Welds were produced in three highly alloyed superaustenitic materials, namely UNS S32654, S34565 and R20033. These materials have very high nitrogen additions in the range 0.39 to 0.49%. Welding employed the TIG process with Ar, Ar+20%He+2%N₂ and Ar+10%N₂ shielding gas mixtures and a range of arc energy.

Pitting corrosion resistance of the welds was assessed in ferric chloride solution and linked to microsegregation of Mo and Cr in the weld metal, nitrogen loss/pickup in the weld metal and intermetallic phase precipitation in both weld metal and HAZ. Results indicated that weldments with excellent pitting corrosion resistance, approaching that of the parent steel, could be produced without filler addition, although use of overalloyed nickel base filler gave highest pitting resistance. Microsegregation and nitrogen loss occurred to similar extents in all three materials and nitrogen loss was a significant problem when TIG welding these steels. A modified pitting resistance equivalent expression is proposed, linking corrosion resistance of weld metal to its composition.