| 摘要 |
PURPOSE:To manufacture a thick electrical plate for D.C. magnetization having high magnetic flux density in a low magnetic field and reduced in differences in magnetic flux properties in a plate-thickness direction by limiting the components of a steel stock and carrying out crystal grain regulation simultaneously with dehydrogenation heat treatment after rolling. CONSTITUTION:A slab or cast slab having a composition consisting of, by weight, <=0.01% C, 0.1-1.0% Si, <=0.20% Mn, <=0.015% P, <=0.010% S, <=0.05% Cr, <=0.05% Mo, <=0.01% Cu, <=0.005% Al, <=0.004% N, <=0.005% O, <=0.0002% H, and the balance essentially iron is heated to 1150-1300 deg.C and subjected to rolling in which single or more rolling passes of >=0.7 reduction ratio A represented by an equation are applied under the condition of >=900 deg.C finishing temp. Subsequently, the thick plate of >=50mm thick is subjected to dehydrogenation heat treatment at 600-750 deg.C and, if necessary, to annealing at 750-950 deg.C or to normalizing at 910-1000 deg.C, and the thick plate of 20-<50mm thick is subjected to annealing at 750-950 deg.C or to normalizing at 910-1000 deg.C. By this method, the thick electrical plate of >=20mm plate thickness having magnetic properties of >=0.8T magnetic flux density in a magnetic field of 80A/m can be obtained. |
