Study On Recrystallization Texture In3.0%Si Silicon Steel

Silicon steel is an important soft magnetic material in the electronic and electrical industries, and commonly used in hydroelectric power plant generators and electric motors. How to produce high quality products with low cost and high efficiency is the main development direction of the silicon manufacturing technology. Recrystallization texture is a key factor to determine the magnetic properties of silicon steels. Exploring effective control over silicon steel hot rolling, normalization, cold rolling and annealing processes to optimize the recrystallization texture is the necessary way for the development of advanced silicon technology.Cold-rolling and double-reducing processes are adopted in producing3.0%Si silicon steel thin strip in this paper. The effect of hot rolling, normalization, cold-rolling and double-reducing rate and intermediate annealing on the recrystallization textures and magnetic properties of the finished steel strips is studied by x-ray diffraction and electron backscatter diffraction (EBSD). The obtained major conclusions are as follows:(1) When3.0%Si silicon steel thin strips are made by means of cold rolling, normalization processes have significant effect on recrystallization textures. In high-temperature slab heating process, elevating normalizing temperature is beneficial to enhance cube texture, and η texture with harmful y texture are weakened. In low-temperature slab heating process, the influence of normalizing temperature on recrystallization textures is related to cold rolling reduction rate:When the reduction rate is between67%～72%, elevating normalizing temperature will enhance cube texture and weaken η texture; when the reduction rate is78%, elevating normalizing temperature will enhance cube texture, but η and y texture don’t change significantly.(2) When3.0%Si silicon steel thin strips are made by means of cold rolling, cold rolling reduction rate have significant effect on recrystallization textures. When the reduction rate is between67%-72%, increasing cold rolling reduction rate will enhance η texture in different normalization system; When cold rolling reduction rate is increased to78%, strong y texture appears in different normalization system. (3) When3.0%Si silicon steel thin strips are made by means of double-reducing, cold-rolling rate and double-reduced rate both have significant effect on recrystallization textures. When the reduction rate is between67%-72%,η texture appears in finished steel strips. When the reduction rate decreases to85%, η texture is weakened, which means the suitable cold rolling reduction rate is between67%-72%. The effect of double-reduced rate on recrystallization textures is related to the microstructures and textures in the hot bands: double-reduced rate has a wide range in partially recrystallized hot bands. When the reduction rate is between50%～70%,strong η recrystallization texture appears. On the contrary, the reduction rate has a narrow range in deformed hot bands. When the rate is50%, strong η recrystallization texture appears. And when the reduction rate increases to60%,η recrystallization texture begins to diffuse and be weaken.(4) EBSD analysis shows that:In the early stage of recrystallization, Goss nuclei are mainly nucleated in the shear bands of deformed{111}<112> grains, and then grow up gradually. But the formation of cubic texture after high-temperature annealing may be related to large grain size and no cluster phenomenon that may cause orientation pinning.