PRIMARY RECRYSTALLIZATION-ANNEALED SHEET FOR HIGH-MAGNETIC FLUX DENSITY UNIDIRECTIONAL ELECTRICAL STEEL SHEET

摘要

PURPOSE:To provide the annealed sheet by controlling the average crystal grain size and polar density of the {110} face for random bearings on the parallel surface of the plate surface at a 1/4 depth in a thickness direction and the dispersion of precipitates so as to satisfy specific equations. CONSTITUTION:The magnetic average crystal grain size D (mum) is determined by an image analysis method after primary recrystallization annealing. A sample is dissolved and filtered by a low potential electrolysis method and the residues are dissolved by a soln. mixture composed of HCl and HNO3 and filtered. On the other hand, the sample is dissolved by an iodine methanol soln. and filtered and the residues are dissolved by an NaOH soln and filtered. The contents of the Mn and Al in the respective filtrates are determined by an ICP method, by which the contents of MnS and AlN are determined as well. The volumetric fraction rho of the precipitates is determined from these contents. The base metal is electrolyzed by s SPEED method and the precipitates exposed on the electrolysis surface are stripped off by sticking an acetyl cellulose film thereto, by which a extraction replica is formed. The precipitation dispersion phase is then observed by transmission electron microscope, by which the particle size d (mum) thereof is determined and Z is calculated. Further, the X-ray extreme density N of the above-mentioned {110} face is measured and the equations I to V are satisfied.