Effect of Ag Content on the Microstructure and Magnetic Properties of Grain-oriented Silicon Steels

The effect of Ag content in the range of 0-0.026 wt%, on the precipitates, microstructure, texture and magnetic properties of five grain-oriented electrical steels have been studied. A small quantity of Ag atoms with content less than 0.005 wt% only existed in the form of solid solution and promoted the nucleation rate of grain with {111} orientation on the grain boundary during decarburizing process. However, when Ag level rised to 0.012 wt%, some supersaturated Ag atoms precipitated from the matrix and in the form of single Ag-rich particles which inhibited the nucleation of the grains with (111) orientation and promoted the nucleation of grains with other orientation, such as Goss-orientation, during decarburizing process. The average grain size of decarburized bands decreased continuously as Ag content rised from 0 to 0.026 wt%. Compared to those final recrystallized bands with other Ag contents, the final recrystallized bands containing 0.012 wt% Ag obtained slightly larger average grain size. As Ag content rised from 0 to 0.026 wt%, magnetic flux density (B-8) firstly dramatically decreased and then abruptly increased, nevertheless, core loss (P-1.7/50) firstly slightly increased and then obviously decreased in final recrystallized bands. Final recrystallized bands with 0.026 wt% Ag obtained the best magnetic properties, whose core loss and magnetic flux density were 1.140 W/kg and 1.467 T, respectively.