| Lubrication and cooling are seriously considered in cold rolling process of steel strips due to the severe deformable resistance of steel strips, the demand for high quality of surface of steel strips and significant influence by friction. Emulsion is widely used for lubrication and cooling in the cold rolling process to reduce the rolling force and friction. However, quality of surface of strip steel will be significantly affected since a large amount of iron particles with other impurities could be mixed into the emulsion during the circulation of emulsions, which deteriorate the properties of lubricants as well as the coefficient of friction.This paper focused on analysis of the lubrication conditions in cold rolling process by simulation. The main purpose is to analyze the trajectories of the iron particles with the flow of emulsion and the influences of different densities and sizes of iron particles on coefficient of friction. The results revealed that when the diameter of iron particle is4μm～30μm, there is no significant relationship between the coefficient of friction and the size of the iron particle. However when diameter of the iron particle is50μm～70μm, the coefficient of friction enlarges with the increase of size of the iron particles. When the diameter of particle is15μm, the content of iron particles has no obvious influence on friction coefficient, while coefficient of friction increases with the increase of the content of iron particles when the diameter of particle is70μm. Experiments were carried out by using a friction wear testing machine to verify the simulation results. The results showed that what could basically meet the industrial requirements. Finally, the effect of iron particles on surface defects of the cold rolled strips were analyzed and reasonable control technology were proposed based on the mechanism of formation of defect. |
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