Production method for grain oriented silicion steel sheet having excellent magnetic characteristics

Abstract

Method for producing a grain oriented silicon steel sheet comprises heating a silicon steel slab containing about: C : 0.01 to 0.10 wt %, Si: 2.5 to 4.5 wt %, Mn: 0.02 to 0.12 wt %, Al: 0.005 to 0.10 wt %, N : 0.004 to 0,015 wt %, to about 1280.degree. C. or higher and then subjecting it to hot rolling to prepare a hot-rolled steel sheet, subjecting the steel sheet to hot-rolled sheet annealing according to necessity, then subjecting it to one cold-rolling step or two or more cold-rolling steps with interposed intermediate annealing steps to prepare a cold-rolled steel sheet, and subjecting the cold-rolled steel sheet to decarburization annealing and finishing annealing, wherein the finishing rolling terminating temperature of the hot-rolling step is controlled to a range of about 900.degree. to 1100.degree. C., and the rolled sheet is processed so that the steel sheet temperature T(t) (.degree. C.) after time t falling in a range determined by an equation (1) which elapses from the termination of said hot finishing rolling approximately satisfies the equation (2): 2 seconds.ltoreq.t.ltoreq.6 seconds (1) T(t).ltoreq.FDT-(FDT-700)/6.times.t (2) wherein FDT represents the hot finishing termination temperature (.degree. C.).

Dependencies are inferred from the claim text.