Shell hardening agent

Abstract

The invention relates to a shell hardening agent. The shell hardening agent comprises the following components in parts by weight: 40-90 parts of crystalline magnesium chloride, 10-60 parts of crystalline aluminum chloride and 0.1-1 part of a nonionic surfactant. The shell hardening agent has the advantages of penetrative hardening capability and higher normal-temperature strength and high-temperature strength, the strength of the shell during the production process is ensured, the shell loss is decreased, the residual strength of the shell is reduced and the problem of difficulty in sand removal is solved, the subsequent process operation is facilitated, the produced finished product yield is increased, the labor intensity of workers is reduced and the simplicity in process and environment friendliness are achieved.

Description

technical field [0001] The invention relates to a hardener, in particular to a hardener for lost-wax investment casting medium shells. Background technique [0002] In lost wax investment casting, shell making is a crucial process in investment casting. The quality of the shell directly affects the dimensional accuracy and surface roughness of the casting, which in turn affects the production efficiency and production cost. In the shell process, the hardener plays a key role in the strength and performance of the shell. As an excellent hardener, it must have two characteristics: first, it has high normal temperature strength and high temperature strength, which is beneficial to reduce the loss of the mold shell; second, it has low residual strength, which can solve the difficulty of sand cleaning. problem, which is conducive to the operation of the subsequent process. [0003] At present, traditional investment casting sodium silicate shells are mostly hardened by ammonium...

AI Technical Summary

Problems solved by technology

[0003] At present, traditional investment casting sodium silicate shells are mostly hardened by ammonium chloride, crystalline magnesium chloride, and crystalline aluminum chloride alone to harden the shell. Among them, ammonium chloride has a smaller viscosity and faster penetration speed. High efficiency, low residual strength, easy shelling, but its disadvantages are also very obvious, first of all, a large amount of ammonia gas will be generated, which is very harmful to people and the environment, and the working conditions are harsh. The force is poor, the shell loss is large, and the content of NaCl and NaO2 in the hardening solution needs to be measured regularly, which leads to cumbersome procedures; the material of crystalline magnesium chloride is cheap, odorless and does not pollute the environment, which can fully improve the working conditions, but it is easy to deliquescence and needs to use plastic Container storage has a certain viscosity, and the high-temperature strength and residual strength are low, which cannot fully meet the requirements of shell hardening; crystalline aluminum chloride has high high-temperature strength, good thermal stability and odorless, and its residual strength It is also relatively high, it is difficult to shell, and at the same time, the viscosity of the hardening liquid is relatively high, and the hardening speed is too slow, resulting in low production efficiency and relatively expensive materials.