Development of rapidly solidified 6.5 wt% silicon steel for magnetic applications

Abstract

The 6.5wt% Silicon steel has always a technological importance owing to its soft magnetic properties and low core losses. In this research, this steel is prepared in the form of continuous ribbons of 25 mm width and 35 mm thickness by rapid solidification technique using melt spinner. The as-cast ribbons show single phase of α-FeSi as observed from x-ray diffraction. By transmission electron microscopy (TEM), the alloy shows disordered A2 structure in as-cast ribbon while B2 ordered phase forms from the A2 matrix at annealed condition. Two magnetization temperatures are observed at 670 and 760°C due to the phase transformation of B2 and A2 structures, respectively. The alloy showed enhancement in the soft magnetic properties with reduction in coercivity from 1.90Oe in the as-cast state to 0.58Oe when annealed at 850°C. The lowering of coercivity is due to the formation of ordered B2 phase during annealing.