Water‐based Cu nanofluid as lubricant for steel hot rolling: Experimental investigation and molecular dynamics simulation

Abstract The lubrication performance of Cu nanofluid was studied through hot rolling tests and non‐equilibrium molecular dynamics simulation. Results showed that nanofluid with 0.5 wt% Cu nanoparticles possessed the optimal effect in reducing the rolling force, finish rolling thickness and rolled surface roughness. The superior lubrication performance was attributed to the formation of protective tribofilm made of Fe/Cu debris, iron and copper oxides as well as amorphous substances with a thickness of about 24 nm, which avoided the direct contact of steel strip and the roll, thus inhibiting the adhesion wear. Molecular dynamics simulation disclosed that the rolling‐dominated motion pattern of Cu nanoparticles with 74.1% rolling and 25.9% sliding motion contributed to a significant decrease in the friction force. Besides, surface defects including the peaks and valleys were polished and repaired by nanoparticles respectively, thus developing the surface quality of hot rolled products.