Study of strength characteristics of nitrated gear wheel

The linear static characteristics of a stainless steel gear wheel after chemical-thermal treatment (nitriding) have been studuied. As a result of nitriding, hardness of the product and its wear resistance increase. An experiment showed that the optimal temperature for the formation of a nitrided layer with hardness 11740-12003 MPa for corrosion-resistant heat-resistant steel of grade 12X18N9T was 570-590 °C, with the nitriding time 48 hours. However, too high hardness of the nitrided layer leads to an increase in brittleness of the gear wheel, so in this case the deep surface treatment may be required during grinding or polishing. It is shown that after nitriding, the steel under study has a homogeneous structure with clearly defined transition layers, average thickness of the nitrided layer is 60-90 microns. The stress-strain state of the product before and after nitriding, which determines the internal stresses and the deformation of a wheel tooth, shows that the static characteristics are approximately equal. However, the nitrided wheel has higher hardness, a higher safety margin and a lower tendency to strain under high loads.