| 摘要 |
PURPOSE:To form an insulating film with superior heat resistance by adding a specified amount of colloidal silica or colloidal alumina and boric acid to a composition consisting of phosphoric acid or one or more kinds of phosphates to prepare a treating fluid. CONSTITUTION:A steel sheet is cooled to <=300 deg.C after continuous annealing and coated with a treating fluid prepared by adding colloidal silica or colloidal alumina and boric acid to a composition consisting of phosphoric acid or one or more kinds of phosphates such as Al, Mg, Ca, Fe and Zn phosphates by 10-250pts. and 1- 150pts. to 10pts. P ion, respectively. The amount of the fluid coated is adjusted to about 0.05-1g/m<2> as solid. |
