Long-hole casting shell making process

Abstract

The invention discloses a long-hole casting shell making process. The process comprises the following steps of using zircon sand as a surface layer and mullite sand as a transition layer, after making a shell by 3-4 layers, inserting battens into apertures, conventionally making the shell, sealing slurry, dewaxing, roasting, and inserting ventilation insertion pipes into holes for later use to wait for pouring. The battens are inserted into long holes after shell making, the long holes can be conveniently formed after roasting, the heat dissipation condition after shell casting is improved, the problem of casting shrinkage porosity defects is solved, the ventilation insertion pipes are inserted into the holes to improve the shell casting strength, ventilation is carried out according to needs, and the heat dissipation effect is further improved. The fire escape phenomenon can be effectively prevented, cleaning is convenient, and production efficiency is high.

Description

technical field [0001] The invention relates to the technical field of investment casting, in particular to a shell-making process for long-hole castings. Background technique [0002] At present, the investment casting production process mainly includes three processes: mold making, shell making and mold shell roasting and pouring. The coating module is formed in the secondary cycle process, and then the mold shell is formed by dewaxing, and the cavity in the shell is the part model. In the production process of castings, shell making is a very important process. After a series of processes such as dipping, sanding, and air drying, castings with deep and long holes are not easy to be stained with paste, sanded, and the mold shell has low strength and high scrap rate. Using mechanical processing method, the cost of casting is relatively high. For products with a slightly larger hole diameter, due to the blockage of the shell material in the hole, it is difficult to dissipat...

AI Technical Summary

Problems solved by technology

In the production process of castings, shell making is a very important process. After a series of processes such as dipping, sanding, and air drying, castings with deep and long holes are not easy to be stained with paste, sanded, and the mold shell has low strength and high scrap rate. Using mechanical processing method, the cost of casting is relatively high. For products with a slightly larger hole diameter, due to the blockage of the shell material in the hole, it is difficult to dissipate heat after pouring, resulting in shrinkage and porosity defects of the casting. The current solutions are: 1. 3 layers in the shell Finally, immerse the shell into the slurry to fill the hole. After the slurry is dry, make the next layer of shell to increase the strength of the shell and prevent the occurrence of fire. However, it is difficult to dry after grouting, so the The shell cycle is long; 2. When making the mold, put the prefabricated ceramic core with certain strength at room temperature and high temperature, small expansion coefficient, and chemical stability at high temperature into the mold, press the wax mold, and then make the shell to make a ceramic core with ceramic core. For the shell of the core, the ceramic core in the inner cavity should be removed after pouring, because the ceramic core is difficult to remove after being roasted, the efficiency is low, and the cost of the ceramic core is high

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