Process to produce regular oriented granulation electric steel with a measured permeability at 796 A / m from 1780 to 1880 and process to produce regular oriented granulated electric steel with a measured permeability at least 7980 A / m from 1780

摘要

The present invention produces a regular grain oriented electrical steel using a single cold reduction step having excellent and highly uniform magnetic quality. The method includes the steps of providing an electrical steel band having Mn of 0.024% or less in excess of that needed to combine with S and/or Se. The band is provided with an anneal at a temperature of from 900-1125 DEG C (1650-2050 DEG F) for a time up to 10 minutes and slowly cooled to 480-650 DEG C (900-1200 DEG F) followed by rapid cooling to a temperature below 100 DEG C (212 DEG F). The annealed band must have a critical amount of austenite, gamma 1150 DEG C, of 7% or more. The annealed band is cold reduced in a single stage to the desired final thickness. The strip is decarburized and provided with an annealing separator coating on one or more surfaces of the strip. Before or during the final high temperature anneal, a total S level at least 15 mg per square meter is provided. The strip is final annealed at a temperature of 1100 DEG C or higher to effect secondary grain growth. The finished regular grain oriented electrical steel has far superior and more uniform magnetic quality than available from previous single stage processes, and which magnetic quality is comparable to regular grain oriented electrical steels made using processes requiring two stages of cold reduction separated by an annealing step.