1、Designation: C 987 00a (Reapproved 2005)Standard Practice forVapor Attack on Refractories for Furnace Superstructures1This standard is issued under the fixed designation C 987; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar of last revision. 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 practice covers a procedure for comparing thebehavior of refractories in contact with vapors under conditi
3、onsintended to simulate the environment within a glass melting orother type of furnace when refractories are exposed to vaporsfrom raw batch, molten glass, fuel, fuel contaminants, or othersources. This procedure is intended to accelerate serviceconditions for the purpose of determining in a relativ
4、ely shorttime the interval resistance to fluxing, bloating, shrinkage,expansion, mineral conversion, disintegration, or other physi-cal changes that may occur.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user
5、 of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Significance and Use2.1 This practice provides a guide for evaluating the resis-tance of refractories in glass melting furnace superstructures tovapor at
6、tack. This test method may also be useful for evaluat-ing refractories in other applications where vapor attackoccurs.2.2 An electric-heated furnace is recommended. Water va-por and other atmospheric components in a gas- or fuel-firedfurnace may participate in the chemical and physical reactionsbein
7、g studied. Results may differ, therefore, depending uponthe nature and type of firing employed.2.3 The degree of correlation between this practice andservice performance is not fully determinable. This is intendedto be an accelerated practice that generates a substantial degreeof reaction in a relat
8、ively short amount of time. This accelera-tion may be accomplished by changing the composition and/orconcentration of the reactants, increasing temperatures, or byperforming the test in an isothermal environment.2.4 Since the practice may not accurately simulate theservice environment, observed resu
9、lts of this practice may notbe representative of those found in service. It is imperative thatthe user understand and consider how the results of thispractice may differ from those encountered in service. This isparticularly likely if the reaction products, their nature, or theirdegree differ from t
10、hose normally found in the actual serviceenvironment.2.5 It is incumbent upon the user to understand that this isan aggressive, accelerated practice and to be careful in inter-preting the results. If, for example, the reaction species havenever been found in a real world furnace, then this practices
11、hould not necessarily be considered valid to evaluate therefractory in question.3. Apparatus3.1 The crucible for containing the reactant shall be a densealumina or platinum crucible of conical shape with dimensionsof 43 mm in diameter at top, 33 mm in diameter at bottom, and53 mm high.3.2 The crucib
12、le-cover assembly (Fig. 1) may be supportedwithin a suitable refractory holding crucible (Fig. 2) such asmullite to maintain the position of the cover, if an excessiveamount of glass phase reaction product is anticipated.3.3 The electric heating chamber shall be of sufficient sizeto accommodate at l
13、east three assemblies for comparativeevaluation. The temperature control system shall be capable ofmaintaining a desired holding temperature with a tolerance of63C.4. Specimen Preparation4.1 The test specimen shall conform to the followingdimensions with major faces cut or ground parallel and flat t
14、oform a tight seal with top of crucible:4.1.1 Length, 55 6 2 mm,4.1.2 Width, 55 6 2 mm, and4.1.3 Thickness, 20 6 1.0 mm.4.2 SelectionUse specimens that are free of defects suchas cracks, fissures, and voids. Where obvious defects inspecimens appear after testing is completed, disregard theresults an
15、d repeat the test.4.3 Three specimens of a refractory brand shall constitute atest.1This practice is under the jurisdiction ofASTM Committee C08 on Refractoriesand is the direct responsibility of Subcommittee C08.10 on Refractories for Glass.Current edition approved March 1, 2005. Published March 20
16、05. Originallyapproved in 1983. Last previous edition approved in 2000 as C 987 00a.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Procedure5.1 The reactant shall be selected such that the vaporgenerated during the test is simila
17、r to the vapor encountered inservice. Some reactants that have been found suitable for thispurpose are: carbonates, sulphates, borates, and halides.5.2 For comparative evaluations, a consistent weight ofreactant is to be used. The level of the reactant is not to exceed40 % of the depth of the crucib
18、le in order to avoid contactbetween the molten reactant and the specimen. An example ofa suitable quantity of reactant is 12.5 g of technical gradesodium carbonate.5.2.1 Use molar equivalents for alternative reactants provid-ing that the level of this reactant does not exceed 40 % of thecrucible dep
19、th.5.2.2 The test temperature shall be appropriate to thereactant and the environment to be simulated. For example, atemperature of 1370C has been found to give measurableresults when using a sodium carbonate reactant.5.3 Place a weighed amount of reactant in a crucible.5.4 Assemble the crucible and
20、 the specimen, and place it ona level furnace hearth. An assembly having a test specimenwith a silica content greater than 50 % should be placed in aholding crucible to prevent disorientation by glass phasedevelopment (see Fig. 2).5.5 A consistent heating rate of 2 to8htotest temperatureand a durati
21、on of 24 h at temperature shall constitute the test.Allow the crucible assembly to cool in a manner that preventsthermal shock.5.6 Separate the sample from the reactant crucible aftercooling.6. Report6.1 Report the following information:6.1.1 Materials tested,6.1.2 Test temperature,6.1.3 Type and qu
22、antity of reactant(s), and6.1.4 Observations as to the condition of the specimens aftertesting. It may be desirable to cut the specimens in half andexpose a cross-sectional view.6.1.4.1 These observations may be, but are not limited to:photographs, written comments, change of weight of speci-mens, c
23、hange of dimensions of specimens, change of flatnessof specimens, change of mineralogy, and development ofcracks in specimens.7. Precision and Bias7.1 PrecisionNo justifiable statement of precision is pos-sible since the results of this test method are word descriptionsrather than numerical values.7
24、.2 BiasNo justifiable statement of bias is possible sincea true value of refractory attack by vapor cannot be establishedby an accepted reference sample.8. Keywords8.1 corrosion; glass; refractories; superstructures; vaporattackFIG. 1 Crucible-Cover AssemblyFIG. 2 Refractory Holding CrucibleC 987 00
25、a (2005)2ASTM 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 determination of the validity of any such patent rights, and the riskof infringement of such ri
26、ghts, 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, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additiona
27、l standardsand should be addressed to ASTM International Headquarters. Your comments will 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 AST
28、M 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 987 00a (2005)3
