Partial cooling method of cold iron in investment casting

Abstract

The invention provides a partial cooling technology of cold iron in investment casting. The partial cooling technology comprises the following steps of: 1, manufacturing a wax model by a general investment casting process; 2, designing the cold iron and a wax block which has the same shape and dimension as the cold iron, according to the shape of the outer surface of a hot spot of a casting, and then manufacturing the cold iron and the wax block, wherein the inner surfaces of the designed cold iron and the wax block are clung to the outer surface of the hot spot of the casting in shape, and the cold iron and the wax block are provided with positioning platforms; 3, fixing the wax block to a part requiring partial chilling on the wax model, and tightly clinging to the surface of the wax model; 4 manufacturing a housing at the surface of the wax model, and exposing part of the positioning platform of the wax block from a model housing; 5, dewaxing the model housing; 6, roasting the model housing at high temperature; 7, fixing the cold ion in an opening of the model housing, and positioning through the positioning platform; and 8, casting after preheating the model housing, wherein the partial chilling effect is realized in the cold iron. By carrying out the steps mentioned above, the heat exchange at the hot spot of the casting can be improved, the chilling effect can be realized, and as a result, the purpose of reducing the defect of dispersed shrinkage of a shrinkage cavity in the casting can be realized.

Description

technical field [0001] The invention relates to the technical field of investment casting, in particular to a local cooling method for investment casting cold iron. Background technique [0002] In the field of casting, for complex castings with hot joints, quality problems such as shrinkage cavities and shrinkage porosity are prone to occur at the hot joints. In sand casting, the local cooling rate of the casting can be increased by placing chilled iron in the sand mold to achieve the effect of controlling the cooling sequence. The application of cold iron in sand casting has been very mature, but for investment casting, it is difficult to place cold iron, and it has not been widely used in actual production. At present, there have been some related researches on the chilled iron process of investment casting, such as: presetting the inner chilled iron of the same material as the casting in the mold shell to achieve the effect of local chilling. The disadvantage of this s...

AI Technical Summary

Problems solved by technology

The disadvantage of this solution is that the chilled iron will eventually become a part of the casting, which will bring impurities, scale, etc. into the casting; in addition, the chilled iron cannot be reused

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