ONE-DIRECTIONAL SILICON STEEL PLATE EXCELLENT IN MAGNETIC CHARACTERISTICS AND PREPARATION THEREOF

摘要

PURPOSE:To obtain an unidirectional silicon steel plate excellent in close adhesivenes and further improved in magnetic characteristics, in an unidirectional silicon steel plate with a specific composition having a forsterite type insulating coating on the surface thereof, by containing a limited amount of iron in the aforementioned insulating coating. CONSTITUTION:A silicon steel plate containing, on the basis of a wt., 0.06% or less C, 2.0-4.0% Si, 0.003-0.05% Mo, 0.005-0.20% Sb and 0.10% or less S and/ or Se is hot rolled. After this steel plate is subjected to cold rolling including one time or more intermediate annealing to be finished into a predetermined plate thickness, decarburization annealing including recrystallization is subsequently applid to the finished steel plate and an annealing separation agent applied to the surface of the carburized steel plate to carry out final finish annealing. In this case, the separation agent is coated so as to contain 0.05- 5g/m2 product steel plate of an Fe component in a forsterite coating formed so as to contain MgO as a main component. After secondary recrystallizing annealing during the final finish annealing process is finished, the annealed steel plate is further heated in a H2 atmosphere to form a forsterite type insulating coating.