Effect of Ultra-Fast Heating Before Decarburizing Annealing on Structural Transformations and Properties of Commercial Fe–3% Si Alloy

The effect of ultra-fast (induction) heating of a commercial Fe–3% Si alloy strip (grain oriented electrical steel) at a rate of ~100°С/s on the magnetic properties of finished product is studied in this work. This heating is accomplished after cold rolling followed by recrystallizing decarburizing annealing. It is shown that, in parallel with a reference sample, the ultra-fast heating leads (1) after recrystallizing decarburizing annealing to an increase in the average ferrite grain and, within the near-surface layer, to an increase in the edge component of the {110}〈001〉 texture and decrease in the fraction of {111}〈112〉 component; (2) after the second cold rolling at the final stages of annealing before secondary recrystallization, to an increase in the sharpness of the {110}〈001〉 component; and (3) in the finished product, to a decrease in the average macrograin size by 1.5 times (from ~9 to ~6 mm) and a decrease in the average angle of deviation of easy magnetization axes 〈001〉 from the rolling direction from ~7° to ~6°. The magnetic properties of the studied material exceed those of the comparison metal in all cases. The effect of ultra-fast heating on the texture transformations in the alloy and the formation of the final properties are explained by different nucleation places of grains of different orientations upon primary recrystallization.