## 3 Results
In the case of the sample annealed for 12 h, only larger carbide precipitates are visible in the material's microstructure (Figure 5d-f). The microstructural documentation of the material facilitated a stereological analysis of the different heat treatment variants. The analysis focused on the average cross-sectional area of the carbides, their shape factor, and their volume fraction. The shape factor of the carbide was calculated as the ratio of the carbide's area to the area of the circumscribing circle. Particles with a shape factor greater than 0.6 were considered spherical. Additionally, the average size of pearlite colonies and the average interlamellar spacing in the pearlite were analyzed. The results of the stereological analysis for the investigated material are presented in Table 4.  
Figure 4: Surface of samples after tribological testing, area of abrasion, (**a**)—4 h-100 N-2000 s; (**b**)—4 h-100 N-4000 s; (**c**) 4 h-150 N-2000 s; (**d**) 8 h-100 N-2000 s; (**e**)—8 h-100 N-4000 s; (**f**)—8 h-150 N-2000 s; (**g**)—12 h-100 N-2000 s; (**h**)—12 h-100 N-4000 s; (**i**)—12 h-150 N-2000 s.  
The analysis indicates that, with increasing annealing time, the average size of the carbides increases. The largest particles are observed in the sample annealed for 8 h. For the 12 h annealed sample, the average carbide area is smaller than that of the 8 h sample but larger than that of the sample subjected to the shortest annealing time. As the annealing time extends, the average volume fraction of carbides present in the material decreases. Examining the changes in the shape factor of the studied materials, it can be observed that all materials exhibit carbide precipitates with a nearly spherical cross-section. However, the shape factor is lowest for the sample annealed for 8 h. The matrix analysis of the material revealed that, with an increase in annealing time, there is a rise in the size of pearlitic colonies. This increase can be linked to a reduction in the volume fraction of the observed precipitates. As their volume fraction decreases, there are fewer particles available to act as nucleation sites for pearlitic colonies, resulting in larger average colony sizes. Additionally, the annealing time affected the average actual interlamellar spacing in the pearlite. A decrease in this parameter is observed with longer annealing times (Table 4). The stereological analysis of the material's microstructure was complemented by an examination of the carbide size distribution. Figure 6 illustrates the frequency distribution histograms for carbide sizes. The range of carbide sizes was restricted to areas of up to 1 \(\upmu\)m\({}^{2}\). Carbides larger than 1 \(\upmu\)m\({}^{2}\) were classified separately. Additionally, labels indicating the percentage share of each size class within the total population of precipitates have been included above the bars. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \begin{tabular}{c} **Annealing** \\ **Time, h** \\ \end{tabular} & \begin{tabular}{c} **Average Particle** \\ **Size, \(\upmu\)m\({}^{2}\)** \\ \end{tabular} & \begin{tabular}{c} **Volume Fraction** \\ **of Carbides, \%** \\ \end{tabular} & \begin{tabular}{c} **Shape Factor of** \\ **Particle** \\ \end{tabular} & \
\begin{tabular}{c} **Perlite Colony** \\ **Size, \(\upmu\)m\({}^{2}\)** \\ \end{tabular} &
\begin{tabular}{c} **Interplate Distance in** \\ **Perlite, \(\upmu\)m** \\ \end{tabular} \\ \hline
4 h & 0.44 \(\pm\) 0.67 & 9.26 \(\pm\) 1.31 & 0.93 \(\pm\) 0.01 & 25.19 \(\pm\) 1.50 & 0.20 \(\pm\) 0.03 \\ \hline
8 h & 1.16 \(\pm\) 1.21 & 7.76 \(\pm\) 1.33 & 0.87 \(\pm\) 0.01 & 29.93 \(\pm\) 1.54 & 0.17 \(\pm\) 0.05 \\ \hline
12 h & 0.89 \(\pm\) 0.89 & 5.84 \(\pm\) 0.92 & 0.93 \(\pm\) 0.01 & 31.16 \(\pm\) 2.23 & 0.16 \(\pm\) 0.05 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Results of the stereological analysis of the investigated samples. Figure 5: Microstructure of the investigated material: (**a,d**)—4 h annealing; (**b,e**)—8 h annealing; (**c,f**)—12 h annealing.