Effect of Plasma Nitriding Technology Parameters on Working Surface Quality Gears made of SAE 5120 Steel

This article is to provide the findings of a study on the optimization of plasma nitriding technology parameters for a hypoid gear working surface made of SAE 5120 material.

The experiment of the nitriding was conducted in an Eltropuls H045 × 080 plasma nitriding device. The second-order planning with 27 experiments was implemented, varying the permeation time (h), the permeation temperature (TL), and the gas permeation concentration (G1).

From the experiment, the set of optimized input parameters was derived: permeation time: 6.14 h; permeation time: 533.8 h; and gas permeation concentration: 5.7 l/h.

The finding revealed that the temperature has a positive influence on all three parameters: hardness, thermal deformation, and roughness, but the roughness tends to slightly decrease. The concentration (flow rate) of the gas mixture has the weakest impact on the parameters, except for thermal deformation. This process is recommended for heat treating the gear box made of SAE 5120 steel.