Method for preventing decarburization of surface of constructional steel investment casting

A technology for structural steel and castings, applied in the directions of casting molds, casting mold components, casting molding equipment, etc., can solve the problems of large pollution in the working environment, and the effect of preventing decarburization is not very good, so as to reduce the residual strength and facilitate the decarburization. Shell cleaning, the effect of improving the preventive effect

Inactive Publication Date: 2010-03-03
GUIZHOU ANJI AVIATION PRECISION CASTING
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AI Technical Summary

Problems solved by technology

The method of adding an appropriate amount of carburizing agent to the preheated sand grains of the mold shell to prevent decarburization of the casting surface is relatively polluting to the working environment, because the granular carburizing agent will become powdery after repeated use. And the effect of preventing decarburization is not very good

Method used

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specific Embodiment approach

[0006] Specific embodiments: 1, coating ratio: graphite powder accounts for 5%~6% of whole slurry weight ratio, and the coating density of preparation is 1.7 (g / cm )~2.0 (g / cm ).

[0007] 2. Scope of application: This method is applicable to the third, fourth and fifth layer slurry of ethyl silicate coating or silica sol coating shell.

[0008] 3. Specific operation steps:

[0009] 1) Prepare ordinary ethyl silicate paint or silica sol paint slurry according to the process regulations, and stir evenly;

[0010] 2) weigh the coating slurry weight, calculate the weight that needs to add graphite powder;

[0011] 3) weigh the graphite powder weight;

[0012] 4) Add the weighed graphite powder into the prepared slurry, stir with a fast mixer for 5-8 minutes, and then use the module to coat the slurry and sprinkle sand.

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Abstract

A method for preventing decarburization of the surface of a constructional steel investment casting belongs to the field of preventing decarburization of the surface of a casting. Graphite powder isadded in the shell slurry of the constructional steel investment casting to prevent the decarburization of the surface of the casting; the mixture ratio of the slurry is that the graphite powder accounts for 5-6% of the weight percent of the whole slurry; and the function of adding the graphite powder is as follows: after alloy liquid is poured into the shell, the graphite powder in the shell forms a reductive protective layer under high temperature state so as to effectively prevent the alloy liquid from generating surface oxidation during the solidification process. The method has simple operation and convenient usage, increases the air permeability of the shell, is beneficial to filling when in casting, can properly reduce residual intensity of the shell, and is beneficial to unshelling and cleaning; and the method is suitable for the third layer, the fourth layer and the fifth layer of slurry of the shell of ethyl silicate coating or silica solution coating.

Description

Technical field: [0001] The invention relates to preventing the surface decarburization of castings, in particular to a method for preventing the surface decarburization of structural steel investment castings. Background technique: [0002] Structural steel investment precision castings are widely used in aviation, aerospace, and weapon industries. With the continuous development of casting technology, the requirements for investment precision castings are getting higher and higher. The surface of many castings requires casting without margin, and the decarburization depth of the casting surface must not exceed the specified range. The surface decarburization of investment castings is a relatively serious defect. Decarburization will reduce the carbon content of the surface layer of steel, which is more obvious for medium carbon steel and high carbon steel. In order to prevent this defect, methods such as reducing the preheating temperature of the mold shell, lowering the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22C1/04B22C9/04
Inventor 何健
Owner GUIZHOU ANJI AVIATION PRECISION CASTING
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