Effect Of Mechanical Vibration On The Solidification And Shrinkage Of Castingof ZL205A Alloy By Metal-mould Low Pressure Casting

In this study, I designed the device of low pressure casting by adding mechanical vibration independently, and the vibration characteristic of the device was tested. The influence of vibration on the temperature field, flow field and formation tendency of shrinkage porosity during low pressure casting is studied by means of numerical simulation. The effect of mechanical vibration on solidification feeding of ZL205 A alloy during the low pressure casting used metal mold was researched.The low pressure and vibration casting device includes four parts: pressure module, vibration module, temperature measurement module and metal mold module. Inertial eccentric vibration motor is the vibration source of the device. The metal module can adjust the size and length of the feeding channel. The natural frequency of the device is 19 Hz by measuring the vibration characteristic.Numerical Simulation of mechanical vibration is applied to the low-pressure casting process of ZL205 A alloy and the results showed that the vibration can reduce the casting temperature gradient, increasing the casting solidification time, changing the casting temperature distribution. Moreover, vibration can change convection field during the solidification process, increasing the velocity of flow field. Further more, vibration will affect the position and the shape of shrinkage porosity of casting, reducing the shrinkage porosity of casting.The influence law of vibration frequency, vibration amplitude, channel/casting modulus ratio and the vibration temperature on the shrinkage porosity of castings were obtained through the statistics of shrinkage cavity volume and the density of casting. It is found that the most significant degree of the influence is the ratio of channel/casting modulus, Vibration amplitude has obvious effects on shrinkages cavity volume, The vibration frequency is greater than the amplitude of the factors of the casting shrinkage porosity. The factors on shrinkage cavity volume were investigated: the larger the Channel/casting modulus ratio and the amplitude, the smaller the shrinkage cavity volume; with the vibration frequency and the start vibration temperature increases, the shrinkage cavity volume decreased first and then increased. The effects of shrinkage porosity is the bigger of the ratio of channel, modulus of casting, vibration amplitude and vibration frequency, the smaller of the shrinkage porosity. Through the orthogonal experiment, the optimal vibration parameters of minimizing the volume of shrinkage cavity are the vibration frequency of 15 Hz, vibration amplitude of 0.8mm, channel/casting modulus ratio of 1.25, the start temperature of 610℃; one other, the optimal vibration parameters of minimizing the shrinkage porosity are the vibration frequency of 25 Hz, vibration amplitude of 0.8mm, channel/casting modulus ratio of 1.25, the start temperature of 650℃.