JPH08117839A - Extrusion molding method - Google Patents

Abstract

PURPOSE: To prevent the intrusion of the shell and air at the rear end of a billet by temporarily stopping the container before bringing the container into contact with a die and sealing an extrusion stem side with a sealing block and removing the air, then executing upsetting while cooling a dummy block. CONSTITUTION: The container 1 is temporarily stopped by allowing a spacing 6 to remain between the container and the die 3. The extrusion stem 6 side is sealed by the sealing block. The air is removed from the spacing between the container 1 and the die 5. Upsetting is executed while the die block 2 mounted at the front end of the extrusion stem 6 is cooled. Since the air is removed from the spacing, the air is surely removed. The rear end of the billet 4 is cooled by the dummy block 2 and, therefore, the slip with each other does not arise any more and the intrusion of the shell to the rear end of the billet 4 is prevented. Extrusion molding is executed by pressing the container 1 and the die 5 to each other just prior to completion of the upsetting. Since the air in the container 1 is completely removed, the intrusion of the air is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when extrusion molding an aluminum alloy or the like by an extrusion press, deaerates air between the container and the billet before the billet is extruded from inside the container through a die. , The billet can be extruded effectively and without air,
The present invention relates to an extrusion molding method in which, at the time of extrusion molding, the skin at the rear end of the billet in the container and the air adhering to the skin are prevented from being entrained inside the rear end of the billet.

[0002]

2. Description of the Related Art After a billet having a diameter slightly smaller than the inner diameter of the container is put into the container, the billet is pressed against the die with the stem at the rear in the container, so-called upsetting, the billet is crushed and the air between the container and the billet is crushed. Is compressed. In order to release the compressed air, the stem and the container are slightly retracted, the compressed air is discharged from the gap between the die and the container, and the container and the stem are advanced again to start extrusion. The degassing process for removing the compressed air in this way is called a burp cycle, but this process causes a waste of time in the extrusion cycle.

According to this method, when a container is pressed against a die by degassing in a burp cycle, air remains at atmospheric pressure in a thin state of about one skin between the inner surface of the container and the outer surface of the billet. And sufficient degassing has not been performed. Further, aluminum dust often adheres to the container liner end surface and the die end surface. If it adheres in a uniform film form, there should be no intrusion of air when it is sealed, but in general, dust adheres unevenly. For this reason, even if the inside of the container was degassed, even if air entered again and a burp cycle was carried out by the time the upsetting of the billet was completed, the blister was generated.

That is, in order to sufficiently deaerate the inside of the container before starting the extrusion, for example, as described in Japanese Patent Application No. 5-60621 and Japanese Patent Application No. 5-190340, the container is Before contacting the die, the container is temporarily stopped by the temporary stop mechanism, and the die outer surface is sealed by the front part of the die ring seal attached to the front of the container, and the end surface of the die contacts the end surface of the die side of the container. It has been considered that the air accumulated in the container is vacuum-sucked through the deaeration hole of the die ring seal from the gap created so as not to allow it.

However, even with this, a sufficient effect was not always obtained. That is, in the device in such a case, as shown in FIG.
As shown in 0 (a), container 1 and dami block 2
Since there is a gap d of, for example, about 0.1 to 0.3 mm, vacuum suction is performed from the die ring seal 3 attached to the front part of the container 1 and the space S between the container 1 and the billet 4 is created. Even if an attempt is made to degas certain air, outside air enters the space S through the gap d between the rear part of the container 1 and the damy block 2 and cannot be degassed, or the ultimate vacuum becomes close. In the figure, 5 is a die and 6 is an extrusion stem.

Therefore, as shown in FIG. 10 (b), by slightly upsetting the billet 4, the rear portion of the billet 4 from the damy block 2 side within a certain dimension h, for example, 50 to 100 mm. The outer peripheral surface is brought into close contact with the inner peripheral surface of the container 1, and after completely sealing, deaeration is started.

[0007]

However, at this time, the area h of the rear portion of the billet 4 is upset in the atmospheric state, and at the same time, the air on the surface is caught in the billet 4. Then, it becomes a blister of an extruded profile extruded from the die 5.

On the other hand, at the time of upsetting after this state, slippage occurs between the relatively hot Damii block and the billet, and as a result, the outer skin of the rear end of the billet 4 becomes the billet 4.
Get caught in the inside of. This entrainment is shown in FIG.
Occurs as shown by the arrow in FIG. 2 and starts when the rear end of the billet 4 contacts the inner surface of the container 1 at the time of upsetting, and the space S is completely eliminated until the filling is completed and the upset is completed. Therefore, the range of the seal portion indicated by h in FIG. 10B enters the inside of the billet 4.

Therefore, in the present invention, as a solution to these problems, as in Japanese Utility Model Laid-Open No. 3-81214 and Japanese Utility Model Laid-Open No. 4-197514, a cooling device for a fixed damy block is provided between the container and the extrusion stem. Is provided so that the cooling medium is sprayed or abuts against the extrusion action surface of the fixed damy block. However, the extrusion action surface of the fixed damy block is exposed during the idle time (about 15 to 25 seconds) of the extrusion press. About 450 to 250
There was a problem that it was difficult to lower the temperature until the temperature fell below ℃.

Further, some attempts have been made that the internal temperature of the fixed damy block itself (fixed damy block of internal cooling type) may cause a large drop due to the temperature drop of the extrusion working surface. On the other hand, in the case of metal touch or metal seal, the cooling medium communicating from the inside of the extrusion stem leaks between the core block and the outer ring that make up the Damii block, which leads to deterioration of operation and work environment.
In particular, at the time of extrusion, there is a problem that the leaked cooling medium scatters and drops inside the container.

The present invention has been made in view of the above-mentioned problems, and at the time of extrusion molding, the air between the container and the billet is degassed to the outside of the container, and at the time of upsetting, the outer shell of the billet rear end is introduced into the billet. An object of the present invention is to provide an extrusion molding method in which entanglement is prevented and a good quality extruded profile without blisters is obtained.

[0012]

Therefore, in the present invention, when the air between the extrusion container and the billet is degassed before the extrusion of the billet is started, the container is temporarily stopped before it is brought into contact with the die. While the container is temporarily stopped by the mechanism, at the end surface of the extrusion stem side of the extrusion container, while the seal block is closed to the extrusion stem, the inside of the die block and the die side of the container and the die side of the container are cooled while the billet is being pressed. Degas the air accumulated in the container and in the discard recess created by the shear blade during pre-extrusion from the gap created by not contacting the end faces, and start contacting the container with the die immediately before the completion of upset. did.

[0013]

When the billet in the container is pushed by the stem behind the billet and the billet is pressed against the die, the billet is crushed and the air between the container and the billet is compressed. This compressed air must be sucked and degassed from both sides of the container before the billet is pushed out of the die. In addition, the billet inside the container must be pushed by the stem behind the billet, and suction and degassing must be performed from both sides of the container just before pressing the billet tip against the die. In the present invention, since the air in the container is forcibly vacuum-sucked on the die side of the billet before the billet is compressed by the stem, a step for soaking the compressed air after the billet is compressed by the stem, so-called degassing The process can be omitted.

When sucking air from the die side of the container, first, it is arranged on the end face of the container on the stem side and sealed with a seal block which can be opened and closed in the axial direction of the container, and then attached to the tip of the container. Since the seal ring that is engaged with the outer ring and is movable in the axial direction and the end surface of the die ring on the container side are sealed, air is sucked through the minute gap between the die and the container. The air between billets can be completely degassed,
A blister-free extruded product is obtained.

On the other hand, at the time of upsetting, the damii block cooled from the inside is used for upsetting. Therefore, sliding between the billet rear end inner surface of the container rear end and the front end surface of the dami block is reduced. Therefore, at the time of upsetting, air is prevented from being entrained in the outer skin of the billet rear end portion and the portion thereof, and a good-quality extruded shape material in which blisters are prevented can be easily obtained.

Further, by sealing the front part between the core block and the outer ring with the seal material, it is possible to prevent the cooling medium from leaking from the damy block at the time of upsetting, and the life of the container is extended.

The present invention will be described below in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment for carrying out the method of the present invention, FIG. 2 is an enlarged sectional view of the extruding stem side of FIG. 1, and FIG. 3 is a front view seen from DD of FIG. 4 is shown in FIG.
5 is a front view seen from AA of FIG. 5, FIG. 5 is an enlarged cross-sectional view of a main part of a suction unit that sucks air through a minute gap between a die and a container, FIG. 6 is a front view seen from CC of FIG. 1, and FIG. Explanatory drawing of vacuum suction from between the container and the die after pressing the tip of the billet to the die, FIG. 8 is explanatory drawing of vacuum suction from between the container and the die immediately before pressing the tip of the billet to the die, and FIG. 9 is inside the container FIG. 10 is a conceptual diagram showing how the billet crushed by crushing is crushed, and FIG.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to one embodiment shown in FIGS.
The present invention will be described in detail. In FIG. 1, a vacuum suction device 30 as shown in FIG. 4 is provided on the die 5 side of the container 1 including the container liner 1a and the container tire 1b. An outer ring 15 concentric with the container 1 is fixed to the end surface of the container tire 1b on the die 5 side by bolts. In addition, the outer ring 15
A seal ring 16 is provided on the inner peripheral surface side of which is engaged in a step-like manner so that it can move forward and backward and cannot be disengaged.

A part of the seal ring 16 has a structure having a projecting portion 16a projecting toward the center, and the container 1
When the container 1 is temporarily stopped by a temporary stop mechanism leaving a gap of, for example, 2 to 3 mm between the die 5 and the die 5, the seal ring 16 is attached to the end surface of the die ring 5a on the container 1 side.
Of the spring 17 (in this embodiment, eight springs 17 are evenly spaced between the container tire 1b and the seal ring 16).
Are abutted against each other in the pushing direction (face seal) to make the clearance zero. Reference symbol S is a gap between the inner peripheral surface of the container 1 and the outer peripheral surface of the billet 4, and is also a deaeration space.

A deaeration hole 18 is provided above the seal ring 16.
There are two (in this embodiment), and from there are connected to a vacuum tank 11 and a vacuum pump 12 via a pipe 9 and an electromagnetic switching valve 10. 13 is a motor, 19 is an outer ring 1
5 is a heat-resistant sealing material that prevents air from entering between the seal ring 16 and the seal ring 16, and 20 is the outer ring 15 and the container tire 1.
Metal hollow ring to prevent air from entering between b, 21
Is a replaceable seal plate that prevents direct abrasion and air intrusion of the protrusion 16a of the seal ring 16 by repeated contact with the die ring 5a. Also, 4 is a billet, 6
Reference numeral 2 denotes an extruding stem, 2 is a fixed damy block which is attached to the tip of the extruding stem 6 and which is in close contact with the inner surface of the container 1 and pushes the rear end surface of the billet 4.

The container 1 is attached to a piston rod 25 of a container cylinder 24 attached to the end platen 23. Reference numeral 28 is a piston, and 29 is a cylinder tube forming a cylinder body. Container cylinder 2
The portion B on the piston head side of No. 4 is composed of a movement stopper block 26, a head block 27 that also serves as a stopper, and the like, and the piston 28 can be rapidly stopped at the maximum distance of the movement range of the movement stopper block 26. . When the piston 28 is temporarily stopped just before the rear end, the container 1 is stopped just before it hits the die 5. 37 is a plug on the rear part.

A hollow rod 31 having a plurality of communication holes for oil passage arranged in a zigzag pattern in the axial direction is integrally attached to the rear shaft core portion of the piston 28, which is the head side, by screws or the like. When 28 is retracted, the hollow rod 31 enters into the hole on the front end side of the movement stopper block 26.

The structure on the side of the extrusion stem 6 is as shown in FIG. In FIG. 2, 1 is a container, 6 is a tubular extrusion stem, 2 is fixedly provided on the front surface of the extrusion stem 6,
Further, it is a fixed type damy block slidably provided in the container 1. The rear end of the extrusion stem 6 is shown in FIG.
As shown in, the stem holder 53 and the pressure ring 5
It is fixed to the main crosshead 55 via the No. 4.

A tubular dami boss 56 is attached to the front face of the extruding stem 6 by pressing the rear end face thereof. The tip of a connection rod 57 having a circular outer cross section is screwed to the rear half of the dami boss 56. It is installed by installation. The rear end portion of the connection rod 57 is a large diameter portion 57a as shown in FIG. 1, and is engaged and fixed with a tapered surface in the hole at the rear end portion of the extrusion stem 6. In the connection rod 57, two parallel holes 57b and 57c are provided so as to penetrate in the axial direction.
A water supply pipe 58 and a drain pipe 59 are provided in b and 57c. The tips of the water supply pipe 58 and the drainage pipe 59 are firmly mounted in the holes 57b and 57c by interference fit, and the rear ends thereof extend into the pressure ring 54.

The end of the water supply pipe 58 has a pressure ring 5
A cooling medium supply device 62 is connected via a passage 60 formed by a pipe in 4 and an opening / closing valve 61. The end of the drainage pipe 59 is connected to the drainage port 64 through a pipe passage 63 in the pressure ring 54. A small gap is provided between the inner peripheral surface of the extrusion stem 6 and the outer peripheral surface of the connection rod 57 in order to keep the core of the connection rod 57 in a flexible state. In addition, a slight gap is provided between the inner peripheral surfaces of the holes 57b and 57c and the outer peripheral surfaces of the water supply pipe 58 and the drain pipe 59 so that the connection rod 57 is not directly cooled.

In this case, since the water supply pipe 58 and the drain pipe 59 are provided in the connection rod 57 with a gap therebetween, the connection rod 57 is not directly cooled, and therefore, the temperature difference between the extrusion stem 6 and the connection rod 57 is reduced. The flexibility of the core of the dami block 2 is not impaired. Although the hole 57b in the connection rod 57 is provided so as to penetrate therethrough, the front end of the hole 57c is closed by the plug 65, and the opening 6 in the outer peripheral direction is formed.
It communicates with 6. 67 is an extrusion stem 6 and a dami boss 5
6 is a heat resistant packing, and 68 is a heat resistant packing between the holes 57b and 57c and the water supply pipe 58 and the drain pipe 59.

A tubular connection bolt 69 is arranged in the front half of the dami boss 56, and a core block 70 is fixed to the front side of the connection bolt 69 by screw mounting. A ring-shaped outer ring 71 is fixed to the front side of the dami boss 56 by screw mounting. The outer peripheral surface of the core block 70 is in contact with the inner peripheral surface of the outer ring 71, but a gap is provided between the rear end surface of the core block 70 and the front end surface of the dami boss 56, and the core block 70 is extruded during extrusion. Even if 70 is pushed a little backward, the rear end surface of the core block 70 is dami boss 56.
It does not hit the front end face of the.

The core block 70, the outer ring 71, the dami boss 56 and the like constitute the dami block 2 as one body. Therefore, the outer peripheral surface of the outer ring 71 on the front end side is sized to substantially contact the outer peripheral surface of the container 1. Further, the outer peripheral portion of the front end of the core block 70 has a tapered surface portion 70a that widens to the front side, and the outer ring 71
The taper surface portion of the inner peripheral portion of the front end can be closely attached.

The shaft core hole of the connection bolt 69 serves as a passage 72 for the cooling water, and the rear half of the outer peripheral surface of the core block 70, that is, the outer ring 71 and the inner and outer diameters of the core block 70. A ring-shaped pool groove 73 for cooling is provided in the fitting portion, and the tip end portion of the passage 72 extends to the vicinity of the outer surface 85 of the core block 70.

As shown in FIG. 3, a plurality of radial cooling holes 74 (8 in this embodiment) extending radially from the tip of the passage 72 to the outer ring 71 are provided.

The rear portion of the pool groove 73 is provided with a passage 75 provided in the core block 70 and the dami boss 56, and one end of the passage 75 has a connection rod 5
7 and the other end is connected to the radial cooling holes 74. The passage 75 is connected to the front portion and the rear portion of the pool groove 73 on the way, and the plugs 79, 80, 81, 82 are provided at the locations shown in FIG. 2 so that the cooling water in the reciprocating path always passes through the pool groove 73. Is installed. 76 is a plug, and 77 and 78 are packings such as heat resistant O-rings.

Next, as shown in FIG. 7, a shielding device 60 for blocking the air that enters the container 1 from the extrusion stem 6 side is arranged on the end surface of the container 1 on the extrusion stem 6 side. On the end surface of the container 1 on the extrusion stem 6 side, a split seal block 40 is provided so as to be openable and closable in the direction perpendicular to the axial direction of the container 1, and when the seal block 40 is closed, the seal block 40 is provided on the inner peripheral surface of the seal block 40. The seal packing 41 is provided so that it can be brought into close contact with the outer peripheral surface of the extrusion stem 6.

Reference numeral 42 is a guide plate, and both blocks of the seal block 40 can be opened and closed by a cylinder 43. 41 and 44 are seal packings.
Reference numeral 47 is a heat insulating material so that a part of heat generated by heating the container 1 is prevented from being transferred to the shielding device 60 by heat conduction. The guide plate 42 described above is provided with a cover plate 48 provided on the upper surface of the heat insulating material 47. It is arranged through.

Next, the operation of the extrusion molding apparatus will be described.

First, before extrusion molding of the billet 4, the electromagnetic switching valve 10 is in a demagnetized state, and the vacuum pump 12 is driven to keep the vacuum tank 11 in a vacuum state of, for example, 0 to 10 Torr.

Next, pressure oil is supplied to the rod side of the container cylinder 24, the piston 28 is moved leftward, and the container 1 separated from the die 5 is advanced. This time,
While the distal end of the hollow rod 31 attached to the piston 28 moves to the distal end of the stopper block 26, the retreating speed of the piston 28 is relatively high. Eventually,
The hollow rod 31 begins to enter the hole of the stopper block 26, and the piston 28 decelerates.

In this state, the piston 28 continues to retract,
The tip surface portion of the piston 28 contacts the tip portion of the stopper block 26. At this time, the piston 28 completes stopping at an intermediate position due to the action of the stopper block 26. Then, due to the action of the stopper block 26, the accuracy of the stop position in the middle of the stroke is sufficiently ensured. At this time, the protrusion 16a of the seal ring 16 contacts the die ring 5a, and the gap 7 between the container 1 and the die 5 is, for example, 2 to 3 mm. The state at this time is shown in FIG.

When this operation is completed, a billet loader (not shown) is raised while the billet 4 is still placed, and when the extrusion stem 6 is advanced, the billet 4 is pushed into the container 1. At this time, there is air in the deaeration space S between the container 1 and the billet 4.

The vacuum pump 11 is already in the vacuum tank 11.
Therefore, for example, it is in a vacuum state of 0 to 10 Torr. First, as the extrusion stem 6 advances, the billet 4 is moved to the container 1
When pushed in, the tip enlarged diameter portion 83 of the extruding stem 6 passes through the seal block 40 and the cylinder 43 of the shielding device 60 arranged on the extruding stem 6 side of the container 1 is operated. Seal block 40 divided in two
To close the space between the extrusion stem 14 and the container 1 (FIG. 6).

When the electromagnetic switching valve 9 is excited in this state, vacuum suction of the residual air in the container 1 is started by the vacuum tank 11. Then, the extrusion stem 6 is further advanced, and immediately before the tip of the billet 4 hits the die 5, the advancement of the extrusion stem 6 is temporarily stopped, and when the degree of vacuum in the container 1 reaches a target value, the extrusion stem 6 is again moved by the side cylinder. When the pressure oil in the side cylinder reaches a predetermined pressure, the main cylinder (not shown) is switched to complete the upset.

Here, the case where the extrusion stem 6 advances to start upset will be described. However, before starting the upset, the cooling medium supply device 62 is actuated to introduce a cooling medium such as cooling water into the radial cooling holes 74 and the pool groove 73 to cool the damii block 2 from the inside. At this time, cooling water enters from the rear of the extrusion stem 6,
The passage 72, the radial cooling holes 74, the passage 7 pass through the water supply pipe 58 in the connection rod 57 in the extrusion stem 6.
5, the water enters the pool groove 73, passes through the passage 75 and the drain pipe 59, and is discharged from the rear of the extrusion stem 6.

In the present invention, the radial cooling holes 7 are used.
4 are provided radially in the vicinity of the outer surface 85 of the core block 70 from the center to the outside, so that the temperature of the outer surface 85 of the damii block 2 at the time of upset is set to 2 by cooling water flow.
It can be cooled to 00-230 ° C. Further, since the pool type cooling groove is provided in the outer peripheral portion of the core block 70, the passage volume can be made relatively large, and as a result, the heat inside the container 1 is transferred to the outer peripheral surface of the outer ring 71. This is suppressed, and cooling of the inside of the core block 70 is promoted. Therefore, the temperature of the core block 70 is lowered, which is advantageous in terms of strength. However, in this example, the idle time was 15 seconds.

The radial cooling holes 74 are also used for the pool groove 7
Similar to 3, the cooling water is not easily vaporized, and the structure is simple.

Therefore, when the upset is started in such a state, the rear end of the billet 4 in contact with the damy block 2 is cooled. At the same time when the upset is started, the vacuum suction device 30 such as the vacuum pump 12 is actuated to suck the air in the container 1 through the gap 7 between the container 1 and the die 5 to make the inside of the container 1 sufficiently vacuum.

At the time of performing the upset, since the rear end of the billet 4 is cooled and the fluidity is considerably deteriorated, the degree of friction between the front end face of the damii block 2 is increased and the billet 4 It is possible to prevent the outer skin of the end portion from adhering and the inclusion of impurities and air inside. In this way, the air that causes blisters is prevented by cooling the damii block 2 to prevent the trailing end skin of the billet 4 and the air from being entrained inside and degassing the surface of the billet 4 on the front die 5 side. Can be fully removed.

Particularly, in this embodiment, various experiments were carried out, and if the front end surface of the damy block 2 was 250 ° C. or lower, the billet 4
The fluidity on the rear end side is deteriorated, and the billet 4 is prevented from being caught in the outer skin of the rear end portion, and the formation of blisters in the extruded product profile can be prevented.

During the upset, the extrusion stem 6 continues to move forward without a break, the billet 4 is crushed, and when the end surface of the billet 4 on the die 5 side begins to deform, the container 1 is advanced to the die 5 side and The gap 7 of the die 5 becomes zero. The reduction of the gap 7 is performed by the backward movement of the movement stopper block 26.

Even in the process of decreasing the clearance 7, the deaeration hole 8 of the die ring seal 3 is evacuated, and the deaeration space immediately before the billet 4 is completely upset on the inner surface of the container 1. The gap S part which is also 0-3
It is evacuated to 0 Torr. When the billet 4 starts to be extruded from the die 5, the electromagnetic switching valve 10 is closed and the vacuum drawing from the die 5 side is stopped. However, the evacuation may be continued as it is.

Here, the crushed state is shown in FIG. In these figures, the degassing space S between the container 1 and the billet 14 is the extrusion stem 6 and the billet 4 is S in the die direction.
If the pressure is increased from 1 to S3 sequentially, this degassing space S
It can be seen from Fig. 9 that is pushed into the die side.

Even after the suction and degassing are started, the extrusion stem 6 continues to move forward and crushes the billet 4. Then, the billet 4 is filled in the container 1 to complete the upset. Next, the extrusion is continued, and the product is extruded from the die 5. In this embodiment, the temporary stop mechanism is provided in the container cylinder 24 to temporarily stop the container 1. However, the present invention is not limited to this, and the container 1 may be temporarily stopped by another method.

Furthermore, in the present embodiment, even when the fixed damy block 2 having the structure of the present invention is used, it is further effective to provide a cooling device separately and inject cooling water to the outer surface 85 (extrusion surface) of the damy block 2. If there is a jet cooling for about 3 seconds within the idle time, 160-18
It is possible to reduce the temperature to 0 ° C.

Further, in the present embodiment, even when the fixed type Damii block 2 having the structure of the present invention is used, the billet 4 is placed on the billet loader (not shown) and positioned between the container 1 and the extrusion stem 6. In this state, the cooling water is sprayed using a cooling device and sprayed on the rear end of the billet 4 for about 3 to 5 seconds.
The temperature drops to 0 to 300 ° C.

After that, when the extruding stem 6 is advanced to load the billet 4 into the container 1, a synergistic effect with the cooling of the outer surface 85 by the cooling device provided in the extruding stem 6 of the present invention causes a synergistic effect of the billet 4. Since the rear end portion is cooled more and the fluidity of the rear end portion of the billet 4 can be suppressed, it is possible to prevent the rear end portion of the billet 4 from being caught in the outer skin.

[0055]

As is apparent from the above description, in the present invention, when the air between the extrusion container and the billet is degassed before starting the extrusion of the billet, the container is brought into contact with the die. Before stopping, the container is temporarily stopped by the temporary stop mechanism, and at the end face on the extrusion stem side of the extrusion container, the seal block is closed against the extrusion stem during billet pressing while internally cooling the die end face. The air accumulated inside the container and in the discard recess created by the shear blade during pre-extrusion is degassed from the gap created by avoiding contact with the die side end surface of the container, and the container is contacted with the die immediately before the upset is completed. By starting it, a seal is created between the container and extrusion stem and between the container and die. The air in the container can be reliably easily degassed. Therefore, an extruded product without air entrainment can be easily obtained. Further, even after the predetermined vacuum degree is reached and the container is sealed, the deaeration action from the die side continues until immediately after the start of extrusion, so that there is no possibility that air will flow backward from the sealing surface again and enter.

Further, the damey block in contact with the billet can be upset in a state where it is cooled by the radial cooling holes having a large cooling ability close to the outer surface (extrusion surface). That is, the plurality of radial cooling holes has a relatively large volume, cooling water is less likely to be vaporized, and effective cooling is obtained. As a result, at the time of upset, the rear end of the billet can be appropriately cooled so as to prevent slippage on the Damii block, and the skin of the billet rear end and the air adhering to the skin inside the rear end of the billet can be rolled up. It is possible to prevent the occurrence of blisters in the extruded profile.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of an apparatus for carrying out the method of the present invention.

FIG. 2 is an enlarged sectional view of the extrusion stem side of FIG.

FIG. 3 is a front view seen from D to D in FIG.

FIG. 4 is a front view seen from AA of FIG.

FIG. 5 is an enlarged cross-sectional view of a main part of a suction unit that sucks air through a minute gap between a die and a container.

FIG. 6 is a front view seen from CC of FIG.

FIG. 7 is an explanatory diagram of vacuum suction from between the container and the die after pressing the tip of the billet against the die.

FIG. 8 is an explanatory diagram of performing vacuum suction from between the container and the die immediately before pressing the tip of the billet against the die.

FIG. 9 is a schematic view showing how to collapse a billet pressurized in a container.

FIG. 10 is an explanatory diagram showing, in chronological order, an operation state at the time of upset in the conventional method.

[Explanation of symbols]

 1 Container 2 Damii Block 3 Die Ring Seal 4 Billet 5 Die 6 Extrusion Stem 7 Gap 8 Degassing Hole 12 Vacuum Pump 15 Outer Ring 16 Seal Ring 16a Projection 17 Spring 18 Degassing Hole 23 End Platen 24 Container Cylinder 25 Piston Rod 26 Stopper Block 27 Head block 28 Piston 30 Vacuum suction device 31 Hollow rod 56 Damiibos 57 Connection rod 58 Water supply pipe 59 Drain pipe 60 Blocking device 62 Cooling medium supply device 69 Connection bolt 70 Core block 71 Outer ring 72, 75 Passage 73 Pool groove 74 Radial cooling hole 83 Tip expansion part 85 Outer surface (extrusion surface) S Degassing space

Claims (1)

[Claims] 1. Air between the extrusion container and the billet,
When degassing before starting the extrusion of the billet, the container is temporarily stopped by the temporary stop mechanism before contacting the container with the die, and at the end face on the extrusion stem side of the extrusion container, the seal block is attached to the extrusion stem. In the closed state, cooling the inside of the damii block while pressing the billet, while keeping the die end face and the die side end face of the container out of contact with each other, into the container and the discard recess created by the shear blade during pre-extrusion. An extrusion molding method characterized in that accumulated air is deaerated so that a container starts contacting with a die immediately before completion of upsetting.