Interaction of niobium and nitrogen dissolved in a molten steel on the plasma welding

Aimed at the investigation of mechanism of nitride formation during plasma welding of austenitic steels thermodynamic analysis for the processes proceeding in microvolume of welding bath has been performed. The experiment have been carried out with steel type 08kh18N10T as a base metal and welding wire of steel type 04kh20N10G2B. It has been established that drops of liquid metal of welding wire are saturated with nitrogen and transfer it to the welding bath. In welding bath niobium-nitrogen interaction occurs with niobium nitride formation. The protection of welding bath from environment is recommended as the only way to prevent nitride formation in steels alloyed with such active elements as niobium.