JPH08300036A - Extrusion method - Google Patents

Abstract

PURPOSE: To enable an extruded product to be obtained without blisters by deaerating air inside the container from the die side before starting extrusion of a billet. CONSTITUTION: Before entering the extrusion process of a billet 13, a fixed dummy block 70 is cooled from inside by introducing cooling water into radial cooling holes. Air between the extruding container 1 and the billet 13 is discharged before starting extrusion of the billet 13. For this purpose, the container 1 is once stopped before it is brought into contact with the die 3, discharging air through the gap between the die 3 and the container 1. In addition, cooling water is supplied to the cooling passage of the extruding stem 14 and of the dummy block 70. Air in the container 1 is deaerated from the die 3 side before starting extrusion of the billet 13, in a state where the seal block 61 is closed against the stem 14 extruding the billet 13, with the end face of the extruding container 1 while the fixed dummy block 70 is cooled. Thus, blisters are eliminated from an extruded product.

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 present invention relates to an improved extrusion molding method for effectively and efficiently excluding air in a 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.

Further, according to this method, the compressed air trapped on the die side during the billet upsetting process is released when the container is retracted, but the compressed air on the stem side remains trapped inside the billet. And extruded products will be generated as blister. In particular, when extrusion is performed using the fixed damy block attached to the stem tip, which is currently the mainstream, the temperature is lowered like the conventional free damy block to secure sufficient clearance between the container inner diameter and the damy outer diameter. Since it is not possible to do so, the air near both sides of the stem is not sufficiently discharged from the stem side, and air is particularly trapped inside the billet near the stem end surface.

Therefore, recently, for example, Japanese Laid-Open Patent Publication No. 3-4.
As described in Japanese Patent Publication No. 13, a pressure pad and a hollow extrusion stem are used at the tip of the stem in order to remove air from the stem side, and it is also considered to remove air during billet extrusion.

[0005]

However, in the air venting described above, even if the air on the stem side is released during pressurization of the billet, most of the air in the container and the billet, especially on the die side, is difficult to escape.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to call a barp cycle when a billet in a container is extruded from a die. An object of the present invention is to provide an extrusion molding method that does not require a degassing step.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and when the air between the extruding container and the billet is degassed before starting the extrusion of the billet, the container is removed. Before contacting the dice, the container is temporarily stopped by the temporary stop mechanism, and the air accumulated on the die side in the container is upset during the upset from the gap created so that the die end surface and the die side end surface of the container do not contact. While releasing it into the atmosphere through the gap,
Cooling water is passed through the cooling passage from the extrusion stem that pushes the billet loaded in the container to the die side to the fixed damy block provided at the tip of the extrusion stem, and while cooling the fixed damy block, the extrusion is performed. At the end face of the extrusion stem side of the container, with the seal block closed to the extrusion stem that is pushing the billet, make sure that the air accumulated in the container is degassed from the die side before starting the extrusion of the billet. I chose

[0008]

Operation: When the billet loaded in the container is pushed by the extrusion stem behind the billet and the billet is pressed against the die, the container is temporarily stopped by the temporary stop mechanism before the container is brought into contact with the die, and the end face of the die and the container The air accumulated on the die side in the container is discharged into the atmosphere through the gap from the gap formed by keeping the end faces of the die on the side not contacting each other. On the other hand, on the extruding stem side of the extruding container, cooling water is passed through a cooling passage leading to the fixed damy block provided with the extruding stem, and the billet is pressed by the extruding stem that has cooled the fixed damy block tip. At the same time, with the seal block closed, the air inside the container is forcibly vacuumed before it is compressed between the container and the billet and extruding stem, so this compressed air is sucked after the billet is compressed by the stem. The so-called degassing step can be omitted.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings.

FIG. 1 is an explanatory view showing an embodiment of a degassing system for an extrusion container according to the present invention, FIG. 2 is a sectional view of an extrusion stem and a fixed damy block having an internal cooling device, and FIG. 1 is a front view seen from A to A, FIG. 4 is an explanatory view of vacuum suction from the extrusion stem side of the container after pressing the tip of the billet against the die, and FIG. 5 is the operation of the temporary stop mechanism provided in the container cylinder. Explanatory drawing and FIG. 6 are conceptual diagrams showing how to collapse the billet pressurized in the container.

As shown in FIG. 2, a portion B on the piston head side of the container cylinder 33, which is installed on the end platen 32 of FIG. 1 and which slides the container tire 2 and the container 1, has a moving stopper block 34 as a main portion. The head block 35 also functions as a stopper, and has a structure having a temporary stop mechanism 30 capable of rapidly stopping the piston 37 at the maximum distance S in the range in which the moving stopper block 34 moves. In FIG. 5, 36 is a cylinder tube which constitutes a part of the cylinder body, 35 is a head block at the rear of the cylinder body, and 38 is a piston rod.
A hollow rod 40 having a plurality of oil passage holes 39 arranged in a zigzag pattern in the axial direction is integrally attached to the rear axial center of the piston rod 38, which is the head side of the piston 37, by screws or the like. It was

In the head block 35 of the cylinder, a movable stopper block 34 that can move in the S axial direction in the cylinder axial direction is slidably incorporated, and a hole 41 is provided in the axial center portion of the movable stopper block 34 to form the hollow rod. The structure is such that 40 can be slidably inserted. Movement stopper block 34
Is composed of a piston portion 34a and a rod portion 34b facing toward the piston 37 side, and an oil passage 42 that penetrates in the radial direction and communicates with the rear portion of the hole 41 is formed in a part of the piston portion 34a. Provided.

Reference numeral 43 designates a piston 37 and a head block 35.
And an oil chamber between the moving stopper block 34, 44, an oil inlet / outlet port for the oil chamber 43, and 45, an oil chamber between the front surface of the rear wall portion formed by the plug of the head block 35 and the rear surface of the moving stopper block 34. 46 is a passage in the head block 35 communicating with the oil chamber 45, and 47 is a passage in the head block 35 communicating with the passage 42.

The hydraulic oil can be supplied to or discharged from the oil inlet / outlet 44 to the oil chamber 43, the passage 46 connected to the oil chamber 45, and the passage 47 connected to the passage 42, respectively, through conduits 48, 49, and 50, respectively. I did it. Reference numeral 51 is a valve having a flow rate adjusting valve 52 and a check valve 53 provided in parallel in the pipe 50, and 54 is a solenoid SOL. An electromagnetic switching valve having A,
55 is a pilot check valve provided in the pipeline 49, 56
Is a solenoid SOL. B is an electromagnetic switching valve, 57 is a relief valve provided in the conduit 48, and 58 is a solenoid SO
L. An electromagnetic switching valve having C, 59 is a tank, which are connected as shown in FIG. 5, and one of the pipelines 48 is connected to the container cylinder 33 through an electromagnetic switching valve (not shown) for forward / backward movement. It is connected to a pump not shown.

In FIG. 1, reference numeral 3 is a die, and the outer periphery of the die 3 is slidably fitted and held on the inner peripheral surface of the die ring 5. 6 is a gap and is a container cylinder 33
The container 1 and the dice 3 by the temporary stop mechanism provided inside
A gap 6 of, for example, 2 to 3 mm is formed between the and die ring 5. Reference numeral 31 denotes a gap between the inner peripheral surface of the container 1 and the outer peripheral surface of the billet 13, which is also a deaeration space.

On the other hand, an extrusion stem 14 for pushing the billet 13 in
A fixed damy block 70 that can be brought into close contact with the inner surface of the container 1 is provided at the tip of the container.

Next, a sealing device 60 for sealing the extruding stem 14 side in the container 1 is disposed on the end surface of the container 1 on the extruding stem 14 side as shown in FIG. On the end surface of the container 1 on the extrusion stem 14 side, a split seal block 61 is provided so as to be openable and closable in a direction perpendicular to the axial direction of the container 1, and when the seal block 61 is closed, the seal block 61 is provided on the inner peripheral surface of the seal block 61. The seal packing 62 is provided so as to be in close contact with the outer peripheral surface of the extrusion stem 14.

Next, a sealing device 60 for excluding air on the side of the extrusion stem 14 in the container 1 is disposed on the end surface of the container 1 on the side of the extrusion stem 14 as shown in FIGS. 3 and 4. On the end surface of the container 1 on the extrusion stem 14 side, a split seal block 61 is provided so as to be openable and closable in a direction perpendicular to the axial direction of the container 1.
When it is closed, it can be brought into close contact with the outer peripheral surface of the extruding stem 14 through the seal packing 62 provided on the inner peripheral surface of the seal block 61.

Reference numeral 63 is a guide plate, and both blocks of the seal block 61 can be opened and closed by a cylinder 64. Reference numerals 62 and 65 are seal packings, and a deaeration hole 66 is provided in a part of the seal block 61.
The deaeration hole 66 is connected to the vacuum tank 20 via a pipe 8a. Reference numeral 26 is an electromagnetic switching valve, and 67 is a heat insulating material so that part of the heat of heating the container 1 is not transferred to the sealing device 60 by heat conduction, and the guide plate 63 described above is provided on the upper surface of the heat insulating material 67. It is arranged via the cover plate 68 arranged. Reference numeral 21 is a vacuum pump, 22 is a motor, and 69 is a tip diameter expansion portion of the extrusion stem 14.

On the other hand, the structure on the side of the extruding stem 14 is not shown in the drawing when the fixed damy block 70 and the extruding stem 14 are bayonet-connected via the bayonet block 72 as shown in FIG. In some cases, the fixed damy block 70 and the extrusion stem 14 may be directly screwed together.

First, the structure in which the fixed damy block 70 and the extruding stem 14 are bayonet-bonded will be described in detail as a representative. In FIG. 2, 1 is a container,
Reference numeral 14 is a tubular extrusion stem, and 70 is a fixed damy block fixedly provided on the front surface of the extrusion stem 14 and slidably provided in the container 1. Extrusion stem 1
As shown in FIG. 1, the rear end of the No. 4 is fixed to the crosshead 75 via the stem holder 73 and the pressure ring 74.

A bayonet block 72 is disposed on the front surface of the extruding stem 14, and a distal end portion of a connection rod 76 having a circular outer diameter cross section is attached by a screw to a rear half portion of the bayonet block 72. Installed. The rear end portion of the connection rod 76 is a large diameter portion 76a 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 14.

The front half of the bayonet block 72 is of the bayonet type, and three projections 72a are arranged at equal intervals, for example. On the other hand, a recess 77 engageable with the projection 72a is provided on the side of the dami boss 77 on the side to be mounted.
a are provided at equal intervals, and when mounted, the projections 72a of the bayonet block 72 and the recesses 7 on the dami boss 77 side are mounted.
7a is engaged and inserted, and the damie boss 77 is rotated about 60 degrees so that the damie boss 77 can be reliably and quickly attached to and removed from the bayonet block 72.

A through hole is bored in the connection rod 76 in the axial direction, and a water supply pipe 78,
A drain pipe 79 is provided. The water pipe 78 and the drain pipe 79 that form the cooling pipe 80 are firmly attached by welding to the holes 82 and 83 of the cooling pipe tip block 81, and the rear end extends into the pressure ring 74. .

The end of the water supply pipe 78 has a pressure ring 7
It is connected to a cooling water supply pump (not shown) via a pipe passage 84, an opening / closing valve 85, and a pipe 86 inside the nozzle 4. The end of the drainage pipe 79 is connected to the drainage port 88 via a passage 87 formed by a pipe in the pressure ring 74. Inner peripheral surface of extrusion stem 14 and connection rod 76
A small gap is provided between the outer peripheral surface and the outer peripheral surface in order to hold the core of the connection rod 76 in a flexible state. In addition, a slight gap is provided between the inner peripheral surface of the connection rod 76 and the outer peripheral surfaces of the water supply pipe 78 and the drain pipe 79 so that the connection rod 76 is not directly cooled. A small gap is provided between the inner peripheral surface of the connection rod 76 and the cooling pipe tip block 81 to keep the core in a flexible state.

In this case, since a through hole is provided in the connection rod 76 to pass the water supply pipe 78 and the drain pipe 79, the connection rod 76 is not directly cooled, and therefore the temperature difference between the extruding stem 14 and the connection rod 76. And the flexibility of the core of the fixed damy block 70 is not impaired. Although the hole 82 in the cooling pipe tip block 81 is provided so as to penetrate therethrough, the front end portion of the hole 82 communicates with the radial cooling hole 98 via the passage 82a.

In the front half of the dami boss 77, a small cylindrical protrusion 92 provided in the center of the core block 91 is inserted into the center through hole 90 of the dami boss 77, and the connection is made from the rear end side of the dami boss 77. The bolt 93 is screwed into the threaded portion of the small cylindrical projection 92, and the connection bolt 93 is tightened to strongly contact the core block 91 with the dami boss 77.

A cylindrical outer ring 94 is fixed to the outer periphery of the front side of the dami boss 77. Further, between the rear end surface of the core block 91 and the front end surface of the dami boss 77,
The tip of the outer ring 94 and the outer surface 9 of the core block 91
5 has a gap corresponding to a step with the core block 91. When the core block 91 is pushed backward during extrusion, the core block 91
The rear end face of the damy boss 77 contacts the front end face. The outer ring 94 is expanded during extrusion (pressurization), but returns to its original size after the end of extrusion (pressurization), and the aluminum billet 13 press-filled in the container 1 does not adhere during the retreat of the stem and is smooth. It is ready for operation.

The core block 91, the damy boss 77 having the outer ring 94, and the like form a fixed damy block 70 integrally. Therefore, the outer peripheral surface on the front end side of the outer ring 94 has a size with a small gap from the inner peripheral surface of the container 1. Also, the core block 9
The outer peripheral portion of the front end of No. 1 has a taper surface portion 96 that widens to the front side so that it can be closely attached to the taper surface portion 96 of the inner peripheral portion of the front end of the outer ring 94.

A passage 82a for passing the cooling water absorbed from the water supply pipe 78 is provided at the central axis of the core block 91 and the projection 92, and the tip of this passage 82a is the outer surface of the core block 91. It is extended to around 95.

As shown in FIG. 2, a plurality of radial cooling holes 98 (eight in this embodiment) extending radially from the tip of the passage 82a to the outer ring 94 are provided.

A passage 99 is provided in the axial direction from the outer peripheral end of the radial cooling hole 98 to the core block 91 from the dummy boss 77 to the core block 91, and is connected to the opening 89. Here, reference numerals 100, 101, 102, 103
Indicates a plug, and 105, 106 and 107 indicate heat resistant O-rings, respectively.

Next, the extrusion molding method will be described.

First, before starting the billet 13 extruding step, in order to indirectly cool the billet 13, a cooling water supply pump (not shown) is activated to introduce cooling water into the radial cooling holes 98 to fix the fix dame. The i-block 70 is cooled from the inside. At this time, the cooling water enters from the rear of the extrusion stem 14 and the connection rod 7 inside the extrusion stem 14 is cooled.
6, the cooling water discharged from the passage 82a, the radial cooling holes 98, the passage 99, the opening 89, the drain pipe 79, and the drain outlet 88 passes through the pipe to the tank ( (Not shown).

Next, the container 1 is advanced to raise a billet loader (not shown) with a gap 6 of 2 to 3 mm between the container 1 and the die ring 5. Then, the billet 13 is put into the container 1 by the action of the extrusion stem 14, and the piston 3 is first passed through a hydraulic circuit (not shown).
The hydraulic oil acts on the front surface of 7 to retract the piston 37 (FIG. 5 (1)). At this time, the extrusion stem 14 is also advanced at the same time. At this time, when the tip E of the hollow rod 40 attached to the piston 37 moves to the tip F of the movement stopper block 34, the SOL. B is ON, SOL. A
Is OFF, SOL. C is OFF, and the retreating speed of the piston 37 is relatively high. At this time, since the pilot check valve 55 acts as a check valve, the movement stopper block 34 is at the forward limit position as shown in FIG. When the piston 37 retreats at a high speed, most of the oil in the oil chamber 43 is discharged through the pipe line 48, but a part of the oil is discharged from the hole 4
1, it may be discharged to the tank 59 through the passages 42 and 47, the pipeline 50, the flow rate adjusting valve 52, and the electromagnetic switching valve 54.

When the tip E of the hollow rod 40 reaches the tip F of the movement stopper block 34, SOL. B is ON, SOL. A remains OFF and SO
L. Switch C to ON. Then, the relief valve 57
Is activated and a little pressure is generated in the pipe 48, and the piston 3
Since 7 becomes a little low speed, pressure starts to be applied to the discharge from the inlet / outlet port 44.

While the hollow rod 40 begins to enter the hole 41 and the tip surface portion D of the piston 37 moves to the tip portion F of the movement stopper block 34, the SOL. B is O
N, SOL. C is ON, SOL. A is off. Then, the communication hole 39 for oil passage is blocked one after another, the hydraulic pressure in the oil chamber 43 is smoothly increased, and the retreat speed of the piston 37 is also reduced. In this state, piston 3
7 continues to retreat, and the tip end surface portion D of the piston 37 contacts the tip end portion F of the movement stopper block 34. At this time, the piston 37 completes the midway stop due to the action of the movement stopper block 34. And the movement stopper block 3
By the action of 4, the accuracy of the stop position in the middle of the stroke is sufficiently ensured. At this time, the gap 6 between the container 1 and the die 3 is, for example, 2 to 3 mm. The state at this time is shown in FIG. At this time, as shown in FIG. 1, there is air in the deaeration space 31 between the container 1 and the billet 13.

When this operation ends, the billet 13
The billet loader (not shown) rises with the
When the extrusion stem 14 is moved forward, the billet 13 is pushed into the container 1. In this state, the billet 13 is loaded into the container 1 by the forward movement of the extrusion stem 14, and the tip surface of the billet 13 is set to the die 3. Hit This state is shown in Figure 6.
It shows in (1). At this time, air is present in the deaeration space 31 between the container 1 and the billet 13.

Next, the billet 13 is pushed into the container 1 as the extruding stem 14 advances, and the cylinder 64 of the sealing device 60 arranged on the extruding stem 14 side of the container 1 is actuated to operate the two billets. Split seal block 61
To close the space between the extrusion stem 14 and the container 1.

When the billet 13 is pushed into the container 1 and comes into contact with the die 3, the pressure in the side cylinder (not shown) starts to rise, and at the same time, the electromagnetic switching valve 26 is excited to ventilate the inside of the container 1 and the vacuum tank 20. Vacuum suction is performed to make it possible.

The forward movement of the extrusion stem 14 is continuously performed by switching from the side cylinder to the main cylinder (not shown), and the extrusion stem 14 advances to start upset. If this state is continued, the billet 1 on the extrusion stem 14 side
By the action of the vacuum tank 20 when 3 comes into close contact with the container 1, the closed air on the side of the extrusion stem 14 passes through the deaeration hole 66 provided in a part of the split seal block 61 and above the pipe 8a. It is sucked and discharged to the vacuum tank 20 via the electromagnetic switching valve 26.

On the other hand, from the time when the extrusion stem 14 moves forward to start upsetting and the billet 13 on the extrusion stem 14 side comes into close contact with the container 1, the degassing space 31 is extruded from the die 3 side as shown in FIG. 6 (2). The air in the deaeration space 31 on the side of the die 14 on the side of the die 3 is naturally discharged from the gap 6 into the atmosphere as the upset progresses.

As shown in FIGS. 6 (1), (2) and (3), the degassing space 31 between the container 1 and the billet 13 is the extrusion stem 14 and the billet 13 moves from S ₁ to S ₃ in the die 3 direction.
It can be seen that the deaeration space 31 is pushed toward the die 3 side if the pressure is sequentially applied up to.

Even after the start of degassing by suction, the extrusion stem 14
Continues to move forward, crushing the billet 13. Then, the billet 13 is filled in the container 1 to complete the upset. Immediately after completing the upset, Container 1
Is brought into contact with the die 3 (FIG. 6 (4)). Next, the extrusion is continued, and the product is extruded from the die 3.

[0045]

As is clear from the above description, 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 brought into contact with the die. The container is temporarily stopped by the temporary stop mechanism to prevent the end face of the die from contacting the end face of the die on the die side, and the air accumulated on the die side inside the container is upset into the atmosphere during the upset. The billet loaded in the container is discharged to the die and the cooling water is passed through the cooling passage from the extrusion stem to the fixed damy block provided at the tip of the extruded stem to cool the fixed damy block. However, at the end face of the extrusion container on the extrusion stem side, a seal block is attached to the extrusion stem while the billet is being pressed. In the closed state, the air accumulated in the container before starting the extrusion of the billet was degassed from the die side, so that the end face of the extrusion stem side during the upset has the seal block closed. Since the air accumulated on the side of the extrusion stem in the container is degassed in vacuum, there is no risk of air flowing backward from the sealing surface and the fixed damy block is cooled, so the vicinity of the end surface of the extrusion stem 14 Compared with the case where the fixed damey block 70 is not cooled, the flow of metal at the time of upsetting the outer periphery of the billet 13 becomes closer to the end face of the extrusion stem 14,
Air is prevented from being entrained inside and discharged as a residual material of extrusion, and by cooling the fixed damy block 70, thermal expansion due to a temperature difference between the inner diameter of the container 1 and the outer diameter of the fixed damy block 70. The clearance is further ensured by increasing the difference in size and the vacuum degassing is easily performed from the extrusion stem 14 side, so that the blister does not get caught in the extruded product and the extruded product without the blister is obtained. Also, the air in the degassing space on the die side is spontaneously released into the atmosphere through the gap between the die and the container as the upset progresses, so even if there is residual air at the corners inside the container on the die end surface side, Are eliminated as discards (metal dregs), eliminating the formation of blisters in extruded products.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a degassing system for an extrusion container according to the present invention.

FIG. 2 is a cross-sectional view of an extrusion stem and fixed damy block with internal cooling.

FIG. 3 is a front view as seen from AA of FIG.

FIG. 4 is an explanatory diagram of vacuum suction from the extrusion stem side of the container after pressing the tip of the billet against a die.

FIG. 5 is an operation explanatory view of a temporary stop mechanism provided in the container cylinder.

FIG. 6 is a conceptual diagram showing how to collapse a billet pressurized in a container.

[Explanation of symbols]

 1 Container 2 Container Tire 3 Die 6 Gap 13 Billet 14 Extrusion Stem 20 Vacuum Tank 21 Vacuum Pump 26 Electromagnetic Switching Valve 30 Temporary Stop Mechanism 31 Deaeration Space 33 Container Cylinder 34 Movement Stopper Block 35 Head Block 37 Piston 39 Communication Hole 40 Hollow Rod 51 valve 52 flow control valve 53 check valve 54, 56, 58 electromagnetic switching valve 60 sealing device 61 seal block 62, 65 seal packing 63 guide plate 64 cylinder 66 deaeration hole 67 heat insulating material 68 cover plate 70 fixed damy block 72 Bayonet block 73 Stem holder 74 Pressure ring 75 Crosshead 77 Damiivos 78 Water supply pipe 79 Drain pipe 88 Drainage port 91 Core block 93 Connection bolt 94 Outer Grayed 95 outer surface 96 tapered surface portion 98 radially cooling holes

Claims (1)

[Claims] 1. Air between the extrusion container and the billet,
When degassing before starting the extrusion of billet, a gap created by temporarily stopping the container by the temporary stop mechanism before contacting the container with the die so that the die end surface and the die side end surface of the container do not contact each other. While releasing the air accumulated on the die side in the container from the gap into the atmosphere during upsetting, push the billet loaded in the container to the die side from the extrusion stem to the fixed type of the extruding stem. Cooling water is passed through the cooling passage leading to the damey block, and while the fixed damy block is being cooled, at the end face of the extrusion container on the extrusion stem side, the seal block is closed with respect to the extrusion stem in which the billet is being pushed. , Degas the air accumulated in the container before starting the billet extrusion from the die side. Extrusion molding method is characterized in that as.