저널

The cost for maintenance (replacement cost) of Ni-superalloy components in plant industry is very expensive because of high unit price of INCONEL 718. A development of repairing technology using kinetic spray process can be very helpful for reducing the maintenance cost. However, it is very difficult to produce well-deposited INCONEL 718 layer showing high interfacial bond strength via kinetic spraying. Thus, INCONEL 718 was deposited on SCM 440 substrate and the interfacial properties were investigated, in order to elucidate the cause of hindrance to the bonding between INCONEL 718 layer and SCM 440 substrate. As a result, it was revealed that the dominant obstacle to the interfacial bonding was excessive compressive residual stress accumulated in the coating layer, resulting from low plastic-deformation susceptibility of INCONEL 718. Nevertheless, the bonding state was enhanced by the post heat-treatment through relieving the residual stress and generating a diffusion/metallurgical bonding between the INCONEL 718 deposit and SCM 440 substrate.

INCONEL 718;kinetic spray process;bonding;residual stress;heat-treatment;