ASTM A900/A900M-01(2018)

Standard Test Method for Lamination Factor of Amorphous Magnetic Strip

SIGNIFICANCE AND USE
3.1 Lamination factor S indicates the deficiency of effective material volume which is due to the presence of oxides, roughness, insulating coatings, and other conditions affecting the strip surface.  
3.2 This test method is used to predict the fraction of metal that is included in the volume of the firm coil wound from the specimen tape.
SCOPE
1.1 This test method covers measurements of lamination factor (Note 1) of a specimen composed of strips cut from amorphous magnetic material. It is suitable for the determination of lamination factor for thin, flat case, metallic strip ranging in width from 0.25 to 8.00 in. [6.35 mm to 203 mm] and in thickness from 0.0005 to 0.005 in. [12.7 to 127 μm].  
Note 1: Lamination factor is also termed space factor or stacking factor.  
1.2 The values and equations stated in customary (egs-emu and inch-pound) or SI units are to be regarded separately as standard. Within this standard, 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 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Apr-2018
• ICS: 29.030 - Magnetic materials
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.01 - Test Methods

Relations

• Replaces: ASTM A900/A900M-01(2012) - Standard Test Method for Lamination Factor of Amorphous Magnetic Strip
• Effective Date: 01-May-2018
• Referred By: ASTM A901-19 - Standard Specification for Amorphous Magnetic Core Alloys, Semi-Processed Types
• Effective Date: 01-May-2018

Overview

ASTM A900/A900M-01(2018): Standard Test Method for Lamination Factor of Amorphous Magnetic Strip provides a reliable method to determine the lamination factor-also called stacking factor or space factor-for strips cut from amorphous magnetic materials. The standard outlines procedures and requirements for measuring the lamination factor in thin, flat, metallic strips with widths from 0.25 to 8.00 inches (6.35 mm to 203 mm) and thicknesses from 0.0005 to 0.005 inches (12.7 to 127 µm).

Lamination factor (S) signifies any deficiencies in the effective volume of material, such as gaps from oxides, roughness, surface coatings, and other strip surface conditions. This factor is essential in predicting the fraction of metal content present in the volume of a wound coil, directly impacting magnetic performance and efficiency in applications where amorphous magnetic strips are used.

Key Topics

• Lamination Factor Definition: The lamination factor is the ratio of the calculated (equivalent solid) volume based on sample mass and density, to the physically measured volume of a stacked strip specimen.
• Test Scope: Applicable for thin, flat amorphous metal strips across defined size ranges, this standard ensures that both SI and inch-pound units can be used independently for measurement and calculation.
• Significance: The lamination factor serves as a measure of effective material volume, affected by material defects, surface coatings, and processing inconsistencies.
• Test Method Summary:
  • Prepare and align strips into a stack, maintaining proper orientation.
  • Measure the specimen using a standardized compression device and micrometer to determine the total stack thickness.
  • Calculate the lamination factor using specimen dimensions, mass, and material density.
• Precision: The standard highlights the importance of correctly aligned strips, uniform compression, and defect-free materials for accurate results. Variations in thickness or improper alignment can impact measurement bias.

Applications

• Quality Control of Magnetic Materials: Ensures amorphous strips meet quality benchmarks for use in magnetic cores, transformers, sensors, and electronic components.
• Design and Manufacturing: Assists manufacturers in selecting and verifying material for high-performance electromagnetic applications, where maximizing effective magnetic material content is critical.
• Material Selection and R&D: Supports engineers and researchers in evaluating and comparing amorphous magnetic strips for magnetic efficiency and reliability in advanced applications.
• Coil and Core Winding: Provides critical input to determine metal mass actually present in finished electromagnetic coils, enabling accurate performance predictions and improvements.
• Compliance and Trade: Ensures that products meet international standards, facilitating easier market entry and regulatory acceptance worldwide.

Related Standards

• ASTM A876 - Standard Specification for Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel
• ASTM A342/A342M - Standard Test Methods for Permeability of Feebly Magnetic Materials
• IEC 60404 Series - International standards for magnetic materials and their properties
• ISO 2864 - Continuous-cast magnetic steel strip

By following ASTM A900/A900M-01(2018), stakeholders in the electrical steel and magnetic materials industry benefit from a standardized, internationally recognized method for quantifying lamination factor. This enables improved product quality, better magnetic performance, and greater confidence in meeting global market and regulatory requirements.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: A900/A900M − 01 (Reapproved 2018)
Standard Test Method for
Lamination Factor of Amorphous Magnetic Strip
This standard is issued under the fixed designationA900/A900M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Significance and Use
1.1 This test method covers measurements of lamination 3.1 Lamination factor S indicates the deficiency of effective
factor (Note 1) of a specimen composed of strips cut from material volume which is due to the presence of oxides,
amorphous magnetic material. It is suitable for the determina- roughness, insulating coatings, and other conditions affecting
tion of lamination factor for thin, flat case, metallic strip the strip surface.
ranging in width from 0.25 to 8.00 in. [6.35 mm to 203 mm]
3.2 This test method is used to predict the fraction of metal
and in thickness from 0.0005 to 0.005 in. [12.7 to 127 µm].
that is included in the volume of the firm coil wound from the
specimen tape.
NOTE 1—Lamination factor is also termed space factor or stacking
factor.
4. Interferences
1.2 The values and equations stated in customary (egs-emu
4.1 This test method is predicated on correctly aligned test
and inch-pound) or SI units are to be regarded separately as
standard. Within this standard, SI units are shown in brackets. strips and uniform compression during test. Both of these
conditions are difficult to meet whenever the test specimens
Thevaluesstatedineachsystemmaynotbeexactequivalents;
therefore,eachsystemshallbeusedindependentlyoftheother. have one or more elevated ridges running lengthwise along the
surface of the strip.
Combining values from the two systems may result in noncon-
formance with this standard.
4.2 This test method also presupposes that the test speci-
1.3 This standard does not purport to address all of the mensarefreefromotherdefects,suchascamberandwaviness,
safety concerns, if any, associated with its use. It is the
that may affect the lamination factor.
responsibility of the user of this standard to establish appro-
5. Apparatus
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
5.1 Micrometers—Two types of micrometers are included
1.4 This international standard was developed in accor-
for use in this test method as follows:
dance with internationally recognized principles on standard-
5.1.1 Motor-Operated, Deadweight (Not Spring) Actuated
ization established in the Decision on Principles for the
Micrometer, conforming to the following requirements:
Development of International Standards, Guides and Recom-
5.1.1.1 The micrometer shall be a deadweight digital- or
mendations issued by the World Trade Organization Technical
dial-type micrometer, having two ground and lapped circular
Barriers to Trade (TBT) Committee.
surfaces with a capacity of not less than 0.030 in. [0.75 mm].
The movable face or presser foot shall have an area of 0.25 to
2 2
2. Summary of Test Method
0.33 in. [160 to 215 mm ] and corresponding to a diameter of
approximately 0.56 to 0.65 in. [14.2 to 16.5 mm]. The fixed
2.1 The laminated test specimen is oriented and aligned,
face or anvil shall be of such size that the whole area of the
then subjected to pressure in a compression device. The
presser foot is in contact with the anvil in the zero position.
resulting volume is then determined from the measured speci-
5.1.1.2 The surface shall be parallel to within 0.00005 in.
men height, width, and length. An equivalent solid volume is
[0.0012 mm] and the presser foot shall move on an axis
calculated from the specimen mass and the true density of the
perpendicular to the anvil.
specimen material. The ratio of the calculated (equivalent
5.1.1.3 The presser foot shall exert a steady pressure on the
solid) volume to the measured volume is the lamination factor.
specimen of 7.0 to 8.0 psi [48 to 55 kPa].
5.1.1.4 A digital readout is preferred. If an analog gauge is
used,thedialshallbeatleast2in.[51mm]indiameter.Itshall
This test method is under the jurisdiction of ASTM Committee A06 on
MagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTest
be continuously graduated to read directly to 0.0001 in.
Methods.
[0.0025 mm] and shall be required with a telltale hand, if
Current edition approved May 1, 2018. Published June 2018. Originally
necessary,recordingthenumberofcompleterevolutionsofthe
approved in 1991. Last previous edition approved in 2012 as A900/A900M–01
(2012). DOI: 10.1520/A0900_A0900M-01R18. large hand.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A900/A900M − 01 (2018)
7. Procedure
7.1 Select a representative segment from each sample of
material to be tested and cut the required number of strips as
FIG. 1 Ribbon Length for Lamination Factor Testing With Refer-
specified in 6.5 to a length as specified in 6.2.
ence Marks
7.2 Stack the test strips directly on top of one another in the
5.1.1.5 The micrometer shall be capable of repeating its
aligning fixture. Maintain the proper directionally as in Fig. 2.
readings to 0.00005 in. [0.0012 mm] at zero setting or on a
7.3 Align the edges of the strips and secure the stack by
steel gauge block.
clamping.
5.1.1.6 The deviations for the parts of the scale correspond-
7.4 Determine the maximum thickness of the specimen
ing to the specimen thickness measured shall be applied as
stack by making multiple measurements across the entire
corrections to the thickness reading.
width, at intervals slightly smaller than the presser foot of the
5.1.1.7 Theframeofthemicrometershallbeofsuchrigidity
micrometer
...