A method for manufacturing an aluminum electrolytic cell shell

Abstract

The present invention relates to the technical field of electrolytic cell processing, and discloses a method for manufacturing an aluminum electrolytic cell shell, comprising the following steps: S1, steel selection: selecting steel required by the design; S2, shell blanking: cutting the steel into the required structure; S3, shell preparation: assembling the long side assembly, short side assembly, bottom plate assembly and corresponding accessory components through a jig; S4, shell welding: welding and inspecting the assembled shell; S5, shell painting: painting the shell after rust removal. The present invention selects different cutting methods according to steels of different sizes in shell blanking to ensure that the blanking size meets the design requirements; in shell preparation, the shell structure is assembled through different types of jigs to ensure assembly accuracy; in shell welding, different welding processes are adopted according to different welds to ensure that the welds meet the requirements; and after passing the inspection, the shell is painted. The prepared electrolytic cell shell has good quality and a long service life.

Description

Technical Field

[0001] The invention relates to the technical field of electrolytic cell processing, in particular to a method for manufacturing a cell shell of an aluminum electrolytic cell. Background Art

[0002] Electrolytic aluminum is mainly used to produce aluminum processed materials for various purposes. Aluminum is widely used in life, and the most widely used areas are real estate and automobiles. Electrolytic aluminum is aluminum obtained by electrolysis. Modern electrolytic aluminum industry production adopts cryolite-alumina molten salt electrolysis method. Molten cryolite is the solvent, alumina is the solute, carbonite is the anode, and aluminum liquid is the cathode. After a strong direct current is passed through, an electrochemical reaction is carried out at the two poles in the electrolytic cell at 950℃-970℃. Due to being in a high temperature environment for a long time, the electrolytic cell shell will undergo high-temperature deformation and corrosion during the long-term production process. Among them, the deformation of the long side of the electrolytic cell shell is the most serious. Therefore, it needs to be replaced during long-term operation, which requires the preparation of the electrolytic cell shell.

[0003] A Chinese patent discloses a method for manufacturing a pre-baked aluminum electrolytic cell shell (authorization announcement number CN103203589A). This patented technology uses a short side plate structure to make a mold, a long side plate structure to make a mold, and a bottom panel to turn the mold, making the production process of the pre-baked aluminum electrolytic cell shell more convenient and quick. However, the quality of the electrolytic cells produced is not high, resulting in a short actual service life. Summary of the Invention

[0004] The object of the present invention is to provide a method for manufacturing a shell of an aluminum electrolysis cell to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for manufacturing an aluminum electrolysis cell shell comprises the following steps:

[0007] S1. Steel selection: Select steel that meets the design requirements and check the steel's tensile strength, elongation, yield point, cold bending test, and sulfur and phosphorus content limits, and attach the manufacturer's quality certificate. At the same time, check the steel's appearance. Steel with cracks, shrinkage cavities, bubbles, heavy skin, and slag inclusions shall not be put into use.

[0008] S2. Tank shell blanking: Cut and process the steel materials according to the requirements of the design drawings to produce the steel materials required for the tank shell; small-sized steel materials are cut by mechanical cutting, while large-sized steel materials and special-shaped steel materials must be cut by gantry-type plasma CNC cutting to produce the long side components, short side components, bottom plate components and corresponding auxiliary components of the tank shell. Among them, the long side components are composed of long side brackets and long side wall plates, and the short side components are composed of short side brackets and short side wall plates, thus completing the tank shell blanking; S3. Tank shell preparation: Pair the long side brackets on the pairing jig; assemble the paired long side brackets and long side shell plates on the sub-assembly jig to complete the assembly of the long side components of the tank shell. At the same time, the assembly of the short side components, bottom plate components and corresponding auxiliary components can be completed;

[0009] S4. Tank shell welding: move the assembled tank shell long side assembly together with the assembly jig and sub-assembly jig to the welding workbench; use CO2 gas shielded welding for welding; form an integral tank shell long side assembly, and after removing from the assembly jig and sub-assembly jig, check whether the quality and appearance size of the tank shell long side assembly after welding meet the design requirements. If so, mass production will be carried out; similarly, complete the welding and inspection of the short side assembly, bottom plate assembly and corresponding auxiliary components; then assemble the long side assembly, short side assembly, bottom plate assembly and corresponding auxiliary components together through the final assembly jig, weld again, and after passing the inspection, the tank shell welding is completed and then removed from the final assembly jig; when the old electrolytic cell needs to be modified and replaced, cut off the corresponding structure of the old electrolytic cell along the original weld, and after grinding the cut weld smooth, fix the assembled and welded corresponding structure to the position after cutting through the final assembly jig, and weld and inspect;

[0010] S5. Tank shell painting: Derust the surface of the tank shell. After the surface rust removal treatment, apply a layer of anti-rust primer on the outside of the tank shell. After the primer is dry, apply a layer of high-temperature resistant asphalt topcoat to complete the production of the electrolytic cell shell.

[0011] As a further solution of the present invention: if other steel materials need to be used to replace the steel materials selected in the design in the step S1, the mechanical properties and mechanical properties of the steel materials shall not be lower than the corresponding properties of the steel materials selected in the design, and the mechanical properties and mechanical properties shall be verified.

[0012] As a further solution of the present invention: in the step S1, the flash, burrs and slag on the edges of the steel must be removed after cutting; and for the butt welds and fillet welds connecting the plates not indicated in the design drawings, the connecting surfaces of the non-free edges must be machined, and the machining accuracy Ra value must be not less than 25.

[0013] As a further solution of the present invention: in the step S4, before welding, all welds need to be cleaned with an angle grinder to ensure the welding quality, and for steel materials welded in butt welding, when the thickness of the steel material is 3<δ≤9, the root gap b=1±1, the blunt edge P=1±1, the groove angle α=70°±5°, and when δ>9, the root gap blunt edge Groove angle α=70°±5°; for steel using I-shaped welding, the actual height of the steel after welding h=design dimension h0±1.0; for steel using T-shaped welding, the vertical deviation of the steel Δ<1.0; for steel using H-shaped welding, half of the actual width of the steel after welding Δ=1 / 2 design width A±1.0; for steel using lap welding, the lap length B>5.0 and the lap gap δ<1.5.

[0014] As a further solution of the present invention: in the step S4, the welding workbench adopts a multi-station workbench, and the temperature rise is controlled by multi-station rotation welding to prevent the welded parts from heating up and deforming significantly; and the welding environment temperature must not be lower than 5°C, otherwise corresponding measures must be taken to ensure the welding quality.

[0015] As a further solution of the present invention: in the S4 step, the quality inspection after welding needs to be checked by hammering one by one, and the weld should be full, completely penetrated, smooth in surface, and the weld edge should have a smooth connection with the parent steel; the weld should not have defects such as cracks, undercuts, bubbles, slag inclusions, discontinuities, etc.; and for important welds marked in the design drawings, 100% ultrasonic testing and 100% magnetic particle testing are required; important welds include the vertical welds between the long side wall panels and the short side wall panels, and the welds between the long side wall panels and the bottom plate assembly.

[0016] As a further solution of the present invention: in the step S5, oil stains, paint stains, rust and scale rust on the surface of the tank shell are removed by rust removal; the temperature resistance of the high-temperature resistant asphalt topcoat is ≥300°C, and during the coating process, the ambient temperature shall not be lower than 5°C and the relative humidity shall not be higher than 80%.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention prepares an electrolytic cell shell through steel selection, shell cutting, shell preparation, shell welding, and shell painting. Different cutting methods are selected according to steels of different sizes in shell cutting to ensure that the cutting size meets the design requirements. In shell preparation, the shell structure is assembled by different types of jigs to ensure assembly accuracy. In shell welding, different welding processes are adopted according to different welds to ensure that the welds meet the requirements. After passing the inspection, the shell is painted. The prepared electrolytic cell shell has good quality and a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of a tank shell in a method for manufacturing a tank shell of an aluminum electrolytic cell;

[0020] Figure 2 This is a schematic diagram of the exploded structure of a tank shell in a method for manufacturing a tank shell of an aluminum electrolytic cell;

[0021] Figure 3 This is a schematic diagram of the structure of the long side components in a method for manufacturing a tank shell of an aluminum electrolytic cell;

[0022] Figure 4 This is a schematic structural diagram of a short side component in a method for manufacturing a tank shell of an aluminum electrolysis cell;

[0023] Figure 5 This is an acceptance checklist for the overall installation of a method for manufacturing an aluminum electrolytic cell shell;

[0024] Figure 6 This is an acceptance checklist for partial replacement in a method for manufacturing an aluminum electrolytic cell shell;

[0025] Figure 7 A schematic diagram of the structure of butt welding in a method for manufacturing a tank shell of an aluminum electrolytic cell;

[0026] Figure 8 A schematic diagram of the structure of I-shaped welding in a method for manufacturing a tank shell of an aluminum electrolytic cell;

[0027] Figure 9 A schematic diagram of the structure of T-shaped welding in a method for manufacturing a tank shell of an aluminum electrolytic cell;

[0028] Figure 10 A schematic diagram of the H-shaped welding structure in a method for manufacturing an aluminum electrolytic cell shell;

[0029] Figure 11 The present invention is a structural schematic diagram of overlap welding in a method for manufacturing an aluminum electrolytic cell shell.

[0030] In the figure: 1. Long side assembly; 2. Short side assembly; 3. Bottom plate assembly; 4. Accessory components; 11. Long side wall plate; 12. Long side corbel; 41. Short side wall; 42. Short side corbel. DETAILED DESCRIPTION

[0031] See also Figures 1 to 11 In an embodiment of the present invention, a method for manufacturing a shell of an aluminum electrolysis cell includes the following steps:

[0032] S1. Steel selection: Select steel that meets the design requirements, such as Q345B steel, and check the steel's tensile strength, elongation, yield point, cold bending test, and sulfur and phosphorus content limits, and attach the manufacturer's quality certificate. At the same time, inspect the steel's appearance. Steel with cracks, shrinkage cavities, bubbles, heavy skin, and slag inclusions shall not be put into use. For dimensional tolerances not specified in the design drawings, GB / T 1804-2000 (General tolerances - Tolerances for linear and angular dimensions without tolerances) in GB / T 1804-m grade shall apply, see Tables 1 and 2 below.

[0033] Table 1 Limit deviation values of linear dimensions

[0034]

[0035]

[0036] Table 2 Limit deviation values of chamfer radius and chamfer height

[0037]

[0038] S2. Cutting of the trough shell: Cut the steel according to the design drawings to produce the steel required for the trough shell. Small-sized steel is cut by mechanical shearing, while large-sized steel and special-shaped steel must be cut by gantry-type plasma CNC cutting. The long side assembly 1, short side assembly 2, bottom plate assembly 3 and corresponding auxiliary components 4 of the trough shell are processed. The long side assembly consists of the long side bracket 12 and the long side wall plate 11, and the short side assembly consists of the short side bracket 42 and the short side wall plate 41. The trough shell is cut to ensure that the cut steel meets the requirements of the drawings to reduce deformation caused by traditional flame cutting.

[0039] S3. Tank shell preparation: assemble the long side corbels 12 on an assembly jig; assemble the assembled long side corbels 12 and the long side shell plates 11 on an assembly jig to complete the assembly of the tank shell long side assembly 1. Simultaneously, the assembly of the short side assembly 2, the bottom plate assembly 3, and the corresponding accessory components 4 can be completed.

[0040] S4. Tank shell welding: move the assembled tank shell long side 1 component together with the pairing jig and the sub-packaging jig to the welding workbench; use CO2 gas shielded welding for welding; form an integral tank shell long side component 1, and after separating from the pairing jig and the sub-packaging jig, check whether the quality and appearance size of the tank shell long side component 1 after welding meet the design requirements. If so, mass-produce it. Due to the large number of long side tank shell structures and the large amount of steel required, the tank shell structure should be trial-produced as one, and then mass-produced after passing the acceptance test, so as to avoid major losses; similarly, complete the welding and inspection of the short side component 2, the bottom plate component 3 and the corresponding auxiliary components 4; then assemble the long side component 1, the short side component 2, the bottom plate component 3 and the corresponding auxiliary components 4 together through the final assembly jig, and weld them again. After passing the inspection, the form used for the inspection is shown in Figure 5 , the tank shell is welded and then separated from the assembly jig; when the old electrolytic cell needs to be modified and replaced, the corresponding structure of the old electrolytic cell is cut along the original weld, and the weld after cutting is polished and smoothed, and the corresponding structure after welding is fixed in the position after cutting through the assembly jig, and welding and inspection are carried out. The inspection form is shown in Figure 6 Due to the production process, the long side tank shell is often the most seriously damaged, so it is also the long side tank shell that needs to be replaced;

[0041] S5. Tank shell painting: Derust the surface of the tank shell. After the surface rust removal treatment, apply a layer of anti-rust primer on the outside of the tank shell. After the primer is dry, apply a layer of high-temperature resistant asphalt topcoat to complete the production of the electrolytic cell shell.

[0042] Preferably, in step S1, if other steel materials need to be used to replace the steel materials selected in the design, the mechanical properties and mechanical properties of the steel materials shall not be lower than the corresponding properties of the steel materials selected in the design, and the mechanical properties and mechanical properties shall be verified.

[0043] Preferably, in step S1, the flash, burrs and slag on the edges of the steel must be removed after cutting; and for butt welds and fillet welds connecting plates not indicated in the design drawings, their non-free edge connection surfaces must be machined, and the machining accuracy Ra value must be not less than 25.

[0044] Preferably, in step S4, before welding, all welds need to be cleaned with an angle grinder to ensure welding quality, and the steel materials welded in butt welding, such as Figure 7 As shown, when the thickness of the steel is 3<δ≤9, the root gap b=1±1, the blunt edge P=1±1, the groove angle α=70°±5°, when δ>9, the root gap blunt edge Groove angle α=70°±5°; Use I-shaped welded steel, such as Figure 8As shown in the figure, the actual height of the steel after welding h = design dimension h0±1.0; for steel using T-shaped welding, such as Figure 9 As shown, the vertical deviation of steel is Δ<1.0; steel with H-shaped welding, such as Figure 10 As shown, half of the actual width of the steel after welding Δ=1 / 2 design width A±1.0; steel welded in lap form, such as Figure 11 As shown, the lap length of steel B>5.0, the lap gap δ

[0045] <1.5.

[0046] Preferably, in step S4, the welding workbench adopts a multi-station workbench, and the temperature rise is controlled by rotating welding at multiple stations to prevent the welded parts from heating up and deforming greatly; and the welding environment temperature must not be lower than 5°C, otherwise corresponding measures must be taken to ensure the welding quality. During the welding process, there are hidden welds, which must be inspected and qualified before entering the next welding process.

[0047] Preferably, in step S4, the quality inspection after welding needs to be checked by hammering one by one, and the weld should be full, completely penetrated, smooth in surface, and the weld edge should have a smooth connection to the parent steel; the weld should not have defects such as cracks, undercuts, bubbles, slag inclusions, discontinuities, etc.; if any defects occur, they must be scraped off and re-welded, and must not be covered up; the flux slag must be cleaned up; and for important welds marked in the design drawings, 100% ultrasonic testing and 100% magnetic particle testing are required; important welds include the vertical welds between the long side wall plate and the short side wall plate, and the welds between the long side wall plate and the bottom plate assembly.

[0048] Weld assessment standards: inspect, assess and accept weld quality according to the grade specified in the table (or standard).

[0049] a. Ultrasonic inspection shall refer to the Grade I weld quality using Grade A inspection as specified in "Ultrasonic Testing Technology, Testing Grades and Assessment for Non-destructive Testing of Welds" (GB / T11345-2013).

[0050] b. The appearance inspection of steel fusion welds shall refer to the "Welding Quality Assurance Requirements and Defect Classification of Steel Fusion Welded Joints"

[0051] (GB / T12469-90) specified in the Grade II weld quality.

[0052] Table 3 Weld quality classification

[0053]

[0054]

[0055] In Table 3 above: 1) When the undercut is ground and trimmed to achieve a smooth transition, it can be assessed according to the minimum allowable thickness of the thinner base material on one side of the weld;

[0056] 2) When a smooth transition is required under specific conditions, it is not subject to the restrictions of this regulation (such as lap joints or butt and fillet joints of unequal thickness plates);

[0057] 3) Except for the fillet weld defects noted, the rest are common to butt welds and fillet welds;

[0058] 4) In the table, a is the effective thickness of the designed weld; δ is the thickness of the parent material;

[0059] c. Radiographic inspection shall refer to the Grade II weld quality specified in "Radiography of Metal Fusion Welding Joints" (extracted from GB / T3323-2005);

[0060] Table 4 Defect grade classification

[0061]

[0062]

[0063] Preferably, in step S5, oil stains, paint stains, rust and scale rust on the surface of the tank shell are removed by rust removal, and the rust removal standard complies with the provisions of GB / T 8923-2011 (Surface treatment of steel before coating - Visual assessment of surface cleanliness); the temperature resistance of the high-temperature resistant asphalt topcoat is ≥300°C, and during the coating process, the ambient temperature shall not be lower than 5°C and the relative humidity shall not be higher than 80%. The coating standard complies with the provisions of GB50046-2008 (Design Code for Anti-corrosion of Industrial Buildings) and JB / T 5000.12-2007 (General Technical Conditions for Heavy Machinery Part 12: Coating).

[0064] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for manufacturing an aluminum electrolysis cell shell, characterized in that: The following steps are involved: S1. Steel selection: Select steel that meets the design requirements and check the steel's tensile strength, elongation, yield point, cold bending test, and sulfur and phosphorus content limits, and attach the manufacturer's quality certificate. At the same time, check the steel's appearance. Steel with cracks, shrinkage cavities, bubbles, heavy skin, and slag inclusions shall not be put into use. S2. Cutting of the tank shell: Cutting and processing the steel materials according to the requirements of the design drawings to produce the steel materials required for the tank shell; the cutting of small-sized steel materials adopts mechanical cutting, and the cutting of large-sized steel materials and special-shaped steel materials must adopt gantry-type plasma CNC cutting to process the long side components (1), short side components (2), bottom plate components (3) and corresponding auxiliary components (4) of the tank shell, wherein the long side components are composed of long side brackets (12) and long side wall plates (11), and the short side components are composed of short side brackets (42) and short side wall plates (41), thus completing the cutting of the tank shell; S3, tank shell preparation: assembling the long side brackets (12) on the assembly jig; assembling the assembled long side brackets (12) and the long side wall plates (11) together on the assembly jig to complete the assembly of the tank shell long side assembly (1), and at the same time, completing the assembly of the short side assembly (2), the bottom plate assembly (3) and the corresponding auxiliary components (4); S4, tank shell welding: the assembled tank shell long side assembly (1) is moved together with the assembly jig and the sub-assembly jig to the welding workbench; CO2 gas shielded welding is used for welding; a whole tank shell long side assembly (1) is formed, and after being separated from the assembly jig and the sub-assembly jig, the quality and appearance size of the tank shell long side assembly (1) after welding are checked to see if they meet the design requirements. If so, large-scale cutting and production are carried out; similarly, the short side assembly (2), the bottom plate assembly (3) and the corresponding auxiliary components (4) are welded and inspected; the long side assembly (1), the short side assembly (2), the bottom plate assembly (3) and the corresponding auxiliary components (4) are assembled together by the assembly jig, and welded again. After passing the inspection, the tank shell welding is completed and the assembly jig is separated; when the old electrolytic cell needs to be modified and replaced, the corresponding structure of the old electrolytic cell is cut along the original weld seam, and the cut weld seam is polished and smoothed. The assembled and welded corresponding structure is fixed to the position after cutting by the assembly jig, and welding and inspection are carried out; S5. Tank shell painting: Derust the surface of the tank shell. After the surface rust removal treatment, apply a layer of anti-rust primer on the outside of the tank shell. After the primer is dry, apply a layer of high-temperature resistant asphalt topcoat to complete the production of the electrolytic cell shell.

2. The method for manufacturing an aluminum electrolysis cell shell according to claim 1, characterized in that: In the step S1, if other steel materials need to be used to replace the steel materials selected in the design, the mechanical properties and mechanical properties of the steel materials shall not be lower than the corresponding properties of the steel materials selected in the design, and the mechanical properties and mechanical properties shall be verified.

3. The method for manufacturing an aluminum electrolysis cell shell according to claim 1, wherein: In the S1 step, the flash, burrs and slag on the edges of the steel must be removed after cutting; and for butt welds and fillet welds connecting plates not indicated in the design drawings, the non-free edge connection surfaces must be machined, and the machining accuracy Ra value must be not less than 25.

4. The method for manufacturing an aluminum electrolysis cell shell according to claim 1, characterized in that: In the step S4, before welding, all welds need to be cleaned with an angle grinder to ensure welding quality. For butt welding of steel, when the thickness of the steel is 3<δ≤9, the root gap b=1±1, the blunt edge P=1±1, the groove angle α=70°±5°, and when δ>9, the root gap b= , blunt edge P = , groove angle α=70°±5°; for steel using I-shaped welding, the actual height of the steel after welding h=design dimension h0±1.0; for steel using T-shaped welding, the vertical deviation of the steel Δ<1.0; for steel using H-shaped welding, half of the actual width of the steel after welding Δ=1 / 2 design width A±1.0; for steel using lap welding, the lap length of the steel B>5.0, and the lap gap δ<1.

5.

5. The method for manufacturing an aluminum electrolysis cell shell according to claim 1, characterized in that: In the step S4, the welding workbench adopts a multi-station workbench, and the temperature rise is controlled by rotating welding at multiple stations to prevent the welded parts from heating up and deforming greatly; and the welding environment temperature must not be lower than 5°C, otherwise corresponding measures must be taken to ensure the welding quality.

6. The method for manufacturing an aluminum electrolysis cell shell according to claim 1, characterized in that: In the S4 step, the quality inspection after welding needs to be checked by hammering one by one, and the weld should be full, completely penetrated, smooth in surface, and smoothly connected to the parent steel. The weld should not have cracks, undercuts, bubbles, slag inclusions, or discontinuities. In addition, for important welds marked in the design drawings, 100% ultrasonic testing and 100% magnetic particle testing are required. Important welds include the vertical welds between the long side wall panels and the short side wall panels, and the welds between the long side wall panels and the bottom plate assembly.

7. The method for manufacturing an aluminum electrolysis cell shell according to claim 1, characterized in that: In the step S5, oil stains, paint stains, rust and scale rust on the surface of the tank shell are removed by rust removal; the temperature resistance of the high-temperature resistant asphalt topcoat is ≥300°C, and during the coating process, the ambient temperature shall not be lower than 5°C and the relative humidity shall not be higher than 80%.

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