JPH0732010A - Production of thin aluminum tube - Google Patents

Abstract

PURPOSE:To produce a thin aluminum tube excellent in elongation characteristic. CONSTITUTION:After an aluminum tube 5 extruded with a comform extruder 1 is cooled in a cooling water bath 3, it is formed until a prescribed outer diameter with a driving roll device 21. The driving roll device 21 is arranged in multi stage with pair rolls consisting of a pair of driving vertical rolls in order to execute with circular shape working and a pair of non-driven lateral rolls in order to execute with oval working and arranged in multi-stage so that reductions between vertical rolls are gradually decreased and made to 2.5 to 4.5%. Because the working hardening in working time can be decreased in this method, the thin aluminum tube especially, excellent in bending and elongation characteristic can be produced.

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 an aluminum pipe, and more particularly to an improvement in a method for manufacturing a thin aluminum pipe having excellent bending and elongation characteristics.

[0002]

2. Description of the Related Art Aluminum pipes are used in various composite piping materials because of their excellent workability, moldability, corrosion resistance, and the like, and aluminum pipes are being widely used as the outer conductor of coaxial cables. .

Such a thin aluminum pipe is
It is formed by extruding it into a pipe shape by an extruder, or by forming an aluminum tape into a pipe shape and welding it, and then subjecting it to a predetermined size.

As a method of manufacturing the above-mentioned aluminum pipe, the extrusion method is excellent in terms of stability of the quality and productivity, and the aluminum pipe after extrusion is formed by a pipe drawing process using a die.

FIG. 4 shows a method for forming an aluminum pipe by such a conventional extrusion method and a pipe-expanding method using a die. Therefore, 1 is an extruder, 2 is an aluminum rod, 3 is a cooling water tank, and 4 is a circle. It is a die.

The extruder 1 is a conform extruder (Japanese Patent Publication No. 51-38316) developed by the British Nuclear Corporation.
This device is also called a rotary wheel type continuous extruder or a friction drive type extruder. As shown in FIG.
The extruder 1 is mainly composed of a rotating wheel 10 having a groove 10a formed on the outer peripheral surface thereof, a fixed shoe block 11 engaging with a part of the outer periphery of the rotating wheel, a die 12 and a plug 13. , Rotating wheel 10
The aluminum rod 2 supplied into the groove 10a generates frictional heat by the rotation of the rotary wheel 10 and is applied with high pressure to be extruded in a pipe shape from between the die 12 and the plug 13.

After being extruded, the aluminum pipe 5 is cooled in a cooling water tank 3 and then guided to a round die 4 through a dancer roll 6, and a pulling force is applied by a take-up machine 7, as shown in FIG. The aluminum pipe 5a is molded into a predetermined size. In the conventional manufacturing method by the extrusion method and the tube-expanding method using a die, there is an advantage that a thin aluminum pipe having excellent roundness and dimensional accuracy of the pipe can be formed.

[0008]

However, the aluminum pipe produced by the extrusion method and the tube-expanding method using a die is inferior in mechanical properties, particularly elongation property, to the aluminum pipe produced by the welding method, so that it is difficult to bend. There is a problem that cracks are likely to occur in the pipe when the pipe is bent with a small curvature.

For example, while the elongation of the outer conductor by the welding method is about 20%, the elongation of the outer conductor by the extruding method and the tube-expanding method using a die is only about 5%.

The reason for this is that in the case of the extrusion method, reduction (drawing rate; when the outer diameters before and after processing are A and B, respectively, when the aluminum pipe is expanded by a die during the forming process of the aluminum pipe (A- B) x 100 / A
Expressed as (%). same as below. Is about 20 to 30%, it is known that the work hardening occurs due to strain and tension applied to the aluminum pipe during working.

The present invention has been made to solve the above problems, and in a method for manufacturing an aluminum pipe after extrusion to manufacture a thin aluminum pipe having a thickness of about 0.5 to 2 mm, the bending and It is an object of the present invention to provide a method for producing a thin-walled aluminum pipe capable of improving elongation characteristics.

[0012]

In order to achieve the above-mentioned object, the present invention is to extrude an aluminum pipe with a conform extruder to cool it, and then subject the aluminum pipe to a molding process to form a thin wall of a predetermined size. In the method for producing an aluminum pipe, the aluminum pipe after extrusion is formed by a drive roll device in which a set roll consisting of a vertical roll and a horizontal roll is arranged in multiple stages so that the reduction between the set rolls is sequentially reduced. It is a thing.

In the above-mentioned forming process, the aluminum pipes after extrusion are driven by arranging the assembly rolls composed of vertical rolls and horizontal rolls in multiple stages so that the reduction between the assembly rolls is 2.5 to 4.5%. It is possible to manufacture a thin-walled aluminum pipe having excellent bending and elongation characteristics by adopting a method of molding with a roll device.
In the above invention, the extruded aluminum pipe is formed by a driving roll device in which a set of vertical rolls and horizontal rolls are arranged in multiple stages. It is preferable in view of the configuration of the apparatus that the roll and the pair of non-driving lateral rolls for performing the oval processing are used.

As described above, (a) the reduction between the pair of rolls is arranged in multiple stages so as to gradually decrease, or
(B) By arranging in multiple stages so as to be 2.5 to 4.5% and forming by only roll forming, for example, in the case of pipe forming with a total reduction of 20 to 30%,
Thin-walled aluminum pipes with an elongation of ~ 18% can be produced.

[0015]

With the above construction, in the method for manufacturing a thin aluminum pipe of the present invention, the aluminum pipe after extrusion is processed by the drive roll device in which the assembly rolls including the vertical rolls and the horizontal rolls are arranged in multiple stages. The tension applied to the aluminum pipe during processing can be reduced, and as a result, work hardening can be reduced, so that the elongation characteristics of the aluminum pipe after molding are improved.

[0016]

EXAMPLE An example of the present invention will be described below.

FIG. 1 shows an outline of an apparatus 20 for manufacturing a thin-walled aluminum pipe used in the method of the present invention. 1 is a conform extruder, 2 is an aluminum rod, 3 is a cooling water tank, and 21 is a cooling water tank. Is a drive roll device. The same parts as those in FIG. 4 are designated by the same reference numerals.

In the apparatus 20 described above, the aluminum rod 2 supplied into the groove 10a of the rotary wheel 10 of the extruder 1 is heated by the frictional heat generated by the rotation of the rotary wheel 10 and is applied with a high pressure, so that the die 12 is pressed. And the plug 13 are extruded in a pipe shape.

The extruded aluminum pipe 5 is cooled in the cooling water tank 3 and then sent to the drive roll device 21 via the dancer roll 6 to be molded to a predetermined outer diameter and then taken by the take-up machine 7. .

As shown in FIG. 2, the drive roll device 21 includes a pair of drive vertical rolls 21a for circular processing.
And a pair of non-driving horizontal rolls 21b for performing the oval processing are arranged in multiple stages. Reduction between the pair of rolls (reduction between vertical rolls) is gradually reduced by (a). Or (b) 2.
It is arranged in multiple stages so as to be 5 to 4.5%. Figure 3
Shows an example of an aluminum pipe molded in this way, and FIGS. 9A and 9B show cross-sectional shapes of the aluminum pipe after circular processing and after oval processing, respectively.

Hereinafter, using the manufacturing apparatus 20 shown in FIG. 1,
A specific example in which a thin aluminum pipe is manufactured by the method described below will be described.

Concrete Example 1 An aluminum rod (3N) 2 was fed to the extruder 1,
Aluminum pipe 5 with an outer diameter of 13.4 mm and a thickness of 0.6 mm
Was extruded.

After cooling this aluminum pipe in the cooling water tank 3, a drive roll device 21 consisting of a set of eight rolls is provided.
Was molded to an outer diameter of 10.0 mm.

The reduction between the vertical rolls at this time is 5.
It was set to gradually decrease from 5% to 1.0%.

The total reduction added to the aluminum pipe 5 after the above extrusion was 25.4%.

The results of measuring the mechanical properties of the thin-walled aluminum pipe manufactured as described above are shown in Table 1.
Shown in.

[0027]

[Table 1] Specific Example 2 An aluminum pipe 5 was extruded in the same manner as in the specific example, the aluminum pipe was cooled in a cooling water tank 3, and then an outer diameter of 9.6 mm was obtained by a drive roll device 21 composed of an 8-stage assembly roll.
Molded up to.

The reduction between the vertical rolls at this time is 3.
It was set to a nearly constant value between 7% and 4.4%.

The total reduction added to the aluminum pipe 5 after the above extrusion was 28.4%.

The results of measuring the mechanical properties of the thin-walled aluminum pipe thus manufactured are shown in Table 1.
It was shown to.

Concrete Example 3 In the same manner as in Concrete Example 2, the aluminum pipe 5 is extruded,
After cooling this aluminum pipe in the cooling water tank 3, 1
An outer diameter of 9.
Molded to 8 mm.

The reduction between the vertical rolls at this time is 2.
It was set to a nearly constant value between 7% and 3.5%.

The total reduction added to the aluminum pipe 5 after the above extrusion was 26.9%.

The results of measuring the mechanical properties of the thin-walled aluminum pipe thus manufactured are shown in Table 1.
It was shown to.

Comparative Example Using the apparatus shown in FIG. 4, an aluminum pipe 5 was extruded in the same manner as in the specific example, the aluminum pipe was cooled in a cooling water tank 3, and then drawn out by a take-out machine 7 using a round die 4. A thin wall aluminum pipe was manufactured by subjecting it to pipe drawing by applying force. At this time, the inner diameter of the circular die 4 was 9.6 mm. Moreover, the total reduction added to the aluminum pipe 5 after the above extrusion is 28.
It was 4%. Table 1 shows the results of measuring the mechanical properties of the thin-walled aluminum pipe manufactured as described above.

[0036]

As described above, according to the method of manufacturing a coaxial cable of the present invention, it is possible to reduce the tension applied to the aluminum pipe and the work hardening during the forming process, and therefore the thin wall excellent in bending and elongation characteristics is obtained. Aluminum pipes can be manufactured.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an apparatus for manufacturing a coaxial cable used in the method of the present invention.

FIG. 2 is a schematic view showing an embodiment of the drive roll device of FIG.

FIG. 3 is a cross-sectional view of an aluminum pipe formed by the set roll of FIG.

FIG. 4 is a schematic view showing a conventional coaxial cable manufacturing apparatus.

FIG. 5 is a schematic sectional view of a conform extruder.

6 is a cross-sectional view showing a pulled-out state by the die of FIG.

[Explanation of symbols]

 1 ………… Conform extruder 2 ………… Aluminum rod 3 ………… Cooling water tank 5 ………… Aluminum pipe 7 ………… Take-off machine 21 ………… Drive roll device 21a …… Drive vertical roll 21b …… Non-drive Horizontal roll 22 ………… Group roll

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[Procedure amendment]

[Submission date] August 5, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taisuke Ito 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa Within Showa Electric Wire & Cable Co., Ltd. No. 1-1 No. 1 Showa Electric Cable Co., Ltd.

Claims (3)

[Claims] 1. A method for producing a thin-walled aluminum pipe of a predetermined size by extruding an aluminum pipe with a conform extruder to cool the aluminum pipe, and then subjecting the aluminum pipe to longitudinal molding. A method of manufacturing a thin-walled aluminum pipe, characterized in that a set roll composed of rolls and horizontal rolls is formed by a drive roll device arranged in multiple stages so that reduction between the set rolls is sequentially reduced. 2. A method for producing a thin-walled aluminum pipe of a predetermined size by extruding an aluminum pipe with a conform extruder to cool the aluminum pipe and then cooling the aluminum pipe A method for producing a thin-walled aluminum pipe, characterized in that a pair of rolls and horizontal rolls are molded by a driving roll device arranged in multiple stages such that the reduction between the pair of rolls is 2.5 to 4.5%. 3. The method for producing a thin-walled aluminum pipe according to claim 1, wherein the pair of rolls comprises a pair of drive vertical rolls for performing circular processing and a pair of non-drive horizontal rolls for performing oval processing. .