The Mechanism of Heating Rate on the Secondary Recrystallization Evolution in Grain Oriented Silicon Steel

Grain-oriented silicon steels were prepared at different heating rates during high temperature annealing, in which the evolution of magnetic properties, grain orientations and precipitates were studied. To illustrate the Zener factor, the diameter and number density of precipitates of interrupted testing samples were statistically calculated. The effect of precipitate ripening on the Goss texture and magnetic property was investigated. Data indicated that the trend of Zener factor was similar under different heating rates, first increasing and then decreasing, and that the precipitate maturing was greatly inhibited as the heating rate increased. Secondary recrystallization was developed at the temperature of 1 010. when a heating rate of 5 degrees C/h was used, resulting in Goss, Brass and {110} <227> oriented grains growing abnormally and a magnetic induction intensity of 1.90T. Furthermore, increasing the heating rate to 20 degrees/h would inhibit the development of undesirable oriented grains and obtain a sharp Goss texture. However, when the heating rate was extremely fast, such as 40 degrees C/h, poor secondary recrystallization was developed with many island grains, corresponding to a decrease in magnetic induction intensity to 1.87 T. At a suitable heating rate of 20 degrees C/h, the sharpest Goss texture and the highest magnetic induction of 1.94 T with an onset secondary recrystallization temperature of 1 020 degrees C were found among the experimental variables in this study. The heating rate affected the initial temperature of secondary recrystallization by controlling the maturation of precipitates, leading to the deviation and dispersion of Goss texture, thereby reducing the magnetic properties.