire or other devices attached. For Fig. 5assemblies, the minimum ins
44、ulation resistance values of Table4 shall be imposed before the thermocouple is terminated(when it is like Fig. 4). The insulation resistance shall be testedin accordance with Test Method E780.6.8 Sheath ConditionThe surface of the completed ther-mocouples shall be visually clean and dry.6.9 The tes
45、ts specified in 8.1 are required to determine if thespecification requirements have been met. Additional optionalrequirements are listed in the Supplementary Requirementssection and may be included in the purchase order require-ments as desired by the purchaser.6.10 All testing and inspection shall
46、be performed in accor-dance with Test Methods E839 unless otherwise indicated.7. Measuring Junction Configuration7.1 The measuring junction configurations are shown incross section in Figs. 1 and 2. The tip shape is optional as longas the dimensional requirements are maintained. The preferrednominal
47、 sheath diameters are listed in Table 1 or SpecificationE585/E585M. The measuring junction dimensional require-ments are as follows:7.1.1 Dimension A, End closure Diameter, Styles U andGThe end closure maximum diameter shall be no larger thanthe nominal sheath diameter plus a weld allowance of 0.05
48、mm(0.002 in.) or 2 % of the nominal sheath diameter, whichever is5“Manual on the Use of Thermocouples in Temperature Measurement,” ASTMManual 12, ASTM International, 1993.FIG. 5 Sheathed Thermocouple Assembly with Connector orConnection Head (Any Type Specified)FIG. 6 Sheathed Thermocouple Assembly
49、with Transition PieceTABLE 2 Weld Closure Filler MetalSheath MaterialWeld Rod AWSTypeAWSSpecifica-tionAustenitic Stainless SteelsTP 304 ER 308 A5.9TP 304L ER 308L A5.9TP 310 ER 310 A5.9TP 316 ER 316 A5.9TP 316L ER 316L A5.9TP 317 ER 317 A5.9TP 321 ER 347 A5.9TP 347 ER 347 A5.9TP 348 ER 348 A5.9Nickel-chromium-iron alloy ER NiCrFe-5 A5.14E608/E608M 134larger. Localized reduction of the end closure diameter causedby weld shrinkage shall not exceed 0.05 mm (0.002 in.) or 2 %of the nominal sheath diameter, whichever is larger. Thisexpanded end closure diametr
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