Effect of normalizing cooling process on microstructure and precipitates in low-temperature silicon steel
(1. College of Metallurgy and Energy, Hebei United University, Tangshan 063009, China;
2. School of Metallurgical and Ecological Engineering,
University of Science and Technology Beijing, Beijing 100083, China)
2. School of Metallurgical and Ecological Engineering,
University of Science and Technology Beijing, Beijing 100083, China)
Abstract: Microstructure, precipitate and magnetic characteristic of final products with different normalizing cooling processes for Fe-3.2%Si low-temperature hot-rolled grain-oriented silicon steel were analyzed and compared with the hot-rolled plate by optical microscopy (OM), transmission electron microscopy (TEM), and energy dispersive spectrometry (EDS). The results show that, the surface microstructure is uniform, the proportion of recrystallization in matrix increases, and the banding textures are narrowed; the precipitates, whose quantity in normalized plate is more than that in hot-rolled plate greatly, are mainly AlN, MnS, composite precipitates (Cu,Mn)S and so on. Normalizing technology with a temperature of 1120 °C, holding for 3 min, and a two-stage cooling is a most advantaged method to obtain oriented silicon steel with sharper Goss texture and higher magnetic properties, owing to the uniform surface microstructures and the obvious inhomogeneity of microstructures along the thickness. The normalizing technology with the two-stage cooling is the optimum process, which can generate more fine precipitates dispersed over the matrix, and be beneficial for finished products to get higher magnetic properties.
Key words: low temperature grain-oriented silicon steel; normalizing cooling process; microstructure; precipitate; magnetic property