INFLUENCE OF HEAT-TREATMENT BEFORE SECONDARY RECRYSTALLIZATION ON MAGNETIC-PROPERTIES OF 3-PERCENT SI GRAIN-ORIENTED STEEL CONTAINING SB

The secondary recrystallization of 3% Si grain-oriented steel containi ng Sb has been investigated. The mechanism of the improvement of the m agnetic properties under the conditions of Sb addition and a constant temperature treatment during secondary recrystallization has been clar ified by three experiments. It has been found that (1) Sb segregation in grain boundaries during decarburization annealing retards decarburi zation and grain growth, so that the {110} intensity increases acid th e grain size decreases with increasing Sb; (2) the constant temperatur e treatment for final annealing enhances the Sb segregation in grain b oundaries, and therefore maintains the {110} intensity in the specimen with the addition of Sb; and (3) the addition of Sb increases the inh ibiting force. These three effects enable secondary recrystallization such that many (110)[001] nuclei grow rapidly, surrounded by small pri mary grains, leading to high B-s values.