PRODUCTION OF GRAIN ORIENTED SILICON STEEL SHEET EXCELLENT IN CORE LOSS CHARACTERISTIC

摘要

PROBLEM TO BE SOLVED: To obtain a steel sheet excellent in core loss characteristics by forming a tensile insulating film on the surface of a finish-annealed steel sheet subjected to etching treatment with an SiCl4 soln. or a pickling soln. contg. SiCl4 and reduced by a specified weight. ;SOLUTION: A silicon steel continuously cast slab contg., by weight, 0.075% C, 3.32% Si, 0.075% Mn, 0.020% Se, and Sb, Al, N and Mo, and the balance Fe is heated at ≥1300°C and is thereafter subjected to hot rolling, annealing and cold rolling to form into a cold rolled sheet of 0.1 to 0.5 mm. By electrolytic etching, linear grooves are formed on the surface. The loss in weight of the steel sheet after etching treatment is preferably controlled to 1.0 to 20.0g/m2. After decarburizing annealing and final annealing, it is dipped into an aq. soln. of 1 to 20% SiCl4 heated at 50 to 100°C for 1 to 100 sec and is water-washed and dried. A tensile insulating film of 0.5 to 5 μm thickness essentially consisting of magnesium phosphate and colloidal silica is formed on the surface, which is baked at 500 to 1000°C to obtain a grain oriented silicon steel sheet excellent in core loss characteristics and magnetostriction characteristics.;COPYRIGHT: (C)2000,JPO