Casting and forming method for double-layer-material engine cylinder liner

Abstract

The invention discloses a casting and forming method for a double-layer-material engine cylinder liner. The method of combining double-casting-ladle pouring with traditional centrifugal casting is adopted, quantitative outer layer material, namely a light alloy melt, is firstly poured during the centrifugal casting, and then a particulate reinforced composite melt used by an inner material is poured; and after being solidified, the double-layer-material engine cylinder liner with light alloy melt as a radial outer layer and the particulate reinforced composite as an inner layer is obtained. The prominent advantages of the casting and forming method are that: the outer layer material of the cylinder liner can select high-rigidity light alloy and is combined with the particulate reinforced composite at the inner layer, so that the formed cylinder liner has high strength and high rigidity, and the requirements of heat resistance and wear resistance can be met at the same time; in addition, the thickness of the heat-resistant and wear-resistant inner layer of the cylinder liner can be conveniently adjusted; the surfaces of both the inner layer and the outer layer of the cylinder linerhave excellent processing performances; in addition, the casting and forming method disclosed by the invention is short in process, low in cost and high in efficiency, and the forming manufacture canbe easily realized on the existing production line of centrifugal casting.

Description

Technical field [0001] The invention relates to a centrifugal casting forming method, in particular to a casting forming method of a double-layer material engine cylinder liner manufactured by centrifugal casting. Background technique [0002] Cylinder liner is one of the important parts of the engine, and its mechanics and heat transfer performance have an important influence on the working efficiency, service life and power output of the engine. At present, engine cylinder liners are mainly made of alloy cast iron or alloy steel. With the increasing requirements for light weight, energy saving and environmental protection of automobiles, aluminum alloy engine cylinder blocks are more and more widely used. At the same time, aluminum alloy cylinder liners are also being developed at home and abroad to replace cast iron cylinder liners. The sleeve cannot meet the requirements of engine combustion temperature and wear resistance with piston movement. Therefore, aluminum alloy cyli...

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Problems solved by technology

[0004] Honda made ceramic and carbon fiber prefabricated bodies, and used pressure infiltration to manufacture composite material cylinder liners, which were integrated with the cylinder block to meet the heat dissipation requirements of the engine. However, the pressure infiltration method needs to make prefabricated bodies, and then press Infiltration, the liquid phase flows between the narrow gaps of the preform, which takes a long time, so this method has many processes and a long production cycle

[0005] The laser cladding process is mainly to accumulate a certain thickness of reinforced particle layer on the inner surface of the cylinder liner to increase the wear resistance and heat resistance of the cylinder liner. This method requires lasers and control equipment, which is costly, and the laser is used as a point light source. Particles (especially ceramic particles) take a long time and the production efficiency is low

[0006] Centrifugal casting method produces composite material cylinder liner. The reinforcement particles are segregated on the outer layer of the cylinder liner under the action of centrifugal force, which cannot meet the wear resistance requirements of the inner surface. The outer surface of the cylinder liner needs to be finished and assembled with the cylinder body. After segregation of the reinforcement particles Machinability decreases. In addition, the simple use of composite cylinder liners improves the wear resistance of the cylinder liners, but the toughness decreases more; another existing centrifugal casting technology is a kind of "inner layer" announced by Chinese patent CN101338704A. Particle-reinforced cylinder liner and its manufacturing method", the matrix material of this method is Al-Si alloy, and the reinforcing particles are primary Si and Mg 2 Si mixed particles, the reinforced particles of the reinforced layer are added with Mg when the material is molten, and the primary crystal Si and Mg are spontaneously precipitated from the melt during the solidification process during casting. 2 Si particles, the cylinder liner is manufactured by centrifugal casting, which realizes the metallurgical combination of the reinforced layer and the non-reinforced layer by the casting method

But it still has the following deficiencies: 1. The density of reinforcement particles is required to be smaller than that of the matrix and the reinforcement particles are precipitated by self-generation, which limits the selection of cylinder liner materials; 2. The reinforcement particles are segregated in the inner layer, resulting in the machinability of the inner surface of the cylinder liner. sex decline

[0007] Based on the above reasons, the existing aluminum-based or magnesium-based composite cylinder liners are difficult to be popularized and applied. At present, they are only used in a few high-end engines, and most of the cylinder liners are still made of cast iron.

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