ASTM A664-15(2022)

Standard Practice for Identification of Standard Electrical Steel Grades in ASTM Specifications

ABSTRACT
This practice explains the procedure for identifying standard grades and types of flat-rolled electrical steels in ASTM electrical steel specifications. This practice applies to flat-rolled magnetically soft irons and steel such as low-carbon steels and alloys of iron with silicon, aluminum, and so forth produced to a specified thickness and maximum value of core loss. These designations are intended to replace the old AISI M designations which are no longer supported. The practice also has a cross-reference between thickness and electrical sheet gage number.
SCOPE
1.1 This practice covers the procedure for designating (within ASTM specifications) standard grades of flat-rolled electrical steels made to specified maximum values of specific core loss. This practice applies to magnetically soft irons and steel (low-carbon steels and alloys of iron with silicon, aluminum, and other alloying elements) where a core loss measurement at a stated peak value of alternating induction and a stated frequency, such as 1.5 T (15 kG) and 60 Hz, is normally used to grade the material. This practice also applies when some other property is specified (or a different induction or frequency, or both) as the limiting characteristic, provided the material also meets all the requirements of the ASTM specification.  
1.2 Individual specifications that are in conformity with this practice are Specifications A677, A683, A726, A876, and A1086.  
1.3 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.  
1.4 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.  
1.5 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-Jun-2022
• ICS: 77.080.20 - Steels
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.02 - Material Specifications

Relations

• Refers: ASTM A340-23a - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Dec-2023
• Refers: ASTM A683-16(2023) - Standard Specification for Nonoriented Electrical Steel, Semiprocessed Types
• Effective Date: 01-Dec-2023
• Refers: ASTM A677-16(2023) - Standard Specification for Nonoriented Electrical Steel Fully Processed Types
• Effective Date: 01-Dec-2023
• Refers: ASTM A340-19b - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Oct-2019
• Refers: ASTM A340-19a - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Jun-2019
• Refers: ASTM A340-19 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Feb-2019
• Refers: ASTM A976-18 - Standard Classification of Insulating Coatings for Electrical Steels by Composition, Relative Insulating Ability and Application
• Effective Date: 01-Oct-2018
• Refers: ASTM A340-18 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Jun-2018
• Refers: ASTM A340-17a - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Oct-2017
• Refers: ASTM A340-17 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Jul-2017
• Refers: ASTM A876-17 - Standard Specification for Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types
• Effective Date: 01-Apr-2017
• Refers: ASTM A340-16e1 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-May-2016
• Refers: ASTM A340-16 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-May-2016
• Refers: ASTM A340-15 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Oct-2015
• Refers: ASTM A340-14 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Oct-2014

Overview

ASTM A664-15(2022): Standard Practice for Identification of Standard Electrical Steel Grades in ASTM Specifications provides a unified procedure for designating grades and types of flat-rolled electrical steels. This standard supports the identification and ordering of electrical steels, including magnetically soft irons and steel such as low-carbon steels and iron alloys with silicon or aluminum. Its designation system clarifies the properties of materials produced to specified thicknesses and maximum core loss values. ASTM A664 is recognized internationally, replacing the outdated AISI M designations and aligning with global technical barriers to trade.

Key Topics

• Electrical Steel Grade Designation: Defines a six-character format (e.g., 35H094) where digits represent thickness (in millimeters) and reference core loss, while code letters specify material category and testing conditions.
• Material Scope: Applies to flat-rolled magnetically soft steels, including low-carbon and silicon-aluminum alloys, processed for controlled electromagnetic properties.
• Core Loss as a Grading Basis: Evaluates and standardizes materials based on specific core loss (in W/kg or W/lb) at defined magnetic induction and frequency, such as 1.5 T at 60 Hz.
• Cross-Reference with Electrical Sheet Gage: Provides tables relating nominal thickness to electrical sheet gauge numbers, facilitating transition from legacy gage systems.
• Usage in ASTM Specifications: Ensures consistency in grade identification within ASTM’s suite of electrical steel standards (such as A677, A683, A726, A876, and A1086).
• Use of SI Units: Stipulates SI units as standard, with customary units provided for reference only.
• Insulating Coatings: Allows integration with insulating coating classification (ASTM A976) for enhanced traceability and data management.

Applications

ASTM A664-15(2022) is highly relevant for industries manufacturing or specifying electrical steels for critical electrical apparatus, including:

• Transformers: Accurate grade designation ensures core materials meet efficiency and loss requirements.
• Motors and Generators: Reliable identification of steel types optimizes design for performance and energy efficiency.
• Magnetic Lamination Steel: Facilitates selection for applications needing controlled electromagnetic properties with low core loss.
• Electrical Sheet Suppliers: Allows steel producers and suppliers to communicate material properties consistently with customers and regulatory bodies.
• Database Integration: Harmonized alphanumeric identifiers support digital inventory and quality control systems.

Related Standards

For comprehensive material specification and testing, ASTM A664-15(2022) should be used alongside related ASTM standards:

• ASTM A677: Specification for Nonoriented Electrical Steel, Fully Processed Types
• ASTM A683: Specification for Nonoriented Electrical Steel, Semiprocessed Types
• ASTM A726: Specification for Cold-Rolled Magnetic Lamination Steel, Semiprocessed Types
• ASTM A876: Specification for Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types
• ASTM A1086: Specification for Thin-Gauge Nonoriented Electrical Steel, Fully Processed Types
• ASTM A976: Classification of Insulating Coatings for Electrical Steels

Practical Value

• Establishes a common language for specifying and identifying electrical steel grades globally
• Reduces confusion and errors caused by legacy designation systems
• Streamlines procurement, specification, and quality assurance processes in electrical manufacturing
• Enables compliance with international trade and regulatory requirements

Keywords: ASTM A664, electrical steel, grade designation, core loss, magnetically soft steel, silicon steel, ASTM specifications, transformer steel, magnetic lamination, standard identification.

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:A664 −15 (Reapproved 2022)
Standard Practice for
Identification of Standard Electrical Steel Grades in ASTM
Specifications
This standard is issued under the fixed designation A664; 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 2. Referenced Documents
2.1 ASTM Standards:
1.1 This practice covers the procedure for designating
A340 Terminology of Symbols and Definitions Relating to
(within ASTM specifications) standard grades of flat-rolled
Magnetic Testing
electrical steels made to specified maximum values of specific
A677 Specification for Nonoriented Electrical Steel Fully
core loss. This practice applies to magnetically soft irons and
Processed Types
steel (low-carbon steels and alloys of iron with silicon,
A683 Specification for Nonoriented Electrical Steel, Semi-
aluminum, and other alloying elements) where a core loss
processed Types
measurementatastatedpeakvalueofalternatinginductionand
A726 Specification for Cold-Rolled Magnetic Lamination
a stated frequency, such as 1.5 T (15 kG) and 60 Hz, is
Quality Steel, Semiprocessed Types
normally used to grade the material. This practice also applies
A876 Specification for Flat-Rolled, Grain-Oriented, Silicon-
when some other property is specified (or a different induction
Iron, Electrical Steel, Fully Processed Types
or frequency, or both) as the limiting characteristic, provided
A976 Classification of Insulating Coatings for Electrical
the material also meets all the requirements of the ASTM
Steels by Composition, Relative Insulating Ability and
specification.
Application
1.2 Individual specifications that are in conformity with this
A1086 Specification for Thin-Gauge Nonoriented Electrical
practice are Specifications A677, A683, A726, A876, and
Steel Fully Processed Types
A1086.
3. Terminology
1.3 The values stated in SI units are to be regarded as
3.1 The terms and symbols used in this practice are defined
standard. The values given in parentheses are mathematical
in Terminology A340.
conversions to customary (cgs-emu and inch-pound) units
whichareprovidedforinformationonlyandarenotconsidered
4. Procedure
standard.
4.1 General Requirements of the Core-Loss-Type
1.4 This standard does not purport to address all of the
Designations—The core-loss-type designations to be used for
safety concerns, if any, associated with its use. It is the
ordering purposes and for identification of the shipped material
responsibility of the user of this standard to establish appro-
in ASTM specifications for electrical steels shall follow a
priate safety, health, and environmental practices and deter-
six-character protocol (for example, 35H094) comprised of the
mine the applicability of regulatory limitations prior to use.
elements described in 4.2, 4.3, and 4.4:
1.5 This international standard was developed in accor-
4.2 First Two Digits—The first two digits of the grade
dance with internationally recognized principles on standard-
designation shall represent the nominal thickness of the mate-
ization established in the Decision on Principles for the
rial in millimetres to the nearest one hundredth millimetre
Development of International Standards, Guides and Recom-
multiplied by 100. For instance, the number 36 represents a
mendations issued by the World Trade Organization Technical
thickness of 0.36 mm (0.014 in.).
Barriers to Trade (TBT) Committee.
4.2.1 Designation of nominal thickness by Electrical Sheet
Gauge Number does not conform to the requirements of this
practice or of specifications referred to herein. Refer to
This practice is under the jurisdiction of ASTM Committee A06 on Magnetic
Properties and is the direct responsibility of Subcommittee A06.02 on Material
Specifications. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved July 1, 2022. Published July 2022. Originally approved contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
in 1972. Last previous edition approved in 2015 as A664 – 15. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
A0664-15R22. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A664−15 (2022)
Appendix X1 for the relationship between Electrical Sheet 4.4.1 Examples of Three Digit Grade Designations:
Gauge Number and nominal thickness in millimetres and
4.4.1.1 Example1—The 155 designation in anASTM speci-
inches.
fication used in conjunction with the Code Letter F represents
material with a maximum specific core loss value of 3.42W/kg
4.3 Code Letters—A code letter shall designate the general
(1.55 W/lb) determined at 1.5 T (15 kG) and 60 Hz on an
category of magnetic material and the standard sampling and
as-sheared Epstein specimen consisting of one half of the strips
testing practices that apply. The precise conditions of sampling
cut parallel to the rolling direction and the other half cut
and testing are given in theASTM specification covering each
perpendicular to the rolling direction. The three digit designa-
class of material. The code letter to be used and the sampling
tion 155 is based on the reference value of 1.55 W/lb for the
and testing conditions associated with that letter shall be as in
maximum value of specific core loss.
Table 1.
4.4.1.2 Example2—The 094 designation in anASTM speci-
4.4 Last Three Digits—The last three digits of the grade
fication used in conjunction with the Code Letter H represents
designation provide a reference to the general specific core loss
material with a maximum specific core loss value of 2.07W/kg
values and testing conditions of the material. These digits are
(0.940 W/lb) determined at 1.7 T (17 kG) and 60 Hz on a
based on the reference value for maximum permissible specific
parallel grain Epstein specimen annealed after shearing. The
core loss in W/lb corresponding to the standardized acceptance
three digit designation 094 is based on the reference value of
value in W/kg. The three digit designation presents the
0.940 W/lb for the maximum value of specific core loss.
reference value in watt per pound, at the test conditions
indicated by the code letter, to the nearest one-hundredth watt 4.4.1.3 Example3—The 650 designation in anASTM speci-
per pound multiplied by 100. Examples of the use of the three fication used in conjunction with the Code Letter T represents
digit code with selected Code Letters are presented in 4.4.1. material with a maximum specific core loss value of 14.3W/kg
TABLE 1 Code Letters and Sampling and Testing Conditions
Code Letter ASTM Specification Class of Material and Core-Loss Testing Conditions
D A726 Magnetic lamination steel, semiprocessed, with specific core-loss value deter-
A
mined in W/kg at 1.5 T (15 kG) and 60 Hz on Epstein specimens after a quality
development anneal at 790 °C (1450 °F) with a 1-h soak period. The three digit
grade designation is based on the specific cor
...