US 12,110,579 B2
Method of producing a CoFe alloy strip
Niklas Volbers, Bruchkobel (DE); Manuel Demper, Dautphetal (DE); and Joachim Gerster, Alzenau (DE)
Assigned to VACUUMSCHMELZE GMBH & CO. KG, Hanau (DE)
Filed by VACUUMSCHMELZE GMBH & CO KG, Hanau (DE)
Filed on Aug. 9, 2021, as Appl. No. 17/397,295.
Claims priority of application No. 20191604 (EP), filed on Aug. 18, 2020.
Prior Publication US 2022/0056568 A1, Feb. 24, 2022
Int. Cl. C22F 1/16 (2006.01); C21D 1/04 (2006.01); C21D 6/00 (2006.01); C21D 8/12 (2006.01); C22C 30/00 (2006.01); H01F 1/147 (2006.01); H02K 15/02 (2006.01)
CPC C22F 1/16 (2013.01) [C21D 1/04 (2013.01); C21D 8/1244 (2013.01); C22C 30/00 (2013.01); H01F 1/147 (2013.01); H02K 15/02 (2013.01); C21D 6/007 (2013.01); C21D 8/1222 (2013.01); C21D 8/1233 (2013.01); C21D 8/1261 (2013.01); C21D 8/1272 (2013.01); C21D 8/1283 (2013.01); C22C 2202/02 (2013.01)] 26 Claims
OG exemplary drawing
 
1. A method of producing a CoFe alloy strip, comprising:
hot rolling a CoFe alloy to form a hot rolled strip, followed by quenching the strip from a temperature above 700° C. to a temperature of 200° C., wherein the CoFe alloy consists essentially of 35 wt %≤Co≤55 wt %, 0 wt %≤V≤3 wt %, 0 wt %≤Ni≤2 wt %, 0 wt %≤Nb≤0.50 wt %, 0 wt %≤Zr+Ta≤1.5 wt %, 0 wt %≤Cr≤3 wt %, 0 wt %≤Si≤3 wt %, 0 wt %≤Al≤1 wt %, 0 wt %≤Mn≤1 wt %, 0 wt %≤B≤0.25 wt %, 0 wt %≤C≤0.1 wt %, with the remainder being Fe as well as up to 1 wt % of impurities, wherein the impurities may comprise one or more elements from the group consisting of O, N, S, P, Ce, Ti, Mg, Be, Cu, Mo, W and up to 0.2 wt % of other impurities, and the CoFe alloy comprises an order/disorder temperature To/d and a ferritic/austenitic transformation temperature Tα/γ, wherein Tα/γ>To/d, cold rolling the quenched hot rolled strip, and the cold rolled strip has a thickness which is less than 0.50 mm after the cold rolling step,
after cold rolling, continuous annealing the strip at a maximum temperature T1, wherein T1 is less than the order/disorder temperature To/d and 660° C.<T1<700° C., followed by cooling at a cooling rate R1 of at least 1 K/s in the temperature range of T1 to 500° C.,
forming a plurality of laminations from the strip, and
annealing the laminations at a temperature between 730° C. and Tα/γ and stacking the annealed laminations to form a laminated core.