RESEARCH OF FLUID FRICTION BEARINGS OF WORKING STANDS 630 OF ROLLING MILL 550

Abstract

Analysis of the operation of fluid friction bearings (FFB) of mills 630 showed that the loss of oil on the cages 630 reaches up to 10 tons per year. The reason for this is the imperfection of the seal design, which in turn does not provide the required mode of lubrication of the FFB and leads to high-intensity wear of the surfaces of the sleeve and bearing liner. Which leads to the failure of the FFB before the deadline for replacement of the sleeve and liner. The aim of the study is to determine the load of FFB by mathematical modeling to determine the energy and power parameters of rolling on the example of channel №14, determine the coefficient of friction, study the wear of the surface of the sleeve and liner FFB and provide recommendations for possible ways to improve FFB seals 630. To determine the energy and power parameters of the rolling profile of the channel profile, mathematical modeling was performed using the software product QForm 9. The QForm program is designed for mathematical modeling, based on the finite element method, technological processes of metal forming by taking into account thermomechanical processes of heating and cooling of metal, including in the process of deformation, as well as the interaction of the deformable workpiece with technological tools and equipment. The greatest rolling forces and, accordingly, the load on the FFB will act in the cage №4 and reach 2.8 MN when the roll is captured. The obtained result indicates that the increase in the load acting on the bearing does not significantly affect the change in the coefficient of friction in it, which is in the range of 0.0027 - 0.00274. The value of the friction coefficient μ will be most affected by the viscosity of the oil η and the value of the radial gap δ. The calculation confirmed the transition to the maximum friction during wear to a radial gap of 4 mm, which was observed during the operation of the FFB. The value of the gap δ = 1.8 mm, at which the replacement of the liner and the bearing sleeve will be obtained after 8.8 years of operation. But operational data show that such a gap is reached in 3 years of operation. The reduction in bearing life is due to inadequate friction, namely non-compliance with the viscosity parameters of the oil and its insufficient amount in the bearing. The reason for this is the leakage of oil due to unreliable sealing and ingress of abrasive and coolant rolls. An improved design of seals using V-shaped cuffs is proposed.