Yiqing Chen

Research on Influence of Abrasive Particles on Lubricating Performance of the Emulsion for Cold Rolling Strip

The tribological performance of different emulsions was tested by MRS-10A four-ball friction and wear testing machine. The JC2000C1 contact angle measurement instrument was used to measure the wetting angle of emulsions. The LEXT OLS4000 laser scanning confocal microscope was applied in analyzing worn spot size of different emulsions. Lubricating properties of the various emulsions were examined on a 4-high cold-rolling mill. The results show that 39.4% significantly reduced the wetting angle of emulsion BG-1 than emulsion BG-2. Friction and wear experiments have demonstrated that the BG-1 emulsion ω were 9.194. The abrasive particles in emulsions have special antiwear and antifriction effects during cold rolling strip steels. The process lubrication experiments results show that abrasive particles affected the stability of emulsion lubricating performance, causing rolling friction coefficient fluctuation. Finally, it changes the rolling technological parameters and cold rolled steel strip surface quality.

Analysis of Stripe Defects on the Cold Rolled Aluminum Strip Surface

In the cold rolling production process, there are always bright, and dark stripe defects on aluminum strips surface when lubricated with rolling oil. The micromorphology and structure of defects were investigated by the surface profiler, OLYMPUS LEXT OLS4000 microscope, and SEM. The constituent elements of the aluminum surface were detected by EDS. The formation mechanism of surface defects was investigated. The analyses of the data suggested that the dark stripe was tougher than the bright stripe surface and the average surface roughness between them varies to 17.8%. The chemical composition of the residue was the significant difference in oxygen content. The oxygen content of dark stripe was much higher than the bright stripe defects. The reason for the difference may be that in rolling speed process, the oil film failed to spread uniformly in the vast areas of deformation zone infinite time which led to the rolling oil film thickness distributes unevenly. The areas of the surface with little rolling oil would suffer insufficient lubrication and cause rougher surface. Moreover, the fresh surface without rolling oil is more likely to be oxidized. The different roughness and composition lead to the difference in macro morphology which is the stripe defects on the surface of aluminum strips.