Studies on the pore formation in super duplex stainless steel welds

When welding super duplex stainless steels, a non-admissible pore formation can occur even if recommended processing guidelines are strictly followed. To investigate this phenomenon and to determine the influencing factors, different bead-on-plate welds were produced using gas metal arc welding and submerged arc welding. The welding consumables, the shielding gas, and the welding flux were varied. Additionally, the influences of heat input and interpass temperature were examined. The studies have shown that the shielding gas, the welding flux, and the filler metal have great influence on the pore formation. Even small variations in the chemical composition of the welding consumables lead to different results. In addition, the ferrite number and the chemical composition of the bead-on-plate welds strongly depend on the used shielding gases and filler metals. Furthermore, it became clear that the porosity of the weld metal can be affected by the welding speed.