During the solidification process of sand casting, the volume of steel castings will shrink, and shrinkage porosity, shrinkage cavity and other hole defects are easy to appear in the final solidification area of sand casting. Therefore, it is necessary to design the feeding system in the process design of sand casting. Through the reasonable riser and subsidy design, the shrinkage of sand casting in the solidification process can be compensated to prevent the shrinkage cavity and other defects of sand casting. Correctly setting the position of riser is very important for obtaining sound sand castings. Improper setting of riser can not eliminate the defects of sand castings, but also may cause cracks and other defects. For steel castings with shrinkage, the principle of sequential solidification is mostly followed in the design of feeding system, and the riser and subsidy are set at the last solidification of sand castings.
(1) The design principle and calculation method of feeding system for steel castings are briefly described, including the determination of hot spot position, feeding channel, number and position of risers and the calculation method of riser size. The design and calculation of feeding system for mud pump body of sand casting are completed.
(2) This paper expounds the function and calculation method of the chilling system in sand mold casting, compares the difference between the internal cooling iron and the external cooling iron, and finally uses the external cooling iron for chilling the mud pump body of sand mold casting. After calculation, the chilling system design of sand mold casting is completed.
The quench system can change the local cooling rate of sand castings, cooperate with the riser, make the sand castings better realize sequential solidification, improve the feeding efficiency of riser and the process yield of sand castings, eliminate the shrinkage cavity and other defects of sand castings, and prevent the deformation of sand castings during solidification; Accelerating the local cooling of sand castings can refine the matrix structure of sand castings and improve the surface strength and wear resistance of sand castings.