ASTM C767-93(2004)
(Test Method)Standard Test Method for Thermal Conductivity of Carbon Refractories
Standard Test Method for Thermal Conductivity of Carbon Refractories
SIGNIFICANCE AND USE
The thermal conductivity of carbon refractories is a property required for selecting their thermal transmission characteristics. Users select carbon refractories to provide specified conditions of heat loss and cold face temperature, without exceeding the temperature limitation of the carbon refractory. This test method establishes placement of thermocouples and positioning of test specimens in the calorimeter.
This procedure must be used with Test Method C 201 and requires a large thermal gradient and steady state conditions. The results are based upon a mean temperature.
The data from this test method is suitable for specification acceptance, estimating heat loss and surface temperature, and the design of multi-layer refractory construction.
The use of these data requires consideration of the actual application environment and conditions.
SCOPE
1.1 This test method supplements Test Method C 201, and shall be used in conjunction with that procedure to determine the thermal conductivity of carbon or carbon-bearing refractories. This test method is designed for refractories having a conductivity factor of not more than 200 Btuin./hft2F (28.8 W/mK).
1.2 The values stated in inch-pound units are to be regarded as the standard.
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:C 767–93 (Reapproved 2004)
Standard Test Method for
Thermal Conductivity of Carbon Refractories
This standard is issued under the fixed designation C 767; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.3 The data from this test method is suitable for specifica-
tion acceptance, estimating heat loss and surface temperature,
1.1 This test method supplements Test Method C 201, and
and the design of multi-layer refractory construction.
shall be used in conjunction with that procedure to determine
3.4 Theuseofthesedatarequiresconsiderationoftheactual
the thermal conductivity of carbon or carbon-bearing refracto-
application environment and conditions.
ries. This test method is designed for refractories having a
conductivity factor of not more than 200 Btu·in./h·ft ·°F (28.8
4. Apparatus
W/m·K).
4.1 The apparatus shall be in accordance with Test Method
1.2 The values stated in inch-pound units are to be regarded
C 201 with the addition of thermocouples, back-up insulation,
as the standard.
and refractory fiber paper as described in Section 5 of this test
1.3 This standard does not purport to address all of the
method.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Test Specimen and Preparation
priate safety and health practices and determine the applica-
5.1 Select the test specimen and prepare in accordance with
bility of regulatory limitations prior to use.
Test Method C 201.
5.2 Thermocouples—Embed calibrated thermocouples in
2. Referenced Documents
the test specimen at two points for measuring temperature.
2.1 ASTM Standards:
Thermocouples sheathed with material having low reactivity
C 155 Classification of Insulating Firebrick
with carbon must be used. Use the top thermocouple for one
C 201 Test Method for Thermal Conductivity of Refracto-
test only.
ries
5.3 Installation of Thermocouples— Place the hot junction
E 220 Method for Calibration of Thermocouples by Com-
of the thermocouples in the center of each 9 by 4 ⁄2-in. (228 by
parison Techniques
114-mm) face and just below the surface of the test specimen.
3. Significance and Use Cut grooves to receive the wire in each 9 by 4 ⁄2-in. face of the
brick to a depth necessary to embed the thermocouple just
3.1 The thermal conductivity of carbon refractories is a
beneath the surface by means of an abrasive wheel. The layout
property required for selecting their thermal transmission
for the grooves allows all of the cold-junction ends of the wires
characteristics. Users select carbon refractories to provide
to extend from one end of the brick. Cut a groove in the center
specified conditions of heat loss and cold face temperature,
1 1
of each 9 by 4 ⁄2-in. face along the 9-in. dimension and end ⁄4
without exceeding the temperature limitation of the carbon
in. (6 mm) beyond the center. Before cementing the thermo-
refractory. This test method establishes placement of thermo-
couples in place, take measurements to obtain, within 60.01
couples and positioning of test specimens in the calorimeter.
in. (60.3 mm), the eventual distance between the center lines
3.2 This procedure must be used with Test Method C 201
of the thermocouple junctions. Do this by measuring the
and requires a large thermal gradient and steady state condi-
2 ⁄2-in. (64-mm) dimension of the brick at the location for the
tions. The results are based upon a mean temperature.
hot junctions and deducting the distance between the center
line of each junction in its embedded position and the surface
This test method is under the jurisdiction of ASTM Committee C08 on
of the brick.
Refractories and is the direct responsibility of Subcommittee C08.02 on Thermal
Properties.
Current edition approved Sept. 1, 2004. Published October 2004. Originally
approved in 1973. Last previous edition approved in 1998 as C 767 – 93 (1998). Method E 220 specifies calibration procedures for thermocouples.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Claud S. Gordon Co., 5710 Kenosha St., Richmond, IL 60071, 1 16 -in.
/
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM (2-mm) sheathed Xactpak thermocouple, Cat. No. 401-2104 or equivalent.
Standards volume information, refer to the standard’s Document Summary page on Alundum Cement RA 562 supplied by the Norton Co., One New Bond St.,
the ASTM website. Worcester, MA 01606, is satisfactory for this purpose.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 767–93 (2004)
5.4 Cover the calorimeter and inner and outer guards with a 6. Conditions of Test
0.50-in. (12.7-mm) thick layer of Group 20 insulating firebrick
6.1 Make a special effort to seal the furnace tightly so that
(see Classification C 155) for the purpose of obtaining a higher
the atmosphere can be maintained nonoxidizing through intro-
mean temperature in the test sample than would result by
duction of argon under slight positive pressure as measured by
placing the sample directly over the calorimeter area. Cut and
a draft gage. In addition, place several pieces of carbon
grind the back-up insulation so as to provide surfaces that are
refractory around the edges of the furnace on top of the outer
plane and do not vary from parallel by more than 60.01 in.
guardbricktoreactwithanyoxygenthatmayenterthe
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