Manufacturing methods and decarburization annealing furnace of oriented silicon steel sheet

摘要

PROBLEM TO BE SOLVED: To improve magnetic characteristics of a product by making the formation of an oxidized layer compatible with decarburization in the surface of a steel sheet in a decarburizing annealing stage for a grain oriented silicon steel sheet.;SOLUTION: In the method for producing the grain oriented silicon steel sheet where a silicon steel strip containing, by mass, 0.8 to 4.8% Si and 0.003 to 0.1% C is subjected to cold rolling and decarburizing annealing, is thereafter coated with a separation agent for annealing and is subjected to finish annealing, a part of a heating zone in the decarburizing annealing stage is annealed in an oxygen-containing atmosphere to form ferrous oxide on the surface of the steel sheet, and the steel sheet is further subjected to annealing where the atmospheric gas in a soaking zone is controlled to an oxidation degree (PH₂₀/PH₂) in which ferrous oxide is not formed.;COPYRIGHT: (C)2003,JPO