Research progress in normalizing of grain-oriented silicon steel and effect on secondary recrystallization

The grain-oriented silicon steel is an important iron core material, and normalization is an indispensable industrial production process for the production of high magnetic induction grain-oriented silicon steel at present. It can adjust the structure, texture and inhibitor precipitation of hot-rolled band to improve the magnetic properties of silicon steel. The inheritance from hot rolled microstructures to normalized ones of grain-oriented silicon steel and the evolution law of inhibitor during the process of normalizing were summarized, and the influence of normalizing on the microstructure and texture of primary recrystallization and secondary recrystallization was mainly discussed. It is pointed out that the fine gamma-oriented grain colonies formed during normalizing favour the final secondary recrystallization whilst the coarse and deformed alpha-/lambda-oriented grains disfavour it. Finally, a three-stage normalization process and its parameters for optimizing magnetic properties of low-temperature heating nitriding type high magnetic induction grain-oriented silicon steel were recommended. The key research direction of normalizing in the future is to further simplify process on the basis of ensuring the same texture and inhibitor content, and rational application of normalizing process in the grain-oriented silicon steel produced by thin slab casting and rolling and strip casting.