Double-outlet step die for extruding high-strength aluminum alloy thin-wall profile

Abstract

The invention belongs to the technical field of hot extrusion die manufacturing, and discloses a double-outlet stepped die for extruding a high-strength aluminum alloy thin-wall profile, the double-outlet stepped die comprises an upper die and a lower die which are matched with each other, a feeding side of the upper die is provided with a feeding port, the feeding port comprises a central shunting hole and outer side shunting holes, the outer edge part of each outer side shunting hole is provided with a trapezoidal groove, and the outer side of each trapezoidal groove is provided with a through hole; the outer side flow dividing holes are divided through auxiliary flow dividing bridges, the bridge positions of the auxiliary flow dividing bridges are lower than the feeding end face of the upper die, main flow dividing bridges are arranged on the left side and the right side of the center flow dividing hole, the bridge positions of the main flow dividing bridges are lower than the bridge positions of the auxiliary flow dividing bridges, and the discharging ends of the two main flow dividing bridges are connected with die cores. Two welding chambers are arranged at the positions, corresponding to the upper welding parts, of the feeding side of the lower die, the lower die is provided with two discharging ports, and the work heads of the two die cores penetrate through the corresponding upper welding parts and the corresponding welding chambers respectively and then are inserted into the discharging ports by partial depths. The invention can reduce mold blockage, improve production efficiency, reduce mold stress and prolong the service life of the mold.

Description

Technical Field

[0001] The invention belongs to the technical field of hot extrusion die manufacturing, and specifically discloses a double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles. Background Art

[0002] In the production process of aluminum alloy profiles, 7 series aluminum alloy is widely used due to its excellent performance. However, the existing 7 series aluminum alloy extrusion die has many problems in actual production, which seriously affects the production efficiency and product quality. Specifically, the breakthrough pressure of 7 series aluminum alloy is relatively large during extrusion, which not only increases the production energy consumption, but also easily leads to equipment failure. At the same time, the mold is prone to mold blocking during the extrusion process, which causes frequent interruptions in the production process and greatly reduces the production efficiency. In addition, poor welding problems are also relatively common, affecting the overall performance and appearance quality of the extruded products. Moreover, the service life of the existing mold is low, and it needs to be replaced frequently, which increases the production cost. Taking 7004 aluminum alloy as an example, when extruding thin-walled hollow products, it usually uses a bridge tongue die. Although this die reduces the required extrusion force and increases the extrusion speed to a certain extent, it still has obvious defects. The extrusion residue is long, which not only causes material waste, but also increases the difficulty of subsequent processing. More importantly, ordinary bridge tongue dies cannot achieve continuous extrusion, and it is difficult to further improve production efficiency. In addition, most traditional aluminum extrusion dies adopt a single-outlet mode. When designing the diversion hole at the feed end, the feed area is greatly limited, which leads to the inability to effectively control the friction and the pressure in the cavity, resulting in a series of inherent defects, such as the extruded product is not formed and the product quality is unstable. In summary, the existing 7 series aluminum alloy extrusion dies have many problems in terms of breakthrough pressure, die blocking, poor welding, production efficiency and die service life. These problems seriously restrict the efficient production and high-quality manufacturing of 7 series aluminum alloy profiles. In view of the above problems, it is necessary to study and design a new type of double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles to overcome the problems existing in the existing hot extrusion dies. Summary of the invention

[0003] The invention solves the problems of high breakthrough pressure and easy mold blockage in the existing hot extrusion mold when extruding thin-walled hollow profiles, and proposes a double-outlet stepped mold for extruding high-strength aluminum alloy thin-walled profiles.

[0004] The present invention provides a double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles, comprising an upper die and a lower die that cooperate with each other, wherein the feeding side of the upper die is provided with a feeding port, wherein the feeding port comprises a central diverter hole and an outer diverter hole, wherein the central diverter hole is arranged in the middle of the feeding side of the upper die, wherein the outer diverter holes are multiple, wherein the outer diverter holes are arranged radially outward of the central diverter hole and the multiple outer diverter holes are evenly distributed, wherein the outer edge of each outer diverter hole is provided with a trapezoidal groove, wherein the ... The material is divided by an auxiliary diverter bridge, the bridge position of the auxiliary diverter bridge is lower than the feeding end face of the upper die, main diverter bridges are arranged on both sides of the left and right sides of the central diverter hole, the bridge position of the main diverter bridge is lower than the bridge position of the auxiliary diverter bridge, the discharge ends of the two main diverter bridges are connected with mold cores, the discharge side of the upper die is provided with an upper weld, the feeding side of the lower die is provided with two welding chambers corresponding to the upper weld, the lower die is provided with two discharge ports, and the foremen of the two mold cores respectively pass through the corresponding upper welds and welding chambers and then are inserted into the depth of the discharge port.

[0005] According to some embodiments of the present application, a double-outlet stepped die is used to extrude high-strength aluminum alloy thin-walled profiles. The bridge position of the auxiliary diverter bridge is 10% of the axial length of the upper die lower than the feeding end face of the upper die. The feeding end of the auxiliary diverter bridge is an arc-shaped structure with a bulge outward in the middle. The thickness of the discharge end of the auxiliary diverter bridge gradually decreases, and the auxiliary diverter bridge divides the outer diverter holes into six.

[0006] According to some embodiments of the present application, a double-step die for extruding high-strength aluminum alloy thin-walled profiles, the trapezoidal groove is provided with a radially outward step, the axial length of the radially outward step is 80% of the axial length of the upper die, and the step connections of the trapezoidal groove are provided with rounded transitions.

[0007] According to some embodiments of the present application, a double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles, the bridge position of the main diverter bridge is 20% lower than the feeding end face of the upper die by the axial length of the upper die, and the feeding end of the main diverter bridge is an arc-shaped structure with a bulge outward in the middle.

[0008] According to some embodiments of the present application, a double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles, the feeding end of the main diverter bridge is an arc-shaped structure with a middle portion bulging outward.

[0009] According to some embodiments of the present application, a double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles, the ratio of the thickness of the main diverter bridge to the span of the two main diverter bridges is 1:1.2 to 1:1.3.

[0010] According to some embodiments of the present application, a double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles, the two outlets of the lower die are centrally symmetrically arranged.

[0011] According to some embodiments of the present application, a double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles, the two welding chambers of the lower die have the same shape and the cross-sections of the two welding chambers are both butterfly structures, and the cross-section of the feed port corresponds to the cross-sections of the two welding chambers.

[0012] According to some embodiments of the present application, a double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles, the outer contour of the welding chamber is transitioned using a fillet with a radius of 3mm to 5mm.

[0013] According to some embodiments of the present application, a double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles, the upper welding axial length is 2.8 to 3.2 times the axial length of the welding chamber.

[0014] The double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles proposed by the present invention can effectively disperse the pressure when the metal flows, significantly reduce the extrusion force inside the die, thereby effectively solving the problem of pressure holding that is easy to occur in the extrusion process of traditional molds, avoiding profile defects and mold damage caused by excessive pressure, and greatly improving the stability and reliability of the production process. At the same time, the design of the double-hole discharge increases the channel for metal flow, making the flow of metal in the mold smoother, reducing the accumulation and retention of metal inside the mold, greatly reducing the probability of mold blocking, not only reducing the production interruption caused by mold blocking, but also improving the surface quality and dimensional accuracy of the profile, ensuring the quality stability of the product. In addition, the double-hole discharge can also realize the simultaneous production of two profiles, further improving production efficiency, reducing the production cost of the product, and bringing significant economic benefits. By optimizing the structure of the mold feed end and adopting a stepped feed design, it is possible to reduce the force borne by the mold and the breakthrough pressure during extrusion, reduce the possibility of the mold bridge being squeezed and cracked, and improve the service life of the mold. Reducing the height of the lower die welding chamber effectively reduces the hydrostatic pressure of the lower die welding chamber, and at the same time reduces the breakthrough pressure during extrusion. Increasing the upper welding size can improve the welding quality of profile products while increasing the welding space, making up for the shortcoming of the small height of the lower die welding chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the main structure of a double-outlet stepped die for extruding a high-strength aluminum alloy thin-walled profile according to an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the cross-sectional structure of a double-outlet stepped die for extruding a high-strength aluminum alloy thin-walled profile according to an embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of the structure of the upper die feeding end of an embodiment of the present invention;

[0018] Figure 4 This is a schematic diagram of the structure of the upper die discharge end of an embodiment of the present invention;

[0019] Figure 5 This is a schematic diagram of the structure of the lower die feeding end of an embodiment of the present invention;

[0020] Figure 6 This is a schematic diagram of the profile structure extruded according to an embodiment of the present invention.

[0021] In the figure, 1, upper mold, 1-1, central diversion hole, 1-2, outer diversion hole, 1-3, trapezoidal groove, 1-4, auxiliary diversion bridge, 1-5, main diversion bridge, 1-6, mold core, 1-61, foreman, 1-7, upper welding, 2, lower mold, 2-1, welding chamber, 2-2, discharge port. DETAILED DESCRIPTION

[0022] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0023] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0024] This embodiment provides a double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles, such as Figure 1-5As shown, it includes an upper mold 1 and a lower mold 2 that cooperate with each other. The feeding side of the upper mold 1 is provided with a feeding port, and the feeding port includes a central diversion hole 1-1 and an outer diversion hole 1-2. The central diversion hole 1-1 is arranged in the middle of the feeding side of the upper mold 1. There are multiple outer diversion holes 1-2. The outer diversion holes 1-2 are arranged radially outside the central diversion hole and the multiple outer diversion holes 1-2 are evenly distributed. The outer edge of each outer diversion hole 1-2 is provided with a trapezoidal groove 1-3. The outer diversion holes 1-2 are divided by an auxiliary diversion bridge 1-4. The bridge position of the auxiliary diversion bridge 1-4 is lower than The upper die 1 has a main diverter bridge 1-5 on both sides of the central diverter hole 1-1. The main diverter bridge 1-5 is lower than the auxiliary diverter bridge 1-4. The discharge ends of the two main diverter bridges 1-5 are connected to the mold core 1-6. The upper die 1 has an upper weld 1-7 on the discharge side. The lower die 2 has two welding chambers 2-1 on the feeding side corresponding to the upper weld 1-7. The lower die 2 has two discharge ports 2-2. The foremen 1-61 of the two mold cores 1-6 respectively pass through the corresponding upper weld 1-7 and the welding chamber 2-1 and then insert into the depth of the discharge port 2-2. The profile extruded by this embodiment is as follows: Figure 6 shown.

[0025] As a preferred embodiment of this embodiment, specifically, Figure 3 As shown, the feed port adopts a longitudinal stepped step method, the bridge position of the auxiliary diverter bridge 1-4 is 10% lower than the feed end face of the upper mold 1 by the axial length of the upper mold 1, and the feed end of the auxiliary diverter bridge 1-4 is an arc-shaped structure with a protruding middle part outward, specifically a circular arc arch structure, which can effectively increase the amount of molten aluminum and the guiding property, and the bridge position of the main diverter bridge 1-5 is 20% lower than the feed end face of the upper mold 1 by the axial length of the upper mold 1, and the feed end of the main diverter bridge 1-5 is also an arc-shaped structure with a protruding middle part outward, specifically a circular arc arch structure, which can effectively increase the amount of molten aluminum and the guiding property. In addition, the structure at the feed inlet is to step down the main shunt bridge 1-5 in the center and the surrounding auxiliary shunt bridge 1-4, and the feed ends of the main shunt bridge 1-5 and the auxiliary shunt bridge 1-4 are both arc-shaped. This structure can pre-cut the aluminum rod so that the aluminum rod can pre-form multiple streams of fluid to enter the corresponding shunt holes. Compared with the ordinary plane combination mold, it can effectively reduce the pressure area of ​​the shunt bridge, disperse the stress, and improve the bearing capacity of the shunt bridge. At the same time, it can reduce the pressure on the mold, thereby reducing the extrusion force and the breakthrough pressure of the extruded product. At the same time, the middle main shunt bridge 1-5 is lower than the surrounding auxiliary shunt bridge 1-4, so that the main shunt bridge 1-5 can bear the extrusion force and the friction with the rod relatively late, which can effectively reduce the force borne by the middle main shunt bridge 1-5. In the case of extruding 7 series aluminum alloy, the middle bridge is very easy to be squeezed and cracked. Such a stepped structure can well reduce the possibility of failure of the middle main shunt bridge 1-5 and improve the life of the mold.

[0026] As a preferred embodiment of this embodiment, specifically, Figure 4 As shown, the thickness of the discharge end of the auxiliary diverter bridge 1-4 gradually decreases, and the auxiliary diverter bridge 1-4 divides the outer diverter hole 1-2 into six. The ratio of the thickness of the main diverter bridge 1-5 to the span of the two main diverter bridges 1-5 is 1:1.2 to 1:1.3, which optimizes the ratio of bridge thickness to bridge span and improves the anti-deformation ability of the mold. The support area of ​​the bridge pier roots of the two main diverter bridges 1-5 is increased to resist the high back pressure during the extrusion of 7 series aluminum alloy.

[0027] As a preferred embodiment of this embodiment, specifically, the conventional outer flow dividing hole 1-2 usually adopts an inclined surface with an inclination of 20°-25°, such as Figure 4 As shown, the outer edge of the outer diverter hole 1-2 in the present invention is different from the inclined surface of the outer edge of the traditional outer diverter hole 1-2. The outer edge of the outer diverter hole 1-2 in the present invention adopts the form of a trapezoidal groove 1-3. Specifically, the trapezoidal groove 1-3 is provided with a step that expands radially outward, and the axial length of the step that expands radially outward is 80% of the axial length of the upper mold 1. This can effectively increase the aluminum capacity, reduce the pressure of the cavity, and prevent damage to the mold. At the same time, the step connection of the trapezoidal groove 1-3 is provided with a rounded transition. Specifically, the radius of the rounded corner can be 3mm to 5mm, which reduces the flow dead zone and turbulence caused by the high deformation resistance of the 7 series aluminum alloy.

[0028] As a preferred embodiment of this embodiment, specifically, Figure 5 As shown, the two discharge ports 2-2 of the lower die 2 are centrally symmetrically arranged. The two welding chambers 2-1 of the lower die 2 have the same shape and the cross-sections of the two welding chambers 2-1 are both butterfly-shaped structures, and the cross-section of the inlet corresponds to the cross-sections of the two welding chambers 2-1, which are also two butterfly-shaped structures. The central diversion hole 1-1 and the outer diversion holes 1-2 of the inlet are evenly distributed with the center line of the mold as the reference to ensure that the flow of metal to the two welding chambers 2-1 is balanced, so that the extruded products are of higher quality, and the products extruded from the two discharge ports 2-2 have the same quality.

[0029] As a preferred embodiment of the present invention, specifically, the outer contour of the welding chamber 2-1 is transitioned with a fillet having a radius of 3mm to 5mm, which can reduce the flow dead zone and turbulence of the metal when it flows, and avoid the blockage of the welding chamber 2-1 caused by the increase of the flow dead zone. In the present invention, the axial length of the upper welding 1-7 is 2.8 to 3.2 times the axial length of the welding chamber 2-1. In the present embodiment, the selected extruder is 2750T, and the depth of the conventional welding chamber is 15-20cm from the profile structure and design experience. Since the present scheme extrude 7 series aluminum alloy, in order to ensure the stability and strength of the foreman, the axial length of the welding chamber 2-1 is designed to be 0.6 times the axial length of the conventional welding chamber, and the axial length of the conventional welding chamber is 20% of the axial length of the lower die. In the present invention, the axial length of the welding chamber 2-1 is set to 12% of the axial length of the lower die, and the shortened part is added to the axial length of the upper welding 1-7, which can effectively reduce the empty knife length, so that the overall strength and fusion effect of the upper die 1 are effectively improved.

[0030] The present invention also conducts simulation analysis on the overall structure, and simulates according to the set extrusion process. The overall force simulation results of the upper mold 1 after simulation show that the main diverter bridge 1-5 and the auxiliary diverter bridge 1-4 are regarded as the entire diverter bridge as a whole, and the diverter bridge is the main force-bearing part. The maximum internal stress value of the diverter bridge is 1291MP. Generally, when extruding 7 series aluminum alloy thin-walled profiles, the maximum internal stress value of the conventional diverter bridge position is basically about 1800MP, while the present invention is only 1217MP, which fully demonstrates that the stepped arc arch diverter bridge plays a positive role in dispersing the internal stress of the diverter bridge position and improving the bearing capacity. More specifically, the main diverter bridge 1-5 in the middle position is much less stressed than the surrounding auxiliary diverter bridges 1-4, and the main diverter bridge 1-5 is subjected to a force value of 564MP, which verifies that the stepped diverter bridge plays a good protective role for the middle main diverter bridge 1-5 bridge position. The simulation results of the overall force of the lower die show that the breakthrough pressure of the lower die is 138MP, which is much smaller than the 320MP of the conventional planar combination die, indicating that the stepped arc arched diverter bridge is the decisive factor in reducing the breakthrough pressure. It also verifies the correctness of the method of reducing the axial length of the lower die welding chamber 2-1 to reduce the hydrostatic pressure of the welding chamber 2-1, thereby reducing the breakthrough pressure value during extrusion. The simulation results show that the overall deformation value of the double-outlet step for extruding high-strength aluminum alloy thin-walled profiles of the present invention is ≤0.7mm, which is much smaller than the deformation value of conventional dies.

[0031] The present invention can effectively solve the problems of high breakthrough pressure, unformed extruded products, poor welding, low production efficiency and short mold service life that are easy to occur during the extrusion of thin-walled hollow profiles by arranging a stepped main diverter bridge 1-5 and a secondary diverter bridge 1-4 structure, setting the main diverter bridge 1-5 and the secondary diverter bridge 1-4 feeding sections as arc structures and reducing the axial length of the lower die welding chamber 2-1, thereby improving the extrusion yield, saving costs and effectively improving the economic benefits.

[0032] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles, characterized in that: The invention comprises an upper die (1) and a lower die (2) which cooperate with each other, wherein the feeding side of the upper die (1) is provided with a feeding port, wherein the feeding port comprises a central diversion hole (1-1) and an outer diversion hole (1-2), wherein the central diversion hole (1-1) is arranged in the middle of the feeding side of the upper die (1), wherein the outer diversion holes (1-2) are multiple, wherein the outer diversion holes (1-2) are arranged radially outside the central diversion hole and the multiple outer diversion holes (1-2) are evenly distributed, wherein the outer edge of each outer diversion hole (1-2) is provided with a trapezoidal groove (1-3), wherein the outer diversion hole (1-2) is divided by an auxiliary diversion bridge (1-4), wherein the bridge position of the auxiliary diversion bridge (1-4) is lower than that of the upper die. (1) Inlet end face, main diversion bridges (1-5) are provided on both left and right sides of the central diversion hole (1-1), the bridge position of the main diversion bridge (1-5) is lower than the bridge position of the auxiliary diversion bridge (1-4), the discharge ends of the two main diversion bridges (1-5) are connected to the mold core (1-6), the discharge side of the upper mold (1) is provided with an upper weld (1-7), the inlet side of the lower mold (2) is provided with two welding chambers (2-1) corresponding to the upper weld (1-7), the lower mold (2) is provided with two discharge ports (2-2), and the foremen (1-61) of the two mold cores (1-6) respectively pass through the corresponding upper weld (1-7) and the welding chamber (2-1) and then are inserted into the partial depth of the discharge port (2-2).

2. The double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles according to claim 1, characterized in that: The bridge position of the auxiliary diverter bridge (1-4) is 10% lower than the feeding end face of the upper die (1) by the axial length of the upper die (1); the feeding end of the auxiliary diverter bridge (1-4) is an arc-shaped structure with a protruding middle part; the thickness of the discharge end of the auxiliary diverter bridge (1-4) gradually decreases; and the auxiliary diverter bridge (1-4) divides the outer diverter hole (1-2) into six.

3. The double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles according to claim 1, characterized in that: The trapezoidal groove (1-3) is provided with a radially outwardly expanded step, the axial length of the radially outwardly expanded step is 80% of the axial length of the upper mold, and the step connection of the trapezoidal groove (1-3) is provided with a rounded transition.

4. The double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles according to claim 1, characterized in that: The bridge position of the main diverter bridge (1-5) is lower than the feeding end face of the upper die (1) by 20% of the axial length of the upper die (1), and the feeding end of the main diverter bridge (1-5) is an arc-shaped structure with a protruding middle portion.

5. The double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles according to claim 1, characterized in that: The feeding end of the main diversion bridge (1-5) is an arc-shaped structure with a middle portion bulging outwards.

6. The double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles according to claim 1, characterized in that: The ratio of the thickness of the main diverter bridge (1-5) to the span of two main diverter bridges (1-5) is 1:1.2 to 1:1.

3.

7. The double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles according to claim 1, characterized in that: The two discharge ports (2-2) of the lower mold (2) are centrally symmetrically arranged.

8. The double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles according to claim 1, characterized in that: The two welding chambers (2-1) of the lower mold (2) have the same shape and the cross-sections of the two welding chambers (2-1) are both butterfly-shaped structures, and the cross-section of the feed port corresponds to the cross-sections of the two welding chambers (2-1).

9. The double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles according to claim 1, characterized in that: The outer contour of the welding chamber (2-1) is transitioned by a rounded corner with a radius of 3mm to 5mm.

10. The double-outlet stepped die for extruding high-strength aluminum alloy thin-walled profiles according to claim 1, characterized in that: The axial length of the upper weld (1-7) is 2.8 to 3.2 times the axial length of the welding chamber.

Images