Method for local cooling of investment casting formwork

Abstract

The invention discloses a method for local cooling of an investment casting formwork. The method includes the steps of, firstly, analyzing the structures of castings, obtaining hot joint distributionof the castings, determining the position of the formwork which needs local cooling, manufacturing wax molds according to casting requirements, combining the wax molds into a module, and coating the module to manufacture a shell; after the shell is manufactured, forming the demanded formwork through dewaxing and roasting; then, connecting an external tool for formwork shaping to the exterior of the formwork which needs local cooling, and filling gaps in the junctions with steel shots, wherein the formwork is fixed after the gaps are filled with the steel shots; then, conducting casting on theformwork according to technological requirements to complete local cooling of the formwork. According to the disclosed method, the mold and shell manufacturing processes of investment casting are notchanged; meanwhile, the steel shots can fully achieve shaping so that the feeding effect on larger hot joints can be effectively improved, casting defects of the castings such as shrinkage, looseningand cavity shrinkage at these positions are prevented, the quality of the castings is greatly improved, and the process yield of the castings is greatly increased.

Description

technical field [0001] The invention belongs to the technical field of investment casting, in particular to a method for local quenching of investment casting mold shells. Background technique [0002] For hot spots in castings, in sand casting, risers and cold irons are usually set up reasonably to solve the feeding problem of hot spots in castings, so as to obtain qualified products. In investment casting production, after mold making and shell making are completed, molten metal is poured into the mold shell baked at high temperature, so it is difficult to place cold iron, and a larger riser is often installed at the hot joint. For larger single-piece pouring products, the casting process is generally the riser top injection type. Larger hot joints of the product require a large amount of feeding, and often a large riser is designed to feed it, and the solidification time is long, and the cooling rate is low, resulting in coarse grains in the internal structure of the pos...

AI Technical Summary

Problems solved by technology

Larger hot joints of the product require a large amount of feeding, and often a large riser is designed to feed it, and the solidification time is long, and the cooling rate is low, resulting in coarse grains in the internal structure of the position, and it is also very difficult to pass heat treatment. It is difficult to refine the grain, and it is easy to have internal defects such as shrinkage porosity and shrinkage cavity, and at the same time greatly reduces the yield of the casting process

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