Numerical Simulation Of Solidification For Centrifugal Casting Compound Roll

The outer layer of a centrifugal casting compound roll is formed byhorizontal centrifugal casting and the core part by gravity casting. Shrinkageporosity is found in the middle of finished product. In this thesis, the castingprocess of compound roll was simulated and the parameters of casting wereoptimized by using ProCAST.The centrifugal casting module of ProCAST is developed for verticalcentrifugal casting and cannot be used in horizontal centrifugal castingdirectly. The differences between two centrifugal casting containing fillingcharacteristics, force, flowing filed calculation model and shrinkagecharacteristics of solidification were investigated. A new method was putforward creatively to simulate the filling and solidification of horizontalcentrifugal casting. The method is that no pouring system when building3Dmodel, gate setting as the inner surface of out layer of the roller,perpendicular to the axis of rotation and gravity direction, the shrinkagemodel being shut down. It is showed that the filling and solidification process were in accordance with the actual production. The out layer temperaturedistribution is imported as the initial temperature when the core part gravitycasting process was simulated, so that the two kinds technology linked upthrough the software.The reverse authentication method is put forward for the first time inorder to determine the value of interface heat transfer coefficient which is thekey parameter of the simulation process. It is that the simulation resultsincluding solidification time, different point’s temperature and location andsize of the shrinkage porosity have compared with the actual production.When all of them are consistent, the corresponding interface heat transfercoefficient is determined as the correct value and five interface heat transfercoefficients have been determined by this way.Casting parameters including pouring temperature, pouring speed, thesize and its insulation measures of the riser and the sand thickness wereselected as the optimum objects. Simulation results indicate that the lowerpouring temperature appropriately between1270~1320℃can decrease theshrinkage volume, but the pouring time in60~150s effect on the shrinkage is not obvious. The location of shrinkage in the riser moves up along with theheight increase of the riser so that the work part of upper roll neck can getdense castings. Using an insulating riser and reducing the thickness of thesand at the bottom made the shrinkage moving to riser and the shrinkageposition moving down in the bottom, which conducive to improve the qualityof compound rolls.