Method for preventing casting boss from shrinkage porosity

Abstract

The invention discloses a method for preventing casting bosses from shrinkage porosity, and the method mainly comprises the steps of pressing a wax mold, making a shell, casting and drilling bosses. After the wax mold is pressed, a cooling component is inserted into the center of each boss of the wax mold, a gap between each boss and each cooling component is sealed by a wax material, the radial dimension of each cooling component is 0.3-0.5mm smaller than the hole diameter of each processed boss, the axial dimension of each cooling component is 3-5mm greater than the thickness of each boss, and when the wax molds are assembled, feeding heads are not adhered to the drilled bosses. The cooling components are inserted into the bosses (bosses to be drilled in the machining process) of the wax mold of the casting, so that progressive solidification can be achieved for the casting in the solidification process, the shrinkage porosity at the bosses can be effectively avoided, and the casting technique is simplified.

Description

technical field [0001] The invention belongs to the technical field of investment casting, and in particular relates to a method for preventing shrinkage and porosity defects of casting bosses. Background technique [0002] With the continuous development of casting technology, the requirements for investment precision casting are getting higher and higher. In recent years, there are more and more large and complex castings, and the difficulty of casting is also increasing, especially large castings with multiple bosses and large differences in wall thickness are common. During the casting process, the bosses of castings are prone to shrinkage. Loose defects, it is difficult to meet the production requirements of existing equipment (alloy smelting equipment) with the traditional investment casting process, and the metallurgical quality is also difficult to meet the acceptance criteria. Feeding risers are added to the parts, but if the feeding risers are placed too much, the...

AI Technical Summary

Problems solved by technology

In recent years, there are more and more large and complex castings, and the difficulty of casting is also increasing, especially large castings with multiple bosses and large differences in wall thickness are common. During the casting process, the bosses of castings are prone to shrinkage. Loose defects, it is difficult to meet the production requirements of existing equipment (alloy smelting equipment) with the traditional investment casting process, and the metallurgical quality is also difficult to meet the acceptance criteria. Feeding risers are added to the parts, but if the feeding risers are placed too much, the heat dissipation of the casting will be slow, and a wide solidification area will be formed at the same time, which will cause shrinkage defects in other parts of the casting

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