Shrinkage and looseness resisting casting method of air cylinder cover castings

Abstract

The invention mainly belongs to the technical field of engines, and particularly relates to a shrinkage and looseness resisting casting method of air cylinder cover castings. The shrinkage and looseness resisting casting method includes the following steps that (1), a mold is manufactured; (2) an upper sand mold, a lower sand mold and a sand core are made; (3) coating is applied, and the sand coreis dried; (4) core setting is conducted, and four internal chillers are placed on the corresponding position of the upper sand mold; (5) mold assembling is conducted, and a sand box is tightened; (6)iron liquid is cast; and (7) unpacking, clearing, inspection and warehousing are conducted. The iron liquid is injected into the bottom, a balanced solidification molding process is conducted, the casting solidification temperature field is balanced, a second sand core is a resin sand core made from chromite sand and quartz sand in a mixed mode, and comprises a first chiller and a second chiller,through the structure, the heat absorption and cooling effects of the sand core are greatly improved, the temperature field in the solidification process of the casting is balanced, the purpose of balanced solidification is achieved, the probability of shrinkage and looseness of the castings in zones which are prone to shrinkage and looseness is decreased, according to the process, the position is rare shrunk and loosened after a year of machining, and the overall qualified rate of the castings reaches 95% or above.

Description

technical field [0001] The invention relates to an anti-shrinkage casting method of a cylinder head casting, which is mainly used in the technical field of engines. Background technique [0002] The existing diesel engine cylinder head is made of RuT300, which adopts the process of injecting molten iron at the top. This process of casting cylinder head castings has the following problems: [0003] 1. The duct hole of the casting is severely shrinked and the reject rate is as high as 60%. [0004] 2. Only one of the four catheter holes has shrinkage. [0005] The current production process of the molding process of cylinder head castings, for the convenience of modeling, the design of the gating system is generally top injection or middle injection, which results in high temperature of the molten iron in the middle and upper parts, which is more likely to cause difficulties in hot junction feeding in the middle and upper parts, resulting in shrinkage of castings. Loose def...

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Problems solved by technology

[0003] 1. The duct hole of the casting is severely shrinked, and the reject rate is as high as 60%

[0004] 2. Only one of the four catheter holes shrinks and loosens

[0005] The current production process of the molding process of cylinder head castings, for the convenience of modeling, the design of the gating system is generally top injection or middle injection, which results in high temperature of the molten iron in the middle and upper parts, which is more likely to cause difficulties in hot junction feeding in the middle and upper parts, resulting in shrinkage of castings. loose defect

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