It can be seen from the simulation results that the pouring system of the mud pump body of sand casting in scheme 1 is stepped. During the pouring process of the mud pump body of sand casting, the upper inner sprue is poured in advance, resulting in large scouring of the mold wall by the liquid metal during filling, but a bottom-up temperature gradient distribution is formed in the filling process, Moreover, the temperature drop of the molten metal during the pouring process of the mud pump body in sand casting is small, which provides a better initial temperature condition for the subsequent solidification process, and greatly reduces the possibility of shrinkage and other defects in the mud pump body in the solidification process.
In scheme 2, the bottom pouring system is adopted, the filling process is slow and stable, the metal liquid washes the mold wall less during the filling process, and there is no air entrapment, air entrainment and other phenomena during the filling process. However, the pouring process of sand casting mud pump body lasts a long time, the temperature of metal liquid drops greatly, and the casting surface is easy to oxidize and form a thin film layer during the pouring process of sand casting mud pump body, When the pouring of sand casting mud pump body is completed, the casting mud pump body has partially solidified. The metal liquid of casting mud pump body does not form a good temperature gradient distribution during the pouring of sand casting mud pump body, and it is easy to form shrinkage and other defects in the subsequent solidification process, affecting the final quality of mud pump body.
By comparing and analyzing the advantages and disadvantages of the two process schemes, it can be seen that although the pouring of the mud pump body by sand casting in scheme 2 is stable, it will lead to poor casting quality of the mud pump body, and the bottom injection pouring system should not be used for the mud pump body of steel castings. Although in scheme 1, the sprue filling in each layer is disordered due to unreasonable sprue size design, the whole pouring process of mud pump body in sand casting can still provide a better temperature gradient distribution, and the temperature of molten metal decreases less. Therefore, recalculating the size of each sprue in the gating system to make the pouring process orderly can avoid serious scouring, The casting mud pump body gating system finally adopts process scheme I.