ASTM_C_767_-_93_2013.pdf

Designation:C76793(Reapproved 2013)Standard Test Method forThermal Conductivity of Carbon Refractories1This standard is issued under the fixed designation C767;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method supplements Test Method C201,andshall be used in conjunction with that procedure to determinethe thermal conductivity of carbon or carbon-bearing refracto-ries.This test method is designed for refractories having aconductivity factor of not more than 200 Btuin./hft2F(28.8W/mK).1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns,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:2C155 Classification of Insulating FirebrickC201 Test Method for Thermal Conductivity of RefractoriesE220 Test Method for Calibration of Thermocouples ByComparison Techniques3.Significance and Use3.1 The thermal conductivity of carbon refractories is aproperty required for selecting their thermal transmissioncharacteristics.Users select carbon refractories to providespecified conditions of heat loss and cold face temperature,without exceeding the temperature limitation of the carbonrefractory.This test method establishes placement of thermo-couples and positioning of test specimens in the calorimeter.3.2 This procedure must be used with Test Method C201and requires a large thermal gradient and steady state condi-tions.The results are based upon a mean temperature.3.3 The data from this test method is suitable for specifica-tion acceptance,estimating heat loss and surface temperature,and the design of multi-layer refractory construction.3.4 The use of these data requires consideration of the actualapplication environment and conditions.4.Apparatus4.1 The apparatus shall be in accordance with Test MethodC201 with the addition of thermocouples,back-up insulation,and refractory fiber paper as described in Section 5 of this testmethod.5.Test Specimen and Preparation5.1 Select the test specimen and prepare in accordance withTest Method C201.5.2 ThermocouplesEmbed calibrated thermocouples3inthe test specimen at two points for measuring temperature.Thermocouples4sheathed with material having low reactivitywith carbon must be used.Use the top thermocouple for onetest only.5.3 Installation of ThermocouplesPlace the hot junctionof the thermocouples in the center of each 9 by 412-in.(228 by114-mm)face and just below the surface of the test specimen.Cut grooves to receive the wire in each 9 by 412-in.face of thebrick to a depth necessary to embed the thermocouple justbeneath the surface by means of an abrasive wheel.The layoutfor the grooves allows all of the cold-junction ends of the wiresto extend from one end of the brick.Cut a groove in the centerof each 9 by 412-in.face along the 9-in.dimension and end14in.(6 mm)beyond the center.Before cementing5the thermo-couples in place,take measurements to obtain,within 60.01in.(60.3 mm),the eventual distance between the center linesof the thermocouple junctions.Do this by measuring the212-in.(64-mm)dimension of the brick at the location for the1This test method is under the jurisdiction of ASTM Committee C08 onRefractories and is the direct responsibility of Subcommittee C08.02 on ThermalProperties.Current edition approved Sept.1,2013.Published September 2013.Originallyapproved in 1973.Last previous edition approved in 2009 as C767 93(2009).DOI:10.1520/C0767-93R13.2For 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.3Method E220 specifies calibration procedures for thermocouples.4Claud S.Gordon Co.,5710 Kenosha St.,Richmond,IL 60071,116in.(2mm)sheathed Xactpak thermocouple,Cat.No.401-2104 or equivalent.5Alundum Cement RA 562 supplied by the Norton Co.,One New Bond St.,Worcester,MA 01606,is satisfactory for this purpose.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 hot junctions and deducting the distance between the centerline of each junction in its embedded position and the surfaceof the brick.5.4 Cover the calorimeter and inner and outer guards with a0.50-in.(12.7-mm)thick layer of Group 20 insulating firebrick(see Classification C155)for the purpose of obtainin