1、Designation: C865 17Standard Practice forFiring Refractory Concrete Specimens1This standard is issued under the fixed designation C865; 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 parenthe
2、ses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This practice covers the firing of specimens made fromrefractory co
3、ncretes (castable refractories) in accordance withPractice C862 for cast specimens. The procedure is alsorecommended for heating rates to be used for high-temperaturetest methods such as Test Methods C16, C583, etc., when thesemethods are used to test refractory concretes.1.2 The values stated in in
4、ch-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-priate safety, h
5、ealth, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of Inter
6、national Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C16 Test Method for Load Testing Refractory Shapes atHigh TemperaturesC583 Test Method for Modulus of Rupture of RefractoryMate
7、rials at Elevated TemperaturesC862 Practice for Preparing Refractory Concrete Specimensby CastingE230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized Thermocouples3. Significance and Use3.1 This practice is used to standardize the firing conditionsof refractory concret
8、e specimens prepared in accordance withPractice C862. The standards are set down to minimizelaboratory-to-laboratory variation and do not attempt to dupli-cate any particular field applications.4. Apparatus4.1 Kiln, equipped with instruments capable of controllingthe heating rate of the kiln at 100
9、to 700 F (55 to 380 C) h(see 6.5) and holding the soak temperature to 610 F (5.5 C)of the nominal soak temperature. For temperatures up to2500 F (1370 C) an electrically heated kiln is preferred, butgas- or oil-fired kilns can be used for all temperatures, providedthe heating rates specified can be
10、maintained, the flame of theburners does not impinge directly on any specimen, and thefurnace atmosphere contains a minimum of 0.5 % oxygen with0 % combustibles.5. Preparation of Samples5.1 Samples are prepared by casting in accordance withPractice C862. If the sample size of the cast specimen is th
11、esame as that specified for the test, it can be used directly.However, cutting samples of the required size from 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 230 F (110 C)fo
12、r a minimum of 18 h. All cut samples should have sharpedges and corners and should not show pull-out of grains onthe cut surfaces. For some low-strength castables, drying priorto cutting may be needed to increase their strength andresistance to pull-outs.NOTE 1Specimens cut from the interior of larg
13、e cement-bondedcastables shapes may be stronger than specimens cut from small castshapes because the interior of large cast shapes are exposed to high-pressure steam during dryout which causes more complete hydration ofthe cement.5.2 Some types of castables, especially those containingaggregates of
14、a relatively low hardness (such as lightweightcastables), may be cut on a dry saw. This procedure isacceptable provided that specimens with sharp corners andedges, which show no signs of grain pull-out at the cutsurfaces, are obtained.1This practice is under the jurisdiction ofASTM Committee C08 on
15、Refractoriesand is the direct responsibility of Subcommittee C08.09 on Monolithics.Current edition approved Nov. 1, 2017. Published November 2017. Originallyapproved in 1977. Last previous edition approved in 2013 as C865 13. DOI:10.1520/C0865-17.2For referenced ASTM standards, visit the ASTM websit
16、e, 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesT
17、his international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade
18、(TBT) Committee.1Mon Apr 30 54 6. Procedure6.1 Label all specimens with ceramic ink or ceramic cray-ons.6.2 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 64-mm) surface for9-in. straight, o
19、r the 6 by 1-in. (152 by 25-mm) surface for 6 by1 by 1-in. samples). 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-acti
20、ve under the test conditions and passes a No. 16 (1.18-mm)sieve and is retained on a No. 40 (425-m) sieve.6.3 The following maximum heating rates at temperaturesbelow 1500 F (815 C) are recommended:Cross Section of Specimen Maximum Heating Ratein. mm F/h C/h412 by 3 114 by 76 100 55412 by 212 114 by
21、 64 100 552 by 2 51 by 51 300 1701 by 1 25 by 25 700 380At temperatures over 1500 F, a heating rate up to 700 F(390 C) h is permissible. Generally, a slower heating rate doesnot affect the properties of the specimens adversely. Thus,when smaller and larger specimens are fired together, theheating ra
22、te applicable to the larger specimens should be used.NOTE 2Different heating rates are specified for various samples toensure that the difference in temperature between the center and thesurface of the specimen does not exceed 45 F (25 C). Experimentalevidence indicates that cracking may occur when
23、a castable sample isheated too rapidly. The safe heat-up rate increases with decreasing samplesize.6.4 Hold the specimens at the specified temperature for 5 h.During the holding period, a furnace atmosphere containing aminimum of 0.5 % oxygen with 0 % combustibles should bemaintained. For special hi
24、gh-temperature tests, a longer orshorter holding time may be required. Please refer to theappropriate test method for details.6.5 Measure the temperature within the kiln by means of anappropriate calibrated thermocouple. Refer to SpecificationE230, Tables 1 and 2, for tolerances and upper temperatur
25、elimits for use of various thermocouples. An alternative methodis the use of a calibrated optical pyrometer where applicable.Make temperature readings at intervals of 15 min or less whenthe temperature is not recorded and controlled automatically.The use of cone plaques is advised as a guide to temp
26、eratureuniformity within the kiln.6.6 After completion of the firing, cool the specimens in aclosed kiln at a cooling rate not exceeding 500 F (280 C) h.7. Keywords7.1 castables; refractory concreteASTM International takes no position respecting the validity of any patent rights asserted in connecti
27、on 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 time by the responsible
28、 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 will receive careful consi
29、deration 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 ASTM International, 100 Ba
30、rr 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 172Mon Apr 30 54
