PRODUCTION OF UNIDIRECTIONALLY GRAIN ORIENTED ELECTRICAL STEEL SHEET BY USING RAPIDLY SOLIDIFIED THIN SLAB CAST IN SPECIFIC ATMOSPHERE

摘要

PURPOSE:To provide the process for production of the unidirectionally grain oriented electrical steel sheet which is a soft magnetic material to be used as the iron core material of electric equipment. CONSTITUTION:The atmosphere around a melt at the time of casting the slab and the atmosphere around the melt right after the solidification in the process for production of the unidirectionally grain oriented electrical steel sheet consisting in casting the slab consisting of, by weight, 0.025 to 0.1% C, 1.5 to 4.7% Si, 0.006 to 0.045% solAl, 0.0030 to 0.0130% N and consisting of the balance substantially iron at =1sec solidification rate at 8.5 deg.C and using this slab as a starting material and subjected to nitriding treatment in any stage from the slab casting to the start of the 2nd recrystalization are maintained at the atmosphere consisting of 1 to 100Torr N2 and the balance consisting of inert gases, such as He, Ne and Ar. Then, the components playing an important role in the development of secondary recrystals are controlled and the unidirectionally grain oriented electrical steel sheet having a high magnetic flux density is stably produce.