Film Bearing Centrifugal Casting Numerical Simulation And Process Optimization

Oil-film bearing is widely used in various machinery, iron and steel industriesdue to its advantages such as good load-carrying capacity, low frictioncoefficient and high precision. Bushings are main radial load-carrying membersof bearings. Their material selections, structural designs and manufacturings arekey factors to determine operational performances and service life of bearings.Bushings are generally obtained by pouring alloy materials with properthickness on steel backs in centrifugal casting. So the optimization ofcentrifugal casting progress and system is very important to improve castingquality and work performances of bushings.To improve casting quality of bearing bushings, this paper firstly took theoil-film bearing bushing as research object and the force analysis of fluidparticle during horizontal centrifugal casting was made with consideration ofthe influence of Coriolis force, and the theoretical models of bushing duringfilling and solidification process were established.Secondly, the centrifugal casting process of alloy layer on oil-film bearingbushing was simulated by ProCAST software, and the gating system wasoptimized in view of the casting defects problems of bushing during thecentrifugal casting. Results show that, the optimized casting model can slowdown the impact of liquid metal as it fills, and it is conducive to achievesequential solidification from outside to inside, and it increases the feedingcapacity of liquid metal. The maximum of its shrinkage rate is reduced about5.5%compared to the original model, and the average value of its shrinkage rateis reduced about8.3%. There are less isolated parts in the late solidificationpositions of the optimized casting model compared to the original model, whichimproves the quality of casting.In addition, this paper focuses on the research of the laws on how differentrotational speeds, pouring temperatures and preheating temperatures affectfilling and solidification behaviors of liquid metal. Results show that, with theincreasing rotational speed the filling rate of liquid metal is accelerated. With increasing pouring temperature and preheating temperature, the solidificationrate is reduced and thermal stress is increased. While pouring temperature is toohigh, the solidification rate is accelerated and thermal stress is reduced. Whilepreheating temperature is too low, the greater thermal stress is increased.Preheating temperature has greater effect on filling and solidification behaviorsof liquid metal than pouring temperature. Furthermore, the optimum processparameters were obtained by comparing the influences of six groups ofprocesses. The optimum pouring temperature is440℃, preheating temperatureis250℃and rotational speed is400r/min.At last, the water-cooling experiments were carried out on the steel back ofoil-film bearing by using different water-cooling technologies, which made inthe optimum process parameters after filling process was finished. And the dataof different water-cooling experiments were respectively obtained. Theoptimum water-cooling process of the bearing was obtained by analyzing theexperimental datas and combining with results of experiments in actualproduction. Results show that, the casting quality of bearing bushing under theoptimum process parameters as well as the optimum water-cooling process,meet the requirements of production, which provided scientific theory basis tocontrol and optimize centrifugal casting process in actual production.