ASTM_C_987_-_10_2015.pdf

Designation:C98710(Reapproved 2015)Standard Test Method forVapor Attack on Refractories for Furnace Superstructures1This standard is issued under the fixed designation C987;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 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 covers a procedure for comparing thebehavior of refractories in contact with vapors under conditionsintended 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 relatively shorttime the interval resistance to fluxing,bloating,shrinkage,expansion,mineral conversion,disintegration,or other physi-cal changes that may occur.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 determine the applica-bility of regulatory limitations prior to use.2.Significance and Use2.1 This test method provides a guide for evaluating theresistance of refractories in glass melting furnace superstruc-tures to vapor attack.This test method may also be useful forevaluating 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 reactionsbeing studied.Results may differ,therefore,depending uponthe nature and type of firing employed.2.3 The degree of correlation between this test method andservice performance is not fully determinable.This is intendedto be an accelerated test method that generates a substantialdegree of reaction in a relatively short amount of time.Thisacceleration may be accomplished by changing the composi-tion and/or concentration of the reactants,increasingtemperatures,or by performing the test in an isothermalenvironment.2.4 Since the test method may not accurately simulate theservice environment,observed results of this test method maynot be representative of those found in service.It is imperativethat the user understand and consider how the results of thistest method may differ from those encountered in service.Thisis particularly likely if the reaction products,their nature,ortheir degree differ from those normally found in the actualservice environment.2.5 It is incumbent upon the user to understand that this isan aggressive,accelerated test method and to be careful ininterpreting the results.If,for example,the reaction specieshave never been found in a real world furnace,then this testmethod should not necessarily be considered valid to evaluatethe refractory 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 crucible-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 least 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 toform 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 in1This test method is under the jurisdiction of ASTM Committee C08 onRefractories and is the direct responsibility of Subcommittee C08.10 on Refractoriesfor Glass.Current edition approved Oct.1,2015.Published October 2015.Originallyapproved in 1983.Last previous edition approved in 2010 as C987 10.DOI:10.1520/C0987-10R15.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 specimens appear after testing is completed,disregard theresults and repeat the test.4.3 Three specimens of a refractory brand shall constitute atest.5.Procedure5.1 The reactant shall be selected such that the vaporgenerated during the test is similar to the vapor encountered inservice.Some reactants that have been found suitable for thispurpose are:carb