Precipitation Behavior of AlN in High-Magnetic-Induction Grain-Oriented Silicon Steel Slab

The magnetic properties of high-magnetic-induction grain-oriented silicon steel are strongly related to the precipitation and dissolution of the AlN inhibitor. The three-dimensional morphology, size, quantity, and microstructure of AlN in oriented silicon steel slabs have been investigated by an electrolytic method, automated analysis technology for inclusions, and transmission electron microscopy. The AlN particles presented plate-like and rectangular blocks, precipitating more easily in the center of the slab. The morphology of AlN is determined by its hexagonal crystal system structure and growth rate in (210), (001), and (110) planes during solidification of the slab. Complete dissolution of AlN particles approaching 10 μm is difficult to achieve on thermal processing at 1423 K. Special attention should be paid to control of the precipitation size of AlN during solidification to improve the slab reheating process.