JP3248884B2 - Method of bonding iron member and aluminum member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method capable of performing an effective rust prevention treatment on a joint between an iron member and an aluminum member.

[0002]

2. Description of the Related Art As a method for joining an iron member and an aluminum member, for example, the following methods are known.
A copper plating film is formed on a portion to be joined of an iron member, and the portion to be joined is immersed in molten solder and subjected to ultrasonic vibration, whereby a solder film is formed at the portion to be joined, and the iron member is formed by the solder film. And the aluminum member. After a flux is applied to a portion to be joined of the iron member, a zinc-based hot-dip plating process is performed to form a galvanized film, and the iron member and the aluminum member are joined by the galvanized film.

[0003]

However, the joint between the iron member and the aluminum member has a problem that, as a practical problem, it is not possible to perform a sufficient rust prevention treatment. Specifically, white rust was generated in the joint at a salt spray test for 96 hours. In addition, if rust prevention treatment is emphasized, there is a possibility that a sufficient bonding strength may not be obtained.

[0004] It is an object of the present invention to provide a processing method capable of performing a sufficient rust preventive treatment on a joint portion between an iron member and an aluminum member without impairing the joint strength.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a flux is applied to at least a portion to be joined on a surface of an iron member, and then a zinc-based hot-dip plating process is performed. A hot-dip plating process for forming a plating film, and a joining portion of an aluminum member is brought into contact with a galvanizing film of a joining portion of an iron member, and the two members are melted by applying ultrasonic vibration to melt the zinc plating film. The method includes a joining step of joining, and a rust prevention step of performing a chromate treatment on a joint portion of both members, and in the hot-dip plating step, using a zinc-based hot-dip plating having an aluminum content of 0.2 to 1% by weight. This is a method for joining an iron member and an aluminum member.

According to a second aspect of the present invention, in the first aspect of the invention, an electroplating step of forming a galvanized film by applying an electrogalvanizing process to at least a portion to be joined on the surface of the iron member is provided in advance. In the next hot-dip plating step, the galvanized film of at least the portion to be joined of the iron member is
After applying the flux, a zinc-based hot-dip plating process is performed to form a galvanized film.

[0007] Chromate treatment is a treatment in which a metal is immersed in a mixed acid containing chromic acid as a main component, and a film of insoluble chromate (chromate) is formed on the metal surface by a chemical reaction. Color chromate treatment, gloss chromate treatment,
There are black chromate treatment and dark green chromate treatment. Specifically, for example, a mixed acid composed of 5 to 10 g / l of sodium dichromate, 0.3 to 0.7 ml / l of sulfuric acid, 2 to 4 ml / l of nitric acid, and 1 to 2 ml / l of acetic acid is used as the treatment liquid. The temperature is set to 30 to 40 ° C. and the immersion time is set to 5 to 30 seconds.

The chromate treatment is generally applied to a galvanized film obtained by electrogalvanizing, and cannot be applied to a galvanized film obtained by zinc-based hot-dip plating. I have. It is considered that the reason for this is that in the zinc-based hot-dip plating, a good chromate film is not formed because smut is formed on the galvanized film during the pretreatment. Then, it is considered that smut is more likely to be generated as the amount of aluminum and other impurities contained in the zinc-based hot-dip plating increases. In the present invention, since the aluminum content of the zinc-based hot-dip plating used is as small as 0.2 to 1% by weight, the formation of smut is suppressed, and a good chromate film is formed on the galvanized film. That is, according to the present invention, a sufficient rust prevention effect can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIGS. 1 to 5 are longitudinal sectional views showing respective steps of a method for bonding an iron member and an aluminum member according to this embodiment. Hereinafter, the joining processing method of the present embodiment will be described. In addition, as the iron member, SS
400 and A5052 as an aluminum member.

First, the entire surface of the iron member 1 is degreased, immersed in (1 + 1) HCl for 30 seconds, washed with water, immersed in flux for 30 seconds, and dried, and as shown in FIG. Flux 2 was applied.

Next, as shown in FIG. 2, the entire iron member 1 to which the flux 2 has adhered is immersed in a bath of zinc-based hot-dip plating 3 at 450 ° C. for 30 seconds, and as shown in FIG. A galvanized film 31 was formed on the entire surface of Sample No. 1. Here, zinc-based hot-dip plating 3 having an aluminum content of 0.2% by weight, that is, zinc-0.2% aluminum hot-dip plating was used.

Next, as shown in FIG. 4, the aluminum member 4 is coated on the galvanized film 31 at the joint 11 of the iron member 1.
Are brought into contact with each other, ultrasonic vibration is applied to the contacted portions to melt the galvanized film 31,
4 were joined. Reference numeral 5 denotes a joining portion between the two members 1 and 4.

Then, the entire members 1 and 4 are immersed in 10% nitric acid for 30 seconds, washed with water, and then immersed in a bath of a chromate treatment solution 6 at room temperature for 120 seconds as shown in FIG. , Washed with water, 60 ° C 60
Dried for 12 minutes at room temperature. As the chromate treatment liquid 6, chromic anhydride 20 g / l, sulfuric acid 5 g /
l, nitric acid 5 g / l, phosphoric acid 15 g / l, and acetic acid 35 g
/ L of mixed acid was used.

(Embodiment 2) Zinc-based 1% aluminum hot-dip plating was used as the zinc-based hot-dip plating 3, and the other conditions were the same as those in Embodiment 1.

(Comparative Embodiment 1) A zinc-5% aluminum hot-dip plating was used as the zinc-based hot-dip coating 3 in the first embodiment.
A zinc plating film 31 is formed in the same manner as
4 were joined. No subsequent chromate treatment was performed. The thickness of the zinc plating film 31 was 6 μm.

(Comparative Embodiments 2 and 3) As zinc-based hot-dip plating 3, zinc-1% aluminum hot-dip coating,
Zinc-0.2% aluminum hot-dip plating was used, and the others were the same as Comparative Example 1. The zinc plating film 31
Were 15 μm and 11 μm, respectively.

(Comparative Embodiment 4) Instead of a zinc-based hot-dip plating process, an electro-galvanizing process is performed to obtain a galvanized film 31.
Was formed, and the others were the same as Comparative Example 1. The thickness of the zinc plating film 31 was 8 μm.

Comparative Example 5 Zinc-5% aluminum hot-dip plating was used as the zinc-based hot-dip plating 3, and the other conditions were the same as in the first embodiment.

(Comparative Embodiment 6) Instead of a zinc-based hot-dip plating process, an electro-galvanizing process is performed to obtain a galvanized film 31.
Was formed, and the others were the same as in the first embodiment.

(Rust Prevention Effect Test) In order to evaluate the rust prevention effect of the joint 5 of both members 1 and 4 in Embodiments 1 and 2 and Comparative Embodiments 1 to 6, a salt spray test was performed on the joint 5. Table 1 shows the results. The indication in Table 1 is
-: Not measured, x: poor, Δ: good.

[0021]

[Table 1]

The following can be seen from Table 1. (i) In Comparative Examples 1 to 4 in which the chromate treatment was not performed, white rust was generated regardless of the aluminum content in the zinc-based hot-dip plating, and irrespective of the zinc-based hot-dip coating or electrogalvanizing. Even that could not be prevented. (ii) When the comparative embodiment 5 is compared with the embodiments 1 and 2, in the comparative embodiment 5, white rust is generated because the zinc-based hot-dip galvanizing has a high aluminum content despite the chromate treatment. Even that could not be prevented. (iii) Comparative embodiment 6 is a conventionally known rust-proofing treatment of a galvanized film. That is, a chromate treatment known as a rust prevention treatment is generally performed on a galvanized film obtained by an electrogalvanization treatment, and the rust prevention effect by the treatment is not only white rust but also iron rust. Even the generation of rust can be prevented. In Embodiments 1 and 2, a sufficient rust-preventing effect is obtained by the chromate treatment in spite of the fact that the zinc-based hot-dip treatment is used instead of the electrogalvanization treatment. (iv) From the above, in the first and second embodiments, since the zinc-based hot-dip galvanizing used has a low aluminum content, a sufficient rust prevention effect is obtained by the chromate treatment.

(Comparative Embodiment 7) First, a copper plating film was formed on the joint portion 11 of the iron member 1. This plating treatment was performed through a usual method, that is, steps of degreasing, washing with water, electrolysis, washing with water, and drying. The electrolysis conditions at that time are as shown in Table 2, and the electrolysis time was 1 to 3 minutes.

[0024]

[Table 2]

Next, the joint portion 11 of the iron member 1 where the copper plating film was formed was immersed in molten solder, and ultrasonic vibration was applied to the joint portion. As the molten solder, zinc-5% aluminum hot-dip plating is used, and the frequency of the ultrasonic wave is about 17.6.
KHz. Thereby, the to-be-joined part 11 of the iron member 1
Then, a zinc plating film was formed. On the other hand, a galvanized film was also formed on the joint portion 41 of the aluminum member 4. Then, the galvanized films of the two members 1 and 4 were brought into contact with each other, ultrasonic vibration was applied to the corresponding contact points to melt the two galvanized films, and the two members 1 and 4 were joined.

(Joint Strength Test) In order to evaluate the joint strength of the joint portion 5 of both members 1 and 4 in Embodiments 1 and 2 and Comparative Embodiment 7, the shear stress was measured for the joint portion 5. Table 3 shows the results.

[0027]

[Table 3]

As can be seen from Table 3, the bonding strength in the first and second embodiments is higher than the bonding strength in the comparative example 7 which is conventionally known. That is, in Embodiments 1 and 2, the bonding strength obtained conventionally is not impaired.

(Embodiment 3) FIGS. 6 to 11 are longitudinal sectional views showing each step of a method for bonding an iron member and an aluminum member according to this embodiment. Hereinafter, the joining processing method of the present embodiment will be described. In addition, SS400 is used as the iron member.
And A5052 as an aluminum member.

First, after the entire surface of the iron member 1 is degreased, electrogalvanizing is performed to form a galvanized film 32 as shown in FIG.

Next, the bonded portion 11 of the iron member 1 is immersed in the flux for 30 seconds and dried, and the flux 2 is adhered to the surface of the galvanized film 32 of the bonded portion 11 as shown in FIG. Was.

Next, as shown in FIG. 8, the bonded portion 11 to which the flux 2 has adhered is immersed in a bath of zinc-based hot-dip plating 3 at 450 ° C. for 30 seconds, and as shown in FIG. The zinc plating film 31 is formed on the surface of the zinc plating film 32 at the location 11.
Was formed. Here, the zinc-based hot-dip plating 3 having an aluminum content of 0.2% by weight, that is, zinc-
0.2% aluminum hot-dip plating was used.

Next, as shown in FIG. 10, the welded portion 41 of the aluminum member 4 is brought into contact with the galvanized film 31 of the welded portion 11 of the iron member 1, and ultrasonic vibration is applied to the contacted portion. In addition, the zinc plating film 31 was melted, and the two members 1 and 4 were joined. Reference numeral 5 denotes a joining portion between the two members 1 and 4.

Then, both members 1 and 4 are immersed in 10% nitric acid for 3 hours.
After immersion for 0 seconds and washing with water, as shown in FIG. 11, the aluminum member 4 and the joint portion 5 were subjected to chromate treatment by immersing in a bath of a chromate treatment solution 6 at room temperature for 120 seconds, washed with water, and washed at 60 ° C. And dried at room temperature for 12 hours. As the chromate treatment liquid 6, chromic anhydride 20 g / l, sulfuric acid 5 g / l, nitric acid 5 g / l,
A mixed acid composed of 15 g / l of phosphoric acid and 35 g / l of acetic acid was used.

(Embodiment 4) Zinc-based 1% aluminum hot-dip plating was used as the zinc-based hot-dip plating 3, and the other conditions were the same as those in Embodiment 3.

(Comparative Embodiment 8) A zinc-5% aluminum hot-dip plating was used as the zinc-based hot-dip coating 3, and the other conditions were the same as those in the third embodiment.

(Comparative Embodiment 9) A zinc-based 1% aluminum hot-dip plating was used as the zinc-based hot-dip plating 3, and
A zinc plating film 31 is formed in the same manner as
4 were joined. No subsequent chromate treatment was performed. The thickness of the zinc plating film 31 was 6 μm.

(Rust Prevention Effect Test) In order to evaluate the rust prevention effect of the joint 5 of the members 1 and 4 in Embodiments 3 and 4 and Comparative Embodiments 8 and 9, a salt spray test was performed on the joint 5. Table 4 shows the results. The display in Table 4 is
-: Not measured, x: poor, Δ: good.

[0039]

[Table 4]

The following can be seen from Table 4. (i) In Comparative Example 9 in which the chromate treatment was not performed, even though the aluminum content in the zinc-based hot-dip plating was the same as that in Embodiment 4, even generation of white rust could not be prevented. (ii) When the comparative embodiment 8 is compared with the embodiments 3 and 4, in the comparative embodiment 8, white rust is generated because the aluminum content of the zinc-based hot-dip plating is large despite the chromate treatment. Even that could not be prevented. (iii) From the above, in Embodiments 3 and 4, since the aluminum content of the zinc-based hot-dip plating used is small, a sufficient rust prevention effect is obtained by the chromate treatment.

(Joint Strength Test) In order to evaluate the joint strength of the joint 5 of the members 1 and 4 in Embodiments 3 and 4 and Comparative Embodiment 7, the shear stress was measured for the joint 5. Table 5 shows the results.

[0042]

[Table 5]

As can be seen from Table 5, the bonding strength in Embodiments 3 and 4 is higher than the bonding strength in Comparative Example 7 which is conventionally known. That is, in Embodiments 3 and 4, the bonding strength conventionally obtained is not impaired.

(Alternative Embodiment) In the first embodiment, the galvanized film 31 formed by the hot-dip galvanizing process is formed on the entire surface of the iron member 1, but the galvanized film 31 is formed at least at the portion 11 to be joined. Just do it. In the third embodiment, the galvanized film 32 formed by the electrogalvanizing process is formed on the entire surface of the iron member 1, but the galvanized film 32 may be formed at least at the joint portion 11. In the third embodiment, the galvanized film 31 formed by the hot-dip galvanizing process is formed at the portion 11 to be joined of the iron member 1. However, the galvanized film 31 only needs to be formed at least at the portion 11 to be joined. It may be formed on the entire surface of the member 1.

[0045]

As described above, according to the method for bonding an iron member and an aluminum member according to claim 1 or 2,
Sufficient rust prevention treatment can be performed on the joint portion between the two members without impairing the joint strength.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a state in which a flux is attached to the entire surface of an iron member in Embodiment 1.

FIG. 2 is a longitudinal sectional view showing a step following FIG. 1 in which a zinc-based hot-dip plating process is performed on the entire surface of the iron member.

FIG. 3 is a longitudinal sectional view showing a state subsequent to FIG. 2, in which a galvanized film is formed on the entire surface of the iron member by hot-dip galvanizing.

FIG. 4 is a longitudinal sectional view showing a state subsequent to FIG. 3, in which an iron member and an aluminum member are joined.

FIG. 5 is a longitudinal sectional view showing a step following FIG. 4 in which a chromate treatment is performed on a joint portion between both members.

FIG. 6 is a longitudinal sectional view showing a state in which a galvanized film is formed on the entire surface of the iron member by electrogalvanizing in Embodiment 3.

FIG. 7 is a vertical cross-sectional view showing a state following the step shown in FIG. 6, in which a flux is attached to a portion to be joined of the iron member;

FIG. 8 is a longitudinal sectional view showing a step following FIG. 7 in which a zinc-based hot-dip plating process is performed on a portion to be joined of the iron member.

FIG. 9 is a vertical cross-sectional view showing a state following the step shown in FIG. 8, in which a galvanized film is formed by a hot-dip galvanizing process on a portion to be joined of the iron member.

FIG. 10 is a longitudinal sectional view showing a state following the step of FIG. 9 in which the iron member and the aluminum member are joined to each other.

FIG. 11 is a longitudinal sectional view showing a step following FIG. 10 in which a chromate treatment is performed on a joint portion between both members.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Iron member 2 Flux 3 Zinc-base hot-dip plating 4 Aluminum member 5 Joining part 6 Chromate treatment liquid 11,41 Joined part 31 Zinc plating film (by hot-dip galvanizing treatment) 32 Zinc plating film (by electro-galvanizing treatment)

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ identification symbol FI // B23K 103: 20 B23K 103: 20 (58) Investigated field (Int.Cl. ⁷ , DB name) B23K 20/10

Claims (2)

(57) [Claims] At least a portion to be joined on a surface of an iron member,
After the flux is applied, a zinc-based hot-dip coating process is performed to form a zinc-plated film, and a hot-dip plating process is performed. The bonded portion of the aluminum member is brought into contact with the zinc-plated film of the bonded portion of the iron member. The method includes the steps of: joining the two members by melting the galvanized film by applying vibration; and performing a chromate treatment on a joint portion between the two members, and a rust prevention process. A method for joining an iron member and an aluminum member, wherein zinc-based hot-dip plating of 0.2 to 1% by weight is used. 2. The method according to claim 1, wherein at least a portion to be joined on the surface of the iron member is
Forming a galvanized film by performing electrogalvanizing
An electroplating process is provided in advance, and in the next hot-dip plating process, a zinc-based hot-dip coating process is performed after applying a flux to at least a galvanized film at a portion to be joined of the iron member to form a zinc-plated film. The method for bonding an iron member and an aluminum member according to claim 1.