CN202498093U - Mould for extrusion forming of tubes - Google Patents

Abstract

The utility model relates to a die used for extruding pipe material. The end face of one end of the punch is connected with one end face of the inner liner of the extrusion barrel through a connecting pin; the end face of the other end of the punch is connected with one end face of the die. During the connection, the outlets of the metal flow channels in the lining of the extrusion barrel are all connected to the inlets of the metal flow channels located on the matching end face of the punch; The welding cavity in the center, and the gap between the sizing rod and the die is the same as the wall thickness of the formed pipe. The utility model adopts the method of changing the shunt mold into multiple blanks entering the welding cavity together, each blank is independent of each other, and the equal-channel corner deformation occurs before the alloy enters the welding cavity, and the welding and extrusion are realized after entering the welding cavity It is shown that the process of shunting the alloy is effectively avoided, and because the extrusion force concentrates on the equal channel corners to refine the grains and the welding process, the welding quality is better, and the product grains are fine, so that better extrusion products can be obtained.

Description

A mold for pipe extrusion

technical field

The invention relates to the field of thermal processing, in particular to a forming die for obtaining fine-grained magnesium alloy pipes through multi-blank equal-channel corner welding and extrusion forming.

technical background

Lightweight alloy pipes such as fine-grained magnesium alloy and aluminum alloy have the advantages of light weight, high specific strength and specific stiffness. It is very attractive in the fields of aviation, aerospace, bicycles, portable signal towers, etc. However, the traditional process of making such light alloy pipes mostly adopts split extrusion, which requires a large extrusion force, and it is often difficult to accurately control the extrusion process parameters, which often leads to mold cracking and other phenomena in the pipe. This is all related to the fact that both the shunting process and the welding process consume a lot of extrusion force. Moreover, the alloy pipe extruded by the traditional split extrusion method often needs to be extruded by heating the alloy to a very high temperature in order to reduce the extrusion force, so the extruded pipe has coarse grains, poor mechanical properties, serious surface oxidation, The precision of the pipe is difficult to meet the requirements of use.

Equal-diameter angular extrusion, also called equal-channel angular extrusion, referred to as ECAE or ECAP, this technology is an advanced technology for obtaining ultra-fine-grained materials. Billet extrusion, through the action of corners, causes a large shear strain of the metal material during the extrusion process to achieve the purpose of refining grains and improving performance. This technology is often mentioned in the literature, but there is no literature or invention to use this technology. In actual products, it is generally used to refine the grains of various bar blanks. For example, the authors Z.J.Zhang and I.H.Son described the technology to produce The mechanism and process of refining metal grains, etc. Another example is the author M.W.Fu a and Y.W.Tham in the document "The grain refinement of Al-6061 via ECAE processing: Deformation behavior, microstructure and property" described the grain refinement and performance improvement of 6061 aluminum alloy after deformation by ECAE .

In the invention with the publication number CN2690068, a device for preparing ultra-fine crystal tube material is disclosed by equal channel angular extrusion. The invention utilizes a hollow extruding rod to carry out a multi-pass equal-channel angular extrusion process on the pipe to refine the crystal grains of the pipe. The advantage is that the size of the pipe remains unchanged during the whole process, and each part undergoes equal-channel corner deformation under the action of the mold. The disadvantage is that the blank must be a processed pipe, and this invention can only refine the grain of the existing pipe to improve performance, rather than manufacture the pipe.

In the invention with the publication number CN102189143A, a method for preparing an ultrafine-grained nickel-titanium shape memory alloy tube based on equal radial extrusion is disclosed. In this invention, a metal core is inserted into the inside of the nickel-titanium shape memory alloy tube blank to be formed, and then the nickel-titanium shape memory alloy tube blank is sealed in the metal sleeve, and the metal sleeve is fixed in the ECAE tooling composed of the punch and the die. The nickel-titanium shape memory alloy tube blank and the metal core are simultaneously extruded to produce shear plastic deformation, so as to realize the grain refinement of the nickel-titanium shape memory alloy tube blank. The disadvantage of this invention is that the deformation process has auxiliary materials (such as sleeve and mandrel) to participate in the deformation, after extrusion, the sleeve deformed together with the product is peeled off, and the mandrel deformed together with the product is taken out, which not only increases Subsequent processing of the product also increases energy consumption due to the participation of auxiliary materials in deformation.

In view of this, the present invention provides a high-precision, high-strength, fine-grained, thin-walled alloy pipe by improving the extrusion cylinder and the mold, realizing multi-blanks and other channel corners to refine the grains, and then welding and extrusion forming, which not only avoids the shunting process The extrusion force is dissipated, and the use of equal channel corners achieves a better effect of refining grains and improving performance.

Contents of the invention

In order to overcome the disadvantages of increasing subsequent processing steps and energy consumption in the forming process in the prior art, the present invention proposes a die for extrusion forming of pipes.

The invention comprises an extrusion barrel liner, a punch and a die; the end face at one end of the punch is connected to one end face of the extrusion barrel liner through a connecting pin; the other end face of the punch is connected to one end face of the die; , the outlets of the four metal flow channels in the lining of the extrusion cylinder are all connected to the inlets of the four metal flow channels located on the mating end face of the punch; the sizing rod located at the center of the mating end face of the punch and the die is embedded in the center of the die There is a gap between the sizing rod and the inner surface of the sizing hole on the die; the size of the gap is the same as the wall thickness of the formed pipe.

There are 4 to 6 metal flow passages extending along the axial direction of the extrusion cylinder lining and passing through the extrusion cylinder lining evenly distributed in the inner lining of the extrusion cylinder; The centerlines of the inner lining of the press cylinder are parallel, and the centerlines of the blank holes are equidistant from the centerline of the inner lining of the extrusion cylinder.

The sizing rod is located at the center of the end face of the punch and the die; the end of the sizing rod has a radially protruding boss whose diameter is equal to the inner diameter of the pipe to be formed; There are 4 metal flow channels running through the axial direction of the punch evenly distributed on the top, and the center line of each metal flow channel has an included angle of 15 to 50° with the center line of the punch. The corner of the metal flow channel is formed on the mating surface of the die; the outlet of the metal flow channel of the punch on the mating end face of the punch and the die is tangent to the root of the sizing rod located on the end face of the punch 4 .

The inner hole at one end of the mating die and the punch is an equal-diameter hole, and the other end of the die is a forming hole, and the die opening of the forming hole is larger than the die opening of the forming hole; the mating end of the die and the punch is There is a welding cavity in the center of the end face, and the aperture of the welding cavity is slightly larger than the distance between the outer edges of each metal flow channel on the end face of the punch; there is a fixed diameter hole between the welding cavity of the die and the variable diameter hole of the die; The inner diameter of the sizing hole is 15-100mm.

The aperture at the end face of the mating die and the punch 4 is 3mm larger than the outer edge of each metal flow channel on the end face of the punch.

In the present invention, by changing the diverting die into a method in which multiple blanks enter the welding cavity together, each blank is independent of each other, replacing several metal streams after the traditional extrusion method is divided, and equal passage occurs before the alloy enters the welding cavity Corner deformation, welding extrusion after entering the welding cavity. Not only effectively avoids the process of shunting the alloy, but also the extrusion force provided by the extruder is almost all concentrated on the equal channel corner to refine the grain and the welding process, so that the welding quality is better, the product grain is finer, and thus better extruded product. In the present invention, there is an included angle between the centerline of the metal flow channel on the punch and the centerline of the mold, so that the metal passes through the extrusion cylinder liner and the punch to produce equal passage angle deformation during flow, that is, the crystal can be refined. Pure shear deformation of grains. The inner diameter of the extruded product pipe is determined by an axially protruding sizing rod located at the center of one end of the punch. The welding cavity on the die 7 adopts circular arc smooth transition everywhere, so as to avoid dead zone in the process of metal flow deformation.

During use, the metal billet in the inner lining of the extrusion barrel flows to the punch under the push of the extrusion pad, and plastic deformation occurs at the corner of the channel at the junction of the punch and the die, and the plastic deformation occurs at the corner of the channel at the junction of the punch and the die. Flow to the welding cavity area, and extrude through the sizing rod to determine the cross-sectional shape of the pipe. There are three plastic deformation stages in the process of grain refinement in this process. The first stage is that the channel corner process causes a large shear plastic deformation of the metal during the flow process, so the grains can be refined. The second stage is the plastic deformation of the metal during the welding process, and the atomic slip and twinning during the filling process under high pressure can refine the grains. The third stage is the simple extrusion deformation in which the extrusion section becomes smaller when the metal is extruded from the working belt, which can refine the grains. The larger the extrusion ratio, the better the refinement effect. For example, using 4 billets with a diameter of 34mm to extrude an AZ31 magnesium alloy pipe with a diameter of 104mm and a thickness of 3mm, the grain size of the original billet is more than 100 μm, and the average grain size is finally obtained below 8 μm.

Compared with the traditional single-billet shunting extrusion welding pipe process, the present invention can avoid the increase of the extrusion force caused by the single billet in the process of splitting into multiple metal streams by using multiple billets, so the die described in the present invention can reduce the Small extrusion force, such as using 4 billets with a diameter of 34mm to extrude an AZ31 magnesium alloy pipe with a diameter of 104mm and a thickness of 3mm, the peak extrusion force is 210 tons. Compared with the 630 tons of the traditional process, the labor saving is more than 50%. And the present invention adopts the split-type combined mold, which is simple and convenient to operate.

Description of drawings

Accompanying drawing 1 is the assembly drawing of multi-blank equal-channel corner welding extruded pipe mold; wherein: Fig. 1a is a right view; Fig. 1b is a main sectional view; Fig. 1c is an A-A sectional view;

Accompanying drawing 2 is the liner of extruding cylinder; Wherein: Fig. 2a is a right side view; Fig. 2b is a main sectional view; Fig. 2c is a B-B sectional view;

Accompanying drawing 3 is punch; Wherein: Fig. 3a is a right view; Fig. 3b is a main sectional view; Fig. 3c is a left view; Fig. 3d is a C-C sectional view;

Accompanying drawing 4 is a concave mold; Wherein: Fig. 4a is a right view; Fig. 4b is a main sectional view; Fig. 4c is a D-D sectional view;

Accompanying drawing 5 is a schematic diagram of the flow process of metal in the mould. in:

1. Blank hole 2. Positioning groove 3. Extrusion barrel lining 4. Punch 5. Lifting screw hole 6. Connecting pin

7. Die 8. Positioning pin 9. Connecting hole 10. Positioning pin hole 11. Bolt

12. Connecting pin 13. Welding cavity 14 Connecting hole 15. Lifting screw hole 16. Sizing rod

17. Bolt hole 18. Squeeze pad 19 Blank 20. Corner of equal channel 21. Channel 22. Sizing hole

Detailed ways

This embodiment is a die for forming fine-grained alloy pipes by corner welding and extruding fine-grained alloy pipes with multiple blanks and equal channels, which is used for extrusion-forming fine-grained magnesium alloy pipes. The extruded pipe product has a diameter of 104 mm and a thickness of 3 mm round pipe. The tonnage of the extruder used in the forming process is 2500t. The mold and other extrusion tools are made of H13 hot work die steel.

This embodiment includes an extrusion cylinder liner 3 , a punch 4 and a die 7 . The end surface of one end of the punch 4 is connected with an end surface of the extrusion barrel lining 3 through a connecting pin 12; During the connection, the outlets of the four metal flow channels in the extrusion cylinder liner 3 are all connected to the inlets of the four metal flow channels located on the mating end face of the punch 4; The diameter rod is embedded in the welding cavity 13 at the center of the die 7 .

As shown in accompanying drawing 2, the liner 3 of the extrusion cylinder is a cylinder. The outer diameter of the extrusion cylinder liner 3 is matched with the inner diameter of the extrusion cylinder. There are four straight holes extending along the axial direction of the extrusion cylinder lining 3 and passing through the extrusion cylinder lining 3 evenly distributed in the extrusion cylinder lining 3, and the straight holes are all metal flow channels. The diameter of the metal flow channel is determined according to the outer diameter of the billet to be formed. The centerlines of the metal flow passages are all parallel to the centerline of the extrusion barrel lining 3, and the centerlines of each blank hole are equidistant from the centerline of the extrusion barrel lining 3. There is an annular positioning groove 2 with a rectangular cross-section in the middle of the outer peripheral surface of the extrusion cylinder lining 3. When the extrusion cylinder lining 3 is matched with the extrusion cylinder, the snap ring on the inner surface of the extrusion cylinder passes through the positioning groove 2. The cooperation realizes the axial positioning of the extrusion cylinder liner 3. Two connection holes are symmetrically distributed on the end surface of the extrusion cylinder liner 3 and the punch 4 , which are used to securely connect the extrusion cylinder liner 3 and the punch 4 .

As shown in accompanying drawing 3, there is an axially protruding cylindrical sizing rod 16 in the center of the end face of the male die 4 that is mated with the female die 7 . There is a radially protruding boss at the end of the sizing rod 16. The diameter of the boss is equal to the inner diameter of the pipe to be formed, so that the longitudinal section of the sizing rod is "T"-shaped to facilitate metal forming. In this embodiment, the diameter at the end of the sizing rod is 8 mm larger than that of other parts of the sizing rod, and the axial length at the end of the sizing rod is 8 mm. The axial length of the sizing belt is 15-100 mm, and in this embodiment, the length of the sizing rod is 20 mm. When the punch 4 is matched with the die 7, the end of the sizing rod 16 located on the end face of the punch 4 is embedded in the sizing hole of the die, and there is a gap between the inner surface of the sizing hole on the die 7 ; The size of the gap is the same as the wall thickness of the formed pipe.

On the punch 4, there are 4 through holes passing through the metal flow channel in the axial direction of the punch 4, and the metal flow channel on the punch 4 is at the mating end of the punch 4 and the inner liner 3 of the extrusion cylinder. The distance L between the hole of the end face and the center line of the mold is greater than the distance l between the hole of the end face of the punch 4 and the die 7 and the center line of the mold, so that the center lines of each metal flow channel are aligned with the center line of the punch 4 There is an included angle of 15 to 50° between the centerlines, and the corner of the metal flow channel is formed on the mating surface of the extrusion cylinder liner 3 and the punch 4, so that the metal passes through the extrusion cylinder liner and the convex die during the flow. The die undergoes equal-channel angular deformation, that is, pure shear deformation that can refine the crystal grains; in this embodiment, the angle between the centerline of each through hole and the centerline of the punch 4 is 17°. The outlet of the metal flow channel of the punch 4 on the end face of the punch 4 mated with the die is tangent to the root of the sizing rod 16 located on the end face of the punch 4 .

On the two ends of the male die 4, there are two pin holes evenly distributed on each, respectively for the axial positioning and connection of the male die 4, the extrusion cylinder liner 3 and the die 7. The outer surface of punch 4 has a threaded hole 5 for lifting. There are two threaded blind holes on the end face of the mating end of the punch 4 and the die 7, which are used to fasten the punch and the die.

As shown in Figure 4, the concave mold 7 is a hollow rotating body, and its inner hole is stepped, and the inner hole at one end of the concave mold 7 and the convex mold 4 is an equal-diameter hole, and the other end of the concave mold 7 is a variable diameter hole. A forming hole with a diameter of 100 mm is formed at the end of the die 7 to form a bell mouth, so that the die outlet of the forming hole is larger than the inlet of the forming hole, so as to reduce the friction between the formed pipe and the forming hole wall. In this embodiment, the angle between the hole wall of the forming hole and the centerline of the mold is 13°. There is an annular boss on the outer edge of the end surface of the mating end of the female die 7 and the male die 4 for radial positioning of the male die 4 . The inner diameter of the annular boss is the same as the outer diameter of the annular assembly step on the matching end face of the punch 4 . There is a welding cavity 13 in the center of one end face of the concave die 7 and the punch 4, and the aperture of the welding cavity 13 is slightly larger than the distance from the outer edge of each metal flow channel on the end face of the punch 4, so as to facilitate metal filling and flow. In this embodiment, the hole diameter at the end face of the mating die 7 and the punch 4 is 3 mm larger than the outer edge of each metal flow channel on the end face of the punch 4 .

Between the welding cavity 13 of the die 7 and the variable diameter hole of the die 7, there is a sizing hole 22 of equal diameter. The inner diameter of the sizing hole 22 is the same as the outer diameter of the formed pipe. The axial length of the sizing hole 22 is determined according to the specifications of the formed pipe, and is 15-100 mm; Same, also 8mm. There are lifting screw holes 15 and positioning pin holes 10 on the outer surface of the die 7 .

The right angle at the bottom of the welding cavity 13 adopts a smooth transition of an arc of R=10mm, so as to avoid dead zones during metal flow deformation.

There are 2 positioning pin holes on the end face where the die 7 and the punch 4 cooperate. Misalignment between. There are two bolt through holes 17 on the end face of the die 7, which are used to connect the die 7 to the punch 4 by bolts.

During assembly, the extrusion cylinder liner 3 and the punch 4 are axially positioned using the connecting pin 12 and the positioning hole 9, and the positioning groove 2 is used to fix the position of the extrusion cylinder liner 3 along the axis. The punch 4 and the die 7 are fixed by the positioning pin 6 and the inner hexagon bolt; the lifting screw hole 5 is used to assemble and install the mold on the extrusion machine; the positioning pin 8 and the positioning hole 10 cooperate to make the mold Circumferential positioning, the positioning pin 8 is Φ16×40mm. The positioning groove 2 is used to determine the axial position of the extrusion cylinder liner, and should coordinate with the extrusion cylinder for axial positioning. After assembly, brush graphite water on the inner wall of the blank hole 1 and the inner wall of the mold for lubrication.

Claims (5)

1. a mould that is used for the tubing extrusion molding is characterized in that, comprises recipient liner, punch and die; The end face of punch one end is connected with an end face of recipient liner through connecting pin; The end face of the punch other end is connected with an end face of die; In the connection, the outlet of four strip metal flow channels in the recipient liner is all docked with the inlet of four metal flow passages that are positioned at punch abutting end end face; The fixed diameter rod that is positioned at punch and die abutting end end face center embeds the seam chamber at die center, and gapped between the metering hole inner surface on fixed diameter rod and the die; The size in said gap is identical with the wall thickness of formed thereby tubing.

2. a kind of according to claim 1 mould that is used for the tubing extrusion molding is characterized in that, is evenly equipped with 4 in the recipient liner and extends and connect the axial metal flow passage of this recipient liner along recipient liner axial direction; The center line of said each metal flow passage is all parallel with the center line of recipient liner, and the center line equidistance of the center line in each blank hole and recipient liner.

3. a kind of according to claim 1 mould that is used for the tubing extrusion molding is characterized in that, described fixed diameter rod is positioned on the punch end face center that cooperates an end with die; There is the radially boss of protrusion this fixed diameter rod end, and the diameter of this boss equals the internal diameter of tubing to be formed; On punch, be evenly equipped with 4 and connect the axial metal flow passages of this punch, the center line of each metal flow passage all and 15～50 ° angle is arranged, the corner of formation metal flow passage on the mating surface of recipient liner and punch between the center line of punch; The metal flow passage of said punch cooperates the outlet on the end end face at this punch with die, tangent with the root of the fixed diameter rod that is positioned at punch 4 these end faces.

4. a kind of according to claim 1 mould that is used for the tubing extrusion molding is characterized in that, said die cooperates the endoporus of an end with punch be isometrical hole, and this die other end is a shaped hole, and this shaped hole go out the go into die orifice of die orifice greater than this shaped hole; Die cooperates an end end face center that the seam chamber is arranged with punch, the aperture in this seam chamber is slightly larger than the distance of each the metal flow passage outer rim on the punch end face; Between the reducing hole of the seam chamber of die and die, metering hole is arranged; The internal diameter of this metering hole is 15～100mm.

5. require 1 said a kind of mould that is used for the tubing extrusion molding like profit, it is characterized in that, said die cooperates aperture, an end end than the big 3mm of each metal flow passage outer rim on the punch end face with punch 4.

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