Non-oriented electrical steel and method for manufacturing the non-oriented electrical steel.

A non-oriented electrical steel sheet with optimized elemental composition and microstructure addresses the challenge of high eddy current loss by achieving low eddy current loss, high mechanical strength, and magnetic performance, suitable for high-speed motors.

JP2026520248APending Publication Date: 2026-06-23ARCELORMITTAL SA
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Patent Information

Authority / Receiving Office
JP · JP
Patent Type
Applications
Current Assignee / Owner
ARCELORMITTAL SA
Filing Date
2024-11-14
Publication Date
2026-06-23

AI Technical Summary

Technical Problem

Existing non-oriented electrical steel sheets face challenges in achieving low eddy current loss while maintaining mechanical properties and magnetic performance, particularly in high-speed motors, with previous methods either reducing thickness or adding alloying elements leading to limitations in torque, rigidity, and magnetic properties.

Method used

A non-oriented electrical steel sheet with specific elemental composition (C: 0.0001% to 0.007%, Si: 2.9% to 3.4%, Mn: 0.15% to 0.25%, Al: 0.7% to 1.3%, Ni: 0.05% to 1%, P: 0% to 0.15%, N: 0.09% or less, Ti: 0% to 0.1%, Nb: 0% to 0.1%, V: 0% to 0.1%, Cr: 0% to 1%, Mo: 0% to 0.5%, W: 0% to 0.1%, Co: 0% to 1%, As: 0% to 0.05%, Cu: 0% to 1%, B: 0% to 0.05%, Ca: 0.001% to 0.01%, Sn: 0% to 0.2%, Pb: 0% to 0.2%, Sb: 0% to 0.2%, with a total Si, Mn, Al content of 3.85% to 5.5%) and a microstructure of 80% to 100% recrystallized ferrite grains, produced through controlled hot rolling, annealing, and cold rolling processes.

Benefits of technology

The steel achieves eddy current loss of less than 35%, ultimate tensile strength of 530 MPa, yield strength of 400 MPa, total elongation of 13%, magnetic polarization of 5000 A/m, and total losses of 11-14 W/kg, with excellent punchability and coating properties, suitable for conventional industrial applications.

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Abstract

The present invention relates to a non-oriented electrical steel sheet having a composition expressed in weight percent containing the following elements: 0.0001% ≤ carbon ≤ 0.007%, 0.15% ≤ manganese ≤ 0.25%, 2.9% ≤ silicon ≤ 3.4%, 0.7% ≤ aluminum ≤ 1.3%, 0.05% ≤ nickel ≤ 1%, phosphorus ≤ 0.15%, sulfur ≤ 0.006%, nitrogen ≤ 0.09%, provided that 3.85% ≤ Si + Al + Mn ≤ 5.5%, and may contain one or more of the following optional elements: 0% ≤ niobium ≤ 0.1%, 0% ≤ titanium ≤ 0.1%, 0% ≤ vanadium ≤ 0.1%, 0% ≤ chromium ≤ 1%, 0% ≤ molybdenum ≤ 0.5%, 0% ≤ tungsten ≤ 0.1%, 0% ≤ cobalt ≤ 1%, 0% ≤ arsenic ≤ 0.05%. We handle non-oriented electrical steel sheets having a percentage of eddy current loss in total iron loss measured at 1T and 400Hz according to IEC 60404-2 standard, which is less than 35% when calculated according to the Bertotti method. The remaining composition consists of iron and unavoidable impurities caused by processing, and the microstructure of the steel sheet is made from ferrite and includes, in area fraction, 80% to 100% recrystallized microstructure and 0% to 20% non-recrystallized microstructure, with an average grain size of 20 microns to 110 microns for the recrystallized microstructure, and a percentage of eddy current loss in total iron loss measured at 1T and 400Hz according to IEC 60404-2 standard, which is less than 35% when calculated according to the Bertotti method.
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