Research on the Wear Suppression of Diamond Grain Enabled by Hexagonal Boron Nitride in Grinding Cast Steel

Diamond grinding wheels have been widely used to remove the residual features of cast parts, such as parting lines and pouring risers. However, diamond grains are prone to chemical wear as a result of their strong interaction with ferrous metals. To mitigate this wear, this study proposes the use of a novel water-based hexagonal boron nitride (hBN) as a minimum quantity lubrication (MQL) during the grinding of cast steel and conducted the grinding experiment and molecular dynamics simulation. The experiment demonstrated that compared to dry grinding, the water-based hBN nanofluid can effectively reduce the maximum temperature of a workpiece at contact zone from 408 K to 335 K and change the serious abrasion wear of diamond grain to slightly micro-broken. The molecular dynamics simulation indicates that the flake of hBN can weaken the catalytic effect of iron on the diamond, prevent the diffusion of carbon atom to cast steel, and suppress the graphitization of diamond grain. Additionally, the flake of hBN improves the contact state between the diamond grain and cast steel and reduces the cutting heat and friction coefficient from about 0.5 to 0.25. Thus, the water-based hBN nanofluid as a new MQL was proven to be suitable for the wear inhibition of diamond grain when grinding cast steel.