WO2022124644A1

WO2022124644A1 - Cast iron-aluminum binding material having good interfacial bonding strength and heat transfer characteristic and method for manufacturing same

Info

Publication number: WO2022124644A1
Application number: PCT/KR2021/017292
Authority: WO
Inventors: 신제식; 김태형; 이지운; 김동응; 조훈; 정재헌
Original assignee: 한국생산기술연구원
Priority date: 2020-12-11
Filing date: 2021-11-23
Publication date: 2022-06-16
Also published as: KR102487981B1; KR20220083452A

Abstract

Provided are cast iron-aluminum binding material having good interfacial bonding strength and heat transfer characteristic, and a method for manufacturing same. The cast iron-aluminum binding material of the present invention comprises: insert material cast-iron; Fe-Al intermetallic compound layer on the cast-iron; and a metal aluminum layer on the Fe-Al intermetallic compound layer, wherein the cast-iron and metal aluminum layer are connected by one or more soft metal or alloy layers perpendicularly penetrating the Fe-Al intermetallic compound layer.

Description

Cast iron-aluminum bonding material with excellent interfacial bonding strength and heat transfer properties and manufacturing method thereof

The present invention relates to a technology for manufacturing a cast iron-aluminum bonding material, and more particularly, to a cast iron-aluminum bonding material having excellent interfacial bonding strength and heat transfer properties.

Since iron-based materials have excellent mechanical properties, they are the most widely used material for parts in the field of transportation equipment such as automobiles and heavy equipment. However, recently, in order to simultaneously satisfy the needs for weight reduction of parts and improvement of performance and reliability, the demand for ferrous-non-ferrous dissimilar metal parts that apply ferrous materials such as cast iron and non-ferrous materials such as aluminum and copper alloy together in a single part is rapidly increasing. .

Among the manufacturing technologies for ferrous-non-ferrous dissimilar metal parts, the fusion welding process, in which a ferrous material is used as an insert material, is placed inside the mold, and non-ferrous molten metal is injected to produce parts at the same time as bonding, is a forced press-fitting method, diffusion bonding method, friction bonding method, welding, etc. Compared to other dissimilar metal parts joining processes, parts with complex shapes can be directly manufactured into the final shape, and the process is relatively simple and the manufacturing cost is low.

However, among the materials used as iron-based core materials for fusion-joined parts, cast iron, which is a casting material, and has excellent connectivity with complex-shaped cast orthopedic parts, exhibits difficult-to-join properties with aluminum alloy, a representative non-ferrous material, so it can be used as a dissimilar metal part. It is the biggest obstacle to its utilization. The causes of the cast iron-aluminum poor bonding properties include low wettability and bonding reactivity with the aluminum alloy molten metal due to the graphite grains on the surface of cast iron, high brittle reaction products generated in the bonding area, narrow bonding reaction process window, and defects generated at the bonding interface. etc.

Until now, the method mainly used to produce cast iron-aluminum dissimilar metal bonding material parts showing the above-mentioned difficult bonding characteristics by the casting process is a mechanical fastening method in which molten aluminum enters and solidifies in a macro-scale pattern formed on the surface of the cast iron insert. . For this purpose, a cast iron insert having a groove formed on the surface by machining or a cast iron insert manufactured by casting to have a protruding surface is used. However, in the cast iron-aluminum dissimilar metal parts manufactured in this conventional way, since metallurgical bonding (metal bonding) between dissimilar materials does not occur, interfacial bonding strength is low and interfacial heat transfer is reduced, thereby causing quality problems.

[Prior art literature]

[Patent Literature]

(Patent Document 1) Korean Patent Publication No. KR2019-0138021

An object of the present invention is to provide a cast iron-aluminum dissimilar metal bonding material having excellent interfacial bonding strength and interfacial heat transfer characteristics, and a method for manufacturing the same.

In addition, the subject of this invention is not limited to the above-mentioned content. The subject of the present invention will be understood from the overall content of the present specification, and those of ordinary skill in the art to which the present invention pertains will have no difficulty in understanding the additional subject of the present invention.

One aspect of the present invention is

insert material cast iron;

an Fe-Al intermetallic compound layer formed on the cast iron; and

Including; a metal aluminum layer formed on the Fe-Al intermetallic compound layer;

The cast iron and the metal aluminum layer, the Fe-Al intermetallic compound layer, characterized in that connected by at least one soft metal layer or an alloy layer penetrating vertically, it relates to a cast iron-aluminum bonding material manufacturing.

The insert cast iron may be at least one of FC cast iron (flaky graphite cast iron), DCI cast iron (spheroidal graphite cast iron), and CV cast iron (compact cast iron).

It is preferable that the cast iron structure of the surface portion forming the bonding interface in the insert cast iron is FC cast iron (flaky graphite cast iron).

It is preferable that graphite grains are detached from the surface forming the bonding interface in the insert cast iron.

The average desorption depth of the graphite grains is preferably 5 to 500 μm.

It is preferable that micro-scale grooves or protrusions are formed on the surface forming the bonding interface in the insert cast iron by machining.

The soft metal layer may be an Al metal layer.

The soft alloy layer may be an aluminum alloy layer including at least one of Fe, Mn, and Si in Al.

At the junction interface of the cast iron material, an Fe-Mn alloy layer having a higher Mn and Si composition than the surrounding cast iron matrix is formed in a predetermined depth region therein, and the Fe-Mn alloy layer is the soft metal layer or alloy layer It is preferable to be connected to

It is preferable that the average thickness of the bonding reaction layer according to the bonding reaction between the insert cast iron material and Al is 5 to 100 μm.

In addition, another aspect of the present invention,

After providing the insert cast iron, the step of desorbing the graphite on the surface;

The process of forming and filling a Fe-Mn alloy layer having a higher Mn and Si content than the cast iron matrix in the void from which the graphite is desorbed by heat-treating the cast iron from which the graphite is desorbed at a temperature of 600 to 1150° C.;

After the heat-treated cast iron is charged into a mold, the process of bonding cast iron and aluminum by pouring aluminum molten metal; it relates to a cast iron-aluminum bonding material manufacturing method comprising a.

In the present invention having the configuration as described above, the cast iron material and the metal aluminum layer are connected by at least one soft metal or alloy layer penetrating the Fe-Al intermetallic compound layer vertically, so that there are cracks or microcavities inside the bonding reaction layer. It is possible to manufacture dissimilar metal materials without generation of defects such as

Accordingly, the dissimilar metal material of the present invention can reduce interfacial thermal resistance and improve interfacial heat transfer properties, and furthermore, solve various problems caused by the existence of a highly brittle bonding reaction layer in the prior art.

1 is a schematic view showing a bonding cross-section of a cast iron-aluminum bonding material according to an embodiment of the present invention.

Figure 2 is a schematic view showing a process of forming a cross-section of the cast iron-aluminum bonding material according to an embodiment of the present invention is formed.

3 is a microstructure photograph of a cross-section of a junction part of a cast iron-aluminum dissimilar metal bonding material manufactured by a conventional fusion bonding method.

4 is a microstructure photograph of the cross-section of the junction of the cast iron-aluminum dissimilar metal bonding material prepared in the present invention.

5 is a diagram showing the interfacial bonding strength of the inventive material and the comparative material in comparison with each other in the embodiment of the present invention.

6 is a diagram showing the interfacial heat transfer coefficients of the invention material and the comparative material in comparison with each other in the embodiment of the present invention.

Hereinafter, the present invention will be described.

Cast iron-aluminum bonding material of the present invention, insert material cast iron; an Fe-Al intermetallic compound layer formed on the cast iron; and a metallic aluminum layer formed on the Fe-Al intermetallic compound layer, wherein the cast iron and the metallic aluminum layer are at least one soft metal layer or alloy layer penetrating the Fe-Al intermetallic compound layer vertically. connected.

As shown in Figure 1, the structure of the cast iron (insert material)-aluminum (cast material) dissimilar metal bonding material of the present invention is the inside of the fusion bonding reaction layer composed of the thick intermetallic compound (1) in the normal direction of the bonding interface (i.e. , in the vertical direction) and a soft (or high toughness) metal layer or metal alloy layer 4 that connects the cast iron 2 and the aluminum 3 is formed. And at the bonding interface of the cast iron material, a Fe-Mn alloy layer 5 having a higher Mn and Si composition than the surrounding cast iron matrix 2 is formed in a predetermined depth region therein, and the Fe-Mn alloy layer ( 5) is connected to the soft metal layer or alloy layer.

In general, the cast iron-aluminum dissimilar metal bonding material manufactured by the melt bonding process has a narrow bonding reaction process window, so it generally falls under the following two cases, which results in low interfacial bonding strength and poor interfacial heat transfer properties.

First, due to graphite grains and oxides present on the surface of cast iron, wettability with molten aluminum is low and bonding reaction does not occur well, so a large interfacial gap exists between cast iron and aluminum. Since bonding (metal bonding) does not occur, the interfacial bonding strength is low and there is a large interfacial thermal resistance.

Second, as the factors impeding the bonding reaction are removed, in this case, Fe atoms are dissolved into the aluminum molten metal from the cast iron insert, and the Al-Fe-based intermetallic compound with high brittleness is rapidly and thickly formed.

In the second case, although chemical bonding occurred between dissimilar metals, i) a highly brittle intermetallic compound layer formed thickly at the junction interface, ii) graphite grains, which are non-metallic particles with high brittleness, existing between the intermetallic compound layers; iii) Due to microcavities formed at the intermetallic compound-graphite grain and graphite grain-aluminum interface, cracks occur very easily at the bonding interface due to thermal and mechanical shock during the manufacture, processing, or use of dissimilar metal bonding materials, resulting in low interfacial bonding intensity values are displayed. In addition, microcavities formed at the intermetallic compound-graphite grain and graphite grain-aluminum interface and cracks generated by impact all increase the thermal resistance between cast iron-aluminum, and the interfacial heat transfer properties are also greatly reduced.

On the other hand, in the present invention, as described above, graphite grains, which are non-metallic particles that are highly brittle and cause fine cavities, are not present in the fusion bonding reaction layer composed of a highly brittle thick intermetallic compound, but in the normal direction of the bonding interface. A soft (or high-toughness) metal layer or metal alloy layer that penetrates through the metal and connects cast iron and aluminum is formed. In the present invention, the soft metal layer may be Al, and the soft metal alloy layer may be an aluminum alloy layer in which Al contains at least one of Si, Fe, Mn, and the like.

Therefore, the resistance to generation/propagation of cracks due to thermal and mechanical shock is increased by the soft metal layer or metal alloy layer formed in this way, and as a result, the interfacial bonding strength is greatly increased. In addition, as a chemical bond is formed between cast iron-aluminum dissimilar metals without defects such as voids, microcavities, and cracks in the interfacial bonding reaction layer, the interfacial thermal resistance is reduced and the interfacial heat transfer properties are greatly improved. Therefore, if the nucleation reaction of the intermetallic compound on the surface of the cast iron insert material can be prevented or delayed from occurring in an appropriate shape at an appropriate location using the above-described characteristics, the intermetallic compound-metal It can be grown in a (alloy) layer composite structure.

In the present invention, the insert cast iron may be one or more of FC cast iron (flaky graphite cast iron), DCI cast iron (spheroidal graphite cast iron), and CV cast iron (compact cast iron).

In addition, in the present invention, as a method of preventing the nucleation reaction of intermetallic compounds from occurring in an appropriate position in an appropriate shape on the surface of the cast iron insert material, it is preferable to desorb graphite grains. It is also necessary to detach the graphite grains from the surface of the cast iron insert in order to improve the wettability with the aluminum molten metal and to create a graphite free zone inside the bonding reaction layer. At this time, it is preferable that the average desorption depth of the graphite grains is 5 to 500 μm.

Furthermore, in the present invention, it is preferable that micro-scale grooves or protrusions are formed on the surface forming the bonding interface in the insert cast iron by machining.

Hereinafter, a method for manufacturing a cast iron-aluminum dissimilar metal bonding material having a bonding reaction layer having an intermetallic compound-metal (alloy) layer composite structure will be described in detail.

First, in the present invention, in order to prepare an insert for fusion welding, a cast iron core material 2 suitable for operation characteristics and fusion bonding process is prepared according to the shape of the part, and graphite grains 6 are provided on the surface of the cast iron material exist.

As cast iron materials for inserts, various cast iron materials can be used depending on the characteristics of parts, such as FC cast iron (flaky graphite cast iron), DCI cast iron (spheroidal graphite cast iron), and CV cast iron (compact cast iron). It is preferable that the graphite grain structure of the surface part to be formed is flake graphite. Flake graphite grains have superior heat transfer performance compared to other graphite-type cast irons such as spheroidal graphite grains, and the graphite grain desorption process before casting bonding and the heat treatment process for healing the cavities 7 from which the graphite grains are desorbed are easy This is because the metal or metal alloy that penetrates the inside of the fusion bonding layer in the normal direction of the bonding interface and connects cast iron and aluminum is formed in a flake shape (= layered). In the case of a highly brittle material, the flake form is vulnerable to thermal and mechanical shock, but in the case of a soft (or high toughness) material, the flake form is an effective form for absorbing and alleviating thermal and mechanical shock. In order to flake the surface graphite grain structure of DCI cast iron or CV cast iron, a specific method is not limited, but an example thereof may include a method of applying a spheroidizing treatment inhibitory element to the mold wall surface during casting.

The cast iron insert prepared as described above improves the wettability with the aluminum molten metal during the fusion bonding process, makes a graphite free zone inside the bonding reaction layer, and melts the inside of the fusion bonding layer composed of an Al-Fe-based intermetallic compound. For the formation of a metal (alloy) layer that penetrates and connects cast iron and aluminum, it is preferable to desorb (7) the graphite grains on the surface of the cast iron material in contact with the molten aluminum.

At this time, it is preferable that the average desorption depth of the graphite grains from the surface is 5 to 500 μm. If the average desorption depth of graphite grains is 5㎛ or less, it is difficult to ensure that all graphite grains are desorbed on the entire bonding interface. Insert material pretreatment effect including simultaneous desorption may not be obtained. On the other hand, if the average desorption depth of graphite grains is 500 μm or more, the thermal conductivity of cast iron is lowered, and surface defects generated during desorption treatment are excessive, which may decrease bonding reactivity.

The present invention is not limited to a specific method for desorbing the graphite grains, and various dry or wet methods may be used without limitation.

The cast iron insert treated with graphite grain desorption as described above subsequently diffuses Fe, Mn, etc. from the surrounding cast iron base to the site where the graphite grains are desorbed, so that the void part disappears and a soft Fe-Mn alloy layer 5 is formed. It is desirable to heat-treat at a high temperature to make it possible. That is, as in FIG. 2, the flake graphite grains 6 present on the surface of the cast iron material for insert are desorbed, and the site 7 where the graphite grains are desorbed diffuses Fe, Mn, etc. from the surrounding cast iron base to the cavity ( Healing so that there is no void) wealth. This is because, if a large number of cavities exist at the bonding interface of the dissimilar metal bonding material, the interfacial bonding strength is lowered and the interfacial thermal resistance is increased, thereby greatly reducing the interfacial heat transfer properties.

The heat treatment is preferably performed at a temperature of 600 to 1150 °C. If the heat treatment temperature is 600 ° C or less, there is a problem in that the cavity healing process time achieved by the atomic diffusion process is excessively long. It can cause problems. The atmosphere for performing the heat treatment is preferably a reducing atmosphere. This is because it is possible to improve the wettability and bonding reactivity with the aluminum molten metal by removing the oxides in the matrix.

In addition, various pretreatments such as sanding treatment may be performed on the surface of the cast iron insert if necessary to improve bonding properties.

In addition, in preparing the cast iron insert for the fusion bonding process, in order to further improve the interfacial bonding strength by the mechanical bonding effect and to further enhance the reliability of the dissimilar metal bonding material, a cast iron material with macro-scale grooves or protrusions formed on the surface The insert may be used to perform a pretreatment process including the above-described graphite grain desorption treatment and high temperature heat treatment for healing the cavity due to graphite grain desorption.

Next, in the present invention, when the molten aluminum alloy 8 is injected after the cast iron insert 2 prepared as described above is mounted in the mold, the Al-Fe-based intermetallic compound (1), which is a cast iron-aluminum fusion junction reactant, is converted into a cast iron material. Graphite grains on the surface are first selectively nucleated in parts that were not desorbed, and then are realized by consuming surrounding Fe atoms and growing.

Specifically, in the cast iron-aluminum fusion bonding process, the surface portion of the cast iron insert 2 is dissolved (Dissolution), so that the Fe solute concentration increases in the aluminum molten metal portion 9 in contact with the cast iron insert. As the Fe composition increases, the degree of supercooling of the molten aluminum increases (compositional subcooling). When the degree of subcooling reaches a certain value or more, the core of the Al-Fe-based intermetallic compound (1) on the surface of the cast iron insert is created However, since the Al-Fe-based intermetallic compound is generated by the crystallization reaction of the intermetallic or hypereutectic system, sub-segregation in which the Fe composition in the molten aluminum around the generated intermetallic compound decreases (segregation in which the solute concentration is lower than the initial concentration) ) is characteristic. As a result, as a gradient of Fe solute concentration occurs, the Fe solutes diffuse from the high concentration region 10 where nucleation does not occur to the low concentration region 11 where nucleation occurs, and this causes the The degree of subcooling is reduced so that the conditions for nucleation cannot be reached. In addition, since the Fe solute is consumed while the intermetallic compound continues to grow, the diffusion movement of the Fe solute from the high concentration region where nucleation did not occur will continue for a while, and eventually the area in front of the surface of the cast iron where nucleation does not occur. As time passes and cooling occurs, the aluminum molten metal 12 in which Fe solute is depleted remains. In this situation, when the temperature is further lowered and the solidification reaction occurs, the Fe solute-depleted part is solidified into an aluminum alloy containing Si, Fe, Mn, etc. dissolved from aluminum or cast iron, and the inside of the intermetallic compound layer 1 is moved in the normal direction of the junction interface. A penetrating soft (or high toughness) metal (alloy) layer 4 is formed.

When the cast iron-aluminum dissimilar metal bonding material is manufactured by the melt bonding process using the cast iron insert prepared by the pretreatment as described above, the average thickness of the bonding reaction layer is preferably 5 to 100 μm. If the average thickness of the bonding reaction layer is 5 μm or less, it is difficult to ensure that the bonding reaction layer is formed over the entire bonding interface. On the other hand, if the average thickness of the bonding reaction layer is 100 μm or more, the intermetallic compound-metal (alloy) layer composite It is difficult to maintain the structure, and cracks easily occur inside the brittle intermetallic compound. Also, in the cast iron matrix adjacent to the junction interface, the Fe atom solid solution into the molten metal is excessive, and Kirkendall pores are formed, which lowers the interfacial bonding force. because it becomes

Hereinafter, the present invention will be described in detail through examples.

(Example)

* After preparing flake graphite cast iron as an insert material, the surface of the insert is sanded to remove oxides or foreign substances, mounted on the mold, and molten aluminum alloy with sufficient superheat is poured and melted to produce a cast iron-aluminum joint, a comparative material. did As a result, the fusion bonding reaction took place to form an Al-Fe-based intermetallic compound layer with a thickness of 30-50 μm at the cast iron-aluminum bonding interface, and graphite grains were present inside the bonding reaction layer. In addition, cracks formed inside the intermetallic compound layer and microcavities formed at the intermetallic compound-graphite grain and graphite grain-aluminum interface could be observed. 3 is a microstructure photograph of a cross-section of a junction part of a cast iron-aluminum dissimilar metal bonding material, which is a comparative material manufactured by a conventional melt bonding method.

For comparison, after preparing flake graphite cast iron as an insert material, graphite grains existing at a depth of 150 to 200 μm from the insert surface were removed by a dry method. Subsequently, high-temperature heat treatment in a reducing atmosphere to diffuse Fe, Mn, etc. to heal the cavities created by the desorption of graphite grains was additionally performed at 1100° C., and then sanded the insert surface to remove oxides or foreign substances, Then, an aluminum alloy molten metal having a sufficient degree of superheat was poured and fusion-bonded to prepare a cast iron-aluminum bonding material, which is an invention material. As a result, the fusion bonding reaction took place and an Al-Fe-based intermetallic compound layer with a thickness of about 50 μm was uniformly formed at the cast iron-aluminum junction interface. It can be seen that the inside of the bonding reaction layer is a graphite-free region in which graphite grains do not exist. In addition, a soft aluminum or aluminum alloy layer that penetrates the inside of the intermetallic compound layer in the normal direction of the bonding interface and connects cast iron and aluminum was formed. And at the bonding interface of the cast iron material, a Fe-Mn alloy layer having a higher composition of Mn and Si than the surrounding cast iron matrix was formed in a predetermined depth region (that is, a region where graphite grains were desorbed and a void was formed). , this Fe-Mn alloy layer was connected to the soft aluminum or aluminum alloy layer. Also, despite the thick formation of the intermetallic compound, no defects such as cracks or microcavities were observed inside the bonding reaction layer. 4 is a microstructure photograph of the cross-section of the junction of the cast iron-aluminum dissimilar metal bonding material of the present invention.

Meanwhile, in FIG. 5, the interfacial bonding strength of the comparative material and the inventive material prepared by the above method was evaluated and shown by the shearing method.

In the case of the invention material, despite the fact that the intermetallic compound, which is more brittle than the comparative material, was formed thicker, a soft aluminum alloy layer that penetrated the inside of the intermetallic compound layer in the normal direction of the bonding interface and connected cast iron and aluminum was formed, and the bonding reaction There were no graphite grains inside the layer, and the tendency to generate defects such as cracks and microcavities was also low. As a result, the interfacial bonding strength was improved by 90% compared to the comparative material.

6 is a graph showing the evaluation of the interfacial heat transfer coefficient of the comparative material and the invention material prepared by the above method by laser scintillation method.

The interfacial heat transfer coefficient of the inventive material was more than 10 times higher than that of the comparative material. In the case of the comparative material, a large number of defects such as cracks formed inside the highly brittle intermetallic layer, microcavities formed at the intermetallic compound-graphite grain and graphite grain-aluminum interface were generated at the bonding interface, but in the case of the invention material, the inside of the intermetallic compound layer was joined. An aluminum alloy layer that penetrates in the normal direction of the interface and connects cast iron and aluminum was formed. And at the bonding interface of the cast iron material, a Fe-Mn alloy layer having a higher composition of Mn and Si than the surrounding cast iron matrix was formed in a predetermined depth region (that is, a region where graphite grains were desorbed and a void was formed). , this Fe-Mn alloy layer was connected to the soft aluminum or aluminum alloy layer. Therefore, there was no generation of defects such as cracks or microcavities in the bonding reaction layer. As a result, the interfacial thermal resistance decreased and the interfacial heat transfer characteristics were improved.

As described above, in the detailed description of the present invention, preferred embodiments of the present invention have been described, but those of ordinary skill in the art to which the present invention pertains may make various modifications without departing from the scope of the present invention. Of course, this is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims to be described later as well as equivalents thereof.

Claims

insert material cast iron;

an Fe-Al intermetallic compound layer formed on the cast iron; and

Including; a metal aluminum layer formed on the Fe-Al intermetallic compound layer;

The cast iron and the metal aluminum layer, cast iron-aluminum bonding material, characterized in that connected to at least one soft metal layer or alloy layer penetrating the Fe-Al intermetallic compound layer vertically.
The cast iron-aluminum bonding material according to claim 1, wherein the insert cast iron is at least one of FC cast iron (flaky graphite cast iron), DCI cast iron (spheroidal graphite cast iron), and CV cast iron (compact cast iron).
The cast iron-aluminum bonding material according to claim 1, wherein the cast iron structure of the surface portion forming the bonding interface in the insert cast iron is FC cast iron (flaky graphite cast iron).
The cast iron-aluminum bonding material according to claim 1, wherein graphite grains are desorbed from the surface forming the bonding interface in the insert cast iron.
[Claim 5] The cast iron-aluminum bonding material according to claim 4, wherein the graphite grains have an average desorption depth of 5 to 500 μm.
The cast iron-aluminum bonding material according to claim 1, wherein micro-scale grooves or protrusions are formed on the surface forming the bonding interface in the insert cast iron.
The cast iron-aluminum bonding material according to claim 1, wherein the soft metal layer is an Al metal layer.
The cast iron-aluminum bonding material according to claim 1, wherein the soft alloy layer is an aluminum alloy layer in which Al contains at least one of Si, Fe, and Mn. .
According to claim 1, wherein a Fe-Mn alloy layer having a higher composition of Mn and Si than the surrounding cast iron matrix is formed in a predetermined depth region at the bonding interface of the cast iron material, and the Fe-Mn alloy layer is Cast iron-aluminum bonding material, characterized in that it is connected to the soft metal layer or alloy layer.
The cast iron-aluminum bonding material according to claim 1, wherein the average thickness of the bonding reaction layer according to the bonding reaction between the insert cast iron material and Al is 5 to 100 μm.
After providing the insert cast iron, the step of desorbing the graphite on the surface;

The process of forming and filling a soft Fe-Mn alloy layer having higher Mn and Si content than the cast iron matrix in the void from which the graphite is desorbed by heat-treating the cast iron from which the graphite is desorbed at a temperature of 600 to 1150° C.;

A method of manufacturing a cast iron-aluminum bonding material comprising a; after charging the heat-treated cast iron into a mold, and then bonding the cast iron and aluminum by injecting molten aluminum.