Solid phase welding method and aluminum steel composite connecting member

Abstract

This application relates to a solid-state welding method and an aluminum-steel composite connecting component. A solid-state welding method includes the following steps: using aluminum alloy as raw material, a stepped aluminum alloy transition deposition layer is deposited on the anode steel claw at the connection location using solid-state additive manufacturing to form an aluminum alloy transition deposition layer covering the surface of the connection location; the stepped structure of the aluminum alloy transition deposition layer is processed to reduce surface roughness; the aluminum guide rod to be connected is processed to form a mating structure matching the stepped structure; the anode steel claw and the aluminum guide rod are assembled, so that the stepped structure and the mating structure are tightly fitted, and the anode steel claw and the aluminum guide rod are fixed; the anode steel claw and the aluminum guide rod are friction-welded, causing the aluminum alloy at the interface between the stepped structure and the mating structure to undergo plastic deformation under continuous pressure and relative displacement, forming a composite interface joint, thereby creating a high-strength metallurgical interface and an integrated high-conductivity path from the source.

Description

Technical Field

[0001] This application relates to the field of solid-state bonding technology, and in particular to solid-state welding methods and aluminum-steel composite connecting components. Background Technology

[0002] With the global aluminum electrolysis industry's continuous pursuit of energy conservation, emission reduction, and production stability, the conductivity efficiency and mechanical reliability of the anode assembly, as the core component for current conduction, are of paramount importance. The dissimilar metal connection between the aluminum guide rod and the anode steel claw is a key link in achieving efficient and stable power transmission to the electrolytic cell, and its performance directly affects the DC power consumption per ton of aluminum during the electrolysis process and the safety of equipment operation.

[0003] For dissimilar metal connections between aluminum guide rods and steel claws, interfacial contact resistance and joint strength are two core indicators that determine their overall performance. Traditional techniques commonly employ a connection method involving aluminum guide rods, aluminum-steel composite transition blocks, and steel claws, secured by seam welding or riveting.

[0004] This technical approach has the following inherent drawbacks:

[0005] (1) Poor conductivity. The connection is essentially a multi-point or line contact with a small effective conductive area, resulting in high contact resistance and significant Joule heat loss under strong currents of tens of kiloamperes.

[0006] (2) Insufficient strength. The joint is prone to loosening or cracking under long-term thermal stress, electromagnetic force and hoisting stress, which poses a safety hazard.

[0007] (3) Complex process. Relying on prefabricated aluminum / steel composite transition blocks, such as explosive welding blocks, has a long production process, high cost, and introduces additional, potential failure interfaces.

[0008] Moreover, traditional technologies mostly focus on improving the composition of transition blocks or seam welding processes, thus failing to fundamentally change the inherent problems of low bonding strength and high contact resistance. Summary of the Invention

[0009] Therefore, it is necessary to provide a solid-state welding method and an aluminum-steel composite connecting component.

[0010] One embodiment of this application is a solid-state welding method, which includes the following steps:

[0011] Using aluminum alloy as raw material, a stepped aluminum alloy transition deposition layer is deposited on the connection position of the anode steel claw using solid-phase additive manufacturing to form an aluminum alloy transition deposition layer covering the surface of the connection position.

[0012] The stepped structure of the aluminum alloy transition deposition layer is processed to reduce surface roughness;

[0013] The aluminum guide rods to be connected are processed to form a mating structure that matches the stepped structure;

[0014] The anode steel claw is assembled with the aluminum guide rod so that the stepped structure and the mating structure fit tightly together, and the anode steel claw and the aluminum guide rod are fixed.

[0015] Friction welding is performed on the anode steel claw and the aluminum guide rod, causing the aluminum alloy at the interface where the stepped structure and the mating structure are in contact to undergo plastic deformation under continuous pressure and relative displacement, forming a composite interface joint.

[0016] The aforementioned solid-state welding method ingeniously forms an aluminum alloy transition deposition layer with a stepped structure, serving as an intermediate structure for the assembly of the anode steel claw and the aluminum guide rod. This provides a process flow for solid-state additive friction welding, eliminating the need for traditional aluminum-steel composite transition blocks and eliminating the need for independent transition components. It also removes multiple steps involved in prefabrication, procurement, storage, and assembly of independent transition blocks, achieving an innovative connection method for large-area metallurgical bonding of aluminum and steel. This fundamentally increases the effective conductive cross-section and strengthens the interfacial bonding, resulting in a synergistic leap forward in the joint's conductivity and mechanical properties. Therefore, it fundamentally overcomes the limitations of traditional aluminum-steel composite welding methods. This paper addresses the inherent defects of transition blocks, such as poor conductivity, insufficient strength, and complex manufacturing processes. It resolves issues in the electrolytic aluminum industry, including small interface bonding area, low joint bonding strength, and the complex and costly processes resulting from reliance on aluminum-steel composite transition blocks in the connection process between aluminum guide rods and anode steel claws. Furthermore, through an innovative process design, an aluminum alloy transition deposition layer is constructed in situ at the connection point of the anode steel claw, achieving a large-section metallurgical bond with the aluminum guide rod. This fundamentally creates a high-strength metallurgical interface and an integrated, highly conductive path, thereby improving the conductivity and mechanical load-bearing capacity of the composite interface joint. Performance provides key technical support for energy saving, consumption reduction, and safe operation of electrolytic cells; on the other hand, the use of solid-phase additive manufacturing technology to prepare an aluminum alloy transition deposition layer on the surface of the anode steel claw has the advantages of low process temperature and low heat input, avoiding the high thermal stress generated by fusion welding or explosive welding, relieving interfacial stress, and effectively inhibiting the formation of brittle intermetallic compounds. This results in a metallurgical transition interface with high bonding strength and low residual stress between the steel substrate and the aluminum alloy transition deposition layer, ensuring the reliability of the aluminum-steel composite connection from the source, and overcoming the tendency for interface failure in traditional aluminum-steel composite transition blocks. While addressing weaknesses, it also enhances the overall structural stability and reliability, which helps extend service life and reduce maintenance costs. Furthermore, by designing stepped and mating structures, the aluminum guide rod and the aluminum alloy transition deposition layer form a mutually compatible and even interlocking contact interface. Combined with friction welding technology, this achieves comprehensive solid-state metallurgical bonding, resulting in an effective contact area that is orders of magnitude larger than that of traditional seam welding point or line connections. This directly leads to a sharp reduction in interface contact resistance, which significantly reduces Joule heat loss under the high current conditions of electrolytic production, thus achieving the core function of reducing production energy consumption.

[0017] As an example, depositing an aluminum alloy transition layer with a stepped structure at the connection position of the anode steel claw includes: depositing a first aluminum alloy transition layer of a predetermined thickness at the connection position of the anode steel claw to cover the connection position surface; and continuing to deposit a second aluminum alloy transition layer with a stepped structure on the first aluminum alloy transition layer.

[0018] As an example, the stepped structure and the mating structure are interlocked; or, the stepped structure and the mating structure form at least two interlocking contact interfaces that are radially distributed in the assembly direction.

[0019] As an example, before depositing an aluminum alloy transition deposition layer with a stepped structure covering the surface of the anode steel claw at the connection location, the solid-state welding method further includes the step of: performing a silicon enrichment treatment on the surface of the connection location to form a silicon-containing surface with a thickness of 5 μm to 500 μm.

[0020] In some embodiments, after the friction welding is completed, the solid-state welding method further includes the steps of: rapidly increasing axial pressure to achieve upsetting, so that the composite interface joint completes crystallization and preliminary cooling and shaping under pressure, and then the pressure is removed.

[0021] In some embodiments, prior to the friction welding, the solid-state welding method further includes the step of: premixing surface-metallized carbon nanomaterials into the interface to be bonded at least one of the stepped structure and the mating structure to construct additional conductive pathways.

[0022] In some embodiments, the step structure includes annular step structures and rectangular step structures.

[0023] In some embodiments, the stepped structure is cylindrical or cylindrical.

[0024] In some embodiments, the diameter of the stepped structure is 100 mm to 600 mm; the wall thickness is 10 mm to 50 mm; and the height is 10 mm to 20 mm.

[0025] In some embodiments, the aluminum alloy transition deposition layer, in addition to the stepped structure, has a preset thickness of 10 mm to 20 mm; or, the preset thickness is set according to the shape and size of the surface at the location to be connected; or, the protrusion height of both the stepped structure and the mating structure is 20 mm to 60 mm.

[0026] In some embodiments, the solid-state additive manufacturing method includes at least one of continuous wire feeding friction stir additive manufacturing, friction stir deposition, solid-state deformation driven deposition, and friction surfacing.

[0027] In some embodiments, the friction welding includes at least one of rotary friction welding, linear friction welding, and inertial friction welding.

[0028] In some embodiments, an aluminum-steel composite connecting member is prepared using the solid-state welding method described in any embodiment. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic flowchart of an embodiment of the solid-state welding method described in this application.

[0031] Figure 2 This is a structural schematic diagram of an embodiment of the aluminum-steel composite connecting member described in this application.

[0032] Figure 3 for Figure 2 Another schematic diagram of the embodiment shown.

[0033] Figure 4 This is a structural schematic diagram of another embodiment of the aluminum-steel composite connecting member described in this application.

[0034] Figure 5 for Figure 4 Another schematic diagram of the embodiment shown.

[0035] Reference numerals: 1. Aluminum guide rod; 2. Anode steel claw; 3. Aluminum alloy transition deposition layer; 31. First aluminum alloy transition layer; 32. Second aluminum alloy transition layer. Detailed Implementation

[0036] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0037] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application's specification are for illustrative purposes only and do not represent the only possible implementation.

[0038] 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 at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0039] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is 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 can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0040] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0041] In one embodiment of this application, a solid-state welding method is provided, such as... Figure 1 As shown, the process includes the following steps: using aluminum alloy as raw material, a stepped transition deposition layer is deposited on the anode steel claw at the connection location using solid-phase additive manufacturing to form an aluminum alloy transition deposition layer covering the surface of the connection location; the stepped structure of the aluminum alloy transition deposition layer is processed to reduce surface roughness; the aluminum guide rod to be connected is processed to form a mating structure that matches the stepped structure; the anode steel claw and the aluminum guide rod are assembled to ensure a tight fit between the stepped structure and the mating structure, and to fix the anode steel claw and the aluminum guide rod; the anode steel claw and the aluminum guide rod are friction welded to allow the aluminum alloy at the interface between the stepped structure and the mating structure to undergo plastic deformation under continuous pressure and relative displacement, forming a composite interface joint.

[0042] This design cleverly creates a stepped aluminum alloy transition deposition layer, serving as an intermediate structure for the assembly of the anode steel claw and the aluminum guide rod, providing a solid-state additive manufacturing process for friction welding. On one hand, it eliminates the need for traditional aluminum-steel composite transition blocks, removing the need for independent transition components and saving multiple steps in prefabrication, procurement, storage, and assembly of independent transition blocks. This achieves an innovative connection method for large-area metallurgical bonding of aluminum and steel. At its core, it increases the effective conductive cross-section and strengthens the interface bonding, achieving a synergistic leap in the joint's conductivity and mechanical properties. Therefore, it fundamentally overcomes the inherent defects of traditional aluminum-steel composite transition blocks, such as poor conductivity, insufficient strength, and complex processes. It also solves problems in the electrolytic aluminum industry, such as small interface bonding area, low joint bonding strength, and the complex processes and high costs resulting from reliance on aluminum-steel composite transition blocks during the connection of aluminum guide rods and anode steel claws.

[0043] On the other hand, through an innovative process design, an aluminum alloy transition deposition layer is constructed in situ at the connection position of the anode steel claw, and a large-section metallurgical bond is achieved with the aluminum guide rod. This creates a high-strength metallurgical interface and an integrated high-conductivity path at the source, thereby improving the conductivity and mechanical load-bearing capacity of the composite interface joint, and providing key technical support for the energy saving, consumption reduction and safe operation of the electrolytic cell.

[0044] On the other hand, the use of solid-phase additive manufacturing technology to prepare an aluminum alloy transition deposition layer on the surface of the anode steel claw has the advantages of low process temperature and low heat input, avoiding the high thermal stress generated by fusion welding or explosive welding. While relieving interfacial stress, it can effectively inhibit the formation of brittle intermetallic compounds, thereby forming a metallurgical transition interface with high bonding strength and low residual stress between the steel substrate and the aluminum alloy transition deposition layer. This ensures the reliability of the aluminum-steel composite connection from the source, overcomes the weakness of easy failure of the interface of traditional aluminum-steel composite transition blocks, and improves the stability and reliability of the overall structure, which is conducive to extending service life and reducing maintenance costs.

[0045] On the other hand, by designing stepped and mating structures, the aluminum guide rod and the aluminum alloy transition deposition layer form a contact interface that matches and even interlocks with each other. Combined with friction welding technology, a comprehensive solid-state metallurgical bond is achieved, which increases the effective contact area by orders of magnitude compared to the point or line connection of traditional seam welding. This directly leads to a sharp reduction in interface contact resistance. In this way, under the high current conditions of electrolytic production, the resulting Joule heat loss is significantly reduced, achieving the core role of reducing production energy consumption.

[0046] As an example, the materials for the anode steel claws include, but are not limited to, non-alloy steel, low-alloy steel, alloy steel, and stainless steel; the structure of the steel claws includes, but is not limited to, eight-claw steel claws and four-claw steel claws. In order to control production costs and process stability, Q235 carbon structural steel can be used as raw material. Those skilled in the art will understand that this is an example and not a limitation, and will not be repeated below.

[0047] The surface to be connected is the surface of the location to be connected. Since it is a deposition process, it can also be called the deposition surface.

[0048] To further improve the bonding strength of the aluminum-steel interface, as an example, before depositing an aluminum alloy transition deposition layer with a stepped structure covering the surface of the anode steel claw at the connection location, the solid phase welding method further includes the step of grinding and cleaning the anode steel claw surface to be deposited to remove the oxide layer, oil, and dust from the surface to be deposited.

[0049] As an example, before depositing an aluminum alloy transition deposition layer with a stepped structure covering the surface of the anode steel claw at the connection location, the solid-state welding method further includes the step of: performing a silicon enrichment treatment on the surface of the connection location to form a silicon-containing surface with a thickness of 5 μm to 500 μm, that is, forming a Si-containing microlayer on the deposition surface to improve the interfacial reaction between aluminum and steel.

[0050] This design, on the one hand, effectively removes the original oxide layer, oil, and dust impurities from the surface to be deposited by treating the connection points of the anode steel claws. This treatment eliminates the contact resistance risks caused by interfacial contaminants, ensuring the physical adhesion between the aluminum alloy transition deposition layer and the anode steel claw substrate, laying a clean and uniform foundation interface for subsequent direct atomic diffusion bonding. On the other hand, the formation of a Si-containing microlayer on the surface plays a crucial role in regulating the interfacial reaction. Silicon, as an excellent surface modifier, preferentially migrates to and accumulates at the aluminum-steel interface under the thermal effects of solid-state welding. By forming a low-melting-point eutectic liquid phase, the silicon layer effectively reduces the atomic diffusion activation energy during welding, inhibiting the formation of brittle Fe-Al intermetallic compounds. Furthermore, the stepped structure of the silicon-containing transition layer provides an excellent anchoring effect for the aluminum alloy deposition layer, greatly enhancing the shear strength and thermal shock resistance of the aluminum-steel interface through a dual mechanism of physical interlocking and metallurgical bonding. On the other hand, the aforementioned pretreatment steps synergistically optimize interface cleanliness, reaction compatibility, and bonding mechanical strength, thereby significantly improving the overall connection quality and service life of the anode steel claw and the aluminum alloy deposit layer.

[0051] In the embodiments of this application, aluminum alloy is used as the raw material, and a stepped aluminum alloy transition deposition layer is deposited on the anode steel claw at the connection position using solid-state additive manufacturing to form an aluminum alloy transition deposition layer covering the surface of the connection position. This innovative process route allows for the in-situ construction of a high-performance aluminum alloy transition deposition layer at the connection end of the anode steel claw, and facilitates a large-section metallurgical bond with the aluminum guide rod. This fundamentally creates a high-strength metallurgical interface and an integrated high-conductivity path, simultaneously improving the conductivity and mechanical load-bearing capacity of the joint, providing key technical support for energy saving, consumption reduction, and safe operation of the electrolytic cell.

[0052] As an example, the materials selected for the aluminum alloy transition deposition layer include pure Al, Al-Si alloy, Al-Mg-Si alloy, etc. The thermoplasticization and deposition process is achieved through frictional heat and large plastic deformation between the aluminum alloy and the steel plate surface of the anode claw. A dense aluminum alloy transition deposition layer is obtained with a single-layer deposition thickness of 1.0 mm to 2.0 mm and a deposition efficiency of 0.5 kg / h to 3 kg / h. In some embodiments, the solid-state additive manufacturing method includes at least one of continuous wire feeding friction stir additive manufacturing, friction stir deposition, solid-state deformation driven deposition, and friction welding. This eliminates the need for an additional third-party transition aluminum-steel block, allowing the formation of an aluminum alloy transition deposition layer on the surface of the anode claw at the connection location. Therefore, a large-area metallurgical bond between aluminum and steel can be achieved without an independent transition component, fundamentally increasing the effective conductive cross-section, strengthening the interfacial bonding, significantly reducing the resistance of the anode device, lowering energy consumption during production and use, and achieving a synergistic leap in the conductivity and mechanical properties of the joint. This provides fundamental technical support for efficient, low-carbon, and safe production in the electrolytic aluminum industry.

[0053] In some embodiments, the aluminum alloy transition deposition layer has a predetermined thickness, except for the stepped structure. As an example, depositing an aluminum alloy transition deposition layer with a stepped structure covering the surface of the anode claw at the connection location includes: depositing a first aluminum alloy transition layer of predetermined thickness at the connection location of the anode claw, covering the surface of the connection location; and continuing to deposit a second aluminum alloy transition layer with a stepped structure on the first aluminum alloy transition layer. In some embodiments, the predetermined thickness is 10 mm to 20 mm; or in some embodiments, the predetermined thickness is set according to the shape and size of the surface of the connection location. As an example, depending on the shape and size of the surface to be deposited, an aluminum alloy transition deposition layer of 10 mm to 20 mm thickness is deposited, covering the entire surface to be deposited.

[0054] This design, on the one hand, firstly deposits a first aluminum alloy transition layer with a preset thickness of 10mm to 20mm to completely cover the surface of the anode steel claw to be connected. This achieves uniform coverage and effective transition of the steel substrate surface, adapting to the shape and size characteristics of the surface to be deposited. It ensures sufficient bonding between the transition layer and the steel substrate, without any local weak areas, providing a flat and firmly bonded base for subsequent stepped structure forming, avoiding problems such as uneven thickness and weak bonding that are prone to occur in single-layer deposition. On the other hand, a second aluminum alloy transition layer with a stepped structure is deposited on the first aluminum alloy transition layer. This allows for precise construction of a connection interface that matches the structure of the aluminum guide rod, improving assembly fit and connection positioning accuracy. Furthermore, the layered deposition process retains the advantages of low temperature and low heat input of solid-state additive manufacturing, avoiding the formation of high thermal stress and brittle intermetallic compounds, and strengthening the bonding strength of the aluminum-steel metallurgical transition interface. On the other hand, the thickness setting of 10mm to 20mm takes into account both structural strength and conductivity requirements. The full-coverage deposition further expands the effective conductive cross section, synergistically improves the mechanical properties and conductivity efficiency of the joint, reduces the interface contact resistance and Joule heat loss, optimizes the joint operation stability under electrolytic aluminum conditions, extends service life and effectively reduces maintenance costs.

[0055] In some embodiments, the stepped structure includes annular stepped structures and rectangular stepped structures. In some embodiments, the stepped structure is cylindrical or cylindrical; in some embodiments, the diameter of the stepped structure is 100mm to 600mm and the wall thickness is 10mm to 50mm; or in some embodiments, the diameter of the stepped structure is 100mm to 600mm and the height is 10mm to 20mm. As an example, depending on the shape and size of the aluminum guide rod, a stepped structure with an equivalent diameter of 100mm to 600mm, a wall thickness of 10mm to 50mm, and a height of 10mm to 20mm is further deposited on the aluminum alloy transition deposition layer. It is understood that the specific parameters such as diameter, wall thickness, and height can be set or adjusted according to the shape and size of the aluminum guide rod, and the embodiments of this application do not impose additional limitations in this regard. As an example, solid-phase additive manufacturing is used to prepare full-area aluminum alloy transition deposition layers with a thickness of 10 mm to 20 mm and annular or rectangular stepped structures with a wall thickness of 10 mm to 50 mm, an equivalent diameter of 100 mm to 600 mm, and a height of 10 mm to 20 mm using wire, plate, or rod as raw materials.

[0056] This design offers several advantages. First, the diverse stepped structure forms and standardized dimensional parameters allow for precise matching of different specifications of aluminum guide rods, achieving efficient positioning and tight fit during assembly, significantly improving interface bonding accuracy and assembly stability. Second, the optimized parameter design maximizes the effective contact area while ensuring structural strength, providing a reliable structural foundation for subsequent friction welding to form a large-area metallurgical bond. Third, the solid-state additive manufacturing method retains the advantages of low temperature and low heat input, avoiding high thermal stress and the formation of brittle intermetallic compounds, ensuring a uniform and dense bond between the aluminum alloy transition deposition layer and the stepped structure. Fourth, the above design, through multi-dimensional synergistic optimization of structural form, dimensional parameters, and manufacturing process, significantly increases the effective conductive cross-section of the aluminum-steel interface, reduces contact resistance and Joule heat loss, and simultaneously improves the mechanical load-bearing capacity and conductivity of the joint, providing solid structural support for energy saving, consumption reduction, and long-term stable operation of electrolytic aluminum equipment.

[0057] In each embodiment, the stepped structure of the aluminum alloy transition deposition layer is processed to reduce surface roughness; as an example, the stepped structure of the aluminum alloy transition deposition layer is milled to reduce surface roughness, making the stepped shape of the aluminum alloy transition deposition layer regular and having higher shape accuracy, so as to facilitate plastic deformation with the mating structure in the subsequent friction welding process.

[0058] This design offers several advantages. First, milling efficiently removes rough protrusions and microscopic defects from the stepped structure surface, resulting in a more uniform and regular step shape with significantly improved dimensional and positional accuracy. This ensures a precise match between the stepped structure and the aluminum guide rod, achieving seamless fit and stable positioning during assembly and avoiding gaps and misalignments caused by surface roughness or shape deviations. Second, the low-roughness, regular interface can be used in subsequent friction welding, allowing for more uniform stress distribution and smoother plastic flow in the aluminum alloy at the interface. This enables rapid and stable plastic deformation under continuous pressure and relative displacement, effectively improving the quality and density of the composite interface joint. Third, the regular, fitted interface further expands the aluminum-steel metallurgical bonding area, reducing interfacial contact resistance and effectively suppressing the formation of brittle intermetallic compounds caused by localized stress concentration and high heat input. This also enhances the joint's mechanical properties and electrical conductivity.

[0059] To increase the contact area and tensile strength between the aluminum guide rod and the anode steel claw joint, in various embodiments, the aluminum guide rod to be connected is machined to form a mating structure that matches the stepped structure. Then, the anode steel claw is assembled with the aluminum guide rod, ensuring a tight fit between the stepped structure and the mating structure, and fixing the anode steel claw and the aluminum guide rod. As an example, the aluminum guide rod is machined to form a rectangular or cylindrical mating structure with an equivalent diameter ranging from 100mm to 600mm and a machining depth of 10mm to 20mm, allowing it to fit tightly with the stepped structure of the aluminum alloy transition deposition layer. As an example, one side of the aluminum guide rod is machined or milled to form a mating structure that interlocks with the interface of the aluminum alloy transition deposition layer. In some embodiments, the protrusion height of both the stepped structure and the mating structure is 20mm to 60mm. As an example, the stepped structure and the mating structure have complementary shapes to form sufficient surface contact. As an example, the stepped structure and the mating structure are interlocked. As an example, the stepped structure and the mating structure form at least two interlocking contact interfaces radially distributed in the assembly direction.

[0060] This design, on the one hand, allows for the formation of rectangular or cylindrical mating structures within a preset parameter range on the aluminum guide rod through machining or milling. This enables high-precision adaptation to the stepped structure of the aluminum alloy transition deposition layer. The mating structure and the stepped structure employ complementary shapes to form a mutually interlocking state, creating a full and stable surface contact state. This completely abandons the traditional point or line contact mode, resulting in an order-of-magnitude increase in the effective bonding area. On the other hand, the effective cooperation between the stepped structure and the mating structure significantly improves the overall mechanical interlocking capacity and mechanical load-bearing performance of the joint, significantly enhancing the joint's tensile, shear, and fatigue strength, effectively preventing failures such as loosening and detachment during service. Furthermore, the tight fit and multi-layered interlocking interface morphology promotes uniform plastic flow and full diffusion of the aluminum alloy during subsequent friction welding, forming a dense and stable metallurgical bonding interface, reducing interfacial contact resistance and Joule heat loss, and inhibiting the formation of brittle intermetallic compounds and local stress concentration.

[0061] To improve the conductivity of the bonding interface, in some embodiments, before friction welding, the solid-state welding method further includes the step of: premixing surface-metallized carbon nanomaterials into the bonding interface of at least one of the stepped structure and the mating structure to construct additional conductive pathways; that is, a trace amount of surface-metallized carbon nanomaterials may be premixed into the bonding interface to construct additional conductive pathways.

[0062] This design offers several advantages. First, the surface-metallized carbon nanomaterials can be uniformly dispersed at the interface to be joined. Leveraging their high conductivity and two-dimensional network structure, they create a continuous and stable additional conductive path in situ at the aluminum-steel composite interface, effectively compensating for weak points in local conductivity at traditional joint interfaces, further reducing interfacial contact resistance, and significantly improving the overall conductivity efficiency of the bonding interface. Second, surface metallization modification significantly improves the wettability and compatibility between the carbon nanomaterials and the aluminum alloy matrix, avoiding interfacial agglomeration or poor bonding, and ensuring long-term stability of the conductive path. Third, under high-current conditions in aluminum electrolysis, this design can significantly reduce Joule heat loss, enhance the uniformity of joint conductivity, and simultaneously maintain the plastic deformation and metallurgical bonding of the aluminum alloy during friction welding, balancing high conductivity and high mechanical properties. Finally, this method, from the perspective of interfacial conductivity optimization, further improves the conductivity of the composite interface joint, thus providing stronger support for the efficient, energy-saving, and stable operation of the electrolytic cell.

[0063] In each embodiment, the anode steel claw and the aluminum guide rod are friction welded, causing the aluminum alloy at the interface between the stepped structure and the mating structure to undergo plastic deformation under continuous pressure and relative displacement, forming a composite interface joint. In some embodiments, the friction welding includes at least one of rotary friction welding, linear friction welding, and inertial friction welding, with appropriate friction welding methods used for different step forms and different anode steel claw structures.

[0064] This design offers several advantages. First, friction welding achieves interfacial bonding through solid-state connection, maintaining the advantages of low process temperature and low heat input. This effectively suppresses the formation of brittle intermetallic compounds, alleviates residual stress at the interface, and ensures a dense and reliable metallurgical bond between the aluminum and steel interfaces. Second, selecting a suitable friction welding method allows for flexible matching of the optimal welding scheme to different step forms and anode claw structures. This ensures uniform and sufficient plastic deformation of the interface under different structural configurations, achieving a stable connection with large cross-sections and high fit. Third, the aforementioned process enhances the mechanical load-bearing capacity of the composite interface joint while further reducing interfacial contact resistance and improving conductivity. This benefits the joint's long-term stable operation from both process adaptability and interfacial bonding quality perspectives.

[0065] In some embodiments, after friction welding, the solid-state welding method further includes the step of rapidly increasing axial pressure to achieve upsetting, allowing the composite interface joint to complete crystallization and preliminary cooling and shaping under pressure, and then releasing the pressure. As an example, the aluminum guide rod and anode steel claw are assembled, and the stepped structure is tightly fitted with the mating structure before being fixed. Then, one side of the aluminum guide rod and anode steel claw is fixed, while the other side undergoes plastic deformation of the interface under continuous pressure and relative displacement. The displacement is then quickly stopped, and the axial pressure is rapidly increased to achieve upsetting. The upsetting pressure is then maintained for 5 to 25 seconds, allowing the joint to complete crystallization and preliminary cooling and shaping under pressure, and then the pressure is released, thereby achieving a high-strength connection between the aluminum guide rod and the anode steel claw.

[0066] This design, on the one hand, effectively prevents excessive heat input to the interface region after plastic deformation and full diffusion at the friction welding interface, rapidly controlling the thermal cycle during friction welding and avoiding excessive thickening of the brittle intermetallic compound layer caused by local overheating of the joint. This maintains the excellent state of a dense, fine, and uniform joint structure. On the other hand, maintaining the joint under upsetting pressure for a certain period of time allows the high-pressure environment to provide thermodynamic driving force for the diffusion and crystallization of interface atoms, promoting orderly crystallization and solid-phase reorganization in the interface region under pressure constraint, achieving densification and strength enhancement of the metallurgical bonding interface. Furthermore, preliminary cooling and shaping under certain pressure effectively eliminates residual stress and microcrack risks inside the joint, ensuring that the joint structure maintains high dimensional stability and mechanical integrity after depressurization. Moreover, the precise coordination between the above-mentioned upsetting process and the main friction welding process fundamentally improves the tensile strength, impact toughness, and long-term operational reliability of the joint, providing key process support for the high-strength, long-life connection of the anode steel claw and aluminum guide rod.

[0067] The following examples illustrate solid-state welding methods. In some embodiments, a solid-state welding method includes the following steps.

[0068] The first step involves the preparation of the aluminum alloy transition deposition layer. Using aluminum alloy as the raw material, a solid-state additive manufacturing method is employed to deposit an aluminum alloy transition deposition layer with annular or rectangular step structure on the surface of the anode steel claw. Depending on the shape and size of the surface to be deposited, an aluminum alloy transition deposition layer with a thickness of 10 mm to 20 mm is deposited, covering the entire surface. Furthermore, depending on the shape and size of the aluminum guide rod, a step structure with a diameter of 100 mm to 600 mm and a wall thickness of 10 mm to 50 mm is deposited on the aluminum alloy transition deposition layer. The step shape includes, but is not limited to, annular or rectangular steps.

[0069] Secondly, the stepped structure and aluminum guide rod processing are addressed. The stepped structure of the aluminum alloy transition deposition layer is milled to reduce surface roughness. One side of the aluminum guide rod is machined or milled to form a mating structure. The mating structure can interlock and fit with the interface of the aluminum alloy transition deposition layer. The protrusion height of the mating structure of the aluminum guide rod and the protrusion height of the stepped structure of the aluminum alloy transition deposition layer on the anode steel claw are both 20mm to 60mm.

[0070] Finally, the aluminum guide rod and the anode steel claw are welded. Since the aluminum guide rod is made of aluminum alloy, and the aluminum alloy transition deposition layer on the anode steel claw is also made of aluminum alloy, welding the aluminum guide rod and the anode steel claw is reliable, easy, and straightforward. The aluminum guide rod and the anode steel claw are assembled, and after the two stepped structures are tightly fitted, they are fixed. Friction welding is used to cause plastic deformation of the aluminum alloy at the interface under continuous pressure and relative displacement, achieving atomic bonding. After quickly stopping rotation or displacement, the axial pressure is rapidly increased to achieve upsetting, and the pressure is held for 5 to 25 seconds, allowing the joint to complete crystallization and initial cooling and shaping under pressure. Then the pressure is released, resulting in a fully bonded joint.

[0071] This design employs solid-state additive manufacturing technology to prepare an aluminum alloy transition deposition layer on the surface of the anode steel claw. This process involves low temperature and low heat input, avoiding the high thermal stress generated by fusion welding or explosive welding. While alleviating interfacial stress, it effectively inhibits the formation of brittle intermetallic compounds, thus forming a metallurgical transition interface with high bonding strength and low residual stress between the steel substrate and the aluminum alloy transition deposition layer. This ensures the reliability of the aluminum-steel layer connection from the source and overcomes the weakness of traditional aluminum-steel composite transition block interfaces prone to failure. Furthermore, by designing an annular stepped staggered bonding structure, a radially distributed, multi-layered interlocking contact interface is formed between the aluminum guide rod and the aluminum alloy transition deposition layer. Under subsequent friction welding, these interfaces achieve comprehensive solid-state metallurgical bonding, with an effective contact area order of magnitude larger than that of traditional seam welding point / line connections. This directly leads to a sharp reduction in interfacial contact resistance, significantly reducing Joule heat loss under the high current conditions of electrolytic production, achieving the core objective of reducing production energy consumption. Furthermore, not only does friction welding achieve metallurgical bonding of the aluminum / aluminum interface at the microscopic level, but it also innovatively introduces a stepped structure with interlocking fit at the macroscopic level. This mortise-and-tenon-like interlocking structure provides excellent assembly positioning before welding and forms a three-dimensional mechanical self-locking effect after welding. It complements the metallurgical bonding of friction welding, jointly bearing shear, tensile, and torsional loads, fundamentally improving the overall tensile strength, peel resistance, and vibration fatigue resistance of the joint. Moreover, the solid-state additive manufacturing combined with friction welding process replaces the complex traditional aluminum-steel composite transition block, multi-component alignment, and seam welding connection. Through in-situ additive manufacturing, functional layers are directly constructed on the steel claws, eliminating multiple steps of prefabrication, procurement, storage, and assembly of independent transition blocks. The resulting integrated joint structure of the steel claws, additive layer, and guide rod is compact and highly reliable, simplifying the production and assembly process of the anode assembly and improving its overall structural integrity, laying the foundation for extended service life and reduced maintenance costs.

[0072] In some embodiments, an aluminum-steel composite connecting member is prepared using any of the solid-state welding methods described in the embodiments. As an example, the aluminum-steel composite connecting member is an anode assembly having an anode steel claw and an aluminum guide rod, with an aluminum alloy transition deposition layer deposited on the anode steel claw, and the aluminum guide rod connecting to the aluminum alloy transition deposition layer. It is understood that, due to the use of any of the solid-state welding methods described in the embodiments, the aluminum-steel composite connecting member also possesses the beneficial technical effects of the solid-state welding method, which will not be elaborated upon here.

[0073] In some embodiments, the aluminum-steel composite connecting component before assembly is as follows: Figure 2 As shown, an aluminum alloy transition deposition layer 3 with a stepped structure is pre-deposited on the anode steel claw 2, and the aluminum guide rod 1 has a mating structure that matches the stepped structure; combined with Figure 3A first aluminum alloy transition layer 31 of a predetermined thickness is deposited at the connection position of the anode steel claw 2, covering the surface of the connection position; then, a second aluminum alloy transition layer 32 with a stepped structure is deposited on the first aluminum alloy transition layer 31. In this embodiment, the stepped structure is an annular stepped structure, which can also be understood as the stepped structure being cylindrical, and correspondingly, the mating structure is a cylinder that matches the cylindrical body. In some embodiments, the aluminum-steel composite connecting component before assembly is as follows: Figure 4 and Figure 5 As shown, with Figure 2 The difference in the illustrated embodiment is that the step structure is a rectangular step structure, and the mating structure is a shape that matches the rectangular step structure. In other embodiments, the mating structure is a frustum; or the step structure is a frustum; or the step structure is a two-stage step structure; and so on.

[0074] In some embodiments, the aluminum-steel composite connecting component has a high-strength joint between an aluminum guide rod and an anode steel claw. Specifically, the aluminum-steel composite connecting component includes an aluminum guide rod, an anode steel claw, and an aluminum alloy transition deposition layer. The aluminum alloy transition deposition layer on the anode steel claw is made from pure Al, Al-Si alloy, Al-Mg-Si alloy, etc., and is achieved through solid-state additive manufacturing methods, such as continuous wire feeding friction stirring additive manufacturing, friction stirring deposition, solid-state deformation driven deposition, and friction welding. It is understood that pure Al theoretically contains trace amounts of other elements, so it can essentially also be called an aluminum alloy, that is, it is made from aluminum alloy and achieved through solid-state additive manufacturing methods. The aluminum guide rod is connected to the aluminum alloy transition deposition layer through friction welding methods, such as rotary friction welding, linear friction welding, and inertial friction welding. Finally, a high-strength, low-resistance aluminum-steel composite connecting component is obtained, which in this embodiment can also be called an aluminum guide rod and anode steel claw composite structure.

[0075] This application provides various embodiments of a high-strength solid-state welding method applicable to aluminum guide rods and anode steel claws, and aluminum-steel composite connecting components prepared using this method. The solid-state welding method mainly includes three major processes: preparation of an aluminum alloy transition deposition layer, processing of stepped structures, and friction welding. An aluminum alloy transition deposition layer is deposited in situ on the surface of the steel claw using solid-state additive manufacturing technology, and annular or rectangular stepped structures are designed. Combined with rotational, linear, or inertial friction welding, a large-area metallurgical bond at the aluminum-steel interface is achieved. Compared to the traditional process relying on aluminum-steel composite transition blocks and seam welding, this method forms a dual strengthening mechanism of high-strength metallurgical interface and three-dimensional mechanical interlocking, significantly improving the tensile strength and conductivity of the joint. Furthermore, the staggered fit design of the stepped structure and mating structure significantly increases the effective contact area, thereby greatly reducing interfacial contact resistance and Joule heat loss in electrolytic aluminum production. The integrated additive manufacturing and welding process eliminates the need for a third-party transition block, simplifies assembly, and reduces manufacturing costs. Therefore, it effectively solves the bottleneck problems of small joint area, low strength, high resistance, and complex processes in existing technologies. The following examples illustrate solid-state welding methods and aluminum-steel composite connection components in practical applications.

[0076] Example 1: The solid-state welding method includes the following steps.

[0077] Preparation of aluminum alloy transition deposition layer: The surface of the eight-claw anode steel claw made of Q235 material is polished and cleaned to remove the oxide layer and contaminants on the surface to be deposited. Using pure aluminum wire with a diameter of Φ2.4mm as raw material, a continuous wire feeding friction stirring additive manufacturing method is adopted. At a rotation speed of 400rpm to 1200rpm and a travel speed of 200mm / min to 600mm / min, a single layer deposition thickness of 1mm is achieved, depositing an aluminum alloy transition deposition layer of 300mm×300mm×14mm on the surface of the anode steel claw. On this basis, an annular stepped surface with a diameter of Φ300mm, a height of 10mm, and a wall thickness of 25mm is deposited, as shown. Figure 2 and Figure 3 As shown.

[0078] Machining of the stepped structure and aluminum guide rod: The inner wall and upper surface of the stepped structure of the aluminum alloy transition deposition layer are milled at a speed of 1000 rpm to 2500 rpm. The inner wall of the annular stepped structure is machined to a diameter of 290 (+0.1 to +0.3) mm and the step height is machined to 10 (-0.1 to -0.3) mm. One side of the aluminum guide rod is turned into a cylinder with a diameter of Φ290 (-0.2 to 0) mm as a mating structure. The cylinder height is 10 (-0.2 to -0.3) mm to achieve a tight fit between the cylindrical end of the aluminum guide rod and the stepped structure of the aluminum alloy transition deposition layer.

[0079] Welding of the aluminum guide rod and anode steel claw: After assembling the aluminum guide rod and anode steel claw to ensure a tight fit between the stepped structure and the mating structure, one side of the aluminum guide rod is fixed. A rotary friction welding method is used, with a rotation speed of 300 rpm to 1500 rpm, a pressure of 20 MPa to 100 MPa, a friction time of 5 to 15 seconds, and a forging pressure of 40 MPa to 160 MPa. This causes the aluminum alloy at the interface to undergo plastic deformation under continuous pressure and relative displacement, achieving interatomic bonding. The forging process is held at pressure for 10 seconds to allow the joint to complete crystallization and initial cooling and shaping under pressure. Then, the pressure is released, resulting in a fully bonded joint.

[0080] Example 2, the solid-state welding method includes the following steps.

[0081] Preparation of aluminum alloy transition deposition layer: The surface of the four-claw anode steel claws made of Q335 material is polished and cleaned to remove the oxide layer and contaminants on the surface to be deposited. Using a hot-dip galvanizing method with Φ8mm diameter 4043 aluminum alloy rods as raw material, a friction stir deposition additive manufacturing method is employed. At a rotation speed of 300rpm to 800rpm and a travel speed of 200mm / min to 600mm / min, a single-layer deposition thickness of 2mm is achieved, depositing a 150mm×300mm×14mm aluminum alloy transition deposition layer on the anode steel claw surface. A rectangular stepped surface with a diameter of 150mm×150mm×20mm is then deposited on top of this layer. Figure 4 and Figure 5 As shown.

[0082] Machining of the stepped structure and aluminum guide rod: The stepped structure of the aluminum alloy transition deposition layer is milled at a speed of 1000rpm to 2500rpm, and the height of the rectangular stepped structure is machined to 10 (-0.1 to -0.3)mm. A 150mm×150mm rectangular structure is machined on one side of the aluminum guide rod as a mating structure, with a step height of 10 (-0.2 to -0.3)mm, to achieve a tight fit between the aluminum guide rod and the aluminum alloy transition deposition layer.

[0083] The aluminum guide rod and anode steel claws are assembled to ensure a tight fit between the stepped structure and the mating structure. One side of the aluminum guide rod is then fixed. A linear friction welding method is used, with vibration frequencies ranging from 50Hz to 200Hz, vibration amplitudes from 1mm to 5mm, friction pressures from 20MPa to 80MPa, and forging pressures from 40MPa to 160MPa. This causes the aluminum alloy at the interface to undergo plastic deformation under continuous pressure and relative displacement, achieving interatomic bonding. The forging process is held at pressure for 10 seconds, allowing the joint to crystallize and undergo initial cooling and shaping under pressure. The pressure is then released, resulting in a fully bonded joint.

[0084] Example 3, the solid-state welding method includes the following steps.

[0085] Preparation of aluminum alloy transition deposition layer: The surface of the 15CrMo box-type anode steel claw is polished and cleaned to remove the oxide layer and contaminants on the surface to be deposited. A hot-dip galvanizing method is used with Al-Si plating. The temperature is heated to 750℃ to 800℃ at a rate of 5℃ / s to 20℃ / s and held for 80s to 150s. Then, it is cooled to the immersion temperature of 0℃ to 5℃ or higher at a rate of 5℃ / s to 20℃ / s before immersion plating begins. After immersion plating, it is cooled to room temperature at a rate of 10℃ / s to 25℃ / s to achieve the preparation of a Si-rich microlayer. Using 3mm thick 6082 aluminum alloy sheet as raw material, a friction stir additive manufacturing method is used to deposit a 260mm×260mm×12mm aluminum alloy transition deposition layer on the anode steel claw surface at a rotation speed of 600rpm to 1000rpm and a travel speed of 100mm / min to 300mm / min. A 260mm diameter, 10mm high annular stepped surface is then deposited on this layer.

[0086] Machining of the stepped structure and aluminum guide rod: At a speed of 1000rpm to 2500rpm, the inner wall and upper surface of the stepped structure of the aluminum alloy transition deposition layer are milled to a diameter of 250 (+0.1 to +0.3)mm and a step height of 10 (-0.1 to -0.3)mm. One side of the aluminum guide rod is turned into a cylinder with a diameter of Φ250 (-0.2 to 0)mm and a height of 10 (-0.2 to -0.3)mm, so as to achieve a tight fit between the cylindrical end of the aluminum guide rod and the stepped structure of the aluminum alloy transition deposition layer.

[0087] Welding of the aluminum guide rod and anode steel claw: A trace amount of surface-metallized carbon nanomaterials, such as nickel-plated carbon nanotubes or graphene, is added to the mating surface of the aluminum guide rod and the aluminum alloy transition deposition layer. The addition amount is preferably less than 0.1 wt.% to prevent agglomeration. After assembly, one side of the aluminum guide rod is fixed, and a rotary friction welding method is used. Under the parameters of a rotation speed of 300 rpm to 1500 rpm, a pressure of 20 MPa to 100 MPa, a friction time of 5 s to 15 s, and a forging pressure of 40 MPa to 160 MPa, the aluminum alloy at the interface undergoes plastic deformation under continuous pressure and relative displacement, achieving interatomic bonding. The forging process is held at pressure for 10 s to allow the joint to complete crystallization and preliminary cooling and shaping under pressure. Then the pressure is released to obtain a fully bonded joint.

[0088] This design uses surface Si enrichment methods such as deformation-driven deposition, friction stir deposition, hot-dip galvanizing, magnetron sputtering, and silanization to form a Si-containing microlayer of a certain thickness on the steel surface. Then, by using a design concept of breaking down the whole into parts and layer by layer, a steel-aluminum transition deposition layer is prepared using deformation-driven deposition to serve as a joint, i.e., a connector or connection position. This improves the metallurgical reaction at the interface, reduces residual stress, and avoids the deterioration of joint performance. Moreover, the material does not undergo a melting-solidification process during the preparation process, which has energy-saving and environmentally friendly technical characteristics. It also fundamentally solves the problem of brittle intermetallic compounds in steel-aluminum transition joints causing joint performance deterioration.

[0089] It should be noted that other embodiments of this application also include solid-state welding methods and aluminum-steel composite connecting components formed by combining the technical features of the above embodiments.

[0090] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the patent protection scope of this application should be determined by the appended claims.

Claims

1. A solid-state welding method, characterized in that, Including the following steps: Using aluminum alloy as raw material, a stepped aluminum alloy transition deposition layer is deposited on the connection position of the anode steel claw using solid-phase additive manufacturing to form an aluminum alloy transition deposition layer covering the surface of the connection position. The stepped structure of the aluminum alloy transition deposition layer is processed to reduce surface roughness; The aluminum guide rods to be connected are processed to form a mating structure that matches the stepped structure; The anode steel claw is assembled with the aluminum guide rod so that the stepped structure and the mating structure fit tightly together, and the anode steel claw and the aluminum guide rod are fixed. Friction welding is performed on the anode steel claw and the aluminum guide rod, causing the aluminum alloy at the interface where the stepped structure and the mating structure are in contact to undergo plastic deformation under continuous pressure and relative displacement, forming a composite interface joint.

2. The solid-state welding method according to claim 1, characterized in that, After the friction welding is completed, the solid phase welding method further includes the steps of: rapidly increasing the axial pressure to achieve upsetting, so that the composite interface joint completes crystallization and preliminary cooling and shaping under pressure, and then the pressure is removed.

3. The solid-state welding method according to claim 1, characterized in that, Prior to the friction welding, the solid-state welding method further includes the step of: premixing surface-metallized carbon nanomaterials into the interface to be bonded at least one of the stepped structure and the mating structure, in order to construct additional conductive pathways.

4. The solid-state welding method according to claim 1, characterized in that, The stepped structure includes annular stepped structures and rectangular stepped structures.

5. The solid-state welding method according to claim 1, characterized in that, The stepped structure is cylindrical or cylindrical.

6. The solid-state welding method according to claim 1, characterized in that, The diameter of the stepped structure is 100mm to 600mm; the wall thickness is 10mm to 50mm; and the height is 10mm to 20mm.

7. The solid-state welding method according to claim 1, characterized in that, The aluminum alloy transition deposition layer, except for the stepped structure, has a preset thickness of 10mm to 20mm; or, the preset thickness is set according to the shape and size of the surface at the location to be connected; or, the protrusion height of both the stepped structure and the mating structure is 20mm to 60mm.

8. The solid-state welding method according to any one of claims 1 to 7, characterized in that, The solid-state additive manufacturing method includes at least one of continuous wire feeding friction stir additive manufacturing, friction stir deposition, solid-state deformation driven deposition, and friction surfacing.

9. The solid-state welding method according to any one of claims 1 to 7, characterized in that, The friction welding includes at least one of rotary friction welding, linear friction welding, and inertial friction welding.

10. An aluminum-steel composite connecting component, characterized in that, It is prepared by the solid-state welding method as described in any one of claims 1 to 9.

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