KINETICS OF SECONDARY RECRYSTALLIZATION IN GRAIN-ORIENTED SILICON STEEL STUDIED BY HIGH-TEMPERATURE BACKGROUND

Abstract
Secondary recrystallization in grain-oriented silicon steel is studied by the high-temperature background damping. Abnormal grain growth involves an abrupt drop of the background. The temperatures of initiation and completion of the secondary recrystallization are, thus, determined for the same sample from the definite change in background with increasing temperature. The background measured on isothermal annealing yields a transposed sigmoidal curve consisting of three stages when plotted as a function of annealing time. Each stage except for the third is argued on the basis of the dislocation model of grain boundaries, involving Avrami's equation of the fraction recrystallized and following the theories of Johnson-Mehl and Avrami. Time law of growth is investigated. Activation energy is obtained for the second stage which is the principal stage of the secondary recrystallization in the steel.