JPS6340613A - Manufacture of hollow extruded shape having three dimensional shape changes - Google Patents

Abstract

PURPOSE:To obtain a hollow extruded shape having three dimensional shape changes and superior decorativeness by performing extrusion in a floating mandrel extrusion method by use of a layered hollow billet whose inner layer has a less deformation resistance than the outer layer. CONSTITUTION:An inner layer 2 of a layered hollow billet 1 is made of a material such as aluminum or aluminum alloys having a less deformation resistance than the outer layer 3. A ratio of the thickness of the layer 3 to that of the layer 2 is set to 1:2-10. A floating mandrel type die 5 is used as an extrusion die. In extrusion, the inner layer part of a hollow extruded shape 10 has a larger metal flow speed than the outer layer part and the shape 10 generates a bulge part 11 at the immediate back of a bearing part 5a because the inner layer 2 of the billet 1 has a less deformation resistance than the outer layer 3. Then, the shape 10 is extruded at a stroke to form bulge parts 10a having a larger diameter, so that the succeeding part forms a relatively small diameter part 10b. Repeated extrusions arrange the large diameter parts 10a and small diameter parts 10b alternately.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a hollow extruded material having a three-dimensional shape change, and more particularly, to an extruded material used as a structural material, in which the longitudinal direction of the extruded material is The present invention relates to a hollow extruded material mainly made of metal such as aluminum or aluminum alloy, the cross-sectional shape of which changes repeatedly in regular or irregular cycles.

Conventional technology and problems The production of hollow extrusions of aluminum and other metals
A female mold (21) that defines the external shape of the extruded material as shown in the figure;
The die (
20), the metal flow is controlled in the annular gap (23) oriented in the extrusion direction between the male and female molds (21) and (22), and an extruded material (24) with a predetermined cross-sectional shape is continuously formed. is common.

In this original extrusion molding method, the bearing parts (21a) (22a) of the female mold (21) and the male mold (22) are
) determines the final product shape of the extruded material (24), and while this is advantageous in obtaining a regular material with a uniform cross-sectional shape, on the other hand, it is natural when using a specific die. However, it is only possible to manufacture products with a constant shape. For this reason, when producing highly decorative pipes with a longitudinal cross-sectional shape for use as carport posts, fence posts, furniture legs, etc., the hollow extrusions are further processed by swaging. Secondary processing such as bulge processing and beading processing has been performed to impart three-dimensional shape changes. Of course, when such a method is used, it requires a two-step processing process, resulting in an unavoidable problem of high costs.

Based on the background of the prior art as described above, the present invention continuously manufactures hollow extruded materials whose cross-sectional shape, particularly the outer diameter, changes in the length direction at regular or irregular intervals through an extrusion operation. This paper presents a method for

Means for solving the problem of interstices This invention aims to achieve the above-mentioned purpose by using a hollow billet in which materials with different deformation resistances are layered on the inside and outside, and when this is extruded by a floating mandrel extrusion method, the extrusion This work was completed by discovering scales that change the external shape of an extruded material in three dimensions due to uneven metal flow between the inner and outer layers of the material.

That is, the present invention uses a laminated hollow billet clad with an outer layer and an inner layer made of a material having a relatively lower deformation resistance than the outer layer, and performs an extrusion operation by a floating mandrel extrusion method to produce an extruded material. The large-diameter part and the small-diameter part are regularly repeated in the longitudinal direction of the extruded material by periodically repeating the process of filling the relief part of the mandrel die with the bulge formed on the outer periphery of the extruded material and then discharging it from the die all at once. The gist of the present invention is a method for manufacturing a hollow extruded material having a three-dimensional shape change.

This will be further explained in detail based on the attached drawings as follows.

In this invention, the billet to be subjected to extrusion is as follows:
As shown in Figure 2, the inner layers (2) have mutually different deformation resistances.
A layered hollow billet (1) is used, which is clad with an outer layer (3). Moreover, the inner layer (2) is the outer layer (3).
) shall be made of a material with lower deformation resistance. The billet (1) is most commonly made of aluminum or its alloys, for example the inner layer (2) has a purity of 9.
A 9.99% high purity aluminum alloy is used for the outer layer (3), and an AΩ-Mg-8i based 6063 aluminum alloy is used. The relative thickness ratio of the inner and outer layers (2) and (3) can be appropriately set in relation to the desired shape change of the extruded material, but the thickness of the outer layer (3) relative to the thickness of the inner layer (2) It is best to set the ratio to about 1=2 to 10, especially 1:5.
It is preferable to set it to a certain degree.

For extrusion, it is especially necessary to use a floating mandrel type die (5) as shown in Figure 1, and the outer diameter of the mandrel bar (6) is larger than the inner diameter of the hollow part of the hollow billet (1). Needless to say, the bearing part (5a) of the die (5) should be kept small.
) should be smaller than the outer diameter of the inner layer (2) of the hollow billet (1), and the inner diameter of the relief part (5b) should be the same as the diameter of the large diameter part to be applied to the extruded material (10). Consider the relationship and set the diameter accordingly.

In FIG. 2, (8) represents a stem, and (9) represents a dummy block.

During extrusion molding, the layered billet (1) is loaded into an extruder container (7), and extrusion is started after performing necessary upsetting and viasing operations. The extrusion conditions here are based on the usual floating mandrel extrusion method, but the extrusion ram speed is preferably set slightly faster than in the usual case.

When extrusion is performed as described above, the inner layer (2) of the hollow billet (1) has lower deformation resistance than the outer layer (3), so
The metal flow rate is faster in the inner layer of the hollow extruded material (10) than in the outer layer.

Due to this influence, the extruded material (10) swells when it exits the bearing part (5a) in the die mouth. Then, this bulging portion (11) becomes clogged with the relief portion (5b) on the exit side of the die opening, but as extrusion continues, the bulge that once clogged the relief portion (5b) becomes clogged. The milled portion (11) is then discharged from the die opening to form a large diameter portion (10a) with an increased outer diameter in the extruded material (10). Therefore, the part that is subsequently extruded has a relatively small outer diameter within the range regulated by the bearing part (5a), and the extruded material (1
A small diameter portion (10b) is formed in 0). Therefore, due to the above-mentioned periodic repetition, the extruded material (10) has a large diameter part (10a) and a small diameter part (lob) regularly as shown in FIG. 3, or irregularly depending on the extrusion conditions. The desired hollow extruded material (10) with a three-dimensional change in cross-sectional shape in the length direction is obtained.

Effects of the Invention According to the present invention, although the extrusion method is adopted as described above, the inner layer of the extruded material is This causes a change in the extrusion metal flow rate between the outer layer and the outer layer.
As a result, the extruded material has bulge-like large-diameter portions and trough-like small-diameter portions in an alternating arrangement. Therefore, a highly decorative hollow extruded material with a three-dimensional shape change that resembles that of bamboo can be produced with extremely high efficiency. This has the effect of significantly reducing product costs compared to cases where ribs are exposed or the like.

Example inner layer (2) is made of an aluminum alloy with a purity of 99.99%,
A layered hollow billet (1) was prepared in which the outer layer (3) was made of 6063 aluminum alloy and both layers were integrally clad. The dimensions of the billet (1) are: Hollow inner diameter: 40mm5
Outer diameter of inner layer (2): 60 mm, outer diameter of outer layer (3): 16
0mm.

Length: 300mm.

On the other hand, the extrusion metal was of a floating mandrel type, and the outer diameter of the mandrel bar (6) was set to 30 mm, the diameter of the bearing part (5a) of the die (5) was set to 36 mm, and the diameter of the relief part (5b) was set to 47 mm. .

The above hollow billet (1) was preheated and loaded into the extruder container (7), and extrusion processing was performed under the following extrusion conditions: billet temperature: 450''C1 die temperature: 400℃, ram speed: 1゜5 mm/sec. Ta.

However, as shown in FIG.
A hollow extruded material (10) having a pseudo-bamboo-like appearance and having a three-dimensional shape change in which Oa) and small-diameter portions (10b) were arranged in an alternating arrangement through gently sloped portions was obtained. Here, the extruded material (10) has an outer diameter of the large diameter portion (10a): 47 mm,
Outer diameter of small diameter part (fob): 36mm, large diameter part (10a
) pitch: varied between 200 and 300 mIn, and the inner diameter of the hollow part was 30 mIn.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of the die section showing the extrusion molding state according to the present invention, FIG. 2 is a perspective view of a stratified hollow billet used in the present invention, FIG. 3 is a crushed side view of the extruded material as a product, and FIG. FIG. 4 is a longitudinal sectional view of the die section showing the state of extrusion molding according to the conventional method. (1)...Stratified hollow billet, (2)...Inner layer,
(3)...Outer layer, (5)...Dice, (6)...
Mandrel bar 1 (7)...container, (5a)...
・Bearing part, (5b)...Relief part, (10)
... Extruded material, (10a) ... Large diameter part, (10b)
...small diameter part. that's all

Claims (3)

[Claims] (1) Using a layered hollow billet clad with an outer layer and an inner layer made of a material with relatively lower deformation resistance than the outer layer, the outer periphery of the extruded material is extruded by the floating mandrel extrusion method. By periodically repeating the process of filling the relief part of a mandrel die with the bulge that occurs in the extruded material and then discharging it from the die all at once, large-diameter parts and small-diameter parts are regularly and repeatedly formed in the longitudinal direction of the extruded material. A method for producing a hollow extruded material having three-dimensional shape change, characterized by: (2) The method for producing a hollow extruded material having a three-dimensional shape change according to claim 1, wherein the ratio of the thickness of the outer layer to the thickness of the inner layer of the laminated hollow billet is in the range of 1:2 to 10. (3) A method for producing a hollow extruded material having a three-dimensional shape change according to claim 1 or 2, wherein the layered hollow billet is made of aluminum or an aluminum alloy.