ASTM A901-03(2008)
(Specification)Standard Specification for Amorphous Magnetic Core Alloys, Semi-Processed Types
Standard Specification for Amorphous Magnetic Core Alloys, Semi-Processed Types
ABSTRACT
This specification covers the 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 alloys shall be made to meet specified maximum core-loss values and shall be intended primarily for commercial power frequency applications. Desirable core-loss and permeability characteristics shall be developed by further heat treatment in a magnetic field. Amorphous magnetic core alloys are normally composed of iron with small amounts of alloying elements such as boron and silicon. There are no specific chemical requirements in this specification. Material produced to this specification 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/A 773M.
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
Relations
Buy Standard
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: A901 – 03 (Reapproved 2008)
Standard Specification for
Amorphous Magnetic Core Alloys, Semi-Processed Types
This standard is issued under the fixed designation A901; 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.
and B490; Test Methods A370 and A773/A773M.
1. Scope
1.6 This standard does not purport to address the safety
1.1 This specification covers the general requirements to
which flat-cast, amorphous, semi-processed, iron-base mag- concerns associated with its use. It is the responsibility of the
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 Testing
devices. Desirable core-loss and permeability characteristics
of Magnetic Materials
are developed by further heat treatment in a magnetic field by
A340 Terminology of Symbols and Definitions Relating to
the purchaser. The heat treatment typically consists of heating
Magnetic Testing
the material to a temperature of 320 to 420°C in a dry, inert
A370 Test Methods and Definitions for Mechanical Testing
atmosphere for 5 to 10 min, although soak times of up to 2 h
of Steel Products
may be used for large transformer cores.Amagnetic field may
A664 PracticeforIdentificationofStandardElectricalSteel
be required during annealing as designated by the producer.
Grades in ASTM Specifications
Exact optimum annealing conditions depend on the processing
A700 PracticesforPackaging,Marking,andLoadingMeth-
of the material and the size and shape of the device.
ods for Steel Products for 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
netic Alloys
material in its final application, otherwise, its magnetic prop-
A773/A773M Test Method for dc Magnetic Properties of
erties will be impaired significantly.
Materials Using Ring and Permeameter Procedures with
1.4 This specification is developed to aid in the purchase of
dc Electronic Hysteresigraphs
transformer grade amorphous strip. It provides the chemical,
A900/A900M Test Method for Lamination Factor ofAmor-
physical, and magnetic parameters and procedures for quality
phous Magnetic Strip
control tests.
B490 Practice for Micrometer Bend Test for Ductility of
1.5 The values stated in customary (cgs-emu and inch-
Electrodeposits
pound) units are to be regarded as standard. The values given
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
MaterialwithElectricalInsulatingOilofPetroleumOrigin
standard.
NOTE 1—For more information on procedures associated with this
3. Terminology
specification, refer to the following: Practices A34/A34M, A664, A700,
3.1 The terms and symbols used in this specification are
defined in Terminology A340.
This specification is under the jurisdiction of ASTM Committee A06 on
4. Dimensions
Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on
Material Specifications.
4.1 Width—Tolerances on nominal as-cast strip shall be
Current edition approved Nov. 1, 2008. Published December 2008. Originally
+0.004, −0.020 in. (+0.1 mm, −0.5 mm) from specified
approved in 1990. Last previous edition approved in 2003 as A901–03. DOI:
purchase width.
10.1520/A0901-03R08.
Theprocessofheattreatmentinamagneticfieldiscoveredbyapatentheldby
General Electric Co. Interested parties are invited to submit information regarding
the identification of acceptable alternatives to this patented item to the Committee For referenced ASTM standards, visit the ASTM website, www.astm.org, or
on Standards, ASTM International Headquarters. Your comments will receive contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
careful consideration at a meeting of the responsible technical committee, which Standards volume information, refer to the standard’s Document Summary page on
you may attend. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A901 – 03 (2008)
4.2 Thickness—The nominal thickness shall be 0.001 in. 7.7 Surface—The strip surface and edges shall have no
(0.025 mm) as measured by a 0.25-in. (6.35-mm) diameter wrinkles, dimples, cracks, folds, flakes, or other injurious
anvil micrometer. The nominal thickness may vary 60.0002 imperfections that would make the material unsuitable for the
in. (60.005 mm), but the maximum thickness variation across fabrication of transformer cores.
the width shall be within 610% of the mean thickness, or as
7.8 Edge—The strip edge shall have no slivers with a
agreed upon between the purchaser and the producer.
maximum dimension exceeding 0.004 in. (0.1 mm).
7.9 Camber—Thestripedgeshallshownoexcessivelateral
5. Material Requirements
curvature(camber).Maximumdeviationfromastraightlineof
5.1 Amorphous magnetic core alloys are composed princi-
an 8-ft (2.4-m) strip edge shall not exceed 0.1 in. (2.5 mm).
pally of iron with small amounts of alloying elements such as
7.10 Pinholes—The strip shall have no pinholes exceeding
boron and silicon. Other chemical elements are in residual
0.08 in. (2.0 mm). Maximum hole frequency, visible against a
amountsorcanbeaddedtoimprovefabricationorthephysical
2 −4
light source, shall not be more than 1 per 3 in. (19.4 310
ormagneticproperties.Theproducershallprovide,onrequest,
m ).
a statement of the nominal chemistry being supplied. The
nominal composition for one particular alloy, in weight per-
8. Magnetic Property Requirements
cent, is: iron 92, silicon 5, and boron 3.
8.1 Test Procedure—The magnetic quality of each batch of
6. Sampling
material (as defined in 6.1) shall be determined by obtaining
test samples from both ends of a batch (or lot). These samples
6.1 Acontinuously cast strip in one coil without breaks will
shall be annealed in a dry, inert atmosphere with an applied
constituteonetestlot.Inpractice,thismayrepresentquantities
up to 2200 lb (1000 kg), depending on the width of the strip. magnetic field of at least 10 Oe (800A/m) using the time and
temperature sequence recommended by the producer. The
6.2 Test samples normally shall be taken from both ends of
the continuous strip of each test lot. Other sample frequencies samples may be either in toroidal or flat strip form as agreed
upon between the producer and the purchaser.
maybeusedasagreeduponbytheproducerandthepurchaser.
6.3 For small coils, less than 100 lb (45 kg), and for coils
8.2 Amorphous magnetic core alloys are purchased to
containing splices, the test lot shall be as agreed upon between
specified maximum core loss requirements. The purchaser
the producer and the purchaser.
shallmakecleartotheproducerthelimitingvaluesofcoreloss
requiredfortheorderedmaterial.Forthenominalcomposition
7. Physical and Mechanical Property Requireme
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:A 901–97 Designation: A 901 – 03 (Reapproved 2008)
Standard Specification for
Amorphous Magnetic Core Alloys, Semi-Processed Types
This standard is issued under the fixed designation A901; 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
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-and60-Hz)applicationsinmagneticdevices.Desirablecore-lossandpermeabilitycharacteristicsaredevelopedby
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.
1.5The values stated in either customary (cgs-emu and inch-pound) units or SI units are to be regarded separately as standard.
Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each
system shall be used independently of the other. Combining values from the two systems may result in nonconformance with this
specification.
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 A34, A664, A700, and
B490A34/A34M, A664, A700, and B490; Test Methods A370 and A773 and A773/A773M.
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.
2. Referenced Documents
2.1 ASTM Standards:
A3434/A34M Practice for Sampling and Procurement Testing of Magnetic Materials
A340 Terminology of Symbols and Definitions Relating to Magnetic Testing
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A664 Practice for Identification of Standard Electrical- and Lamination- Electrical Steel Grades in ASTM Specifications
A700 Practices for Packaging, Marking, and Loading Methods for Steel Products for Domestic Shipment
A712 Test Method for Electrical Resistivity of Soft Magnetic Alloys
A773/A773M TestMethodforD-CdcMagneticPropertiesofMaterialsUsingRingandPermeameterProcedureswithD-Cdc
Electronic Hysteresigraphs
A900/A900M Test Method for Lamination Factor of Amorphous Magnetic Strip
This specification is under the jurisdiction of ASTM Committee A-6A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on Material
Specifications.
CurrenteditionapprovedJune10,1997.Nov.1,2008.PublishedDecember1997.2008.OriginallypublishedasA901–90.approvedin1990.Lastpreviouseditionapproved
in 2003 as A901–903.
The process of heat treatment in a magnetic field is covered by a patent held by General Electric Co. Interested parties are invited to submit information regarding the
identification of acceptable alternatives to this patented item to the Committee on Standards, ASTM International Headquarters. Your comments will receive careful
consideration at a meeting of the responsible technical committee, which you may attend.
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.ForAnnualBookofASTMStandards
, Vol 03.04.volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A 901 – 03 (2008)
B490 Practice for Micrometer Bend Test for Ductility of Electrodeposits
C693 Test Method for Density of Glass by Buoyancy
D3455 Test Methods for Compatibility of Construction MaterialsMaterial with Electrical Insulating Oil of Petroleum Origin
3. Terminology
3.1 The terms and symbols used in this specification are defined in Terminology A340.
4. Dimensions
4.1 Width—Tolerances on nominal as-cast strip shall be +0.004, −0.020 in. [+0.1(+0.1 mm, −0.5 mm]mm) from specified
purchase width.
4.2 Thickness—The nominal thickness shall be 0.001 in. [0.025 mm](0.025 mm) as measured by a 0.25-in. [6.35-mm](6.35-
mm) diameter anvil micrometer. The nominal thickness may vary 60.0002 in. [60.005 mm],(60.005 mm), but the maximum
thickness variation across the width shall be within 610% of the mean thickness, or as agreed upon between the purchaser and
the producer.
5. Material Requirements
5.1 Amorphous magnetic core alloys are composed principally of iron with small amounts of alloying elements such as boron
and silicon. Other chemical elements are in residual amounts or can be added to improve fabrication or the physical or magnetic
properties.Theproducershallprovide,onrequest,astatementofthenominalchemistrybeingsupplied.Thenominalcomposition
for one particular alloy, in weight percent, is: iron 92, silicon 5, and boron 3.
6. Sampling
6.1 Acontinuously cast strip in one coil without breaks will constitute one test lot. In practice, this may represent quantities up
to 2200 lb [1000 kg],(1000 kg), depending on the width of the strip.
6.2 Test samples normally shall be taken from both ends of the continuous strip of each test lot. Other sample frequencies may
be used as agreed upon by the producer and the purchaser.
6.3 Forsmallcoils,lessthan100lb[45kg],(45kg),andforcoilscontainingsplices,thetestlotshallbeasagreeduponbetween
the producer and the purchaser.
7. Physical and Mechanical Property Requirements
3 (650 kg/m
7.1 Density—The density shall be provided by the producer to a precision of 60.05 g/cm [650 kg/m ]) as measured
by Test Method C693.
7.2 Ductility—Strip bend ductility, with free solidification surface facing inward, shall be such that a minimum 1-m length of
ribbon may be passed 180° around a 0.125-in. [3-mm](3-mm) polished steel rod without cracking or fracture.
7.3 ThermalExpansion—Thenominalcoefficientofthermalexpansionshallbereportedforthetemperaturerange40to400°C.
7.4 Thermal Conductivity—The nominal value measured across the width shall be reported for temperatures of 25, 100, and
400°C. The defined thermal conductivity of the material shall not differ from the reported value by more than 620%.
7.5 Volume Resistivity—The nominal volume resistivity shall be reported as measured by Test Method A712.
7.6 Lamination Factor—The minimum lamination factor of uncoated material shall be 77% as measured in accordance with
Test MethodA900/A900M.The lamination factor for coated material shall be as agreed between the producer and the purchaser.
7.7 Surface—Thestripsurfaceandedgesshallhavenowrinkles,dimples,cracks,folds,flakes,orotherinjuriousimperfections
that would make the material unsuitable for the fabrication of transformer cores.
7.8 Edge—The strip edge shall have no slivers with a maximum dimension exceeding 0.004 in.
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.