The current work aims to investigate the impact of microstructural and physical mechanisms on the macroscopic behavior and ductility of single-phase steels. For this purpose, an advanced multiscale model, accounting for intragranular microstructure development and evolution, is coupled with a formability limit criterion based on bifurcation theory. The overall response for polycrystalline aggregates is obtained from a large-strain elasticplastic single crystal constitutive law, using a self-consistent scale-transition scheme. This approach takes into account essential microstructural aspects such as initial and induced textures, dislocation densities, softening mechanisms so that the behavior during complex loading paths is properly described. Focus will be placed here on the relationship between intragranular microstructure of B.C.C. steels and their ductility. The model allows interesting qualitative study in terms of formability limits for various dislocation networks, during monotonic loading tests applied to single-phase steels, with the aim of helping in the design of new materials.