Forming method of exhaust hole of long and thin sand core of casting

Abstract

The invention provides a forming method of an exhaust hole of a long and thin sand core of a casting, and belongs to the casting field. When the to-be-manufactured sand core is of a long and thin or sheet structure, a gunpowder wire is laid in the sand core, and the end of the gunpowder wire extends out of the sand core; after the sand core is manufactured, the sand core is coated with alcohol-based paint; and after the paint is air-dried, the end, stretching out of the sand core, of the gunpowder wire is ignited, so that the whole gunpowder wire arranged in the sand core is burnt, and an exhaust hole used for casting is formed in the sand core. Through the method that the hole structure used for exhausting is formed in the sand core by igniting the gunpowder wire, cast molten metal can beplaced in air, the sand core of the long and thin or sheet structure is not prone to being damaged, air in the sand core can be exhausted, and the problem of formation of air holes is solved.

Description

technical field [0001] The invention relates to a method for forming a vent hole of a sand core, in particular to a method for forming a vent hole of an elongated sand core of a casting, and belongs to the field of casting. Background technique [0002] In the foundry industry, the elongated holes that need to be cast on the casting may be straight or curved, and only the lower sand core can be cast. Often the slender sand core is surrounded by molten metal, and the core will generate a large amount of gas under the action of high-temperature molten metal. If the gas cannot be discharged, it will cause pores inside the casting. At present, there are the following methods for sand core exhaust: 1. Pierce the exhaust hole, which is only suitable for larger sand cores and linear sand cores; 2. Put a nylon exhaust rope inside the core, and the thinnest is 4mm at present, so Sand cores with small diameters or flake sand cores cannot be used; 3. Wax lines are put inside the cores...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problem of venting inside the slender holes on the casting or the thin-striped small-hole sand core during casting, the invention provides a method for forming the vent holes of the casting slender sand core. The gunpowder cord is laid in the center, and by igniting the gunpowder cord, a vent hole is formed inside the sand core, which is used to discharge the gas inside the sand core during pouring. The exhaust of fine sand core overcomes the problem of the formation of casting porosity defects

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