Influence of annealing on microstructures and mechanical properties of cold-rolled FeSiCrNi high silicon steel thin sheet

A novel cold-rolled Fe-6.5Si-2Cr-12Ni (wt.%) high silicon steel thin sheet with a thickness of 0.2 mm is subjected to annealing at various temperatures including 800, 900, 1000 and 1100°C, where microstructures and mechanical properties of annealed high silicon steel thin sheets are studied. The results show that with increasing annealing temperature, morphology of grains is gradually transformed from the equiaxed grains to the lath structures, where acicular ferrite is dominant. In addition, the γ-fiber, α-fiber and λ-fiber textures exist in FeSiCrNi high silicon steel thin sheets undergoing annealing at high temperatures, and intensity of γ texture progressively decreases and intensity of λ texture increases as annealing temperature increases. Tensile strength and elongation of the annealed high silicon steel thin sheets gradually decrease with increasing annealing temperature. Especially, high silicon steel thin sheet annealed at 800°C possess the highest tensile strength and elongation, where tensile strength is about 1468 MPa and elongation is about 10%. A combination of high strength and excellent plasticity for the annealed high silicon steel thin sheet results from the finer recrystallized grains as well as the lower content of ordered phase.