Effect of Decarbonization Annealing Temperature on Microstructure, Texture and Magnetic Properties of Grain-oriented Pure Iron

In order to promote the manufacturing process of grain-oriented pure iron to obtain higher magnetic properties, the cold-rolled sheet of grain-oriented pure iron made in the laboratory was taken as the research object, and the decarburization annealing experiments were carried out. Metallographic microscope, electron backscatter diffraction scanning electron microscope, and magnetic property measurement instrument were used to characterize its microstructure and properties. The effect of decarburization annealing temperature on the primary recrystallization microstructure, texture and magnetic properties of high temperature annealed sample of grain-oriented pure iron was investigated. The results show that there are still some small grains in the decarburization annealing sheet, most of which are concentrated near the central region of the sample. When the decarburization holding time is 2 min and the annealing temperature is 775, 800 ℃, the average grain sizes are 6.12, 6.39 μm, respectively, due to the partial aggregation of small grains, and the average grain size is 6.85 μm at 825 ℃. The main texture type of the decarburized sheet at different temperatures is approximately the same. The main textures on the α orientation line are distributed around 112−223<110>, and the main textures on the γ orientation line are distributed around 111<110> and 111<112>. The intensity of 111<112> texture is always the highest, and the intensity of other textures doesn’t change much with the increase of decarburizing annealing temperature. The finished product annealed at 825 ℃ for 2 min show the best magnetic induction, of which B₈₀₀ is 2.00 T and B_{10 000} is 2.13 T. There are “isolated” points in the finished product, which have texture types of 110<112>−<115>. The generation of “isolated” is related to the lower homogenization temperature, and the inhibiting agent particles in the ingot aren’t completely dissolved, resulting in insufficient inhibiting ability. So, the grains with 110<112>−<115> orientations grow to different extents during high temperature annealing. Furthermore, the presence of “isolated” suggests the potential for further enhancement in the magnetic induction of grain-oriented pure iron.