| 摘要 |
PURPOSE:To form electrically insulating film having excellent punchability and after stress-relief annealing adhesion or electrical steel plate by the procedure in which a treating solution containing CrO3, various metal ions, boron acid, a resin emulsion etc. is coated on the surface of electrical steel plate, and then the steel plate is annealed in the air. CONSTITUTION:The 150pts.wt. of water is dissolved with 100pts.wt. of CrO3, 13-16pts.wt. (as Mg ion) of MgO, 1.5-4.5pts.wt. of at least one of Ca ion and Sr ion in the form of CaCl2 and Sr(NO3)2, 25-45pts.wt. of boric acid, and 5- 150pts.wt. (as solid) of an acrylic resin emulsion. Then, the solution thus obtained is coated on the surface of a steel plate and heated for baking in the air, and then the steel plate is subjected to a strain-relief annealing. Thus, electrically insulating film having excellent adhesion can be formed on steel plate after punching and annealing and excellent iron plate for the core of electric machine can be obtained. |
