Precision casting method of double-layer thin-wall bent pipe casting

Abstract

The invention discloses a precision casting method of a double-layer thin-wall bent pipe casting. Aimed at the shortcomings of the prior art, the method comprises the following steps: preparing a wax rod; pressing a soluble carbonyl core by taking the wax rod as a core rod; pressing an inner pipe wax mould by taking the soluble carbonyl core as a core rod; dissolving the soluble carbonyl core with hydrochloric acid to obtain the inner pipe wax mould; performing sand hanging, dewaxing, roasting of a mould shell and the pouring to obtain an inner pipe casting; performing quality inspection; if the inner pipe casting is qualified according to the inspection, preparing a resin sand core by taking the inner pipe casting as a core rod; preparing an integral resin sand casting mould of an exhaust pipe by taking an aluminum alloy metal sample of the exhaust pipe; and putting the resin sand core in the integral resin sand casting mould and performing preheating and pressure-regulation pouring to obtain the exhaust pipe casting. According to the invention, the problem in formation of a double-layer exhaust pipe is solved, and a reliable technical scheme is provided for the casting production. Meanwhile, the production cost is greatly reduced by using a casting formation method, the manufacturing period is shortened, the product quality is improved, and great economic benefits can be gained.

Description

technical field [0001] The invention belongs to the technical field of precision casting, and relates to a precision casting method, in particular to a precision casting method of double-layer thin-walled elbow castings. Background technique [0002] With the development of high-performance aerospace vehicles, its internal components are also developing in the direction of large size, high precision requirements, thin walls, complex structures, and high metallurgical mechanical properties. Traditionally, it needs to be decomposed into multiple parts according to the shape of the component, and each part of the component is formed by machining a whole piece of metal, and then the component is integrally formed by welding. This method makes the forming process of the component extremely complicated, with long production cycle, low efficiency, serious metal waste, high cost and low reliability. Casting molding is especially suitable for mass production because of its low cost ...

AI Technical Summary

Problems solved by technology

[0003] A double-layer thin-walled elbow aluminum alloy casting for aerospace has a complex shape and a large difference in wall thickness of the same part, reaching 21mm, and the wall thickness of some parts is extremely thin up to 1.5mm. Traditionally, the thin-walled elbow is welded as a whole, resulting in component waste. The efficiency is extremely high, and the reliability is extremely low, so the method of precision casting molding is proposed for molding

However, this component is a double-layer pipe fitting, most of which are non-machinable cavities, and the wall thickness and gap between pipes have strict requirements.

From a technological point of view, firstly, the shape of the casting is complex, the inner pipe wall is thin, defects such as insufficient pouring and looseness are prone to occur during the casting process, and relatively thick parts (such as flanges) are prone to looseness. Therefore, the pouring scheme of the component forming process , combined system, pouring parameters, etc. are directly related to the forming integrity, metallurgical quality, mechanical properties, etc. of the components; secondly, the shape and position tolerances and dimensional accuracy requirements are high, which requires that the mold design and production need to fully consider the exhaust pipe after pouring A variety of line shrinkage and volume shrinkage of the molten metal, and the thin wall makes the filling ability of the exhaust pipe poor. Therefore, the stability of the liquid surface pressurization is strictly controlled, and a reasonable pressurization method is provided to suppress the fluctuation of the liquid level. It makes the molding of thin-walled complex and high-quality components particularly important, and these factors make the molding of this type of exhaust pipe extremely difficult

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