JP2000005812A - Hot extruding method for metallic material and its equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove the material skin layer in dead metal during extrusion, and obtain a good extruded material without entrainment defects. SOLUTION: A heated metallic material 2 is contained in a cylindrical container 3, and one end of the container 3 is plugged with a die 11 and the other end with a disk-like dummy block 5, and the dummy block 5 is moved forward in the extruding direction and then the metallic material 2 is pressed via the dummy block 5 and extruded through the die hole of the die 11. In this case, between the container 3 and the die 11, a clearance is formed to be larger than a skin layer 8 thickness of the metallic material 2, and through this clearance, a shell 10 containing the material skin layer 8 is discharged to the forward side in the extruding direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for hot extrusion of a metal material, and more particularly to a method and an apparatus for directly extruding a metal material hot.

[0002]

2. Description of the Related Art In general, an extruding apparatus used for hot extrusion of a metal material includes, as shown in FIG. 6A, a cylindrical container 33 for accommodating a heated metal material 2 therein.
A die 31 provided on one end side (front side in the extrusion direction; left side in FIG. 6) of the container 2 and a container 33 from the other end side (rear side in the extrusion direction; right side in FIG. 6) of the container 33
It has a disk-shaped dummy block 5 inserted therein, and a stem 4 which is in contact with the dummy block 5 and which is driven in connection with a main ram (not shown).

In the extrusion method, after the heated metal material 2 is inserted into the container 33, the dummy block 5 is inserted into the container 33 from the rear side in the extrusion direction of the container 33, and then the entire container 33 is moved in the extrusion direction. The container 33 is moved to the front side and the front end of the container 33 in the extrusion direction is closed by the die 31 seated on the die slide 6. Thereafter, the stem 4 is advanced to the front side in the extrusion direction to remove the metal material 2 through the dummy block 5. The extruded material (product or material) 7 having a predetermined shape is extruded from the die hole 31a of the die 31 by pressing. At this time, the die surface 3 of the container 33 and the die 31
The surface in contact with 1d is a pressure receiving surface that receives the container sealing force during extrusion.

Here, in the hot direct extrusion method, the metal material 2 is used.
Is heated to a high temperature, an oxide film layer is formed on the surface of the metal material 2. In addition, the surface properties of the metal material 2 are poor, and there are also irregularities and foreign matter. In the direct extrusion method, the friction between the container 33 and the metal material 2 causes
Area where material deformation does not occur during extrusion (dead metal) 9
Is formed on the metal material 2 on the front side in the extrusion direction.

[0005]

However, during extrusion, as shown in FIG. 6 (b), the material skin layer 8 containing the oxide film layer and the foreign matter forms an interface between the metal material 2 and the dead metal 9. The flow of the metal material 2 along F ₁ and the container 33 along the interface F ₂ between the metal material 2 and the dummy block 5
Is drawn into the extruded material 7 by the flow of the metal material 2 toward the center of the extruded material 7, causing surface defects and internal defects of the extruded material 7. These defects are collectively referred to as entrainment defects 12
It is called. Further, since the material skin layer 8 gradually accumulates in the dead metal 9, if the extrusion is advanced until the remaining filling length L _{1 of} the metal material 2 becomes equal to or less than the dead metal length L ₂ , the dead metal 9 is removed. Shape collapses, dead metal 9
The material skin layer 8 accumulated therein flows into the extruded material 7 in a large amount, and as a result, entrapment defects 12 increase.

Therefore, in the hot direct extrusion method,
Order to prevent entrapment defect 12 is provided with a predetermined gap t ₁ between the container 33 and the dummy block 5 the diameter sufficiently smaller than the inside diameter of the container 2 of the dummy block 5. By discharging the material skin layer 8 from the gap t ₁ to the rear side in the extrusion direction (left side in FIG. 6) as the shell 10, the shell 10 adheres and remains on the inner surface of the container 33, and the entrapment defect 12 is prevented as much as possible. However, if this gap t ₁ is too large, it becomes backward extrusion and the gap t
_A large amount of the metal material 2 flows out from ₁ and the yield deteriorates.
Therefore, there is a limitation that the size of the gap t ₁ must be within a range that does not result in backward extrusion.

[0007] As shown in FIG.
Abuts on the lower surface of the container 33 (the lower surface in FIG. 7) by its own weight.
It cannot be held at the center, and the upper surface of the container 33 (FIG. 7)
Although the gap between the container 33 and the dummy block 5 in the upper side) of a medium becomes t _2, the gap in the container 33 bottom surface almost disappears. For this reason,
The thickness of the shell 10 discharged to the rear side in the extrusion direction of the dummy block 5 becomes uneven on the inner periphery of the container 33, and the thickness of the shell 10 is reduced (the side on which the shell 10 is not easily discharged; FIG. 7). Extruded material 7 on the lower side)
Entrainment defects 12 occur in

Furthermore, it is impossible to discharge the material skin layer 8 accumulated in the dead metal 9 from the gap t ₁ (or t ₂ ) between the dummy block 5 and the container 33.

That is, in the conventional hot direct extrusion method of a metal material, there are these problems.
It was very difficult to prevent 2 completely.

Therefore, the present invention solves the above-mentioned problems, and it is possible to remove a material skin layer in dead metal during extrusion, and to obtain a good extruded material free from entrainment defects. An object of the present invention is to provide a hot extrusion method and a device therefor.

[0011]

According to a first aspect of the present invention, a heated metal material is housed in a cylindrical container, and one end of the container is closed with a die and the other end is closed. After the dummy block is closed with a disk-shaped dummy block, and the dummy block is advanced forward in the extrusion direction, the metal material is pressed through the dummy block and hot-extruded from the die hole of the die. In the method, a gap is formed between the container and the die so as to have a thickness equal to or greater than a thickness of a material skin layer formed on a surface portion of the metal material, and a shell including the material skin layer is formed through the gap. Is also discharged to the front side in the extrusion direction.

According to a second aspect of the present invention, an enlarged diameter chamber is formed between the outer periphery of the die and the inner surface of the container, and the shell discharged through the gap is retained in the enlarged diameter chamber. This is a hot extrusion method for metal materials.

According to a third aspect of the present invention, the heated metal material is accommodated in a cylindrical container, and one end of the container is closed with a die and the other end is closed with a disk-shaped dummy block.
After moving the dummy block forward in the extrusion direction,
In the method of hot extrusion of a metal material, which presses the metal material through a dummy block and extrudes from a die hole of the die, an enlarged portion is formed at one end of the container, and between the inner surface of the container and the container. A die having a protruding portion having a gap larger than the thickness of the material skin layer formed on the surface portion of the metal material is provided by being fitted to the enlarged diameter portion.

According to a fourth aspect of the present invention, an enlarged diameter chamber for retaining the material skin layer as a shell is formed between the outer periphery of the projecting portion of the die and the inner surface of the enlarged diameter portion of the container. Is a hot extrusion apparatus for metal materials.

According to the above configuration, the material skin layer in the dead metal can be removed forward in the extrusion direction during the extrusion, and a good extruded material free from entrainment defects can be obtained.

According to a fifth aspect of the present invention, there is provided the hot extrusion apparatus for a metal material according to the third or fourth aspect, wherein the die is a taper die having a tapered surface in contact with the metal material.

According to this configuration, no dead metal is formed in the container during extrusion, and the yield of the metal material is improved.

[0018]

Embodiments of the present invention will be described below.

In order to obtain a good extruded material having no entanglement defects, the following conditions are required.

An oxide film layer formed on the surface of the metal material and a material skin layer containing foreign substances and the like are prevented from flowing into the extruded material.

When the material skin layer is discharged as a shell to reduce entrapment defects, the thickness of the shell is made uniform over the entire inner circumference of the container.

The material skin layer accumulated in the dead metal is sequentially discharged during extrusion.

FIG. 1 is a vertical sectional structural view of a die and a container in the metal material hot extrusion apparatus of the present invention. The same members as those in FIGS. 5 and 6 are denoted by the same reference numerals.

As shown in FIG. 1, the structure of the die and the container in the metal material hot extrusion apparatus of the present invention is such that one end side of a cylindrical container 3 having an inner diameter D (the front side in the extrusion direction; FIG. in the left) are formed enlarged diameter portion 3a of the inner diameter D ₂ is in, the one end of the container 3, including the enlarged diameter portion 3a, the outer diameter of the cylindrical protruding portion 1a and the outer diameter is D ₁ D ₃ of the flange portion longitudinal sectional convex die 1 provided with the 1b
Are fitted with the protruding portion 1a side as a tip. The die 1 is seated on a die slide 6.

Here, the outer diameter D ₁ of the protruding portion 1a is sufficiently smaller than the inner diameter D _{2 of the} container 3, and the outer diameter D ₃ of the flange portion 1b is smaller than the inner diameter D ₂ of the enlarged diameter portion 3a. Has a small diameter, and a gap t ₃ is formed over the entire circumference between the protrusion 1 a and the inner diameter of the container 3. Through this gap t _3, the material skin layer accumulated during the dead metal formed by extrusion, sequential discharges in the extrusion direction front side as the shell. Further, when the die 1 is fitted to the container 3, the flange portion 1b does not contact the step portion 3b which is a boundary between the enlarged diameter portion 3a and the inner diameter portion, and the length L ₃
Are fitted at intervals. The spacing, i.e., the projecting portion 1a, the flange portion 1b, the enlarged diameter portion 3a, and the stepped portion a ring-shaped space is enlarged chamber 14 becomes, which is surrounded by 3b, and is discharged through the gap t ₃ in the enlarged chamber 14 Let the shell stay.

Further, in the conventional hot extruder, as shown in FIG. 6, the surface where the container 33 and the die surface 31d of the die 31 are in contact is a pressure receiving surface which receives the container sealing force during the extrusion. . On the other hand, in the hot extrusion apparatus of the present invention, since the die 1 is inserted (fitted) into the container 3, the container 3 and the die surface 1d of the die 1 are not in surface contact, The pressure receiving surface itself does not exist. For this reason, the die 1 and the die slide 6
A ring-shaped stopper member 15 surrounding the whole body and connected to the extruder main body is provided.
The contact surface between the container 5 and the container 3 was a pressure receiving surface. Here, as the interval length of the flange portion 1b and the step portion 3b at the time of contact of the stopper member 15 and the container 3 is L _3,
The position of the stopper member 15 is adjusted in advance.

Further, the size of the gap t ₃ formed between the die 1 and the container 3 is not particularly limited. However, by discharging the shell forward in the extrusion direction, it is possible to extrude the metal material. Since a frictional resistance is generated, it is possible to make the gap larger than a gap (not shown) formed between the inner diameter portion of the container 3 and a dummy block (not shown). However, the maximum value of the gap t ₃ is to be determined by the size extrusion.

Further, the size of the diameter expansion chamber 14 serving as a shell reservoir is not particularly limited, but can be estimated from the gap t ₃ and the amount of extruding movement. combined to determine the internal diameter D ₂ of the spacing L ₃ and the enlarged diameter portion 3a and.

FIG. 2 shows a first modification of the die shown in FIG.
FIG. 3 shows a second modification of the dice shown in FIG.
The same members as those in FIG. 1 are denoted by the same reference numerals.

As shown in FIG. 2, instead of a flat die having a flat die surface 1d in FIG.
1a, a taper die 11 tapered so that the center of the tip of the die surface 11d becomes a concave portion, that is,
A die 11 tapered so as to have a shape substantially similar to the shape of the dead metal 9 as shown in FIG.

Further, as shown in FIG.₁In
Cylindrical projection 21a having an outer diameter of D _ThreeFirst flange part of
21b and the outer diameter is D_Four(> D_Three) 2nd flange part
A die 21 having 21c may be used. in this case,
The second flange portion 21c comes into surface contact with one end surface of the container 3.
Until the die 21 is inserted into the container 3
The pressure receiving surface 16 is formed between the container 3 and the die 21
Therefore, the stopper member 1 shown in FIGS.
5 becomes unnecessary.

Next, the method of the present invention will be described.

FIG. 4 is a schematic diagram when extrusion is performed using the hot extrusion device having a die and a container structure in FIG. 2, and FIG. 5 is a schematic diagram after the extrusion in FIG. 4 is completed. The same members as those in FIG. 2 are denoted by the same reference numerals.

As shown in FIG. 4, first, a heated metal material 2 is inserted into a cylindrical container 3, and then the container 3 is heated.
The dummy block 5 is inserted into the container 3 from the other end side (the rear side in the pushing direction; right side in FIG. 4).

Thereafter, the entire container 3 is advanced forward (to the left in FIG. 4) in the pushing direction to a position where the container 3 comes into contact with the stopper member 15, and one end of the container 3 in which the enlarged diameter portion 3a is formed (forward in the pushing direction). A die (taper die) 11 seated on the die slide 6 is fitted to the die slide 6 (left side in FIG. 4).

Then, from the rear side in the extrusion direction of the container 3, the stem 4 is advanced forward in the extrusion direction to press the metal material 2 through the dummy block 5, and the extruded material having a predetermined shape is passed through the die hole of the die 11. (Product or material) 7 is extruded forward in the extrusion direction.

[0037] Thereafter, shell 10 discharged through the gap t ₃ is enlarged chamber is formed in communication with the clearance t ₃ 1
4 is retained. Further, a part of the material skin layer 8 passes through a gap formed between the inner diameter portion of the container 3 and the dummy block 5 and is discharged as a shell 10 to the rear side in the extrusion direction.

After the end of the extrusion, as shown in FIG. 5, the container 3 and the stem 4 are retracted backward in the extrusion direction to separate the container 3 and the die 11, and the extruded material 7 is cut by the exclusive shear 17. I do. Thereafter, after removing the metal material 2 remaining in the container 3 and the shell 10 in the expanded diameter chamber 14 and the container 3, hot extrusion in the next step is performed.

According to the hot extrusion method for a metal material of the present invention, the die surface 1
1d is tapered so as to have a shape substantially similar to the shape of the dead metal. Therefore, when the extruded material 7 is extruded from the die hole of the die 11, the extrusion flow of the metal material 2 in the container 3 is performed. And the dead metal itself is not formed. This eliminates the flow of the metal material 2 along the boundary surface F ₁ of the metal material 2 and dead metal 9 as shown in FIG. 6, including such oxide film layer or foreign matter on the surface of the metallic material 2 material The skin layer 8 is not guided toward the dice holes of the dice 11 and the dice 1
The shell 10 is sequentially discharged to the front side in the extrusion direction through a gap t ₃ formed between the first protrusion 11 a and the inner diameter of the container 3. At this time, the shell 10 is the container 3
Is discharged with a uniform thickness over the entire inner circumference of

Here, the inner diameter of the container 3 and the projection 11
By setting the size of the gap t ₃ between the first and second members a to an appropriate value, the material skin layer 8 is almost entirely discharged as the shell 10 through the gap t ₃ . The material skin layer 8
Are sequentially discharged during extrusion, so that the interface F ₂ between the metal material 2 and the dummy block 5 as shown in FIGS.
The material skin layer 8 is not drawn into the flow of the metal material 2 along the flow toward the center of the container 33 (there is no internal defect). With these, the entrainment defect in the extruded material 7 can be almost completely eliminated, and the quality of the extruded material 7 can be improved.

The shell 1 discharged to the front side in the extrusion direction
0 is retained in the expansion chamber 14 so that when the container 3 is separated from the die 11, the shell 10 is stored in the expansion section 3 a of the container 3, and post-processing of the shell 10 after the end of extrusion is easy. is there. Furthermore, in order to make the thickness of the shell 10 uniform, it is necessary to align the die 11 with the container 3.
The self-alignment is possible only by making the clearance between the outer diameter portion 3a and the outer diameter portion 3a as small as possible, and inserting (fitting) the flange portion 11b into the enlarged diameter portion 3a.

The dies 1, 2 shown in FIGS.
1 and hot extrusion may be performed. In this case, although entrainment defects are reduced as compared with the case where hot extrusion is performed using the conventional hot extrusion apparatus shown in FIGS. 6 and 7, Since the die surfaces 1d and 21d are flat and the dead metal is formed near the contact portion between the dies 1 and 21 and the container 3, the metal flows into the extruded material 7 along the boundary surface between the metal material 2 and the dead metal. It is difficult to completely prevent the flow of the material skin layer 8.

[0043]

In summary, according to the present invention, a gap is formed between the container and the die, the gap having a thickness greater than the thickness of the material skin layer formed on the surface layer of the metal material. By successively discharging the material skin layer as a shell to the front side in the extrusion direction through the through hole, an excellent effect of obtaining a good extruded material free from entrainment defects is exhibited.

[Brief description of the drawings]

FIG. 1 is a vertical sectional structural view of a die and a container in a metal material hot extrusion apparatus of the present invention.

FIG. 2 is a longitudinal sectional view showing a first modification of the dice shown in FIG.

FIG. 3 is a longitudinal sectional structural view showing a second modification of the dice in FIG.

FIG. 4 is a schematic diagram when extrusion is performed using a hot extrusion apparatus having a die and a container structure in FIG. 2;

FIG. 5 is a schematic diagram after the extrusion in FIG. 4 is completed.

FIG. 6 is a schematic vertical cross-sectional view showing a hot extrusion state using a conventional metal material hot extrusion apparatus.

FIG. 7 is a schematic longitudinal sectional view showing a state of hot extrusion using a conventional hot extrusion apparatus for metal materials.

[Explanation of symbols]

1, 11, 21 die 1a, 11a, 21a projecting portions 2 metal material 3 container 3a enlarged diameter portion 5 dummy block 8 material skin layer 10 shell 14 enlarged diameter chamber t ₃ Clearance

Claims (5)

[Claims] 1. A heated metal material is accommodated in a cylindrical container, and one end of the container is closed with a die, and the other end is closed with a disk-shaped dummy block. After being advanced, the metal material is pressed through a dummy block, and the metal material is extruded from a die hole of the die.
A gap is formed between the container and the die so as to have a thickness equal to or greater than a thickness of a material skin layer formed on a surface portion of the metal material, and a shell including the material skin layer is pushed through the gap in a pushing direction. A method of hot extrusion of a metal material, wherein the metal material is also discharged to the front side. 2. A heat-generating metal material according to claim 1, wherein a diameter-expanding chamber is formed between an outer periphery of said die and an inner surface of said container, and said shell discharged through said gap stays in said diameter-expanding chamber. Extrusion processing method. 3. A heated metal material is accommodated in a cylindrical container, and one end of the container is closed with a die and the other end is closed with a disk-shaped dummy block. After being advanced, the metal material is pressed through a dummy block, and the metal material is extruded from a die hole of the die.
An enlarged diameter portion is formed on one end side of the container, and a die having a protrusion having a gap between the inner surface of the container and a thickness of a material skin layer formed on a surface layer portion of the metal material and having a thickness equal to or greater than the thickness is provided. A hot extrusion apparatus for a metal material, which is provided by fitting to a diameter portion. 4. A heat-generating metal material according to claim 3, wherein a diameter-expanding chamber for retaining the material skin layer as a shell is formed between the outer periphery of the projecting portion of the die and the inner surface of the diameter-expanding portion of the container. Extrusion processing equipment. 5. The hot extrusion apparatus for a metal material according to claim 3, wherein the die is a taper die having a surface in contact with the metal material formed in a tapered shape.