Non-grain oriented magnetic steel strip or magnetic steel sheet and method for its production

US7501028B2 · kind B2 · utility

Assignee

• THYSSEN KRUPP STAHL AG · DE

Inventors

• Brigitte Hammer · Voerde, DE
• Karl Ernst Friedrich · Moers, DE
• Olaf Fischer · Bochum, DE
• Jürgen Schneider · Kirchzarten, DE
• Carl-Dieter Wuppermann · Krefeld, DE

Key dates

• Filing date: May 15, 2003
• Grant date: Mar 10, 2009
• Expiry date: Jun 22, 2024

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D8/0273
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The invention relates to non-grain oriented magnetic steel sheets which can be produced as final annealed and as a non-final annealed types in such a way that they have improved magnetic polarisation and reduced magnetic reversal losses compared with the previously achieved values. This is achieved in that a suitably composed steel, during its cooling starting from a maximum initial temperature of 1,300° C., passes through a temperature range with substantially complete exclusion of a purely austenitic structure (γ phase), in which range it comprises an austenite/ferrite dual phase multi-structure (α, γ multi-phases), so the magnetic steel sheet, after hot rolling, etching, cold rolling and annealing of the hot strip obtained after hot rolling, has a magnetic polarisation J2500≧1.74 T, measured in the longitudinal direction of the strip or sheet and at a magnetic field strength of 2,500 A/m and a value P1.5(50) of the magnetic losses of <4.5 W/kg, measured in the longitudinal direction of the strip at J=1.5 T and a frequency f=50 Hz.