THE FINE STRUCTURE OF Nb AND V PRECIPITATES IN Nb-V STEEL

The precipitation of Nb and V in Nb-V steel has been investigated by means of STEM and EDAX. It Was found that a complex ordered carbonitride is formed on hot-rolling and continuous cooling by the precipitation of Nb and V together with C and N in which the contents of Nb and V are changeable. Its concentration ratio, C_(Nb)/C_v, decreases with the decrease of the grain size precipitated. The stoichiometric formula of the precipitate may be (Nb, V) (C_(1-x), N_(1-y)). Electronic microscopic observation revealed that both the morphology characteristics and the crystallographic orientation of the precipitate seem to be identical with ones either in the Nb- or V-steel.