Simulation Analysis And Optimization Of Casting Technology For Marine Propeller Blade

This type of marine propeller blade is small and medium-sized castings which has complex surface.The blade main bearing shear alternating load and the stress is complex.Because the quality of the blade has an important influence for safe operation of marine,the process of product design and manufacturing requirements are particularly high.Until recently,the blade has been exposed many problems.The result showed that there are casting defects,such as porosity defects,bubbles and slag.Among them,porosity defects of marine propeller blade has been particularly severe,and it had reached above 85%.If improved the quality by several production test,not only increase the production cycles,but also increased the manufacturing cost of product.This paper through the analysis of numerical simulation software and combining the actual situation of production to forecast the casting defects of blade,which in order to find out the cause of defects,and put forward some reasonable suggestions to reduce defects and the actual production.Firstly,after analyzing the structural characteristics and the work environment about the blade and establishing the model of the casting simulation of blade,the initial casting process was simulated by numerical simulation software MAGMA.By analysis the filling and solidification process of the casting,the casting defects in the process blade casting are predicted.It is found that there is a phenomenon of pouring in the casting process,and the casting defects such shrinkage and porosity exist in the solidification process,that is consistent with the actual situation,which proved the correctness of the simulation parameters such as sand boundary condition and thermal physical parameters,rationalization proposals for improving the casting process are proposed.Using bottom gating process to replace the original gating process.The simulation results showed that the bottom gating process is beneficial to the smooth flow of the alloy liquid during the filling process,and reduces the defects such as shrinkage porosity.Then,aiming at the problem of short riser feeding distance in solidification process,the scheme of adding cold iron is put forward in the root of the blade,Which is beneficial to the sequential solidification,and the riser can be well feeding.In this way,only a small amount of shrinkage porosity.Finally,the orthogonal experiment was used to optimize the casting quality,combined with the numerical simulation and actual production situation,three factors which affect the casting quality are selected,such as pouring temperature,casting speed and shell preheating temperature.Through simulation and data analysis,it is found that the pouring temperature has the greatest influence on the quality of the blade,followed by the pouring speed,and finally the shell preheating temperature.The best casting process parameters were pouring temperature is 1150?,casting speed is 90cm/s.shell preheating temperature is 150?.In this casting process parameters,The blade gets the best surface quality and the whole do not has any defects.Finally,the stress field in the solidification process is simulated and analyzed,and the maximum deformation and deformation of the blade are pointed out.,which provides guidance for the application of reverse deformation in the actual production of blades.