Texture, microstructure and mechanical properties of aluminum modified ultra-pure 429 ferritic stainless steels

摘要

Effect of aluminum on texture, microstructure and mechanical properties of ultra-pure 429 ferritic stainless steels has been investigated. Average grain size after annealing slightly increases with increased aluminum content because of the decreased recrystallization temperature and reduced area fraction of inclusions. Recrystallization texture of the surface and center layers evolves from α+γ-fiber to full γ-fiber, and the maximum intensity of γ-fiber increases with addition of 0.16 wt.% aluminum. However, the γ-fiber of {111} <1-21> shifts to {223} <3-62> and both the intensity of {111} <-1-12> and {111} <- 2-35> decreases when aluminum content is further increased to 1.51 wt.%. The maximum texture intensity of γ-fiber in thickness direction can be significantly improved in steel with 0.16 wt.% aluminum but not in steel with 1.51 wt.% aluminum. Increased aluminum content benefits room temperature tensile properties, and steel with 0.16 wt.% aluminum exhibits plastic strain ratio of about 1.62. The TiN and MgO·Al_2O_3-TiN particles with a slightly increased average size and decreased area fraction may not suppress the growth of recrystallized grains and contribute to increased intensity of γ-fiber texture. The steel modified with 0.16 wt.% aluminum exhibits excellent formability due to the appearance of the strong γ-fiber texture.