Abstract: The technology for automatic submerged arc welding of duplex stainless composite steels,the choice of welding consumables and its weldability have been researched.The result shows that its weldability is good when the content of delta frerrite in clad weld is at the range 35%~45%.In order to obtain a smaller rate of dilution,good appearance of weld and to prevent a large amount of martensite and other hardening phases from occuring near the bond line of the base metal weld,smaller welding parameters and single-pass welding have been adopted for the transition layer weld.The welded joint of HII/X2CrNiMoN22.5 duplex stainless composite steels has good mechanical properties and the clad weld has good resistance to intercrystalline corrosion and resistance to stess corrosion.The suitable welding consumables and the best technology of automatic submerged arc welding have been presented to produce pressure gasifiers in this paper.