JPS6284882A - Production of aluminum composite material - Google Patents

Abstract

PURPOSE:To increase the joining strength of a composite material by treating a cast iron member with hydrochloric acid solution and by letting the hydrochloric acid solution remain on the surface cavity part of after the graphite elusion, then by joining on the surface of the cast iron member the Al layer via a Al diffusion layer. CONSTITUTION:A degraphite treatment is performed, with applying ultrasonic wave by dipping the joining surface of the cast iron member 10 which is pretreated by degreasing, water cleaning, etc. in a hydrochloric acid solution. A new joining surface 12 is formed with the removal of a graphite 14 and the surface part from the joining surface 16 which is prior to the treatment. In this case, the hydrochloric acid solution in the prescribed quantity remains in the cavity part 18 where the graphite 14 is eluded. In this state, then the diffusion of Al diffusion layer 20 is promoted under the surface of Al layer 22 with the Al coating on the joining surface 12. The casting member 10 and Al layer 22 are joined via the Al diffusion layer 20 and the joining strength is remarkably increased by this method.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for manufacturing an aluminum composite material by joining an aluminum member (a member made of hollow aluminum or a member made of an aluminum alloy) and a cast iron member.

(Prior Art) Aluminum composite materials made by joining aluminum members and cast iron members are used in various fields.

For example, in the rotor of a rotor piston engine, the rotor body is made of aluminum alloy (corresponding to the aluminum member described above), and the rotor body is made of cast iron, which has an apex seal groove in the part where the apex seal groove is located. There is a method in which a rotor is formed by joining two seal groove members (corresponding to the above-mentioned cast iron member) to reduce the weight of the rotor and ensure wear resistance of the apex seal groove.

However, in such aluminum composite materials, the bonding strength between the aluminum member and the cast iron member is generally not sufficient, and especially in the case of the rotor described above, mechanical stress is applied to the bonding cloth between the two members while the rotor rotates. is applied repeatedly and is operated in a high-temperature atmosphere, so thermal stress is applied due to the difference in coefficient of thermal expansion between the two members, so there is a risk that the two members may peel off at the bonded fabric due to long-term operation.

Therefore, when manufacturing the aluminum composite material mentioned above, it is necessary to ensure sufficient bonding strength between the aluminum member and the cast iron member.One method for this purpose is to add an aluminum layer (a layer made of aluminum) on the joint surface of the cast iron member. Alternatively, a method can be considered in which an aluminum alloy layer) is deposited and the aluminum members are joined via the aluminum layer.

In order to carry out such a method, it is necessary to apply an aluminum layer to the joint surfaces of cast iron members as described above, and one method for this purpose is as described in Japanese Patent Publication No. 35-6613. A method is known in which an aluminum layer is deposited on the cast iron surface by pickling the surface of the cast iron with hydrochloric acid, then washing with water, drying, and then immersing the cast iron in an aluminum bath.

This method has the advantage that aluminum is diffused into the cast iron surface, and therefore the aluminum layer deposited on the cast iron surface is firmly joined to the cast iron via the aluminum diffusion layer.

However, with this method, the diffusion of aluminum to the surface of the cast iron is insufficient, and therefore the bonding strength between the aluminum layer and the cast iron is still insufficient.As a result, the aluminum member is bonded onto the aluminum layer. In the end, it is difficult to obtain a sufficient bonding strength between the VJ iron and the aluminum member, for example, a bonding strength that satisfies the requirements for the above-mentioned rotor.

In addition, in the above conventional method, pickling with hydrochloric acid is performed before immersion in an aluminum bath because the graphite contained in the cast iron itself is normally exposed on the surface of cast iron, and if the graphite remains exposed, the aluminum This is because if the graphite is covered with 4, aluminum will not be diffused only in the exposed graphite portion, causing incomplete adhesion of aluminum, so this surface exposed graphite is removed by elution in advance with hydrochloric acid.

(Object of the Invention) In view of the above-mentioned circumstances, the object of the present invention is to provide a method for manufacturing an aluminum composite material formed by joining an aluminum member and a cast iron member, the manufacturing method being capable of joining both members more firmly. Our goal is to provide the following.

(Structure of the Invention) In order to achieve the above object, the jΔ method for manufacturing an aluminum composite material according to the present invention, the joint surfaces of cast iron members are treated with JfH acid d.
After the treatment, a predetermined amount of the above hydrochloric acid solution remains in the pores of the bonding surface where the graphite has eluted, and the above bonding is carried out with the chlorine in this hydrochloric acid solution remaining in the pores. Aluminum is deposited on the surface to form an aluminum layer on the bonding surface, and aluminum is diffused into the surface layer below the bonding surface to make the surface layer an aluminum diffusion layer, and aluminum is deposited on the aluminum layer. It is characterized by joining members.

That is, the method according to the present invention performs a degraphitization treatment in which the joint surfaces of cast iron members are pickled with hydrochloric acid to elute graphite, and then the hydrochloric acid on the joint surfaces is not completely washed away with water or the like.
consciously leaving a predetermined amount of the hydrochloric acid solution that has entered the pores after graphite elution on the joint surface by capillary action;
This residual hydrochloric acid solution, more specifically, the chlorine in this solution, is characterized in that it promotes the diffusion of aluminum into the surface layer of the joining surface of the cast iron members during the subsequent aluminum deposition.

In addition, the aluminum member and aluminum 29 in the above
The aluminum in No. 6711 may be aluminum alone or an aluminum alloy.

(Effects of the Invention) As described above, in the method for producing an aluminum composite material according to the present invention, after degraphitizing the joint surfaces of cast iron members with a hydrochloric acid solution, aluminum corrugation is performed on the joint surfaces to form an aluminum layer on the surfaces. An aluminum expansion layer is formed in the surface layer below the surface, and when the aluminum expansion 1BHi7 is used to firmly join the aluminum cum layer formed on the joining surface-12 to the cast iron member, the degraphitization process is performed. After the treatment, the hydrochloric acid solution used in the treatment that entered the graphite elution pores without being completely washed away was allowed to remain for a predetermined amount of m, and this residual J? Since aluminum is deposited in a state where chlorine in the All solution exists in the graphite elution pores, the diffusion of aluminum to the surface layer of the joining surface of cast iron members is promoted by the residual chlorine, and therefore the joining surface of cast iron members is accelerated. An aluminum diffusion layer in which aluminum is sufficiently diffused is formed on the surface layer of the aluminum layer, and as a result, the cast iron member and the aluminum layer are firmly bonded to each other through this aluminum diffusion layer. Since the aluminum member is joined onto the aluminum layer, it is possible to finally obtain an aluminum composite material in which the aluminum member and the cast iron member are extremely firmly joined.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The embodiment described below is a method for manufacturing an aluminum composite material by joining an aluminum member made of ΔQ, -8i-Cu-M9 aluminum alloy and a cast iron member made of Niresist cast iron (D2).

First, a cast iron member made of Niresist cast iron formed into a predetermined shape is prepared, and the bonding surface of the cast iron member (the bonding surface with the aluminum member) is degraphitized using a hydrochloric acid solution, and then aluminum is applied to the bonding surface. to cover.

Cast iron parts contain graphite, and therefore, there are exposed graphite parts on the joint surfaces of these parts.As mentioned above, this exposed graphite is the cause of incomplete adhesion when applying aluminum. Therefore, the bonding surface is quickly pickled with a hydrochloric acid solution, for example, a 5-40% hydrochloric acid aqueous solution, and the exposed graphite is eluted and removed by the pickling.

Note that during this degraphitization treatment, a certain amount of non-graphite portions on the joint surfaces of the cast iron members are also removed, thereby purifying the joint surfaces.

In this example, as a pretreatment, first alkali W;1 fat with 20% sodium orthosilicate was applied, and then 5~
After rinsing with water for 10 minutes, the bonded surface is immersed in a 25% hydrochloric acid aqueous solution, and ultrasonic waves are applied to immediately pickle the surface to perform degraphitization treatment. Note that the purpose of applying ultrasonic waves is to promote degraphitization.

FIG. 1 is a cross-sectional view of a cast iron member before the FFA lead removal treatment. FIG. 1(a) shows the case of spheroidal graphite, and FIG. 1(b) shows the case of flaky graphite. As shown, graphite 14 is exposed on the joint surface 12 of the cast iron member 10.

The second figure is a cross-sectional view of the cast iron member after degraphitizing treatment, and the two-dot chain line 16 in the figure indicates the position of the joining surface before degraphitizing treatment. As shown in the figure, a new joining surface 12 has been purified by removing a certain amount of the surface portion of the cast iron member 10 by degraphitizing treatment.
Graphite 1 is formed and exposed on this bonding surface 12.
4 is eluted, and exposure of graphite to the surface 12 is prevented.

After the above-mentioned 12 graphite treatment is completed, a predetermined amount of the hydrochloric acid solution that has penetrated into the pores 1B from which the graphite has eluted on the bonding surface 12 remains, and the JMIIIQ solution remains or the chlorine in the hydrochloric acid solution remains. The above bonding surface 1
Step 2: Aluminum deposition.

When the degraphitizing treatment by pickling as shown in L has been completed, hydrochloric acid solution is deposited in the graphite elution pores 18 on the joint surface, especially in the narrow spaces around the residual graphite as shown in FIG. Since the salt M solution in the cavity 18 is not completely washed away, a portion of the salt M solution remains in the cavity 18 to be effectively used when covering the aluminum.

In this example, the above degraphitization treatment l! After JI, the above hole 1
In order to leave a predetermined amount of the hydrochloric acid solution in 8, a short period of water washing for 1 to 5 minutes was performed, and after that, the joint surface was dried at 200 to 500 °C, and then the aluminum alloy < Atb held at 700 to 800 °C Aluminum deposition is performed by immersing the joint surface in a molten metal of -s; alloy) for several seconds to several minutes.

The best drying temperature is <400 to 500° C., the higher the drying temperature, the better, from the viewpoint of quickly performing the moisture ′:4 shots. this? By drying at one temperature, water in the hydrochloric acid solution evaporates, and i? The A cord will remain. Furthermore, due to high temperature drying, a dull yellowish brown or brown oxide film (FeO or FezO3) is generated on the bonding surface of the cast iron parts, so wait for this oxide film to be generated before immediately immersing the cast iron in the molten aluminum alloy. .

The immersion time may be appropriately determined depending on the roughness of the aluminum composite material to be manufactured.

When aluminum is deposited with the chlorine in the hydrochloric acid solution remaining in the graphite elution pores 18 as described above, an aluminum layer is formed on the bonding surface 12 and the bonding surface 1
Aluminum is diffused in the surface layer under 2, and an aluminum diffusion layer (responsive to Fe) is formed in the cough area.

An alloy layer of N1
A that easily reacts with the hydrochloric acid solution (chlorine) remaining in 8 and diffuses 9. C9,3 or A9JzCL3, the diffusion of the aluminum is promoted, and 1q of aluminum diffusion layers in which aluminum is sufficiently diffused are formed, and as a result, the aluminum layer is extremely firmly attached to the cast iron member 10 through this aluminum diffusion layer. It will be joined.

<r d3. As mentioned above, an oxide film is formed on the joint surfaces of cast iron members due to high temperature drying, but this oxide film is caused by the reduction of aluminum at P1 temperature when the joint surfaces are immersed in the molten aluminum alloy. Since the aluminum alloy is reduced by the action (the molten aluminum alloy is at a high temperature of about 700° C. or higher), there is no fear that the oxide film will inhibit aluminum diffusion.

Figure 3 is a cross-sectional view of the Gobo iron member when aluminum is deposited, and 20 in the figure is an aluminum diffusion layer, 22
is the aluminum layer.

After forming an aluminum layer by depositing aluminum on the joining surface of the cast iron member as described above, the aluminum member is joined to the aluminum layer. Since both are made of the same metal, this bonding is extremely strong using fused V or the like.

In this example, A-3i-CLJ-M! An aluminum member made of a J-based aluminum alloy is cast into the aluminum layer and joined.

FIG. 4 is a conceptual cross-sectional view of an aluminum composite material formed by joining a cast iron member and an aluminum member as described above. They are firmly bonded via an aluminum diffusion layer 20 formed on the surface layer and an aluminum layer 22 bonded onto the layer 20.

As explained above, in the method according to the present invention, in manufacturing an aluminum composite material by joining an aluminum member and a cast iron member, first, the joining surface of the VI iron member is degraphitized, and then the aluminum coating is applied. This prevents the possibility of incomplete adhesion of aluminum, and also allows a predetermined amount of the salt MFJ solution used for degraphitizing treatment or chlorine in the solution to remain in the graphite elution pores during aluminum adhesion. Since the chlorine in the hydrochloric acid solution reacts with the aluminum and promotes the diffusion of the aluminum into the VR iron, the aluminum layer is formed on the joint surface of the cast iron part through the aluminum diffusion layer in which aluminum is sufficiently diffused. Since the cast iron member and the aluminum member are bonded very firmly together, and the aluminum member, which is a homogeneous metal, is bonded to this aluminum layer, the cast iron member and the aluminum member are ultimately bonded extremely firmly.

The method according to the present invention may be modified in various ways without departing from the spirit thereof, and is not limited to the embodiments described above.

[Brief explanation of drawings]

Figures 1 (a) and (b) are sectional views of the cast iron member before degraphitization treatment, respectively. Figures 2 (a) and (b) are sectional views of the cast iron member before degraphitization treatment, and Figure 3 ( a> and (b) are respectively cross-sectional views of the cast iron member after being covered with aluminum, and Fig. 4 is a cross-sectional view of the aluminum composite material. 10... Cast iron member 12... Joining surface 14.・Black 5018・
・Graphite elution pores 20 ・Aluminum diffusion layer

Claims (1)

[Claims] A method for manufacturing an aluminum composite material made by joining a cast iron member and an aluminum member, the method comprising: performing a degraphitization treatment on the joining surface of the cast iron member to elute graphite with a hydrochloric acid solution; After the treatment, a predetermined amount of the hydrochloric acid solution is left in the pores on the joint surface of the cast iron member formed by elution of graphite, and chlorine in the remaining hydrochloric acid solution is present in the pores on the joint surface. Aluminum is deposited on the bonding surface of the cast iron member to form an aluminum layer on the bonding surface, and the surface layer below the bonding surface is an aluminum diffusion layer in which aluminum is diffused, and the aluminum member is placed on the aluminum layer. A method for producing an aluminum composite material, characterized in that it is formed by joining.