JPH0576925A - Multi-hole tube manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method for efficiently producing a multi-hole tube having excellent pressure resistance and corrosion resistance and excellent heat exchange efficiency. [Structure] A partition fin 13 is supplied from a through hole 12 provided in a mandrel 9 of a composite die including a mandrel 9 having a through hole 12 in an axial center and a die 10 arranged on the outer periphery of the mandrel 9 and the mandrel 9 is provided. A metal pipe 11 is extruded through a gap between the die 10 and the die 10 to manufacture a multi-hole pipe in which the partition fin 13 is provided inside the metal pipe 11. [Effect] Excellent heat exchange efficiency because the interior is partitioned by the partition fins 13. Manufacture of metal pipe 11 and metal pipe
Since the partition fins 13 can be fixed to the 11 at the same time, the productivity is high. Further, since the metal pipe of the outer layer is manufactured by the extrusion method, it is seamless and has excellent corrosion resistance and pressure resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multi-hole tube used in a heat exchanger or the like.

[0002]

2. Description of the Related Art Conventionally, a multi-hole pipe used for a heat exchanger or the like has a plurality of holes 15 formed vertically in a metal plate-like body 14 as shown in the sectional view of FIG. It is provided, and the body to be cooled is passed through this hole 15, and the outside is cooled with cooling water before use. Further, such a multi-hole pipe has been manufactured by an extrusion method using a composite die in which a mandrel 9 having a plurality of convex protrusions at its tip is arranged in the hole of the die 10 as shown in FIG. However, in recent years, as part of the improvement of heat exchange efficiency, the inside of the multi-hole pipe has been partitioned by using the partitioning fin 13 having a complicated structure as shown in FIG. The method was difficult to manufacture. For this reason, multi-hole pipes with complicated partition fins are used to manufacture metal pipes by the electric resistance welding method or roll forming method in which a band-shaped metal sheet is formed into a cylindrical shape and the edges are welded. However, it was manufactured by the method of brazing the partition fin in this metal pipe.

[0003]

However, in such a manufacturing method, the productivity is low and the pressure resistance is poor because the seam remains in the length direction of the metal pipe, and the seam easily corrodes and is reliable. There was a problem of lack of sex.

[0004]

The present invention has been made as a result of intensive studies in view of such a situation. The object is to have good pressure resistance and corrosion resistance, and excellent heat exchange efficiency. Another object of the present invention is to provide a method for efficiently manufacturing a multi-hole tube. That is, the present invention is a method for manufacturing a multi-hole pipe in which a partition fin is internally provided in a metal pipe, which is a composite die including a mandrel having a through hole in its axial center and a die arranged on the outer periphery of its tip. The inner partition fin is supplied from the through hole provided in the mandrel, the metal pipe is extruded from the gap between the mandrel and the die, and the inner partition fin is closely attached to the metal pipe and internally provided. It is what

The method of the present invention will be specifically described below with reference to the drawings. FIG. 1 is an explanatory view of a main part of a rotary wheel type extrusion method showing an embodiment of the method of the present invention. The rotary wheel type extrusion method uses the endless groove 2 provided on the periphery of the rotary wheel 1.
And a fixed shoe block 3 that engages with the endless groove 2
To form a passage 4 by supplying a metal material 5 to be an outer pipe to the passage 4, and by frictional resistance generated between the metal material 5 and the inner surface of the groove 2 as the rotary wheel 1 rotates. An extruding pressure is generated in the metal material 5, and the extruding pressure is further increased in the sub-container 7 provided inside the abutment 6 and in the collecting chamber 8 at the back thereof to a mandrel 9 arranged in the collecting chamber 8. This mandrel 9
The metal material 5 is extruded in a pipe shape from a gap between the die 10 arranged on the outer periphery of the tip end portion, and a middle partition fin 13 is inserted into the metal pipe 11 through a through hole 12 provided at the axial center of the mandrel 9. It is a method of supplying and adhering both to be extruded.

Next, a method of closely attaching the partition fins to the metal pipe to internally install them will be specifically described with reference to the drawings. FIG. 2 is an explanatory diagram of a composite die including a die and a mandrel. The front and rear arrangement positions of the die 10 and the mandrel 9, that is, the protruding length of the tip of the mandrel into the die hole is variously changed so that the inner diameter of the metal pipe 11 to be extruded is equal to or less than the outer diameter of the intermediate partition fin 13. To adjust the close contact (Fig. A), or to make the tip end surface of the mandrel 9 thin by forming a taper on the outer circumference of the tip end of the mandrel 9, A method to close the clearance between the inner surface of the metal pipe 11 and the heat shrinkage of the metal pipe 11 to bring them into close contact (Fig. B).
Etc. apply.

Further, a method of compressing the post-extrusion multi-hole pipe or a method of applying a brazing material to the intermediate partition fins and then brazing by heating at the time of extrusion or later in a heating furnace The adhesion can be further improved by a method or the like. In the method of the present invention, in addition to the above-mentioned rotary wheel type extrusion method, the extrusion method is an ordinary extrusion method or any extrusion method such as Schlehmann extrusion method in which a plurality of containers are provided so that extruded materials can be continuously supplied. The law is applicable. Further, as the partition fins provided inside the metal pipe, partition fins 13 having various shapes as shown in FIGS. Further, in FIG. 4, the above-mentioned partition fin 13 is a metal pipe.
A multi-hole tube inscribed in 11 is illustrated.

[0008]

According to the method of the present invention, the partition fin is supplied from the through hole provided in the mandrel of the composite die including the mandrel having the through hole in the shaft center and the die arranged on the outer periphery of the mandrel, and the mandrel and the die. Since the metal pipe is extruded from the gap of and the inner partition fin is internally provided in the metal pipe, the internal surface area becomes large and the thermal efficiency is improved, and the metal pipe manufacturing and the middle partition fin for the metal pipe are improved. The internal pipe can be formed at the same time and the productivity is high, and since the metal pipe of the outer layer is manufactured by the extrusion method, it is seamless and has excellent corrosion resistance and pressure resistance.

[0009]

EXAMPLES The method of the present invention will be described in detail below with reference to examples. Example 1 By the rotary wheel type extrusion method shown in FIG. 1, a multi-hole tube having a shape shown in FIG. 4 having a cross-sectional dimension of 2 mm in length and a width of 20 mm was manufactured. The intermediate partition fin 13 was made of high-purity Al. The material of the metal pipe 11 is 12 mmφ Al
A rough line was used. The protrusion length of the tip of the mandrel 9 into the hole of the die 10 is usually 5 mm, but this is 0.5 m.
m and 1.0 mm so that the inner diameter of the metal pipe 11 extruded through the gap between the die 10 and the mandrel 9 is smaller than the outer diameter of the tip of the mandrel 9,
The intermediate partition fin 13 was brought into close contact with the inner surface of the metal pipe 11. Further, the thickness of the tip surface of the mandrel 9 is set to a normal thickness of 0.6 mm.

Example 2 In Example 1, the thickness of the tip surface of the mandrel 9 was set to 0.
Example 1 except that the thickness was reduced to 1 mm, and the tip of the mandrel 9 was disposed in the hole of the die 10 so as to project a normal length of 5 mm.
A multi-hole tube was manufactured by the same method as described above. The above-mentioned multi-hole pipe immediately after extrusion had a clearance of about 0.15 mm between the inner surface of the metal pipe 11 and the outer diameter of the partition fin 13.
As the metal pipe 11 on the outer periphery contracted as it cooled, it became in close contact with the inner partition fins 13, but
In order to further improve the adhesion, the multi-hole pipe was subjected to drawing with a surface reduction rate of 10%. Example 3 A multi-hole tube was manufactured by the same method as in Example 1 except that the multi-hole tube obtained in Example 1 was subjected to drawing with a surface reduction rate of 10%. Example 4 In Example 1, the metal pipe 11 of the intermediate partition fin 13 was used.
A multi-hole tube was manufactured by the same method as in Example 1 except that the brazing material was applied to the required portions in contact with the inner surface of the. The pressure resistance and corrosion resistance of each multi-hole tube thus obtained were investigated. The pressure resistance was evaluated by sealing one end of a multi-hole tube and applying water pressure from the other end to rupture the tube itself or peeling the partition fin and the metal pipe. The corrosion resistance was evaluated by performing a salt spray test and determining the degree of pitting corrosion. For comparison, a multi-hole pipe having the same shape and size was manufactured by the conventional electric resistance welded pipe method, and the same investigation was conducted. The results are shown in Table 1.

[0011]

[Table 1]

As is clear from Table 1, all the products of the present invention (Nos. 1 to 5) were excellent in pressure resistance and corrosion resistance. In Example 1, the projecting length of the mandrel into the die hole was changed to two ways of 0.5 mm and 1.0 mm. However, in the former case, the inner diameter of the metal pipe to be extruded becomes smaller, Excellent adhesion and improved pressure resistance. The multi-hole tube is extruded and then drawn (No. 3 and 4), and the brazing material is applied to the required parts of the partition fins and compound extruded (No. 5). It had excellent properties. On the other hand, the comparative example product (No.
In 6), the seam of the metal pipe became a neck, and both the pressure resistance and the corrosion resistance were low.

[0013]

As described above, according to the method of the present invention, it is possible to efficiently manufacture a multi-hole pipe having excellent pressure resistance and corrosion resistance, and partitioning the inside with intermediate partition fins to improve heat exchange efficiency. , Has a remarkable industrial effect.

[Brief description of drawings]

FIG. 1 is an explanatory view of a main part of a rotary wheel type extrusion method showing an embodiment of the method of the present invention.

FIG. 2 is an explanatory view showing an example of a mode of a composite die used in the method of the present invention.

FIG. 3 is a perspective view of a partition fin used in the method of the present invention.

FIG. 4 is an explanatory view of a multi-hole pipe having internal partition fins provided therein.

FIG. 5 is an explanatory view of a multi-hole pipe provided with a plurality of holes.

FIG. 6 is an explanatory view of a composite die for manufacturing a multi-hole pipe having a plurality of holes.

[Explanation of symbols]

 9 Mandrel 10 Die 11 Metal pipe 12 Through hole 13 Partition fin

Claims (1)

[Claims] 1. A method of manufacturing a multi-hole pipe in which a partition fin is internally provided in a metal pipe, which comprises a mandrel having a through hole in its shaft center and a die arranged on the outer periphery of its tip. The intermediate partition fin is supplied from the through hole provided in the mandrel, the metal pipe is extruded from the gap between the mandrel and the die, and the internal partition fin is closely attached to the metal pipe and is internally provided. Method for manufacturing multi-hole tube.