ASTM A971/A971M-05

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

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. Uniform 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, exciting current, and core loss.
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: A 677, A 683, A 726, A 840/A 840M, and A 876.
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.

General Information

• Status: Historical
• Publication Date: 14-Dec-2005
• ICS: 77.140.50 - Flat steel products and semi-products
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.01 - Test Methods

Relations

• Replaces: ASTM A971-00 - Standard Test Method for Measuring Edge Taper and Crown of Flat-Rolled Electrical Steel Coils
• Effective Date: 15-Dec-2005
• Replaced By: ASTM A971/A971M-10 - Standard Test Method for Measuring Edge Taper and Crown of Flat-Rolled Electrical Steel Coils
• Effective Date: 01-Nov-2010
• Referred By: ASTM A345-19 - Standard Specification for Flat-Rolled Electrical Steels for Magnetic Applications
• Effective Date: 15-Dec-2005
• Referred By: ASTM A1086-20 - Standard Specification for Thin-Gauge Nonoriented Electrical Steel Fully Processed Types
• Effective Date: 15-Dec-2005
• Referred By: ASTM A677-16 - Standard Specification for Nonoriented Electrical Steel Fully Processed Types
• Effective Date: 15-Dec-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: A971/A971M – 05
Standard Test Method for
Measuring Edge Taper and Crown of Flat-Rolled Electrical
1
Steel Coils
This standard is issued under the fixed designationA971/A971M; the number immediately following the designation indicates the year
of 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. Scope A876 Specification for Flat-Rolled, Grain-Oriented,
Silicon-Iron, Electrical Steel, Fully Processed Types
1.1 This test method provides a procedure for measuring
edge taper and crown of flat-rolled electrical steel coils as
3. Terminology
produced at the steel mill.
3.1 Definitions: Except as defined as follows, the symbols
1.2 The values and equations stated in customary (cgs-emu
and terminology used in this test method are defined in
and inch-pound) units or SI units are to be regarded separately
Terminology A340.
as standard. Within this standard, the SI units are shown in
3.1.1 edge taper and crown—the variations of thickness
brackets. The values stated in each system may not be exact
across the widths of cold-rolled steel coils, that is, perpendicu-
equivalents;therefore,eachsystemshallbeusedindependently
lar to the rolling direction. Edge taper slope (g) is expressed in
of the other. Combining values from the two systems may
ten thousandths of an inch per inch (ten thousandths of a
result in nonconformance with this standard.
millimetre per millimetre).
1.3 The following material specifications include require-
3.1.1.1 Discussion—The variation of thickness from the
ments for edge taper or crown: A677, A683, A726, A840/
edge to approximately 4 in. [100 mm] from the edge of the coil
A840M, and A876.
is called edge taper. The variation of thickness from the center
1.4 This standard does not purport to address all of the
to the edge is called crown.
safety concerns, if any, associated with its use. It is the
3.1.1.2 Discussion—Edge taper and crown are not the same
responsibility of the user of this standard to establish appro-
as thickness variation. Thickness variation is measured parallel
priate safety and health practices and determine the applica-
to the rolling direction (although it is loosely defined as
bility of regulatory limitations prior to use.
variation in any direction).
2. Referenced Documents 3.1.2 edge trimming—the slitting of a narrow strip from
2 each edge of the master coil for discard. This reduces the edge
2.1 ASTM Standards:
taper gamma on the remainder of the master coil.
A340 Terminology of Symbols and Definitions Relating to
3.1.3 master coils—full-width coils as produced by cold-
Magnetic Testing
rolling mills. Slit coils are narrower width coils slit from a
A677 Specification for Nonoriented Electrical Steel Fully
master coil. A coupon is a full-width piece of the master coil,
Processed Types
usually manually cut off for test purposes. A sample strip 1 to
A683 Specification for Nonoriented Electrical Steel, Semi-
4 in. [25 to 102 mm] wide is sheared across the width of the
processed Types
coilfromacouponforthepurposeofmeasuringedgetaperand
A726 Specification for Cold-Rolled Magnetic Lamination
crown. This is called a gamma strip because gamma (g)isthe
Quality Steel, Semiprocessed Types
symbol used to quantify edge taper slope or rate of variation
A840/A840M Specification for Fully Processed Magnetic
with distance. See Fig. 1.
Lamination Steel
4. Summary of Test Method
1
This test method is under the jurisdiction of ASTM Committee A06 on 4.1 In determining the edge taper and crown, a sample
Magnetic Properties and is the direct responsibility of SubcommitteeA06.01 onTest
gamma strip is taken from the coil head and tail. Thickness
Methods.
readings are taken using a micrometer or other measuring
Current edition approved Dec. 15, 2005. Published January 2006. Originally
device along a single line perpendicular to the rolling direction
approved in 1997. Last previous edition approved in 2000 as A971 – 00. DOI:
3 3 3 3
10.1520/A0971_A0971M-05.
at points ⁄8,1 ⁄8,2 ⁄8 , and 4 ⁄8 in. [10, 35, 60, and 111 mm]
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
from each edge to determine edge taper and in the center to
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
determine crown. The readings are recorded, and variations
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. between the readings calculated. If the edge taper is greater
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A971/A971M – 05
FIG. 1 Typical Steel Mill Coil T
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