ASTM A719/A719M-02

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Designation:A719/A719M–02
Standard Test Method for
1
Lamination Factor of Magnetic Materials
This standard is issued under the fixed designationA 719/A 719M; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Significance and Use
1.1 This test method covers measurement of the lamination 4.1 Lamination factor, S, indicates the deficiency of effec-
factor (Note 1) of a specimen composed of strips cut from tive steel volume which is due to the presence of oxides,
magnetic material. roughness, insulating coatings, and other conditions affecting
the steel surface.
NOTE 1—Lamination factor is also termed space factor or stacking
factor.
5. Apparatus
1.2 This test method shall be used in conjunction with
5.1 Testing Machine—A compression testing machine or
Practice A 34/A 34M.
other compression device capable of exerting the specified
1.3 The values and equations stated in customary (cgs-emu
pressure.
and inch-pound) or SI units are to be regarded separately as
5.2 Metal Plates—Two flat, smooth, rigid metal plates with
standard. Within this test method, SI units are shown in
square edges and ends are required. They shall be of sufficient
brackets. The values stated in each system may not be exact
stiffness to distribute the pressure uniformly over the surface of
equivalents; therefore each system shall be used independently
the sample. Each plate shall be 8.46 in. [215 mm] long and
of the other. Combining values from the two systems may
have a minimum width of 1.97 in. [50 mm] so that the area of
result in nonconformance with this test method.
strips under pressure when testing 1.18-in. [30-mm] wide
1.4 This standard does not purport to address the safety 2 2
specimens will be 10 in. [6450 mm ].
concerns associated with its use. It is the responsibility of the
5.2.1 Extensions can be added to the plates to allow the use
user of this standard to establish appropriate safety and health
of micrometers or outside calipers instead of inside calipers for
practices and determine the applicability of regulatory limita-
determining plate separation. Precautions must be taken to
tions prior to use.
ensure that, within the limits of accuracy of the measurements,
no significant deflection of these extensions result from the test
2. Referenced Documents
pressure.
2.1 ASTM Standards:
5.3 Length-Measuring Tools—Calipers or other devices of
A 34/A 34M Practice for Sample and Procurement Testing
adequate accuracy for measurement of plate separation.
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of Magnetic Materials
6. Sampling
3. Summary of Test Method
6.1 Test strips shall be selected as representative of the
3.1 The laminated test specimen is subjected to pressure in
surface condition. Core loss test specimens (Epstein test
a compression device and the resulting volume is then deter-
specimens) are normally used for this purpose.
mined from the measured specimen height, width, and length.
6.2 In routine testing, where the core loss specimens are too
An equivalent solid volume is calculated from the specimen
small to conform to the number of strips requirement of Table
mass and the true density of the specimen material.The ratio of
1, sufficient specimens may be combined to provide an
the calculated (equivalent solid) volume to the measured
adequate test specimen. The combined specimens must be of
volume is the lamination factor.
the same thickness and material, have similar surfaces, and be
representative of the surface condition of the test lot.
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6.3 When a referee test becomes necessary, the test speci-
This test method is under the jurisdiction of ASTM Committee A06 on
Magnetic Properties and is the direct responsibility of SubcommitteeA06.01 onTest
men must be composed of strips taken from one lot of steel. It
Methods.
must be representative of the surface condition, thickness, and
Current edition approved Oct. 10, 2002. Published November 2002. Originally
other variables. The shearing burrs should be removed and the
published as A 719–75. Last previous edition A 719–97.
2
strips wiped free of loose particles.
Annual Book of ASTM Standards, Vol 03.04.
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A719/A719M–02
TABLE 1 Number of Strips in Lamination Factor Test Specimens
8.6.1 When using a compression testing machine make four
Number of measurements of the separation, one at each corner of the
Thickness
Electrical Sheet
Strips per
A
backing plates.
Gage Number
in. [mm]
Test Specimen
8.6.2 When using a compression device design
...