ASTM_A_971_-_A_971M_-_10.pdf

Designation:A971/A971M10Standard Test Method forMeasuring Edge Taper and Crown of Flat-Rolled ElectricalSteel Coils1This standard is issued under the fixed designation A971/A971M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method provides a procedure for measuringedge taper and crown of flat-rolled electrical steel coils asproduced at the steel mill.1.2 The values and equations stated in customary(cgs-emuand inch-pound)units or SI units are to be regarded separatelyas standard.Within this standard,the SI units are shown inbrackets.The values stated in each system may not be exactequivalents;therefore,each system shall be used independentlyof the other.Combining values from the two systems mayresult in nonconformance with this standard.1.3 The following material specifications include require-ments for edge taper or crown:A677,A683,A726,A840,andA876.1.4 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.2.Referenced Documents2.1 ASTM Standards:2A340 Terminology of Symbols and Definitions Relating toMagnetic TestingA677 Specification for Nonoriented Electrical Steel FullyProcessed TypesA683 Specification for Nonoriented Electrical Steel,Semi-processed TypesA726 Specification for Cold-Rolled Magnetic LaminationQuality Steel,Semiprocessed TypesA840 Specification for Fully Processed Magnetic Lamina-tion Steel(Withdrawn 2011)3A876 Specification for Flat-Rolled,Grain-Oriented,Silicon-Iron,Electrical Steel,Fully Processed Types3.Terminology3.1 Definitions:Except as defined as follows,the symbolsand terminology used in this test method are defined inTerminology A340.3.1.1 edge taper and crownthe variations of thicknessacross the widths of cold-rolled steel coils,that is,perpendicu-lar to the rolling direction.Edge taper and crown are not thesame as thickness variation.Thickness variation is measuredparallel to the rolling direction(although it is loosely defined asvariation in any direction).See Fig.1.3.1.1.1 crownthe variation of thickness from the edge tothe center,perpendicular to the rolling direction.3.1.1.2 edge taperthe variation of thickness from the edgeto approximately 4 in.100 mm from the edge of the coil.3.1.1.3 edge taper gamma()the slope of the edge taper(adimensionless number)expressed in ten thousandths of a unitper unit.3.1.2 edge trimmingthe slitting of a narrow strip fromeach edge of the master coil for discard.This reduces the edgetaper gamma on the remainder of the coil.3.1.3 gamma stripa 1 to 4 in.25 to 102 mm strip cutacross the full width of the master coil(or master coil coupon),for the purpose of measuring edge taper and crown.3.1.4 master coilsfull-width coils as produced by cold-rolling mills.Slit coils are narrower width coils slit from amaster coil.A master coil coupon is a full-width piece of themaster coil,usually manually cut off for test purposes.4.Summary of Test Method4.1 In determining the edge taper and crown,a gamma stripis taken from the coil head and tail.Thickness readings aretaken using a micrometer or other measuring device along asingle line perpendicular to the rolling direction at points38,138,238,and 438in.10,35,60,and 111 mm from each edge1This test method is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsibility of Subcommittee A06.01 on TestMethods.Current edition approved Nov.1,2010.Published January 2011.Originallyapproved in 1997.Last previous edition approved in 2005 as A971/A971M05.DOI:10.1520/A0971_A0971M-10.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 to determine edge taper and in the center to determine crown.The readings are recorded,and variations between the readingscalculated.If the edge taper is greater than specified,edgetrimming can be performed to meet the limits agreed uponbetween the producer and the user.5.Significance and Use5.1 Flat-rolled electrical steel master coils are usually slitinto narrower coils.Usually these slit coils are punched orsheared into laminations of various shapes.The laminations arethen uniformly stacked to become the cores of magneticdevices such as motors and transformers.Stacking of manylaminations exhibiting ex