Secondary recrystallization in grain-oriented silicon steel

Abstract

Grain-oriented silicon steel is a soft magnetic material widely used for transformer cores. Magnetic properties are closely related to the sharpness of Goss texture, which is evolved by secondary recrystallization. An overview of our results will be presented; secondary recrystallization behaviour has been investigated by in situ observation utilizing synchrotron x-ray topography. The results support the selective growth mechanism. Migration of Goss grains is controlled by inhibitor and sharper Goss grains, which have higher frequency of CSL-boundaries to the matrix, start to grow preferentially while the other grains are stagnated by inhibitor. Secondary recrystallization behaviour can be explained based on this CSL-model. At the initial stage, inhibitor gradient through the thickness promotes Goss selective growth from the subsurface layer and at the later stage, inhibitor drop rate dominates the Goss selective growth. Inhibitor and CSL-boundaries synergistically affect Goss selective growth and Goss grain evolves to a coarse grain.