## 6 The Structure of Cast Iron after Introducing Tungsten and Its Resistance to Abrasive Wear

Table 3: Chemical composition of the investigated cast iron. Figure 8: SEM microstructure of high-aluminum cast iron with the addition of tungsten (**a,b**) and EDS X-ray microanalysis of carbide precipitation with a chemical analysis of tungsten carbide (**c**). Figure 9: SEM microstructure (**a**) of high-aluminum cast iron with the addition of tungsten marking for the chemical composition of the area: no. 1 tungsten carbide, no. 2 metal matrix and graphite in the structure and its EDS X-ray microanalysis (**b**). Figure 11: SEM microstructure of high-aluminum cast iron with the addition of tungsten with a chemical composition analysis for no. 1 oxide particle. Figure 10: SEM microstructures of high-aluminum cast iron with the addition of tungsten (**a**) graphite in the structure and its EDS X-ray microanalysis (**b**). Figure 11 shows the SEM image of samples with a porous metal matrix (the result of etching and preparation of the sample surface). The metal matrix of the alloy ferrite is 20.5 mass % to 20.7 mass % aluminum. In addition, the structure includes particles of sulfide and oxide conglomerates with aluminum. As already mentioned, the presence of graphite was also revealed in the microstructure of the obtained cast iron, which is confirmed by the Fe-Al-C triple system diagram generated by the Thermo-Calc program shown in Figure 2. The fracture of the sample is shiny, fine-grained, and compact. There is also no visible systolic cavity. Then, an abrasion test was carried out on the Miller machine. The applied test method is used to compare the resistance to abrasion of construction materials of different hardness or materials covered with a layer of ceramic material (e.g., nitrides). The test consists in making at least three attempts, each in not less than 2 h. A 16-h series of 4 four-hour runs is recommended. This makes it possible to determine the wear curve. Figure 12 shows the microstructures after the full abrasion test on the Miller machine. The mass wear rate V\({}_{\text{w}}\) was calculated, as determined by the tangent of the angle of inclination of the tangent line to the curve in the second hour of the abrasion wear test [15]:  
\[\text{V}_{\text{w}}=\text{A}\cdot\text{B}\cdot 2^{(\text{B}-1)}. \tag{5}\]  
where: A, B--constants determined by the method of least squares. Table 4 presents the results of abrasion wear tests expressed as a mass loss of the sample. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Sample No.**} & \multirow{2}{*}{**Starting Weight**} & \multicolumn{4}{c}{**Weight of the Sample in Grams**} \\  & & & **after the Time of** & & \\ \cline{3-6}  & & **4 h** & **8 h** & **12 h** & **16 h** & \\ \hline (A) [15] & 19.75 & 19.52 & 19.35 & 19.16 & 18.90 & 0.05537 \\ \hline (B) & 18.22 & 18.12 & 18.05 & 17.97 & 17.89 & 0.02300 \\ \hline (C) [15] & 15.64 & 15.55 & 15.45 & 15.36 & 15.28 & 0.02299 \\ \hline \multirow{3}{*}{(D)} & \multicolumn{4}{c}{No abrasive wear test results were obtained} \\  & & & due to the high slip of the specimen & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The results of the abrasion wear test. Figure 12: SEM images of high-aluminum cast iron with the addition of tungsten (**a**) and SEM images of high-chromium cast iron (**b**) after a full abrasion test with the Miller machine. For high-chromium steel (A), the weight loss was the greatest, i.e., 0.85 g [15]. For chromium cast iron (B)--with the chemical composition [% mass]: 3.35% C; 1.5% Si; 0.63% Mn; 21.10% Cr, the weight loss of the sample was 0.33 g and for sample (C) of high aluminum cast iron with vanadium addition was 0.36 g.