SEM CHARACTERIZATION OF COMPLEX PRECIPITATES IN AN AS-CAST

This article deals with the characterization of complex precipitates from commercial Nb-V-Ti microalloyed steel produced by continuous casting, using fracture surfaces from V-notch Charpy tests, and extracted precipitates. The samples were studied by means of scanning electron microscopy and X-ray energy dispersive spectroscopy, in combination with X-ray diffraction. Samples examination revealed micron size (Nb,Ti,V)(C,N) precipitates, most of them with a highly branched dendritic morphology, and Ti rich precipitates, corresponding to (Ti,Nb,V) (C, N). Also dendritic Nb(C,N) without Ti was observed. By means of the method used in this investigation, it was possible to easily reveal the precipitates, being able to fully characterize their distribution, size and morphology, and also their chemical composition and crystal structure