| 摘要 |
PURPOSE: To effectively prevent the occurrence of steel strip fracture originated from linear grooves at the adge by controlling the amount of etching in the width direction of a steel strip, at the time of forming, by etching, grooves of linear or a dotted-line shape on the surface of a cold rolled strip of grain- oriented silicon steel. CONSTITUTION: A grain-oriented silicon steel stock containing 2.0-4.0wt.% Si is cold-rolled and finished to 0.15-0.35mm final sheet thickness. Subsequently, an etching mask is provided to this steel strip and electrolytic etching is performed fo form grooves of linear or dotted-line shape having 5-35μm depth and 2-10mm pitch on the surface. Then, final finish annealing is applied to this steel strip to fractionize a magnetic domain to obtain the grain oriented silicon steel sheet improved in magnetic properties. At the time of the electrolytic etching, etching at the edge in the width direction of the steel strip is controlled to regulate the groove depth at the width-direction edge to <=70% of the groove depth in the central part. This control of the amount of electrolytic etching can be executed, e.g. by providing a shielding means between the silicon steel strip and an electrode. |
