INFLUENCE OF HEATING RATE ON THE DECARBURIZED ANNEALING MICROSTRUCTURE AND TEXTURE IN LOW-CARBON NON-ORIENTED ELECTRICAL STEEL

The present work investigates the effect of heating rate on the evolution of decarburized microstructures and textures in low-carbon electrical steels within the inter-critical temperature region. The results show that heating rate has a significant effect on both the final microstructures and textures during the process of decarburization annealing. The "nucleation" sites of columnar grains are determined by the heating rate. Slow heating rate would have the "nuclei" formed within a certain range of the surface layer, and finally leading to a fine-grained layer near the sample surface. By comparison, a complete columnar microstructure is acquired under the rapid heating condition. Strong gamma-fiber and relatively weak alpha-fiber components were obtained at the slow heating rate. In contrast, y-fiber texture is greatly weakened and a-fiber component slightly strengthened under the rapid heating condition, and a relatively strong {001}<120> texture is formed at the same time. The experimental results prove that the final decarburized textures are mainly dependent upon the texture component of recrystallized grains in the "nucleation" sites.