ELECTROLYTIC ETCHING METHOD FOR GRAIN ORIENTED SILICON STEEL SHEET

PROBLEM TO BE SOLVED: To prevent the generation of arc spots in a grain oriented silicon steel strip, at the time of subjecting the steel strip to electrolytic etching, by specifying the surface roughness of a conductor roll to be brought into contact with the steel strip. SOLUTION: A grain oriented silicon steel contg. 2.0 to 4.0wt.% Si is subjected to hot rolling and cold rolling in succession to form into a grain oriented silicon steel strip having a final sheet thickness. On the surface of this steel strip, an etching mask is selectively formed, which is thereafter brought into contact with a conductor roll, furthermore, its direction is changed by a nonconductive deflector roll, it is immersed in an electrolytic bath of an electrolytic etching device and is subjected to electrolytic etching to form linear or dotted grooves on the surface of the steel strip. At this time, as the conductor roll, the one having >=0.1μm surface roughness Ra is used. In this way, the generation of arc spots on the surface of the grain oriented silicon steel strip is stably prevented to remarkably improve the quality of the steel strip.