1、Designation: C202 93 (Reapproved 2013)Standard Test Method forThermal Conductivity of Refractory Brick1This standard is issued under the fixed designation C202; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. 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 test method to determinethe thermal cond
3、uctivity of refractory brick with the exceptionof insulating firebrick (use Test Method C182), and carbonrefractories. This test method is designed for refractorieshaving a conductivity factor of not more than 200 Btuin./hft2F (28.8 W/mK).1.2 UnitsThe values stated in inch-pound units are to beregar
4、ded as standard. The values given in parentheses aremathematical conversions to SI units that are provided forinformation only and are not considered standard.1.2.1 ExceptionCertain flow and weight measurementsare expressed in SI units only.1.3 This standard does not purport to address all of thesaf
5、ety 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 Insulati
6、ng FirebrickC182 Test Method for Thermal Conductivity of InsulatingFirebrickC201 Test Method for Thermal Conductivity of RefractoriesE220 Test Method for Calibration of Thermocouples ByComparison Techniques3. Significance and Use3.1 The thermal conductivity of refractory brick is a prop-erty require
7、d for selecting their thermal transmission charac-teristics. Users select refractory brick to provide specifiedconditions of heat loss and cold face temperature, withoutexceeding the temperature limitation of the brick. This testmethod establishes placement of thermocouples and position-ing of test
8、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 are suitable for specifi-cation acceptance, estimating heat loss and
9、surfacetemperature, and 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 consist of that described in TestMethod C201 with the addition of thermocouples, back-upinsul
10、ation, and refractory fiber paper as described in Sections 6and 7 of this test method.5. Test Specimens5.1 The test specimens shall be selected and prepared inaccordance with Test Method C201.6. Installation of Thermocouples in Test Specimen6.1 ThermocouplesCalibrated3thermocouples shall beembedded
11、in the test specimen at two points for measuringtemperature. Platinum-10 % rhodium/platinum thermocouplesshall be used. Wire of AWG Gage 28 (0.320 mm) shall be usedin making the thermocouples.6.2 Installation of Thermocouples The hot junction of thethermocouples shall be placed in the center of each
12、 9- by412-in. (228- by 114-mm) face and just below the surface of thetest specimen. Grooves to receive the wire shall be cut in each9- by 412-in. (228- by 114-mm) face of the brick to a depth of132 in. (0.8 mm) by means of an abrasive wheel 0.02 in. (0.5mm) in thickness. The layout for the grooves a
13、llows all of thecold junction ends of the wires to extend from one end of thebrick. A groove shall be cut in the center of each 9 by 412-in.(228- by 114-mm) face along the 412-in. (114-mm) dimensionand ending 1 in. (25.4 mm) from each edge. The path of each1This test method is under the jurisdiction
14、 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 1945. Last previous edition approved in 2009 as C202 93 (2009)1.DOI: 10.1520/C0202-93R13.2For ref
15、erenced 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.Copyr
16、ight ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1groove is extended at an angle of 90 to one end of the brickby cutting grooves parallel to and 1.0 in. (25.4 mm) from theedge of the specimen. Before cementing4the thermocouplewires in place,
17、 measurements shall be taken to obtain, within60.01 in. (0.3 mm), the eventual distance between the centerlines of the thermocouple junctions. This shall be done bymeasuring the 212-in. (64-mm) dimension of the brick at thelocation for the hot junctions and deducting the distancebetween the center l
18、ine of each junction in its embeddedposition and the surface of the brick.7. Set-Up of Back-Up Insulation, Specimen, and SiliconCarbide Slab7.1 The calorimeter and inner and outer guards shall becovered with a 0.50-in. (12.7-mm) thick layer of Group 20insulating firebrick (see Classification C155) f
19、or the purpose ofobtaining a higher mean temperature in the test specimen thanwould result by placing the specimen directly over the calo-rimeter area. The back-up insulation shall be cut and ground soas to provide surfaces that are plane and do not vary fromparallel by more than 60.01 in (0.3 mm).
20、The sides of thepieces that are to be placed in contact shall be ground plane andat right angles to the horizontal faces. The joints between thepieces shall be tight without the use of any mortar.7.2 Two strips of refractory fiber paper 1312 by12 by 0.02in. (343 by 13 by 0.5 mm) shall be placed alon
21、g the 1312-in.(343 mm) dimension of the inner guard at the outside edges.Twelve strips of refractory fiber paper 2 by12 by 0.02 in. (51by 13 by 0.5 mm) shall be placed on the outer guard at intervalsin the pattern shown in Fig. 1. These strips serve as spacers toprevent contact between the test mate
22、rial and the calorimeterassembly. The back-up insulation shall then be placed on thecalorimeter assembly so as to provide a level and plane surface.Additional strips of refractory fiber paper of the same dimen-sions shall be placed in the same pattern upon the back-upinsulation. These strips serve a
23、s spacers to prevent contactbetween the fireclay brick and the back-up insulation. The testspecimen shall be placed centrally over the center of thecalorimeter section on its 9- by 412-in. (228- by 114-mm) face,the guard brick placed at the sides of the test specimen so as tocover completely the cal
24、orimeter and inner guard area, and thesoap brick placed along the edges of the three brick so as tocover completely the calorimeter assembly. The small spacebetween the furnace walls and the test brick assembly shall befilled with granulated insulating firebrick.7.3 The silicon carbide slab shall be
25、 placed over the 1312-by 9-in. (343- by 228-mm) area of the three 9-in. (228 mm)4Alundum Cement RA 562 supplied by the Norton Co., One New Bond St.,Worcester, MA 01606, is satisfactory for this purpose.FIG. 1 Arrangement of Refractory Fiber Paper Strips in Calorimeter AssemblageC202 93 (2013)2brick
26、specimen, and it shall be spaced 1 in. (25.4 mm) abovethe specimen by placing under each corner of the slabrectangular pieces of Group 28 insulating firebrick cut tomeasure38-in. (10-mm) square and 1.00 in. (25.4 mm) inlength.8. Procedure8.1 Place the heating chamber in position, start waterflowing
27、through the calorimeter assembly, and supply currentto the heating unit. Above a temperature of 1470F (800C),the furnace atmosphere shall contain a minimum of 0.5 %oxygen with 0 % combustibles. Take the atmosphere samplefrom the furnace chamber proper, preferably as near the testspecimen as possible
28、. Maintain the rate of water flow throughthe calorimeter between 120 and 200 g/min, and determine itby weighing the quantity of water collected during a measuredtime period. The mass of water collected shall be not less than200 g and shall be weighed to an accuracy of 60.5 g. The rateof flow shall b
29、e constant within 6 1 % during the test period.8.2 Allow the furnace to reach a condition of steady state ofheat flow at a mean temperature of approximately 1400F(760C). A steady state shall be that condition when themeasured flow of heat into the calorimeter varies less than 2 %over a 2-h period, d
30、uring which time the temperature differencebetween the calorimeter and the inner guard has not been morethan 0.05F (0.03C), the hot face of the test specimen has notvaried more than 5F (3C), and the temperature of the waterentering the calorimeter has not varied at a rate of more than1F/h (0.5C/h) (
31、Note 1). Usually, 12 h or more are needed toobtain a balance with the apparatus after a definite change ismade in the hot-face temperature.NOTE 1Significant errors will result if the tolerances specified areexceeded.8.3 After the steady state of heat flow has been reached,measure the temperature of
32、the test specimen, the rate of waterflow through the calorimeter, and the temperature rise of thewater flowing through the calorimeter. Take at least four sets ofreadings (Note 2) at approximately 30-min intervals during the2-h holding period, and average these for the final values forthat particula
33、r heating chamber temperature. Calculate thethermal conductivity.NOTE 2From these data a preliminary thermal conductivity calcula-tion may be made, using estimated distances between thermocouplejunctions in the test specimen.8.4 Reheating treatment of the test specimen at a hightemperature is necess
34、ary to eliminate errors arising frompermanent changes in the sample which would affect thethermal conductivity value (Note 3). Carry out reheating, afterobtaining the conductivity of the test specimen at the meantemperature of 1400F (760C) (8.2 and 8.3), by raising thetemperature in the heating cham
35、ber to the highest value (Note4) to be used in testing the sample, and maintaining thattemperature for 18 6 2 h. Although water is circulated throughthe calorimeter assembly during this period, no heat flowreadings need be taken. After this interval, reduce the tempera-ture in the heating chamber to
36、 obtain a mean temperature ofapproximately 1400F (760C) in the specimen. After steadystate has been reached at this temperature, take heat flowmeasurements, as previously outlined, and calculate the con-ductivity. Provided the conductivity value obtained at the lowermean temperature 1400F (760C) doe
37、s not check that fromthe reheating operation to within 62 %, repeat the reheatingoperation and the low-temperature trial until check data areobtained.NOTE 3Significant variation in thermal conductivity upon further heattreatment will be observed if the reheating treatment specified is ne-glected.NOT
38、E 4The temperature to which the sample is heated depends uponthe properties of the material. Changes in volume and structure resultingfrom high-temperature treatment may alter the conductivity value of theproduct.8.5 After the specimen has been stabilized (8.4), make atleast three additional conduct
39、ivity determinations (Note 5),using heating chamber temperatures between the maximumand minimum used in bringing about the stable condition.NOTE 5When it is necessary or desirable to obtain data at meantemperatures below 1400F (760C), the 0.50-in. (12.7-mm) layer ofback-up insulation should be remov
40、ed so as to provide greater heat flowbetween the test material and the calorimeter.8.6 At the conclusion of the test, examine the specimens forchanges that may have taken place as a result of the heattreatment. Then remove the thermocouple wires and cut thebrick in half through the 412-by212-in. (11
41、4- by 64-mm)dimension and examine for voids and cracks.9. Record of Test Data, Calculations, and Report9.1 Make the record of test data, the calculations, and thereport in accordance with Test Method C201.10. Precision and Bias10.1 Refer to Test Method C201 for a statement of precisionand bias.11. K
42、eywords11.1 calorimeter; refractories; refractory brick; thermal con-ductivityC202 93 (2013)3ASTM 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 determinati
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