Physical Simulation Of Fluid Flow Rule In Filling Process Of Vertical Centrifugal Casting Of Titanium Alloy

Vertical centrifugal casting is the main forming method for the precision casting of titanium alloy,widely applied in the production of large and complex thin-walled titanium alloy castings in fields of military,medical and aerospace.Filling process is an important part of vertical centrifugal casting process.If the process is not properly controlled,it will cause defects such as gas,inclusions,which directly affects the quality of the casting.Therefore,it is of great significance to study the filling rule of titanium alloy in vertical centrifugal casting filling process.In this paper,the fluid front morphologies and filling speed of vertical centrifugal casting under different casting process parameters are studied by physical simulation experiments.The main works are listed as follows.Firstly,physical simulation experimental platform for vertical centrifugal casting filling process was built.According to the similarity principle,the similarity criterion of the vertical centrifugal casting filling process was deduced.Based on this,the physical simulation experimental fluid of titanium alloy was prepared,a multi-type runner experimental mold was designed and and the shooting system of fluid front morphologies in the filling process of vertical centrifugal casting was constructed.Secondly,fluid front morphologies were studied at different rotational speeds,fluid viscosities,pouring speeds and gating systems.The results showed that fluid filled along the side wall of cross gate opposite to the direction of rotation,and an intermediate blank flow region appeared inside cross gate.After the filling has been stabilized,the fluid front exhibited a regular arc shape centered on the rotation axis.The higher the rotational speed and the greater the viscosity,the smaller the filling amount,the narrower the flow width of the liquid flow,and the smaller the cross-sectional area,the larger the blank flow area.The smaller the pouring speed,the earlier the flow front exhibited a regular arc shape.At the gating system with multiple inner runner,the fluid filled layer by layer from outside to inside.Finally,the variation rules of filling speed at different rotational speeds,pouring speeds and gating systems were studied by flow visualization technique of tracer particle.The results showed that the filling speed reduced rapidly at the initial stage,then decreased slowly,and finally kept smooth.The lower the rotational speed and the greater the pouring speed,the greater the filling speed in the filling process.The gating system with multiple gates had the fastest filling speed and the shortest filling time.The physical simulation experiment is applied to provide data support for the process optimization design of titanium alloy vertical centrifugal casting filling process,which makes great significance for the actual production process.