Sand mold casting process by means of retractable core bar

Abstract

The invention relates to the technical field of casting, in particular to a sand mold casting process by means of a retractable core bar. The retractable core bar comprises a steel tube, a steel rod,an upper shell, a lower shell, a lifting pull rod and a sliding pull rod. The sand mold casting process includes the following steps of molding and core making, empty cavity forming, assembling and pouring, and box opening and cleaning. The invention mainly aims to provide the sand mold casting process by means of the retractable core bar. By means of the process, the deformability of a sand corecan be improved, meanwhile the exhausting effect of the sand core is improved, the consumption of sand can be reduced, the production environment is guaranteed, and the cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of casting, and in particular relates to a sand casting process using a stretchable mandrel. Background technique [0002] In the production of sand casting, due to the needs of the casting, the sand core almost always extends into the molten metal, and the molten metal will shrink to a certain extent during the cooling and solidification process. If the yield of the sand core is not good, it is very easy to Defects such as hot cracks, stress, deformation and cold cracks occur, resulting in castings being scrapped. The existing technology usually mixes sawdust and coal powder into the core sand, or embeds foam boards in the sand core. The high temperature during pouring causes these substances to burn and volatilize, and then forms a local cavity in the sand core to improve the quality of the sand core. However, these methods generally have the following defects: (1) sawdust, coal powder or foam boards are ...

AI Technical Summary

Problems solved by technology

[0002] In the production of sand casting, due to the needs of the casting, the sand core almost always extends into the molten metal, and the molten metal will shrink to a certain extent during the cooling and solidification process. If the yield of the sand core is not good, it is very easy to Defects such as hot cracks, stress, deformation and cold cracks occur, resulting in castings being scrapped

The existing technology usually mixes sawdust and coal powder into the core sand, or embeds foam boards in the sand core. The high temperature during pouring causes these substances to burn and volatilize, and then forms a local cavity in the sand core to improve the quality of the sand core. However, these methods generally have the following defects: (1) sawdust, coal powder or foam boards are disposable and cannot be recycled; (2) these substances will produce a lot of gas when burned and volatilized, and the If the gas produced by volatile and combustible substances such as moisture and organic matter originally contained, if it cannot be discharged in time, it will hinder the filling of the molten metal, resulting in defects such as insufficient pouring and cold shut; (3) Sawdust or foam board When burning, it will produce a large odor and deteriorate the production environment

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