Effect of vanadium on the mechanical properties, phase composition, and structure of low-pearlite steel

Conclusions

• 1. The first additions of vanadium up to 0.04% in low-pearlite steel of the 09G2 type lead to larger amounts of dispersed phases due to the formation of V(CN), which promotes ferrite grain refining.

• 2. With increasing amounts of vanadium over 0.04% the quantity of V(CN) increases due to the smaller quantity of nitrogen bound with A1N and carbon bound with iron (Fe₃C).

• 3. When the vanadium content is raised from 0.04 to 0.26% there is a constant change in the stoichiometric formula of vanadium carbonitride from V(Co.6No.4) to V(Co.9No.1).

• 4. The first addition of 0.04% V favors a substantial reduction of the ductile-brittle transition temperature and higher fracture toughness of the steel. With increasing amounts of vanadium over 0.4% the fracture toughness decreases and the ductile-brittle transition temperature rises.