ASTM_B_916_-_01_2017.pdf

Designation:B91601(Reapproved 2017)Standard Test Method forAdherence of Porcelain Enamel Coatings to Sheet Metal1This standard is issued under the fixed designation B916;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 purpose of this test is to provide a standardized procedure to determine and rate the impactadhesion of porcelain enamels on sheet steel.1.Scope1.1 The scope of this test method is:1.1.1 To determine quantitatively the amount of enamelremaining after the porcelain enamel coating specimen hasbeen deformed;1.1.2 To standardize the deformation parameters for testingadherence of porcelain enamel to sheet metal;and,1.1.3 To provide a quantitative adherence rating scale forcomparison to reference standards.1.2 This adherence test method is applicable to porcelainenamel coatings on substrates from 18 to 24 gauge(0.0478 to0.025 in.or from 1.214 to 0.654 mm).1.3 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 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.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Significance and Use2.1 The measurement of adherence in porcelain enamelsystems,such as ground coat,ground coat/cover coat,anddirect-on cover-coat enamels,is an important procedure formonitoring process variables in metal preparation,enamelapplication thickness,steel selection,and enamel selection,aswell as assuring the ultimate quality of the finished product.3.Apparatus3.1 Drop Weight Deformation Device2,see Figs.1 and 2.3.2 The drop weight deformation device as shown in Fig.1shall impart a single impact blow from a hemisphericalindenter to a coated specimen supported over a sharp-edgedbottomless die.The area of the deformation and the concomi-cant damage to the coating is largely influenced by the size ofthe hemispherical indenter;the die opening size and edgesharpness;and,the energy of the blow at impact.3.3 A satisfactory degree of deformation and damage areobtained if the conditions in 3.2 use the following parameters:0.50 in.(12.7 mm)diameter hemispherical indenter,0.75 in.(19.1 mm)diameter bottomless die(lower plunger guide inFig.1)with sharp edge,and 80 in./lb(9.03 J)energy at impact.3.4 Deformation Devices,of other designs may be usedprovided that the parameters in 3.3 are used.3.5 Adherence Reference Standards,see 7.1.4.Test Specimens4.1 The test specimens shall be flat enameled panels not lessin size than 4 in.2(101.6 mm2).Larger sizes and shapes may beused provided that a flat surface can be held firmly against andparallel to the lower plunger guide during deformation.5.Safety Precautions5.1 During the procedure in 6.1,fine enameled chips may bereleased with some force from the steel surface;therefore,it is1This test method is under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 onMaterials for Porcelain Enamel and Ceramic-Metal Systems.Current edition approved May 1,2017.Published May 2017.Originallyapproved in 2001.Last previous edition approved in 2013 as B916 07(2013)1.DOI:10.1520/B0916-01R17.2A drop weight device that has been found suitable is available from PacificScientific Co.,Gardner/Neotech Instrument Div.,2431 Linden Lane,Silver Spring,MD 20910.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis 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(TBT)Committee.1 recommended that personnel in the immediate vicinity of thetest wear safety goggles.6.Procedure6.1 Specimen DeformationThe hammer weight of thesuggested drop weight device is 5 lb(2268 g),which requiresa 16 in.(406.4 mm)drop distance to yield the specified 80in./lb(9.03 J)energy at impact.The hammer weight of the dropweight device may range from 2 to 8 lb(907 to 3629 g).If thehammer weight is within this range,but not 5 lb,calcula