Overview
IEC 60404-13:2018 is an international standard published by the International Electrotechnical Commission (IEC) that defines methods for measuring physical properties of electrical steel strip and sheet, specifically focusing on resistivity, density, and stacking factor. These properties are critical for characterizing both grain-oriented and non-oriented electrical steels used extensively in electrical applications such as transformers, motors, and generators. The standard ensures consistent and accurate determination of these key parameters under controlled ambient conditions (23 ±5 °C), critical for evaluating material performance and quality.
This second edition revises procedures to improve measurement accuracy and applicability, including new methods like the van-der-Pauw method for resistivity (applicable to Epstein strip specimens) and the introduction of the gas pyknometer method for density measurement. It also updates requirements for stacking factor testing and provides informative annexes with practical examples and apparatus designs to facilitate standardized implementation.
Key Topics
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Resistivity Measurement (Section 4):
Two main methods are specified:
- Method R1: Resistance measurement using Epstein strip specimens.
- Method R2: Van-der-Pauw method using rectangular sheet specimens, now also applicable to strip specimens.
The section addresses specimen preparation, apparatus requirements, measurement procedure, repeatability, and reproducibility to ensure precise resistivity determination.
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Density Measurement (Section 5):
Multiple methods covered include:
- Resistance-based density measurement (Method D1).
- Gas pyknometer method (Method D2), newly introduced to enhance accuracy.
- Liquid immersion method and calculation based on chemical composition (silicon and aluminum content), quoted for reference.
Methods ensure density determination critical for accurate calculation of magnetic polarization and resistivity values.
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Stacking Factor Determination (Section 6):
Defines procedures to measure the stacking factor of electrical steel laminations, a key parameter affecting magnetic performance. Updated tolerances for specimen dimensions and improved repeatability criteria are included. Measurement practices and reporting are standardized to support consistent results.
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Informative Annexes:
- Annex A details an example apparatus for resistivity measurement using a rectangular specimen.
- Annex B describes an example for density determination using the gas pyknometer.
- Annex C provides guidance for density calculation based on elemental composition.
Applications
IEC 60404-13:2018 applies primarily to manufacturers, testing laboratories, and quality control engineers involved with electrical steel strip and sheet production and evaluation. The standard’s methodologies support:
- Quality Assurance: Ensuring electrical steels meet specified resistivity, density, and stacking factor requirements for optimal magnetic performance and reliability.
- Material Characterization: Providing essential physical property data for engineers designing electrical machines, transformers, and other electromagnetic devices.
- Research and Development: Supporting experimental validation and improvement of magnetic materials through precise and repeatable physical measurements.
- Supply Chain Compliance: Enabling harmonized testing methods across international borders to facilitate material certification and compliance with industry regulations.
Adherence to IEC 60404-13 enhances consistency in magnetic material characterization, directly impacting efficiency and performance of electrical equipment utilizing these materials.
Related Standards
- IEC 60404 Series: Covers various aspects of magnetic materials including physical testing, magnetic property measurement, and magnetic material classifications.
- IEC 60068: Environmental testing for electrical and electronic products-complementary for evaluating material stability under operating conditions.
- ISO 9001: Quality management systems-supports integration of IEC 60404-13 testing procedures within broader quality assurance frameworks.
- ASTM Standards on Electrical Steel: Such as ASTM A677 and others provide complementary or alternative testing methods for electrical steel properties in certain regions or industries.
Implementing IEC 60404-13:2018 alongside these standards ensures comprehensive evaluation and management of magnetic steel materials for global industries focused on electrical and electronic technologies.
Keywords: IEC 60404-13, electrical steel, resistivity measurement, density measurement, stacking factor, magnetic materials testing, grain-oriented electrical steel, non-oriented electrical steel, van-der-Pauw method, gas pyknometer, electrical steel strip, electrical steel sheet, material characterization, magnetic material standards.
Open preview (PDF)Magnetic materials - Part 13: Methods of measurement of resistivity, density and stacking factor of electrical steel strip and sheet
