Abstract: In order to study the relationship between lubrication in deforming zone and surface quality of strip steel, deforming zone lubrication mechanism in hot-strip rolling is calculated and analyzed; and a special device which can be used in hot rolling process lubrication experiment is developed. The effects of different lubrication condition and the oxide film after rolled, surface roughness, morphology after pickling is studied. The results show that：when rolling speed is greater than 2 m/s，the hot-rolled droplets stay in deforming zone less than 0.07 s，far less than sum of burn time and ignition delay time, so there is not enough time for the mixture to burn, the oil-water mixture go through the deforming zone without burning. It is still the traditional liquid lubrication in deforming zone. The surface roughness reduced forty percent and oxide film thickness of lubrication reduced over fifty percent than those without lubrication. Further research on surface morphology after pickling through the 3D microscope shows that lubrication in deforming zone can reduce the surface defect of steel, make the rolling line clear and improve the surface quality obviously

Key words: Deforming zone, Hot-rolling, Lubrication mechanism, Surface quality