## 4 Results and Discussion  
### Experimental Results  
An experiment was carried out to investigate how different loads, sliding times and sliding speeds impacted the friction coefficient and wear rate of ductile cast iron in a ferrite microstructure. Table 3 shows the exact specifications for these microstructures.  
In Figure 6, the extent to which the friction coefficients (COF) of the three specimens change as the sliding duration increases can be seen. Comparisons were made between specimens 2 and 3 to identify differences in how the COF behaves when the sliding speed changes (from 70 to 114 cm/s) and the load is kept constant (52.015 N). The findings show that there was a reduction in the COF when the sliding speed increased and the load remained constant. This can be summarized by saying that increased sliding speed causes the temperature between the two sliding surfaces to rise. Thus, at high sliding speeds, friction has less of an impact on the specimen's surface than it does at low sliding speeds.  
Additionally, Figure 6 compares specimen 2 and specimen 3 at sliding speed (70 to 114) cm/s and under constant load (52.015 N) in order to illustrate the behavior of wear rate (WR). It is evident that the wear rate dropped as the sliding speed increased. This can be explained by stating that friction caused the temperature between the two sliding surfaces to rise as the sliding speed increased. When sliding at a high speed, less heat is lost through the metal than when moving slowly, which promotes the development of an oxide layer that slows the rate of wear.  
The effect of the applied load on the wear rate can be determined by fixing other parameters and varying the load. This is clearly demonstrated when comparing the behavior of specimen 1 and specimen 2 in Figure 6, which shows that the wear rate increases with the increase in the applied load. The reason for this is due to the increase in the plastic deformation that occurs between the two surfaces,  
Figure 6: Differences in the friction coefficients and wear rates based on sliding time.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Type** & **No. of Nodules (mm2)** & **Diameter (\(\upmu\))** & **Load (N)** & **Sliding Speed (cm/s)** \\ \hline Spec.1 & 355 & 20.9 & 17.338 & 70 \\ Spec. 2 & 335 & 20.9 & 52.015 & 70 \\ Spec. 3 & 335 & 20.9 & 52.015 & 114 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Microstructure test characteristics.  
area of contact. Furthermore, the high load leads to a strong metal contact that makes the force required to cut the connected protrusions higher than the strength of connecting metal atoms.  
Figure 7 shows the impact of the microstructure produced by heat treatments (annealing and isothermal processes) on the wear rate. The sliding time was the variable parameter, while the other parameters (applied load and sliding speed) were kept constant. It is clearly shown in the figure that the bainite structure produced a lower wear rate than the ferrite structure. This is due to the fact that the resistance of the bainite structure's surface layers to plastic deformation is higher than the ferrite structure because of the bainite structure's higher hardness (320 HV). On the other hand, the ferrite structure's lower hardness (145 HV) generates a plastic flow and increases the size of the contact area. It also causes weak resistance due to its softness and readily adheres to the opposing surface [25].