| 摘要 |
PURPOSE:To improve the adhesiveness and durability of a tensile coating layer on a specular surface and to obtain the titled steel sheet in a method for improving the iron loss of a grain oriented silicon steel sheet by finishing the sheet to the specular surface by specifying a separating agent for annealing to be used in the stage of finish annealing. CONSTITUTION:A hot rolled sheet of a silicon steel slab is subjected to one or two passes of cold rolling including intermediate annealing to a final sheet thickness and is then subjected to decarburization and primary recrystallization annealing. The separating agent for annealing (for example, MgO contg. >=50%>=1 kinds among Al2O3, ZrO2 and TiO2) consisting of the component compsn. to suppress the reaction for forming forsterite with the surface layer of the steel sheet essentially consisting of Si and Fe oxide is thereafter coated on the surface of the steel sheet. Such steel sheet is subjected to the final finish annealing including secondary recrystallization and purification annealing and after the non-metallic layer on the surface is removed, the surface is polished to the specular surface having <=0.4mu center line average height. The tensile film consisting of >=1 kinds among the nitrides and/or carbides of Ti, Nb, Si, V, etc., and the oxides of Al, Si, Zn, etc., is deposited by a CVD or PVD method to 0.005-5mu thickness on such surface. |
