Preparation of 316L(N) stainless steel weld joints containing 0.05 to 0.14 wt.% N and study on its microstructure and properties

AISI 316L(N) austenitic stainless steel (SS) containing 0.07 wt.% nitrogen (N) is used as structural material for high temperature components operating in sodium environment of Prototype Fast Breeder Reactor (PFBR). A study on the properties of N enhanced 316L(N) SS weld joints containing different levels of N content in the weld metal are to be carried out to optimize the N content in the weld metal for the fabrication of components. Therefore, it was decided to introduce nitrogen in the weld metal through shielding gas using robotic TIG welding machine so that 316L(N) weld metals with different N contents can be produced. Hence, 316L(N) weld metals containing various levels of N in it were produced in laboratory scale and its properties were studied. This report highlights that 316L(N) weld metal containing different levels of N using the precise binary gas mixing unit during robotic hot wire TIG welding process were successfully prepared at materials joining section (MJS). Subsequently, 316L(N) SS weld joints were prepared with N enhanced 316L(N) weld metal. The preliminary investigations showed that the N enhancement in the weld metal has pronounced effect on the solidification mode of the weld metal, microstructure and hardness. Evaluation of mechanical and corrosion properties of these weld metals are in progress to qualify the joint