Grain Refinement in V-N Steel

The size of austenite and ferrite in V-N steel, V-steel and C-Mn steel in the same condition was investigated. The results show that grain refinement effect in V-N steel is most remarkable. The further analysis indicates that the precipitation of V(C,N) in austenite is the vital factor of grain refinement in V-N steel. On the one hand, the precipitation of V(C,N) in austenite can prevent austenite grain growth; on the other hand, V(C,N) can promote the nucleation of ferrite by inducing formation of intragranular ferrite as nucleus, which increases nucleation ratio markedly.