ASTM A901-03

Standard Specification for Amorphous Magnetic Core Alloys, Semi-Processed Types

ABSTRACT
This specification covers the general requirements to which flat-cast, amorphous, semi-processed, iron-base magnetic core alloys must conform. These alloys shall be produced by a rapid-quenching, direct-casting process, resulting in metals with noncrystalline structure. The metallic alloys shall be made to meet specified maximum core-loss values and shall be intended primarily for commercial power frequency applications in magnetic devices. Desirable core-loss and permeability characteristics shall be developed by further heat treatment in a magnetic field. Amorphous magnetic core alloys shall be composed principally of iron with small amounts of alloying elements such as boron and silicon. Other chemical elements shall be in residual amounts or can be added to improve fabrication or the physical or magnetic properties. The material shall conform to the required physical and mechanical properties such as density, ductility, thermal expansion, thermal conductivity, volume resistivity, lamination factor, surface, edge, and pinholes. The alloy shall also conform to the magnetic property requirements such as DC induction, DC coercive field strength, DC residual induction, core loss, and specific exciting power.
SCOPE
1.1 This specification covers the general requirements to which flat-cast, amorphous, semi-processed, iron-base magnetic core alloys must conform.
1.2 These alloys are produced by a rapid-quenching, direct-casting process, resulting in metals with noncrystalline structure. The metallic alloys are made to meet specified maximum core-loss values and are intended primarily for commercial power frequency (50- and 60-Hz) applications in magnetic devices. Desirable core-loss and permeability characteristics are developed by further heat treatment in a magnetic field by the purchaser. The heat treatment typically consists of heating the material to a temperature of 320 to 420°C in a dry, inert atmosphere for 5 to 10 min, although soak times of up to 2 h may be used for large transformer cores. A magnetic field may be required during annealing as designated by the producer. Exact optimum annealing conditions depend on the processing of the material and the size and shape of the device.
1.3 Some of these alloys are sensitive to mechanical stress. Care must be exercised in minimizing any stresses on the material in its final application, otherwise, its magnetic properties will be impaired significantly.
1.4 This specification is developed to aid in the purchase of transformer grade amorphous strip. It provides the chemical, physical, and magnetic parameters and procedures for quality control tests.
1.5 The values stated in customary (cgs-emu and inch-pound) units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units which are provided for information only and are not considered standard.
Note 1—For more information on procedures associated with this specification, refer to the following: Practices A 34/A 34M, A 664, A 700, and B 490; Test Methods A 370 and A 773.
1.6 This standard does not purport to address the safety concerns 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: 09-May-2003
• ICS: 29.030 - Magnetic materials
• ICS: 29.100.10 - Magnetic components
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.02 - Material Specifications

Relations

• Replaces: ASTM A901-97 - Standard Specification for Amorphous Magnetic Core Alloys, Semi-Processed Types
• Effective Date: 10-May-2003
• Replaced By: ASTM A901-03(2008) - Standard Specification for Amorphous Magnetic Core Alloys, Semi-Processed Types
• Effective Date: 01-Nov-2008
• Referred By: ASTM A932/A932M-01(2019) - Standard Test Method for Alternating-Current Magnetic Properties of Amorphous Materials at Power Frequencies Using Wattmeter-Ammeter-Voltmeter Method with Sheet Specimens
• Effective Date: 10-May-2003
• Referred By: ASTM A912/A912M-11(2019) - Standard Test Method for Alternating-Current Magnetic Properties of Amorphous Materials at Power Frequencies Using Wattmeter-Ammeter-Voltmeter Method with Toroidal Specimens
• Effective Date: 10-May-2003

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: A 901 – 03
Standard Specification for
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Amorphous Magnetic Core Alloys, Semi-Processed Types
This standard is issued under the fixed designation A 901; 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 (e) indicates an editorial change since the last revision or reapproval.
and B490; Test Methods A370 and A773.
1. Scope
1.1 This specification covers the general requirements to 1.6 This standard does not purport to address the safety
concerns associated with its use. It is the responsibility of the
which flat-cast, amorphous, semi-processed, iron-base mag-
netic core alloys must conform. user of this standard to establish appropriate safety and health
practices and determine the applicability of regulatory limita-
1.2 These alloys are produced by a rapid-quenching, direct-
casting process, resulting in metals with noncrystalline struc- tions prior to use.
ture. The metallic alloys are made to meet specified maximum
2. Referenced Documents
core-loss values and are intended primarily for commercial
2.1 ASTM Standards:
power frequency (50- and 60-Hz) applications in magnetic
A34/A34M Practice for Sampling and Procurement Test-
devices. Desirable core-loss and permeability characteristics
3
ing of Magnetic Materials
are developed by further heat treatment in a magnetic field by
2
A340 Terminology of Symbols and Definitions Relating to
the purchaser. The heat treatment typically consists of heating
3
Magnetic Testing
the material to a temperature of 320 to 420°C in a dry, inert
A370 TestMethodsandDefinitionsforMechanicalTesting
atmosphere for 5 to 10 min, although soak times of up to 2 h
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of Steel Products
may be used for large transformer cores.Amagnetic field may
A664 Practice for Identification of Standard Electrical
be required during annealing as designated by the producer.
3
Steel Grades in ASTM Specifications
Exact optimum annealing conditions depend on the processing
A700 Practices for Packaging, Marking, and Loading
of the material and the size and shape of the device.
5
Methods for Steel Products for Domestic Shipment
1.3 Some of these alloys are sensitive to mechanical stress.
A712 Test Method for Electrical Resistivity of Soft Mag-
Care must be exercised in minimizing any stresses on the
3
netic Alloys
material in its final application, otherwise, its magnetic prop-
A773 Test Method for dc Magnetic Properties of Materials
erties will be impaired significantly.
Using Ring and Permeameter Procedures with dc Elec-
1.4 This specification is developed to aid in the purchase of
3
tronic Hysteresigraphs
transformer grade amorphous strip. It provides the chemical,
A900 Test Method for Lamination Factor of Amorphous
physical, and magnetic parameters and procedures for quality
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Magnetic Strip
control tests.
B490 Practice for Micrometer Bend Test for Ductility of
1.5 The values stated in customary (cgs-emu and inch-
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Electrodeposits
pound) units are to be regarded as standard. The values given
7
C693 Test Method for Density of Glass by Buoyancy
in parentheses are mathematical conversions to SI units which
D3455 Test Methods for Compatibility of Construction
are provided for information only and are not considered
Materials with Electrical Insulating Oil of Petroleum
standard.
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Origin
NOTE 1—For more information on procedures associated with this
specification,refertothefollowing:PracticesA34/A34M,A664,A700,
3. Terminology
3.1 The terms and symbols used in this specification are
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This specification is under the jurisdiction of ASTM Committee A06 on defined in Terminology A340.
Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on
Material Specifications.
Current edition approved May 10, 2003. Published June 2003. Originally
approved in 1990. Last previous edition approved in 1997 as A901–97.
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Theprocessofheattreatmentinamagneticfieldiscoveredbyapatentheldby Annual Book of ASTM Standards, Vol 03.04.
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General Electric Co. Interested parties are invited to submit information regarding Annual Book of ASTM Standards, Vol 01.03.
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the identification of acceptable alternatives to this patented item to the Committee Annual Book of ASTM Standards, Vol 01.05.
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on Standards, ASTM International Headquarters. Your comments will receive Annual Book of ASTM Standards, Vol 02.05.
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careful consideration at a meeting of the responsible technical committee, which Annual Book of ASTM Standards, Vol 15.02.
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you may attend. Annual Book of ASTM Standards, Vol 10.03.
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A 901–03
4. Dimensions 7.6 Lamin
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