1、Designation: E235/E235M 12 (Reapproved 2018)Standard Specification forType K and Type N Mineral-Insulated, Metal-SheathedThermocouples for Nuclear or for Other High-ReliabilityApplications1This standard is issued under the fixed designation E235/E235M; the number immediately following the designatio
2、n indicates the yearof original adoption or, in the case of revision, the year 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 requir
3、ements for simplex,compacted mineral-insulated, metal-sheathed (MIMS), Type Kand N thermocouples for nuclear or other high reliabilityservice. Depending on size, these thermocouples are normallysuitable for operating temperatures to 1652F 900C; specialconditions of environment and life expectancy ma
4、y permittheir use at temperatures in excess of 2012F 1100C. Thisspecification was prepared to detail requirements for this typeof MIMS thermocouple for use in nuclear environments, butthey can also be used for laboratory or general commercialapplications where the environmental conditions exceed nor
5、-mal service requirements. The intended use of a MIMSthermocouple in a specific nuclear application will requireevaluation of the compatibility of the thermocouple, includingthe effect of the temperature, atmosphere, and integratedneutron flux on the materials and accuracy of the thermoele-ments in
6、the proposed application by the purchaser.1.2 This specification does not attempt to include allpossible specifications, standards, etc., for materials that maybe used as sheathing, insulation, and thermocouple wires forsheathed-type construction. The requirements of this specifi-cation include only
7、 the austenitic stainless steels and otheralloys as allowed by Specification E585/E585M for sheathing,magnesium oxide or aluminum oxide as insulation, and Type Kand N thermocouple wires for thermoelements (see Note 1).1.3 General DesignNominal sizes of the finished thermo-couples shall be 0.0400 in.
8、, 0.0625 in., 0.125 in., 0.1875 in., or0.250 in. 1.000 mm, 1.500 mm, 3.000 mm, 4.500 mm, or6.000 mm. Sheath dimensions and tolerances for each nominalsize shall be in accordance with Table 1 and Figs. 1 and 2. Themeasuring junction styles for thermocouples covered by thisspecification are as follows
9、:1.3.1 Style G2(grounded)The measuring junction is elec-trically connected to its conductive sheath, and1.3.2 Style U2(ungrounded)The measuring junction iselectrically isolated from its conductive sheath and fromreference ground.1.4 The values stated in either SI units or inch-pound unitsare to be r
10、egarded separately as standard. The values stated ineach system are not exact equivalents or conversions;therefore, each system shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard.1.5 This standard does not purport to address
11、 all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was develope
12、d in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documen
13、ts2.1 ASTM Standards:3A262 Practices for Detecting Susceptibility to IntergranularAttack in Austenitic Stainless SteelsE3 Guide for Preparation of Metallographic SpecimensE45 Test Methods for Determining the Inclusion Content ofSteelE112 Test Methods for Determining Average Grain SizeE165 Practice f
14、or Liquid Penetrant Examination for GeneralIndustryE220 Test Method for Calibration of Thermocouples By1This specification is under the jurisdiction of ASTM Committee E20 onTemperature Measurement and is the direct responsibility of Subcommittee E20.12on Thermocouples - Specifications.Current editio
15、n approved April 1, 2018. Published April 2018. Originallyapproved in 1964. Last previous edition approved in 2012 as E235/E235M 12.DOI: 10.1520/E0235-12R18.2Style G and Style U measuring junctions were previously termed Class 1 andClass 2 measuring junctions respectively.3For referenced ASTM standa
16、rds, 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 Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA
17、19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Te
18、chnical Barriers to Trade (TBT) Committee.1Comparison TechniquesE230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized ThermocouplesE344 Terminology Relating to Thermometry and Hydrom-etryE585/E585M Specification for Compacted Mineral-Insulated, Metal-Sheathed, Base Meta
19、l ThermocoupleCableE780 Test Method for Measuring the Insulation Resistanceof Mineral-Insulated, Metal-Sheathed Thermocouples andMineral-Insulated, Metal-Sheathed Cable at Room Tem-peratureE839 Test Methods for Sheathed Thermocouples andSheathed Thermocouple CableE883 Guide for ReflectedLight Photom
20、icrographyE1652 Specification for Magnesium Oxide and AluminumOxide Powder and Crushable Insulators Used in theManufacture of Base Metal Thermocouples, Metal-Sheathed Platinum Resistance Thermometers, and NobleMetal Thermocouples2.2 ANSI Standard:B46.1 Surface Texture42.3 American Welding Society St
21、andard:A5.9 Specification for Corrosion-Resisting Chromium andChromium-Nickel Steel-Welding Rods and Bare Elec-trodes53. Terminology3.1 The definitions given in Terminology E344 shall applyto this specification.3.2 Definitions of Terms Specific to This Standard:3.2.1 lot, na quantity of finished MIM
22、S thermocouplesmanufactured from the same lot of MIMS cable, then as-sembled and processed at the same time under the samecontrolled production conditions to their required final configu-ration.4. Ordering Information and Basis of Purchase4.1 The purchase order documents shall specify the follow-ing
23、 information:4.1.1 The quantity, length, and nominal diameter of theMIMS thermocouple,4.1.2 The thermocouple type and tolerance on the initialvalues of emf versus temperature per Table 2, if other thanstandard,4.1.3 The type of ceramic insulation required, either alu-mina (Al2O3) or magnesia (MgO),4
24、.1.4 The type of sheath material and other informationrequired (see 5.1.1),4.1.5 The style of thermocouple measuring junction (see1.2),4.1.6 The type of dye-penetrant inspection procedure to beused, and4.1.7 Any deviations from this specification or the refer-enced specifications.5. Materials and Ma
25、nufacture5.1 All materials used shall be in accordance with thefollowing requirements:4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Available from American Welding Society (AWS), 550 NW LeJeune Rd.,Miami, FL 33126, htt
26、p:/www.aws.org.TABLE 1 Dimensions for Style G and U Measuring JunctionsSheath Outside Diameter, A MinimumSheathWall,BMinimumInsulationThickness,CMinimumWireDiameter,DE, Tolerance F, ToleranceNominalTolerancemin max min maxmin maxInches0.0400 0.0390 0.0415 0.006 0.004 0.005 0.006 0.020 0.004 0.0210.0
27、625 0.0615 0.0640 0.009 0.005 0.010 0.009 0.032 0.005 0.0320.1250 0.1240 0.1265 0.012 0.012 0.020 0.012 0.062 0.012 0.0630.1875 0.1865 0.1890 0.020 0.022 0.031 0.020 0.093 0.022 0.0950.2500 0.2480 0.2520 0.030 0.024 0.040 0.030 0.125 0.024 0.125Millimetres1.000 0.975 1.038 0.15 0.10 0.13 0.15 0.51 0
28、.10 0.531.500 1.475 1.538 0.23 0.13 0.25 0.23 0.81 0.13 0.813.000 2.975 3.038 0.30 0.30 0.51 0.30 1.57 0.30 1.604.500 4.475 4.538 0.51 0.56 0.79 0.51 2.36 0.56 2.416.000 5.950 6.050 0.76 0.61 1.02 0.76 3.18 0.61 3.18FIG. 1 Grounded Measuring Junction, Style GFIG. 2 Ungrounded Measuring Junction, Sty
29、le UE235/E235M 12 (2018)25.1.1 Sheath MaterialsThe sheath material used for thethermocouples described in this specification shall meet therequirements of Specification E585/E585M. The purchaser ofthe thermocouples shall specify only the name of the material(seamless or welded), grade, optional requ
30、irements, test reportrequired, and ASTM designation.5.1.1.1 The inclusion level of the sheath shall be determinedby mounting a 1-in. minimum length of a longitudinal sectionof the sheath using Test Methods E45, Microscopical MethodA, for examination. The inclusion level shall be less than 3 Athrough
31、 D, thin or heavy.5.1.1.2 The grain size of the sheath shall be determined bya specimen taken in accordance with Test Methods E112. Grainsize shall be as specified in Table 3, or finer, as determined bythe Comparison Procedure of Test Methods E112.5.1.1.3 Each lot of sheath material used shall be sa
32、mpledusing Practices A262 as follows. Samples shall be tested byPractice A, and further tested as outlined by Table 1 inPractices A262, where screening tests so indicate. Acceptancelevels for these tests shall be agreed upon between thepurchaser and the producer.5.1.2 ThermoelementThermoelements ref
33、erred to in thisspecification shall be Type K or Type N with a standardtolerance on initial values of emf versus temperature asspecified in Table 2 unless otherwise specified by the pur-chaser.NOTE 1The purchaser may specify an alternative type of thermoele-ment as designated in Specification E230 b
34、y indicating this deviation inthe ordering documents. The supplier and the purchaser shall then agreeupon a tolerance.5.1.3 InsulationThe insulating material shall be eithermagnesia (MgO) or alumina (Al2O3) and shall comply withSpecification E1652 Type 1 material requirements:5.1.3.1 A certified ana
35、lysis of the composition of the insu-lating material as supplied to the thermocouple manufacturershall be furnished to the purchaser. The thermocouple manu-facturer shall be responsible for maintaining the purity in thefinished product within the specified limits.5.1.4 Welding RodFiller rod material
36、 used for welding onthe sheath or for welding the end of the thermocouple closedshall comply with the requirements of AWS Specification A5.9for the sheath material specified on the ordering documents.5.2 Processing:5.2.1 CleanlinessThe outer surface of the completed ther-mocouples at the time of del
37、ivery shall be free of residuescontaining nuclear poisons (such as boron and cadmiumcompounds) or foreign substances (such as chlorinecompounds, strong acids or bases, oils, greases, or dust) thatcould become the source of corrosion or chemistry changes ina primary coolant or heat-transfer medium. T
38、he use of com-pounds containing halogens for final cleaning is prohibited.Alcohol, or methyl isobutyl ketone may be used unlessotherwise specified.5.2.2 AnnealingThe sheath of the finished thermocoupleshall be solution annealed and shall not be sensitized.6. Inspection and Test Methods6.1 General Pr
39、ocedureInspect and approve all thermo-couples in accordance with the sampling procedures specifiedin this section and with inspection requirements stated hereinand in referenced specifications. Acceptance of the sampleinspection results does not relieve the thermocouple manufac-turer of the responsi
40、bility that all thermocouples shall conformto all requirements of this specification and the latest issue ofthe referenced specifications.6.1.1 Acceptance of thermocouples manufactured in accor-dance with this specification requires the satisfactory comple-tion of the general tests specified for all
41、 thermocouples andthree additional tests on selected sample thermocouples.6.1.2 Select one sample thermocouple at random from eachgroup of not more than 15 thermocouples from the same lot.Use sections of those sample thermocouples for the testsrequired in 6.7, 6.10.2, and 6.1.1. For the test in 6.10
42、.2,fabricate a measuring junction of the same style as that in theTABLE 2 Tolerances on Initial Values of EMF versus Temperature for MIMS ThermocouplesNOTE 1Tolerances in this table apply to new MIMS thermocouples.NOTE 2Tolerances apply to new material as produced and do not allow for changes in the
43、rmoelectric characteristics of the materials during use. Themagnitude of such changes depends upon such factors as sheath and thermoelement size, temperature, time of exposure, and the environment.NOTE 3Where tolerances are given in percent, the percentage applies to the temperature being measured w
44、hen expressed in degrees Celsius.NOTE 4To determine the tolerance in degrees Fahrenheit, multiply the tolerance in degrees Celsius by 9/5.ThermocoupleTypeTemperature Range TolerancesReference Junction 32F 0CF CStandard Tolerances Special TolerancesF C F CK or N 32 to 2300 0 to 1260 Note 4 The greate
45、r of 2.2C or 0.75 % Note 4 The greater of 1.1C or 0.4 %KA328 to 32 200 to 0 The greater of 2.2C or 2 %BAMIMS the thermocouples are normally supplied to meet the tolerances specified in the table for temperatures above 0C. The same materials, however, may not fall withinthe sub-zero tolerances given
46、in the second section of the table. If materials are required to meet the sub-zero limits, the purchase order shall so state. Selection ofmaterials shall be required.BLittle information is available to justify establishing special tolerances for sub-zero temperatures. Such special sub-zero tolerance
47、s, if required, shall be agreed uponbetween the purchaser and the producer.TABLE 3 Maximum Grain SizesSheath Outside Diameter, in. mm Maximum0.0400 1.000 60.0625 1.5000.1250 3.0000.1875 4.5000.2500 6.0005E235/E235M 12 (2018)3original group. Inspection and testing of this measuringjunction, such as t
48、hat in 6.3, is not required.6.2 Insulation ResistanceMeasure the insulation resis-tance between the thermocouple circuit and the sheath of eachStyle U thermocouple with a sheath length not exceeding 50 ft15 m in accordance with Test Method E780 using the voltagespecified in Table 4 applied in both d
49、irect and reversed polarity.The insulation resistance measured shall exceed that in Table 4.This requirement can also be applied to completed Style Uthermocouples in that the purchaser may select a samplethermocouple from each lot and remove the measuring junctionto perform this test. Exercise due caution to prevent moisturepickup. If the thermocouple fails this test, the lot of thermo-couples shall
