ASTM A901-19 - 1.8.2019
 
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 (amorphous) 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 user. 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 significantly impaired.

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 SI units are to be regarded as standard. The values given in parentheses are numerical conversions to customary (cgs and inch-pound) units which are provided for information only and are not considered standard.

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, 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

A340-23a

Standard Terminology of Symbols and Definitions Relating to Magnetic Testing (Includes all amendments and changes 12/19/2023).

A370-26

Standard Test Methods and Definitions for Mechanical Testing of Steel Products

A900/A900M-24

Standard Test Method for Lamination Factor of Amorphous Magnetic Strip

B490-09(2026)

Standard Practice for Micrometer Bend Test for Ductility of Electrodeposits

C693-24

Standard Test Method for Density of Glass by Buoyancy

D3455-11(2019)

Standard Test Methods for Compatibility of Construction Material with Electrical Insulating Oil of Petroleum Origin

A700-14(2019)

Standard Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment

A712-14(2022)

Standard Test Method for Electrical Resistivity of Soft Magnetic Alloys

A773/A773M-21

Standard Test Method for Direct Current Magnetic Properties of Low Coercivity Magnetic Materials Using Hysteresigraphs

A664-15(2022)

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

A34/A34M-06(2021)

Standard Practice for Sampling and Procurement Testing of Magnetic Materials