The present invention provides grain-oriented magnetic steel sheets that have a chromium-free insulating tension coating with excellent moisture absorption resistance and coating tension, and methods for producing such steel sheets.
A grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes a grain-oriented magnetic steel sheet and an insulating tension coating containing a phosphate salt and silica on a surface of the grain-oriented magnetic steel sheet, the coating further including a crystalline compound represented by the general formula (1) : M II 3 M III 4 (X v O 4 ) 6 ··· (1). In the formula (1), M II and M III are each independently one, or two or more selected from Sc, Ti, V, Mn, Fe, Co, Ni, Cu and Mg, and X V is one, or two or more selected from P, V and Mo. A method for producing a grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes applying an insulating tension coating liquid to a surface of a finish annealed grain-oriented magnetic steel sheet, the coating liquid including colloidal silica, a phosphate salt and a metal element M-containing compound in a specific ratio, and heat treating the steel sheet at least one time at a temperature of not less than 900°C in an atmosphere including a non-oxidizing gas and having a dew point of not more than 0°C.