ASTM A971 / A971M - 10

    Standard Test Method for Measuring Edge Taper and Crown of Flat-Rolled Electrical Steel Coils

    Active Standard ASTM A971 / A971M | Developed by Subcommittee: A06.01

    Book of Standards Volume: 03.04


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    Significance and Use

    Flat-rolled electrical steel master coils are usually slit into narrower coils. Usually these slit coils are punched or sheared into laminations of various shapes. The laminations are then uniformly stacked to become the cores of magnetic devices such as motors and transformers. Stacking of many laminations exhibiting excessive taper causes assembly problems and poor appearance. Nonuniform stack lengths in motors cause imbalance and noise. When the laminations are interleaved in transformers, taper causes air spaces within the core resulting in increased noise, increased exciting current, and higher core loss.

    1. Scope

    1.1 This test method provides a procedure for measuring edge taper and crown of flat-rolled electrical steel coils as produced at 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 as standard. Within this standard, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with this standard.

    1.3 The following material specifications include requirements for edge taper or crown: A677, A683, A726, A840, and A876.

    1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    A340 Terminology of Symbols and Definitions Relating to Magnetic Testing

    A677 Specification for Nonoriented Electrical Steel Fully Processed Types

    A683 Specification for Nonoriented Electrical Steel, Semiprocessed Types

    A726 Specification for Cold-Rolled Magnetic Lamination Quality Steel, Semiprocessed Types

    A840 Specification for Fully Processed Magnetic Lamination Steel

    A876 Specification for Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types


    ICS Code

    ICS Number Code 77.140.50 (Flat steel products and semi-products)

    UNSPSC Code

    UNSPSC Code 31380000(Magnets and magnetic materials)


    DOI: 10.1520/A0971_A0971M-10

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