| US 7,501,028 B2 | ||
| Non-grain oriented magnetic steel strip or magnetic steel sheet and method for its production | ||
| Brigitte Hammer, Voerde (Germany); Karl Ernst Friedrich, Moers (Germany); Olaf Fischer, Bochum (Germany); Jürgen Schneider, Bochum (Germany); and Carl-Dieter Wuppermann, Krefeld (Germany) | ||
| Assigned to ThyssenKrupp Stahl AG, Duisburg (Germany) | ||
| Appl. No. 10/514,983 PCT Filed May 15, 2003, PCT No. PCT/EP03/05114 § 371(c)(1), (2), (4) Date Jul. 01, 2005, PCT Pub. No. WO03/097884, PCT Pub. Date Nov. 27, 2003. |
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| Claims priority of application No. 102 21 793 (DE), filed on May 15, 2002. | ||
| Prior Publication US 2005/0247373 A1, Nov. 10, 2005 | ||
| Int. Cl. H01F 1/147 (2006.01) | ||
| U.S. Cl. 148—111 [148/306] | 15 Claims |
| 1. Method for producing a non-grain oriented magnetic steel strip or non-grain oriented magnetic steel sheet, comprising the
following steps:
casting a steel which, in addition to iron, contains unavoidable impurities (in weight %) C: <0.005%, Mn: ≤1.0%, P: <0.8%,
Al: <1% and Si providing that 1.4%<% Si+2% Al<2.5% (where % Si=Si content and % Al=Al content) to form a fabricated material,
processing the fabricated material to form a hot strip in a hot rolling process at hot rolling temperatures which, starting
from ≤1,300° C., are adjusted in such a way that with substantially complete exclusion of a purely austenitic structure (γ
phase) a first temperature range is passed through in which a processed steel has an austenite/ferrite dual phase multi-structure
(α, γ multi-phases),
so the magnetic steel strip or magnetic steel sheet, after a surface treatment including etching, cold rolling and annealing
of the hot strip obtained after the hot rolling process, has a magnetic polarisation J2500≧1.74 T, measured in a 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 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,
wherein a span, AT, of a second temperature range within which the processed steel has the purely austenitic structure (γ phase) is less than
50° C., and
wherein temperature during the hot rolling process is controlled while avoiding the span, AT, of the second temperature range.
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