Fatigue life of laser additive manufacturing repaired steel component

Abstract

Laser cladding is an additive manufacturing process which is spreading as a valuable resource for manufacturing and repairing mechanical components that are subjected to intense wear. Advantages over conventional welding include a much lower heat input and minimal dilution, also surpassing metal spraying due to the resulting metallurgical bond. In this paper, the effect of laser cladding on the fatigue life of a 70 mm diameter component of wrought quenched and tempered AISI-SAE 4140H is assessed, along with full characterization of defects, hardness and residual stress distributions. Additionally, a theoretical fatigue crack propagation prediction model based on a fracture mechanics approach is demonstrated to provide acceptable estimated fatigue lives, and shows how the most influential process variables affect these results.