JPS5974353A - Aluminium cast member - Google Patents

Abstract

PURPOSE:To prevent exfoliation of a metallized layer by integrally casting an aluminium liner formed through extension work with an aluminium basic member and forming the metallized layer having a slidable surface onto the inner peripheral surface of the liner. CONSTITUTION:An aluminium cast member 1 as cylinder block is formed by integrally casting a cylindrical aluminium liner 3 onto an aluminium basic member 2 as the outer shell of the cylinder block and forming a metallized layer 4 onto the inner peripheral surface of said aluminium liner. Said aluminium liner 3 consists of an extruded pipe or drawn pipe which is formed through extension work, and the oxidized film on the outer peripheral surface is removed by shot blasting before casting, and further a number of cavities are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aluminum casting member used, for example, as a cylinder block of an engine.

Conventionally, a cylinder block made of cast aluminum alloy is covered with a cylinder liner made of graphite dispersion cast aluminum alloy to prevent piston seizure, etc., as disclosed in Japanese Patent Laid-Open No. 56-167.
It is known from Publication No. 829. In addition, when the cylinder block is made of cast aluminum as described above, a sprayed layer of a certain type of metal is formed on the inner peripheral surface of the cylinder block, which is the sliding surface with the piston ring, to improve heat dissipation. There is a way to increase the wear resistance several times without reducing the wear resistance. This method involves cutting the inner circumferential surface of the cylinder block to make it smooth and then thermally spraying the inner surface of the cylinder block.

However, when the cylinder block (!/cylinder liner is made of cast aluminum),
There are cavities inside the outer wall of the cylinder block, and these cavities may be exposed on the inner circumferential surface of the cylinder block by the above-mentioned cutting, so the above-mentioned thermal spray layer will float up on these cavities and this part will be damaged. In the broken state, sufficient adhesion to the inner circumferential surface of the cylinder block could not be obtained, resulting in the problem that the sprayed layer would peel off during engine operation.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an aluminum cast member whose thermal sprayed layer does not peel off even when used as a cylinder block.

In order to achieve the above object, in this invention, an aluminum casting member is made of aluminum (
A base material made of aluminum (including aluminum alloy), a liner made of aluminum (including aluminum alloy) formed by stretching and cast into the base material, and a It is composed of a thermal sprayed layer having a moving surface.

The present invention will be explained in detail below.

In Fig. 1, an aluminum cast member l as a cylinder block is made by casting a cylindrical aluminum liner 3 around an aluminum base material 2 as the outer shell of the cylinder block, and spraying the inner peripheral surface of the aluminum liner 3. Layer 4 is formed and exposed.

The aluminum base material 2 was obtained by sand casting, and Table 1 shows an example of the J engineering S symbol AO2A.
The chemical composition of

The aluminum liner 3 was formed by stretching such as a commercially available extruded pipe or drawn pipe, which is a J Engineering S standard product, and had an outer diameter of 80 m and an inner diameter of 72 fins. In addition, before casting, the oxide film on the outer peripheral surface was removed by Schottbufst processing, and at the same time, a large number of depressions were created. The surface roughness of the inner circumferential surface of this aluminum fin 3 was 10 to 15 μm. Table 2 shows the chemical components of an example of the aluminum liner 3, 95052, which is standardized by J Engineering S.

The second surface sprayed layer 4 is made of piano wire (SWP) and wool puden (M
O) was formed by beam spraying in the following manner, and the layer thickness was 128-199μ.

In wire bomb spraying, MO is continuously sprayed four times on the inner peripheral surface of the aluminum liner 3, and SWP is applied on this Mo spray layer.
Two consecutive wire bomb sprayings and one wire bomb spraying of MO were performed alternately, and a total of 25 rounds were performed, including the above-mentioned four consecutive wire bomb sprayings of MO.

Further, after forming the sprayed layer 4, the surface thereof was subjected to homing processing to form a sliding surface 4a.

In addition, as a comparative example, the inner circumferential surface of the aluminum base material of AC2A was finished by cutting, and a thermal spray layer was directly applied on the inner circumferential surface by wire blast spraying of piano wire and molybum in the same manner as described above. formed.

FIG. 2(a) is a micrograph showing the state of adhesion between the aluminum liner and the sprayed layer in the above example (20
0 times), and the figure (to) is a sketch diagram thereof. In addition, FIG. 3(a) is a micrograph (2
00 times), and Figure (1) is a sketch thereof.

As is clear from these, in the case of the comparative example, the blowhole 6 is exposed on the cut surface 5 of the aluminum base material 2, and the sprayed layer 4 is formed on it, so the sprayed layer 4 is lifted up. The lever part is broken. On the other hand, in the case of the example, since the aluminum liner 3 is a stretched product, there are no cavities, and the sprayed layer 4 is evenly adhered to the inner circumferential surface of the liner, and the thermal sprayed layer 4 is in close contact with the inner peripheral surface of the liner 3, compared to the comparative example. The condition is extremely good. In addition, a plurality of test pieces (diameter 10 fins, thickness 10 cm) of the examples of the present invention and comparative examples were prepared, and adhesive ( The adhesion strength of the thermal sprayed layer 4 was examined by gluing aluminum rods with a diameter of 18 pieces with epoxy V resin) and pulling each rod at a multi-speed of 0.5 m/min on both sides. .4kg/- or less, whereas in the example it was 4.1 to 5.2kf/.
-It was.

In the above embodiment, a case has been described in which the aluminum casting member is a cylinder block, but the invention is not limited to this, and it goes without saying that the aluminum casting member may be configured as a member used for other purposes.

Furthermore, although the above embodiments are sprayed layers of piano wire and molybdenum, the present invention does not necessarily require these sprayed layers.

As detailed above, according to the present invention, an aluminum liner formed by a drawing process that does not produce cavities is cast into an aluminum standing material obtained by casting, and a thermal spray layer is applied to this liner. Since the thermal sprayed layer is formed on the inner peripheral surface of the liner, the thermal sprayed layer will not be lifted up from the liner and become disconnected, and its adhesion will be enhanced, so that peeling of the thermal sprayed layer will not occur.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an aluminum casting member according to an embodiment of the present invention, FIG. ) is a sketch thereof, FIG. 3(a) is a photomicrograph substituted for a drawing showing the state of adhesion between the aluminum base material and the sprayed layer, and FIG. 3(a) is a sketch thereof. 1... Aluminum cast member, 2... Aluminum base material, 3... Aluminum liner, 4... Thermal spray layer, 4a... The sliding surface of the thermal spray layer.

Claims (1)

[Claims] (1) An aluminum base material obtained by casting, an aluminum liner formed by stretching and cast into the base material, and a sliding surface formed on the inner peripheral surface of this liner. An aluminum casting member consisting of a thermal sprayed layer.