## 3 Results
### Illustrative Example of Model 4208 to Determine Hardenability Curves
to a synergistic effect that utilizes the strengths of the individual methods [23; 51]. Table 9 shows the chemical compositions determined when comparing the 42 CrMo4 steel grade hardness with the DIN EN 10083-3 technical standard [49]. Table 10 shows the predicted maximum (Max) and minimum (Min) hardness values for the restricted hardenability towards the top of the scale (+HH) and restricted hardenability towards the bottom of the scale (+HL) bands of 42 CrMo4 steel grade. The predicted values were determined using the developed model. In addition, the DIN EN 10083-3 provides reference values for the 42 CrMo4 (+H) maximum (Max) and minimum (Min) hardness for comparison. This is visually depicted in Figure 8 for enhanced clarity. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multirow{3}{*}{**42 CrMo4**} & \multicolumn{10}{c}{**Distance in mm from Quenched End**} \\ \cline{2-13}  & & \multicolumn{10}{c}{**Hardness in HRC**} \\ \cline{2-13}  & & **1.5** & **3** & **5** & **7** & **9** & **11** & **13** & **15** & **20** & **25** & **30** & **40** & **50** \\ \hline \multirow{3}{*}{+HH} & Max & 59.37 & 58.97 & 58.19 & 57.48 & 56.99 & 56.70 & 56.35 & 55.84 & 54.23 & 51.95 & 49.67 & 44.65 & 40.49 \\ \cline{2-13}  & Min & 54.84 & 54.20 & 53.20 & 52.24 & 50.45 & 47.29 & 43.66 & 40.66 & 37.15 & 35.87 & 34.68 & 32.41 & 30.58 \\ \hline \multirow{3}{*}{+HL} & Max & 57.67 & 57.14 & 56.23 & 55.45 & 54.92 & 54.58 & 54.15 & 53.53 & 51.61 & 49.16 & 46.78 & 42.31 & 38.69 \\ \cline{2-13}  & Min & 52.88 & 52.32 & 51.34 & 50.00 & 47.41 & 43.67 & 40.11 & 37.24 & 33.35 & 32.34 & 31.82 & 30.36 & 28.31 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: 42 CrMo4 steel grades hardness with restricted hardenability scatter bands (+HH and +HL grades). Figure 8: Restricted hardenability scatter band (RH-Band) for the 42 CrMo4 steel grade. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Chemical Composition (\% Mass)**} & **C** & **Mn** & **Si** & **Cr** & **Ni** & **Mo** & **Cu** \\ \hline \multirow{3}{*}{42 CrMo4} & Max & 0.45 & 0.81 & 0.28 & 1.08 & 0.12 & 0.23 & 0.22 \\ \cline{2-13}  & Min & 0.4 & 0.68 & 0.22 & 0.91 & 0.13 & 0.16 & 0.11 \\ \cline{2-13}  & Max & 0.45 & 0.82 & 0.28 & 1.12 & 0.12 & 0.25 & 0.25 \\ \cline{2-13}  & Min & 0.4 & 0.61 & 0.18 & 0.95 & 0.04 & 0.18 & 0.07 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: 42 CrMo4 steel grade and its chemical composition for calculating H-band. Comparing the predicted values with the standard reference values shows that the predictions of the model are generally within the specified hardness ranges, both for the hardenability and hardenability-limited bands. The close agreement between the predicted values and standard values indicates that the model performs well in estimating the hardenability properties of the 42 CrMo4 steel grade. This information is critical to ensure that the steel meets the specified hardness requirements for various applications and contributes to effective material selection and component design. Since the model is data-based and has been trained on datasets comprising nearly 40 steel grades with chemical composition and Jominy distance information, its application extends to the prediction of hardenability curves for these specific steel grades. However, it is important to note one limitation of the model: it cannot predict results for features beyond the range covered by the training datasets.