Effects of nano-SiO2 as water-based lubricant additive on surface qualities of strips after hot rolling

Hot rolling experiments were carried out to study the effect of nano-SiO2 on surface qualities including topography, microstructure and oxide scale of rolled strips. Results show that the surface topography becomes smooth with the addition of nanoparticles into base lubricant when the concentration of nano-SiO2 is less than 0.5 wt%. Thickness of oxide scale is decreased from 15 µm to 8 µm and the grain size of microstructure on surface is refined simultaneously. Surface qualities are improved due to the better lubrication performances, which are related to the functions of micro-rolling, polishing and self-repairing of nano-SiO2 on strip surface.