Feco alloy, fesi alloy or fe sheet or strip and production method thereof, magnetic transformer core produced from said sheet or strip, and transformer comprising same

Abstract

Sheet or strip of cold-rolled and annealed ferrous alloy (1), characterized in that its composition is, in weight percentages: traces≤Co≤40%; if Co≥35%, traces≤Si≤1.0%; if traces≤Co<35%, traces≤Si≤3.5%; if traces≤Co<35%, Si+0.6% Al≤4.5−0.1% Co; traces≤Cr<10%; traces≤V+W+Mo+Ni≤4%; traces≤Mn≤4%; traces Al≤3%; traces≤S≤0.005%; traces≤P≤0.007%; traces≤Ni≤3%; traces≤Cu≤0.5%; traces≤Nb≤0.1%; traces≤Zr≤0.1%; traces≤Ti≤0.2%; traces≤N≤0.01%; traces≤Ca≤0.01%; traces≤Mg≤0.01%; traces≤Ta≤0.01%; traces≤B≤0.005%; traces≤O≤0.01%; the remainder being iron and impurities resulting from the preparation, in that, for an induction of 1.8 T, the maximum difference (Max Δλ) between the magnetostriction deformation amplitudes λ, measured parallel to the magnetic field (Ha) applied (λ/H) and perpendicular to the magnetic field (Ha) applied (λH) on three rectangular samples (2, 3, 4) of the said sheet or strip whose long sides are respectively parallel to the direction of rolling (DL) of the said sheet or strip, parallel to the transverse direction (DT) of the said sheet or strip, and parallel to the direction forming an angle of 45° with the said rolling direction (DL) and the said transverse direction (DT), being at most 25 ppm, and in that its recrystallization rate is 80 to 100%. Method of manufacturing such a sheet or strip, transformer magnetic core made from it and a transformer comprising it.