ASTM_C_632_-_88_2016.pdf

Designation:C63288(Reapproved 2016)Standard Test Method forReboiling Tendency of Sheet Steel for Porcelain Enameling1This standard is issued under the fixed designation C632;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.INTRODUCTIONThe results of this test indicate whether or not a sheet steel will cause reboiling under one given setof enameling conditions,and enable the enamel processor to establish a possible cause ofimperfections in the finished coating.This may be performed in any laboratory equipped for porcelainenamel.It does not require facilities for metal surface preparation.1.Scope1.1 This test method covers the determination of whether asheet steel for porcelain enameling will reboil under a given setof worse case conditions.1.2 The values 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-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C286 Terminology Relating to Porcelain Enamel andCeramic-Metal Systems3.Terminology3.1 Definitions:3.1.1 ground coata porcelain enamel applied directly tothe base metal to function as an intermediate layer between themetal and the cover coat(see Terminology C286).3.1.2 reboilinggas evolution occurring and recurring dur-ing repeated firing of the ground coat,sometimes a defect(seeTerminology C286).3.1.3 slip(slurry)a suspension of finely divided materialin liquid(see Terminology C286).3.2 Definitions of Terms Specific to This Standard:3.2.1 quarter linesimaginary lines parallel to the directionof rolling positioned at a distance from the sheet mill edge,equal to one quarter of the sheet width.4.Summary of Test Method4.1 Both surfaces of sheet steel sample plates are subjectedto a cleaning treatment and are then porcelain enameled with asheet-steel,ground-coat type finish.Subsequent reheating atvarious times is performed to reveal whether or not the steelwill cause reboiling.The presence or absence of reboiling isdetermined by visual inspection.5.Significance and Use5.1 The results of this test indicate whether or not a sheetsteel will cause reboiling under one given set of enamelingconditions and enable the enamel processor to establish apossible source of imperfections in the finished coating.5.2 This test method is normally used to test samples fromlots,coils,or lifts of sheet steel which for some reason,production problems,defects evident on enameled parts,orproduction experience are suspected of causing defects inenameled ware which have the appearance of reboiling.It isoften used to establish whether a problem exists with the baresteel or other factors such as the porcelain enamel,processingcontamination,and so forth.6.Apparatus6.1 This test can be conducted in any laboratory equippedfor general porcelain enameling.It does not require facilitiesfor metal surface preparation.7.Reagents and Materials7.1 Steel Sheet,sufficient in size to provide samples asdescribed in 8.1 and 8.1.1.1This test method is under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatingsand is the direct responsibility of Subcommittee B08.12 onMaterials for Porcelain Enamel and Ceramic-Metal Systems.Current edition approved Nov.1,2016.Published November 2016.Originallyapproved in 1969.Last previous edition approved in 2011 as C632 88(2011).DOI:10.1520/C0632-88R16.2For 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 7.2 Porcelain-Enamel,Ground-Coat Slip,obtained fromproduction milling or prepared in laboratory facilities.7.3 Acetone or Isopropyl Alcohol,reagent grade.8.Sampling8.1 Shear sufficient material from within the quarter lines ofa selected steel sheet sample from a sheet,coil,or lift to betested to provide a minimum of five panels,each at least 2 in.(50 mm)square but not greater than 4 by 6 in.(100 by 150mm).8.1.1 Choose panels from rust-free areas that do not containthe mill identification stamp.8.1.2 Identify each panel by a method that enables identityto be monitored after repeated enamel firings.Steel diestamping is the most commonly used technique.8.1.3 Material sheared from the sheet or coil may be withinthe range of sizes given in 8.1 or may be sheared intospecimens of these sizes after applica