Efeito do perfil térmico de recozimento das bobinas laminadas a quente nas propriedades do aço elétrico de grão orientado

Abstract

This paper studied the effect of hot band normalizing on the magnetic properties of the grain-oriented electrical steel processed with two-stage cold rolling. Samples with 2.45 mm thickness were normalized at 600°C, 800°C, 950°C and 1050°C for periods of 35s, 50s and 90s and the results were compared with a sample not annealed. The temperatures and times were determined as to be applicable in the industrial process with the current equipment. After normalizing, all samples were subjected to the following steps: cold rolling to 0.73 mm, intermediate annealing, cold rolling to 0.27 mm, primary recrystallization, secondary recrystallization and coating application. The results of magnetic loss were evaluated and sought to explain the phenomena by metallographic analysis and characterization of the texture along each step of the process. There were no significant changes in the microstructure of the material normalized for the material not normalized. With respect to magnetic loss, increased soaking time has proved beneficial for temperatures above 800°C and detrimental to 600°C. The evolution of texture in the process steps was not enough to explain the influence of annealing on the initial results of magnetic loss. It has been shown that it is possible to eliminate the normalizing process and obtain satisfactory magnetic loss.