| 摘要 |
PROBLEM TO BE SOLVED: To surely raise the temp. without overshooting or insufficient heating at the time of heating in a decarburize-annealing process by controlling temp. deviation from the targeted heating transition to a value within a specific range while the heating temp. of a strip for grain oriented electrical steel sheet containing a specific ratio or lower of Si is in a specific range and decarburizing. SOLUTION: The strip for grain oriented electrical steel sheet cold-rolled to a finish strip thickness and containing <=4.5% Si, is decarburized. At this time, while the steel strip at the heating step of the strip is at 600-800 deg.C, the temp. deviation from the targeted heating transition is controlled to within±15 deg.C, the decarburize-annealing is executed. Desirably, the strip is heated by a gas heating system with a radiant tube until the steel strip temp. at the heating step of the strip is 550-650 deg.C, and successively, the strip is heated by an electric heating system with a tubular heater till reaching a soaking temp. higher than the above temp. and at the soaking step, the soaking is executed by an element heater system.
|
