Sn Segregation and Its Influence on Electrical Steel Texture Development.

During the recrystallization microalloyed Sn in non-oriented electrical steel segregates to the surface and on grain boundary and affects the texture development. In spite of the fact that the grain boundary segregation is much smaller compared to surface segregation, both have an influence on recrystallization and on texture development in electrical steel. Auger electron spectroscopy (AES) was used to measure the grain boundary and surface segregation of Sn in non-oriented electrical steels alloyed with different Sn weight contents (0.025, 0.05 and 0.1 %). The grain boundary segregation of the specimens, which were previously aged at 530ºC for various times and were fractured under UHV conditions, was measured. The surface segregation temperature dependence and its kinetics were followed in polycrystalline specimens in the temperature range from 400 to 900ºC on the grains of known crystallographic orientations: (100), (111) and (110). The textures were measured by X-ray texture goniometer and the results were presented as orientation distribution functions (ODF). By controlled surface and grain boundary segregation it is possible to achieve the selective grain growth which improves the electrical properties of non-oriented electrical steel. The best results were obtained by alloying it with 0.05 wt% Sn.