Extrusion die for extrusion forming of hard-to-deform aluminum alloy material into circular tube

Abstract

The utility model discloses an extrusion die for extrusion forming of a round pipe by a difficult-to-deform aluminum alloy material, which comprises an upper die and a lower die, a plurality of shunting holes uniformly distributed around the central axis of the upper die along the circumferential direction are arranged on the end face of the upper die far away from the lower die, and a shunting bridge is arranged between every two adjacent shunting holes. And the inner ends of the extension lines of the shunting bridges in the length direction surround the central axis of the upper die to form a regular polygon. By optimizing the arrangement form of the diversion bridges, the overall structural strength of the upper die is guaranteed, stress of all positions is relatively uniform, the inner ends of the center lines of all the diversion bridges are not concentrated and intersected at the center point of the upper die any more, and the problem that stress concentration exists at the center point of the upper die of an existing extrusion die is solved; and meanwhile, the welding quality of the aluminum alloy round pipe at the welding seam position is greatly improved, color spots or stripes are not prone to appearing on the surface of the product after anodic oxidation, and the appearance of the product is more attractive.

Description

TECHNICAL FIELD

[0001] The utility model relates to extrusion die technical field, concretely relates to a kind of extrusion die for difficult deformation aluminum alloy material extrusion forming round pipe. BACKGROUND

[0002] Some aluminum alloy materials (for example 5052 aluminum alloy) belong to extremely difficult deformation alloy material, its extrusion difficulty is very big, usually only suggests flat die extrusion solid section, or is extruded seamless pipe with perforating needle.But the demand of market forces aluminum alloy section production factory to adopt shunt die to extrude this kind of extremely difficult deformation aluminum alloy material and form aluminum alloy round pipe.

[0003] Please see Figure 4 And Figure 5 And the Chinese utility model patent with publication number CN208643706U, for the shunt die for extrusion forming round pipe, the shunt bridge of upper die is evenly distributed in the center position of upper die, that is: the inner end of the center line of all shunt bridges converges at the center point of upper die, therefore, the stress of all shunt bridges will produce stress concentration problem at the center point of upper die, prone to crack bridge and other conditions, lead to very short die life.And, metal has good flowability along extrusion direction (axial direction), that is: metal is sufficient to feed the die hole of the position opposite to shunt hole, while the position under shunt bridge needs metal to flow horizontally (circumferentially) and fill the die hole before being extruded, therefore, there is big flow rate difference between the metal of shunt hole part and under bridge part, lead to the welding performance of the finally formed aluminum alloy round pipe at weld position is poor, especially after anodic oxidation surface is prone to appear color spot or stripe, lead to product appearance is not beautiful enough.

[0004] It is urgent to solve the above problems. UTILITY MODEL CONTENTS

[0005] Therefore, the utility model provides a kind of extrusion die for difficult deformation aluminum alloy material extrusion forming round pipe.

[0006] Its technical scheme is as follows:

[0007] The first aspect of the present application relates to an extrusion die for extruding a round pipe of a difficult-to-deform aluminum alloy material, comprising an upper die and a lower die matched with the upper die, the lower die having a cavity penetrating through two end faces thereof, the cavity wall of the cavity having a lower die working band extending in a circumferential direction, the upper die having a core pin matched with the cavity, the core pin inserted into the outer circumferential surface of the cavity portion having an upper die working band corresponding to the lower die working band, the gap between the upper die working band and the lower die working band forming a die hole in a circular ring structure, the upper die having a plurality of distribution holes uniformly distributed around the central axis of the upper die in a circumferential direction on the end face of the upper die away from the lower die, each adjacent distribution hole being provided with a distribution bridge, the inner end of the extension line of each distribution bridge along the length direction forming a regular polygon around the central axis of the upper die, the number of sides of the regular polygon being the same as the number of the distribution bridges.

[0008] The above extrusion die for extruding a round pipe of a difficult-to-deform aluminum alloy material optimizes the arrangement of the distribution bridges, the intersection points of the inner ends of the center lines of any two adjacent distribution bridges being located at different positions, and each intersection point being uniformly distributed around the central axis of the upper die in a circumferential direction, which not only ensures the structural strength of the upper die as a whole and makes the stress at each position relatively uniform, but also eliminates the stress concentration at the central point of the upper die of the existing extrusion die, improves the stability of the die, and prolongs the service life of the die; in addition, the eccentric distribution bridge design extending in a non-radial direction enhances the tendency of the metal to flow in a circumferential direction, thereby reducing the difference in metal flow rate at the distribution hole portion and the bridge lower portion, increasing the pressure when the two streams of metal converge, greatly improving the welding quality of the aluminum alloy round pipe at the weld position, and at the same time, the difference in temperature rise of the metal at the bridge lower portion and the distribution hole portion is not large, so the difference in grain structure between the bridge lower weld and the non-welding area is not large, thereby making it difficult for the product to have color spots or stripes after anodic oxidation, and making the appearance of the product more beautiful.

[0009] In some embodiments, the end face of the upper die close to the lower die has an upper die support surface in a circular ring plane structure, the end face of the lower die close to the upper die has a lower die support surface matched with the upper die support surface, each distribution bridge close to the lower die has a bridge lower support surface protruding from the upper die support surface, the protrusion height of each bridge lower support surface gradually increases from the upper die support surface to the direction close to the core pin, and the end face of the lower die close to the upper die is recessed to form a primary welding chamber around the cavity, the circumferential side wall of the primary welding chamber has a lower die bridge pier protruding therefrom corresponding to each distribution bridge, and each lower die bridge pier close to the upper die has a bridge pier support surface matched with the corresponding bridge lower support surface.

[0010] In some embodiments, the bridge lower support surfaces together form a conical surface structure in space, and the pier support surfaces together form a conical surface structure in space, so that each bridge lower support surface can be conical matched with the corresponding pier support surface.

[0011] In some embodiments, the lower die piers are each formed with a converging inclined surface on the side away from the upper die, which is inclined from the outer end of the corresponding pier support surface to the direction away from the lower die central axis.

[0012] In some embodiments, the angle between the pier support surface and the lower die end surface is 25-35°, and the angle between the converging inclined surface and the lower die central axis is 15-20°.

[0013] In some embodiments, the depth of the primary welding chamber is greater than or equal to 2 times the die hole width, and less than or equal to 2.5 times the die hole width.

[0014] In some embodiments, the length of the upper die working zone is greater than or equal to the length of the lower die working zone, and the length of the lower die working zone is greater than or equal to 1.5 times the die hole width, and less than or equal to 2 times the die hole width.

[0015] In some embodiments, the lower die working zone has an entrance section and a sizing section connected in sequence in the direction away from the upper die, the sizing section is a cylindrical structure, and the entrance section is a conical surface structure gradually increasing in the direction away from the sizing section. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a sectional view of the extrusion die of the present application;

[0017] Figure 2 is a structural schematic view of one of the embodiments of the extrusion die of the present application;

[0018] Figure 3 is a structural schematic view of another embodiment of the extrusion die of the present application;

[0019] Figure 4 is a structural schematic view of one of the embodiments of the extrusion die in the prior art;

[0020] Figure 5 is a structural schematic view of another embodiment of the extrusion die in the prior art. DETAILED DESCRIPTION

[0021] The present application is further described below in conjunction with the embodiments and the drawings.

[0022] As Figures 1-3As shown in the drawings, the extrusion die for extruding a round pipe from a difficult-to-deform aluminum alloy material mainly comprises an upper die 2 and a lower die 1 matched with the upper die 2, the lower die 1 has a cavity 11 penetrating through the end faces of the two ends thereof, the upper die 2 has a core pin 21 matched with the cavity 11, the core pin 21 extends into the cavity 11, and the gap between the two constitutes a die hole A. Specifically, the cavity wall of the cavity 11 is provided with a lower die working belt 111 extending in the circumferential direction, the outer circumferential surface of the part of the core pin 21 inserted into the cavity 11 is provided with an upper die working belt 211 corresponding to the lower die working belt 111, and the gap between the upper die working belt 211 and the lower die working belt 111 constitutes a die hole A in the form of a circular ring. In the embodiment, the upper die 2 and the lower die 1 are both in the form of a cylinder, and the diameters of the two are equal.

[0023] In the embodiment, the end face of the upper die 2 away from the lower die 1 is provided with a plurality of shunt holes 22 uniformly distributed around the central axis of the upper die 2 in the circumferential direction, and a shunt bridge 23 is arranged between adjacent shunt holes 22, the inner end of the central line of each shunt bridge 23 extending in the length direction thereof encloses a regular polygon around the central axis of the upper die 2, and the number of sides of the regular polygon is the same as the number of shunt bridges 23, that is, a circle is formed with the center point of the upper die 2 as the center, and the central line of each shunt bridge 23 extending in the length direction thereof is tangent to the circle.

[0024] Please refer to Figure 2 When the shunt bridges 23 are four in total, the regular polygon enclosed by the inner ends of the central lines of the shunt bridges 23 is a square.

[0025] Please refer to Figure 3 When the shunt bridges 23 are six in total, the regular polygon enclosed by the inner ends of the central lines of the shunt bridges 23 is a regular hexagon.

[0026] Therefore, the extrusion die optimizes the arrangement form of the shunt bridges 23, the intersection points of the inner ends of the central lines of any two adjacent shunt bridges 23 are located at different positions, and the intersection points are uniformly distributed around the central axis of the upper die 1 in the circumferential direction, which not only ensures the structural strength of the upper die 1 as a whole and makes the stress at each position relatively uniform, but also eliminates the problem of stress concentration at the center point of the upper die 1 in the existing extrusion die, improves the stability of the die, and prolongs the service life of the die.

[0027] And, the eccentric type shunt bridge 23 is designed to enhance the tendency of metal flowing in the circumferential direction, thereby reducing the difference in metal flow rate between the shunt hole part and the bridge lower part, increasing the pressure when the two metal flows converge, greatly improving the welding quality of the aluminum alloy round pipe at the weld position, and the temperature difference of the metal in the bridge lower part and the metal in the shunt hole part is not large, the grain structure of the bridge weld and the grain structure of the non-welding area is not large, so that the surface of the product is not easy to appear after anodizing, and the appearance of the product is more beautiful.

[0028] The end face of the upper die 2 close to the lower die 1 has an upper die support surface 24 in the form of a circular ring plane structure, and the end face of the lower die 1 close to the upper die 2 has a lower die support surface 12 which is in close contact with the upper die support surface 24, that is, the lower die support surface 12 is also a circular ring plane structure, and the upper die support surface 24 is in close contact with the lower die support surface 12.

[0029] Please refer to Figure 1 , each shunt bridge 23 close to the lower die 1 side forms a bridge lower support surface 231 protruding from the upper die support surface 24, the protrusion height of each bridge lower support surface 231 gradually increases from the upper die support surface 24 to the direction close to the core pin 21, and the end face of the lower die 1 close to the upper die 2 is recessed to form a primary welding chamber 14 around the cavity 11, and the circumferential side wall of the primary welding chamber 14 protrudes to form a lower die bridge pier 13 corresponding to each shunt bridge 23, and each lower die bridge pier 13 close to the upper die 2 side forms a bridge pier support surface 131 which is in close contact with the corresponding bridge lower support surface 231, and each bridge pier support surface 131 is inclined to the cavity 11 from the lower die support surface 12. Therefore, each bridge lower support surface 231 is supported in close contact on the corresponding bridge pier support surface 131. By increasing the spatial multi-surface cooperation of the bridge lower support surface 231 and the bridge pier support surface 131, the reliability of the support cooperation of the upper die 2 and the lower die 1 is greatly improved, the overall strength of the mold is improved, the service life of the mold is improved, and the production cost is reduced. And, through the cooperation of the bridge lower support surface 231 and the bridge pier support surface 131, each lower die bridge pier 13 can provide reliable support for each shunt bridge 23, avoid cracks or fractures of the shunt bridge 23, further reduce the risk of mold scrap, further improve the service life of the mold, and further reduce the production cost.

[0030] Further, each bridge lower support surface 231 together constitutes a conical surface structure in space, and each bridge pier support surface 131 together constitutes a conical surface structure in space, so that each bridge lower support surface 231 can be conical surface cooperated with the corresponding bridge pier support surface 131, and the reliability of the support can be further improved, and the cracks or fractures of the shunt bridge 23 can be further avoided.

[0031] Further, the lower die bridge piers 13 are formed with inwardly inclined surfaces 132 on the sides away from the upper die 2, which are inclined away from the central axis of the lower die 1, to ensure sufficient welding space and thus ensure the welding quality.

[0032] In the embodiment, the angle between the bridge pier support surface 131 and the end surface of the lower die 1 is preferably 25-35°, and the angle between the inwardly inclined surface 132 and the central axis of the lower die 1 is preferably 15-20°.

[0033] Further, the depth of the first welding chamber 14 is greater than or equal to 2 times the width of the die hole A and less than or equal to 2.5 times the width of the die hole A, so that the depth of the first welding chamber 14 can control the final welding quality.

[0034] Further, the length of the upper die working belt 211 is greater than or equal to the length of the lower die working belt 111, and the length of the lower die working belt 111 is greater than or equal to 1.5 times the width of the die hole A and less than or equal to 2 times the width of the die hole A, so that the length of the working belt can control the final welding quality.

[0035] Further, the lower die working belt 111 has an entrance section 111a and a sizing section 111b connected in sequence away from the upper die 2, and the sizing section 111b is a cylindrical structure, and the entrance section 111a is a conical structure gradually increasing away from the sizing section 111b. In the embodiment, the angle between the entrance section 111a and the central axis of the lower die is 2°, and the small angle of the entrance section 111a is conducive to ensuring the surface quality of the extruded profile during high-speed extrusion. At the same time, the axial length of the sizing section 111b is preferably 10mm, and the axial length of the entrance section 111a is preferably 60mm, which can maximize the elimination of resistance during sizing, improve the dimensional accuracy of the profile, and more conducive to ensuring the surface quality and dimensional control of the profile during high-speed extrusion.

[0036] Please refer to Figure 1 The side surfaces of each shunt bridge 23 away from the lower die 1 are shunt bridge decks 232, which together form a conical structure in space, which can make the metal feeding more sufficient.

[0037] Finally, it should be noted that the above description is only a preferred embodiment of the present application, and those skilled in the art can make various similar expressions under the inspiration of the present application without deviating from the purpose and claims of the present application. Such changes fall within the scope of the present application.

Claims

1. An extrusion die for extruding a round pipe from a difficult-to-deform aluminum alloy material, comprising an upper die and a lower die matched with the upper die, the lower die having a cavity extending through both end faces thereof, the cavity wall of the cavity having a lower die working band extending in a circumferential direction, the upper die having a core matched with the cavity, the core having a working band corresponding to the lower die working band on the outer circumferential surface of the core inserted into the cavity, the gap between the working band of the upper die and the lower die working band forming a die hole in a circular ring structure, the upper die having a plurality of distribution holes uniformly distributed around the central axis of the upper die on the end face of the upper die away from the lower die, and a distribution bridge being arranged between adjacent distribution holes. The inner ends of the center lines of the distribution bridges along their length direction enclose a regular polygon around the center axis of the upper die, the number of sides of the regular polygon being the same as the number of the distribution bridges.

2. The extrusion die for extruding a round tube of a difficult-to-deform aluminum alloy material according to claim 1, characterized by: The end face of the upper die close to the lower die has an upper die support face in the form of a circular ring plane structure, the end face of the lower die close to the upper die has a lower die support face which is in close contact with the upper die support face, each distribution bridge close to the lower die has a bridge lower support face which protrudes from the upper die support face, the protruding height of each bridge lower support face gradually increases from the upper die support face to the direction close to the core pin, and the end face of the lower die close to the upper die is recessed to form a primary welding chamber which surrounds the cavity, the circumferential side wall of the primary welding chamber has a lower die bridge pier corresponding to each distribution bridge, and each lower die bridge pier close to the upper die has a bridge pier support face which is in close contact with the corresponding bridge lower support face.

3. The extrusion die for extruding a round tube of a difficultly deformable aluminum alloy material according to claim 2, characterized by: Each bridge lower support face and each bridge pier support face together form a conical surface structure in space, so that each bridge lower support face can be conical surface matched with the corresponding bridge pier support face.

4. The extrusion die for extruding a round tube of a difficultly deformable aluminum alloy material according to claim 3, characterized by: The side of each lower die bridge pier away from the upper die has a converging inclined surface which is inclined from the outer end of the corresponding bridge pier support face to the direction away from the center axis of the lower die.

5. The extrusion die for extruding a round tube of a difficult-to-deform aluminum alloy material according to claim 4, characterized by: The angle between the bridge pier support face and the end face of the lower die is 25°-35°, and the angle between the converging inclined surface and the center axis of the lower die is 15°-20°.

6. The extrusion die for extruding a round tube of a difficult-to-deform aluminum alloy material according to claim 2, characterized by: The depth of the primary welding chamber is greater than or equal to 2 times the die hole width and less than or equal to 2.5 times the die hole width.

7. The extrusion die for extruding a round tube of a difficult-to-deform aluminum alloy material according to claim 1, characterized by: The length of the upper die working zone is greater than or equal to the length of the lower die working zone, and the length of the lower die working zone is greater than or equal to 1.5 times the die hole width and less than or equal to 2 times the die hole width.

8. The extrusion die for extrusion molding a round pipe of a difficultly deformable aluminum alloy material according to claim 1 or 7, characterized by: The lower die working zone has an inlet section and a sizing section connected in sequence in the direction away from the upper die, the sizing section is in the form of a cylindrical structure, and the inlet section is in the form of a conical surface structure which gradually increases in the direction away from the sizing section.

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