Table 4.

Heat transfer boundary conditions in machining.

Cooling Method	$\mathbf{Initial} \mathbf{Temperature} \left(\mathbf{°C}\right)$	Heat Transfer Coefficient (Wm−2 K−1)
Dry cutting [86]	20	10–20
High-pressure coolant (HPC)	20	20 × 103–55 × 103
Minimum Quantity Lubrication (MQL) [100,101]	20	200–3 × 103
Cryogenic machining [95,101]	20	30 × 103–50 × 103