Strip of a cobalt iron alloy, laminated core and method of producing a strip of a cobalt iron alloy

Abstract

A method of producing a strip from a CoFe alloy is provided. A slab consisting substantially 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 %, the remainder being Fe and up to 1 wt % of impurities, is hot rolled and then quenched from a temperature above 700° C. to less than 200° C. The hot rolled strip is cold rolled. The cold rolled strip is stationary annealed to produce an intermediate strip, and the intermediate strip is continuously annealed.

1 . A strip of a CoFe alloy, the strip comprising
 a composition consisting substantially 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 a remainder of Fe and up to 1 wt % of impurities, wherein the impurities may have one or more elements from the group consisting of O, N, S, P, Ce, Ti, Mg, Be, Cu, Mo and W,   a strip width of a maximum of 0.50 mm,   a permanent growth in length after magnetic annealing in the region of 700° C. up to the phase transition α→α+γ of a maximum of 0.08%,   an elongation to fracture A≥5% and a yield strength Rp0.2≤1000 MPa, and   a tensile strength Rm≥800 MPa.   
     
     
         2 . A strip according to  claim 1 , which furthermore has an inorganic coating. 
     
     
         3 . A strip according to  claim 2 , wherein the inorganic coating comprises MgO. 
     
     
         4 . A strip according to  claim 1 , wherein a difference between the permanent growth in the longitudinal direction and the permanent growth in the transverse direction of the strip is less than 0.08%. 
     
     
         5 . A laminated core, comprising a plurality of stacked sheets of a CoFe alloy, the alloy comprises
 a composition consisting substantially 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 %, the remainder being Fe as well as up to 1 wt % of impurities, wherein the impurities can have one or more from the group O, N, S, P, Ce, Ti, Mg, Be, Cu, Mo and W,   wherein the sheets have   a maximum thickness of 0.50 mm,   a permanent length growth, after annealing in the region of 700° C., up to the phase transition α→α+γ no more than 0.08%,   an elongation to fracture A 5%, a yield strength Rp0.2≤1000 MPa, and   a tensile strength Rm≥800 MPa.   
     
     
         6 . A laminated core according to  claim 5 , wherein the sheets have an inorganic coating. 
     
     
         7 . A laminated core according to  claim 6 , wherein the inorganic coating comprises MgO. 
     
     
         8 . A laminated core according to  claim 5 , wherein a difference between the permanent growth in the longitudinal direction and the permanent growth in the transverse direction of the strip is less than 0.08.