Laser cladding and wear testing of nickel base hardfacing materials: Influence of process parameters

In fast neutron reactors, some parts can be subjected to displacements between each other (as movable parts for example). On these parts, the contact areas usually need a hardfacing coating. The standard hardfacing alloy is a cobalt-base alloy (for example Stellite®6). Unfortunately, in the primary coolant circuit and on wear conditions, cobalt can be released. Under neutron flux, the stable 59Co can be transmuted into 60Co by radioactive capture of neutrons and, therefore, can contaminate the primary circuit. Therefore, it is desired to replace this cobalt based hardfacing alloy by a cobalt-free one. Previous presentations have shown the potential interest of some nickel base materials as Colmonoy® alloy. In parallel, laser cladding has been identified as a deposition process that could increase the performances of the hardfacing materials compared to the standard process (Plasma Transferred Arc Welding). In all the study, the base material is the stainless steel 316LN. In the first section of this artic...