Effect of welding position on properties of duplex and superduplex stainless steel circumferential welds

The influence of welding position on properties of duplex and superduplex stainless steel welds was studied. Circumferential pipe welds were produced using mechanised gas metal arc welding in flat position, vertical up position and overhead position. Dilution, corrosion resistance, mechanical properties, microstructural features and weld imperfections were assessed and related to the welding position. Welds produced in flat and vertical up positions were less likely to produce porosity than those welded in overhead position, whilst underfill was not observed in overhead position welds. All the duplex pipe welds passed the corrosion test regardless of the welding position and showed sound microstructures. Under fixed arc energy conditions, welds produced in vertical up position showed the lowest dilution values whilst welds in flat position showed the highest. Excellent impact toughness values and cross tensile values were found regardless of the welding positions. Whenever possible, flat position is recommended as welds showed less proneness to porosity. Vertical up position is recommended as the second best choice.