On the Influence of Order on the Soft Magnetic Properties of Fe‐Si Alloys

Five high‐Si steels (1.9, 3.3, 4.2, 5 and 5.6 wt.% Si) were processed by conventional hot and cold rolling. Using a proper thermomechanical schedule, it was possible to produce final sheets with a thickness of 0.5‐0.7 mm. For two of the steels with 4.2 and 5.6 wt. % Si different cooling rates after hot rolling were applied in order to study the influence of ordering phenomena on the workability of the material. Mössbauer spectroscopy was used to characterize the degree of order of the steels along their thermomechanical processing. Long‐range order parameters were directly obtained from the Mössbauer spectra analysis. Results show that D0₃ order enhancement causes deterioration of the ductility above 3.5 wt.%Si. In addition, the limitation of order enhancement during cooling seems to be the reason for the improved workability in the fast cooled samples: the slower the cooling, the higher the degree of order, with a consequent decrease in ductility. Power losses and magnetic polarization were measured after cold rolling and annealing. An influence of order on the magnetic properties is discussed: order enhancement seems to cause a detriment to the power losses.