IEC 60404-8-5:2020

Overview

IEC 60404-8-5:2020 - Magnetic materials - Part 8-5: Specifications for individual materials - Electrical steel strip and sheet with specified mechanical properties and magnetic polarization - defines standardized grades and requirements for electrical steel strip and sheet used primarily in the poles and rims of rotating electrical machines. The standard sets out mechanical properties, magnetic polarization, geometrical characteristics, tolerances, technological characteristics and inspection procedures for both hot‑rolled and cold‑rolled grades (Class D21 of IEC 60404‑1).

Key technical updates in the 2020 edition:

• Inclusion of improved grades.
• Splitting of flatness into edge wave (wave factor) and residual curvature, aligning with IEC 60404‑9.
• Reduction of the test specimen length for geometrical determinations from 2 m to 1 m.

Key Topics and Requirements

• Classification and designation of hot‑rolled and cold‑rolled electrical steel strip and sheet.
• General requirements covering production process, form of supply, delivery condition and surface state.
• Mechanical properties: specified proof strength and tensile characteristics (as applicable to design and manufacturability).
• Magnetic polarization: defined magnetic performance parameters and test methods.
• Geometrical characteristics and tolerances: thickness, width, length, edge wave (wave factor), residual curvature, edge camber and related tolerance tables.
• Technological characteristics: e.g., density and suitability for cutting and welding.
• Inspection and testing: sampling, specimen preparation, test methods (references include Epstein frame methods in IEC 60404‑2 and d.c. measurements in IEC 60404‑4), retest rules and documentation.
• Marking, labelling, packaging and purchaser information requirements.

Applications and Who Uses This Standard

IEC 60404‑8‑5 is essential for:

• Steel manufacturers and mills producing electrical steel strip and sheet.
• Designers and manufacturers of rotating electrical machines (motors, generators) specifying pole and rim materials.
• Quality assurance and inspection teams ensuring conformity to magnetic and mechanical specifications.
• Procurement and technical purchasers who require clear material specifications and tolerances.
• Test laboratories using standardized methods (Epstein frame, d.c. tests) to verify magnetic polarization.

Practical benefits:

• Ensures consistent magnetic performance and mechanical strength for machine reliability.
• Reduces manufacturing issues by defining cut/weld suitability and flatness tolerances.
• Streamlines procurement with standardized grade designations and inspection procedures.

Related Standards

• IEC 60404‑1 (Classification)
• IEC 60404‑2 (Epstein frame measurement methods)
• IEC 60404‑4 (d.c. magnetic property measurement)
• IEC 60404‑9 (Geometrical characteristics methods)
• ISO 404, ISO 2566‑1, ISO 6892‑1 (related steel product and test method standards)

Keywords: IEC 60404-8-5, electrical steel strip and sheet, magnetic materials, magnetic polarization, mechanical properties, tolerances, rotating electrical machines, edge wave, residual curvature.