## 2 Materials and Methods
### FEM Simulations and Experimental Design  
For the optimization of the cutting parameters affecting the turning of the AISI 52100 bearing steel material, the Box-Behnken experimental design, which was used in the lowest number of experiments in the experimental systems created with the RSM, was used. After the experimental design was decided, the cutting parameters affecting the turning of AISI 52100 bearing steel were determined based on the literature review in Table 2, with their levels given in Table 5.  
After the experimental design was determined, the frequencies of the cutting parameters used in the studies in Table 2 were created and are given in Figure 2 to determine the cutting parameters affecting the turning of AISI 52100 bearing steel. According to Figure 2, for the optimization of the cutting parameters used in the processing of AISI 52100 bearing steel, it was observed that the feed rate was used in all 19 studies and cutting speed and depth of cut parameters were used in 18 studies. Due to this result, it was decided to use these cutting parameters in our study, and their levels are given in Table 5. \begin{table}
\begin{tabular}{l l} \hline \hline
**Properties** & \multicolumn{2}{l}{**Workpiece Material (AISI 52100 Steel)**} \\ \hline Young’s modulus (GPa) & 210 \\ Density (kg/m\({}^{3}\)) & 7.83 \\ Poisson’s ratio & 0.3 \\ Specific heat (J/kg \({}^{\circ}\)C) & 476.975 \\ Thermal conductivity coefficient (W/(m \({}^{\circ}\)C)) & 46.6 \\ Thermal expansion (\(\mu\)m/(m \({}^{\circ}\)C)) & 1.19 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The mechanical and thermal properties of the AISI 52100 steel [73]. \begin{table}
\begin{tabular}{l l l l l l l l l} \hline \hline
**Element** & **C** & **Si** & **Mn** & **P** & **S** & **Cr** & **Mo** & **Al** & **Fe** \\ \hline \% & 0.973 & 0.27 & 0.33 & 0.016 & 0.001 & 1.41 & 0.02 & 0.025 & Balance \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The chemical composition of AISI 52100 bearing steel. \begin{table}
\begin{tabular}{l l l l l} \hline \hline  & & & \multicolumn{3}{c}{**Levels**} \\ \cline{3-6}
**Parameters** & **Symbol** & \begin{tabular}{l} **Low** \\ \(-\)**1** \\ \end{tabular} & \
\begin{tabular}{l} **Center** \\ **0** \\ \end{tabular} &
\begin{tabular}{l} **High** \\ **+1** \\ \end{tabular} \\ \hline Cutting Speed (m/min) & \(V\) & 150 & 175 & 200 \\ Depth of cut (mm) & \(d\) & 0.5 & 1 & 1.5 \\ Feed rate (mm/rev) & \(f\) & 0.1 & 0.2 & 0.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The cutting parameters and levels affecting the turning of AISI 52100 bearing steel. According to the Box-Behnken experimental design, the number of experiments to be performed was determined as 15 experiments. In accordance with the experimental design created, the analyses were performed using the finite element method (FEM). The FEM analyses were performed using Third Wave AdvantEdge(tm) (version 7.1) software. This software is FEM software that is optimized for machining operations. Boundary conditions are required to simulate metal cutting operations using the finite element approach. By choosing the best modelling technique and modeling the material, these criteria may be utilized to compute the deformation rate, comprehend how the material of the workpiece will react during plastic deformation, and simulate metal cutting operations. The strain rate and temperature impacts of the structural equations must be identified to describe the dynamic behavior of the model. Changes in metal stress are dependent on the strain, strain rate, and temperature [74; 75; 76]. This study describes the mechanical behavior of the workpiece using the Johnson-Cook (JC) yield-surface-forming material model.