The effect of weld thermal conditions in commercial 22 Cr duplex stainless steel were investigated in terms of the microstructure and impact properties of heat affected zone, and susceptibility to solidification cracking of the weld. Microstructures were systematically produced using thermal simulation and gas tungsten arc welding (GTAW). Simulated HAZ microstructures were produced by heating samples above the ferrite solvus temperature and cooling in the range from 2.2 to 67°C/sec. The ferrite content of the simulated HAZ varied within 10% under the given weld thermal conditions. Charpy V-notch impact properties of these microstructures revealed that the ductile-brittle transition temperature, _vT_rs, remained at a constant level of –50°C. HAZ precipitates such as Cr-rich nitrides, intermetallic phases and the ferrite content was observed in GTA welds with heat inputs of 4.6 to 42 kJ/cm. Cr-rich nitrides were precipitated in the HAZ at the lowest heat input, however, no other preciptates such as chi and sigma phases not observed at above 6 kJ/cm. The ferrite content of the GTA weld HAZ was less than 60% at all heat inputs. The appropriate ranges of heat input and HAZ cooling rate are examined in the context of microstructures and impact properties. The susceptibility to solidification and liquation cracking of the weld was evaluated using the Varestraint hot cracking test with 1.0~5.0% strain conditions. The susceptibility to solidification cracking of duplex stainless steel weld was similar to 309 S under more than 2.0% strain, but between that of 310 S and 316 L. Fractographic studies of the solidification crack surface in duplex stainless steel, showed both dendrite and flat columnar topographies. Liquation cracking of the weld however, was not observed in either duplex stainless steel or 316 L.