Aluminum alloy rod and method of making the same

Abstract

The application discloses an aluminum alloy rod and a preparation method thereof, and relates to the technical field of aluminum alloy profiles. The preparation method of the aluminum alloy rod comprises the following steps: (1) providing an aluminum casting rod and preheating the aluminum casting rod; (2) loading the preheated aluminum casting rod into an extrusion cylinder which is preheated in advance, and extruding the aluminum casting rod through an extrusion die to obtain a rod blank, and stopping extrusion at the end of the extrusion, and keeping an extrusion residue in the extrusion cylinder; (3) quenching the rod blank; (4) cutting the quenched rod blank to remove a tail shrinkage part of the quenched rod blank; and (5) stretching and straightening the cut rod blank. By implementing the application, the yield of the aluminum alloy rod can be improved, and the production cost of the aluminum alloy rod can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum alloy profiles, in particular to an aluminum alloy bar and a preparation method thereof. BACKGROUND

[0002] Tail contraction refers to the existence of some discontinuous, non-dense, or even non-layer defects in the middle part of the tail end of some extruded products. The main cause is that the oxidation scale, segregation nodules, oil stains and other impurities on the surface of aluminum ingots enter the product interior, forming defects that destroy the continuity and density of the product organization in a certain pattern. If these defects are not eliminated, the profile will be broken along the non-layer cracks during the subsequent stretching and straightening process, reducing the yield of finished products.

[0003] The common method for eliminating tail contraction defects in the prior art is to lengthen the excess thickness or waste length, and then take a sample plate for macroscopic inspection after sawing the waste. According to the inspection results, it is determined whether the finished product is qualified or not. However, this method will lengthen the production cycle, increase the process scrap quantity, and increase the production cost. Therefore, it is of great significance to simply and quickly eliminate tail contraction.

[0004] On the other hand, in order to accurately eliminate tail contraction defects, a large number of extrusion experiments and macroscopic inspection are often required, which consumes manpower and time and reduces production efficiency. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a preparation method of an aluminum alloy bar, which can simply and quickly eliminate tail contraction defects, improve the yield of aluminum alloy bars, and reduce production costs.

[0006] The technical problem to be solved by the present application is to provide a preparation method of an aluminum alloy bar, which can simply and quickly eliminate tail contraction defects, improve the yield of aluminum alloy bars, and reduce production costs.

[0007] In order to solve the above technical problems, the present application provides a preparation method of an aluminum alloy bar, which comprises:

[0008] (1) providing an aluminum bar and preheating it;

[0009] (2) loading the preheated aluminum bar into an extrusion cylinder preheated in advance, and extruding through an extrusion die to obtain a bar blank; stopping extrusion at the end of extrusion, and retaining an extrusion excess in the extrusion cylinder;

[0010] (3) quenching the bar blank;

[0011] (4) cutting the quenched bar blank to remove the tail contraction part of the quenched bar blank;

[0012] (5) stretching and straightening the cut bar blank;

[0013] Wherein, the length of the tail shrinkage part is calculated according to the following formula:

[0014]

[0015] Wherein, l is the length of the tail shrinkage part, L is the length of the aluminum casting rod, d is the diameter of the rod blank, D is the rod diameter of the aluminum casting rod, is the inner diameter of the extrusion cylinder, h is the thickness of the extrusion pressure, and K is a constant with a value range of 0.18-0.2.

[0016] As an improvement of the above technical solution, in step (5), the amount of stretching and straightening is 0.5-1.5%.

[0017] As an improvement of the above technical solution, in step (2), the extrusion ratio is 10-80, and the extrusion speed is 3-15 m / min.

[0018] As an improvement of the above technical solution, in step (1), the aluminum casting rod is preheated to 480-520℃;

[0019] In step (2), the temperature of the preheated extrusion cylinder is 430-470℃.

[0020] As an improvement of the above technical solution, the extrusion die comprises a die body and a die pad connected to the die body, the die body is provided with a flow guide hole, a die hole and a hollow knife in sequence, and the die pad is provided with a flow channel; the aluminum casting rod flows through the flow guide hole, the die hole, the hollow knife and the flow channel in sequence;

[0021] The diameter of the flow guide hole is 15-30 mm larger than the hole diameter of the die hole, and the flow guide depth of the flow guide hole is 15-30 mm;

[0022] The inner side of the die hole is a working belt, and the length of the working belt is 5-10 mm.

[0023] As an improvement of the above technical solution, the flow guide hole is provided with an annular groove near the die hole, the diameter of the annular groove is 3-10 mm larger than the diameter of the flow guide hole, and the length of the annular groove is 7-15 mm.

[0024] As an improvement of the above technical solution, the hollow knife comprises a first-stage hollow knife arranged near the die hole and a second-stage hollow knife arranged near the flow channel, and the diameter of the second-stage hollow knife is larger than that of the first-stage hollow knife.

[0025] The flow guide hole, the die hole, the first-stage hollow knife, the second-stage hollow knife and the flow channel are coaxially arranged.

[0026] As an improvement of the above technical solution, it further comprises:

[0027] (6) The rod blank after stretching and straightening is sawn and aged.

[0028] As the improvement of the above technical solution, when the aluminum cast bar is 6063 aluminum alloy, K is 0.18;

[0029] When the aluminum cast bar is 6005 aluminum alloy, K is 0.185;

[0030] When the aluminum cast bar is 6061 aluminum alloy, K is 0.192;

[0031] When the aluminum cast bar is 6082 aluminum alloy, K is 0.198.

[0032] Correspondingly, the application also discloses an aluminum alloy bar prepared by the preparation method of the aluminum alloy bar.

[0033] The application has the following beneficial effects:

[0034] In the preparation method of the aluminum alloy bar, the tail shrinkage part is directly cut off after the bar blank is extruded and quenched, so that the subsequent influence on the tensile straightening process is prevented, the yield of the aluminum alloy bar is effectively improved, and the production cost is reduced. The length of the tail shrinkage part cut in the application is calculated according to the length of the aluminum cast bar, the rod diameter of the aluminum cast bar, the diameter of the bar blank, the inner diameter of the extrusion cylinder and the thickness of the extrusion pressure surplus. The length of the tail shrinkage part is not only high in accuracy, but also avoids a large amount of length verification and batch inspection work of the tail shrinkage part, simplifies the production process, saves manpower and material resources, and has high production efficiency in the bar extrusion production. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a flow chart of the preparation method of the aluminum alloy bar in an embodiment of the application;

[0036] Figure 2 is a structural schematic diagram of an extrusion die in an embodiment of the application;

[0037] Figure 3 is a physical diagram of an extruded bar sample after alkaline etching in embodiment 1 of the application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the application more clear, the application will be further described in detail below with reference to the specific embodiments.

[0039] The application discloses a preparation method of an aluminum alloy bar, which comprises the following steps:

[0040] S1: providing an aluminum cast bar and preheating the aluminum cast bar;

[0041] Specifically, the temperature of the preheated aluminum cast bar is 480-530℃, and is exemplarily 490℃, 500℃, 510℃ or 525℃, but is not limited thereto. Preferably, the temperature is 480-520℃.

[0042] S2: extruding the preheated aluminum cast bar to obtain a bar blank;

[0043] In the method, the preheated aluminum cast bar is loaded into the preheated extrusion cylinder and extruded through the extrusion die to obtain a bar blank. At the end of the extrusion, the extrusion is stopped, and the extrusion pressure remains in the extrusion cylinder. It should be noted that a certain amount of aluminum alloy remains in the extrusion die and the extrusion cylinder after the extrusion is stopped, and the part remaining in the extrusion cylinder is the extrusion pressure. The extrusion cylinder is retracted, and the extrusion pressure is removed from the extrusion cylinder. The extrusion pressure is actively sheared between the extrusion cylinder and the extrusion die by a shearing device, so as to remove the extrusion pressure. After the extrusion pressure is removed, a new aluminum alloy cast bar is loaded, and the next round of extrusion is performed. That is, the stopping of the extrusion in the present application does not mean that the extrusion is completely stopped, but refers to the stage of stopping the extrusion process in the middle of the extrusion of different aluminum alloy cast bars.

[0044] In the method, the preheated aluminum cast bar is loaded into the preheated extrusion cylinder and extruded through the extrusion die to obtain a bar blank. At the end of the extrusion, the extrusion is stopped, and the extrusion pressure remains in the extrusion cylinder. It should be noted that a certain amount of aluminum alloy remains in the extrusion die and the extrusion cylinder after the extrusion is stopped, and the part remaining in the extrusion cylinder is the extrusion pressure. The extrusion cylinder is retracted, and the extrusion pressure is removed from the extrusion cylinder. The extrusion pressure is actively sheared between the extrusion cylinder and the extrusion die by a shearing device, so as to remove the extrusion pressure. After the extrusion pressure is removed, a new aluminum alloy cast bar is loaded, and the next round of extrusion is performed. That is, the stopping of the extrusion in the present application does not mean that the extrusion is completely stopped, but refers to the stage of stopping the extrusion process in the middle of the extrusion of different aluminum alloy cast bars.

[0045] In the method, the preheated aluminum cast bar is loaded into the preheated extrusion cylinder and extruded through the extrusion die to obtain a bar blank. At the end of the extrusion, the extrusion is stopped, and the extrusion pressure remains in the extrusion cylinder. It should be noted that a certain amount of aluminum alloy remains in the extrusion die and the extrusion cylinder after the extrusion is stopped, and the part remaining in the extrusion cylinder is the extrusion pressure. The extrusion cylinder is retracted, and the extrusion pressure is removed from the extrusion cylinder. The extrusion pressure is actively sheared between the extrusion cylinder and the extrusion die by a shearing device, so as to remove the extrusion pressure. After the extrusion pressure is removed, a new aluminum alloy cast bar is loaded, and the next round of extrusion is performed. That is, the stopping of the extrusion in the present application does not mean that the extrusion is completely stopped, but refers to the stage of stopping the extrusion process in the middle of the extrusion of different aluminum alloy cast bars.

[0046]

[0047] In the method, the preheated aluminum cast bar is loaded into the preheated extrusion cylinder and extruded through the extrusion die to obtain a bar blank. At the end of the extrusion, the extrusion is stopped, and the extrusion pressure remains in the extrusion cylinder. It should be noted that a certain amount of aluminum alloy remains in the extrusion die and the extrusion cylinder after the extrusion is stopped, and the part remaining in the extrusion cylinder is the extrusion pressure. The extrusion cylinder is retracted, and the extrusion pressure is removed from the extrusion cylinder. The extrusion pressure is actively sheared between the extrusion cylinder and the extrusion die by a shearing device, so as to remove the extrusion pressure. After the extrusion pressure is removed, a new aluminum alloy cast bar is loaded, and the next round of extrusion is performed. That is, the stopping of the extrusion in the present application does not mean that the extrusion is completely stopped, but refers to the stage of stopping the extrusion process in the middle of the extrusion of different aluminum alloy cast bars.

[0048] Specifically, the method for preparing the aluminum alloy bar of the present application can be applied to various types of bar dies, such as the flat die commonly used in the art, but is not limited thereto. Preferably, in one embodiment of the present application, see Figure 2 ​The extrusion die comprises a die body 1 and a die pad 2 connected with the die body 1, the die body 1 is internally provided with a flow guide hole 11, a die hole 12 and a hollow cutter 13 which are sequentially communicated, and the die pad 2 is internally provided with a flow channel 21; the aluminum casting rod sequentially flows through the flow guide hole 11, the die hole 12, the hollow cutter 13 and the flow channel 21. The flow guide hole 11 is in a straight cylinder shape, i.e. the die angle is 90°; the flow guide depth of the flow guide hole 11 (i.e. the length α of the flow guide hole 11) is 15-30 mm, and the diameter (β) thereof is 15-30 mm larger than the diameter of the die hole 12. The shallow right-angle type feeding flow guide hole can avoid excessive aluminum storage at the feeding opening, thereby avoiding the occurrence of a long head-tail material transverse welding (a structure defect also referred to as “delamination”) at the head of the extruded product, reducing the length of the head waste, and enabling the process waste to be concentrated at the tail end, thereby making the subsequent cutting process simpler.

[0049] The flow guide hole 11 is provided with an annular groove 14 near the die hole 12, the diameter (γ) of the annular groove 14 is 3-10 mm larger than the diameter (β) of the flow guide hole 11, and the length thereof is 7-15 mm. When the extrusion pressure cut is performed after the extrusion is stopped, the aluminum alloy embedded in the annular groove 14 has a certain adhesion resistance, thereby avoiding the shearing of the aluminum storage in the die flow guide hole 11 when the extrusion pressure cut is performed, ensuring the accuracy of the subsequent extrusion pressure thickness measurement, further improving the accuracy of the length measurement of the tail end, and facilitating the subsequent continuous extrusion.

[0050] The die hole 12 is in a straight cylinder shape, and the inner side surface thereof is a working belt 12a. The length of the working belt 12a is 5-10 mm.

[0051] The hollow cutter 13 comprises a first-stage hollow cutter 13a arranged near the die hole 12 and a second-stage hollow cutter 13b arranged near the flow channel 21, and the flow guide hole 11, the die hole 12, the first-stage hollow cutter 13a, the second-stage hollow cutter 13b and the flow channel 21 are coaxially arranged. The diameter of the second-stage hollow cutter 13b is larger than the diameter of the first-stage hollow cutter 13a. Based on the scheme, the support for the extrusion die can be improved.

[0052] S3: quenching the rod blank;

[0053] Specifically, water cooling, water mist cooling or a combination of the two can be used for quenching, but the present application is not limited thereto. The specific quenching process can be determined according to the specific material, diameter and other shape parameters of the aluminum casting rod.

[0054] S4: cutting the quenched rod blank to form a tail end;

[0055] The length of the tail end is calculated according to the following formula:

[0056]

[0057] Wherein, l is the length of the tail part, L is the length of the aluminum casting rod, d is the diameter of the rod blank, D is the rod diameter of the aluminum casting rod, is the inner diameter of the extrusion cylinder, h is the thickness of the extrusion excess, K is a constant, and the value range of K is 0.18-0.2.

[0058] Specifically, when the aluminum casting rod is 6063 aluminum alloy, K is 0.18; when the aluminum casting rod is 6005 aluminum alloy, K is 0.185; when the aluminum casting rod is 6061 aluminum alloy, K is 0.192; and when the aluminum casting rod is 6082 aluminum alloy, K is 0.198. By controlling the value of K, the influence of the material of the aluminum alloy rod on the length of the tail part can be considered, and the accuracy of the determination is improved.

[0059] Based on the above calculation formula, the length of the tail part can be quickly and accurately determined. The data basis is provided for subsequent cutting processing, and the thickness of the extrusion excess is also reduced. Specifically, for the traditional aluminum alloy rod based on the plane die extrusion, in order to control the tail defect, the thickness of the extrusion excess is controlled to be 60-80 mm, and the present application only needs 20-40 mm.

[0060] S5: stretching and straightening the cut rod blank;

[0061] Wherein, the stretching machine is used for straightening the rod blank, and the stretching and straightening amount is 0.5-1.5%. The tail part is removed before stretching and straightening in the present application, so that the yield of the straightening process is improved. According to statistics, the yield of the stretching and straightening process is 99.3% when the tail part is not removed, and the yield can be improved to 99.9% based on the process of the present application.

[0062] Since the tail part is removed by cutting before stretching and straightening in the present application, the stretching machine can be pulled with a larger traction force, so that the stretching and straightening amount is relatively high. Therefore, the present application can be applied to the preparation of rod blanks with larger length.

[0063] Preferably, in an embodiment of the present application, the preparation method of the aluminum alloy rod further comprises the following steps:

[0064] S6: sawing and aging treatment of the rod blank after stretching and straightening;

[0065] Specifically, sawing refers to sawing the rod blank with large length according to the product length requirement, subsequent process requirement and the like, so as to shorten the length. For example, the length of the rod blank after extrusion is generally 30-40 m, and the length is about 2-3 m after sawing.

[0066] Wherein, the aging treatment can select appropriate temperature and time according to the aluminum alloy material and performance requirement.

[0067] The application will be further described below with specific examples.

[0068] Test Example 1

[0069] This test example tests the accuracy of the tail contraction degree calculation formula in the application.

[0070] Specifically, the material of the aluminum alloy bar is 6061 aluminum alloy, which is obtained by extruding an aluminum cast bar through a forward extrusion process. The mold structure used in the extrusion is shown in Figure 1 Specifically, the extrusion mold includes a mold body 1 and a mold pad 2 connected to the mold body 1. The mold body 1 is provided with a flow guide hole 11, a die hole 12, a first level air knife 13a and a second level air knife 13b which are sequentially communicated, and the mold pad 2 is provided with a flow channel 21. The flow hole 11, the die hole 12, the first level air knife 13a, the second level air knife 13b and the flow channel 21 are coaxially arranged. Among them, the flow guide hole 11 is a straight cylinder, that is, the die angle is 90°; the flow guide depth of the flow guide hole 11 (i.e. the length of the flow guide hole 11) is 30mm, and its diameter is 30mm larger than that of the die hole 12. The flow guide hole 11 is provided with an annular groove 14 near the die hole 12, which has a diameter of 5mm larger than that of the flow guide hole 11 and a length of 15mm. The die hole 12 is a straight cylinder, and its inner side is a working belt 12a. The length of the working belt 12a is 9mm.

[0071] The extrusion process conditions are as follows: the extrusion speed is 8m / min, the temperature of the aluminum cast bar is 500℃, the temperature of the extrusion cylinder is 460℃, and the extrusion ratio is 45.65.

[0072] After extrusion, the diameter of the aluminum alloy bar is 74mm; the barrel diameter of the extrusion cylinder is 500mm, the bar diameter of the aluminum cast bar is 482mm, and the length is 1100mm; the thickness of the extrusion pressure is 30mm.

[0073] Then the length of the tail contraction part is:

[0074]

[0075] The sample bars of 1m, 2m, 3m, 4m, 5m, 6m, 7m and 8m are respectively taken for alkali washing, and the actual figure after alkali washing is shown in Figure 3 The figure shows that from left to right, it is 8m, 7m, 6m, 5m, 4m, 3m, 2m and 1m. As can be seen from the figure, the 7m low-magnification structure shows tail contraction, and the 8m shows no tail contraction, so the length of the tail contraction part is greater than 7m and less than 8m, which is consistent with the calculated value. It can be seen that the calculation formula of the length of the tail contraction part in the application is accurate.

[0076] Example 1

[0077] The application provides a preparation method of an aluminum alloy bar, which comprises the following steps:

[0078] (1) providing an aluminum casting rod and preheating it;

[0079] Specifically, the aluminum casting rod is made of 6063 material, and the temperature after preheating is 495℃;

[0080] (2) loading the preheated aluminum casting rod into the preheated extrusion cylinder, and extruding through the extrusion die to obtain a rod blank, and there is residual extrusion pressure in the extrusion cylinder after extrusion;

[0081] Wherein, the temperature of the preheated extrusion cylinder is 450℃, the extrusion process is forward extrusion process, the extrusion ratio is 45.65, and the extrusion speed is 10m / min;

[0082] The die structure used in extrusion is as shown in Figure 2 Specifically, the extrusion die includes a die body 1 and a die pad 2 connected with the die body 1, and the die body 1 is provided with a flow guide hole 11, a die hole 12, a first empty knife 13a and a second empty knife 13b which are sequentially communicated, and the die pad 2 is provided with a flow channel 21; the flow hole 11, the die hole 12, the first empty knife 13a, the second empty knife 13b and the flow channel 21 are coaxially arranged. Wherein, the flow guide hole 11 is in a straight cylinder shape, i.e. the die angle is 90°; the flow guide depth of the flow guide hole 11 (i.e. the length of the flow guide hole 11) is 30mm, and its diameter is 30mm larger than that of the die hole 12. The flow guide hole 11 is provided with an annular groove 14 near the die hole 12, which has a diameter of 5mm larger than that of the flow guide hole 11 and a length of 15mm. The die hole 12 is in a straight cylinder shape, and its inner side is a working belt 12a. The length of the working belt 12a is 9mm.

[0083] (3) quenching the rod blank;

[0084] Specifically, the rod blank after extrusion is water-cooled and quenched in line.

[0085] (4) cutting the rod blank after quenching to remove the tail shrinkage part of the rod blank after quenching;

[0086] Wherein, the length of the tail shrinkage part is:

[0087]

[0088] Wherein, L is the length of the aluminum casting rod, which is 1100mm, d is the diameter of the rod blank, which is 74mm, D is the rod diameter of the aluminum casting rod, which is 482mm; is the inner diameter of the extrusion cylinder, which is 500mm, h is the thickness of the extrusion pressure, which is 30mm, and K is a constant, which is 0.18.

[0089] Specifically, in order to ensure that the tail shrinkage part is removed completely, a sawing equipment is used to cut at the tail part of 7.5m.

[0090] (5) stretching and straightening the cut rod blank;

[0091] Specifically, the stretching and straightening amount is 0.8%.

[0092] (6) sawing and aging the stretched and straightened rod blank.

[0093] The aging temperature is 180°C, and the aging time is 3h.

[0094] The above describes the preferred embodiments of the application. It should be noted that, for those skilled in the art, without departing from the principles of the application, a number of improvements and refinements can be made, which are also considered within the scope of protection of the application.

Claims

1. A method of producing an aluminum alloy rod, characterized by, The method comprises the following steps: (1) providing an aluminum cast bar and preheating the same; (2) loading the preheated aluminum cast bar into an extrusion cylinder preheated in advance and extruding the same through an extrusion die to obtain a bar blank; stopping extrusion at the end of the extrusion, and leaving an extrusion residue in the extrusion cylinder; (3) quenching the bar blank; (4) cutting the quenched bar blank to remove a tail portion of the quenched bar blank; (5) stretch straightening the cut bar blank; wherein the length of the tail portion is calculated according to the following formula: wherein l is the length of the tail portion, L is the length of the aluminum cast bar, d is the diameter of the bar blank, D is the diameter of the aluminum cast bar, φ is the inner diameter of the extrusion cylinder, h is the thickness of the extrusion residue, and K is a constant, and the value range of K is 0.18-0.

2.

2. The method of producing an aluminum alloy rod according to claim 1, wherein In step (5), the stretch straightening amount is 0.5-1.5%.

3. The method of producing an aluminum alloy rod according to claim 1, wherein In step (2), the extrusion ratio is 10-80, and the extrusion speed is 3-15 m / min.

4. The method of producing an aluminum alloy rod according to claim 1, wherein In step (1), the aluminum cast bar is preheated to 480-520 ℃. In step (2), the temperature of the preheated extrusion cylinder is 430-470 ℃.

5. The method of producing an aluminum alloy rod according to claim 1, wherein The extrusion die comprises a die body and a die pad connected to the die body, the die body is provided with a flow guide hole, a die hole and a hollow tooth in sequence, and the die pad is provided with a flow channel; the aluminum cast bar flows through the flow guide hole, the die hole, the hollow tooth and the flow channel in sequence; The diameter of the flow guide hole is 15-30 mm larger than the hole diameter of the die hole, and the flow guide depth of the flow guide hole is 15-30 mm; The inner side of the die hole is a working belt, and the length of the working belt is 5-10 mm.

6. The method of producing an aluminum alloy rod according to claim 5, wherein The flow guide hole is provided with an annular groove close to the die hole, and the diameter of the annular groove is 3-10 mm larger than the diameter of the flow guide hole, and the length of the annular groove is 7-15 mm.

7. The method of producing an aluminum alloy rod according to claim 5, wherein The hollow tooth comprises a first-stage hollow tooth close to the die hole and a second-stage hollow tooth close to the flow channel, and the diameter of the second-stage hollow tooth is larger than that of the first-stage hollow tooth; The flow guide hole, the die hole, the first-stage hollow tooth, the second-stage hollow tooth and the flow channel are coaxially arranged.

8. The method of producing an aluminum alloy rod according to claim 1, wherein Further comprising: (6) sawing and aging the stretch straightened bar blank.

9. The method of producing an aluminum alloy rod according to claim 1, wherein When the aluminum cast bar is 6063 aluminum alloy, K is 0.18; When the aluminum cast bar is 6005 aluminum alloy, K is 0.185; When the aluminum cast bar is 6061 aluminum alloy, K is 0.192; When the aluminum cast bar is 6082 aluminum alloy, K is 0.198.

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