Vanadium Microalloyed 0.25C Cast Steels Showing As-Forged Levels of Strength and Ductility

Application of cast steels instead of hot forged or rolled ones will significantly decrease manufacturing costs and the final product price. However, low levels of mechanical properties in cast steels, especially ductility, can slow down the substitution of forged and rolled steels with the cast. In the present work, the authors study the effect of 0.01-0.12wt% vanadium additions on the microstructure and mechanical properties of 0.25wt%C cast steels. The yield stress, ultimate tensile strength, and elongation to failure in the studied cast steels are 730-750MPa, 955-1002MPa, and 12.3-21.5%, respectively, which correspond to those in hot forged and rolled steels with similar compositions. So, high property values in the 0.25wt%C cast steels are shown here for the first time. The simultaneous increase in strength and ductility with an increase in V content follow a decrease in pearlite fraction, interlamellar spacing, and average pearlite area size; an increase in amount of degenerated pearlite; an increase in V-rich particle volume fraction and number density in ferrite and pearlite; the occurrence of interphase precipitation (in 0.12wt%V steel), and an increase in dislocation density in ferrite and pearlite.