ASTM_A_630_-_16ae1.pdf

Designation:A63016a1Standard Test Methods forDetermination of Tin Coating Weights for Electrolytic TinPlate1This standard is issued under the fixed designation A630;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1NOTEA Summary of Changes was added editorially in January 2017.INTRODUCTIONFour test methods for determination of tin coating weights are described.These are typical methodsand represent those most commonly used in the tin plate industry.Publication of these test methodsis not intended to preclude the use of any other methods such as X-ray fluorescence measurementsystems for control purposes by the consumer or supplier.However,in case of dispute,the refereemethod is to be used to determine conformance to Specification A624/A624M and SpecificationA626/A626M.Sampling procedures for tin coating-weight testing and applicable standards for the specific classdesignation are outlined in Specification A624/A624M and Specification A626/A626M.1.Scope*1.1 These test methods include four methods for the deter-mination of tin coating weights for electrolytic tin plate asfollows:Test MethodSectionsABendix Test Method3 to 9BConstant-Current,Electrolytic Test Method(Referee Method)10 to 17CSellars Test Method18 to 27DTitration Test Method28 to 361.2 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.1.3 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:2A624/A624M Specification for Tin Mill Products,Electro-lytic Tin Plate,Single ReducedA626/A626M Specification for Tin Mill Products,Electro-lytic Tin Plate,Double ReducedD1125 Test Methods for Electrical Conductivity and Resis-tivity of WaterMETHOD ADETERMINATION OF THE TINCOATING WEIGHTS BY THE BENDIX TESTMETHOD3.Scope3.1 This test method covers the determination of tin coatingweights on steel plate.4.Summary of Test Method4.1 The procedure involves dissolution of tin from a tinplate anode in a dilute hydrochloric acid solution containing a1These test methods are under the jurisdiction of ASTM Committee A01 onSteel,Stainless Steel and Related Alloys and are the direct responsibility ofSubcommittee A01.20 on Tin Mill Products.Current edition approved Dec.1,2016.Published December 2016.Originallyapproved in 1968.Last previous edition approved in 2016 as A630-16.DOI:10.1520/A0630-16AE01.2For 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.*A Summary of Changes section appears at the end of this standardCopyright 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 measured excess of standard potassium iodate-potassium io-dide solution.Excess iodine from the iodate-iodide solution isback titrated with standard sodium thiosulfate using a starchindicator.5.Apparatus35.1 The detinning cell consists essentially of two cathodesof carbon rod,the sample that serves as an anode,and a beakerof dilute hydrochloric acid electrolyte.The carbon rods(6 by0.25 in.or 152 by 6.35 mm,encased in porous porcelainthimbles)are suspended from a suitable frame about 1 in.(25 mm)apart.A small glass-enclosed magnet is attached tothe frame in such a manner that it will hold the samplesuspended midway between the two cathodes.A movableplatform permits the beaker of electrolyte to be brought uparound the assembly so that the sample will be completelyimmersed.5.2 Asource of direct current that can be regulated to supplyup to 3 A at 3 to 5 V through the deplater is required.5.3 Although regular laboratory glassware can be used,it isadvisable to use automatic dispensing pipets or burets,amotor-driven stirrer for titrations,and a timing switch whenlarge numbers of determinations are to be made.5.4 PrecautionsThe apparatus must be kept in continuousoperation to prevent iron in the solution adhering to the porouscells from oxi