The effect of chemical composition and processing parameters on the formation of acicular ferrite and/or bainite has been investigated.In particular,this paper deals with the influence that N through its combination with V,as V(C,N) precipitates,has on the decomposition of austenite.Likewise,the intragranular nucleation potency of V(C,N) precipitates is analyzed through the continuous cooling transformation diagrams (CCT) of two C-Mn-V steels with different contents of N.Results reported in this work allow us to conclude that acicular ferrite can only be achieved alloying with vanadium and nitrogen,meanwhile bainite is promoted in steels with a low level of nitrogen.It is concluded that higher strength values are obtained in acicular ferrite than in bainitic steel but a similar brittle-ductile transition temperature (BDT),and lower values of impact absorbed energy (KV) has been recorded in nitrogen-rich steel. The effect of chemical composition and processing parameters on the formation of acicular ferrite and / or bainite has been investigated. In particular, this paper deals with the influence that N through its combination with V, as V (C, N) precipitates, has on the decomposition of austenite. Thumbwise, the intragranular nucleation potency of V (C, N) precipitates is analyzed through the continuous cooling transformation diagrams (CCT) of two C-Mn-V steels with different contents of N. Results made in this work allow us to conclude that acicular ferrite can only be achieved alloying with vanadium and nitrogen, meanwhile bainite is promoted in steels with a low level of nitrogen. It is concluded that higher strength values ​​are obtained in acicular ferrite than in bainitic steel but similar brittle- ductile transition temperature (BDT), and lower values ​​of impact absorbed energy (KV) has been recorded in nitrogen-rich steel.