Effect of vanadium phase on the properties of steel 16G2AF

1. The composition of vanadium phase depends on the nitrogen and vanadium concentrations in steel 16G2AF. With a ratio of nitrogen and vanadium close to stoichiometric and a small quantity of excess nitrogen, vanadium nitride is precipitated. The amount of nitrogen in carbonitrides increases with the nitrogen content of the steel. 2. Vanadium carbonitride with a relatively low nitrogen content (2–5%) is precipitated in grain boundaries to a greater extent than vanadium nitride which leads to a reduction of the fracture toughness of steel 16G2AF with vanadium carbonitride in comparison with the steel with vanadium nitride.