1、Designation: A971/A971M 10A971/A971M 17Standard 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 o
2、f 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 measuring edge taper and crown of flat-rolled electr
3、ical steel coils as producedat the steel mill.1.2 The values and equations stated in customary (cgs-emu and inch-pound) units or SI units are to be regarded separately asstandard. Within this standard, the SI units are shown in brackets. The values stated in each system may not be exact equivalents;
4、therefore, each system shall be used independently of the other. Combining values from the two systems may result innonconformance with this standard.1.3 The following material specifications include requirements for edge taper or crown: A677, A683, A726, A840A876, andA876A1086. Specification A840 a
5、lso includes requirements for edge taper or crown, but it has been withdrawn and reference toit is included for historical purposes.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to estab
6、lish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Prin
7、ciples for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A340 Terminology of Symbols and Definitions Relating to Magnetic TestingA677 Specification fo
8、r Nonoriented Electrical Steel Fully Processed TypesA683 Specification for Nonoriented Electrical Steel, Semiprocessed TypesA726 Specification for Cold-Rolled Magnetic Lamination Quality Steel, Semiprocessed TypesA840 Specification for Fully Processed Magnetic Lamination Steel (Withdrawn 2011)3A876
9、Specification for Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed TypesA1086 Specification for Thin-Gauge Nonoriented Electrical Steel Fully Processed Types3. Terminology3.1 Definitions: Except as defined as follows, the symbols and terminology used in this test method a
10、re defined in TerminologyA340.3.1.1 edge taper and crownthe variations of thickness across the widths of cold-rolled steel coils, that is, perpendicular to therolling direction. Edge taper and crown are not the same as thickness variation. Thickness variation is measured parallel to therolling direc
11、tion (although it is loosely defined as variation in any direction). See Fig. 1.3.1.1.1 crownthe variation of thickness from the edge to the center, perpendicular to the rolling direction.3.1.1.2 edge taperthe variation of thickness from the edge to approximately 4 in. 100 mm from the edge of the co
12、il.1 This test method is under the jurisdiction of ASTM Committee A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.01 on Test Methods.Current edition approved Nov. 1, 2010Oct. 1, 2017. Published January 2011November 2017. Originally approved in 1997. Last previous edit
13、ion approved in 20052010as A971/A971MA971/A971M 10.05. DOI: 10.1520/A0971_A0971M-10.10.1520/A0971_A0971M-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the stand
14、ards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version
15、. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International,
16、 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1.3 edge taper gamma ()the slope of the edge taper (a dimensionless number) expressed in ten thousandths of a unit perunit.3.1.2 edge trimmingthe slitting of a narrow strip from each edge of the master coil for
17、discard. This reduces the edge tapergamma on the remainder of the coil.3.1.3 gamma stripa 1 to 4 in. 25 to 102 mm strip cut across the full width of the master coil (or master coil coupon), forthe purpose of measuring edge taper and crown.3.1.4 master coilsfull-width coils as produced by cold-rollin
18、g mills. Slit coils are narrower width coils slit from a master coil.A master coil coupon is a full-width piece of the master coil, usually manually cut off for test purposes.4. Summary of Test Method4.1 In determining the edge taper and crown, a gamma strip is taken from the coil head and tail. Thi
19、ckness readings are takenusing a micrometer or other measuring device along a single line perpendicular to the rolling direction at points 38, 138, 238, and438 in. 10, 35, 60, and 111 mm from each edge to determine edge taper and in the center to determine crown. The readings arerecorded, and variat
20、ions between the readings calculated. If the edge taper is greater than specified, edge trimming can beperformed to meet the limits agreed upon between the producer and the user.5. Significance and Use5.1 Flat-rolled electrical steel master coils are usually slit into narrower coils. Usually these s
21、lit coils are punched or shearedinto laminations of various shapes. The laminations are then uniformly stacked to become the cores of magnetic devices such asmotors and transformers. Stacking of many laminations exhibiting excessive taper causes assembly problems and poor appearance.Nonuniform stack
22、 lengths in motors cause imbalance and noise. When the laminations are interleaved in transformers, taper causesair spaces within the core resulting in increased noise, increased exciting current, and higher core loss.6. Interference6.1 This test method assumes that edge taper and crown are consiste
23、nt through each individual coil. If different coils are weldedtogether to make up a finished coil, this may not be the case. Nevertheless, edge trim can be used to correct for inconsistencies.7. Description of Gamma Strip and Equipment Required7.1 A coupon is cut from head and tail ends of the maste
24、r coil. A shear in good working condition with sufficient capacity isused to cut a gamma strip from the coupon. The shear can be fitted with an edge guide or other means to establish a stripperpendicular to the coil edges. Perpendicularity shall be within 1. See Fig. 2.7.2 Means for locating and mar
25、king the gamma strip measurement points shall be provided. A template can be made that willquickly locate for marking the test points from each edge. The center point can be located with a scale. Points shall be located towithin 0.032 in. 0.81 mm. See Fig. 3. Alternatively, a machine may be construc
26、ted that automatically locates all nine points onthe gamma strip, measures the points, and records/displays the data. If a continuous sequence of measurements are taken over thelength of the strip (thickness profile), then the specified nine points shall be read from the recorded data.7.3 Amicromete
27、r or other thickness measuring device shall be provided. The micrometer shall have anvils that are convex witha radius no less than 0.062 inin. 1.6 mm. Operation may be manual or automatic as part of a system of fixtures, gaging devices,and data acquisition instruments. Thickness measurement device
28、repeatability shall be 100 in. 2.54 m (on precision gageblock).NOTE 1Roughness of the steel sheet surface can affect repeatability.FIG. 1 Typical Steel Mill Coil Thickness Profile across Width of CoilA971/A971M 1727.4 A data sheet or computer printout shall be provided for entry of thickness reading
29、s and computation of gamma for thegamma strip.8. Procedure8.1 Measure and record the data for all nine points previously specified.9. Calculation9.1 Calculate edge taper gamma as follows:5XW 2 Y!W 104 (1)where: (gamma) = edge taper gamma,Xw = thickness at distance W from Y, in in. mm, andY = thickne
30、ss at 38 in. 10 mm from the edge, in in. 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):crown5XC 2 Y (2)wher
31、e:Y = average of the thicknesses 38 in. 10 mm from each edge, in in. mm andXc = thickness at center, in in. mm.The crown is measured at the center of the gamma strip and is substantially the thickest point across its width. Crown ismeasured the same way as edge taper except the distance Wcis between
32、 measurement pointsXcandY.FIG. 2 Typical Gamma StripNOTE 1Measurement points for opposite edge of gamma strip are the mirror image of the edge shown.FIG. 3 Measurement Points Marked on Gamma StripA971/A971M 1739.3 Calculate edge taper as follows (see Fig. 4):edge taper5X4 2 Y (3)where:X4 = thickness
33、 at 438 in. 110 mm from the edge, in in. mm, andY = thickness at 38 in. 10 mm from the edge, in in. mm.10. Interpretation of Results10.1 Edge taper gamma exceeding agreed upon limits can usually be corrected by edge trimming an amount sufficient to bringthe coil into specification. Each edge of the
34、coil shall be considered separately for the amount of trim. After trimming, this samemethod can again be followed.11. Precision and Bias11.1 This test method, although being followed by several steel mills and their customers, has not yet been the subject of acomparison of the same samples at severa
35、l laboratories (round robin). However, a computerized instrument that adheres to this testmethod has been in use in at least three laboratories and supplier laboratories. At the time of preparation of this test method,correlation has been achieved between three such instruments to 0.0002-in. 5-m tol
36、erance for several samples of steel coils.However, no statement of precision and bias is made at this time.12. Keywords12.1 coupon; crown; edge taper; edge trim; gamma strip; master coil; slit coilASTM International takes no position respecting the validity of any patent rights asserted in connectio
37、n with any item mentionedin this standard. 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
38、technical committee and must be reviewed 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 conside
39、ration at a meeting of theresponsible 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
40、 Harbor Drive, PO Box C700, West Conshohocken, 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 4 Edge Taper/Crown DimensionsA971/A971M 174
