Abstract: The effect of hot rolling heating temperature on microstructure and precipitates of 3.0 % Si nonoriented silicon steel was studied. The results showed that there was a structure gradient along the thickness direction of the hot rolling plate, and spherical and irregular precipitates were distributed in the grains. With the increase of the hot rolling heating temperature, the width of the fibrous deformation zone in the middle layer became narrow. When the temperature increased to 1 150 ℃, the number of AlN precipitates less than 100 nm increased. After normalizing at 900 ℃, the microstructure of the hot rolled plate was completely recrystallized, and the homogeneity of the microstructure was improved, the precipitates were aggregated and coarsened. With the increase of the hot rolling heating temperature, the average grain size of the normalized hot rolled plate decreased, and the number of precipitates more than 100 nm increased, in addition, the number of AlN, AlN + Ti composite precipitates in the range of 20-100 nm increased gradually.

Key words: non oriented silicon steel, hot rolling, microstructure, precipitate