Steel-aluminum composite anode claw for electrolytic aluminum

Abstract

The utility model discloses a steel-aluminum composite anode claw for electrolytic aluminum, which comprises an outer steel layer and an inner aluminum core, the aluminum core is exposed at a conductive end, and the outer steel layer and the inner aluminum core are metallurgically bonded together without a gap; the outer steel layer comprises a connecting pipe, a cross beam pipe and a clamping pipe. And the outer steel layer is an integral hollow steel casting, or is formed by welding two steel castings with semicircular symmetrical structures, or is formed by welding a connecting pipe, a cross beam pipe and a clamping pipe. Annular protrusions or annular grooves are arranged on the inner surfaces of the connecting pipe and the clamping pipe, or the annular protrusions and the grooves are combined, and the protrusions or the grooves are in a spiral shape or in a single ring shape. According to the utility model, steel and aluminum are integrated through metallurgical compounding, and the conductivity and the mechanical property of the anode claw are respectively borne by the aluminum core and the outer steel layer, so that the size of the anode claw is reduced, and the overall weight of the anode claw is reduced.

Description

Technical Field

[0001] The utility model is applied to the field of aluminum electrolysis and relates to an anode steel claw of an aluminum electrolytic cell, in particular to a steel-aluminum composite anode claw. Background Art

[0002] The anode claw of electrolytic aluminum is an important connecting component between the guide rod and the carbon block in the electrolytic cell. It is a structural and functional integrated material that requires good electrical conductivity and mechanical properties. The anode claw needs to withstand the strong current passed into the electrolytic cell during the aluminum electrolysis production process. The average current passing through each steel claw is about 15,000A, so the anode claw is required to have good electrical conductivity; in addition, the anode claw plays the role of connecting the aluminum guide rod and clamping the anode carbon block. Since each anode weighs 700 to 1,000 kg, the anode claw is required to have a certain strength and dimensional stability.

[0003] Aluminum and copper have excellent electrical conductivity, but their mechanical properties are not as good as steel. Electrical conductivity mainly affects the production cost of electrolytic aluminum, while mechanical properties directly affect the normal production of electrolytic aluminum, so most anode claws now use steel claws. In terms of improving the conductivity of anode steel claws, some patent applications start from the production process or the composition of steel, such as the production process of a low-resistivity and high-performance anode steel claw disclosed in CN117340548A, which is made of BTCY-1 hot-rolled steel; the friction welding process is adopted, the welding fusion rate is greater than or equal to 99%, and the resistivity is less than 11μΩ·mm at 20°C; CN117626137A discloses a low-resistivity energy-saving double anode steel claw and its preparation method, which uses iron-carbon alloy as raw material and is reinforced with 235B steel plate, and the impurity components of the iron-carbon alloy are controlled within the following ranges: C≤0.005%, Mn≤0.10%, Si≤0.01%, 0.003%≤P≤0.005%, S≤0.007%. The utility model patent "A Method for Producing Anode Steel Claws" (2024105474652) applied by the previous applicant takes process measures from multiple aspects such as alloy elements, impurities, casting defects, organization, and grain size to improve the conductivity of cast anode steel claws. Some patent applications use steel-aluminum composite materials to reduce resistivity. For example, CN116926629A discloses an anode conductive device and a steel-aluminum connection method, a steel-aluminum connection structure, and a steel-aluminum composite sheet. The steel sheet of the steel-aluminum composite sheet includes a steel transverse joint and a steel claw joint, and the aluminum sheet includes an aluminum transverse joint and an aluminum guide rod joint. The transverse joints of steel and aluminum are tightly compounded to form a "steel-aluminum transverse joint structure" and a weld meat accommodating notch is formed. When the steel-aluminum composite sheet is used, the weld meat accommodating notch can ensure that each composite sheet can be stacked and arranged closely, which not only has a high connection strength, but also greatly reduces the resistance and contact voltage drop. CN203999844U discloses a steel-aluminum composite anode steel claw, comprising a grooved steel frame, a steel pipe above the grooved steel frame, and a round steel claw below the grooved steel frame. The round steel claw is provided with a casting hole connected to the grooved steel frame; the steel pipe, the grooved steel frame, and the casting hole of the round steel claw are all cast with an aluminum core to form a composite structure of steel-clad aluminum. The transverse round steel and reinforcing steel in the grooved steel frame of the composite steel claw will restrict the shrinkage of cast aluminum and easily produce shrinkage cracks. Moreover, a large current still needs to pass through the round steel claw, and the cast aluminum shrinks and cannot form a metallurgical bond with steel, so the effect of reducing power consumption is not obvious. Utility Model Content

[0004] The technical problem solved by the utility model is to provide a steel-aluminum composite anode claw for electrolytic aluminum, wherein an outer steel layer is metallurgically combined with an aluminum core, the outer steel layer is used to ensure the mechanical properties of the anode claw, and the aluminum core is used to achieve good electrical conductivity of the anode claw.

[0005] The technical solution adopted by the utility model is: the steel-aluminum composite anode claw for electrolytic aluminum includes an outer steel layer and an aluminum core, wherein the aluminum core is located in the outer steel layer and leaks out at the conductive end of the anode claw. There is no gap between the outer steel layer and the aluminum core, and they are metallurgically combined together. The outer steel layer structurally includes a connecting tube, a crossbeam tube and a clamping tube. The connecting tube is above the crossbeam tube and is used to connect the guide rod, and the clamping tube is below the crossbeam tube and is used to connect the carbon block.

[0006] Preferably, the outer steel layer is an integral hollow steel casting, which is conducive to designing the composition of the cast steel according to the working conditions of the anode claw.

[0007] Preferably, the outer steel layer is formed by welding two steel castings with semicircular symmetrical structures, which is conducive to casting and cleaning of the inner surface.

[0008] Preferably, the outer steel layer is welded by a connecting tube, a crossbeam tube and a clamping tube. The crossbeam tube is a hot-rolled tube, and the connecting tube and the clamping tube can be a hot-rolled tube or a cast steel tube.

[0009] Preferably, the inner surfaces of the connecting tube and the clamping tube are provided with an annular protrusion, an annular groove, or a combination of an annular protrusion and a groove. This structure is conducive to increasing the steel-aluminum bonding area and improving the metallurgical composite quality. The protrusion or groove can be a continuous spiral or a discontinuous single ring.

[0010] Preferably, since copper has better electrical conductivity than aluminum, the aluminum core is replaced by a copper core.

[0011] The beneficial effects of the utility model are as follows: the metallurgical composite of the utility model integrates steel and aluminum, and utilizes the excellent properties of both, so that the conductive property and mechanical property of the anode claw are respectively borne by the aluminum core and the outer steel layer, which not only reduces the size of the anode claw, but also reduces the overall weight of the anode claw. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the steel-aluminum composite anode claw structure of Example 1;

[0013] Figure 2 This is a schematic diagram of the steel-aluminum composite anode claw structure of Example 2;

[0014] Figure 3 This is a schematic diagram of the steel-aluminum composite anode claw structure of Example 3;

[0015] Figure 4 This is a schematic diagram of the steel-aluminum composite anode claw structure of Example 4;

[0016] Figure 5 for Figure 4 A right side schematic diagram of

[0017] In the figure: 1-outer steel layer, 2-aluminum core, 3-connecting tube, 4-crossbeam tube, 5-clamping tube, 6-groove, 7-protrusion, 8-weld. DETAILED DESCRIPTION

[0018] The utility model takes a three-claw anode claw as an example to describe the structure, but is not limited to the three-claw structure. The metallurgical bonding described in the utility model refers to bonding together by atomic diffusion. Example 1

[0019] The anode claw of this embodiment is as shown in the attached Figure 1 As shown, it comprises an outer steel layer 1 and an aluminum core 2, wherein the aluminum core 2 is located inside the outer steel layer 1 and leaks out at the conductive end of the anode claw. There is no gap between the aluminum core 2 and the outer steel layer 1, and they are metallurgically combined together.

[0020] During production, the outer steel layer 1 is poured first, the box is turned over to remove the pouring head, and the inner and outer surfaces are shot blasted. The outer steel layer 1 is used as the cavity for casting aluminum. After the modeling is completed, the aluminum liquid is poured, and the outer steel layer 1 is heated to a temperature close to the melting point of the aluminum liquid. At the same time, pressure is applied to the aluminum liquid. Under pressure and high temperature, the aluminum liquid achieves metallurgical bonding through atomic diffusion. In the subsequent cooling process, the outer steel layer 1 and the aluminum core 2 cool and shrink at the same time, and the aluminum core 2 will not produce shrinkage cracks.

[0021] The outer steel layer has excellent mechanical properties and the aluminum core has excellent electrical conductivity. This embodiment combines the excellent properties of the two materials, using the outer steel layer for mechanical connection and the aluminum core for electrical conductivity. The electrical conductivity and mechanical properties of the anode claw are borne by the aluminum core and the outer steel layer respectively. This structure not only reduces the size of the anode claw, but also reduces the weight of the anode claw. While ensuring continuous production, it reduces power consumption. Example 2

[0022] The outer steel layer 1 in Example 1 has two disadvantages: First, the outer steel layer 1 is hollow and needs to be cored during molding. For large-sized hollow steel castings, it is difficult to prevent the floating core from causing uneven wall thickness. Second, the shot blasting cleaning of the inner surface takes a long time and is not easy to inspect, especially the inner surface of the beam. If the inner surface is not cleaned properly, it will directly affect the diffusion of aluminum atoms and the metallurgical composite quality of the aluminum core.

[0023] In order to solve the above problems, the outer steel layer 1 is changed into a welding form of the connecting pipe 3, the cross beam pipe 4 and the clamping pipe 5, as shown in the attached figure. Figure 2 As shown. The connecting tube 3 is welded to the upper surface of the crossbeam tube 4 for connecting the guide rod, and the clamping tube 5 is welded to the lower surface of the crossbeam tube 4 for connecting the carbon block. The connecting tube 3, the crossbeam tube 4 and the clamping tube 5 are all made of hot-rolled steel pipes, and the outer steel layer is not cast but welded. The inner and outer surfaces of the connecting tube 3, the crossbeam tube 4 and the clamping tube 5 are first shot blasted and then welded into shape. Subsequently, as a mold cavity for cast aluminum, aluminum liquid is poured, and metallurgical bonding is achieved through atomic diffusion under pressure and high temperature. Example 3

[0024] This embodiment is an improvement on the basis of embodiment 2. Figure 3 As shown, an annular protrusion 7 (shown by the left claw), or an annular groove 6 (shown by the middle claw), or an annular protrusion 7 combined with the groove 6 (shown by the right claw) is provided on the inner surface of the connecting tube 3 and the clamping tube 5. This increases the steel-aluminum bonding surface and the bonding force of the two. At the same time, the shrinkage-impeded structure is adopted to make the shrinkage resistance uniform, reduce the shear force of the metallurgical bonding surface, and improve the metallurgical bonding quality. The annular protrusion 7 or the groove 6 can be a spiral connected together, or a single ring that is not connected to each other.

[0025] Since it is difficult to process the annular protrusion 7 or the annular groove 6 on the inner surface of the hot-rolled tube, the connecting tube 3 and the clamping tube 5 of this embodiment can be made of cast steel. The steel-cast connecting tube 3 and the clamping tube 5 and the hot-rolled cross beam tube 4 are welded and formed after the inner and outer surfaces are shot blasted, and used as a cavity for casting aluminum. Aluminum liquid is poured under pressure and high temperature, and metallurgical bonding of the two is achieved through atomic diffusion. Example 4

[0026] Embodiment 3 has two disadvantages: first, the casting size of the cast pipe is smaller than that of embodiment 1, and the floating core is easy to control, but there is still a risk of floating core; second, the composition selection of the cast pipe needs to consider not only the weldability, but also the welding performance of the different materials from the hot-rolled cross beam pipe. For this reason, the outer steel layer of this embodiment is welded in two halves, as shown in the attached figure. Figure 4 and attached Figure 5 As shown, the weld seam 8 is located at the center line of the anode claw in a side view.

[0027] The two halves of the outer steel layer are semicircular symmetrical structures, and a set of molds can be used. Since there is no hollow, there is no need to core the casting, and there will be no floating core phenomenon. The composition of the outer steel layer is selected only considering the welding performance of the material itself, without considering the welding performance with hot-rolled steel. The inner surface of the outer steel layer is open, shot blasting is fast, the cleaning quality is visible, and local supplementary grinding is easy. After the two halves are welded and formed, they serve as the cavity of cast aluminum. Aluminum liquid is poured under pressure and high temperature, and the metallurgical bonding of the two is achieved through atomic diffusion.

[0028] The biggest benefit of Example 1 is that the composition of the cast steel can be reasonably designed according to the working conditions of the anode claw, and the medium frequency furnace smelting can be adjusted at any time without considering its welding performance. For example, if medium carbon or high carbon alloy steel is used, the thickness and weight can be reduced by selecting high-performance cast steel. The biggest benefit of Example 2 is that the hot-rolled tube is purchased from outside and can be sawed according to size. There is no need for the complicated process of casting a hollow outer steel layer. However, the composition of the outer steel layer can only be selected according to the market of the hot-rolled tube, and cannot be designed according to the working conditions of the anode claw. Under normal circumstances, hot-rolled tubes with good welding performance belong to low-carbon steel, and their mechanical properties are relatively low. It is necessary to increase the thickness and weight to ensure that they meet the working conditions of the anode claw. Anode claws with larger size and weight can choose the structure of Example 1, and anode claws with smaller size and weight can choose the structure of Example 2.

[0029] Embodiments 3 and 4 improve the bonding quality between steel and aluminum by increasing the bonding area between the two. Embodiment 4 is suitable for anode claws with relatively simple structure that are symmetrical along the center line and welded in two halves, while embodiment 3 is suitable for anode claws with relatively complex structure, such as a cross-shaped anode claw.

[0030] The utility model makes the conductive performance and mechanical performance of the anode claw borne by the aluminum core and the outer steel layer respectively. By utilizing their respective excellent performances, not only can the conductive cross-sectional size be reduced, but also the overall weight of the anode claw can be reduced, which can ensure continuous production and reduce power consumption. The steel-aluminum composite structure makes the two an integrated structure, and the aluminum core is supported by the outer steel layer. Pressure casting ensures the shrinkage of aluminum liquid and the intrinsic quality and conductive ability of the aluminum core.

[0031] It should be noted that the aluminum core in the utility model can be replaced by a copper core with better conductivity, but the specific gravity of copper is high, which is not conducive to reducing the weight of the anode claw. Another reason is that the melting point of copper is higher than that of aluminum. When casting molten copper, the heating temperature of the outer steel layer is high, which puts forward higher requirements on the pressure resistance and high temperature resistance of the casting mold.

Claims

1. A steel-aluminum composite anode claw for aluminum electrolysis, characterized in that: The invention comprises an outer steel layer and an aluminum core; the aluminum core is located inside the outer steel layer and leaks out at the conductive end; there is no gap between the outer steel layer and the aluminum core, and the outer steel layer and the aluminum core are metallurgically bonded together; the outer steel layer comprises a connecting tube (3), a crossbeam tube (4) and a clamping tube (5), wherein the connecting tube (3) is above the crossbeam tube (4) and the clamping tube (5) is below the crossbeam tube (4); the outer steel layer is an integral steel casting; the outer steel layer is welded by the connecting tube (3), the crossbeam tube (4) and the clamping tube (5); the outer steel layer is welded by two steel castings with a semicircular symmetrical structure; the inner surfaces of the connecting tube (3) and the clamping tube (5) are provided with an annular protrusion (7) or an annular groove (6) or an annular protrusion (7) combined with an annular groove (6); the annular protrusion (7) or the annular groove (6) is spiral or single-ringed.

2. The steel-aluminum composite anode claw for aluminum electrolysis according to claim 1, characterized in that: The aluminum core is replaced by a copper core.

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