1、Designation: A971/A971M 10Standard 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, t
2、he 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 coi
3、ls 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
4、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
5、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 o
6、f 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 Specifica
7、tion for Fully Processed Magnetic Lamina-tion SteelA876 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
8、.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 de
9、fined 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 (g)the
10、 slope of the edge taper(a dimensionless number) expressed in ten thousandths of aunit per 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 str
11、ip 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 the
12、master 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 di
13、rection at points38 ,138 ,238 , and 438 in. 10, 35, 60, and 111 mm from each edgeto determine edge taper and in the center to determine crown.1This test method is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsibility of SubcommitteeA06.01 on TestMethods.
14、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
15、 Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.The readings are recorded, and variations between the readingscalculate
16、d. 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
17、laminations of various shapes. The laminations arethen uniformly stacked to become the cores of magneticdevices such as motors and transformers. Stacking of manylaminations exhibiting excessive taper causes assembly prob-lems and poor appearance. Nonuniform stack lengths in motorscause imbalance and
18、 noise. When the laminations are inter-leaved in transformers, taper causes air spaces within the coreresulting in increased noise, increased exciting current, andhigher core loss.6. Interference6.1 This test method assumes that edge taper and crown areconsistent through each individual coil. If dif
19、ferent coils arewelded together to make up a finished coil, this may not be thecase. Nevertheless, edge trim can be used to correct forinconsistencies.7. Description of Gamma Strip and Equipment Required7.1 A coupon is cut from head and tail ends of the mastercoil.Ashear in good working condition wi
20、th sufficient capacityis used to cut a gamma strip from the coupon. The shear can befitted with an edge guide or other means to establish a stripperpendicular to the coil edges. Perpendicularity shall bewithin 1. See Fig. 2.7.2 Means for locating and marking the gamma strip mea-surement points shall
21、 be provided.Atemplate can be made thatwill quickly locate for marking the test points from each edge.The center point can be located with a scale. Points shall belocated to within 0.032 in. 0.81 mm. See Fig. 3.Alternatively,a machine may be constructed that automatically locates allnine points on t
22、he gamma strip, measures the points, andrecords/displays the data. If a continuous sequence of measure-ments are taken over the length of the strip (thickness profile),then the specified nine points shall be read from the recordeddata.7.3 A micrometer or other thickness measuring device shallbe prov
23、ided. The micrometer shall have anvils that are convexwith a radius no less than 0.062 in 1.6 mm. Operation may bemanual or automatic as part of a system of fixtures, gagingdevices, and data acquisition instruments. Thickness measure-ment device repeatability shall be 100 in. 2.54 m (onprecision gag
24、e block).NOTE 1Roughness of the steel sheet surface can affect repeatability.7.4 A data sheet or computer printout shall be provided forentry of thickness readings and computation of gamma for thegamma strip.8. Procedure8.1 Measure and record the data for all nine points previ-ously specified.FIG. 1
25、 Typical Steel Mill Coil Thickness Profile across Width of CoilFIG. 2 Typical Gamma StripA971/A971M 1029. Calculation9.1 Calculate edge taper gamma as follows:g5XW Y!W104(1)where:g (gamma) = edge taper gamma,Xw= thickness at distance W from Y, in in. mm,andY = thickness at38 in. 10 mm from the edge,
26、 inin. mm.Thickness is measured at width increments W of 1.00, 2.00,and 4.00 in. 25.4, 50.8, and 102 mm from a point, Y,38 in. 10mm from the edge. These points are labeled X1, X2, and X4,respectively.9.2 Calculate crown as follows (see Fig. 4):crown 5 XC Y (2)where:Y = average of the thicknesses38 i
27、n. 10 mm from eachedge, in in. mm andXc= thickness at center, in in. mm.The crown is measured at the center of the gamma strip andis substantially the thickest point across its width. Crown ismeasured the same way as edge taper except the distance Wcisbetween measurement points Xcand Y.9.3 Calculate
28、 edge taper as follows (see Fig. 4):edge taper 5 X4 Y (3)where:X4= thickness at 438 in. 110 mm from the edge, in in.mm, andY = thickness at38 in. 10 mm from the edge, in in.mm.10. Interpretation of Results10.1 Edge taper gamma exceeding agreed upon limits canusually be corrected by edge trimming an
29、amount sufficient tobring the coil into specification. Each edge of the coil shall beconsidered separately for the amount of trim. After trimming,this same method can again be followed.11. Precision and Bias11.1 This test method, although being followed by severalsteel mills and their customers, has
30、 not yet been the subject ofa comparison of the same samples at several laboratories(round robin). However, a computerized instrument that ad-heres to this test method has been in use in at least threelaboratories and supplier laboratories. At the time of prepara-tion of this test method, correlatio
31、n has been achieved betweenthree such instruments to 0.0002-in. 5-m tolerance forseveral samples of steel coils. However, no statement ofprecision and bias is made at this time.12. Keywords12.1 coupon; crown; edge taper; edge trim; gamma strip;master coil; slit coilNOTE 1Measurement points for oppos
32、ite edge of gamma strip are the mirror image of the edge shown.FIG. 3 Measurement Points Marked on Gamma StripFIG. 4 Edge Taper/Crown DimensionsA971/A971M 103ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standa
33、rd. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewe
34、d every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible
35、technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh
36、ohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).A971/A971M 104
