The sand casting gating system of the mud pump body is not only the channel for the metal liquid to flow into the mold cavity in sand casting, but also closely related to the casting quality. It can control the speed and filling time of the metal liquid in the filling process, ensure that the metal liquid can fill the whole mold cavity continuously, orderly and smoothly, and prevent bubbles and slag from entering the mold, It can adjust the temperature distribution of sand mold and casting by controlling the filling sequence of liquid metal, so as to realize the sequential solidification of casting. It should also ensure that the liquid metal fills the mold cavity within a certain time to avoid excessive oxidation of liquid metal, which is very important for the quality of casting. If the sand casting gating system of the mud pump body is not designed properly, it will lead to casting defects such as cold shut, iron beans, slag inclusion, sand holes, pores, shrinkage porosity, shrinkage, deformation and cracks. According to statistics, about 30% of the waste products are caused by the unreasonable design of the sand casting gating system of the mud pump body. With the strict requirements of customers for the quality of sand casting of mud pump body, process designers pay more attention to the design of sand casting gating system of mud pump body. The design of sand casting gating system of mud pump body mainly includes the selection of each component structure type, the calculation of section proportion, the introduction position and the introduction method.
The design principles of sand casting gating system for mud pump body are as follows:
(1) When determining the position, number and direction of ingates, the solidification principle and feeding mode of castings should be considered.
(2) The metal liquid shall be filled within the specified time, and the temperature drop of the metal liquid flowing in the sand casting gating system of the mud pump body shall not be too large.
(3) Have enough filling heads and ensure that the contour of the casting is clear.
(4) It has good skimming effect.
(5) Make the liquid metal fill smoothly, avoid serious turbulence, prevent absorption and involvement of gas and excessive oxidation of liquid metal.
(6) The metal consumed by the sand casting gating system of the mud pump body shall be as small as possible and easy to clean.
(7) When filling the mold with liquid metal, the linear velocity shall not be too high to avoid splashing and scouring the mold and core.
(8) Ensure sufficient liquid level rising speed during liquid metal filling to avoid sand casting defects of mud pump body such as cold shut, wrinkle and scar.
(9) Do not destroy the function of core support and cold iron.
(10) Try to reduce the volume of the mold, with simple shape and easy manufacture.
(11) Ensure the sand casting yield of mud pump body.