| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a silicon steel sheet in which an insulating coating film capable of imparting strong tension can be formed even on the surface of the silicon steel sheet whose surface has been made smooth and in which further reduction of core loss is made possible. SOLUTION: A soln. contg. colloidal silica, boric acid and either or both of zinc oxide and lead oxide is prepd. in such a manner that the atomic ratio (a):(b):(c) of Si contained in colloidal silica, B contained in boric acid and Zn or Pb or the total of Zn+Pb contained in zinc oxide and/or lead oxide is in the ranges of a=0 to 6, b=2 to 16 and, a+b/2+c=10. The solution is then applied on a steel sheet after final finish annealing, and then heating is executed at 600 to 1100 deg.C for 10 to 300 sec to form an insulating coating film. |
