Studies on microstructure and mechanical properties of keyhole mode Nd:YAG laser welded Inconel 625 and duplex stainless steel, SAF 2205

This article addresses the metallurgical and mechanical properties of Nd:YAG laser welded Inconel 625 and duplex stainless steel SAF 2205. Keyhole plasma mode laser welding was adopted to obtain the joints. Microstructure studies showed slight grain coarsening at the heat affected zone of Inconel 625. Line mapping and elemental mapping analysis were carried out at the weld interface and in the fusion zone to examine the elemental migration as well as the composition of the phases present in these regions. The fusion zone microstructure showed the presence of Nb, Mo rich Laves phase segregated at the interdendritic arms. Tensile studies corroborated that an average joint strength of 820 MPa has been displayed by these weldments, which was almost equal to one of the parent metals, SAF 2205. It is evident from the charpy v-notch studies that the impact toughness of these laser weldments was found to be 10 J and this low toughness could be reasoned out to the formation of Mo rich phases. The structure–property relationships of these weldments have been addressed in detail and the outcomes of the study will be highly useful for marine and geothermal applications.