Dynamic response characteristics and damage mechanism of impact wear for deep plasma nitrided layer

The impact wear behaviour of deep plasma nitrided layer and its substrate (axle steel) were investigated. The nitrided layer had a 6 µm thick compound layer, and the effective case depth was 0.85 mm. Moreover, it introduced compressive residual stress with a maximum of 715.8 MPa at a depth of 511 µm. The nitrided specimens showed a lower energy absorption ratio and better impact resistance than the untreated specimens. Plastic deformation occurred in the initial test of the untreated specimens, but elastic deformation was predominant for the plasma-nitrided layer. The main wear mechanisms of the untreated samples were pitting, delamination and oxidation wear. In contrast, the plasma-nitrided specimens exhibited better oxidation resistance and slighter peeling-off than the untreated specimens. [Display omitted] •Deep layer plasma nitriding was employed to axle steel.•The impact wear behavior of the nitrided and untreated specimens was investigated.•A lower energy absorption ratio was found for nitrided sample compared to untreated one.•Deep plasma nitrided layer had a better impact wear resistance.