ANNEALING SEPARATOR FOR GRAIN ORIENTED ELECTRICAL STEEL SHEET

摘要

Provided is an annealing separator for a grain oriented electrical steel sheet, which does not inhibit the flowability of an atmospheric gas during the transformation of a grain oriented electrical steel sheet into a coil-shaped product and the final annealing of the coil-shaped product and can prevent the occurrence of surface roughness. The annealing separator contains 0.01-0.05 mass% of Cl, 0.05-0.15 mass% of B, 0.1-2 mass% of CaO and 0.03-1.0 mass% of P2O3, and is mainly composed of magnesia having: a degree of activity of citric acid of 30-120 seconds as measured at 40% CAA; a specific surface area of 8-50 m2/g as measured by a BET method; an amount of hydration of 0.5-5.2 mass% as measured in terms of ignition loss; and a content of magnesia particles each having a particle diameter of 45 mum or more of 0.1 mass% or less, the annealing separator further containing a water-insoluble compound having a particle diameter of 45-150 mum inclusive in an amount of 0.05-20 mass% inclusive.