0.04Nb)have been studied by using carbon extraction replica technique.Results showed that size of most second phase particles in parent metal was ≤30 nm with average size 19.70 nm; there was a lot of residual carbo-nitride particles in CGHAZ of which the average size increased to42.78 nm
and the shape of residual particles changed from irregular morphology in parent metal to cubic in CGHAZ in which the Ti content obviously increased; and most of carbo-nitride particles in weld dissolved
the TiO formed in bath combined with other deoxidising and desulphurizing products to form large scale inclusions and the inclusions and second particles containing Nb