ASTM A726-18
(Specification)Standard Specification for Cold-Rolled Magnetic Lamination Quality Steel, Semiprocessed Types
Standard Specification for Cold-Rolled Magnetic Lamination Quality Steel, Semiprocessed Types
ABSTRACT
This specification covers the standard requirements for semi-processed cold-rolled magnetic lamination quality steels. These steels shall be made by the basic-oxygen or electric-furnace method and shall be processed by hot rolling, pickling, cold rolling, annealing, and temper rolling. Magnetic lamination steels shall have low-carbon contents and may have manganese, phosphorus, silicon, and aluminum additions to enhance punchability and to improve magnetic characteristics by increasing the electrical resistivity. There are no fixed chemical requirements for these steels only the requirement to meet the specified magnetic properties. These steels must be heat treated by the user to develop the specified magnetic properties. This specification covered steels with thicknesses of 0.0185 in. ( 0.47 mm), 0.022 in. (0.56 mm), 0.025 in. (0.64 mm), 0.028 in. (0.71 mm) and 0.031 in. (0.79 mm). For a given thickness there are three or more core loss types distinguished by maximum allowable core loss after a specified quality development anneal. Magnetic testing shall be done after the specified quality development anneal and shall use the Epstein test method. Magnetic testing shall be done at a test frequency of 60 Hz and a maximum flux density of 15 kG (1.5 T). Test methods to determine the magnetic and mechanical properties are listed. Other typical magnetic and physical properties are listed for reference.
SCOPE
1.1 This specification covers cold-rolled carbon sheet steel used for magnetic applications. These products, commonly called “cold-rolled magnetic lamination steel” (CRML) are usually intended for applications in which the stamped laminations or assembled core structures for electrical equipment are annealed to develop the desired core loss and permeability characteristics.
1.2 This steel is produced to maximum specific core-loss values and is intended primarily for commercial power frequency (50- and 60-Hz) applications in magnetic devices. Specific core-loss and permeability characteristics in conformance with this specification are developed through heat treatment by the user.
1.3 Non-guaranteed core-loss types, usually made to controlled chemical compositions, are available but are not covered by this specification.
1.4 Higher quality core-loss types are low carbon, silicon-iron, or silicon-aluminum-iron alloys containing up to about 2.5 % silicon and less than 1 % aluminum. These steels are usually given a critical reduction on a temper-mill to yield specified magnetic properties after a suitable lamination anneal. These products, typically called semiprocessed magnetic lamination steel, are classified by the ASTM Code Letter D in accordance with Practice A664.
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to customary (cgs-emu and inch-pound) units which are provided for information only and are not considered standard.
1.6 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.
1.7 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.
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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:A726 −18
Standard Specification for
Cold-Rolled Magnetic Lamination Quality Steel,
1
Semiprocessed Types
This standard is issued under the fixed designation A726; 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 1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This specification covers cold-rolled carbon sheet steel
ization established in the Decision on Principles for the
used for magnetic applications. These products, commonly
Development of International Standards, Guides and Recom-
called “cold-rolled magnetic lamination steel” (CRML) are
mendations issued by the World Trade Organization Technical
usually intended for applications in which the stamped lami-
Barriers to Trade (TBT) Committee.
nations or assembled core structures for electrical equipment
are annealed to develop the desired core loss and permeability
2. Referenced Documents
characteristics.
2
2.1 ASTM Standards:
1.2 This steel is produced to maximum specific core-loss
A34/A34MPractice for Sampling and Procurement Testing
values and is intended primarily for commercial power fre-
of Magnetic Materials
quency (50- and 60-Hz) applications in magnetic devices.
A340Terminology of Symbols and Definitions Relating to
Specific core-loss and permeability characteristics in confor-
Magnetic Testing
mance with this specification are developed through heat
A343/A343MTest Method for Alternating-Current Mag-
treatment by the user.
netic Properties of Materials at Power Frequencies Using
1.3 Non-guaranteed core-loss types, usually made to con-
Wattmeter-Ammeter-Voltmeter Method and 25-cm Ep-
trolled chemical compositions, are available but are not cov-
stein Test Frame
ered by this specification.
A370Test Methods and Definitions for Mechanical Testing
of Steel Products
1.4 Higher quality core-loss types are low carbon, silicon-
A664Practice for Identification of Standard Electrical Steel
iron, or silicon-aluminum-iron alloys containing up to about
Grades in ASTM Specifications
2.5% silicon and less than 1% aluminum. These steels are
usually given a critical reduction on a temper-mill to yield A700Guide for Packaging, Marking, and Loading Methods
for Steel Products for Shipment
specified magnetic properties after a suitable lamination an-
neal. These products, typically called semiprocessed magnetic A717/A717MTestMethodforSurfaceInsulationResistivity
of Single-Strip Specimens
lamination steel, are classified by theASTM Code Letter D in
accordance with Practice A664. A937/A937MTest Method for Determining Interlaminar
Resistance of Insulating Coatings Using Two Adjacent
1.5 The values stated in SI units are to be regarded as
Test Surfaces
standard. The values given in parentheses are mathematical
A976Classification of Insulating Coatings for Electrical
conversions to customary (cgs-emu and inch-pound) units
Steels by Composition, Relative Insulating Ability and
whichareprovidedforinformationonlyandarenotconsidered
Application
standard.
E18Test Methods for Rockwell Hardness of Metallic Ma-
1.6 This standard does not purport to address all of the
terials
safety concerns, if any, associated with its use. It is the
E140Hardness Conversion Tables for Metals Relationship
responsibility of the user of this standard to establish appro-
Among Brinell Hardness, Vickers Hardness, Rockwell
priate safety, health, and environmental practices and deter-
Hardness, Superficial Hardness, Knoop Hardness, Sclero-
mine the applicability of regulatory limitations prior to use.
scope Hardness, and Leeb Hardness
1
This specification is under the jurisdiction of ASTM Committee A06 on
Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on
2
Material Specifications. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2018. Published October 2018. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1976. Last previous edition approved in 2010 as A726–05 (2010). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/A0726-18. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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A726−18
3. Terminology 5.1.1 ASTM specification number and date of issue.
5.1.2
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM 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: A726 − 05 (Reapproved 2010) A726 − 18
Standard Specification for
Cold-Rolled Magnetic Lamination Quality Steel,
1
Semiprocessed Types
This standard is issued under the fixed designation A726; 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
1.1 This specification covers cold-rolled carbon sheet steel used for magnetic applications. These products, commonly called
“cold-rolled magnetic lamination steel” (CRML) are usually intended for applications in which the stamped laminations or
assembled core structures for electrical equipment are annealed to develop the desired core loss and permeability characteristics.
1.2 By using appropriate lamination annealing practices, the user can optimize magnetic properties for the various types.This
steel is produced to maximum specific core-loss values and is intended primarily for commercial power frequency (50- and 60-Hz)
applications in magnetic devices. Specific core-loss and permeability characteristics in conformance with this specification are
developed through heat treatment by the user.
1.3 Non-guaranteed core-loss types, usually made to controlled chemical compositions, are available but are not covered by this
specification.
1.4 Higher quality core-loss types are made to controlled chemical compositions and low carbon, silicon-iron, or silicon-
aluminum-iron alloys containing up to about 2.5 % silicon and less than 1 % aluminum. These steels are usually given a critical
reduction on a temper-mill to yield specified magnetic properties after a suitable lamination anneal. These products, typically called
semiprocessed magnetic lamination steel, are classified by the ASTM Code Letter D in accordance with Practice A664.
1.5 The values stated in customary (cgs-emu and inch-pound) SI units are to be regarded as standard. The values given in
parentheses are mathematical conversions to SI customary (cgs-emu and inch-pound) units which are provided for information
only and are not considered standard.
1.6 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.
1.7 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.
2. Referenced Documents
2
2.1 ASTM Standards:
A34/A34M Practice for Sampling and Procurement Testing of Magnetic Materials
A340 Terminology of Symbols and Definitions Relating to Magnetic Testing
A343/A343M Test Method for Alternating-Current Magnetic Properties of Materials at Power Frequencies Using Wattmeter-
Ammeter-Voltmeter Method and 25-cm Epstein Test Frame
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A664 Practice for Identification of Standard Electrical Steel Grades in ASTM Specifications
A700 Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment
A717/A717M Test Method for Surface Insulation Resistivity of Single-Strip Specimens
A937/A937M Test Method for Determining Interlaminar Resistance of Insulating Coatings Using Two Adjacent Test Surfaces
1
This specification is under the jurisdiction of ASTM Committee A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on Material
Specifications.
Current edition approved Nov. 1, 2010Oct. 1, 2018. Published December 2010October 2018. Originally approved in 1976. Last previous edition approved in 20052010
as A726 – 05.A726 – 05 (2010). DOI: 10.1520/A0726-05R10.10.1520/A0726-18.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
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
1
---------------------- Page: 1 ----------------------
A726 − 18
A976 Classification of Insulating
...
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