ASTM_C_1351M_-_96_2012.pdf

Designation:C1351M96(Reapproved 2012)Standard Test Method forMeasurement of Viscosity of Glass Between 104Pas and108Pas by Viscous Compression of a Solid Right CylinderMetric1This standard is issued under the fixed designation C1351M;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 the determination of the viscos-ity of glass from 104Pas to 108Pas by measuring the rate ofviscous compression of a small,solid cylinder.21.2 The values stated in SI units are to be regarded as thestandard.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.Referenced Documents2.1 ASTM Standards:3C338 Test Method for Softening Point of GlassC965 Practice for Measuring Viscosity of Glass Above theSoftening PointC1350M Test Method for Measurement of Viscosity ofGlass Between Softening Point and Annealing Range(Approximately 108Pas to Approximately 1013Pas)byBeam Bending(Metric)3.Terminology3.1 parallel plate viscometera device used to determinethe viscosity of glass from approximately 104Pas to 108Pasby measuring the rate of change in thickness of a cylindricalspecimen between parallel plates moving perpendicular to theircommon central axis.The equation for calculating viscosity bythe parallel plate method is:5 2Mgh530Vdh/dt!2h31V!11T!(1)where:=viscosity,Pas,M=applied load,g,g=acceleration due to gravity,980 cm/s2,t=time,s,V=specimen volume,cm3,h=specimen thickness at time t,cm,dh/dt=compression rate,cm/s,and=glass mean coefficient of thermal expansion,25C tothe measurement temperature,T,m/m/C.See Note1.NOTE1The term(1+T)corrects for the specimen dimensionalchanges due to thermal expansion.For low thermal expansion glasses,itcan be ignored.However,for a glass with an of 20 106/C at ameasurement temperature of 1000C,this term produces a correction of2%.Only an estimate of is necessary since the correction is small.Usetwice the room temperature coefficient if data are unavailable.4.Significance and Use4.1 This test method is well suited for measuring theviscosity of glasses between the range within which rotationalviscometry(see Practice C965)is useful and the range withinwhich beam bending viscometry is useful(see Test MethodC1350M).It can be used to determine the viscosity/temperature curve in the region near the softening point(seeTest Method C338).This test method is useful for providinginformation related to the behavior of glass as it is formed intoan object of commerce,and in research and development.5.Apparatus5.1 The apparatus shall consist of a furnace,a means ofcontrolling and measuring its temperature and heating rate,specimen holders and loading rod,and a means of measuringthe rate of viscous compression of the glass specimen.5.2 Furnace:5.2.1 The furnace shall be electrically heated by resistanceelements.The dimensions and details of the furnace construc-tion are not critical;its cross-section can be circular of 75 mm(3 in.)diameter or square of sides of 75 mm.The furnaceshould have a constant temperature zone that covers the1This test method is under the jurisdiction of ASTM Committee C14 on Glassand Glass Products and is the direct responsibility of Subcommittee C14.04 onPhysical and Mechanical Properties.Current edition approved March 1,2012.Published March 2012.Originallyapproved in 1996.Last previous edition approved in 2007 as C1351M-96(2007).DOI:10.1520/C1351M-96R12.2Fontana,E.H.,“A Versatile Parallel-Plate Viscometer For Glass ViscosityMeasurements to 1000C,”Bulletin of the American Ceramic Society,Vol 49,No.6,1970,pp.594597.3For 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 ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 specimen geometry,including the compression range.Differ-ences in temperature greater than 2C within the constanttemperature zone are unacceptable.5.3 Temperature Measuring and Indicating Instruments:5.3.1 For the measurement of temperature,there shall beprovided a calibrated Type K,R,or S thermocouple.Thethermocouple shall be housed in a double-bore alumina tubewith its junction placed within 5 mm of the specimen near theaxis of the furnace.The thermocouple shall be referenced to0C by means of an ice bath,and its emf measured with acalibrated potentiometer that can be read with a sensitivityequivalent to 60.1C and an accuracy of 60.5C.Precautionsshall