JPH1133711A - Joining method for aluminum material and steel material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and inexpensive method of joining together by soldering a joint of a steel member and a joint of an aluminum member using ultrasonic wave after brazing is made to the joint of the steel member, by which there is no necessity of masking like in plating treatment but applying a brazing filter metal only to the joint of the steel member is required. SOLUTION: A steel pipe 2 with a bearing layer 7 is inserted into a joint of the aluminum flange 1 and a solder is supplied from a space in heated condition. Joining is so carried out that ultrasonic wave is applied to the supplied solder under pressure. The thickness of the film formed by brazing is preferably not less than 1 μm for example, to prevent oxidation of the steel surface. Ultrasonic wave used when the brazed steel member and aluminum member are joined together with the solder is about 10-100 kHz frequency for example. The ultrasonic wave is applied for joining for 1-30 seconds, for example. The heating temperature in ultrasonic joining is about 380-500 deg.C, for example.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining an aluminum member and an iron member by soldering using ultrasonic waves. INDUSTRIAL APPLICABILITY The present invention can be applied to joining of an intake manifold, a water outlet pipe, and the like for a four-wheeled vehicle.

[0002]

2. Description of the Related Art As a joining method of an aluminum member and a dissimilar metal member, for example, as described in JP-A-5-185217, the surface of the dissimilar metal member is previously subjected to a plating treatment such as copper plating. Later, a method of performing soldering is known. However, since this method includes a plating process, the number of steps is large and the cost is high. That is, the plating process includes the steps of degreasing, washing with water, pickling, washing with water, electrolysis, washing with water, and drying.

FIG. 4 shows a plating process, which is a pretreatment process before joining an iron surge tank made of an iron pipe, which is a component part of the composite intake manifold, to an aluminum flange. FIG. 4 (a)
Shows the case where the entire part is plated, and (b) shows the case where only the joint with the aluminum flange is plated.

In FIG. 4A, a plating solution 9 in a plating tank 8 is immersed in a joint of an iron pipe 2 and an iron surge tank 3. When plating is applied to the entire iron member in this way, it becomes difficult to perform rust prevention treatment after joining, and the plating solution is wasted. In FIG. 4B, the surface of the joint between the iron pipe 2 and the surge tank 3 made of iron is masked 10 except for the joint with the aluminum flange. When plating is performed only on the joints in this way, although there is no hindrance to the rust prevention treatment after joining with the aluminum flange, the masking cost is extra and the cost is high.

[0005] On the other hand, even if an attempt is made to join by soldering using ultrasonic waves without plating, the oxide film on the surface of the iron member hinders soldering and cannot be joined. Even if the joining is performed by brazing without plating, the brazing temperature of the iron-based brazing material is high, so that the aluminum member is melted.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for joining an aluminum member and an iron member without plating as a pretreatment.

[0007]

According to the method of joining an aluminum member and an iron member according to the present invention, after brazing a joint portion of an iron member, the joint portion and the joint portion of the aluminum member are bonded to each other by using ultrasonic waves. It is characterized by soldering. In the bonding method of the present invention, the brazing can be performed under a reducing atmosphere or using a flux. The joining method of the present invention may further include a step of joining the other joint part and the joint part of the other iron member while brazing the other joint part of the iron member.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As the iron member used in the present invention,
Steel, stainless steel, cast iron and the like can be mentioned, and among them, steel is preferably used in terms of joining strength. Examples of the aluminum member used in the present invention include a wrought material, a cast material, a die-cast material, and the like. Among them, the die-cast material is preferably used from the viewpoint of cost.

[0009] Examples of the brazing material used in the present invention include Cu-based, Ag-based, and Ni-based brazing materials, which are iron-based brazing materials, and solder materials for iron members. Among them, Cu
A brazing filler metal is preferably used in terms of bonding strength.
Further, as the characteristics of the brazing material, those which can be alloyed with the ultrasonic soldering material for aluminum (Al-based solder material) are preferable. Examples of the Cu-based brazing material include JIS BCu-based, BCuZn-based, and BCuP-based brazing materials. Examples of the Ag-based brazing material include JIS BAg-based and BVAg-based brazing materials. Examples of Ni-based brazing materials include JIS BN
i-type can be mentioned. As a solder material for iron members, for example, Sn-Pb-based solder (JIS H60A
Etc.) and Pb-Sn based solder (JIS H20A etc.).

[0010] Brazing is performed to remove an oxide film on the surface of the iron member and to protect the surface. As a brazing method, there are a method of performing brazing in a furnace in a reducing atmosphere or in a vacuum, and a method of performing brazing using a flux in the atmosphere. In the case of brazing in a furnace in a reducing atmosphere or in a vacuum, the temperature in the furnace depends on the melting point of the brazing material (600 to 1).
(About 100 ° C.) plus 10 to 200 ° C.
The heating time is about 10 to 60 minutes. In order to make the atmosphere be a reducing atmosphere, for example, a carbon monoxide gas, a propane modified gas, a butane gas, or the like may be continuously supplied. After brazing in a furnace, there is no need to perform post-treatment such as water washing.

In the case of brazing using a flux in the atmosphere, the flux and the brazing material are adhered to the joint of the iron members, and then, in a furnace, in the atmosphere, using a high-frequency induction for 600 to 1 hour.
Heat to about 100 ° C. The heating time is about 5 to 30 minutes. Here, the flux refers to a substance used to make the joint easily wet by brazing at the time of brazing, and specifically, a flux containing borax, boric acid, hydrochloric acid, or the like as a main component is used. After brazing, a residue treatment of the brazed portion is performed before joining with the aluminum member.

[0012] The thickness of the film formed by brazing is
In order to prevent oxidation of the iron surface, the thickness is preferably 1 μm or more. The ultrasonic wave used when joining the brazed iron member and the aluminum member by soldering has a frequency of about 10 to 100 kHz. Ultrasonic waves are applied for about 1 to 30 seconds for bonding. The heating temperature at the time of ultrasonic bonding is about 380 to 500 ° C.

The solder used in the ultrasonic bonding includes, for example, Zn-Al based, Zn-Sn based, Z
An n-Cd type or the like can be given. In the present invention,
When joining the iron member and the aluminum member at the same time as joining the iron members, one joint of the iron member is brazed as a pre-treatment for ultrasonic joining with the aluminum member, and the other of the iron member is brazed. What is necessary is just to braze a joining part similarly to another iron member.

Next, a description will be given of an example of manufacturing a composite intake manifold. Figure 1 shows a composite intake
Aluminum flange (die-cast product) 1, iron pipe 2, iron surge tank 3 which is a component of manifold
Is shown. One end of the iron pipe 2 is joined to the aluminum flange 1, and the other end is joined to the iron surge tank 3.

FIG. 2 shows the respective brazing steps when a flux is used for brazing and when no flux is used. In FIG. 2, a brazing material 4 is applied to each joint between the iron pipe 2 and the iron surge tank 3. When the flux is not used together with the brazing material 4, it is heated in a reducing furnace 5 in a reducing atmosphere and then joined to an aluminum flange. When a flux is used together with the brazing material, after heating in an air furnace 6 open to the atmosphere, a residue treatment is performed.
Join with aluminum flange.

FIG. 3 shows a cross section of a joint between the aluminum flange 1 and the iron pipe 2 when joining by ultrasonic waves. In FIG. 3, an iron pipe 2 having a brazing layer 7 is inserted into a joint portion of an aluminum flange 1, and solder is supplied from the gap under heating (about 380 to 500 ° C.). Pressing the supplied solder (1MP
(approximately a to 10 MPa), an ultrasonic wave is applied, and bonding is performed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to the joining of an intake manifold for a four-wheeled vehicle will be described below. 1. Pretreatment Step (Brazing) Copper brazing (composition: 75% by weight of copper, 25% by weight of binder, melting point: 1083 ° C, trade name: joint at both ends of iron pipe (STKM11A) and joint of iron surge tank) (Kappa brazing paste M25, manufactured by Shinwa Co., Ltd.). After the application, this was placed in a reducing furnace that constantly supplies carbon monoxide gas, and held at 1120 ° C. for 60 minutes to perform brazing. As a result, the oxide film on the surface of the joint was removed, and a copper film having a thickness of 10 μm was formed. Simultaneously with the formation of the copper film, the iron pipe and the surge tank were joined.

[0018] 2. Joining process by ultrasonic soldering The brazed iron pipe is fitted to an aluminum flange (ADC12 die-cast material), and molten solder is supplied while heating, and ultrasonic waves (output: 360 W, frequency: 19.6 kHz) are applied. Bonding was performed by applying a voltage for 10 seconds. As a solder, zinc solder for aluminum (Zn
-5% Al, JIS AH-Z95A) was used. As a supply method, a ring-shaped solder was placed at the upper end of the joint, and this was heated to 420 ° C. by high-frequency induction heating.
It melted and was supplied to the joint.

The bonded intake manifold was subjected to a pressure leak test and a vibration test. The pressure leak test was performed by immersing the work in water and applying a pressure method (pressure: 3 kg / cm ² ). As a result, no leakage was observed at the joint. In the vibration test, the flange side was fixed and the surge tank side was -3.
The test was performed by applying a tension / compression load in a load range of 00 to 300 kgf. As a result, the number of repetitions N = 1.8
The steel pipe side was broken at 6 × 10 ⁶ . It was found that the joint had a fatigue strength higher than that of an iron pipe.

[0020]

According to the present invention, in joining the aluminum member and the iron member, there is no need for masking unlike plating, and the brazing material may be applied only to the joint of the iron member. Can be joined. In addition, since the brazing material film is formed only at the joint, there is no hindrance to the rust prevention treatment other than at the joint. In addition, by brazing under a reducing atmosphere or using a flux, the oxide film on the surface of the iron member can be removed without performing pickling as in plating. Further, since brazing is performed only on the iron member, there is no possibility that the aluminum member is melted by the high temperature during brazing.
Furthermore, in the case where the joining of the iron members is also performed at the same time, the pretreatment of the ultrasonic joining of the aluminum member and the iron member and the joining of the iron members can be performed in one step of brazing, which is efficient and low. Cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing components of an intake manifold.

FIG. 2 is a view showing a brazing process of an intake manifold.

FIG. 3 is a diagram showing a cross section of a joint between an aluminum flange and an iron pipe during ultrasonic welding.

FIG. 4 is a view showing a plating step of a part of an intake manifold.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum / flange 2 Iron pipe 3 Iron surge tank 4 Brazing material 5 Reduction furnace 6 Atmosphere furnace 7 Brazing layer 8 Plating tank 9 Plating solution 10 Masking

Claims (3)

[Claims] 1. A method of joining an aluminum member and an iron member, comprising: after brazing the joint of the iron member, soldering the joint and the joint of the aluminum member using ultrasonic waves. . 2. The method according to claim 1, wherein the brazing is performed in a reducing atmosphere or using a flux. 3. The aluminum according to claim 1, further comprising a step of brazing the other joint of the iron member and joining the other joint and the joint of the other iron member at the same time. Joining method of member and iron member.