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 o 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 o C. The lowering of coercivity is due to the formation of ordered B2 phase during annealing.

Importance of Surface Roughness on the Magnetic Properties of Additively Manufactured FeSi Thin Walls

“…It is possible to normalise this data in such a way as the sample is a single phase material and therefore the saturation magnetisation depends only on the volume of material. Heat treatment may cause the introduction of B2 and D03 phases as the samples were furnace cooled, however should not impact on the saturation of the material [32]. To ensure this is correct, several samples were tested before and after heat treatment, and were found to have the same M sat during VSM measures.…”

The influence of silicon content on physical properties of non-oriented silicon steel

“…However, due to the increase in the number of antiphase domain boundaries with an increase in disordering, Ruiz et al [44] discovered that this lead to the pinning of domain walls and increase the hysteresis losses of the electrical steel. Therefore if magnetic hysteresis is the main concern for losses, ordered phases may be necessary [54].…”

Characterization of ordering in Fe-6.5%Si alloy using X-ray, TEM, and magnetic TGA methods

“…To prepare ductile thin sheet of Fe-6.5%Si for soft magnetic applications, the ordered phases have to be suppressed. The reported thermomechanical processing [8,9], rapid solidification/melt spinning [10][11][12][13][14][15][16][17][18], and deposition/diffusion annealing [19][20][21] were found successful in the lab scale only because the formation of ordered phases were carefully controlled. The amount of ordered phases or ordering degree is therefore vital for the success of Fe-6.5%Si production, and should be a parameter closely monitored.…”