Repair and Remetalization of Naval Journal Bearings using DED-Lw

Journal bearings constitute an essential component of naval machinery and, at the same time, pose a persistent challenge for designers, who often regard them as a “necessary evil” because of the continuous wear they experience and the associated energy consumption. The failures observed in these components are most commonly related to cavitation erosion, inadequate lubrication, or defects introduced during manufacturing and subsequent assembly. As a consequence, journal bearings frequently require either complex repair procedures or complete replacement, both of which involve substantial costs and extended downtime. This makes their maintenance particularly critical in naval applications, where accessibility constraints and operational demands further amplify economic and logistical impacts. The aim of this work is to develop an innovative solution based on Direct Energy Deposition using laser and wire (DED-Lw) technology for the repair of journal bearings through the deposition of an antifriction Babbitt alloy, mainly composed of 89 wt.% Sn and 3 wt.% Cu. In a first stage, the process is investigated at the specimen level, with an analysis of the wear behaviour and the adhesion of the deposited material to the substrate. Subsequently, the feasibility of applying the process to bearings subjected to actual operating and service conditions is assessed. After a rigorous inspection and repair procedure, the performance of the proposed solution is evaluated under operating conditions representative of a realistic naval scenario, demonstrating the viability of this technology for extending the service life of journal bearings in the naval industry. This development represents a significant advancement in reducing costs and lead times associated with maintenance operations, as well as a substantial reduction in vessel downtime, thereby contributing to the optimisation of the performance and reliability of propulsion systems and auxiliary machinery on board.