Influence of tribological parameters on S335 steel filing Ti-W-N in dry sliding wear: Prediction model and sliding condition optimization

In the present paper, dry sliding wear tests were performed on S335 steel coated with hard layer (Ti-W-N) with thickness at 2 mu m at different sliding velocities (2.5 and 5 cm/s), sliding distances (9.42 and 18.80 m), and applied loads (2 and 4 N). These tests have been studied using a pin-on-disc machine, and the results are presented. Mathematical models for dynamic friction coefficient, wear volume or volume loss, and total roughness were developed using the response surface methodology (RSM). Wear mechanisms for S335 steel were characterized by scanning electron microscopy. Two wear mechanisms have been identified irrespective of the applied load: crack wear occurs at the lowest sliding distances and delamination wear occurs at the highest. Also, results indicated that by increasing the sliding velocity and sliding distance, a transition from crack wear to delamination wear occurs with a corresponding maximum in the loss of volume due to wear.