Effect of silicon on the loss separation and permeability of laminated steels

Abstract

The effect of silicon content in the range from 0.21 to 2.0 wt% on the ac and dc magnetic properties of laminated steels after box annealing at 800°C for 5 h measured at 1.0 and 1.5 T induction has been investigated. Because of the combined effect of the hot-rolled plate grain size and the slowing down of grain boundary movement by silicon, steel containing 1.26 wt% silicon content had a maximum grain diameter after box annealing. Besides steel containing 1.26 wt% silicon, the texture of laminated steels was improved with increasing silicon content. The electrical resistivity of laminated steels increased linearly with increasing silicon content. The ac core loss, apparent eddy current loss, and classical eddy current loss of laminated steels decreased with increasing silicon content at both inductions. Silicon improved the ac core loss, hysteresis loss, classical eddy current loss and apparent eddy current loss through the combined effects of grain coarsening, texture improvement and increasing electrical resistivity. At 1.0 T induction, the variation of the ac and dc permeability with respect to silicon content was similar to that of grain size. It is suggested that the effect of grain size on permeability is more pronounced than that of texture at low induction. On the other hand, at 1.5 T induction, the variation of the ac and dc permeability and magnetic flux density with respect to silicon content were similar to that of the texture component ( I/ I R) 200. It is suggested that the effect of texture on permeability and magnetic flux density is more significant than that of grain size at high induction.