Torque loss characterization of an FZG-C Type C-GF gear rebuilt via Direct Laser Deposition

Direct Laser Deposition (DLD) is a metal additive manufacturing process that can potentially extend the useful life of gears. The DLD repair process proved to be applicable in several cases. However, concrete applications of DLD for gears are still limited to teeth reconstruction without considering functional applications. This research evaluates the torque loss of an FZG-C Type C-GF gear rebuilt using DLD under actual operation. The study details the strategy used to restore a case-hardened 16MnCr5 FZG-C Type C-GF gear with a combination of Inconel 625 for the tooth core and AISI 431 as a superficial coating, and it compares its performance with a base material pinion (not repaired). This work extends the analysis performed in a previous attempt and presents a much more comprehensive characterisation. The results include visual inspection, base tangent length assessment, double-flank working test, torque loss and microhardness measurements. The DLD teeth showed very good adhesion to the base material during the tests and similar torque loss behaviour to the reference.