Research on the Microstructure and Properties for Nb-Contained Cold-Rolling High Strength Steel Sheet

high strength high plasticity high beneficial textile cold-rolling steel with 540MPa tensile strength 27% elongation 1.67 (111) textile index is developed in industry. The experimental results show that the ferrite fine grain around 5ilm supports the properties of both high strength and plasticity, while the ferrite with percentage more than 90% leads to high elongation, and the large number second precipitation phase NbC with uniform fine size around lOnm is helpful to fine ferrite grain and form strong(111)textile fiber.