1、Designation: C 865 02 (Reapproved 2007)Standard Practice forFiring Refractory Concrete Specimens1This standard is issued under the fixed designation C 865; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This practice covers the firing of specimens made f
3、romrefractory concretes (castable refractories) in accordance withPractice C 862 for cast specimens. The procedure is alsorecommended for heating rates to be used for high-temperaturetest methods such as Methods C 16, C 583, etc., when thesemethods are used to test refractory concretes.1.2 The value
4、s stated in inch-pound units are to be regardedas the standard. The values given in parentheses are 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-pr
5、iate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C16 Test Method for Load Testing Refractory Shapes atHigh TemperaturesC20 Test Methods for Apparent Porosity, Water Absorp-tion, Apparent Specific Gravi
6、ty, and Bulk Density ofBurned Refractory Brick and Shapes by Boiling WaterC113 Test Method for Reheat Change of Refractory BrickC 133 Test Methods for Cold Crushing Strength and Modu-lus of Rupture of RefractoriesC 210 Test Method for Reheat Change of Insulating Fire-brickC 288 Test Method for Disin
7、tegration of Refractories in anAtmosphere of Carbon MonoxideC 401 Classification of Alumina and Alumina-SilicateCastable RefractoriesC 546 Method of Load Testing Refractory Brick at HighTemperatures, Long Time3C 583 Test Method for Modulus of Rupture of RefractoryMaterials at Elevated TemperaturesC
8、704 Test Method for Abrasion Resistance of RefractoryMaterials at Room TemperatureC 832 Test Method of Measuring Thermal Expansion andCreep of Refractories Under LoadC 862 Practice for Preparing Refractory Concrete Speci-mens by CastingE 220 Test Method for Calibration of Thermocouples ByComparison
9、Techniques3. Significance and Use3.1 This practice is used to standardize the firing conditionsof refractory concrete specimens prepared in accordance withPractice C 862. The standards are set down to minimizelaboratory-to-laboratory variation and do not attempt to dupli-cate any particular field ap
10、plications.4. Apparatus4.1 Kiln, equipped with instruments capable of controllingthe heating rate of the kiln at 100 to 700F (55 to 380C)/h (see6.5) and holding the soak temperature to 610F (5.5C) of thenominal soak temperature. For temperatures up to 2500F(1370C) an electrically heated kiln is pref
11、erred, but gas- oroil-fired kilns can be used for all temperatures, provided theheating rates specified can be maintained, the flame of theburners does not impinge directly on any specimen, and thefurnace atmosphere contains a minimum of 0.5 % oxygen with0 % combustibles.4.2 BalancesFor9by412 by 2 o
12、r 3-in. (228 by 114 by 51or 76-mm) samples, a balance with a capacity of 15 lb (6.8 kg)and a sensitivity of 0.01 lb (4.5 g) is recommended; for smallerspecimens (for example, 6 by 1 by 1-in. (152 by 25 by 25-mm)bars), a 2-kg balance with a sensitivity of 0.1 g is recom-mended.4.3 Caliper or Steel Ru
13、le, to measure the dimensions of thespecimens. For large specimens, a 12-in. (305-mm) steel rulewith 0.01-in. (0.3-mm) divisions is recommended. For smaller1This practice is under the jurisdiction ofASTM Committee C08 on Refractoriesand is the direct responsibility of Subcommittee C08.09 on Monolith
14、ics.Current edition approved Oct. 1, 2007. Published November 2007. Originallyapproved in 1977. Last previous edition approved in 2002 as C 865 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandard
15、s volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.specimens, a 250-mm caliper with 0.1-mm divisions is recom-mended. Other measuring device
16、s of the same or betterprecision may also be used.5. Preparation of Samples5.1 Samples are prepared by casting in accordance withMethods C 862. If the sample size of the cast specimen is thesame as that specified for the test, it can be used directly.However, cutting samples of the required size fro
17、m larger castblocks will often be necessary (Note 1). In this case, it isrecommended that the samples be cut with a diamond saw.After cutting, the samples should be dried at 230F (110C) fora minimum of 18 h. All cut samples should have sharp edgesand corners and should not show pull-out of grains on
18、 the cutsurfaces. For some low-strength castables, drying prior tocutting may be needed to increase their strength and resistanceto pull-outs.NOTE 1Specimens cut from the interior of large cement bondedcastables shapes may be stronger than specimens cut from small castshapes because the interior of
19、large cast shapes are exposed to highpressure steam during dryout which causes more complete hydration ofthe cement.5.2 Some types of castables, especially those containingaggregates of a relatively low hardness (such as lightweightcastables), may be cut on a dry saw. This procedure isacceptable pro
20、vided that specimens with sharp corners andedges, which show no signs of grain pull-out at the cutsurfaces, are obtained.6. Procedure6.1 Label all specimens with ceramic ink or ceramic cray-ons.6.2 Measure all dimensions of the specimens using a steelrule or caliper. Make the measurement at the cent
21、er of eachside and to the nearest 0.01 in. (0.3 mm) or 0.1 mm, dependingon the instrument used and the sample size. When using anindentation mark in accordance with 7.3 in Practice C 862,remeasure the distance between the reference marks to deter-mine the total linear change from the as-cast state (
22、Note 2).6.3 Measure the weight of the specimens to the nearest 0.01lb (4.5 g) for samples weighing approximately 4 lb (1.8 kg) ormore, or to the nearest 0.0002 lb (0.1 g) for samples weighingless than 4 lb.NOTE 2Linear change measurements based on the initial cast speci-men cannot be determined when
23、 specimens are cut from larger sections.6.4 Place the specimens in the kiln so that each specimenwill rest on the surface formed by its longest and smallestdimension (that is, the 9 by 212-in. (230 by 65-mm) surface for9-in. straight, or the 6 by 1-in. (152 by 25-mm) surface for 6 by1 by 1 in. sampl
24、es). Support each specimen on a flat supportingbrick, which does not soften or shrink at the intended soaktemperature. Place between the test specimens and the support-ing brick a layer of suitable refractory material that is nonre-active under the test conditions and passes a No. 16 (1.18-mm)sieve
25、and is retained on a No. 40 (425-m) sieve.NOTE 3Specimens tested for refractoriness under load or creep mustbe placed in a furnace as indicated in Methods C 16 and C 546,respectively.6.5 The following maximum heating rates at temperaturesbelow 1500F (815C) are recommended:Cross Section of SpecimenMa
26、ximum HeatingRatein. mm F/h C/h41/2by3 114by76 100 5541/2by21/2 114 by 65 100 552 by 2 228 by 64 300 1701 by 1 25 by 25 700 380At temperatures over 1500F a heating rate up to 700F(390C)/h is permissible. Generally, a slower heating rate doesnot affect the properties of the specimens adversely. Thus,
27、when smaller and larger specimens are fired together, theheating rate applicable to the larger specimens should be used.NOTE 4Different heating rates are specified for various samples toensure that the difference in temperature between the center and thesurface of the specimen does not exceed 45F (2
28、5C). Experimentalevidence indicates that cracking may occur when a castable sample isheated too rapidly. The safe heat-up rate increases with decreasing samplesize.6.6 Hold the specimens at the specified temperature for 5 h.During the holding period a furnace atmosphere containing aminimum of 0.5 %
29、oxygen with 0 % combustibles should bemaintained. For special high-temperature tests a longer orshorter holding time may be required, that is, 112 h for therefractoriness-under-load test (Method C16), or 12 h for thehot modulus of rupture test (Test Method C 583).6.7 Measure the temperature within t
30、he kiln by means of aplatinum-rhodium/platinum type thermocouple, calibrated inaccordance with Method E 220, and a potentiometer, prefer-ably of the recording type for temperatures up to 2700F(1480C). For temperatures in the 2700 to 3100F (1480 to1705C) range, either a platinum-rhodium/platinum or a
31、 plati-num 6 % rhodium-platinum 30 % rhodium (Type B) thermo-couple can be used. For temperatures over 3100F, a Type Bthermocouple must be used. The hot junction of the thermo-couple should be placed in close proximity to the specimens.An alternative method is the use of a calibrated opticalpyromete
32、r where applicable. Make temperature readings atintervals of 15 min or less when the temperature is not recordedand controlled automatically. The use of cone plaques isadvised as a guide to temperature uniformity within the kiln.6.8 After completion of the firing, cool the specimens in aclosed kiln
33、at a cooling rate not exceeding 500F (280C)/h.6.9 Within 2 h after the fired specimens reach room tem-perature, remeasure their dimensions and weight in accordancewith 6.2 and 6.3 if density change or dimensional change, orboth, data are required. Adhering loose setting materials andsmall blisters m
34、ust be removed prior to such measurement.6.10 When room temperature strength measurements (TestMethods C 133) are to be made after firing, store the firedspecimens in a desiccator, or alternatively in a drying oven heldat 230F (110C), to prevent moisture pick up from the airprior to testing. Strengt
35、h measurements should be made within2 h after removal from the desiccator or drying oven.NOTE 5Refractory concrete specimens exposed to room air afterfiring have shown strength changes as exposure time in room air increaseswhen tested in accordance with Test Methods C 133 or other strength testmetho
36、ds.C 865 02 (2007)27. Use of Recommended Firing Practices7.1 Refractory concrete specimens required for themethods listed in 7.1.1 through 7.1.6 should be fired inaccordance with this practice. If the specimens are tested attemperature, the firing procedures described in this practiceshould be used
37、to heat the specimens to the required testtemperature and to cool them after the test is completed (thelatter is necessary only if subsequent measurements are madeat room temperature). The most frequently used tests are:7.1.1 Methods C 16 and C 546In these methods, theheat-up schedule should follow
38、the procedure described in thispractice.7.1.2 Test Methods C 20Holding temperature(s) as re-quired for the intended service temperature.7.1.3 Test Methods C 113 and C 210The procedures de-scribed in these practices include all measurements needed tocalculate the linear and, optionally, the volume ch
39、ange ofcastables from the dried state only. The total linear change fromthe as-cast specimens are calculated by either using thedistances between the reference marks measured as-cast andafter drying or firing or both, or by using the caliperedlongitudinal inside mold dimension as the initial specime
40、n sizeor zero point. Holding temperatures appropriate for the ASTMclassification of castables (Classification C 401) or for theintended service temperature may be selected.7.1.4 Test Methods C 133 and C 583Holding tempera-ture(s) for determining cold crushing strength and modulus ofrupture are as re
41、quired for the intended purpose (servicetemperatures) or as specified by the consumer, usually 1500 to2000F (815 to 1095C).7.1.5 Test Method C 288Carbon monoxide disintegrationis determined at holding temperatures of 1000 and 2000F (540and 1095C).7.1.6 Test Method C 704Holding temperature(s) forspec
42、imens to be tested for abrasion resistance at room tem-perature are as required for the intended purpose or as specifiedby the purchaser.8. Keywords8.1 castables; elevated temperatures; linear change; refrac-tory concreteASTM International takes no position respecting the validity of any patent righ
43、ts asserted in connection with any item mentionedin this standard. Users of this standard are expressly 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
44、time by the responsible technical committee and must be reviewed every five years andif not revised, either 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 wil
45、l receive careful consideration at a meeting of theresponsible technical committee, which you may attend. 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 AST
46、M 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 865 02 (2007)3
