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 PO 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 m/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 µm or more of 0.1 mass% or less the annealing separator further containing a water insoluble compound having a particle diameter of 45 150 µm inclusive in an amount of 0.05 20 mass% inclusive.