HIGHLY PRODUCTIVE FINISH ANNEALING HEATING METHOD OF GRAIN ORIENTED SILICON STEEL SHEET WITH LOW PRIMARY FILM DEFECT GENERATING AREA

摘要

PROBLEM TO BE SOLVED: To provide a method for heating a finish annealed coil for a grain oriented silicon steel sheet having a low primary film defect generating area and high productivity. SOLUTION: In a method for producing a grain oriented silicon steel sheet in which a silicon-contg. cold rolled steel sheet regulated to a final sheet thickness is subjected to decarburizing annealing serving both as decarburizing from the steel and primary recrystallization, is thereafter applied with a separation agent for annealing, is coiled into a coiled shape and is subjected to finish annealing, a method in which a part or the whole body of a heating method for a finish annealed coil is executed by a method for directly making the steel sheet itself hot is adopted, by which the whole body of the coil can uniformly be heated, and the oxidizing history of each part of the coil can be uniformized, so that film defects, particularly the film defects in the outer peripheral part of the coil can be suppressed.