JPH05185253A - Friction press welding method for different metallic pipe - Google Patents

Abstract

PURPOSE:To provide the method which can join an aluminum pipe and a steel pipe by friction press welding. CONSTITUTION:The aluminum pipe 1 and the steel pipe 2 are joined by friction press welding via an annular insert material 3 which is made of a fiber reinforced metal consisting of aluminum as a base material and stainless steel fibers as a reinforcing material and is included with the same kind of the materials as the mating materials in the surfaces to be joined at the time of joining the aluminum pipe and the steel pipe by the friction press welding. The aluminum pipe and the steel pipe are easily and securely joined by the friction press welding. The method is appliable to the friction press welding of generally different kinds of metallic pipes to each other and has a wide application range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction welding method for dissimilar metal pipes, and more particularly to a method for joining an aluminum pipe and a steel pipe by friction welding through an insert material.

[0002]

2. Description of the Related Art When joining an aluminum material such as an aluminum pipe and a steel material such as a steel pipe, various methods have been proposed because aluminum and steel cannot be easily and firmly alloyed and joined. There is also a joining method utilizing mechanical fitting by press-fitting one of the aluminum pipe and the steel pipe into the other, for example, JP-A-63-63.
No. 104790, when joining an aluminum pipe and a steel pipe, the inner diameter of the aluminum pipe is made smaller than the outer diameter of the steel pipe, the aluminum pipe is fixed, and the steel pipe having a tapered tip is rotated to form a joining surface. A method is disclosed in which the inner wall of the aluminum pipe is partly softened by bringing them into contact with each other to insert pressure, and then the pressure is further applied after the rotation of the steel pipe is stopped to join.

[0003]

By the way, Japanese Patent Laid-Open No. Sho 63-63
According to the method disclosed in Japanese Patent Laid-Open No. 104790, a structure in which a steel pipe is press-fitted into an aluminum pipe is formed.
The joint formed in this way has a problem that the mechanical strength of the joint tends to decrease when the temperature rises when it is used, because the thermal expansion coefficient of aluminum is larger than that of steel. ..

The present invention is intended to solve the above-mentioned problems of the prior art. The object of the present invention is to have a wide range of applications and to easily and firmly join an aluminum pipe and a steel pipe by friction welding. To provide a method.

[0005]

A friction welding method for dissimilar metal pipes of the present invention comprises aluminum as a base material and stainless steel fibers as a reinforcing material when joining an aluminum pipe and a steel pipe by friction welding. It is characterized in that it is joined by friction welding through a ring-shaped insert material made of fiber reinforced metal and containing the same material as the mating material on the surfaces to be joined.

The size of the aluminum tube (inner diameter and outer diameter,
The length) and the shape (for example, straight pipe, curved pipe, etc.) are not particularly limited and are selected according to the application. The aluminum tube means what is usually called an aluminum tube, for example, one containing aluminum as a main component and a small amount of other components.

Similar to the aluminum pipe, the steel pipe is not particularly limited in size and shape and is selected according to the application. The steel pipe means not only a carbon steel pipe but also a special steel pipe containing nickel, chromium, manganese or the like.

The size of the aluminum pipe and the size of the steel pipe,
In addition, it is easier for the aluminum pipe and the steel pipe to have the same shape for friction welding, but they may be different from each other.

The insert material is made of fiber reinforced metal consisting of aluminum as a base material and stainless steel fibers as a reinforcing material. Here, aluminum means not only pure aluminum as in the case of the aluminum tube, but also what is usually called aluminum, for example, aluminum containing aluminum as a main component and a small amount of other components.

The stainless steel fiber may be made of, for example, a SUS material according to JIS standard. The average length and average diameter of the fibers are selected so as to obtain the desired bonding strength.

If the volume ratio of the stainless steel fiber in the insert material is too large or too small, the joining strength of the joining member, for example, the tensile strength will be lowered. Therefore, in order to obtain sufficient bonding strength (for example, tensile strength higher than that in the annealed state), it is preferable that the volume ratio of the stainless steel fibers in the insert material is 30 to 60%.

The composite state of the stainless steel fibers in the insert material is selected so that the surfaces to be joined contain the same material as the mating material. For example, it is preferable to orient the material in a direction substantially orthogonal to the diameter direction of the insert material.
Further, at least the surface to be joined with the steel pipe exposes a part of the stainless steel fiber, preferably one end or one end surface. As a method of manufacturing the insert material, a conventional molding method in manufacturing a fiber-reinforced metal, for example, a high pressure casting method can be used.

The size and shape of the ring-shaped insert material are appropriately selected according to the size and shape of the aluminum pipe and the steel pipe to be joined. For example, when the aluminum pipe and the steel pipe have the same inner diameter and outer diameter, the inner diameter and outer diameter of the ring-shaped insert material are usually the same. That is, the inner diameter and the outer diameter of both ends of the ring-shaped insert material may be the same or different.

As means for joining the aluminum pipe and the steel pipe by friction welding through the insert material, conventional means in this field such as fixing means and rotating means can be used. Further, the specific operation for the friction pressure contact may be a conventional operation. That is, one of the two members to be frictionally pressure-bonded is fixed to, for example, a fixing jig, and the other is fixed to, for example, a rotation shaft, and the surfaces to be bonded are pressure-welded while being rotated to bond the bonding portions. .. Hereinafter, this operation is repeated a desired number of times to join the whole and obtain a joint.

[0015]

The aluminum in the insert material contributes to the joining surface between the insert material and the aluminum pipe, and the stainless steel fiber in the insert material contributes to the joining by friction welding at the joining surface between the insert material and the steel pipe.

[0016]

The present invention will be described in more detail by the following examples.

As shown in FIG. 1, the outer diameter is 38 mm and the wall thickness is 4 m.
m, a predetermined length of aluminum tube 1 (Material: JIS A6
061) and an outer diameter of 38 mm, a wall thickness of 4 mm, and a predetermined length of steel pipe 2 (material: JIS S45C) are joined by friction welding through an insert material 3 having an outer diameter of 38 mm, a wall thickness of 4 mm, and a length of 15 mm. And got a joint. Friction welding between the aluminum pipe 1 and the steel pipe 2 is performed by a conventional method, that is, a brake method, and the main friction welding condition in this case is friction pressure P ₁ = 2.5 kgf / m on the aluminum pipe 1 side.
m ² , upset pressure P ₂ = 5 kgf / mm ² , friction offset μ ₁ = 2 mm, and P ₁ = 4 kgf on the steel pipe 2 side.
/ Mm ² , P ₂ = 8 kgf / mm ² , and μ ₁ = 2 mm.

FIG. 2A is a view of the insert material 3 as seen from a direction orthogonal to the length direction. Further, FIG. 2B is a view of the insert material 3 as seen from the surface side to be joined to the steel pipe 2. In the drawing, 4 indicates aluminum and 5 indicates SUS fiber. It can be seen that the SUS fiber 5 is oriented in the length direction of the insert material 3.

The insert material 3 is made of pure aluminum as a base material and stainless steel (SU) as a reinforcement material.
S) Fiber (material: JIS SUS304, average diameter 10)
μm, average length 15 mm) and the specified mold,
It was manufactured by compounding using a high pressure casting method. The main production conditions were a SUS fiber preheating temperature of 200 ° C., an aluminum melt temperature of 750 ° C., a mold temperature of 350 ° C., and a mold pressure of 800 kgf / cm ² .

As shown in Table 1, insert materials 3 having various SUS fiber volume ratios (volume ratios of SUS fibers 5 in the insert material 3) were manufactured, and the aluminum pipes were manufactured by the above method using the insert materials 3. A joint was obtained from 1 and the steel pipe 2.

[Table 1]

Tensile Test FIG. 3 shows a joint portion (half side with respect to the center line in the length direction) of the joint manufactured by the above method. A tensile test in the lengthwise direction was performed on each joint obtained in the examples, and it was found that the joints were broken at three portions or portions or portions in FIG. Here, the part is aluminum tube 1 and insert material 3
Shows the joining interface with the, the part shows the joining interface between the insert material 3 and the steel pipe 2, and the part shows the part near the part of the aluminum pipe 1.

The tensile test results are summarized in FIG. Figure 4 is S
US fiber volume ratio (%; horizontal axis) and tensile strength σ _B (kgf /
mm ² ; vertical axis). Note that σ _B is a value obtained by dividing the maximum load until the joint breaks by the cross-sectional area of the pipe.

From FIG. 4, SUS fiber volume ratio 40-55%
Then, the fractured part is the part of FIG. 3, and the fracture strength of the joint in this case is not as high as σ _B (about 31.5 kgf / mm ² ) of the aluminum 4 which is the base material of the insert material 3, but in the figure This is sufficiently larger than the annealed state of aluminum (σ _B = 12.5 kgf / mm ² ) shown by the broken line, which indicates that good joining was performed in view of the breaking strength.

That is, in the above-mentioned case, FIG.
As shown in (state of SUS fiber volume ratio 40%), aluminum 4 and aluminum tube 1 which are base materials of the insert material 3
And are mixed and are joined firmly at the joint interface 6. Both the insert material 3 and the aluminum pipe 1 have a material flow in the vicinity of the joint interface 6 in the direction in which centrifugal force is applied during friction welding. Further, in the portion of FIG. 3, the SUS fiber 5 which is the reinforcing fiber of the insert material 3 and the steel pipe 2 are similarly firmly bonded together.

Further, from FIG. 4, the breaking point was the portion of FIG. 3 when the SUS fiber volume ratio was 35% or less. In this case, it is considered that the content of aluminum 4 in the insert material 3 was increased and a lot of brittle intermetallic compounds such as FeAl ₃ , Fe ₂ Al ₅ and FeAl were generated in the part.

Further, when the volume ratio of the SUS fiber is 60% or more, the broken portion is the portion shown in FIG. In this case, since the content of the SUS fiber 5 in the insert material 3 was increased, the brittle metal of iron and aluminum as described above at the joint interface 7 as shown in FIG. 6 (state of 70% SUS fiber volume ratio). It is considered that a lot of intermetallic compounds were generated.

Thus, as is apparent from FIG. 4, when the SUS fiber volume ratio is 25% or less or 65% or more, the tensile strength in the longitudinal direction of the joint is lower than that of the annealed state of aluminum (material: A6061), and therefore larger than this. When the tensile strength in the longitudinal direction of the joint is desired, it is preferable to set the fiber volume ratio of the SUS fiber 5 in the insert material 3 to 30 to 60% as shown by the diagonal lines in FIG.

[0028]

The friction welding method for dissimilar metal pipes of the present invention comprises:
When joining an aluminum pipe and a steel pipe by friction welding, it is made of fiber reinforced metal consisting of aluminum as a base material and stainless steel fiber as a reinforcing material, and the surface to be joined contains the same material as the mating material. Since it is joined by friction welding through a ring-shaped insert material, the aluminum in the insert material at the joint surface between the insert material and the aluminum pipe, and the stainless steel in the insert material at the joint surface between the insert material and the steel pipe. The steel fibers each contribute to the joining by friction welding, and the aluminum pipe and the steel pipe can be joined easily and firmly by friction welding.

Further, since the stainless steel fibers in the insert material slightly protrude from the aluminum base material during friction welding and clean the surface of the mating material to be joined by scraping with a wire brush, the new surface preferable for joining is friction joined. Sometimes easily obtained.

Further, in the method of the present invention, by selecting various base materials and reinforcing materials constituting the insert material, for example, when aluminum is used as the base material and copper fiber or titanium fiber is used as the reinforcing material, aluminum is used. There is a possibility that it can be generally applied to friction welding of metal pipes of different types, such as a possibility of being applied to friction welding of a pipe and a copper pipe or a titanium pipe, and it has a wide range of applications.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a friction welding method for dissimilar metal pipes of the present invention.

FIG. 2 is an explanatory view of an insert material used in the method of the present invention.

FIG. 3 is a cross-sectional view showing a part of a joint portion of a joint joined by using the method of the present invention.

FIG. 4 shows a joint joined by using the method of the present invention,
It is a figure which shows the relationship between the SUS fiber volume ratio in an insert material, and tensile strength.

FIG. 5 shows a joint joined by using the method of the present invention,
It is explanatory drawing which shows the state of the joint interface of an aluminum pipe and insert material in case the SUS fiber volume ratio in an insert material is 40%.

FIG. 6 shows a joint joined using the method of the present invention,
It is explanatory drawing which shows the state of the joint interface of an aluminum pipe and insert material in case the SUS fiber volume ratio in an insert material is 70%.

[Explanation of symbols]

 1 Aluminum pipe 2 Steel pipe 3 Insert material 4 Aluminum 5 SUS fiber 6,7 Bonding interface part Bonding interface part between aluminum pipe and insert material Bonding interface part between insert material and steel pipe Part near aluminum pipe part

Claims (1)

[Reference number] C1029 [Claims] 1. When joining an aluminum pipe and a steel pipe by friction welding, a fiber-reinforced metal made of aluminum as a base material and stainless steel fibers as a reinforcing material is used, and a mating material is provided on the surface to be joined. A friction welding method for dissimilar metal pipes, characterized by joining by friction welding through a ring-shaped insert material containing the same material.