JP3511974B2 - Method for producing extruded profiles with uniform proof stress and cross-sectional shape - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an extruded profile in which the amount of springback generated during bending does not vary.

[0002]

2. Description of the Related Art In the extrusion method, a billet heated to a high temperature is loaded into a container and extruded through a die to produce an extruded material having a predetermined sectional shape. The amount of metal passing through the die is likely to vary in the plane of the die. For example, a large amount of metal tends to pass through a wide portion having a small flow resistance, and a metal passing amount tends to become relatively small at a narrow portion having a large flow resistance. The variation in the metal passing amount causes a defective shape such as bending in the extruded material extruded from the die. However, it is practically difficult to completely eliminate the variation in the amount of metal passing through, and bending also occurs due to the difference in the cooling rate of the extruded profile. Therefore, the extruded profile used for bending and the like is cooled to a temperature near room temperature after extrusion and then realigned to remove shape defects such as bending. The reshaped extruded profile is cut into product lengths, and after appropriate heat treatment,
It is used for bending.

[0003]

The extruded profile obtained is
Since the processing and heat history are different, it is inevitable that the yield strength will vary. When an extruded profile with a different proof stress, cross-section, etc. is bent, the amount of springback varies at each part of the extruded profile, and as a result it is difficult to obtain an extruded profile with a uniform shape. The heat-treatable alloy can eliminate variations in yield strength during heat treatment, but the non-heat-treatable alloy must eliminate variations in yield strength by work hardening.

As a method of working and hardening an extruded shape material,
Arrangement after extrusion and cooling is considered. In the straightening step, the extruded profile extruded from the extruder 1 onto the initial table 2 is passed through the runout table 3 and the cooling table 4.
(Fig. 1). When the extruded profile is cooled down to around room temperature on the cooling table 4, the extruded profile is transferred from the cooling table 4 to the straightening table 5, and both ends of the extruded profile are grasped by the head stock 6 and the tail stock 7 and stretched. At -8, pull in the straightening direction D and straighten.
Next, the extruded shape material is sent to the saw charge table 10 via the storage table 9, cut into a predetermined length by the cutting machine 11, and then conveyed to the next step.

The straightening removes the bending generated in the extruded profile due to the appearance of the metal from the die of the extruder 1 and the cooling conditions after the extrusion. However, if an extruded profile with a large local bending is tried to be realigned at a time with a large amount of pulling, the workability of the bent part becomes smaller than that of other parts, and the yield strength of the extruded profile in the longitudinal direction varies. Occur. Further, when the long extruded profile M is straightened, the stretched extruded profile M may be flexed and deformed by its own weight and come into contact with the straightening table 5 (FIG. 2). When the extruded profile M comes into contact with the straightening table 5, frictional resistance is generated, and a uniform tensile force in the longitudinal direction is not applied to the extruded profile M. This also causes variations in yield strength. Extruded profile M
Although the contact between the extruded profile M and the straightening table 5 is eliminated by shortening the length, when considering the production efficiency, within the length range of the tables 2 to 5 and 9 installed after the extruder 1. The length of the extruded profile is set as long as possible. Further, the straightening machine attached to the general extrusion equipment is set to have a large maximum straightening force in order to cope with various shapes.
With a straightening machine with a large maximum straightening force, it is difficult to keep the straightening amount constant and straighten an extruded profile made of a soft material having a small cross-sectional area.

[0006]

The present invention has been devised to solve such a problem, and by rearranging in two steps, a soft non-heat treated extruded profile having a small cross-sectional area. Even in this case, it is an object of the present invention to provide an extruded profile in which variations in proof stress and cross-sectional shape are eliminated. In order to achieve the object, the extruded profile manufacturing method of the present invention is such that after the extruded profile is cooled to near room temperature immediately after extrusion, the extruded profile is primary-rearranged at a constant realignment amount, and self-weighted during secondary realignment. It is characterized in that the extruded profile is cut to a length such that the extruded profile flexibly deformed by the above does not come into contact with the table, and the extruded profile after cutting is secondarily rearranged.

In the secondary straightening, the yield strength and cross-sectional shape of the extruded profile are made uniform by making the straightening amount constant, and a predetermined yield strength can be given to the extruded material by changing the straightening amount. The extruded profile that has been subjected to the secondary reordering is further drawn if necessary. The effects of primary and secondary realignment are
This is a non-heat-treatment type aluminum alloy having a proof stress after extrusion / cooling of 100 N / mm ² or less, which is remarkable in an extruded profile having a relatively small cross-sectional area. In this way, the extruded shape material in which the variations in the proof stress and the cross-sectional shape are eliminated has a constant springback amount generated during bending, and is thus formed into a bent product with good shape accuracy.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an extruded profile M sent from an extruder 1 is sent out onto a cooling table 4, and the extruded profile M is cooled to a temperature near room temperature, and then a head stock 6 and a tail stock 7 are provided. Then, both ends of the extruded profile M are gripped, and the extruded profile M is pulled in the alignment direction D by the stretcher 8 to perform primary alignment. In the primary straightening, the shape of the extruded profile M is made straight, and the initial values at the time of the secondary straightening are made uniform. Further, the primary straightening increases the proof stress of the extruded profile M, which facilitates subsequent handling.

The primary straightening is carried out by straightening the extruded profile M and then producing a proof stress value (for example, 50) which does not cause any trouble during handling.
N / mm ² or more) is set and 75% or less (desirably 60% or less) of the total straightening amount (= primary straightening amount + secondary straightening amount). When the amount of straightening due to primary straightening exceeds 75% of the total amount of straightening, extruded profile M due to secondary straightening
It becomes difficult to equalize the proof stress and the cross-sectional shape. In the primary straightening, the straightening speed is preferably 6 m / min or less. At a straightening speed of more than 6 m / min, both ends of the extruded profile M are likely to be constricted or broken, and a stretcher mark may be generated on the surface of the extruded profile M. Furthermore,
In the case of a long extruded profile M, it is difficult to apply a uniform tensile force over the entire length, so that the processed amount of the extruded profile M that has undergone primary reordering tends to vary, causing a variation in the yield strength value immediately after secondary realignment. Cheap.

The extruded profile M that has been subjected to primary reordering is transferred to the saw charge table 10 and then cut by the cutting machine 11. At this time, the length of the extruded profile M after cutting is set to a length that does not come into contact with the straightening table 5 due to bending due to its own weight.
Specifically, after increasing the proof stress of the extruded profile M by primary straightening,
At the time of secondary straightening, both ends of the extruded profile M are grasped and pulled in the straightening direction, and when the extruded profile M starts plastic deformation by the tension applied to the extruded profile M, the extruded profile M is aligned over the entire length. The length is set so that it does not come into contact with the straight table 5. For example, in the extruded profile M having a hollow cylindrical cross section, it is preferable to cut the extruded profile M into a length L (mm) or less calculated by the following equation. L = [σ × 44000 × [A + A × B × 0.15 / (A
-B)]] ^1/2 where A: outer diameter (mm) of extruded shape M B: inner diameter (mm) of extruded shape M σ: yield strength (N / mm ² ) Extrusion cut to a predetermined length The profile M is subjected to secondary straightening using a straightening machine similar to the primary straightening machine. In the secondary straightening, since the extruded profile M does not come into contact with the transport table 12 even if the extruded profile M bends and deforms under its own weight, the tensile force is evenly applied in the longitudinal direction of the extruded profile M, and the yield strength and cross-sectional shape are made uniform. To be done. The amount of secondary straightening is appropriately set according to the proof stress required for the extruded profile M.

In the secondary straightening, the straightening speed is preferably set to 4 m / min or less. At a straightening speed of more than 4 m / min, a local force is likely to be applied to a long extruded profile M, which causes variations in the proof stress of the secondary extruded profile M. High-speed pulling is also unsuitable for strict control of the pulling amount. Since the extruded profile M that has been realigned in multiple stages in this way has uniform yield strength and cross-sectional shape,
Variation in springback amount that occurs during bending can be suppressed. Therefore, the extruded profile can be bent with good shape accuracy.

When the extruded profile M that has been subjected to secondary reordering is further drawn, the yield strength is further improved. The drawing process has the effect of reducing variations in yield strength and making the cross-sectional shape of the extruded profile M uniform, and is particularly effective for the extruded profile M that requires high yield strength. That is, although the yield strength of the extruded profile M is improved by increasing the cold working degree by straightening, an excessively large straightening amount (pulling amount) tends to cause local deformation of the extruded profile M. There is a limit to the yield strength that can be imparted by straightening, and the uniformity of the cross-sectional shape tends to deteriorate. In such a case, the proof stress is improved and the cross-sectional shape is improved by the drawing process immediately after the secondary shaping.

[0013]

Example 1 Diameter 15 made of 3003 aluminum alloy
A 2 mm (6 inch) billet was loaded into the container of the extruder 1 and extruded into a hollow extruded profile having an outer diameter of 6 mm, a wall thickness of 1.5 mm and a total length of 40 m. After the extrusion, the extruded shape material M was cooled on the cooling table 4 to a temperature of 50 ° C. or lower, and transferred to the aligning table 5 equipped with the primary aligning machine. Hold both ends of the extruded profile M with the headstock 6 and the tailstock 7, and move the headstock 6 320 mm at a straightening speed of 3 m / min in the straightening direction D away from the fixed tailstock 7. The primary adjustment was done. The straightening ratio at this time is 320 mm ÷ 40 m × 100 = 0.
It was 8%. Cutting machine 11 for extruded profile M that has undergone primary reordering
It was cut into 3m length.

The cut extruded profile M is laterally held in the secondary straightening machine, and both ends of the extruded profile M are gripped by the head stock and the tail stock in the same manner as the primary straightening, and in the straightening direction away from the tail stock. The headstock was moved 30 mm at a straightening speed of 2 m / min. The straightening rate at this time is 30 mm ÷
It was 3 m × 100 = 1.0%. The extruded profile M was realigned in the same manner except that the realignment ratios of the primary realignment and the secondary realignment were changed. As shown in Table 1 in which the straightening ratio at this time is compared with the yield strength and outer diameter of the straightened extruded profile M, the yield strength and cross-sectional shape of the extruded profile M are changed by performing the straightening in multiple stages. It can be seen that they are made uniform. On the other hand, extruded profile M
In the case of re-arranging in the same manner as in the past, the proof stress on the rear side was higher than the front side in the extrusion direction of the extruded profile M, and the cross-section tended to be thinned.

Bending each reshaped extruded profile M R = 25 m
The bending workability was investigated by measuring the finished angle when bent 90 m at m. As can be seen in Table 1 showing the measurement results, the extruded profile material M realigned in multiple stages according to the present invention was formed with a good bending angle in each part in the longitudinal direction, and a bent product with good shape accuracy was obtained. .

[0016]

Example 2 The extruded profile M of Example 1 of the present invention obtained in Example 1 was drawn at a drawing rate of 15%. The drawn extruded shape material M was bent in the same manner as in Example 1, and the dimensions of each part of the bent product were measured. As can be seen from the measurement results in Table 1, the dimensional accuracy after bending was further improved by drawing.

[0017]

Comparative Example A 3003 aluminum alloy billet having a diameter of 152 mm (6 inches) was loaded into a container of the extruder 1 and extruded into a hollow extruded shape M having the same shape as in Example 1. After cooling the extruded profile M obtained on the cooling table 4 to a temperature of 50 ° C. or lower, both ends of the extruded profile M are gripped by the head stock 6 and the tail stock 7, and the alignment direction is set away from the tail stock 7. The extruded profile M was subjected to straightening in which the headstock 6 was moved to D by 720 mm at a straightening speed of 3 m / min. The straightening rate at this time is 720 mm ÷ 40
It was m × 100 = 1.8%.

The reshaped extruded profile M was cut into product lengths of 1 m. Table 1 shows the measurement results of the proof stress value and the cross-sectional shape of the extruded profile M cut into the product length. The bent product obtained by bending the extruded shape member M under the same conditions as in Example 1 had different finishing angles depending on variations in cross-sectional shape and proof stress, and had poor dimensional accuracy.

[0019]

[0020]

As described above, according to the present invention, the straightening for eliminating the shape defect such as the bending generated in the extruded profile produced by the extrusion molding is divided into two stages, and the primary straightening is performed. A certain amount of proof stress is given to the extruded profile, and the secondary molding straightens the proof stress and cross-sectional shape of the extruded profile. The extruded shape material having a uniform proof stress and uniform cross-sectional shape in this manner has no variation in the amount of springback generated during bending, and is thus formed into a bent product with good shape accuracy. Furthermore,
The extruded profile that has been drawn immediately after secondary shaping has a more uniform yield strength and cross-sectional shape, and thus is a bent product with better shape accuracy.

[Brief description of drawings]

[Fig. 1] Layout of extruder exit side

[Fig. 2] A state in which the extruded profile being adjusted is in contact with the adjustment table.

[Explanation of symbols]

1: Extruder 2: Initial table 3: Run-out table 4: Cooling table 5: Straightening table 6: Headstock 7: Tailstock 8: Stretcher 9: Storage table 10: Saw charge table 11: Cutting machine M: Extrusion type Material D: Straightening direction

─────────────────────────────────────────────────── ─── Continuation of front page (72) Motosei Hasegawa No. 20 Shimoda-cho, Sakai City, Osaka Prefecture Nippon Light Metal Co., Ltd. Osaka Plant (72) Masakazu Iwase No. 20 Shimoda-cho, Sakai City, Osaka Japan Light Metal Co., Ltd. Osaka Plant (56) References JP-A-7-124637 (JP, A) JP-A-5-5146 (JP, A) JP-A-62-83453 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B21C 35/03 B21C 1/00

Claims (4)

(57) [Claims] 1. Immediately after extruding, the extruded profile is cooled to a temperature near room temperature, then the extruded profile is primarily realigned with a constant straightening amount, and the extruded profile is flexibly deformed by its own weight so that the extruded profile does not come into contact with the table. A method for producing an extruded profile having a uniform yield strength and a uniform cross-sectional shape, which comprises cutting the material and then secondarily rearranging the extruded profile after cutting. 2. The manufacturing method according to claim 1, wherein the extruded shape material that has been subjected to secondary reordering is further drawn. 3. The yield strength after extrusion / cooling is 100 N / mm ^2.
The manufacturing method according to claim 1, wherein the following non-heat treated aluminum alloy extruded profile is used. 4. An extruded profile for bending, which is manufactured by the method according to claim 1.