2008 Volume 26 Issue 3 Pages 242-251
In order to investigate the solidification cracking susceptibilities of SUS347H weld metal containing high niobium and carbon contents, it is important to analyze the crystallization behaviors of not only δ and γ phases but also niobium carbide during welding solidification. In the present study, the behavior of the phase selection for γ, δ phase and niobium carbide on Fe-18%Cr-0.2%C-1%Nb-(5-12)%Ni weld metals during welding solidification was investigated by the developed in-situ observation technique of welding solidification process using synchrotron radiation. On the other hand, to evaluate the micro segregation in liquid phase on SUS347H weld metal during welding solidification, which has influence on the solidification cracking susceptibility, the numerical model to calculate the micro segregation in liquid phase considering the crystallization of γ, δ and niobium carbide was developed. As a result, the validity of the developed numerical model was supported by the comparison with experimental results by in-situ observation of welding solidification process on Fe-18%Cr-0.2%C-1%Nb-(5-12)%Ni weld metals. Furthermore, it was found that the solidification cracking susceptibilities of Fe-18%Cr-0.2%C-1%Nb-(5-12)%Ni weld metals predicted by the developed numerical model coincided with the experimental results evaluated by trans varestraint test.