Oil return channel sand core for casting engine cylinder body

Abstract

The invention discloses an oil return channel sand core for casting an engine cylinder body. The sand core adopts a hot core core-making process, the sand core is made of "treasured chrome sand", namely a mixture which is formed by mixing ceramsite, chromite sand and silica sand according to the proportion, by mass, of 2:2:1; and the upper surface of an upper oil channel ore body adopts the inverse deformation amount of 0-0.5 mm, and the inverse deformation amount is gradually increased in the length direction of an oil channel. According to the oil return channel sand core for casting the engine cylinder body, a high-strength precoated sand is adopted for mixing the treasured chrome sand for the sand core so that the sand core can have higher strength, the thermal expansion rate is greatly reduced, and the high-temperature deformation amount of the oil return channel sand core can be effectively inhibited; through reasonable inverse deformation amount design, the local deformation amount of the sand core are reduced; and a core head combines with the gas optimization, so that the problem that the tail end of the core head is blocked during high-temperature expansion deformation iseffectively solved, the stress distribution state is improved, and the fracture risk is reduced.

Description

technical field [0001] The invention belongs to the technical field of casting, and in particular relates to a sand core of an oil return passage for casting a cylinder block of a diesel engine. Background technique [0002] The 2.0CTI diesel engine cylinder block is a national V product developed by our company. The product weighs 74kg and the foundation wall thickness is 4.5mm. It adopts the green sand gravity casting process, and there are two pieces in one type. The sand core of the oil return passage of this product has a span of 380mm, a minimum thickness of 15mm, and a cross-sectional profile of shape. During the production process, it was found that there is a common deformation phenomenon in the oil return channel of the upper mold. This deformation phenomenon is different from the traditional floating core defect. This deformation trend is towards the lower surface of the casting, resulting in poor wall thickness uniformity, and the maximum wall thickness differe...

AI Technical Summary

Problems solved by technology

During the production process, it was found that there is a common deformation phenomenon in the oil return channel of the upper mold. This deformation phenomenon is different from the traditional floating core defect. This deformation trend is towards the lower surface of the casting, resulting in poor wall thickness uniformity, and the maximum wall thickness difference is up to 6mm, accompanied by about 20% broken core defects, causing serious quality problems

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