|About this Abstract
||2020 TMS Annual Meeting & Exhibition
||Characterization of Minerals, Metals and Materials
||Fatigue Resistance of Low Pressure Nitrided Cr-Mo Low Alloy Steels
||Donato Firrao, Enrico Morgano, Graziano Ubertalli, Angelo Brunelli, Davide Sabena
|On-Site Speaker (Planned)
Fatigue resistance of steel parts can be improved by nitriding, the more the deeper is the layer affected by nitrogen diffusion, as stated by the Lessell-Firrao law. Low-pressure nitriding has been applied to wheel's hubs fabricated with a quenched and tempered Cr-Mo low alloy steel. N diffusion depths have been compared to similar results obtained with the same type of automotive parts subjected to classical gas nitriding. 12 h total low-pressure treatment time provided an almost 100% increase of hardened depth over 40 h gas nitrided parts. Both treatments allowed to reach an adequate fatigue life, whereas induction hardened parts did not. X-ray diffraction analysis provided phase constitution of top converted layers in both nitriding cases. A rationale based on the effect of early treatment stage top layer formation has been developed.