A shell-making process for precision casting mold shells of metal parts

Abstract

The invention discloses a making technology for a metal part precise cast molding shell. The making technology includes the steps that a waxy model of a to-be-produced part is pressed through a mold;compound crystal slurry evenly smears the waxy model, then compound crystal sand is uniformly scattered on the surface, and then air drying is performed; the waxy model is uniformly smeared with mullite slurry, then mullite sand is uniformly scattered on the surface, and then air drying is performed; a preset frequency of mullite slurry is repeated, mullite sand is scattered, air drying is conducted, the content of mullite powder in the mullite slurry for usage is decreased gradually, and the mullite sand for usage becomes rougher; smearing of mullite slurry is conducted for the last time, then mullite sand is not scattered, and air drying is conducted; high-temperature steam is used for melting wax and taking out the wax; high-temperature roasting is conducted on the molding shell so thatresidual wax, water and organic matter in the molding shell can be volatized. By improving the technology, production steps are reduced, production costs are lowered, meanwhile, the yield is decreased, and the bad influences on body health of workers are reduced.

Description

technical field [0001] The invention relates to the field of silica sol precision casting technology, in particular to a shell-making process for precision casting mold shells of metal parts. Background technique [0002] At present, investment casting is to melt the metal at high temperature, and then cast it into the mold shell to be cooled and formed; the mold shell is wrapped by layers of materials, and the innermost layer is called the surface layer. The surface layer of the current mold shell is made of natural zircon ore, but the resource of natural zircon ore is limited and expensive, resulting in high material cost for production. [0003] At present, zirconium ore is generally used as the preferred material for the production of shell surface layer, and the shell made of zirconium ore material contains ZrO 2 , SiO 2 Compounds such as FeO and Cr in molten steel are easily combined in a non-vacuum environment 2 o 3 Such compounds produce chemical reactions, resul...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the pitting defects on the surface of the product, it is necessary to create an oxygen-free environment by sprinkling wax and other combustibles on the cast mold group and carrying out box operation to prevent chemical reactions with the surface material of the shell during the molten steel casting process ; but this needs to increase additional procedures and labor costs, and the sprinkled wax will produce a large amount of air pollutants after burning, which will adversely affect the health of operators

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