## 3 Results
\begin{tabular}{l c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{2}{c}{**Edge Angle**} & \multirow{2}{*}{**Average**} & \multicolumn{2}{c}{**Hardness H**} & \multicolumn{6}{c}{**Chemical Composition by Mass (\%)**} \\ \cline{3-14}  & \(\Theta\), Degree & & **Wear Off I, g** & **HV** & **HRC** & **Fe** & **C** & **Ni** & **Mn** & **Cu** & **V** & **Mo** & **Cr** & **Si** \\ \hline Original & 24.6 & 3.71 & 515 \(\pm\) 14 & 51 & 97.07 & 0.35 & 0.017 & 1.00 & 0.010 & 0.17 & 0.003 & 1.03 & 0.26 \\ Alt. 1 & 24.0 & 4.18 & 394 \(\pm\) 12 & 41 & 97.46 & 0.23 & 0.030 & 0.89 & 0.009 & 0.12 & 0.003 & 1.00 & 0.22 \\ Alt. 2 & 20.9 & 3.28 & 568 \(\pm\) 11 & 53 & 97.17 & 0.42 & 0.030 & 0.89 & 0.017 & 0.13 & 0.003 & 0.98 & 0.24 \\ Alt. 3 & 27.1 & 3.88 & 469 \(\pm\) 11 & 47 & 96.80 & 0.30 & 0.122 & 0.97 & 0.139 & 0.17 & 0.031 & 1.03 & 0.22 \\ Alt. 4 & 25.4 & 3.54 & 540 \(\pm\) 12 & 52 & 96.97 & 0.35 & 0.047 & 0.97 & 0.039 & 0.13 & 0.0166 & 0.93 & 0.34 \\ Alt. 5 & 29.2 & 4.77 & 349 \(\pm\) 9 & 37 & 97.95 & 0.16 & 0.030 & 0.90 & 0.005 & 0.04 & 0.0030 & 0.49 & 0.24 \\ \hline \hline \end{tabular} 
\begin{tabular}{l c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{2}{c}{**Edge Angle**} & \multirow{2}{*}{**Average**} & \multicolumn{2}{c}{**Hardness H**} & \multicolumn{6}{c}{**Chemical Composition by Mass (\%)**} \\ \cline{3-14}  & \(\Theta\), Degree & & **Wear Off I, g** & **HV** & **HRC** & **Fe** & **C** & **Ni** & **Mn** & **Cu** & **V** & **Mo** & **Cr** & **Si** \\ \hline Original & 24.6 & 3.71 & 515 \(\pm\) 14 & 51 & 97.07 & 0.35 & 0.017 & 1.00 & 0.010 & 0.17 & 0.003 & 1.03 & 0.26 \\ Alt. 1 & 24.0 & 4.18 & 394 \(\pm\) 12 & 41 & 97.46 & 0.23 & 0.030 & 0.89 & 0.009 & 0.12 & 0.003 & 1.00 & 0.22 \\ Alt. 2 & 20.9 & 3.28 & 568 \(\pm\) 11 & 53 & 97.17 & 0.42 & 0.030 & 0.89 & 0.017 & 0.13 & 0.003 & 0.98 & 0.24 \\ Alt. 3 & 27.1 & 3.88 & 469 \(The effects of the hardness HV on the wear I of the blades and of the carbon (C) amount on the chopper blades cutting edge hardness HV are shown in Figure 9.  
The carbon amount (0.16 to 0.42%) in the steel directly influenced the possibility of hardening the cutting edge, suggesting a potential increase in blade life and a reduction in operating costs [17]. The study showed that the current design of the shredder (alignment of the blades along the axis) did not ensure uniform wear intensity and thus simultaneous achievement of the critical conditions. The edge blades of the chopper shaft exhibited the highest wear (4.8-5.0 g, presumably due to the higher straw mass density at the edges of the chopper). The next two blades exhibited lower wear (about 3.0-3.6 g), the next two higher (about 4.0-4.8 g), the next two lower, etc. (Figures 8 and 10). This was a statistically significant difference in attrition. This sinusoidal regularity was likely influenced by the uneven distribution of straw along the length of the chopper shaft as the straw moved through the straw walkers. The systematic differences in wear were caused by the non\(-\)uniform arrangement of the blades along the chopper shaft. This regularity was evident in a randomly selected test of six blades from different manufacturers (designs), although  
Figure 8: Wear of all 80 chopper blades used in the study depending on the position on the shaft: O—original; 1–5—alternatives. Red color indicates wear significantly higher than average, and green significantly lower. Figure 9: The effect of the carbon amount in the steel of the chopper blade on the hardness HV of the cutting edge (**a**) and the effect of the hardness HV on the blade wear I (**b**): O—original; 1,..., 5—alternatives. statistical analysis showed that the average wear of the blades of the different manufacturers was different (Figure 11). The average wear rates of the different manufacturers' shaft grinding blades are shown in Figure 11. The differences were not statistically significant for all average wear rates.