JPH0249183B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a composite member that utilizes the self-lubricating properties of carbon to further improve wear resistance.

(Prior Art) Recently, there have been an increasing number of composite members in which only predetermined portions of a metal base body are partially formed of different metals in order to improve wear resistance. For example, while the base body of the piston in an internal combustion engine is made of aluminum alloy, the piston ring carrier part that holds the top ring that is subjected to large repeated loads is made as shown in Japanese Patent Publication No. 60-25619.
For example, a composite member has been proposed in which a porous nickel metal body is cast around the base body.

Conventionally, to obtain such a composite member, first, in order to obtain the metal porous body, a synthetic resin foam (porous body) is subjected to conductive treatment, and a conductive film is applied to the surface as a pre-plating treatment. After forming, electroplating is performed using a hard and wear-resistant metal such as nickel, followed by oxidation treatment to burn off the synthetic resin foam and conductive film, and finally reduction treatment to By removing the oxide film on the surface of the plated wear-resistant metal, a porous body of the wear-resistant metal is formed. Then, by casting the metal porous body thus formed with a metal constituting the base body, such as an aluminum alloy, the metal porous body and the base body are firmly integrated.

By the way, parts that require wear resistance are usually parts that receive sliding or repeated loads from other members. Therefore, in order to improve this wear resistance, it is more preferable to have not only wear resistance simply by improving hardness, but also self-lubricating properties if possible. . Therefore, in order to satisfy this requirement, in the method for obtaining the above-mentioned composite member, after the synthetic resin foam and the conductive film are burnt off to form the metal porous body (after the above-mentioned step), the metal porous body is It is conceivable to add a step of rubbing and filling carbon into the cavity.

(Problems to be Solved by the Invention) However, in the above method, carbon is rubbed and filled into the cavities of the porous metal body, so not only does the carbon itself have to be specially prepared, but the number of steps increases. I will do it.

Moreover, in the above method, since the cavity of the porous metal body is filled from the outside by rubbing, it is not possible to sufficiently fill the inside of the porous metal body, and the carbon also has self-lubricating properties. It cannot be expected to maintain sufficient wear resistance over a long period of time.

The present invention was made in view of the above circumstances, and its purpose is to maintain sufficient wear resistance over a long period of time due to the self-lubricating properties of carbon, without increasing the number of conventional processes. It is an object of the present invention to provide a method for manufacturing a composite member that can eliminate the inconvenience of having to prepare carbon specifically.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a step of subjecting a molded body made of synthetic resin foam to a conductive treatment to form a conductive film, and a step of forming a conductive film on a molded body made of a synthetic resin foam. A process of plating the conductive film with a wear-resistant metal, and carbonizing the synthetic resin foam by subjecting the metal-plated molded body to a heat reduction treatment in a non-oxidizing atmosphere, thereby producing metal in which carbon is generated. The method of manufacturing a composite member is characterized by comprising a step of forming a porous body and a step of casting the porous metal body with a desired metal.

With the above-mentioned configuration, before the step of casting with a desired metal, the metal-plated molded body is heated and reduced in a non-oxidizing atmosphere to carbonize the synthetic resin foam and generate carbon. , carbon is generated in a uniformly dispersed state deep inside the product without any special process. Therefore, sufficient wear resistance based on the self-lubricating property of carbon can be maintained over a long period of time without increasing the number of conventional steps.

Further, in order to provide carbon for the self-lubricating property, the synthetic resin foam used to obtain the porous metal body is effectively used as it is, so there is no need to specially prepare carbon itself. Therefore, it is possible to eliminate the inconvenience of having to specially prepare carbon.

(Example) Examples of the present invention will be described below based on the attached drawings.

Figures 1 to 5 are diagrams showing the principle of the present invention in the order of its main steps, and these Figures 1 to 5 will be explained in comparison with the process diagram (Steps 11 to 16) in Figure 6. . First, in FIG. 1, reference numeral 1 denotes a synthetic resin foam made of, for example, urethane foam.
b, and the skeleton portion 1a is appropriately fractured by a known blasting process as required, and is formed to have a desired porosity. Then, such synthetic resin foam 1 is molded into an appropriate shape, for example, a ring shape, depending on the shape of the part where wear resistance is required (step 11).

FIG. 2 shows the cross-sectional shape of the skeleton portion 1a of the synthetic resin foam 1 shown in FIG. A conductive film 2 (a thin film containing carbon) is formed (step 12).

Thereafter, a plating layer 3 made of a wear-resistant metal was formed on the conductive film 2 by imparting different polarities between the conductive film 2 and a wear-resistant metal such as nickel. A porous metal body B is formed (step 13).

Furthermore, the one on which the plating layer 3 is formed,
For example, by heating in a reducing atmosphere using H ₂ at a temperature of 600 to 800°C for 1 hour, the synthetic resin foam 1 and the conductive film 2 are carbonized, and this carbonization is obtained on the inner surface of the plating layer 3. The remaining (dispersed) carbon is left (step 14).

If the metal 5 constituting the matrix, such as aluminum alloy (for example, AC8A), is cast into the above-mentioned material in which carbon remains by high-pressure solidification casting method, as shown in FIG. metal 5
As the porous metal body B is cast,
The remaining carbon 4 is dispersed in the metal 5 (step 15). In addition,
When the metal 5 is AC8A, the above-mentioned high-pressure solidification casting may be performed at a temperature of 700° C. and a pressure of 800 Kg/cm ^{2 ,} for example.

Finally, a final product C is obtained by performing a hardening treatment (T6 treatment) that is normally performed on aluminum alloys. In addition, during this hardening treatment, an intermetallic compound (Al-Ni compound) between the metal 5 and the plated metal 3 is formed.
In addition to forming stronger bonds, the Al-Ni compound also has high hardness, which improves wear resistance and
This improves the resistance to settling (Step 16).
For this, after step 15, 1-
After heating and holding for 10 hours, water quenching (solutionization of the base material (metal 5) made of aluminum alloy) and tempering may be sequentially performed.

Here, a test example will be described in which the wear resistance of a carbon-containing product of the present invention was compared with a conventional product that does not contain carbon. First, a nickel porous body was used as the metal porous body B (the porosity was 8 for each).
Carbon content is 1.5% by volume only for the product of this invention.
Aluminum alloy (AC8A) was used as the metal for casting this nickel porous body.
In addition, the casting in step 15 in Figure 6 is performed at 700℃ and 800℃.
Kg/cm ² pressure casting is performed, and the heat treatment (T6 treatment) in step 16 in Figure 6 is 510℃ × 5 hours compaction treatment +
Water quenching and further artificial aging treatment at 180°C for 6 hours + air cooling were performed to produce an Al-Ni compound with a thickness of about 10μ.

The composite members obtained as described above, both the inventive product and the conventional product, had a thickness of 3 mm and a length of 10 mm, and the tip surface had a convex surface with a radius of 3 mm over the entire length (10 mm). It was formed as a test piece. Each test piece (the tip surface thereof) was pressed against a slider disk under the following conditions, and the degree of wear was compared. The material of the slider disk is cast iron (C3.5%
Si2.0% Mn0.7% P0.10% or less S0.10% or less
Cr0.2% (balance Fe), test piece pressing load 1.5Kg, lubrication condition is no lubrication, peripheral speed of slider disk at test piece pressing part 5.17
m/s, test time 20 minutes. As a result of this wear test, the conventional product wore 60μ, but the inventive product wore 60μ.
It was confirmed that the carbon-containing product of the present invention was more excellent in wear resistance, with only 40μ being worn.

Next, with reference to FIGS. 7 to 10, a case will be described in which the product C as a composite member is a piston for an internal combustion engine, and the ring carrier portion for holding the top ring is made to have wear resistance.

FIG. 7 shows a piston 21 as a composite member C obtained by the present invention, which has three ring grooves 22, 23, and 24 on its side peripheral surface in order from the top. Of these three ring grooves 22, 23, 24, the upper two ring grooves 22, 23 are used for the gas ring, and the lowermost ring groove 24 is used for the oil ring. The top ring groove 22 located at the uppermost position is formed using a molded body 25 using a wear-resistant metal porous body, and that part is formed with a structure as shown in FIG. has been done.

Based on the above, a molded body 25 made of a ring-shaped synthetic resin foam 1 is subjected to conductive treatment (step 11) as shown in FIG.
12) After plating treatment (step 13), reduction treatment is performed (step 14). The compact 25 after the reduction treatment is set in a predetermined position in a casting mold S consisting of split molds S1, S2, and S3, and then a desired molten metal 5, such as aluminum or aluminum alloy, is placed in a cavity 26 in the casting mold S. As a result, the molded body 25 is surrounded by the cast metal 5 as the base body 27, and the two bodies 25 and 5 (26) are integrated (step 15).
Then, T6 treatment (intermetallic compound generation treatment) is performed (step 16), and the molded body 25 and the base body 1 (metal 5) are more strongly integrated, and
High hardness intermetallic compounds improve wear resistance and fatigue resistance. By forming the top ring groove 22 by machining the molded body 25 integrated with the base body in this way, a piston 21 as a product C as shown in FIG. 7 is obtained.

Although the embodiments have been described above, the present invention is not limited thereto, and is applicable to cylinder liners, brake discs, pawls of shift forks in gear transmissions, inner surfaces of cylinders in master rings for brakes or clutches, etc. that require wear resistance. It can be similarly applied to various members. Furthermore, the proportion of carbon 4 left in step 14 can be easily adjusted by adjusting the thickness of conductive film 2 in step 12. Of course,
The porosity of the metal porous body B can also be easily adjusted.

(Effects of the Invention) As is clear from the above, the present invention has the following advantages:
Without increasing the number of conventional processes, it is possible to maintain sufficient wear resistance over a long period of time due to the self-lubricating properties of carbon, and it also eliminates the inconvenience of having to prepare special carbon. It can be resolved.

[Brief explanation of drawings]

1 to 5 are diagrams schematically showing the main steps of the present invention. FIG. 6 is a block diagram showing an example of the process of the present invention. FIG. 7 is a partially sectional side view showing an example of a piston as a composite member according to the present invention. 8 to 10 are cross-sectional views showing the manufacturing process of the piston shown in FIG. 7. B: Metal porous body, C: Product (composite member), S:
Split type, 1: synthetic resin foam, 2: conductive film,
3: plating layer, 4: carbon, 5: metal (base),
21: Piston (composite member), 22: Ring groove,
25: Molded body (carbon-dispersed metal porous body), 2
7: Mother body.

Claims (1)

[Scope of Claims] 1. A step of performing conductive treatment on a molded body made of a synthetic resin foam to form a conductive film; A step of plating the conductive film of the molded body with a wear-resistant metal; carbonizing the synthetic resin foam by heating and reducing the metal-plated molded body in a non-oxidizing atmosphere to form a metal porous body in which carbon is generated; and coating the metal porous body with a desired metal. A method for manufacturing a composite member, comprising a casting process.