ASTM E235/E235M-12(2018)
(Specification)Standard Specification for Type K and Type N Mineral-Insulated, Metal-Sheathed Thermocouples for Nuclear or for Other High-Reliability Applications
Standard Specification for Type K and Type N Mineral-Insulated, Metal-Sheathed Thermocouples for Nuclear or for Other High-Reliability Applications
ABSTRACT
This specification covers the requirements for sheathed, Type K and N thermocouples for nuclear service. This specification can be used for sheathed thermocouples which are required for laboratory or general commercial applications where the environmental conditions exceed normal service requirements. The measuring junction styles for thermocouples are as follows: Style G2 (grounded) in which measuring junction is electrically connected to conductive sheaths and Style U2 (ungrounded) in which measuring junctions are electrically isolated from conductive sheaths and from reference ground. Different properties of the sheath such as integrity, cracks, voids, inclusions, surface finish, surface defect, and metallurgical structure shall be determined by performing different tests. Insulation resistance between thermoelements and the sheath shall be measured as well.
SCOPE
1.1 This specification covers the requirements for simplex, compacted mineral-insulated, metal-sheathed (MIMS), Type K and N thermocouples for nuclear or other high reliability service. Depending on size, these thermocouples are normally suitable for operating temperatures to 1652°F [900°C]; special conditions of environment and life expectancy may permit their use at temperatures in excess of 2012°F [1100°C]. This specification was prepared to detail requirements for this type of MIMS thermocouple for use in nuclear environments, but they can also be used for laboratory or general commercial applications where the environmental conditions exceed normal service requirements. The intended use of a MIMS thermocouple in a specific nuclear application will require evaluation of the compatibility of the thermocouple, including the effect of the temperature, atmosphere, and integrated neutron flux on the materials and accuracy of the thermoelements in the proposed application by the purchaser.
1.2 This specification does not attempt to include all possible specifications, standards, etc., for materials that may be used as sheathing, insulation, and thermocouple wires for sheathed-type construction. The requirements of this specification include only the austenitic stainless steels and other alloys as allowed by Specification E585/E585M for sheathing, magnesium oxide or aluminum oxide as insulation, and Type K and N thermocouple wires for thermoelements (see Note 1).
1.3 General Design—Nominal sizes of the finished thermocouples shall be 0.0400 in., 0.0625 in., 0.125 in., 0.1875 in., or 0.250 in. [1.000 mm, 1.500 mm, 3.000 mm, 4.500 mm, or 6.000 mm]. Sheath dimensions and tolerances for each nominal size shall be in accordance with Table 1 and Figs. 1 and 2. The measuring junction styles for thermocouples covered by this specification are as follows:
FIG. 1 Grounded Measuring Junction, Style G
FIG. 2 Ungrounded Measuring Junction, Style U
1.3.1 Style G2 (grounded)—The measuring junction is electrically connected to its conductive sheath, and
1.3.2 Style U2 (ungrounded)—The measuring junction is electrically isolated from its conductive sheath and from reference ground.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each 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 all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommenda...
General Information
Relations
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E235/E235M −12 (Reapproved 2018)
Standard Specification for
Type K and Type N Mineral-Insulated, Metal-Sheathed
Thermocouples for Nuclear or for Other High-Reliability
Applications
This standard is issued under the fixed designation E235/E235M; the number immediately following the designation indicates the year
of 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. Scope 1.3.1 Style G (grounded)—The measuring junction is elec-
trically connected to its conductive sheath, and
1.1 This specification covers the requirements for simplex,
1.3.2 Style U (ungrounded)—The measuring junction is
compacted mineral-insulated, metal-sheathed (MIMS), Type K
electrically isolated from its conductive sheath and from
and N thermocouples for nuclear or other high reliability
reference ground.
service. Depending on size, these thermocouples are normally
1.4 The values stated in either SI units or inch-pound units
suitable for operating temperatures to 1652°F [900°C]; special
are to be regarded separately as standard. The values stated in
conditions of environment and life expectancy may permit
each system are not exact equivalents or conversions;
their use at temperatures in excess of 2012°F [1100°C]. This
specification was prepared to detail requirements for this type therefore,eachsystemshallbeusedindependentlyoftheother.
Combining values from the two systems may result in non-
of MIMS thermocouple for use in nuclear environments, but
they can also be used for laboratory or general commercial conformance with the standard.
applications where the environmental conditions exceed nor-
1.5 This standard does not purport to address all of the
mal service requirements. The intended use of a MIMS
safety concerns, if any, associated with its use. It is the
thermocouple in a specific nuclear application will require
responsibility of the user of this standard to establish appro-
evaluation of the compatibility of the thermocouple, including
priate safety, health, and environmental practices and deter-
the effect of the temperature, atmosphere, and integrated
mine the applicability of regulatory limitations prior to use.
neutron flux on the materials and accuracy of the thermoele-
1.6 This international standard was developed in accor-
ments in the proposed application by the purchaser.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
1.2 This specification does not attempt to include all
Development of International Standards, Guides and Recom-
possible specifications, standards, etc., for materials that may
mendations issued by the World Trade Organization Technical
be used as sheathing, insulation, and thermocouple wires for
Barriers to Trade (TBT) Committee.
sheathed-type construction. The requirements of this specifi-
cation include only the austenitic stainless steels and other
2. Referenced Documents
alloys as allowed by Specification E585/E585M for sheathing,
magnesiumoxideoraluminumoxideasinsulation,andTypeK 2.1 ASTM Standards:
and N thermocouple wires for thermoelements (see Note 1). A262 Practices for Detecting Susceptibility to Intergranular
Attack in Austenitic Stainless Steels
1.3 General Design—Nominal sizes of the finished thermo-
E3 Guide for Preparation of Metallographic Specimens
couples shall be 0.0400 in., 0.0625 in., 0.125 in., 0.1875 in., or
E45 Test Methods for Determining the Inclusion Content of
0.250 in. [1.000 mm, 1.500 mm, 3.000 mm, 4.500 mm, or
Steel
6.000mm].Sheathdimensionsandtolerancesforeachnominal
E112 Test Methods for Determining Average Grain Size
size shall be in accordance with Table 1 and Figs. 1 and 2. The
E165 Practice for Liquid Penetrant Examination for General
measuring junction styles for thermocouples covered by this
Industry
specification are as follows:
E220 Test Method for Calibration of Thermocouples By
1 2
This specification is under the jurisdiction of ASTM Committee E20 on Style G and Style U measuring junctions were previously termed Class 1 and
Temperature Measurement and is the direct responsibility of Subcommittee E20.12 Class 2 measuring junctions respectively.
on Thermocouples - Specifications. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2018. Published April 2018. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1964. Last previous edition approved in 2012 as E235/E235M – 12. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/E0235-12R18. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E235/E235M−12 (2018)
TABLE 1 Dimensions for Style G and U Measuring Junctions
Sheath Outside Diameter, A Minimum Minimum Minimum E, Tolerance F, Tolerance
Sheath Insulation Wire
Tolerance
Wall, Thickness, Diameter,
Nominal min max min max
min max B C D
Inches
0.0400 0.0390 0.0415 0.006 0.004 0.005 0.006 0.020 0.004 0.021
0.0625 0.0615 0.0640 0.009 0.005 0.010 0.009 0.032 0.005 0.032
0.1250 0.1240 0.1265 0.012 0.012 0.020 0.012 0.062 0.012 0.063
0.1875 0.1865 0.1890 0.020 0.022 0.031 0.020 0.093 0.022 0.095
0.2500 0.2480 0.2520 0.030 0.024 0.040 0.030 0.125 0.024 0.125
[Millimetres]
[1.000] [0.975] [1.038] [0.15] [0.10] [0.13] [0.15] [0.51] [0.10] [0.53]
[1.500] [1.475] [1.538] [0.23] [0.13] [0.25] [0.23] [0.81] [0.13] [0.81]
[3.000] [2.975] [3.038] [0.30] [0.30] [0.51] [0.30] [1.57] [0.30] [1.60]
[4.500] [4.475] [4.538] [0.51] [0.56] [0.79] [0.51] [2.36] [0.56] [2.41]
[6.000] [5.950] [6.050] [0.76] [0.61] [1.02] [0.76] [3.18] [0.61] [3.18]
2.2 ANSI Standard:
B46.1 Surface Texture
2.3 American Welding Society Standard:
A5.9 Specification for Corrosion-Resisting Chromium and
Chromium-Nickel Steel-Welding Rods and Bare Elec-
trodes
3. Terminology
3.1 The definitions given in Terminology E344 shall apply
to this specification.
3.2 Definitions of Terms Specific to This Standard:
FIG. 1 Grounded Measuring Junction, Style G
3.2.1 lot, n—a quantity of finished MIMS thermocouples
manufactured from the same lot of MIMS cable, then as-
sembled and processed at the same time under the same
controlledproductionconditionstotheirrequiredfinalconfigu-
ration.
4. Ordering Information and Basis of Purchase
4.1 The purchase order documents shall specify the follow-
ing information:
FIG. 2 Ungrounded Measuring Junction, Style U
4.1.1 The quantity, length, and nominal diameter of the
MIMS thermocouple,
4.1.2 The thermocouple type and tolerance on the initial
values of emf versus temperature per Table 2, if other than
Comparison Techniques
standard,
E230 Specification and Temperature-Electromotive Force
4.1.3 The type of ceramic insulation required, either alu-
(EMF) Tables for Standardized Thermocouples
mina (Al O ) or magnesia (MgO),
2 3
E344 Terminology Relating to Thermometry and Hydrom-
4.1.4 The type of sheath material and other information
etry
required (see 5.1.1),
E585/E585M Specification for Compacted Mineral-
4.1.5 The style of thermocouple measuring junction (see
Insulated, Metal-Sheathed, Base Metal Thermocouple
1.2),
Cable
4.1.6 The type of dye-penetrant inspection procedure to be
E780 Test Method for Measuring the Insulation Resistance
used, and
of Mineral-Insulated, Metal-Sheathed Thermocouples and
4.1.7 Any deviations from this specification or the refer-
Mineral-Insulated, Metal-Sheathed Cable at Room Tem-
enced specifications.
perature
E839 Test Methods for Sheathed Thermocouples and
5. Materials and Manufacture
Sheathed Thermocouple Cable
5.1 All materials used shall be in accordance with the
E883 Guide for Reflected–Light Photomicrography
following requirements:
E1652 Specification for Magnesium Oxide and Aluminum
Oxide Powder and Crushable Insulators Used in the
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
Manufacture of Base Metal Thermocouples, Metal-
4th Floor, New York, NY 10036, http://www.ansi.org.
Sheathed Platinum Resistance Thermometers, and Noble
Available from American Welding Society (AWS), 550 NW LeJeune Rd.,
Metal Thermocouples Miami, FL 33126, http://www.aws.org.
E235/E235M−12 (2018)
TABLE 2 Tolerances on Initial Values of EMF versus Temperature for MIMS Thermocouples
NOTE 1—Tolerances in this table apply to new MIMS thermocouples.
NOTE 2—Tolerances apply to new material as produced and do not allow for changes in thermoelectric characteristics of the materials during use. The
magnitude of such changes depends upon such factors as sheath and thermoelement size, temperature, time of exposure, and the environment.
NOTE 3—Where tolerances are given in percent, the percentage applies to the temperature being measured when expressed in degrees Celsius.
NOTE 4—To determine the tolerance in degrees Fahrenheit, multiply the tolerance in degrees Celsius by 9/5.
Temperature Range Tolerances—Reference Junction 32°F [0°C]
Thermocouple
Standard Tolerances Special Tolerances
Type °F [°C]
°F [°C] °F [°C]
K or N 32 to 2300 [0 to 1260] Note 4 [The greater of ±2.2°C or ±0.75 %] Note 4 [The greater of ±1.1°C or ±0.4 %]
A B
K –328 to 32 [–200 to 0] [The greater of ±2.2°C or ±2 %]
A
MIMS the thermocouples are normally supplied to meet the tolerances specified in the table for temperatures above 0°C. The same materials, however, may not fall within
the sub-zero tolerances given in the second section of the table. If materials are required to meet the sub-zero limits, the purchase order shall so state. Selection of
materials shall be required.
B
Little information is available to justify establishing special tolerances for sub-zero temperatures. Such special sub-zero tolerances, if required, shall be agreed upon
between the purchaser and the producer.
5.1.1 Sheath Materials—The sheath material used for the 5.1.3.1 A certified analysis of the composition of the insu-
thermocouples described in this specification shall meet the lating material as supplied to the thermocouple manufacturer
requirements of Specification E585/E585M. The purchaser of shall be furnished to the purchaser. The thermocouple manu-
the thermocouples shall specify only the name of the material facturer shall be responsible for maintaining the purity in the
(seamless or welded), grade, optional requirements, test report finished product within the specified limits.
required, and ASTM designation. 5.1.4 Welding Rod—Filler rod material used for welding on
5.1.1.1 The inclusion level of the sheath shall be determined the sheath or for welding the end of the thermocouple closed
by mounting a 1-in. minimum length of a longitudinal section shall comply with the requirements ofAWS SpecificationA5.9
of the sheath using Test Methods E45, Microscopical Method for the sheath material specified on the ordering documents.
A, for examination. The inclusion level shall be less than 3 A
5.2 Processing:
through D, thin or heavy.
5.2.1 Cleanliness—The outer surface of the completed ther-
5.1.1.2 The grain size of the sheath shall be determined by
mocouples at the time of delivery shall be free of residues
aspecimentakeninaccordancewithTestMethodsE112.Grain
containing nuclear poisons (such as boron and cadmium
size shall be as specified in Table 3, or finer, as determined by
compounds) or foreign substances (such as chlorine
the Comparison Procedure of Test Methods E112.
compounds, strong acids or bases, oils, greases, or dust) that
5.1.1.3 Each lot of sheath material used shall be sampled
could become the source of corrosion or chemistry changes in
using Practices A262 as follows. Samples shall be tested by
a primary coolant or heat-transfer medium. The use of com-
Practice A, and further tested as outlined by Table 1 in
pounds containing halogens for final cleaning is prohibited.
Practices A262, where screening tests so indicate. Acceptance
Alcohol, or methyl isobutyl ketone may be used unless
levels for these tests shall be agreed upon between the
otherwise specified.
purchaser and the producer.
5.2.2 Annealing—The sheath of the finished thermocouple
5.1.2 Thermoelement—Thermoelements referred to in this
shall be solution annealed and shall not be sensitized.
specification shall be Type K or Type N with a standard
tolerance on initial values of emf versus temperature as
6. Inspection and Test Methods
specified in Table 2 unless otherwise specified by the pur-
6.1 General Procedure—Inspect and approve all thermo-
chaser.
couples in accordance with the sampling procedures specified
NOTE 1—The purchaser may specify an alternative type of thermoele-
in this section and with inspection requirements stated herein
ment as designated in Specification E230 by indicating this deviation in
and in referenced specifications. Acceptance of the sample
the ordering documents. The supplier and the purchaser shall then agree
inspection results does not relieve the thermocouple manufac-
upon a tolerance.
turer of the responsibility that all thermocouples shall conform
5.1.3 Insulation—The insulating material shall be either
to all requirements of this specification and the latest issue of
magnesia (MgO) or alumina (Al O ) and shall comply with
2 3
the referenced specifications.
Specification E1652 Type 1 material requirements:
6.1.1 Acceptance of thermocouples manufactured in accor-
dance with this specification requires the satisfactory comple-
TABLE 3 Maximum Grain Sizes
tion of the general tests specified for all thermocouples and
Sheath Outside Diameter, in. [mm] Maximum
three additional tests on selected sample thermocouples.
0.0400 [1.000] 6
6.1.2 Select one sample thermocouple at random from each
0.0625 [1.500] group of not more than 15 thermocouples from the same lot.
0.1250 [3.000]
Use sections of those sample thermocouples for the tests
0.1875 [4.500]
required in 6.7, 6.10.2, and 6.1.1. For the test in 6.10.2,
0.2500 [6.000]
fabricate a measuring junction of the same style as that in the
E235/E235M−12 (2018)
original group. Inspection and testing of this measuring rougher than 32 rms µin. Make a visual comparison with
junction, such as that in 6.3, is not required. roughness standards in accordance with ANSI B46.1.
6.2 Insulation Resistance—Measure the insulation resis- 6.6 Surface Defects—There shall be no cracks, seams,
holes, or other defects on the surface of the sheath of the
tance between the thermocouple circuit and the sheath of each
Style U thermocouple with a sheath length not exceeding 50 ft finished thermocouples when
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: E235/E235M − 12 E235/E235M − 12 (Reapproved 2018)
Standard Specification for
Type K and Type N Mineral-Insulated, Metal-Sheathed
Thermocouples for Nuclear or for Other High-Reliability
Applications
This standard is issued under the fixed designation E235/E235M; the number immediately following the designation indicates the year
of 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. Scope
1.1 This specification covers the requirements for simplex, compacted mineral-insulated, metal-sheathed (MIMS), Type K and
N thermocouples for nuclear or other high reliability service. Depending on size, these thermocouples are normally suitable for
operating temperatures to 1652°F [900°C]; special conditions of environment and life expectancy may permit their use at
temperatures in excess of 2012°F [1100°C]. This specification was prepared to detail requirements for this type of MIMS
thermocouple for use in nuclear environments, but they can also be used for laboratory or general commercial applications where
the environmental conditions exceed normal service requirements. The intended use of a MIMS thermocouple in a specific nuclear
application will require evaluation of the compatibility of the thermocouple, including the effect of the temperature, atmosphere,
and integrated neutron flux on the materials and accuracy of the thermoelements in the proposed application by the purchaser.
1.2 This specification does not attempt to include all possible specifications, standards, etc., for materials that may be used as
sheathing, insulation, and thermocouple wires for sheathed-type construction. The requirements of this specification include only
the austenitic stainless steels and other alloys as allowed by Specification E585/E585M for sheathing, magnesium oxide or
aluminum oxide as insulation, and Type K and N thermocouple wires for thermoelements (see Note 1).
1.3 General Design—Nominal sizes of the finished thermocouples shall be 0.0400 in., 0.0625 in., 0.125 in., 0.1875 in., or 0.250
in. [1.000 mm, 1.500 mm, 3.000 mm, 4.500 mm, or 6.000 mm]. Sheath dimensions and tolerances for each nominal size shall be
in accordance with Table 1 and Figs. 1 and 2. The measuring junction styles for thermocouples covered by this specification are
as follows:
1.3.1 Style G (grounded)—The measuring junction is electrically connected to its conductive sheath, and
1.3.2 Style U (ungrounded)—The measuring junction is electrically isolated from its conductive sheath and from reference
ground.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
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 all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
A262 Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels
This specification is under the jurisdiction of ASTM Committee E20 on Temperature Measurement and is the direct responsibility of Subcommittee E20.12 on
Thermocouples - Specifications.
Current edition approved May 1, 2012April 1, 2018. Published August 2012April 2018. Originally approved in 1964. Last previous edition approved in 20062012 as
E235 – 06.E235/E235M – 12. DOI: 10.1520/E0235-12.10.1520/E0235-12R18.
Style G and Style U measuring junctions were previously termed Class 1 and Class 2 measuring junctions respectively.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E235/E235M − 12 (2018)
TABLE 1 Dimensions for Style G and U Measuring Junctions
Sheath Outside Diameter, A Minimum Minimum Minimum E, Tolerance F, Tolerance
Sheath Insulation Wire
Tolerance
Wall, Thickness, Diameter,
Nominal min max min max
min max B C D
Inches
0.0400 0.0390 0.0415 0.006 0.004 0.005 0.006 0.020 0.004 0.021
0.0625 0.0615 0.0640 0.009 0.005 0.010 0.009 0.032 0.005 0.032
0.1250 0.1240 0.1265 0.012 0.012 0.020 0.012 0.062 0.012 0.063
0.1875 0.1865 0.1890 0.020 0.022 0.031 0.020 0.093 0.022 0.095
0.2500 0.2480 0.2520 0.030 0.024 0.040 0.030 0.125 0.024 0.125
[Millimetres]
[1.000] [0.975] [1.038] [0.15] [0.10] [0.13] [0.15] [0.51] [0.10] [0.53]
[1.500] [1.475] [1.538] [0.23] [0.13] [0.25] [0.23] [0.81] [0.13] [0.81]
[3.000] [2.975] [3.038] [0.30] [0.30] [0.51] [0.30] [1.57] [0.30] [1.60]
[4.500] [4.475] [4.538] [0.51] [0.56] [0.79] [0.51] [2.36] [0.56] [2.41]
[6.000] [5.950] [6.050] [0.76] [0.61] [1.02] [0.76] [3.18] [0.61] [3.18]
FIG. 1 Grounded Measuring Junction, Style G
FIG. 2 Ungrounded Measuring Junction, Style U
E3 Guide for Preparation of Metallographic Specimens
E45 Test Methods for Determining the Inclusion Content of Steel
E112 Test Methods for Determining Average Grain Size
E165 Practice for Liquid Penetrant Examination for General Industry
E220 Test Method for Calibration of Thermocouples By Comparison Techniques
E230 Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples
E344 Terminology Relating to Thermometry and Hydrometry
E585/E585M Specification for Compacted Mineral-Insulated, Metal-Sheathed, Base Metal Thermocouple Cable
E780 Test Method for Measuring the Insulation Resistance of Mineral-Insulated, Metal-Sheathed Thermocouples and
Mineral-Insulated, Metal-Sheathed Cable at Room Temperature
E839 Test Methods for Sheathed Thermocouples and Sheathed Thermocouple Cable
E883 Guide for Reflected–Light Photomicrography
E1652 Specification for Magnesium Oxide and Aluminum Oxide Powder and Crushable Insulators Used in the Manufacture of
Base Metal Thermocouples, Metal-Sheathed Platinum Resistance Thermometers, and Noble Metal Thermocouples
2.2 ANSI Standard:
B46.1 Surface Texture
2.3 American Welding Society Standard:
A5.9 Specification for Corrosion-Resisting Chromium and Chromium-Nickel Steel-Welding Rods and Bare Electrodes
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Available from American Welding Society (AWS), 550 NW LeJeune Rd., Miami, FL 33126, http://www.aws.org.
E235/E235M − 12 (2018)
3. Terminology
3.1 The definitions given in Terminology E344 shall apply to this specification.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 lot, n—a quantity of finished MIMS thermocouples manufactured from the same lot of MIMS cable, then assembled and
processed at the same time under the same controlled production conditions to their required final configuration.
4. Ordering Information and Basis of Purchase
4.1 The purchase order documents shall specify the following information:
4.1.1 The quantity, length, and nominal diameter of the MIMS thermocouple,
4.1.2 The thermocouple type and tolerance on the initial values of emf versus temperature per Table 2, if other than standard,
4.1.3 The type of ceramic insulation required, either alumina (Al O ) or magnesia (MgO),
2 3
4.1.4 The type of sheath material and other information required (see 5.1.1),
4.1.5 The style of thermocouple measuring junction (see 1.2),
4.1.6 The type of dye-penetrant inspection procedure to be used, and
4.1.7 Any deviations from this specification or the referenced specifications.
5. Materials and Manufacture
5.1 All materials used shall be in accordance with the following requirements:
5.1.1 Sheath Materials—The sheath material used for the thermocouples described in this specification shall meet the
requirements of Specification E585/E585M. The purchaser of the thermocouples shall specify only the name of the material
(seamless or welded), grade, optional requirements, test report required, and ASTM designation.
5.1.1.1 The inclusion level of the sheath shall be determined by mounting a 1-in. minimum length of a longitudinal section of
the sheath using Test Methods E45, Microscopical Method A, for examination. The inclusion level shall be less than 3 A through
D, thin or heavy.
5.1.1.2 The grain size of the sheath shall be determined by a specimen taken in accordance with Test Methods E112. Grain size
shall be as specified in Table 3, or finer, as determined by the Comparison Procedure of Test Methods E112.
5.1.1.3 Each lot of sheath material used shall be sampled using Practices A262 as follows. Samples shall be tested by Practice
A, and further tested as outlined by Table 1 in Practices A262, where screening tests so indicate. Acceptance levels for these tests
shall be agreed upon between the purchaser and the producer.
5.1.2 Thermoelement—Thermoelements referred to in this specification shall be Type K or Type N with a standard tolerance on
initial values of emf versus temperature as specified in Table 2 unless otherwise specified by the purchaser.
NOTE 1—The purchaser may specify an alternative type of thermoelement as designated in Specification E230 by indicating this deviation in the
ordering documents. The supplier and the purchaser shall then agree upon a tolerance.
5.1.3 Insulation—The insulating material shall be either magnesia (MgO) or alumina (Al O ) and shall comply with
2 3
Specification E1652 Type 1 material requirements:
5.1.3.1 A certified analysis of the composition of the insulating material as supplied to the thermocouple manufacturer shall be
furnished to the purchaser. The thermocouple manufacturer shall be responsible for maintaining the purity in the finished product
within the specified limits.
5.1.4 Welding Rod—Filler rod material used for welding on the sheath or for welding the end of the thermocouple closed shall
comply with the requirements of AWS Specification A5.9 for the sheath material specified on the ordering documents.
TABLE 2 Tolerances on Initial Values of EMF versus Temperature for MIMS Thermocouples
NOTE 1—Tolerances in this table apply to new MIMS thermocouples.
NOTE 2—Tolerances apply to new material as produced and do not allow for changes in thermoelectric characteristics of the materials during use. The
magnitude of such changes depends upon such factors as sheath and thermoelement size, temperature, time of exposure, and the environment.
NOTE 3—Where tolerances are given in percent, the percentage applies to the temperature being measured when expressed in degrees Celsius.
NOTE 4—To determine the tolerance in degrees Fahrenheit, multiply the tolerance in degrees Celsius by 9/5.
Temperature Range Tolerances—Reference Junction 32°F [0°C]
Thermocouple
Standard Tolerances Special Tolerances
Type °F [°C]
°F [°C] °F [°C]
K or N 32 to 2300 [0 to 1260] Note 4 [The greater of ±2.2°C or ±0.75 %] Note 4 [The greater of ±1.1°C or ±0.4 %]
A B
K –328 to 32 [–200 to 0] [The greater of ±2.2°C or ±2 %]
A
MIMS the thermocouples are normally supplied to meet the tolerances specified in the table for temperatures above 0°C. The same materials, however, may not fall within
the sub-zero tolerances given in the second section of the table. If materials are required to meet the sub-zero limits, the purchase order shall so state. Selection of
materials shall be required.
B
Little information is available to justify establishing special tolerances for sub-zero temperatures. Such special sub-zero tolerances, if required, shall be agreed upon
between the purchaser and the producer.
E235/E235M − 12 (2018)
TABLE 3 Maximum Grain Sizes
Sheath Outside Diameter, in. [mm] Maximum
0.0400 [1.000] 6
0.0625 [1.500]
0.1250 [3.000]
0.1875 [4.500]
0.2500 [6.000]
5.2 Processing:
5.2.1 Cleanliness—The outer surface of the completed thermocouples at the time of delivery shall be free of residues containing
nuclear poisons (such as boron and cadmium compounds) or foreign substances (such as chlorine compounds, strong acids or
bases, oils, greases, or dust) that could become the source of corrosion or chemistry changes in a primary coolant or heat-transfer
medium. The use of compounds containing halogens for final cleaning is prohibited. Alcohol, or methyl isobutyl ketone may be
used unless otherwise specified.
5.2.2 Annealing—The sheath of the finished thermocouple shall be solution annealed and shall not be sensitized.
6. Inspection and Test Methods
6.1 General Procedure—Inspect and approve all thermocouples in accordance with the sampling procedures specified in this
section and with inspection requirements stated herein and in referenced specifications. Acceptance of the sample inspection results
does not relieve the thermocouple manufacturer of the responsibility that all thermocouples shall conform to all requirements of
this specification and the latest issue of the referenced specifications.
6.1.1 Acceptance of thermocouples manufactured in accordance with this specification requires the satisfactory completion of
the general tests specified for all thermocouples and three additional tests on selected sample thermocouples.
6.1.2 Select one sample thermocouple at random from each group of not more than 15 thermocouples from the same lot. Use
sections of those sample thermocouples for the tests required in 6.7, 6.10.2, and 6.1.1. For the test in 6.10.2, fabricate a measuring
junction of the same style as that in the original group. Inspection and testing of this measuring junction, such as that in 6.3, is
not required.
6.2 Insulation Resistance—Measure the insulation resistance between the
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.