Armco Inc.

Francesco Gaudino

Jerry W Schoen

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.degree.-1125.degree. C. (1650.degree.-2050.degree. F.) for a time up to 10 minutes and slowly cooled to 480.degree.-650.degree. C. (900.degree.-1200.degree. F.) followed by rapid cooling to a temperature below 100.degree. C. (212.degree. F.). The annealed band must have a critical amount of austenite, .gamma..sub.1150.degree. 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.degree. 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.

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Butler, PA, United States of America

Francesco Gaudino