Reciprocating upsetting-extruding device and method for aluminum-lithium alloy grain refinement

Abstract

The invention relates to the technical field of aluminum alloy deformation machining, and discloses a reciprocating upsetting-extruding device and method for aluminum lithium alloy grain refinement, the reciprocating upsetting-extruding device comprises a die body, the die body is placed on a hydraulic machine, the die body comprises an upper die and a lower die, and the upper die is installed at the top end of the lower die through a bolt; an upsetting-extruding cavity is formed in the die body, an upper ejector rod, a lower ejector rod and a sample are arranged in the upsetting-extruding cavity, and the sample is located between the upper ejector rod and the lower ejector rod and is upset-extruded repeatedly through the upper ejector rod and the lower ejector rod. According to the method, grain refinement of the aluminum alloy bar is achieved, and the structure uniformity and obdurability of the aluminum alloy are effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy deformation processing, and in particular to a reciprocating upsetting device and method for grain refinement of aluminum-lithium alloy. Background Art

[0002] As a lightweight and high-strength structural material, aluminum-lithium alloy is widely used in aerospace and other fields. With the rapid development of the aerospace field in recent years, higher requirements have been put forward for the strength and toughness of aluminum-lithium alloy. The microstructure of aluminum-lithium alloy determines its mechanical properties. Therefore, by refining the grains to improve the microstructure of aluminum-lithium alloy, its comprehensive performance can be effectively improved in combination with an effective heat treatment process. At present, the methods for grain refinement of aluminum-lithium alloy include adding grain refiners, rapid solidification, large plastic deformation, thermomechanical treatment, etc., among which large plastic deformation is the most effective method for grain refinement. The methods for grain refinement of aluminum-lithium alloy by large deformation mainly include equal-diameter angular extrusion, high-pressure torsion, stir friction processing, cumulative rolling, etc. Although they can significantly refine the grains and improve the strength and plastic toughness of aluminum-lithium alloy, they usually have high requirements for equipment, high cost and complex process. The reciprocating upsetting process was first used to mechanically alloy the powder in the mold by repeated loading, and then it was applied to the deformation processing of metal materials. The reciprocating upsetting process has a simple mold, low cost and easy operation.

[0003] Therefore, there is an urgent need for a reciprocating upsetting device and method for refining the grains of aluminum-lithium alloy to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a reciprocating upsetting device and method for grain refinement of aluminum-lithium alloy to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above object, the present invention provides the following solution: The present invention provides a reciprocating upsetting device for grain refinement of aluminum-lithium alloy, comprising a die body, wherein the die body is placed on a hydraulic press,

[0006] The mold body comprises an upper mold and a lower mold, and the upper mold is mounted on the top of the lower mold by bolts;

[0007] An upsetting cavity is provided in the mold body, an upper ejector rod, a lower ejector rod and a sample are arranged in the upsetting cavity, the sample is located between the upper ejector rod and the lower ejector rod, and is repeatedly upset by the upper ejector rod and the lower ejector rod.

[0008] Preferably, the upsetting cavity comprises an upper cavity and a lower cavity, the upper cavity is arranged in the upper mold, the lower cavity is arranged in the lower mold, and opposite ends of the upper cavity and the lower cavity form an intermediate cavity.

[0009] Preferably, the diameters of the upper cavity and the lower cavity are smaller than the diameter of the middle cavity.

[0010] Preferably, a gasket is provided between the sample and the upper push rod and the lower push rod.

[0011] A reciprocating upsetting method for grain refinement of aluminum-lithium alloy comprises the following steps:

[0012] S1, heating the mold body and the sample;

[0013] S2, placing the lower ejector rod, the heated sample and the upper ejector rod into the upsetting cavity in sequence, and squeezing them downwards through the upper ejector rod;

[0014] S3, after the extrusion is completed, the mold body is turned over, and the upper ejector rod is placed on the upper side to extrude the sample;

[0015] S4. Repeat step S3 to achieve grain refinement.

[0016] Preferably, in S2, the upper ejector rod squeezes the sample to cause the sample to undergo upsetting deformation until the middle cavity is filled, and after the cavity is filled, the lower ejector rod is removed to allow the upper ejector rod to continue extruding, so that the sample undergoes upsetting and extrusion deformation simultaneously.

[0017] Preferably, in S3, the mold body is flipped 180°.

[0018] Preferably, when the top end of the sample is located at the upper end of the middle cavity, the extrusion is stopped and the mold body is turned over.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects:

[0020] The present invention provides a reciprocating upsetting device and method for grain refinement of aluminum-lithium alloy. The device places a sample in an upsetting cavity, realizes upsetting deformation and extrusion deformation of the sample by an upper ejector rod and a lower ejector rod, and firstly upsets the sample and then extrudes it, and repeats the process repeatedly. An ultra-high degree of grain refinement of 100 μm to 5 μm is realized through multiple passes, and the grain refinement of aluminum alloy bars is realized, thereby effectively improving the organizational uniformity and toughness of the aluminum alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor:

[0022] Figure 1This is a schematic diagram of the mold body structure of the present invention;

[0023] Figure 2 It is a schematic diagram of the structure of the upsetting cavity of the present invention;

[0024] Figure 3 It is a schematic diagram of the reciprocating upsetting process of the present invention;

[0025] Figure 4 This is a comparison diagram of the grain size after different upsetting passes of the device of the present invention;

[0026] Among them, 1. upper ejector pin; 2. upper mold; 3. test specimen; 4. gasket; 5. lower mold; 6. lower ejector pin; 7. upper cavity; 8. lower cavity; 9. middle cavity. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Reference Figure 1-Figure 4 The present invention provides a reciprocating upsetting device for grain refinement of aluminum-lithium alloy, comprising a die body, the die body being placed on a hydraulic press,

[0030] The mold body includes an upper mold 2 and a lower mold 5, and the upper mold 2 is mounted on the top of the lower mold 5 by bolts;

[0031] An upsetting cavity is provided in the mold body, in which an upper ejector pin 1, a lower ejector pin 6 and a sample 3 are arranged. The sample 3 is located between the upper ejector pin 1 and the lower ejector pin 6 and is repeatedly upset by the upper ejector pin 1 and the lower ejector pin 6.

[0032] According to a further optimization scheme, the upsetting cavity includes an upper cavity 7 and a lower cavity 8. The upper cavity 7 is arranged in the upper mold 2, and the lower cavity 8 is arranged in the lower mold 5. The opposite ends of the upper cavity 7 and the lower cavity 8 form an intermediate cavity 9.

[0033] According to a further optimization scheme, the diameters of the upper cavity 7 and the lower cavity 8 are smaller than the diameter of the middle cavity 9.

[0034] In one embodiment of the present invention, the diameters of the upper cavity 7 and the lower cavity 8 are smaller than the middle cavity 9, thereby ensuring that the sample 3 can be upset and extruded.

[0035] To further optimize the solution, a gasket 4 is provided between the sample 3 and the upper push rod 1 and the lower push rod 6 .

[0036] In one embodiment of the present invention, in order to ensure the extrusion effect, a gasket 4 is provided between the sample 3 and the upper ejector rod 1 and the lower ejector rod 6 .

[0037] A reciprocating upsetting method for grain refinement of aluminum-lithium alloy comprises the following steps:

[0038] S1, heating the mold body and the sample 3;

[0039] The reciprocating upsetting is carried out on a hydraulic press. The die body and the sample are heated to 350°C before deformation, and lubricant is evenly applied to the upsetting cavity in the die body for lubrication.

[0040] S2, placing the lower ejector pin 6, the heated sample 3 and the upper ejector pin 1 into the upsetting cavity in sequence, and extruding them downwards through the upper ejector pin 1;

[0041] S3, after the extrusion is completed, the mold body is turned over, and the upper ejector rod 1 is placed on the top to extrude the sample 3;

[0042] S4. Repeat step S3 to achieve grain refinement.

[0043] According to a further optimization scheme, the upper ejector rod 1 in S2 squeezes the sample 3 to cause the sample 3 to undergo upsetting deformation until the middle cavity 9 is filled. After the cavity 9 is filled, the lower ejector rod 6 is removed to allow the upper ejector rod 1 to continue extruding, so that the sample 3 undergoes upsetting and extrusion deformation at the same time.

[0044] In one embodiment of the present invention, the lower push rod 6 is placed in a fixed position, the gasket 4 and the heated sample 3 are placed in the upsetting cavity, and the upper push rod 1 moves downward under the action of the hydraulic press to cause the sample to be upset and deformed until the sample fills the intermediate cavity 9, and the lower push rod 6 is removed, and the upper push rod 1 continues to move downward under the action of the hydraulic press, causing the sample 3 to be upset and extruded at the same time, until the upper push rod 1 squeezes the upper gasket 4 to reach the upper end of the intermediate cavity 9, and the first reciprocating upsetting pass is completed.

[0045] To further optimize the solution, the mold body is flipped 180° in S3.

[0046] Remove the upper ejector pin 1, flip the mold body 180°, place the upper ejector pin 1 in the flipped mold body, and the upper ejector pin 1 moves downward under pressure to extrude the sample 3, causing the sample 3 to be upset and extruded again, until the upper ejector pin 1 extrudes the upper gasket 4 to reach the upper end of the middle cavity 9, and the second reciprocating upsetting pass is completed. If multiple reciprocating upsetting processes are performed, repeat the above steps.

[0047] A further optimized solution is to stop extrusion when the top of the sample 3 is located at the upper end of the middle cavity 9 and flip the mold body.

[0048] In one embodiment of the present invention, referring to Figure 4 After 2-4 times of reciprocating upsetting by this device, the grains of the aluminum alloy can be refined from more than 100μm-200μm to less than 5μm. The grain refinement effect is significant, which effectively improves the plasticity and toughness of the aluminum-lithium alloy at a low cost.

[0049] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, 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 should not be understood as a limitation on the present invention.

[0050] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A reciprocating upsetting device for grain refinement of aluminum-lithium alloy, comprising a die body, the die body being placed on a hydraulic press, characterized in that: The mold body comprises an upper mold (2) and a lower mold (5), and the upper mold (2) is mounted on the top of the lower mold (5) by means of bolts; An upsetting cavity is provided in the mold body, an upper ejector rod (1), a lower ejector rod (6) and a sample (3) are arranged in the upsetting cavity, the sample (3) is located between the upper ejector rod (1) and the lower ejector rod (6), and is repeatedly upset by the upper ejector rod (1) and the lower ejector rod (6).

2. The reciprocating upsetting device for grain refinement of aluminum-lithium alloy according to claim 1, characterized in that: The upsetting cavity comprises an upper cavity (7) and a lower cavity (8); the upper cavity (7) is arranged in the upper mold (2), and the lower cavity (8) is arranged in the lower mold (5); and the opposite ends of the upper cavity (7) and the lower cavity (8) form an intermediate cavity (9).

3. A reciprocating upsetting device for grain refinement of aluminum-lithium alloy according to claim 2, characterized in that: The diameters of the upper cavity (7) and the lower cavity (8) are smaller than the diameter of the middle cavity (9).

4. A reciprocating upsetting device for grain refinement of aluminum-lithium alloy according to claim 3, characterized in that: A gasket (4) is provided between the sample (3), the upper push rod (1) and the lower push rod (6).

5. A reciprocating upsetting method for grain refinement of aluminum-lithium alloy, applicable to the reciprocating upsetting device for grain refinement of aluminum-lithium alloy as claimed in claim 4, characterized in that: The following steps are involved: S1, heating the mold body and the sample (3); S2, placing the lower push rod (6), the heated sample (3) and the upper push rod (1) into the upsetting cavity in sequence, and squeezing them downwards through the upper push rod (1); S3, after the extrusion is completed, the mold body is turned over, and the upper ejector rod (1) is placed on the upper side to extrude the sample (3); S4. Repeat step S3 to achieve grain refinement.

6. A reciprocating upsetting method for grain refinement of aluminum-lithium alloy according to claim 5, characterized in that: In S2, the upper push rod (1) squeezes the sample (3) to cause the sample (3) to undergo upsetting deformation until the intermediate cavity (9) is filled. After the cavity (9) is filled, the lower push rod (6) is removed to allow the upper push rod (1) to continue squeezing, causing the sample (3) to undergo upsetting and squeezing deformation simultaneously.

7. The reciprocating upsetting method for grain refinement of aluminum-lithium alloy according to claim 5, characterized in that: In S3, the mold body is turned over 180°.

8. The reciprocating upsetting method for grain refinement of aluminum-lithium alloy according to claim 5, characterized in that: When the top end of the sample (3) is located at the upper end of the middle cavity (9), the extrusion is stopped and the mold body is turned over.

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