1、Designation: C 202 93 (Reapproved 2004)Standard Test Method forThermal Conductivity of Refractory Brick1This standard is issued under the fixed designation C 202; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number 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 test method supplements Test Method C 201 andshall be used in conjunction with that test method to determinethe thermal
3、conductivity of refractory brick with the exceptionof insulating firebrick (use Test Method C 182), 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 The values stated in inch-pound units are to be rega
4、rdedas the standard. The values in parentheses are provided forinformation only.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 det
5、ermine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 155 Classification of Insulating FirebrickC 182 Test Method for Thermal Conductivity of InsulatingFirebrickC 201 Test Method for Thermal Conductivity of Refracto-riesE 220 Method for Calibra
6、tion of Thermocouples by Com-parison Techniques3. Significance and Use3.1 The thermal conductivity of refractory brick is a prop-erty required for selecting their thermal transmission charac-teristics. Users select refractory brick to provide specifiedconditions of heat loss and cold face temperatur
7、e, withoutexceeding the temperature limitation of the brick. This testmethod establishes placement of thermocouples and position-ing of test specimens in the calorimeter.3.2 This procedure must be used with Test Method C 201and requires a large thermal gradient and steady state condi-tions. The resu
8、lts are based upon a mean temperature.3.3 The data from this test method are suitable for specifi-cation acceptance, estimating heat loss and surface tempera-ture, and design of multi-layer refractory construction.3.4 The use of these data requires consideration of the actualapplication environment
9、and conditions.4. Apparatus4.1 The apparatus shall consist of that described in TestMethod C 201 with the addition of thermocouples, back-upinsulation, 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 prepare
10、d inaccordance with Test Method C 201.6. Installation of Thermocouples in Test Specimen6.1 ThermocouplesCalibrated3thermocouples shall beembedded in the test specimen at two points for measuringtemperature. Platinum-10 % rhodium/platinum thermocouplesshall be used. Wire of AWG Gage 28 (0.320 mm) sha
11、ll be usedin making the thermocouples.6.2 Installation of Thermocouples The hot junction of thethermocouples shall be placed in the center of each 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. face of
12、the brick to a depth of132 in. (0.8 mm) bymeans of an abrasive wheel 0.02 in. (0.5 mm) in thickness. Thelayout for the grooves allows all of the cold junction ends ofthe wires to extend from one end of the brick. A groove shallbe cut in the center of each 9 by 412-in. face along the 412-in.dimension
13、 and ending 1 in. (25 mm) from each edge. The pathof each groove is extended at an angle of 90 to one end of thebrick by cutting grooves parallel to and 1.0 in. from the edgeof the specimen. Before cementing4the thermocouple wires inplace, measurements shall be taken to obtain, within 60.01 in.(0.3
14、mm), the eventual distance between the center lines of the1This test method is under the jurisdiction of ASTM Committee C08 onRefractories and is the direct responsibility of Subcommittee C08.02 on ThermalStress Resistance.Current edition approved Sept. 1, 2004. Published October 2004. Originallyapp
15、roved in 1945. Last previous edition approved in 1998 as C 202 93 (19938).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
16、ASTM website.3Method E 220 specifies calibration procedures for thermocouples.4Alundum Cement RA 562 supplied by the Norton Co., One New Bond St.,Worcester, MA 01606, is satisfactory for this purpose.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
17、 United States.thermocouple junctions. This shall be done by measuring the212-in. (64-mm) dimension of the brick at the location for thehot junctions and deducting the distance between the centerline of each junction in its embedded position and the surfaceof the brick.7. Set-Up of Back-Up Insulatio
18、n, 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 C 155) for the purposeof obtaining a higher mean temperature in the test specimenthan would result by placing t
19、he specimen directly over thecalorimeter area. The back-up insulation shall be cut andground so as to provide surfaces that are plane and do not varyfrom parallel by more than 60.01 in (0.3 mm). The sides of thepieces that are to be placed in contact shall be ground plane andat right angles to the h
20、orizontal 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. (342 by 13 by 0.5 mm) shall be placed along the 1312-in.dimension of the inner guard at the outside edges. Twelve stripsof refractory fiber paper 2
21、 by12 by 0.02 in. (51 by 13 by 0.5mm) shall be placed on the outer guard at intervals in thepattern shown in Fig. 1. These strips serve as spacers to preventcontact between the test material and the calorimeter assembly.The back-up insulation shall then be placed on the calorimeterassembly so as to
22、provide a level and plane surface. Additionalstrips of refractory fiber paper of the same dimensions shall beplaced in the same pattern upon the back-up insulation. Thesestrips serve as spacers to prevent contact between the fireclaybrick and the back-up insulation. The test specimen shall beplaced
23、centrally over the center of the calorimeter section on its9- by 412-in. (228- by 114-mm) face, the guard brick placed atthe sides of the test specimen so as to cover completely thecalorimeter and inner guard area, and the soap brick placedalong the edges of the three brick so as to cover completely
24、 thecalorimeter assembly. The small space between the furnacewalls and the test brick assembly shall be filled with granulatedinsulating firebrick.7.3 The silicon carbide slab shall be placed over the 1312-by 9-in. (342- by 228-mm) area of the three 9-in. brickspecimen, and it shall be spaced 1 in.
25、(25 mm) above thespecimen by placing under each corner of the slab rectangularpieces of Group 28 insulating firebrick cut to measure38-in.(10-mm) square and 1.00 in. (25.4 mm) in length.8. Procedure8.1 Place the heating chamber in position, start waterflowing through the calorimeter assembly, and su
26、pply 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. Maintain the rate of water flow throug
27、hthe 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 thanFIG. 1 Arrangement of Refractory Fiber Paper Strips in Calorimeter AssemblageC 202 93 (2004)2200 g and shall be weig
28、hed to an accuracy of 60.5 g. The rateof flow shall be 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
29、 calorimeter varies less than 2 %over a 2-h period, during 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
30、 has not varied at a rate of more than1F/h (0.5C/h) (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 h
31、eat flow has been reached,measure the temperature of 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
32、 average these for the final values forthat particular 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 treatmen
33、t of the test specimen at a hightemperature is necessary 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 an
34、d 8.3), by raising thetemperature in the heating chamber 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 interv
35、al, reduce the tempera-ture in the heating chamber to obtain a mean temperature ofapproximately 1400F in the specimen. After steady state hasbeen reached at this temperature, take heat flow measurements,as previously outlined, and calculate the conductivity. Providedthe conductivity value obtained a
36、t the lower mean temperature(1400F) does not check that from the reheating operation towithin 62 %, repeat the reheating operation and the low-temperature trial until check data are obtained.NOTE 3Significant variation in thermal conductivity upon further heattreatment will be observed if the reheat
37、ing treatment specified is ne-glected.NOTE 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.
38、4), make atleast three additional conductivity 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) l
39、ayer ofback-up insulation should be removed 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 thebr
40、ick in half through the 412-by212-in. (114- 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 C 201.10. Precision and Bias10.1 Refer to Text Method C 201
41、 for a statement ofprecision and bias.11. Keywords11.1 calorimeter; refractories; refractory brick; thermalconductivityASTM 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 expressl
42、y advised that determination 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, e
43、ither reapproved or 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 atte
44、nd. If you feel that 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 (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).C 202 93 (2004)3
