JP5047241B2 - Drawing die and metal tube manufacturing method using the same - Google Patents

Description

  The present invention relates to a drawing die used for drawing a metal tube and a method for manufacturing a metal tube using the drawing die.

  Conventionally, a drawing die having the following configuration has been proposed as a drawing die used for drawing a metal tube such as an aluminum tube or an aluminum alloy tube (hereinafter referred to as an aluminum alloy tube). For example, Patent Literature 1 describes a drawing die (drawing device in the literature) in which a nib (a die in the literature) having a machining hole at the center is fixed in a die holder (a die case in the literature). Patent Document 2 discloses a groove having an outer surface corresponding to the inner surface of the case and an inner surface corresponding to the outer surface of the chip when the nib (chip in the document) is fixed in the die holder (case in the document). A drawing die fixed via a collet with a mark is described. Since the drawn metal pipe requires dimensional accuracy, the nib is made of cemented carbide and the die holder is made of steel.

JP-A-7-195115 (Claim 1, FIG. 1) JP-A-9-57331 (Claim 1, FIG. 1)

  However, the drawing die of Patent Document 1 uses a hot fitting method or a press-fitting method in order to maintain the dimensional accuracy of the metal tube after drawing when the nib is fixed in the die holder. Therefore, once the nib is fixed in the die holder, it is difficult to remove the nib from the die holder. Thus, in the drawing die of Patent Document 1, it is necessary to replace the entire drawing die, not the nib only during maintenance. Therefore, in the drawing die of Patent Document 1, since the weight of the entire drawing die is as heavy as about 10 kg, there is a problem that the workability of the exchange work is poor and the exchange work takes a long time.

  In order to solve such a problem, the drawing die of Patent Document 2 uses a collet with a groove. Therefore, in the drawing die of Patent Document 2, it is possible to replace only the nib during maintenance, but the nib is basically fixed in the die holder via the collet, but basically after drawing. In order to maintain the dimensional accuracy of the metal tube, it is fixed by press-fitting method. Therefore, it takes a long time to remove the nibs, requiring a large force. Therefore, the drawing die of Patent Document 2 has a problem that the workability of the nib replacement work is poor and the replacement work takes a long time, like the drawing die of Patent Document 1.

  Therefore, the present invention was devised to solve such a problem, the purpose of which is to maintain the dimensional accuracy of the metal tube after the drawing process, and excellent workability of replacement work during maintenance, An object of the present invention is to provide a drawing die capable of performing a replacement operation in a short time and a method of manufacturing a metal tube using the drawing die.

  In order to solve the above-mentioned problems, a drawing die according to the present invention is a drawing die used for drawing a metal tube, which is a die holder made of an aluminum alloy, and is housed inside the die holder, and the metal tube A nib made of cemented carbide having a drawing hole for drawing and inserting, and a nib presser made of tool steel contacting the nib on the tube insertion side and the tube drawing side of the drawing hole, and the nib presser A fixing means for detachably fixing to the die holder is provided. The drawing die according to the present invention is characterized in that the fixing means is a screw.

  According to the above configuration, the nib is provided in the die holder by including the nib presser that comes into contact with the nib on the tube insertion side and the tube drawing side of the drawing hole, and the fixing means for detachably fixing the nib presser to the die holder. The nibs are not pulled out in the drawing direction during drawing. In the maintenance of the drawing die, the nib can be easily removed from the die holder by removing the fixing means, and only the nib can be replaced. As a result, the dimensional accuracy of the metal tube after the drawing process is maintained, the exchange workability at the time of maintenance is improved, and the work time is shortened. Moreover, since the weight of the whole drawing die can be reduced because the die holder is made of an aluminum alloy, handling of the drawing die during maintenance is facilitated, and workability is improved.

  The drawing die according to the present invention is a drawing die used for drawing a metal tube, and is housed in a die holder made of an aluminum alloy and a first die holder portion on the tube insertion side of the die holder. A first nib made of cemented carbide having a first drawing hole into which the metal tube is inserted and drawn, and a first nib made of tool steel that comes into contact with the first nib on the tube insertion side of the first drawing hole. A first holding means for detachably fixing the presser, the first nib presser to the first die holder part, and the first drawing hole housed in a second die holder part on the tube drawing side of the die holder. A second nib made of cemented carbide having a second drawing hole for drawing the metal tube in communication with the second nib, and a second nib made of tool steel that comes into contact with the second nib on the tube drawing side of the second drawing hole. The nib presser foot Characterized in that it comprises a second securing means for removably securing the nib pressing the second die holder. The drawing die according to the present invention further includes a spacer made of an aluminum alloy disposed between the first nib and the second nib. Furthermore, the drawing die according to the present invention is characterized in that the first fixing means and the second fixing means are screws.

According to the above configuration, the first nib presser and the second nib presser hold and fix the first nib and the second nib in the die holder, and the first nib and the second nib come out in the drawing direction during the drawing process. There is nothing. In the maintenance of the drawing die, the first nib and the second nib can be easily removed from the die holder by removing the first fixing means and the second fixing means. Nibs only can be exchanged. As a result, the dimensional accuracy of the metal tube after the drawing process is maintained, the exchange workability at the time of maintenance is improved, and the work time is shortened.
Further, since the die holder and the spacer are made of an aluminum alloy, the weight of the entire drawing die can be reduced, so that the drawing die can be easily handled during maintenance and workability is improved. Furthermore, the lubricant can be supplied to and discharged from the outer surface of the metal tube drawn by the first nib by the spacer.

The metal tube manufacturing method according to the present invention is a metal tube manufacturing method including a drawing process, wherein the drawing die is used for the drawing process.
According to the above procedure, by using the drawing die for the drawing process, the dimensional accuracy of the metal tube after the drawing process is maintained, the exchange workability at the time of maintenance is improved, and the working time is shortened.

According to the drawing die of the present invention, the dimensional accuracy of the metal tube after the drawing process is maintained, and the exchanging work at the time of maintenance is excellent, and the exchanging work can be performed in a short time. In addition, since it is possible to replace only the nibs (first nib and second nib) that are in contact with the metal pipe without replacing the entire drawing die, the maintenance cost is reduced.
According to the metal tube manufacturing method of the present invention, the dimensional accuracy of the metal tube after the drawing process is maintained, the workability of the drawing die replacement work is improved, and the work time is shortened. Productivity is improved.

It is sectional drawing of the drawing die which concerns on this invention. FIG. 2 is a side view of the drawing die of FIG. 1 on the tube insertion side. It is a side view by the side of pipe drawing of the drawing die of Drawing 1. It is a disassembled perspective view of the drawing die of FIG. It is sectional drawing of the drawing die which concerns on this invention. FIG. 6 is a side view of the drawing die of FIG. 5 on the tube insertion side. It is a side view by the side of pipe drawing of a drawing die of Drawing 5. FIG. 6 is an exploded perspective view of the drawing die of FIG. 5. It is sectional drawing of the drawing die which concerns on this invention. It is explanatory drawing showing a mode that a metal pipe is drawn using the drawing die which concerns on this invention.

<Drawing dies>
An embodiment of a drawing die according to the present invention will be described with reference to the drawings.
The drawing die is used for drawing a metal tube. Here, the drawing process is a process of reducing the outer diameter of the metal tube, or the outer diameter and the inner diameter, as will be described later, and is usually a cold working performed at room temperature.
(First embodiment)
As shown in FIGS. 1 to 3, the drawing die 1 includes a die holder 2, a nib 3, a nib presser 4, and a fixing means 7.

  The die holder 2 is made of an aluminum alloy and accommodates a nib 3 to be described later. The shape of the die holder 2 is not particularly limited, but preferably has a cylindrical shape. In addition, when the die holder 2 is made of an aluminum alloy, the drawing die 1 can be reduced in weight.

  The die holder 2 is provided with a fixing means 7 (fixing means 9 on the tube insertion side) for the below-described nib presser 4 (the nib presser 6 on the tube insertion side and the nib presser 5 on the tube extraction side). The front surface 2b and the rear surface 2a, which are surfaces fixed by the fixing means 8) on the tube drawing side, and the through-hole 2c penetrating from the front surface 2b to the rear surface 2a. And the nib 3 is accommodated in the through-hole 2c. Further, in order to maintain the dimensional accuracy of the metal tube after the drawing process, a concave portion 2g corresponding to the convex portion 6c of the nib presser 6 is formed on the front surface 2b to fix the die holder 2 and the nib presser 6 with each other. 9 prevents the displacement of the fixed position. Similarly, a concave portion 2f corresponding to the convex portion 5c of the nib presser 5 is formed on the rear surface 2a to prevent the positional deviation of the die holder 2 and the nib presser 5 from being fixed by the fixing means 8. Further, when the fixing means 7 (8, 9) is a screw, a screw hole 2e corresponding to the fixing means 9 is formed in the front surface 2b on the tube insertion side, and the fixing means 8 is connected to the rear surface 2a on the tube drawing side. A corresponding screw hole 2d is formed. The die holder 2 may have a hole 2h in order to reduce the weight.

  The nib 3 is housed in the die holder 2 (through hole 2c), and is made of a cemented carbide having a drawing hole 3a into which a metal tube (not shown) is inserted and drawn. The shape is not particularly limited, but a cylindrical shape is preferable. In addition, when the nib 3 is made of a cemented carbide, the accuracy (the outer diameter, or the outer diameter and the inner diameter) of the drawn metal tube is improved.

  The drawing hole 3a of the nib 3 includes a guide part 3b for guiding the metal tube to the center of the drawing hole 3a, and a diameter adjusting part 3c for determining the drawing shape of the metal tube (the outer diameter of the metal tube after drawing). And an escape portion 3d for preventing contact damage from occurring on the outer surface of the metal tube drawn by the diameter adjusting portion 3c. In addition, it is preferable that the cross-sectional shape parallel to each drawing direction is constituted by a straight line in the guide portion 3b and the diameter adjusting portion 3c and a curve having a predetermined radius of curvature in the escape portion 3d. Moreover, it is preferable that the guide part 3b is a taper shape diameter-expanded to the pipe insertion side, and the relief part 3d is a taper shape diameter-expanded to the pipe drawing side.

  The nib presser 4 is made of tool steel that comes into contact with the nib 3 on the tube insertion side and the tube extraction side of the extraction hole 3a. The nib presser 6 is disposed on the tube insertion side, and the nib presser is disposed on the tube extraction side. It consists of five. The shapes of the nib presser 5 and the nib presser 6 are not particularly limited, but an annular plate shape is preferable. The nib presser 4 (5, 6) is made of tool steel, whereby the strength of the drawing die 1 (die holder 2) is improved.

  The nib presser 5 has a through hole 5 a that communicates with the extraction hole 3 a (escape portion 3 d) of the nib 3. Similarly, the nib presser 6 has a through-hole 6a communicating with the extraction hole 3a (guide portion 3b). The through hole 5a preferably has a tapered shape that expands toward the tube drawing side, and the through hole 6a may have a tapered shape that expands toward the tube insertion side. Further, as described above, the nib presser 5 and the nib presser 6 correspond to the concave portion 2f and the concave portion 2g of the die holder 2 in order to prevent misalignment of fixing by the fixing means 8 and the fixing means 9 with respect to the die holder 2. It has the convex part 5c and the convex part 6c which were made. Further, the nib presser 4 (5, 6) is detachably fixed to the die holder 2 (front surface 2b, rear surface 2a) by the fixing means 7 (8, 9), and the fixing means 7 (8, 9) is a screw. Has screw holes 5b and 6b corresponding to the fixing means 7 (8, 9).

  The fixing means 7 detachably fixes the nib presser 4 to the die holder 2. The fixing means 9 detachably fixes the nib presser 6 on the tube insertion side to the front surface 2 b of the die holder 2, and the tube pulling side. The nib presser 5 includes fixing means 8 for detachably fixing the nib presser 5 to the rear surface 2 a of the die holder 2. The type of the fixing means 7 (8, 9) is not particularly limited as long as the nib pressers 5, 6 can be detachably fixed to the die holder 2, and are preferably screws in view of operability, economy and the like. Moreover, the thickness of the die holder 2 can be reduced by setting the screw installation position as an offset.

  As shown in FIGS. 1 and 4, in the drawing die 1 according to the present invention, the nib pressers 5 and 6 that come into contact with the nib 3 on the tube drawing side and the tube inserting side are attached to and detached from the die holder 2 by fixing means 8 and 9. By freely fixing, the nib 3 is housed and fixed in the die holder 2 (through hole 2c), and the nib 3 does not come out in the drawing direction during the drawing process. During maintenance of the drawing die 1, the nibs 3 can be easily removed from the die holder 2 (through hole 2c) by removing the fixing means 8, 9, and only the nibs 3 can be replaced. Become.

(Second Embodiment)
As shown in FIGS. 5 to 7, the drawing die 10 is used for drawing a metal tube. The die holder 11, the first nib 13, the first nib presser 14, the first fixing means 15, 2 nibs 23, second nibs presser 24, and second fixing means 25.

  The die holder 11 is made of an aluminum alloy, and stores the first nib 13 described later in the first die holder portion 12 on the tube insertion side, and also stores the first nib 13 described later in the second die holder portion 22 on the tube drawing side. 2 Nibs 23 are accommodated, and the shape is not particularly limited, but preferably has a cylindrical shape. In addition, when the die holder 11 is made of an aluminum alloy, the drawing die 10 (die holder 11) can be reduced in weight.

  The die holder 11 includes a front surface 12a which is a surface portion for fixing a first nib presser 14 which will be described later by a first fixing means 15 in the first die holder portion 12 on the tube insertion side, and a first nib 13 therein. Through-holes 12c. Further, in order to maintain the dimensional accuracy of the metal tube after the drawing process, a concave portion 12g corresponding to the convex portion 14c of the first nib presser 14 is formed on the front surface 12a so as to form the die holder 11 and the first nib presser 14. The positional deviation of the fixing by the fixing means 15 is prevented. Further, when the first fixing means 15 is a screw, a screw hole 12d corresponding to the first fixing means 15 is formed in the front surface 12a.

The die holder 11 communicates with the rear surface 22b, which is a surface portion for fixing the second nib presser 24, which will be described later, by the second fixing means 25 in the second die holder portion 22 on the tube drawing side, and the through hole 12c. It has a through hole 22c in which the second nib 23 is accommodated. Further, in order to maintain the dimensional accuracy of the metal tube after the drawing process, a concave portion 22e corresponding to the convex portion 24c of the second nib presser 24 is formed on the rear surface 22b, and the die holder 11 and the second nib presser 24 are formed. The positional deviation of the fixing by the fixing means 25 is prevented. Further, when the second fixing means 25 is a screw, a screw hole 22d corresponding to the second fixing means 25 is formed on the rear surface 22b.
The die holder 11 may be formed with a hole 11a on the front surface 12a and a hole 11b on the rear surface 22b in order to reduce the weight.

  The first nib 13 is housed in the through hole 12c of the first die holder portion 12, and is made of a cemented carbide having a first drawing hole 13a into which a metal tube (not shown) is inserted and drawn. is there. The shape is not particularly limited, but a cylindrical shape is preferable. In addition, when the 1st nib 13 consists of cemented carbides, the dimension (outer diameter or outer diameter and inner diameter) precision of the drawn metal pipe improves.

  The first drawing hole 13a of the first nib 13 has a guide portion 13b for guiding the metal tube to the center of the first drawing hole 13a, and a drawing shape of the metal tube (outer diameter of the metal tube after drawing). A diameter adjusting portion 13c to be determined and an escape portion 13d for preventing the occurrence of contact damage on the outer surface of the metal tube drawn by the diameter adjusting portion 13c are provided. In addition, it is preferable that the cross-sectional shape parallel to each drawing | extracting direction is comprised by the curve in which the guide part 13b and the escape part 13d have a predetermined curvature radius, and the diameter control part 13c by a straight line.

  The first nib presser 14 is made of tool steel that comes into contact with the first nib 13 on the tube insertion side of the first extraction hole 13a, and its shape is not particularly limited, but an annular plate shape is preferable. The first nib presser 14 is made of tool steel, whereby the strength of the die holder 11 is improved.

  The first nib presser 14 has a through hole 14 a that communicates with the first extraction hole 13 a (guide portion 13 b) of the first nib 13. The through hole 14a may have a tapered shape that expands in diameter toward the tube insertion side. Further, as described above, the first nib presser 14 has the convex portion 14 c corresponding to the concave portion 12 g of the die holder 11 in order to prevent the positional deviation of the fixing by the fixing means 15 with the die holder 11. Further, the first nib presser 14 is detachably fixed to the die holder 11 (front surface 12a) by the first fixing means 15, and when the first fixing means 15 is a screw, a screw corresponding to the first fixing means 15 is used. It has a hole 14b.

  The first fixing means 15 detachably fixes the first nib presser 14 to the front surface 12 a of the die holder 11. The type of the first fixing means 15 is not particularly limited as long as the first nib presser 14 can be detachably fixed to the die holder 11, and is preferably a screw in consideration of operability and economy.

  The second nib 23 is housed in the through hole 22c of the second die holder portion 22 and communicates with the first drawing hole 13a of the first die 11 to draw a metal tube (not shown). It consists of the cemented carbide which has the hole 23a. The shape is not particularly limited, but a cylindrical shape is preferable. In addition, when the 2nd nib 23 consists of cemented carbides, the dimension (outer diameter or outer diameter and inner diameter) precision of the drawn metal tube improves.

  The second drawing hole 23a of the second nib 23 includes a guide portion 23b for guiding the metal pipe drawn by the first drawing hole 13a to the center of the second drawing hole 23a, and a drawing shape (drawing) of the metal pipe. A diameter adjusting portion 23c for determining the outer diameter of the metal tube after processing) and an escape portion 23d for preventing contact damage from occurring on the outer surface of the metal tube drawn by the diameter adjusting portion 23c. In addition, it is preferable that the cross-sectional shape parallel to each drawing direction is a curve in which the guide portion 23b has a predetermined radius of curvature, and the diameter adjusting portion 23c and the relief portion 23d are constituted by straight lines.

  The second nib presser 24 is made of tool steel that comes into contact with the second nib 23 on the tube extraction side of the second extraction hole 23a, and the shape thereof is not particularly limited, but an annular plate shape is preferable. In addition, the intensity | strength of the die holder 11 improves because the 2nd nib presser 24 consists of tool steel.

  The second nib presser 24 has a through hole 24 a that communicates with the second extraction hole 23 a (the escape portion 23 d) of the second nib 23. In addition, it is preferable that the through-hole 24a is a taper shape diameter-expanded to the pipe drawing side. Further, as described above, the second nib presser 24 has the convex portion 24c corresponding to the concave portion 22e of the die holder 11 in order to prevent the positional displacement of the die holder 11 by the fixing means 25. Further, the second nib presser 24 is detachably fixed to the die holder 11 (rear surface 22b) by the second fixing means 25. When the second fixing means 25 is a screw, a screw corresponding to the second fixing means 25 is used. It has a hole 24b.

  The second fixing means 25 is for detachably fixing the second nib presser 24 to the rear surface 22 b of the die holder 11. The type of the second fixing means 25 is not particularly limited as long as the second nib presser 24 can be detachably fixed to the die holder 11, and is preferably a screw in consideration of operability, economy, and the like.

The drawing die 10 may further include a spacer 31.
The spacer 31 is disposed between the first nib 13 and the second nib 23 and is made of an aluminum alloy. The shape of the spacer 31 is not particularly limited, but an annular plate shape is preferable. In addition, when the spacer 31 is made of an aluminum alloy, the drawing die 10 can be reduced in weight.

  The spacer 31 is housed together with the first nib 13 in the through hole 12c of the first die holder portion 12, and includes a front surface 31a that is a surface portion that contacts the first nib 13 on the tube insertion side, and a tube drawing side. It has the rear surface 31b which is a surface part contact | abutted with the 2nd nib 23, and the through-hole 31c penetrated from the front surface 31a to the rear surface 31b. The spacer 31 is arranged so that the through hole 31c communicates (smoothly) with the first extraction hole 13a and the second extraction hole 23a without any step. The spacer 31 may have a groove 31d on at least one of the front surface 31a and the rear surface 31b. Since the spacer 31 has the groove portion 31d, the lubricating oil can be supplied to the outer surface of the metal pipe drawn by the first nib 13 through the groove portion 31d and the dirty lubricating oil can be discharged. As a result, it is possible to prevent the metal pipe from being stretched out or being seized on the surface due to the lack of lubricating oil. Further, the viscosity of the lubricating oil (drawing oil) can be reduced. By reducing the viscosity of the drawn oil, the cleaning performance in the subsequent process is improved, the cleaning liquid can be reduced, the production line is not soiled, and the production line is solidified with oil so that it does not malfunction. Becomes easy. When the drawing die 10 is provided with the spacer 31, the die holder 11 is formed with flow paths 12h and 12i that communicate with the through holes 12c and supply and discharge the lubricating oil.

  As shown in FIGS. 5 and 8, in the drawing die 10 according to the present invention, the first nib presser 14 that contacts the first nib 13 on the tube insertion side is detachably attached to the die holder 11 by the first fixing means 15. The second nib presser 24 that contacts with the second nib 23 on the tube drawing side is detachably fixed to the die holder 11 by the second fixing means 25. As a result, the first nib 13, the second nib 23 and the spacer 31 are housed and fixed in the die holder 11 (through hole 12c and through hole 22c), and the first nib 13 and the second nib 23 are pulled out during the drawing process. Never get out of the direction. During maintenance of the drawing die 10, the first fixing means 15 and the second fixing means 25 are removed, so that the first nib 13, the second nib 23, and the spacer 31 are removed from the die holder 11 (through hole 12c and through hole). It can be easily removed from the hole 22c), and only the first nib 13 and the second nib 23 can be replaced.

  The drawing die 10 may include a case 41 in which the die holder 11 can be stored. In this case, it is preferable to form the lubricating oil supply hole 12e and the lubricating oil discharge hole 12f in the die holder 11 (first die holder portion 12). As a result, the lubricating oil is supplied from a lubricating oil supply device (not shown) to the lubricating oil supply hole 12e of the first die holder portion 12, and the lubricating oil is applied to the outer surface of the metal tube through the groove portion 31d of the spacer 31 through the flow path 12h. The supplied lubricating oil is discharged through the lubricating oil discharge hole 12f through the groove 31d and the flow path 12i. 5 and 8, the drawing die 10 stores two nibs 13 and 23 in the die holder 11, but three or more nibs may be stored, or three via a spacer. The above nibs may be stored (not shown).

(Third embodiment)
As shown in FIG. 9, the drawing die 10 </ b> A is obtained by arranging (joining) a drawing die 1 </ b> A having the same configuration as the drawing die 1 on the tube drawing side of the drawing die 1. In the drawing die 1A, the inner diameter (outer diameter of the drawing hole) DA of the nib 3A is set smaller than the inner diameter (outer diameter of the drawing hole) D of the nib 3 of the drawing die 1. The die holder 2A, nib 3A, nib presser 5A, 6A and fixing means 8A, 9A, which are the structure of the drawing die 1A, are the die holder 2, nib 3, nib presser 5, 6 and fixing means of the drawing die 1 described above. Since it is the same as 8 and 9, description will be omitted. Although not shown, the drawing die 10 of the second embodiment may be used as the drawing die 1A. Further, although not shown, in addition to the above-described two drawn dies joined, three or more drawn dies may be joined.

<Manufacturing method of metal pipe>
The method for manufacturing a metal tube according to the present invention is a method for manufacturing a metal tube including a drawing process, wherein the drawing die is used for the drawing process.
The manufacturing method of the metal tube including the drawing process may be performed according to a conventionally known procedure. However, when an aluminum alloy tube as a metal tube is manufactured, it is preferable to manufacture according to the following procedure.

(Melting casting process)
An ingot is manufactured by melting and casting an aluminum alloy having a predetermined composition.
(Homogenization heat treatment process)
The ingot produced in the above process is subjected to heat treatment at 400 to 600 ° C.
(Extrusion process)
The ingot that has been heat-treated in the above process is extruded (hot-worked) at 450 to 500 ° C. to produce a cylindrical extruded element tube.
(Drawing process)
The extruded raw tube produced in the above process is drawn (cold working) at room temperature to obtain an aluminum alloy tube. The drawing process is performed as follows, for example.
As shown in FIG. 10, the plug 52 attached to the tip of the cored bar 51 is inserted into the extruded element tube 50. The extruded element tube 50 in which the plug 52 is inserted is inserted from the nib presser 6 side fixed to the side surface of the die holder 2 of the drawing die 1 into the drawing hole 3a of the nib 3 housed and fixed inside the die holder 2. Then, the die holder 2 is pulled out to the side of the nib presser 5 fixed to the side surface. As a result, the outer diameter and thickness of the extruded tube 50 are reduced between the nib 3 and the plug 52, and the aluminum alloy tube 53 is manufactured.
If only the outer diameter of the extruded element tube 50 is to be reduced, the drawing process is performed without using the plug 52 (core metal 51).

  In addition, in the manufacture of an aluminum alloy tube, in addition to the above procedure, a heat treatment step (for example, 180 to 200 ° C.) for performing a heat treatment before the drawing step, and the aluminum alloy tube to a predetermined length after the drawing step. A cutting step for cutting, a cleaning / drying step for cleaning and drying the aluminum alloy tube, an inspection step for inspecting the appearance of the aluminum alloy tube, and the like may be performed.

1 Pulling die 2 Die holder 3 Nib 3a Pulling hole 4, 5, 6 Nib presser 7, 8, 9 Fixing means

Claims (6)

A drawing die used for drawing a metal tube,
A die holder made of an aluminum alloy;
A nib made of cemented carbide having a drawing hole that is housed inside the die holder and into which the metal tube is inserted and drawn;
A nib presser made of tool steel in contact with the nib on the tube insertion side and the tube extraction side of the extraction hole;
A drawing die comprising: a fixing means for detachably fixing the nib presser to the die holder.   2. The drawing die according to claim 1, wherein the fixing means is a screw. A drawing die used for drawing a metal tube,
A die holder made of an aluminum alloy;
A first nib made of cemented carbide having a first drawing hole that is housed in a first die holder portion on the tube insertion side of the die holder and has the metal tube inserted and drawn;
A first nib presser made of tool steel that comes into contact with the first nib on the tube insertion side of the first extraction hole;
First fixing means for detachably fixing the first nib presser to the first die holder part;
A second nib made of cemented carbide having a second drawing hole that is housed in a second die holder portion on the pipe drawing side of the die holder and communicates with the first drawing hole to draw the metal tube;
A second nib presser made of tool steel that contacts the second nib on the tube drawing side of the second drawing hole;
A drawing die comprising: a second fixing means for detachably fixing the second nib presser to the second die holder portion.   4. The drawing die according to claim 3, further comprising a spacer made of an aluminum alloy disposed between the first nib and the second nib.   The drawing die according to claim 3 or 4, wherein the first fixing means and the second fixing means are screws. A method of manufacturing a metal tube including drawing,
A metal tube manufacturing method using the drawing die according to any one of claims 1 to 5 in the drawing process.

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