A method for processing and forming an aluminum alloy boom structure, a structure and a die

Abstract

This invention provides a processing and forming method, structure, and mold for an aluminum alloy boom structure. The processing and forming method includes: extruding a large-section aluminum alloy profile to obtain a hollow thin-walled profile, and machining it to obtain the main boom; extruding an integral copper-aluminum composite bushing to obtain the bushing; and connecting the main boom and the bushing using a high-strength connection process to obtain the aluminum alloy boom structure. The prepared boom structure has advantages such as high connection strength, small deformation, and light weight, making it suitable for ultra-high-distance operations. This aluminum alloy boom includes two structures: an aluminum alloy profile main boom and an integrally formed composite bushing. The aluminum alloy profile main boom is integrally formed by extrusion, and the composite bushing is integrally formed by a composite extrusion method. The two are connected by riveting and friction stir welding for high strength, resulting in advantages such as high connection strength, small deformation, and light weight, making it suitable for ultra-high-distance operations.

Description

Technical Field

[0001] This invention belongs to the field of aerial machinery and engineering machinery technology, specifically relating to a processing and forming method, structure and mold for an aluminum alloy boom structure. Background Technology

[0002] The boom is the main working device of aerial work platforms, construction machinery, and other equipment, used to raise or extend the working radius to achieve large-span operations. It is a key core component of large machinery such as aerial work platforms, aerial work vehicles, truck-mounted cranes, mobile cranes, and concrete pump trucks. Working height is a key competitive advantage of this type of lifting or extending machinery, and the boom's own weight is a crucial factor affecting working height, fuel consumption reduction, and chassis downgrading. Booms are typically formed by welding or bending steel plates together. Currently, weight reduction is usually achieved through structural lightweighting and the use of high-strength steel plates, but these methods are gradually approaching their limits. This is because the high density of steel and the insufficient rigidity resulting from thinner walls are multiple contradictions that have remained unresolved. Aluminum alloy, with a density only about one-third that of steel, is an ideal material for boom weight reduction. Currently, the overall forming scheme for aluminum alloy booms is a welded structure, but aluminum alloys have disadvantages such as high strength, poor welding reliability, large thermal deformation, and low fatigue life of arc weld joints. Furthermore, connections between booms, and between the boom and the base or working device, are typically achieved using pin-and-sleeve hinges. For aluminum alloy booms with welded structures, the common method is welded connection, where wear-resistant sleeves are nested into aluminum alloy weld sleeves, which are then welded to the aluminum alloy boom. This method has several drawbacks: firstly, it requires larger and thicker aluminum alloy weld sleeves, significantly reducing weight reduction; secondly, it suffers from issues such as easy movement of the wear-resistant sleeves, low welding reliability of the aluminum alloy weld sleeves, and significant overall boom deformation after welding.

[0003] Existing technical solution 1: Welded steel boom; heavy weight. Reducing the boom thickness leads to insufficient overall rigidity, and the application of ultra-high strength steel has problems such as insufficient welding fatigue life, making further weight reduction difficult.

[0004] Existing technical solution two: welded aluminum alloy boom. High-strength aluminum alloy has poor welding reliability, low welding fatigue life, and insufficient impact resistance. Furthermore, connecting aluminum alloy booms with other steel structures is difficult, resulting in problems such as low connection strength and poor connection reliability.

[0005] The disadvantage of welded steel booms is their heavy weight. The disadvantages of welded aluminum alloy booms are: low welding reliability leading to premature boom failure and short fatigue life; large welding deformation resulting in low precision of boom hinge connections, high vibration, and easy damage; and the wear-resistant bushings and aluminum alloy welded sleeves are fixed by an interference fit, but the low strength and easy deformation of aluminum alloy lead to problems such as early slippage and movement of the wear-resistant bushings. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a processing and forming method, structure and mold for aluminum alloy boom structures. The prepared boom structure has the advantages of high connection strength, small deformation and light weight, and is suitable for ultra-high distance operations.

[0007] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0008] In a first aspect, the present invention provides a method for processing and forming an aluminum alloy boom structure, comprising:

[0009] Large-section aluminum alloy profiles are extruded to obtain hollow thin-walled profiles, which are then machined to obtain the main arm.

[0010] The bushing is obtained by extrusion forming of an integral copper-aluminum composite bushing;

[0011] The main boom and bushing are connected using a high-strength connection process to obtain an aluminum alloy boom structure.

[0012] Furthermore, the extrusion forming of large-section aluminum alloy profiles includes:

[0013] It adopts high-strength aluminum alloy extruded hollow profiles with a minimum cross-sectional size of 100×100mm and a minimum wall thickness of 3mm;

[0014] Extrusion parameter settings: extrusion temperature 420-440℃, die temperature 470-490℃, ingot temperature 490-510℃, quenching method: water quenching, air quenching, mist quenching or combined quenching.

[0015] Extrusion exit temperature: 510-530℃, quenching temperature: ≤100℃;

[0016] The stretching and straightening process involves a stretching rate of 0.8% to 1.5%, and the surface must be free of orange peel defects. The aging process is carried out at 175℃ for 8-12 hours.

[0017] Furthermore, the extrusion parameters for large-section aluminum alloy profiles are as follows:

[0018] Extrusion temperature: 430℃, die temperature: 485℃, ingot temperature: 500℃, profile extrusion exit temperature: 525℃;

[0019] The quenching method adopts multi-stage quenching, which consists of air quenching, mist quenching, and water quenching.

[0020] Based on the characteristics of hollow thin-walled large cross-section, an annular groove type water tank seal is designed.

[0021] The first stage is air quenching, which is designed with a dual-blowing mode from top and bottom, and the cooling rate is controlled at 10℃ / s.

[0022] The second stage is mist quenching. The mist quenching design has four covering devices in the top, bottom, left and right. The water mist flow rate of each spray covering device is adjustable. The water mist flow rate is designed according to the length ratio of the long and short sides. The water mist flow rate is 10L / min per 10mm.

[0023] The third stage is water quenching, with a water flow rate of 20L / min in the quenching tank and a cooling rate controlled at 25℃ / s.

[0024] Temperature after multi-stage quenching: ≤90℃.

[0025] The stretching and straightening process has a stretching rate of 1.1%, and the surface is free of orange peel defects. The aging process is carried out at 180℃ for 9 hours.

[0026] Furthermore, the extrusion forming of the copper-aluminum integrated composite bushing includes:

[0027] A composite bushing is formed by extruding a high-strength brass and high-strength aluminum alloy composite rod into a composite bushing with a wear-resistant high-strength brass interior, a high-strength aluminum alloy exterior, and a high-strength aluminum alloy connecting support plate at the bottom.

[0028] Furthermore, the extrusion forming of the copper-aluminum integrated composite bushing includes:

[0029] Design extrusion dies and complete their processing, manufacturing, and assembly;

[0030] The aluminum alloy billet and copper alloy billet are processed in advance, and the composite billet formed after assembly is heated and kept warm.

[0031] All working surfaces inside the mold are coated with high-temperature lubricant. The mold is preheated: the core mold is heated to 200°C, the extrusion punch to 200°C, and the cone mold to 395°C. The temperatures are all measured in real time and accurately by thermocouples built into the mold.

[0032] Take out the composite blank heated to the specified temperature, quickly spray high-temperature lubricant on the outer surface, and then quickly put it into the extrusion die.

[0033] Install the upper and lower dies on the worktable and upper slide of the pressure equipment, respectively. Start the pressure equipment, and the upper die begins to work at an extrusion speed of 5 mm / min. The composite billet enters the cavity through the composite working blade formed by the first working blade of the conical die, the second working blade of the conical die, and the working blade of the guide plate.

[0034] When the main cylinder has traveled halfway, pause the operation of the main cylinder of the pressure equipment. Deactivate the side cylinder lock function of the pressure equipment and activate the 1MPa back pressure mode. Restart the operation of the main cylinder of the pressure equipment. At this time, the aluminum alloy billet begins to enter the cavity area of ​​the guide plate under the back pressure of the guide plate, forming an integrated composite bushing support plate.

[0035] After the main cylinder completes the extrusion stroke, the formed blank is removed and machined for use in the aluminum alloy boom connection structure.

[0036] Furthermore, large-section aluminum alloy profiles and integrated copper-aluminum composite bushings are connected using a high-strength connection process to obtain an aluminum alloy boom structure, including:

[0037] After connecting the large-section aluminum alloy profile and the copper-aluminum integrated composite bushing with ring groove rivets, they are then connected by friction stir welding, forming a double composite connection.

[0038] Furthermore, large-section aluminum alloy profiles and integrated copper-aluminum composite bushings are connected using a high-strength connection process to obtain an aluminum alloy boom structure, including:

[0039] The hollow thin-walled profile is riveted and formed by grooved rivets. Based on the structure and strength characteristics of the hollow thin-walled profile, rivet holes are opened on both sides of the profile and on the composite bushing support plate. B-R10-8 rivets are selected in an array of 4×12.

[0040] Friction stir welding is performed around the outer circumference of the composite bushing support plate, with three friction stir welds arranged along the profile extrusion direction at interval array rivets.

[0041] Furthermore, the design, manufacturing, and assembly of the extrusion die are carried out, including:

[0042] Punch installation: The punch mounting plate, upper template, core die, and extrusion punch are connected by bolts. The punch mounting plate is installed on the slide block of the pressure equipment. The core die has a built-in heating resistance wire, which enables directional heating of the aluminum alloy billet; the extrusion punch also has a built-in heating resistance wire, which provides directional heat preservation or heating of the aluminum alloy and copper alloy billets through its lower working surface.

[0043] Die installation: The conical die and prestressed sleeve are installed on the prestressed pressure plate by bolts. The prestressed pressure plate and the lower template are connected by bolts without interfering with the operation of the side pressure cylinder.

[0044] The lower template is installed on the pressure equipment workbench using bolts. The first guide plate is connected to the first side plate using bolts, and the second guide plate is connected to the second side plate using bolts.

[0045] Insert the flow guide plate 1 and flow guide plate 2 from both sides of the bottom of the die cavity to complete the splicing without fixing. Side pressure cylinder 1 and side pressure cylinder 2 press side pressure plate 1 and side pressure plate 2 respectively and lock them in place.

[0046] Furthermore, the design, manufacturing, and assembly of extrusion dies also include:

[0047] By incorporating a heating resistance wire into the conical die, directional heating of the copper alloy billet can be achieved, including heating before and after forming.

[0048] By incorporating a heating resistance wire into the prestressed sleeve, directional heat preservation or heating of the aluminum alloy layer on the outer side of the formed part can be achieved.

[0049] In a second aspect, the present invention provides an aluminum alloy boom structure, which is manufactured by the method described in the first aspect.

[0050] Thirdly, the present invention provides a mold for processing and forming an aluminum alloy boom structure as described in the first aspect, comprising a punch mounting plate, an upper template, a core mold, an extrusion punch, a prestressed pressure plate, a conical mold, a prestressed sleeve, a first side pressure cylinder, a first side pressure plate, a first guide pressure plate, a working blade of the guide pressure plate, a lower template, a second guide pressure plate, a second side pressure plate, and a second side pressure cylinder.

[0051] The punch mounting plate, upper template, core die, and extrusion punch are connected by bolts, and the punch mounting plate is mounted on the slider of the pressure equipment.

[0052] The core mold has a built-in heating resistance wire for directional heating of the aluminum alloy billet;

[0053] The extrusion punch has a built-in heating resistance wire, which is used to achieve directional heat preservation or heating of aluminum alloy billets and copper alloy billets through the lower working surface.

[0054] The conical mold and the prestressed sleeve are respectively installed on the prestressed pressure plate by bolts, and the prestressed pressure plate is connected to the lower template by bolts.

[0055] The lower template is mounted on the pressure equipment workbench by bolts.

[0056] The first flow guide plate is connected to the first side pressure plate by bolts, and the second flow guide plate is connected to the second side pressure plate by bolts.

[0057] The flow guide plate one and flow guide plate two are installed on the bottom side of the cone mold without being fixed.

[0058] The first and second side pressure cylinders respectively press the first and second side pressure plates and lock them in place.

[0059] Furthermore, the cone mold has a built-in heating resistance wire for directional heating of the copper alloy billet, including heating before and after forming;

[0060] The prestressed sleeve has a built-in heating resistance wire, which is used to achieve directional heat preservation or heating of the aluminum alloy layer on the outside of the formed part.

[0061] Furthermore, the conical die includes a first working edge and a second working edge;

[0062] The first working blade of the cone mold, the second working blade of the cone mold, and the working blade of the flow guide plate form a composite working blade. The relationship between the dimensions of the first working blade of the cone mold (C1), the second working blade of the cone mold (C2), and the working blade of the flow guide plate (C3) is: 2×C1=C2=2×C3.

[0063] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0064] This invention utilizes extruded aluminum alloy profiles as the main boom, offering advantages such as high overall strength, high rigidity, and light weight. The composite bushing, composed of an aluminum alloy body and a wear-resistant layer, is manufactured through integral extrusion forming, resulting in advantages such as light weight, wear resistance, and ease of connection to the aluminum alloy main boom. The aluminum alloy profile main boom and the composite bushing are connected using a high-strength cold-forming method combining riveting and friction stir welding, offering advantages such as high connection strength and minimal deformation. This high-strength, low-deformation connection structure between the aluminum alloy profile main boom and the composite bushing can meet the requirements for multi-stage aluminum alloy booms connected via bushing hinges.

[0065] By combining a one-piece molding structure with a high-strength, low-deformation connection method, the performance advantages of one-piece molding and the high-strength connection effect of composite connections are fully utilized. A cleverly designed composite bushing enables a high-strength transition between the steel and aluminum structures. The main creative effort lies in matching the two one-piece molding processes and methods, as well as the connection processes, to achieve significant weight reduction of the boom while ensuring strength, fatigue life, and connectability. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the aluminum alloy boom structure of the present invention. In the figure, 1-1 is an integrally formed aluminum alloy profile main boom, 1-2 is an integral composite bushing with support plate, 1-3 is a transitional connecting aluminum alloy high-strength plate, 1-4 is an integral composite bushing with support plate, 1-5 is a ring groove rivet, and 1-6 is friction stir welding.

[0067] Figure 2 This is a schematic diagram of the integrated composite bushing structure with support plate of the present invention. In the figure, 2-1 is the wear-resistant inner brass layer; 2-2 is the high-strength aluminum alloy outer layer; and 2-3 is the integrated aluminum alloy support plate.

[0068] Figure 3 This is a schematic diagram of the integrated composite bushing extrusion die structure of the present invention;

[0069] In the diagram, 1. Punch mounting plate; 2. Upper template; 3. Core mold; 4. Extrusion punch; 5. Prestressed pressure plate; 6. Aluminum alloy billet; 7. Copper alloy billet; 8. Conical die; 81. First working edge of conical die; 82. Second working edge of conical die; 9. Cavity; 10. Prestressed sleeve; 11. Side pressure cylinder one; 12. Side pressure plate one; 13. Flow guide pressure plate one; 131. Flow guide pressure plate working edge; 14. Lower template; 15. Flow guide pressure plate two; 16. Side pressure plate two; 17. Side pressure cylinder two. Detailed Implementation

[0070] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0071] In the description of this embodiment, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this embodiment.

[0072] Example 1:

[0073] This embodiment provides a method for processing and forming an aluminum alloy boom structure. Figure 1 The schematic diagram of the aluminum alloy boom structure of the present invention includes an integrally formed aluminum alloy profile main boom 1-1, an integral composite bushing with support plate 1-2, a transitional connecting aluminum alloy high-strength plate 1-3, an integral composite bushing with support plate 2 1-4, a ring groove rivet 1-5, and a friction stir weld 1-6.

[0074] Figure 2 This is a schematic diagram of the integrated composite bushing structure with support plate of the present invention. The bushing includes a wear-resistant inner brass layer 2-1, a high-strength aluminum alloy outer layer 2-2, and an integrally formed aluminum alloy support plate 2-3.

[0075] The specific method is as follows:

[0076] Large-section aluminum alloy profile extrusion forming: High-strength aluminum alloy extruded hollow profiles are used, with a minimum cross-sectional size of 100×100mm and a minimum wall thickness of 3mm. Extrusion parameters are set as follows: extrusion temperature 420-440℃, die temperature 470-490℃, ingot temperature 490-510℃. Quenching methods include water quenching, air quenching, mist quenching, or a combination of quenching. Extrusion exit temperature: 510-530℃, post-quenching temperature: ≤100℃. Tensile straightening has a tensile rate of 0.8%~1.5%, and the surface must be free of orange peel defects. Aging process is performed at 175℃ for 8-12 hours. Process temperature is crucial for ensuring the mechanical properties of the profile.

[0077] Copper-aluminum integrated composite bushing extrusion forming: High-strength brass and high-strength aluminum alloy composite rods are extruded into a composite bushing with wear-resistant high-strength brass inside, high-strength aluminum alloy outside, and a high-strength aluminum alloy connecting support plate at the bottom.

[0078] High-strength connection process: After ring groove riveting, friction stir welding is performed to form a double composite connection.

[0079] Implementation Case:

[0080] Specifically, the extrusion forming of large-section aluminum alloy profiles includes:

[0081] Prepare 6061 aluminum alloy ingots according to national standards, and design extrusion dies according to product drawings (210×310mm, inner wall thickness 5.5mm).

[0082] The extrusion parameters are as follows: extrusion temperature 430℃, die temperature 485℃, ingot temperature 500℃, and profile extrusion exit temperature 525℃. The quenching method employs multi-stage quenching, combining air quenching, mist quenching, and water quenching. Based on the characteristics of the hollow, thin-walled, large-section profile, an annular groove-type water tank seal is designed. The first stage is air quenching, designed with a double-blowing mode from top to bottom, with a cooling rate controlled at 10℃ / s. The second stage is mist quenching, designed with four covering devices (top, bottom, left, and right). The water mist flow rate of each spray covering device is adjustable, with the long and short sides designed according to the length ratio. The water mist flow rate is 10L / min per 10mm to ensure reduced deformation and lateral bending, and improved performance. The third stage is water quenching, with a water flow rate of 20L / min in the quenching tank and a cooling rate controlled at 25℃ / s. The temperature after multi-stage quenching is ≤90℃. The tensile straightening elongation rate is 1.1%, with no orange peel defects on the surface. The aging process is performed at 180℃ for 9 hours.

[0083] Hollow thin-walled profiles are obtained, and the main arm is obtained through machining.

[0084] Specifically, the extrusion forming of copper-aluminum integrated composite bushings includes:

[0085] Using 6061-T6 aluminum alloy tubing and high-strength brass rods, a composite billet with an inner brass rod and an outer aluminum alloy tubing is prepared and heated and kept warm (250℃×1h).

[0086] The extrusion die is designed, manufactured, and assembled. High-temperature lubricant is applied to all working surfaces inside the die. The die is preheated: core die 3 is heated to 200°C, extrusion punch 4 to 200°C, and cone die 8 to 395°C. Temperatures are measured accurately in real-time using thermocouples built into the die. The composite blank, heated to the specified temperature, is removed, its outer surface is quickly sprayed with high-temperature lubricant, and then it is rapidly placed into the extrusion die.

[0087] The mold structure is shown in the mold example below. The mold (divided into upper and lower molds) is installed on the worktable and upper slide of the pressure equipment, respectively. The pressure equipment adopts a conventional multi-directional forming hydraulic press. The main cylinder moves vertically, and the side cylinders move horizontally (one on each side). Both the main cylinder and the side cylinders are operated through the hydraulic press controller.

[0088] The pressure equipment is started, and the upper die begins operation at an extrusion speed of 5 mm / min. The composite billet enters the cavity through the composite working blade formed by the first working blade 81, the second working blade 82 of the conical die, and the working blade 131 of the guide plate. When the main cylinder stroke is halfway through, the main cylinder operation is paused. The side pressure cylinder locking function is turned off, and the 1 MPa back pressure mode is activated. This is because: initially, both side pressure cylinders are locked, and the cavity is fixed. According to calculations, when the main cylinder stroke is halfway through, the side pressure cylinder locking function needs to be turned off. At this time, the side pressure cylinder can move, but it needs to be subjected to a back pressure of 1 MPa to retract. Under the action of back pressure, a guide plate cavity is formed at the bottom, ultimately forming a high-performance integrated composite bushing support plate.

[0089] Restart the main cylinder. At this time, the aluminum alloy billet begins to enter the cavity area of ​​the guide plate under the back pressure of the guide plate, forming an integrated composite bushing support plate.

[0090] After the main cylinder completes the extrusion stroke, the formed blank is removed and can be used for aluminum alloy boom connection structure after appropriate machining.

[0091] Specifically, high-strength connection technology includes:

[0092] Low-deformation, high-strength cold-joint:

[0093] Connection Process 1: Ring Groove Riveting Connection. Based on the structural and strength characteristics of the hollow thin-walled profile, rivet holes are made on both sides of the profile and the composite bushing support plate. B-R10-8 rivets are selected in an array of 4×12.

[0094] Connection process two: friction stir welding. Friction stir welding is performed around the outer circumference of the composite bushing support plate. Friction stir welds are arranged along the extrusion direction of the profile at interval array rivets, for a total of 3 passes.

[0095] In addition, the integrated composite bushing with support plate can be connected to the integrated extruded high-strength aluminum alloy main arm through a transition connection of high-strength aluminum alloy plate. The connection method is the same low-deformation, high-strength cold connection method.

[0096] Specifically, a concrete embodiment of an integrated composite extrusion die with a support plate and bushing is as follows:

[0097] Punch installation: Punch mounting plate 1, upper template 2, core die 3, and extrusion punch 4 are connected by bolts. Punch mounting plate 1 is installed on the slider of the pressure equipment. Among them, core die 3 has a built-in heating resistance wire, which can realize the directional heating of aluminum alloy billet 6; extrusion punch 4 has a built-in heating resistance wire, which realizes the directional heat preservation or heating of aluminum alloy billet 6 and copper alloy billet 7 through the lower working surface.

[0098] Die installation: Conical die 8 and prestressed sleeve 10 are respectively installed on prestressed pressure plate 5 by bolts. Prestressed pressure plate 5 and lower template 14 are connected by bolts and do not interfere with the operation of side pressure cylinder.

[0099] The lower template 14 is mounted on the pressure equipment workbench by bolts. The first guide plate 13 is connected to the first side plate 12 by bolts, and the second guide plate 15 is connected to the second side plate 16 by bolts.

[0100] The flow guide plate 13 and the flow guide plate 2 15 are inserted from both sides of the bottom of the die cavity to complete the splicing without fixing. The side pressure cylinder 1 and the side pressure cylinder 2 respectively press the side pressure plate 1 and the side pressure plate 2 and lock them in place.

[0101] The conical die 8 has a built-in heating resistance wire, which can realize directional heating of the copper alloy billet 7, including heating before and after forming.

[0102] The prestressed sleeve 10 has a built-in heating resistance wire, which can achieve directional heat preservation or heating of the aluminum alloy layer on the outside of the formed part.

[0103] The first working blade 81, the second working blade 82, and the guide plate working blade 131 form a composite working blade. The dimensions of the first working blade 81 (C1), the second working blade 82 (C2), and the guide plate working blade 131 (C3) are related as follows: 2 × C1 = C2 = 2 × C3. The achievable effects are: the copper alloy billet 7 undergoes two shearing processes (C1 and C2) to form the inner surface layer of the composite bushing, which improves strength and wear resistance; the aluminum alloy billet 6 undergoes one shearing process (C3) to form the outer surface layer of the composite bushing, improving strength; simultaneously, the inner and outer walls of the copper-aluminum composite layer are sheared by the composite working blades formed by C2 and C3, greatly improving the bonding strength between the two, ensuring a high-strength connection of the copper-aluminum composite layer, and achieving an integrated forming effect.

[0104] The specific method for using molds is as follows:

[0105] The aluminum alloy billet 6 and the copper alloy billet 7 were processed in advance and assembled to form a composite billet, which was then heated and kept warm (250℃×1h).

[0106] All working surfaces inside the mold are coated with high-temperature lubricant. The mold is preheated: the core mold 3 is heated to 200°C, the extrusion punch 4 is heated to 200°C, and the cone mold 8 is heated to 395°C. The temperature is measured in real time by thermocouples built into the mold.

[0107] The specific temperatures are for illustrative purposes only. The heating temperatures are determined based on the optimal heat treatment parameters for aluminum alloy and copper alloy billets. At or around these temperatures, the billet achieves the most suitable deformation amount achievable under the deformation requirements of this mold, i.e., the optimal match between deformation and temperature, avoiding the generation of cracks, defects, etc.

[0108] The composite billet, heated to the specified temperature, is removed and quickly coated with a high-temperature lubricant on its outer surface before being rapidly placed into the extrusion die. The pressure equipment is started, and the upper die begins operation at an extrusion speed of 5 mm / min. The composite billet enters the cavity through the composite working edge formed by the first working edge 81, the second working edge 82 of the conical die, and the working edge 131 of the guide plate. When the main cylinder has passed half its stroke, the main cylinder operation is paused. The side pressure cylinder lock function is deactivated, and the 1 MPa back pressure mode is activated. The main cylinder operation is restarted. At this time, the aluminum alloy billet begins to enter the guide plate cavity area under the back pressure of the guide plate, forming an integrated composite bushing support plate.

[0109] After the main cylinder completes the extrusion stroke, the formed blank is removed and can be used for aluminum alloy boom connection structure after appropriate machining.

[0110] The aluminum alloy boom structure of this invention consists of two parts: a main boom made of integrally extruded high-strength aluminum alloy profile and an integral composite bushing with support plate. Alternatively, it can be connected by a transition plate. The connection method is a low-deformation, high-strength cold connection, formed by riveting with ring groove rivets followed by friction stir welding. Specifically, it has the following advantages:

[0111] Advantage 1: The main boom is made of high-strength aluminum alloy in one piece through extrusion, resulting in high overall strength, no weld seams, long fatigue life, and high production efficiency due to the one-piece extrusion molding process, making it suitable for large-scale mass production.

[0112] Advantage 2: The bushing has a composite structure, consisting of a wear-resistant inner layer, a high-strength outer layer, and a transition connection support plate. It is manufactured through an integral molding process, which has the characteristics of high overall bonding strength and wear-resistant inner layer. Furthermore, the overall covering structure is made of high-strength aluminum alloy, which is suitable for high-strength connection with aluminum alloy main arm and suitable for high-strength connection through friction stir welding.

[0113] Advantage 3: The connection method is a low-deformation, high-strength cold connection, formed by riveting with ring groove rivets followed by friction stir welding. This connection method has advantages such as minimal deformation, extremely high connection strength, and long fatigue life. Compared with aluminum alloy arc welding, it can significantly reduce welding defects, extend fatigue life, and resist cyclic impact vibration and other working conditions.

[0114] Advantage 4: The overall aluminum alloy structure and integrated bushing design can effectively ensure the strength of the overall aluminum alloy boom and reduce the weight of the entire boom. At the same time, the integrated wear-resistant high-strength bushing design and high-strength connection method can ensure that this high-strength aluminum alloy boom can be connected to other steel booms, steel turntables, steel bases and other steel structures by pin-shaft bushing hinge, which has high connection strength and wide applicability.

[0115] Compared to existing steel supports, the one-piece molded aluminum alloy boom is lighter, reducing weight by 40% compared to the same model of steel support. Compared to the same model of boom using traditional aluminum alloy sheet welding, it reduces weight by 25%. Furthermore, compared to conventional aluminum alloy welded structure booms, it improves overall load-bearing capacity by 32%, bushing wear resistance by 35%, and overall rigidity by 33%.

[0116] In the specific experiments, the researchers found that:

[0117] The aluminum alloy boom prepared by this invention can achieve the following:

[0118] The weight is reduced by 40%, with the steel boom weighing 170kg, the one-piece aluminum alloy boom weighing 102kg, and the aluminum alloy plate welded boom weighing 136kg.

[0119] Load-bearing capacity: The tensile strength of the aluminum alloy welded structure boom is about 210MPa (overall load-bearing capacity 1360kgf), and the tensile strength of the one-piece formed aluminum alloy boom is 310MPa (overall load-bearing capacity 2000kgf).

[0120] Wear resistance is usually proportional to hardness: aluminum alloys have a hardness of 100 HBW, while copper alloys generally have a hardness of 150 to 200 HBW.

[0121] Stiffness comparison (stiffness here refers to deformation ratio): Under the most dangerous working condition with twice the design load, the deformation of the one-piece aluminum alloy boom is 90mm, with a deformation ratio of 1.6%, while the deformation of the aluminum alloy welded structure boom is 2.4% (deformation 135mm).

[0122] The one-piece molded aluminum alloy boom provided by this invention can be made from various series of extrudable aluminum alloy materials. Similarly, the composite bushing aluminum alloy material can also be any extrudable aluminum alloy material. The inner wear-resistant material can be other wear-resistant copper materials or other lightweight alloy materials to achieve similar functions.

[0123] Example 2:

[0124] This embodiment provides an aluminum alloy boom structure, which is prepared by the method described in Embodiment 1. Figure 1 The schematic diagram of the aluminum alloy boom structure of the present invention includes an integrally formed aluminum alloy profile main boom 1-1, an integral composite bushing with support plate 1-2, a transitional connecting aluminum alloy high-strength plate 1-3, an integral composite bushing with support plate 2 1-4, a ring groove rivet 1-5, and a friction stir weld 1-6.

[0125] Figure 2 This is a schematic diagram of the integrated composite bushing structure with support plate of the present invention. The bushing includes a wear-resistant inner brass layer 2-1, a high-strength aluminum alloy outer layer 2-2, and an integrally formed aluminum alloy support plate 2-3.

[0126] Example 3:

[0127] This embodiment provides a mold for processing and forming an aluminum alloy boom structure as described in Embodiment 1, including a punch mounting plate 1, an upper template 2, a core mold 3, an extrusion punch 4, a prestressed pressure plate 5, a conical mold 8, a prestressed sleeve 10, a side pressure cylinder 11, a side pressure plate 12, a flow guide plate 13, a flow guide plate working blade 131, a lower template 14, a flow guide plate 2 15, a side pressure plate 2 16, and a side pressure cylinder 2 17.

[0128] The punch mounting plate 1, the upper template 2, the core mold 3, and the extrusion punch 4 are connected by bolts, and the punch mounting plate 1 is installed on the slider of the pressure equipment.

[0129] The core mold 3 has a built-in heating resistance wire for directional heating of the aluminum alloy billet 6.

[0130] The extrusion punch 4 has a built-in heating resistance wire, which is used to achieve directional heat preservation or heating of the aluminum alloy billet 6 and the copper alloy billet 7 through the lower working surface.

[0131] The conical mold 8 and the prestressed sleeve 10 are respectively installed on the prestressed pressure plate 5 by bolts, and the prestressed pressure plate is connected to the lower template 14 by bolts.

[0132] The lower template 14 is mounted on the pressure equipment workbench by bolts.

[0133] The flow guiding plate 13 and the side pressure plate 12 are connected by bolts, and the flow guiding plate 15 and the side pressure plate 16 are connected by bolts.

[0134] The flow guide plate 13 and the flow guide plate 2 15 are installed on the bottom side of the cone mold 8 without being fixed.

[0135] The side pressure cylinder 11 and the side pressure cylinder 17 respectively press the side pressure plate 12 and the side pressure plate 16 and lock them in place.

[0136] The cone mold 8 has a built-in heating resistance wire for directional heating of the copper alloy billet 7, including heating before and after forming.

[0137] The prestressed sleeve 10 has a built-in heating resistance wire, which is used to achieve directional heat preservation or heating of the aluminum alloy layer on the outside of the formed part.

[0138] The cone die 8 includes a first working edge 81 and a second working edge 82.

[0139] The first working blade 81, the second working blade 82, and the flow guide plate working blade 131 form a composite working blade. The dimensions of the first working blade 81 (C1), the second working blade 82 (C2), and the flow guide plate working blade 131 (C3) are related as follows: 2×C1=C2=2×C3.

[0140] Installation methods include:

[0141] Punch installation: Punch mounting plate 1, upper template 2, core die 3, and extrusion punch 4 are connected by bolts. Punch mounting plate 1 is installed on the slider of the pressure equipment. Among them, core die 3 has a built-in heating resistance wire, which can realize the directional heating of aluminum alloy billet 6; extrusion punch 4 has a built-in heating resistance wire, which realizes the directional heat preservation or heating of aluminum alloy billet 6 and copper alloy billet 7 through the lower working surface.

[0142] Die installation: Conical die 8 and prestressed sleeve 10 are respectively installed on prestressed pressure plate 5 by bolts. Prestressed pressure plate 5 and lower template 14 are connected by bolts and do not interfere with the operation of side pressure cylinder.

[0143] The lower template 14 is mounted on the pressure equipment workbench by bolts. The first guide plate 13 is connected to the first side plate 12 by bolts, and the second guide plate 15 is connected to the second side plate 16 by bolts.

[0144] The flow guide plate 13 and the flow guide plate 2 15 are inserted from both sides of the bottom of the die cavity to complete the splicing without fixing. The side pressure cylinder 1 and the side pressure cylinder 2 respectively press the side pressure plate 1 and the side pressure plate 2 and lock them in place.

[0145] The conical die 8 has a built-in heating resistance wire, which can realize directional heating of the copper alloy billet 7, including heating before and after forming.

[0146] The prestressed sleeve 10 has a built-in heating resistance wire, which can achieve directional heat preservation or heating of the aluminum alloy layer on the outside of the formed part.

[0147] The first working blade 81, the second working blade 82, and the guide plate working blade 131 form a composite working blade. The dimensions of the first working blade 81 (C1), the second working blade 82 (C2), and the guide plate working blade 131 (C3) are related as follows: 2 × C1 = C2 = 2 × C3. The achievable effects are: the copper alloy billet 7 undergoes two shearing processes (C1 and C2) to form the inner surface layer of the composite bushing, which improves strength and wear resistance; the aluminum alloy billet 6 undergoes one shearing process (C3) to form the outer surface layer of the composite bushing, improving strength; simultaneously, the inner and outer walls of the copper-aluminum composite layer are sheared by the composite working blades formed by C2 and C3, greatly improving the bonding strength between the two, ensuring a high-strength connection of the copper-aluminum composite layer, and achieving an integrated forming effect.

[0148] The specific method for using molds is as follows:

[0149] The aluminum alloy billet 6 and the copper alloy billet 7 were processed in advance and assembled to form a composite billet, which was then heated and kept warm (250℃×1h).

[0150] All working surfaces inside the mold are coated with high-temperature lubricant. The mold is preheated: the core mold 3 is heated to 200°C, the extrusion punch 4 is heated to 200°C, and the cone mold 8 is heated to 395°C. The temperature is measured in real time by thermocouples built into the mold.

[0151] The specific temperatures are for illustrative purposes only. The heating temperatures are determined based on the optimal heat treatment parameters for aluminum alloy and copper alloy billets. At or around these temperatures, the billet achieves the most suitable deformation amount achievable under the deformation requirements of this mold, i.e., the optimal match between deformation and temperature, avoiding the generation of cracks, defects, etc.

[0152] The composite billet, heated to the specified temperature, is removed and quickly coated with a high-temperature lubricant on its outer surface before being rapidly placed into the extrusion die. The pressure equipment is started, and the upper die begins operation at an extrusion speed of 5 mm / min. The composite billet enters the cavity through the composite working edge formed by the first working edge 81, the second working edge 82 of the conical die, and the working edge 131 of the guide plate. When the main cylinder has passed half its stroke, the main cylinder operation is paused. The side pressure cylinder lock function is deactivated, and the 1 MPa back pressure mode is activated. The main cylinder operation is restarted. At this time, the aluminum alloy billet begins to enter the guide plate cavity area under the back pressure of the guide plate, forming an integrated composite bushing support plate.

[0153] After the main cylinder completes the extrusion stroke, the formed blank is removed and can be used for aluminum alloy boom connection structure after appropriate machining.

[0154] The main innovation of this invention is the combination of a one-piece molded structure with a high-strength, low-deformation connection method. This fully leverages the performance advantages of one-piece molding and the high-strength connection effect of the composite connection. A cleverly designed composite bushing enables a high-strength transition between the steel and aluminum structures. The primary creative effort lies in matching the two one-piece molding processes and methods, as well as the connection process, to achieve significant weight reduction in the boom while ensuring strength, fatigue life, and connectability.

[0155] The above method is merely one general scheme of the present invention. Based on this, the wear-resistant layer and the substrate material can be adjusted accordingly according to actual needs. Although the present invention and its advantages have been described in detail in the above embodiments, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present invention is not limited to the specific embodiments of the processes, apparatus, means, methods, and steps described in the specification. Those skilled in the art will readily understand from the disclosure of the present invention that existing and future processes, apparatus, means, methods, or steps that perform substantially the same function or obtain substantially the same result as the corresponding embodiments described herein can be used according to the present invention. Therefore, the appended claims are intended to include such processes, apparatus, means, methods, or steps within their scope.

[0156] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0157] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0158] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0159] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0160] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for processing and forming an aluminum alloy boom structure, characterized in that, include: Large-section aluminum alloy profiles are extruded to obtain hollow thin-walled profiles, which are then machined to obtain the main arm. The bushing is obtained by extrusion forming of an integral copper-aluminum composite bushing; The main boom and bushing are connected using a high-strength connection process to obtain an aluminum alloy boom structure; Copper-aluminum integrated composite bushing extrusion forming, including: A composite rod of high-strength brass and high-strength aluminum alloy is extruded into a composite bushing with a wear-resistant high-strength brass interior, a high-strength aluminum alloy exterior, and a high-strength aluminum alloy connecting support plate at the bottom. Copper-aluminum integrated composite bushing extrusion forming, including: Design extrusion dies and complete their processing, manufacturing, and assembly; The aluminum alloy billet and copper alloy billet are processed in advance, and the composite billet formed after assembly is heated and kept warm. High-temperature lubricant is applied to all working surfaces inside the mold; the mold is preheated, with the core mold heated to 200°C, the extrusion punch heated to 200°C, and the cone die heated to 395°C. The temperature is measured in real time by thermocouples built into the mold. Take out the composite blank heated to the specified temperature, quickly spray high-temperature lubricant on the outer surface, and then quickly put it into the extrusion die; Install the upper and lower dies of the mold on the worktable and upper slide of the pressure equipment, respectively; start the pressure equipment, the upper die starts to work, and the extrusion speed is 5mm / min; the composite blank enters the cavity through the composite working blade formed by the first working blade of the conical die, the second working blade of the conical die, and the working blade of the guide plate. When the main cylinder has passed halfway, pause the operation of the main cylinder of the pressure equipment; turn off the side cylinder locking function of the pressure equipment and turn on the 1MPa back pressure mode; restart the operation of the main cylinder of the pressure equipment. At this time, the aluminum alloy billet begins to enter the cavity area of ​​the guide plate under the back pressure of the guide plate, forming an integrated composite bushing support plate. After the main cylinder completes the extrusion stroke, the formed blank is removed and machined for use in the aluminum alloy boom connection structure.

2. The processing and forming method of the aluminum alloy boom structure according to claim 1, characterized in that, Large-section aluminum alloy profile extrusion forming, including: It adopts high-strength aluminum alloy extruded hollow profiles with a minimum cross-sectional size of 100×100mm and a minimum wall thickness of 3mm; Extrusion parameter settings: extrusion temperature 420-440℃, die temperature 470-490℃, ingot temperature 490-510℃, quenching method: water quenching, air quenching, mist quenching or combined quenching. Extrusion exit temperature: 510-530℃, quenching temperature: ≤100℃; The stretching and straightening process involves a stretching rate of 0.8% to 1.5%, and the surface must be free of orange peel defects. The aging process is carried out at 175℃ for 8-12 hours.

3. The processing and forming method for the aluminum alloy boom structure according to claim 2, characterized in that, The extrusion parameters for large-section aluminum alloy profiles are as follows: Extrusion temperature: 430℃, die temperature: 485℃, ingot temperature: 500℃, profile extrusion exit temperature: 525℃; The quenching method adopts multi-stage quenching, which consists of air quenching + mist quenching + water quenching; Based on the characteristics of hollow thin-walled large cross-section, an annular groove type water tank seal is designed; The first stage is air quenching, which is designed with a dual-blowing mode from top and bottom, and the cooling rate is controlled at 10℃ / s. The second stage is mist quenching. The mist quenching design has four covering devices in the top, bottom, left and right. The water mist flow rate of each spray covering device is adjustable. The water mist flow rate is designed according to the length ratio of the long and short sides. The water mist flow rate is 10L / min per 10mm. The third stage is water quenching, with a water flow rate of 20L / min in the quenching water tank and a cooling rate controlled at 25℃ / s. Temperature after multi-stage quenching: ≤90℃; The stretching and straightening process has a stretching rate of 1.1%, and the surface is free of orange peel defects. The aging process is carried out at 180℃ for 9 hours.

4. The processing and forming method of the aluminum alloy boom structure according to claim 1, characterized in that, A large-section aluminum alloy profile and an integrated copper-aluminum composite bushing are connected using a high-strength connection process to obtain an aluminum alloy boom structure, including: After connecting the large-section aluminum alloy profile and the copper-aluminum integrated composite bushing with ring groove rivets, they are then connected by friction stir welding, forming a double composite connection.

5. The processing and forming method for the aluminum alloy boom structure according to claim 4, characterized in that, A large-section aluminum alloy profile and an integrated copper-aluminum composite bushing are connected using a high-strength connection process to obtain an aluminum alloy boom structure, including: The ring groove rivet is used for riveting connection. According to the structure and strength characteristics of the hollow thin-walled profile, rivet holes are opened on both sides of the profile and the composite bushing support plate. B-R10-8 rivets are selected in an array of 4×12. Friction stir welding is performed around the outer circumference of the composite bushing support plate, with three friction stir welds arranged along the profile extrusion direction at interval array rivets.

6. The processing and forming method of the aluminum alloy boom structure according to claim 1, characterized in that, Designing extrusion dies and completing their manufacturing and assembly, including: Punch installation: The punch mounting plate, upper template, core die, and extrusion punch are connected by bolts. The punch mounting plate is installed on the slider of the pressure equipment. The core die has a built-in heating resistance wire, which can realize the directional heating of the aluminum alloy billet. The extrusion punch has a built-in heating resistance wire, which realizes the directional heat preservation or heating of the aluminum alloy billet and copper alloy billet through the lower working surface. Die installation: The conical die and prestressed sleeve are installed on the prestressed pressure plate with bolts. The prestressed pressure plate and the lower template are connected by bolts without interfering with the operation of the side pressure cylinder. The lower template is installed on the pressure equipment workbench with bolts; the first guide plate is connected to the first side plate with bolts, and the second guide plate is connected to the second side plate with bolts; Insert the flow guide plate 1 and flow guide plate 2 from both sides of the bottom of the die cavity to complete the splicing without fixing; side pressure cylinder 1 and side pressure cylinder 2 respectively press side pressure plate 1 and side pressure plate 2 and lock them in place. By incorporating a heating resistance wire into the conical die, directional heating of the copper alloy billet can be achieved, including heating before and after forming. By incorporating a heating resistance wire into the prestressed sleeve, directional heat preservation or heating of the aluminum alloy layer on the outer side of the formed part can be achieved.

7. An aluminum alloy boom structure, manufactured by the method described in any one of claims 1-6.

8. A mold for machining and forming aluminum alloy boom structures, characterized in that, It includes a punch mounting plate, an upper template, a core mold, an extrusion punch, a prestressed pressure plate, a conical die, a prestressed sleeve, a side pressure cylinder one, a side pressure plate one, a flow guide plate one, a flow guide plate working blade, a lower template, a flow guide plate two, a side pressure plate two, and a side pressure cylinder two; The punch mounting plate, upper template, core die, and extrusion punch are connected by bolts, and the punch mounting plate is mounted on the slider of the pressure equipment; The core mold has a built-in heating resistance wire for directional heating of the aluminum alloy billet; The extrusion punch has a built-in heating resistance wire, which is used to achieve directional heat preservation or heating of aluminum alloy billets and copper alloy billets through the lower working surface; The conical mold and the prestressed sleeve are respectively installed on the prestressed pressure plate by bolts, and the prestressed pressure plate is connected to the lower template by bolts. The lower template is bolted to the worktable of the pressure equipment. The first flow guide plate is connected to the first side plate by bolts, and the second flow guide plate is connected to the second side plate by bolts; The flow guide plate one and the flow guide plate two are installed on the bottom side of the cone mold without being fixed. The first and second side pressure cylinders respectively press the first and second side pressure plates and lock them in place.

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