Research On The Temperature Field Of Solidification Of Sand Coated Iron Mould Casting And Its Affect On Shrinkage Defects

Sand coated iron mould casting is a new casting method that it covers with a certain thickness layer of resin coated sand and come into being a molten shape in the iron mould interspace.It has the both characteristics of metal mold casting and shell mold casting.The main factors of sand coated iron mould casting is that according to select the appropriate thickness of iron mould and resin coated sand layer depending on the thicknesses,structures and materials of castings,in order to control the cooling velocity of castings,then it can improve the quality of castings and avoid casting defects.Therefore,the study of temperature field during sand coated iron mould casting is significant to control the equality of castings.In the paper,research on the temperature field of nudolar iron stepped casting of sand coated iron mould casting in different thickness of casting,iron mould and resin coated sand layer.Analyse the influence of the three parametrics on cooling velocity of casting.Simulated the temperature field of stepped casting during the solidification processing by ANSYS and MAGMAsoft.Then analyse the influence of the temperature field on Shrinkage defects.Finally,let the results of experiment and simulation applied to the process design of sand coated iron mould casting of differential carrier,then verifier the correctness of the process.The main works and results obtained are as follows:1.Thermodetector and thermocouples were used to test temperature curves of the test points on stepped casting of sand coated iron mould casting during solidification processing.Under the condition of stepped casting in different thicknesses of iron mould and resin coated sand layer.The result shows that the thickness of resin coated sand layer is the major factor to control the cooling velocity of the casting.The cooling velocity of casting declines with the increment of the thickness of resin coated sand layer and casting,but the cooling velocity of casting increases with the increment of the thickness of iron mould.2.Use ANSYS to simulate the temperature field of solidification processing of stepped casting which is producted by sand coated iron mould casting.The temperature curve of each test point obtained from ANSYS simulation is general accord with that obtained from actual measurement.3.The numerical simulation of stepped casting is performed by MAGMAsoft,and the predicting location of Shrinkage defects are accord with ANSYS temperature field simulation results.4.According to the influence of the thickness of casting,iron mould and resin coated sand layer to the casting cooling velocity,optimization design was used for sand coated iron mould casting technology of nudolar iron differential carrier.By using MAGMAsoft to simulate the solidification processing,the result shows the casting has no shrinkage porosity defect which proves the technological design is reasonable.