METHOD FOR PRODUCING DIRECTIONAL ELECTROMAGNETIC STEEL SHEET

摘要

According to the present invention, a grain oriented electrical steel sheet in which iron loss has been further reduced can be obtained by carrying out decarburization annealing as continuous annealing including: (1) heating the steel sheet to a temperature in the range of 700°C to 750°C at heating rate of 50°C/second or higher at least in a temperature range of 500°C to 700°C in an atmosphere having oxidation potential P(H 2 O)/P(H 2 ) equal to or lower than 0.05; (2) then cooling the steel sheet to a temperature range below 700°C in an atmosphere having oxidation potential P(H 2 O)/P(H 2 ) equal to or lower than 0.05; and (3) reheating the steel sheet to a temperature in the range of 800°C to 900°C and retaining the steel sheet at the temperature for soaking in an atmosphere having oxidation potential P(H 2 O)/P(H 2 ) equal to or higher than 0.3.