Effect of solute carbon present during cold rolling and annealing on the texture and magnetic properties of non-oriented electrical steels

With the introduction of vacuum degassing in the production of non-oriented electrical steels, the carbon content is now often reduced in the molten steel stage, instead of during the final decarburising annealing treatment. This change of the process can be expected to influence the microstructure and texture development of these steels and so the final magnetic properties. The present paper deals with the effect of solute carbon - present during cold rolling and annealing - on the texture development and final properties of three electrical steels with various Si-contents. A lower excess amount of solute carbon results in a lower intensity of Goss grains and in a higher intensity of {111} grains, thus in a magnetically less favourable texture. This is because solute carbon hinders slip rotation and promotes shear band formation during rolling and retards high stored energy nucleation during recrystallisation. As a consequence, the magnetic polarisation of the final product - measured along the rolling direction - falls off with decreasing carbon content. Using the anisotropy energy as an evaluation criterion, a quantitative comparison between the magnetic polarisations and the measured textures is performed. Finally, the practical implications of the study are discussed.