Performance evaluation of railway wheels repaired through laser directed energy deposition (DED-LB)

Railway wheels and rails wear is probably one of the biggest challenges in the maintenance of transportation system. In modern high-speed trains, maintenance costs can represent almost a third of the total life costs, where the wheelset wear is one of the most common and costly phenomena. In view of this problem, in the present research the feasibility of employing the Additive Manufacturing (AM) process known as laser Directed Energy Deposition (DED-LB) is analyzed as a novel alternative to current wheel repair procedures based on material elimination. For this purpose, test parts are extracted from real wheel´s treads and filler material is deposited on its surface. AISI 4140, AISI H13, and EuTroLoy 16606 powder steels are tested. In all cases the resulting metallurgical quality of the filler material is evaluated, as well as the adhesion to the base material of the wheel. Besides, the mechanical performance of the deposited coating is also evaluated, focusing on hardness and wear resistance. Once the process parameters are optimized, excellent adhesion is achieved in all the tested materials and defect free coatings are obtained, which ensures the feasibility of repairing railway wheels through DED-LB. EuTroLoy 16606 demonstrates the most favorable mechanical performance for full-surface coating applications, due to its lower wear rate under testing conditions. In contrast, AISI 4140 is a better choice for partial repair operations, as its mechanical properties closely align with those of the original ER9 wheel material. This compatibility ensures better structural continuity and minimizes the risk of mismatch-related failures in localized repairs.