Shell mold preparation method capable of preventing shrinkage porosity inside deep small hole

Abstract

The invention relates to the technical field of investment casting, in particular to a shell mold preparation method capable of preventing shrinkage porosity inside a deep small hole. The method comprises the following steps that a shell mold is prefabricated, specifically, a wax mold is prepared, the wax mold is internally provided with a through hole, the wax mold is sequentially coated with a layer of slurry and a layer of sand, the layer of slurry and the layer of sand form a layer of a shell, and after the N layers of the shell are manufactured in the same way, a layer of back layer slurry or slurry sealing layer slurry is added; the prefabricated shell mold is provided with the deep small hole; the shell mold is dried, specifically, the shell mold is dried, and the deep small hole isblocked by using a wax block after the deep small hole is completely dried; a layer of slurry and a layer of sand are continuously coated to manufacture the shell mold layer by layer until manufacturing of the shell mold is completed; the shell mold is dewaxed, and the wax block is completely separated from the deep small hole after the wax block is completely melted; and the shell mold is manufactured. According to the method, the wax block is used for blocking the deep small hole, blocking of the deep small hole in the subsequent coating process is avoided, it is guaranteed that the deep small hole is provided with a smooth heat dissipation channel, the shrinkage porosity problem caused by unsmooth heat dissipation is solved, and the wax block can be melted off after shell manufacturingis completed.

Description

technical field [0001] The invention relates to the technical field of investment casting, in particular to a shell mold preparation method for preventing shrinkage porosity inside deep and small holes. Background technique [0002] In the investment casting industry, parts with small deep holes will be blocked after the shell is sanded, and the blocked deep small holes are difficult to dissipate heat after the molten steel is poured. Difficulty in heat dissipation leads to slow solidification and easy shrinkage. [0003] Generally, for small parts (module weight is less than 10kg), the shell making process of most investment casting manufacturers is a layer of slurry plus a layer of sand, and the shell is made of 5 to 7 layers. All areas have the same number of layers. For For parts with deep small holes, the small holes will be blocked after 4 to 5 layers of shell making, resulting in the blocking of the holes and the inability to dissipate heat, resulting in shrinkage an...

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Problems solved by technology

[0003] Generally, for small parts (module weight is less than 10kg), the shell making process of most investment casting manufacturers is a layer of slurry plus a layer of sand, and the shell is made of 5 to 7 layers. All areas have the same number of layers. For For parts with deep small holes, the small holes will be blocked after 4 to 5 layers of shell making, resulting in the blocking of the holes and the inability to dissipate heat, resulting in shrinkage and porosity

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