Study On Filling Process In Aluminum Alloy Full Mold Casting

Full mold casting is widely used in the production of automotive molds,because it has the advantages of good surface quality,high dimensional accuracy and high production efficiency.However,due to the existence of the white mold in the cavity,the metal filling process becomes a complicated heat and mass transfer process and castings are prone to defects such as slag inclusions and pores.It is important for the determination of the full mold casting process and the quality control of the casting that fully understanding the aluminum filling process.ZL101A was taken as the research object to different process parameters on the full mold casting process of aluminum alloy.In this paper,the effect of three casting systems and four process parameters on the filling process of aluminum alloy had been studied by high-speed photography and single factor method.Three casting methods included top gating system,bottom gating system and side gating system.Four process parameters included casting temperature,casting thickness,white film density and vibration frequency.A set of control experiments was carried out using the traditional furan resin sand process,which compared the difference between the full mold casting process and the traditional furan resin sand process.The filling form and speed of aluminum alloy under different process parameters were summarized and the reasons for these phenomena were analyzed.1)In the full mold casting,the influence of process parameters on the filling speed was studied by the single factor method.The test results showed:When the casting speed increased from 705?to 785?,the aluminum alloy filling speed increased firstly and then decreased.When the thickness of the casting increased from 4 mm to 20 mm,the filling speed gradually increased.When the white mold density increased from 12 kg/m~3to 21 kg/m~3,the filling speed gradually reduced.When the vibration frequency increased from 0 Hz to 30 Hz,the filling speed gradually increased.2)In the full mold casting process of top gating system,the effect of pouring temperature,casting thickness,EPS density,and vibration frequency on the liquid-filled shape of aluminum alloy was studied.The results show:EPS density had the biggest influence on the filling shape of aluminum alloy.When the EPS density was reduced from21 kg/m~3 to 12 kg/m~3,the filling distance of the aluminum alloy gradually became shorter in the direction perpendicular to gravity.When the aluminum alloy liquid was in contact with the bottom of the cavity,filling morphology of aluminum alloy liquid was unstable and the EPS pyrolysis products were easily wrapped in the aluminum alloy liquid.3)In the full mold casting process of bottom gating system,the effect of pouring temperature,casting thickness,EPS density,and vibration frequency on the liquid-filled shape of aluminum alloy was studied.The results show:vibration frequency had the biggest influence on the filling shape of aluminum alloy.When the vibration frequency was increased from 0Hz to 30Hz,the filling shape of the aluminum alloy liquid was jagged and the pyrolysis products of the EPS were easily wrapped in the aluminum alloy liquid.4)In the full mold process of the single case gate side gating system,when the aluminum alloy flowed into the cavity,the shape of the aluminum alloy liquid was parabolic.When the aluminum alloy liquid collided with the bottom of the cavity,the filling shape was unstable.Aluminum alloy liquid was easy to be oxidized and the EPS pyrolysis products was easily wrapped in the aluminum alloy liquid.In the full mold process of the double case gate side gating system,aluminum alloy liquid first filled the mold cavity from the upper inner gate and then filled the mold cavity from the lower inner gate.When the upper metal liquid and the lower metal liquid converged,the EPS pyrolysis products was easily wrapped in the aluminum alloy liquid.