Method For Fabricating A Substantially Equiatomic Feco Alloy Cold Rolled Strip Or Sheet, Substantially Equiatomic Feco Alloy Cold Rolled Strip Or Sheet, And Magnetic Part Cut From Same

Abstract: The invention relates to a substantially equiatomic FeCo-alloy cold-rolled strip or sheet, and to a magnetic part cut from same, as well as to a method for fabricating a FeCo-alloy cold-rolled strip or sheet. A fully recrystallised hot-rolled sheet or strip is prepared, with a thickness of 1.5 - 2.5 mm and the following composition: 47.0% = Co = 51.0%; traces = V + W = 3.0%; traces = Ta + Zr = 0.5%; traces = Nb = 0.5%; traces = B = 0.05%; traces = Si = 3.0%; traces = Cr = 3.0%; traces = Ni = 5.0%; traces = Mn = 2.0%; traces = O = 0.03%; traces = N = 0.03%; traces = S= 0.005%; traces = P= 0.015; traces = Mo = 0.3%; traces = Cu = 0.5%; traces = Al = 0.01%; traces = Ti = 0.01%; traces = Ca + Mg = 0.05%; traces = rare earths = 500 ppm; the remainder being iron and impurities. A first cold-rolling step is carried out with a reduction rate of 70 to 90%, to bring the strip or sheet to a thickness = 1 mm. Intermediate annealing is carried out when running, leading to a partial recrystallisation of the strip or sheet, running at a speed (V), and where its temperature, in the useful zone of the furnace of useful length (Lu), is between Trc and 900°C, the strip or sheet remaining therein for 15 s to 5 min at a temperature (T) such that 26°C.min = (T - Trc).Lu/V = 160°C.min. The strip or sheet is cooled at least at 600°C/hour. A second step of cold-rolling the annealed strip or sheet is carried out, with a reduction rate of 60 to 80%, to bring the strip or sheet to a thickness of 0.05 to 0.25 mm. And final annealing (Rf) of the cold-rolled strip or sheet is carried out to achieve complete recrystallisation followed by cooling at 100 to 500°C/hour. Magnetic part, such as a magnetic core, obtained from a strip or sheet manufactured by this method.

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