1、Designation: E 696 07Standard Specification forTungsten-Rhenium Alloy Thermocouple Wire1This standard is issued under the fixed designation E 696; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the requirements for bare,solid conductor, tungsten and rhenium alloy thermoelementshaving diameters of 0.127 mm (0
3、.005 in.) to 0.508 mm (0.020in.) supplied in matched pairs. These thermoelements shall besuitable for use either in bead-insulated, bare-wire thermo-couples, or in compacted metal-sheathed, ceramic insulatedthermocouple material or assemblies.1.2 This specification covers the thermocouple combina-ti
4、ons of tungsten-3 % rhenium versus tungsten-25 % rhenium(W3Re/W25Re) and tungsten-5 % rhenium versus tungsten-26 % rhenium (W5Re/W26Re; Type C). All information ap-plies to both combinations unless otherwise noted.1.3 It is recognized that the alloys described are refractoryand are not suitable for
5、use at high temperatures in oxidizingatmospheres. All tests and processes described herein must beperformed under conditions that are non-reactive to tungsten-rhenium alloys.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.2
6、. Referenced Documents2.1 ASTM Standards:2E8 Test Methods for Tension Testing of Metallic MaterialsE 207 Test Method for Thermal EMF Test of Single Ther-moelement Materials by Comparison with a ReferenceThermoelement of Similar EMF-Temperature PropertiesE 220 Test Method for Calibration of Thermocou
7、ples ByComparison TechniquesE 230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized ThermocouplesE 344 Terminology Relating to Thermometry and Hydrom-etryE 452 Test Method for Calibration of Refractory MetalThermocouples Using a Radiation ThermometerE 988 Temperature-Ele
8、ctromotive Force (EMF) Tables forTungsten-Rhenium ThermocouplesE 1751 Guide for Temperature Electromotive Force (EMF)Tables for Non-Letter Designated Thermocouple Combi-nations3. Terminology3.1 Definitions:3.1.1 For definitions used in this standard, see TerminologyE 344.3.2 Definitions of Terms Spe
9、cific to This Standard:3.2.1 dope, vtin this specification, to add potassium,silicon and aluminum compounds or other volatile substancesto the alloy powders during the preparation to produce a ductilewire. See NASA CR-72884.33.2.1.1 DiscussionSome alloy powders are doped.3.2.2 lot, na quantity of wi
10、re processed or heat treated asa single continuous length and identified uniquely.4. Ordering Information4.1 A purchase order for thermocouple material conformingto this specification shall specify the following:4.1.1 Thermocouple Wire CompositionMay be W3Re/W25Re or W5Re/W26Re.4.1.2 Wire SizeSpecif
11、y size with each order.4.1.3 Wire LengthSpecify total amount of each wire andminimum continuous length.4.1.4 Thermocouple CalibrationCalibration will be inaccordance with Section 5.1.4 unless otherwise specified.4.1.5 Supplementary RequirementsSee the Supplemen-tary Requirements section of this spec
12、ification.4.1.6 Instructions for Spooling, Packaging, and LabelingPackaging will be in accordance with Section 10 unlessotherwise specified.4.1.7 Tests and Certifications Required from theProcessorCertification will be in accordance with Section 9unless otherwise specified.5. Materials and Manufactu
13、re5.1 Thermocouple Wire:1This specification is under the jurisdiction of ASTM Committee E20 onTemperature Measurement and is the direct responsibility of Subcommittee E20.04on Thermocouples.Current edition approved May 1, 2007. Published June 2007. Originallyapproved in 1979. Last previous edition a
14、pproved in 2000 as E 696 00.2For 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 Document Summary page onthe ASTM website.3NASA CR-72884, “Some Studies on
15、Behavior of W-Re Thermocouple Mate-rials at High Temperatures.” Available from National Aeronautics and SpaceAdministration, 400 Maryland Ave. S.W., Washington, DC 20546.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.1 GeneralTh
16、e thermoelements shall be tungsten-3 %rhenium and tungsten-25 % rhenium or tungsten-5 % rheniumand tungsten-26 % rhenium (Type C), as indicated on thepurchase order.5.1.2 Physical:5.1.2.1 The diameter of each wire shall be within 60.01 mm(0.0005 in.) of the ordered size for 0.5 mm (0.02 in.) diamete
17、rwire and smaller. The diameter of each wire shall be uniformend-to-end to within 0.01 mm (0.0005 in.) for 0.5 mm (0.02in.) diameter wire and smaller.5.1.2.2 The wires shall be solid, round, smooth and be freeof weld joints, slivers, kinks, pits or nicks exceeding 5 % ofdiameter.5.1.2.3 The wire sur
18、face shall be uniformly clean and free ofdiscoloration.5.1.2.4 Mechanical or optical methods may be used toverify the requirements of 5.1.2.1, 5.1.2.2, and 5.1.2.3.5.1.3 Mechanical:5.1.3.1 The wires shall withstand, at a temperature of 20 to35 C (68 to 95 F), wrapping five turns around a mandrel fiv
19、etimes the diameter of the wire without breaking or splitting.5.1.3.2 The tests shall be made on at least one specimenfrom each end of each lot of wire.5.1.4 Thermoelectric:5.1.4.1 The emf versus temperature characteristics of thematched thermoelements shall be determined using proceduresdescribed i
20、n Test Methods E 207, E 220 or E 452.5.1.4.2 The emf versus temperature relationship of thematched pair of thermoelements shall comply with the valuesshown in Guide E 1751 for W3Re/W25Re or SpecificationE 230 for Type C (W5Re/W26Re).5.1.4.3 The initial calibration tolerance shall be in accor-dance w
21、ith Table 1 (W3Re/W25Re). or Specification E 230(W5Re/W26Re), as appropriate.5.2 Composition:5.2.1 Positive thermoelement:5.2.1.1 The positive thermoelement for the W3Re/W25Recombination shall have a nominal composition of 97 % tung-sten and 3 % rhenium.5.2.1.2 The positive thermoelement for the W5R
22、e/W26Recombination shall have a nominal composition of 95 % tung-sten and 5 % rhenium.5.2.1.3 The positive thermoelement shall be doped to pro-vide desirable grain structure and workability and maintainductility after high temperature use.5.2.2 Negative thermoelement:5.2.2.1 The negative thermoeleme
23、nt for the W3Re/W25Recombination shall have a nominal composition of 75 % tung-sten and 25 % rhenium.5.2.2.2 The negative thermoelement for the W5Re/W26Recombination shall have a nominal composition of 74 % tung-sten and 26 % rhenium.6. Lot Identification6.1 Thermocouple wires, test results and cert
24、ifications shallbe identified by manufacturers lot number.7. Lot Designation7.1 A vendor who purchases wire from processors forrepackaging and resale shall supply, for each spool, the wireprocessors name, lot number and certification to the customer.8. Extension Wires8.1 Due to the high cost of tung
25、sten-rhenium alloys, todifficulties encountered in obtaining long continuous lengths ofthese alloys and to inherent problems in applications whereductility is important, many users find it advantageous to usecompensating extension wires made of base metal alloys.8.2 Information on upper temperature
26、limits and the suppli-ers guaranteed limits of error for currently available compen-sating extension wires for W3Re/W25Re can be found in Table2. Information on upper temperature limits and the suppliersguaranteed limits of error for currently available compensatingextension wires for W5Re/W26Re can
27、 be found in Specifica-tion E 230.9. Certification9.1 The processor shall supply a certificate with each orderstating the wire composition, size, lot identification and cali-bration information.10. Packaging and Package Marking10.1 Wires typically will be supplied on spools of a nominal100 mm (4 in.
28、) diameter core and boxed individually, unlessTABLE 1 Initial Calibration Tolerances and Suggested Temperature Range for W3Re/W25Re ThermocouplesATemperature Range Initial Calibration ToleranceThermocouple Type C F C (whichever is greater) FW3Re/W25Re 0 to 2315 C 32 to 4200 64.4 or 1 % Note 3ACautio
29、nUsers should be aware that certain characteristics of thermocouple materials including calibration may change in time with use; consequently, test resultsobtained at time of manufacture may not necessarily apply throughout an extended period of use.NOTE 1Initial calibration tolerances in this table
30、 apply to new thermocouple wire, normally in the size range of 0.127 mm (0.005 in.) to 0.508 (0.020in.) mm in diameter (No. 36 to 24 AWG) and used at temperatures not exceeding the suggested upper temperatures of Table 1. If used at highertemperatures these initial calibration tolerances may not app
31、ly.NOTE 2Initial calibration tolerances apply to new wire as delivered to the user and do not allow for calibration drift during use. The magnitude ofsuch changes depends on such factors as wire size, temperature, time of exposure and environment.NOTE 3The F tolerance is 1.8 times larger than the C
32、tolerance at the equivalent C temperature. Note particularly that the percentage toleranceonly applies to the temperature that is expressed in C.NOTE 4Tables 1 and 2 describe suggested upper temperature limits for the thermocouple and extension wires. These limits apply to protectedthermocouples, th
33、at is, thermocouples in atmospheres that are non-reactive to the alloys being used.E696072otherwise requested. Each spool shall be marked to identify thewire composition, diameter, quantity, processors name, spooldesignation and customers purchase order number in a mannerto identify the pair of wire
34、s to be used to form a thermocouplemeeting the calibration requirement.11. Keywords11.1 rhenium; thermocouple; thermoelement; tungstenSUPPLEMENTARY REQUIREMENTSThe following supplementary requirements shall apply only when specified by the purchaser in thepurchase order or contract.S1. MechanicalS1.
35、1 The wires shall have an elongation measured at atemperature in the range of 20 to 35 C (68 to 95 F) of at least12 % as measured over a 50 mm (2 in.) gauge length.S1.2 Elongation shall be determined in accordance with TestMethods E8using a rate of 0.2 mm/mm/min. (0.2 in./in./min.)maximum and a 50 m
36、m (2 in.) gauge length.S1.3 The tests shall be made on at least one specimen fromeach end of each lot of wire.S2. ThermoelectricS2.1 The wires shall be thermoelectrically homogeneous sothat when joined to form a thermocouple whose measuringjunction and reference junction are held at constant tempera
37、-tures, any short-term (less than 1 h) change in the temperatureprofile along the wire within the range from 0 to 1000 C (32to 1832 F) will not produce a change in the thermocoupleoutput signal of more than 100 V.S3. ElectricalS3.1 A dc resistance measurement may be used to verifymechanical integrit
38、y of tungsten-rhenium alloy wires havingdiameters of 0.125 mm (0.005 in.) or larger. Defects cited in5.1.2.2 can cause high local resistance in tungsten alloy wires.S3.2 A dc resistance measurement at 20 C (68 F) shall bemade on an accurately measured reference length of eachthermoelement using an i
39、nstrument and range to yield 61%accuracy to derive a resistance per meter or foot. The wire sizeof the reference length and test pieces of known, practicallengths should be within 0.005 mm (0.0002 in.) of each other.S3.3 The resistance measurement taken according to 12.3.2shall be compared to the dc
40、 resistance measurements of eachmeasured full length of wire.S3.4 The full length resistance per unit length (ohms permeter or foot) of each of the test lengths shall be within 10 %of the value obtained from the reference length.NOTE S1The resistivity of W25Re and that of W26Re is more thandouble th
41、at of either W3Re or W5Re, and all of these alloys have hightemperature coefficients of resistance.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that deter
42、mination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or
43、withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that
44、 your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (
45、single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 2 Initial Calibration Tolerances and Suggested Temperature Ranges for Type W
46、3Re/W25Re Thermocouple CompensatingExtension WiresTemperature RangeDesignation C F Standard Tolerance300P(+) / 300N(-)A0 to 330 32 to 625 60.125mV203(+) / 225(-)B0 to 260 32 to 500 60.110 mVA97.7Ni Bal Cr, Al, and Si versus 96Ni, 4W; U.S. Patent 3,502,510 assigned to Engelhard Industries.B90Ni, 10Cr versus 98Ni, 2Cr; Designation of Hoskins Mfg.E696073
