# Influence of Cutting Parameters and MQL on Surface Finish and Work Hardening of Inconel 617
## 3 Methods and Materials  
The machining experiments were conducted on a Nakamura-Tome SC-450 CNC lathe (Nakamura-Tome Precision Industry Co. Ltd., Ishikawa, Japan) and used a Kistler Type 9129 AA dynamometer tool holder (Kistler Instrument Corp., Mississauga, ON, Canada) to gather cutting force data at a sampling rate of 10 kHz. The Kistler LabAMP System was used for further data processing. The test workpiece was a round bar of forged, solution-annealed Inconel 617, whose properties are listed in Table 2. The bar had an initial diameter of 127 mm (5\") and length of 254 mm (10\") that was manufactured and tested by Bibus Metals AG (Bibus Metals AG, Fehraltorf, Switzerland) according to the following specifications provided by the supplier, as shown in Table 3. The experimental setup can be seen in Figure 1.  
The tool holder is adapted with a nozzle to provide a flood coolant for the operation to cool the tool and workpiece while also flushing chips away from the contact point and cutting zone. The flood coolant was directed towards the rake face of the tool where chip formation occurs. For near-dry machining, an external MQL nozzle was adapted to the tool fixture to allow for oil mist deposition on the rake face of the tool where the point of highest temperatures occurred. This nozzle was connected to a compressed air line and provided compressed air at a constant 7 bar to aerosolize the MQL oil. Table 4 outlines the details of the coolant and oil used in the flood coolant and MQL tests. A Kennametal (Kennametal Inc., Pittsburgh, PA, USA) K313 grade Kenloc(tm) tungsten carbide finishing insert (ISO catalogue number CNGG120408 FS) was used in the turning tests as the substrate and uncoated tool, with coating depositions performed by commercial manufacturers, as listed in Table 5. The tool insert was held in an ISO catalogue number DCLNL124 BK3 -5\({}^{\circ}\) tool holder. The experiment was conducted using three studies to evaluate different parameters in cutting that affect the surface condition of the Inconel 617 workpiece: tool coatings, cutting parameters, and coolant. Study A was conducted to measure the tool life of the uncoated and coated tools. Coatings were deposited either through physical vapour deposition (PVD) or chemical vapour deposition (CVD). The ISO 3685 standard for tool life testing in single-point turning tools was used to determine the cutting parameters of this test [41]. A low cutting speed of 40 m/min was used with a 0.125 mm/rev feed rate and 0.25 mm depth of cut. Cuts were performed in 50 mm passes over the workpiece until the tool reached 300 \(\upmu\)m of flank wear, which is the failure criterion determined by the referenced \begin{table}
\begin{tabular}{c c c} \hline \hline
**Deposition Mode** & **Coalant/Lubricant** & **Flow Rate** \\ \hline \multirow{2}{*}{Flood} & Castrol Hysol MB 50 & \multirow{2}{*}{0.8 L/min} \\  & (Wakefield Canada Inc., Toronto, ON, Canada) & \\ \hline \multirow{2}{*}{Minimum Quantity Lubrication} & KSL Lubricants Inc. SD 33 MQL 10:1 & \multirow{2}{*}{130 mL/h} \\  & (KSL Lubricants Inc., Burlington, ON, Canada) & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Coolant deposition techniques used in this study. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & & & & & & & & & & & \\ \hline
**Ni** & **Cr** & **Co** & **Mo** & **Al** & **C** & **Fe** & **Mn** & **Si** & **S** & **Ti** \\ \hline
54.73 & 21.94 & 11.75 & 8.61 & 1.06 & 0.06 & 1.12 & 0.04 & 0.06 & \textless{}0.002 & 0.42 \\ \hline \multicolumn{10}{c}{} & (**b**) & & & & & & & & & \\ \hline \multicolumn{10}{c}{Density} & & & & & & & & 8360 kg/m\({}^{3}\) & \\ \hline \multicolumn{10}{c}{Melting point range} & & & & & & & & & 1332–1377 \({}^{\circ}\)C & \\ \hline \multicolumn{10}{c}{Specific heat at room temperature} & & & & & & & & & & \\ \hline \multicolumn{10}{c}{Electrical resistivity at room temperature} & & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: (**a**) Chemical composition of Inconel 617 (wt%). (**b**) Mechanical properties of Inconel 617 [4].