The influence of electron-beam welding parameters on heat-affected-zone microfissuring in INCOLOY 903

摘要: The microfissuring in the heat-affected zone (HAZ) of electron-beam-(EB-) welded thermomechanically processed INCOLOY 903 has been studied with a view to reducing incidence and obtaining better understanding influence EB welding parameters on it. For given heat material, susceptibility quantitatively related shape weld pool. Fractional factorial experimental study showed that reduction speed an increase current for input would minimize HAZ alloy. It was observed lower travel speeds, bccause shallower temperature gradients HAZ, amount liquated grain boundary area is less, thus leading decreased microfissuring. Considerable coarse boundaries warm-worked grains. microfissures appeared initiate regions slightly removed from fusion line. Minimal fine recrystallized These boundaries, however, had thickened appearance formation Nb-enrichedy phase by process liquid film migration (LFM). origin suggested be due constitutional liquation preexisting primary carbides (partial), MC carbides, MNP-type phosphides. substantial occurrence LFM minimizes decreasing total range solidification also enabling solidify without low-melting terminal eutectic reaction.