A tank bottom assembly, a tank, and a method for forming the tank bottom assembly.

Abstract

This invention relates to the field of tank processing technology, and discloses a tank bottom assembly, a tank, and a method for forming the tank bottom assembly. The tank bottom assembly includes a tank bottom and a transition ring. The transition ring is located at the open end of the tank bottom and is integrally formed with the tank bottom. The outer wall of the transition ring has a first step surface and a second step surface that are vertically arranged. The first step surface is arranged radially along the transition ring, and the outer edge of the second step surface away from the first step surface is inclined towards the outer wall of the tank bottom to form a guide slope. The tank includes a cylindrical section and the aforementioned tank bottom assembly. The method for forming the tank bottom assembly includes the following steps: fixing the outer ring of a constraint plate, and shearing and spinning the plate using a spinning wheel to obtain a first formed part; releasing the outer ring constraint and fixing the inner ring constraint, and flanging and spinning the outer ring using a spinning wheel to form a column section; machining a mating interface on the outer wall of the column section to obtain an integrally formed tank bottom and transition ring. The tank has better quality and lower processing costs.

Description

Technical Field

[0001] This invention relates to the field of tank processing technology, and in particular to a tank bottom assembly, a tank, and a method for forming the tank bottom assembly. Background Technology

[0002] The tank bottom assembly is a critical component of the rocket propellant tank, typically assembled from a tank bottom, a transition ring, and a short shell through welding. The tank bottom connects to the cylindrical shell section via the transition ring, and the structural strength of the tank bottom and the connection strength between the bottom and the transition ring determine the load-bearing capacity of the rocket propellant tank. The tank bottom and transition ring are often welded together from multiple segments, resulting in numerous weld seams throughout the assembly, significantly impacting its structural efficiency and stability. Furthermore, while existing technologies incorporate stepped surfaces on the transition ring for connection with the short shell, the short shell and transition ring use an interference fit. When the tank bottom has a large ellipticity, the butt joint between the short shell and transition ring becomes difficult, and insufficient control over dimensional and positional tolerances can easily lead to misalignment during subsequent welding, affecting quality.

[0003] Therefore, there is an urgent need for a tank bottom assembly, a tank, and a method for forming the tank bottom assembly to solve the above problems. Summary of the Invention

[0004] Based on the above, the purpose of this invention is to provide a tank bottom assembly, a tank, and a method for forming the tank bottom assembly, which has relatively reliable structural strength, is easy to assemble, and has high docking accuracy; the tank has better quality; the processing cost is lower and the efficiency is higher.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A tank bottom assembly, comprising:

[0007] Bottom of the box;

[0008] A transition ring is disposed at the open end of the bottom of the box and is integrally formed with the bottom of the box. The outer wall of the transition ring has a first step surface and a second step surface that are vertically arranged. The first step surface is arranged radially along the transition ring, and the second step surface is inclined toward the outer wall of the bottom of the box away from the outer edge of the first step surface to form a guide slope.

[0009] As a preferred embodiment of the tank bottom assembly, it also includes:

[0010] A short shell is fitted over the bottom of the box, and the interface end of the short shell abuts against the first step surface and the second step surface.

[0011] As a preferred embodiment of the tank bottom assembly, the outer perimeter of the transition ring is a, the inner perimeter of the short shell is b, and the width of the guide ramp in the radial direction of the transition ring is c, where c is in the range of (ab) / 6 to (ab) / 5.

[0012] A storage tank includes a cylindrical section and a storage tank bottom assembly as described in any of the above technical solutions, wherein the cylindrical section is connected to one end of the transition ring opposite to the tank bottom.

[0013] A method for forming a tank bottom assembly includes the following steps:

[0014] Prepare the boards;

[0015] The outer ring of the sheet metal is fixed and constrained, and the sheet metal is sheared and spun to the contour of the target box bottom by a spinning wheel to obtain the first formed part;

[0016] Release the outer ring constraint of the first forming part and fix the inner ring constraint of the first forming part. Then, use the spinning wheel to flanging and spinning the outer ring of the first forming part to form a column segment.

[0017] A mating interface is machined on the outer wall of the column section to obtain an integrally formed box bottom and transition ring.

[0018] As a preferred embodiment of a tank bottom assembly forming method, after the column segment is formed on the outer ring of the first forming part, the tank bottom portion is processed to make the thickness of the tank bottom reach a preset thickness.

[0019] As a preferred embodiment of the tank bottom assembly forming method, when processing the docking interface, a first step surface radially arranged along the transition ring and a second step surface perpendicular to the first step surface are processed on the outer wall of the column segment, and a guide slope is processed at the end of the second step surface away from the first step surface toward the tank bottom.

[0020] A preferred embodiment of a method for forming a tank bottom assembly further includes the following steps:

[0021] Prepare short shell plates and process the short shell plates into short shells of a preset thickness and preset size;

[0022] The short shell is inserted from the closed end of the bottom of the box, and the interface end of the short shell is guided by the guide ramp to slide and lock between the first step surface and the second step surface.

[0023] As a preferred embodiment of a tank bottom assembly forming method, when processing the guide slope, the width of the guide slope in the radial direction of the transition ring is determined according to the outer perimeter of the transition ring and the inner perimeter of the short shell, wherein the outer perimeter of the transition ring is a, the inner perimeter of the short shell is b, and the width of the guide slope in the radial direction of the transition ring is c, and c is in the range of (ab) / 6 to (ab) / 5.

[0024] As a preferred embodiment of a tank bottom assembly forming method, when a third step surface is formed between the guide slope and the outer wall of the tank bottom, the connection between the third step surface and the tank bottom is processed into an arc-shaped chamfer.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention provides a tank bottom assembly, comprising a tank bottom and a transition ring. By using an integrally molded bottom and transition ring, the material uniformity of the bottom and transition ring is improved, resulting in better structural strength and reducing the number of welds, thus increasing the structural strength and production efficiency of the tank bottom assembly. Furthermore, by providing a first and second stepped surface on the outer wall of the transition ring, a limiting and docking interface is provided for subsequent assembly of the short shell. The second stepped surface, perpendicular to the first stepped surface, effectively holds the short shell in place, providing good support and limiting, preventing wobbling after assembly, improving installation accuracy, controlling the form and position tolerances of the tank bottom assembly, and ensuring the quality and reliability of the tank bottom assembly. Simultaneously, by providing a guide slope, subsequent assembly of the short shell is guided smoothly and quickly, saving assembly time and improving assembly efficiency and accuracy.

[0027] The present invention also provides a storage tank, which includes a cylindrical section and the aforementioned storage tank bottom assembly. By adopting a storage tank bottom assembly with better structural strength, the storage tank has higher reliability in use; at the same time, the structure of the storage tank bottom assembly is easy to assemble, which can effectively improve the production efficiency of the storage tank.

[0028] This invention also provides a method for forming a tank bottom assembly. By first fixing the outer ring of the plate and processing the inner ring, and then fixing the inner ring and processing the outer ring, the tank bottom and the transition section can be integrally formed, thereby improving the structural strength of the tank bottom assembly. At the same time, spinning is used when forming the tank bottom and the transition ring, which helps to strengthen the surface structure of the tank bottom and the transition ring, thereby improving the structural strength. It also eliminates the need for molds and mold assembly time, which helps to save production costs and facilitates customized design and production, providing better flexibility. Attached Figure Description

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

[0030] Figure 1 This is a schematic diagram of the structure of a storage tank provided in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of a tank bottom assembly provided in an embodiment of the present invention;

[0032] Figure 3 yes Figure 2 Enlarged view of section A;

[0033] Figure 4 This is a partial structural cross-section of a storage tank provided in an embodiment of the present invention. Figure 1 ;

[0034] Figure 5 This is a partial structural cross-section of a storage tank provided in an embodiment of the present invention. Figure 2 (Short shell not shown);

[0035] Figure 6 yes Figure 5 Enlarged view of section B;

[0036] Figure 7 This is a flow chart of a tank bottom assembly forming method provided in an embodiment of the present invention. Figure 1 ;

[0037] Figure 8 This is a flow chart of a tank bottom assembly forming method provided in an embodiment of the present invention. Figure 2 ;

[0038] Figure 9 This is a schematic diagram of the structure during the processing of the inner ring of the plate in a method for forming a tank bottom assembly according to an embodiment of the present invention;

[0039] Figure 10 This is a schematic diagram of the structure of the outer ring of the plate in a method for forming a tank bottom assembly according to an embodiment of the present invention.

[0040] In the picture:

[0041] 1. Box bottom; 2. Transition ring; 3. First step surface; 4. Second step surface; 5. Guide slope; 6. Short shell; 7. Cylindrical section; 8. Clamping mechanism; 81. Upper clamping plate; 82. Lower clamping plate; 9. Clamping block; 10. Spinning wheel. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0043] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature 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.

[0045] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used solely for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In the description of the present invention, unless otherwise stated, "a plurality of" means two or more. Furthermore, the terms "first" and "second" are merely used for descriptive distinction and have no special meaning.

[0046] The tank bottom assembly is a critical component of the rocket propellant tank, typically assembled from a tank bottom, a transition ring, and a short shell through welding. The tank bottom connects to the cylindrical shell section via the transition ring, and the structural strength of the tank bottom and the connection strength between the bottom and the transition ring determine the load-bearing capacity of the rocket propellant tank. The tank bottom and transition ring are often welded together from multiple segments, resulting in numerous weld seams throughout the assembly, significantly impacting its structural efficiency and stability. Furthermore, while existing technologies incorporate stepped surfaces on the transition ring for connection with the short shell, the short shell and transition ring use an interference fit. When the tank bottom has a large ellipticity, the butt joint between the short shell and transition ring becomes difficult, and insufficient control over dimensional and positional tolerances can easily lead to misalignment during subsequent welding, affecting quality.

[0047] Based on the above-mentioned technical problems, this embodiment provides a tank bottom component 1, such as... Figures 1 to 6 As shown, the tank bottom 1 assembly includes a tank bottom 1 and a transition ring 2. The transition ring 2 is located at the open end of the tank bottom 1 and is integrally formed with the tank bottom 1. The outer wall of the transition ring 2 has a vertically arranged first step surface 3 and a second step surface 4. The first step surface 3 is arranged radially along the transition ring 2, and the second step surface 4 is inclined towards the outer wall of the tank bottom 1 away from the first step surface 3, forming a guide slope 5. By setting the tank bottom 1 and the transition ring 2 as integrally formed, the material uniformity of the tank bottom 1 and the transition ring 2 is better, the structural strength is better, and the number of welds can be reduced, thereby improving the structural strength and production efficiency of the tank bottom 1 assembly. Furthermore, by setting the first step surface 3 and the second step surface 4 on the outer wall of the transition ring 2, a limiting and docking interface is provided for the subsequent assembly of the short shell 6. The second step surface 4 is perpendicular to the first step surface 3, which can effectively hold the short shell 6, providing a good supporting and limiting effect, preventing shaking after the short shell 6 is assembled, improving installation accuracy, controlling the form and position tolerances of the tank bottom 1 assembly, and thus ensuring the quality and reliability of the tank bottom 1 assembly. Meanwhile, by setting the guide slope 5, the short shell 6 can be smoothly and quickly connected under the guidance of the guide slope 5 during subsequent assembly, saving assembly time and improving assembly efficiency and accuracy; and the bottom 1 of the tank is semi-finished, and the guide slope 5 is precisely machined, so that the circumferential force is distributed more evenly, which can effectively avoid misalignment during the welding of the short shell 6, thus ensuring strict control of form and position tolerances and improving the quality of the tank bottom 1 component.

[0048] For example, the bottom of the box 1 is ellipsoidal, and the thickness of the bottom of the box 1 is 3mm-7mm, such as 3mm, 4mm, 5mm, 6mm, 7mm, etc.; the ellipsoidal module design range is 1.4-2, such as 1.4, 1.5, 1.6, 1.8, 2, etc., specifically set according to actual needs; the inner circle of the transition ring 2 is circular, and the diameter of the transition ring 2 ranges from 1.4m to 5.2m, such as 1.4, 3, 4, 5.2, etc.

[0049] Specifically, such as Figures 3 to 6 As shown, the tank bottom 1 assembly also includes a short shell 6, which is fitted onto the outside of the tank bottom 1. The interface end of the short shell 6 abuts against the first step surface 3 and the second step surface 4. The short shell 6 is cylindrical. When the short shell 6 is fitted into the tank body from the closed end of the tank bottom 1, one end of the short shell 6 is guided by the guide slope 5 to slide to its end face abutting against the first step surface 3, and the inner side wall of the short shell 6 abuts against the second step surface 4.

[0050] In this embodiment, depending on the size of the guide ramp 5 and the thickness of the box bottom 1, a third step surface can be formed between the guide ramp 5 and the outer wall of the box bottom 1, or it can be a circular arc transition. The width of the guide ramp 5 in the radial direction of the transition ring 2 is set according to the circumference of the transition ring 2 and the short shell 6, wherein the width of the guide ramp 5 in the radial direction of the transition ring 2 is c, the outer edge circumference of the transition ring 2 is a, the inner edge circumference of the short shell 6 is b, and c is in the range (ab) / 6 to (ab) / 5. The height of the guide ramp 5 in the axial direction of the transition ring 2 is determined according to the height of the second step surface 4 in the axial direction of the transition ring 2. For example, the height of the guide ramp 5 in the axial direction of the transition ring 2 is about half of the height of the second step surface 4 in the axial direction of the transition ring 2. The slope of the guide slope 5 can be determined by the width of the guide slope 5 in the radial direction of the transition ring 2 and the height of the guide slope 5 in the axial direction of the transition ring 2. By controlling the machining dimensions of the guide slope 5, the guide slope 5 can play a good guiding role for the subsequent assembly of the short shell 6, while avoiding the short shell 6 from getting stuck at the third step surface between the guide slope 5 and the outer wall of the box bottom 1 during assembly.

[0051] For example, the first step surface 3 has a radial width of 4 mm in the transition ring 2, the second step surface 4 has an axial height of 3 mm in the transition ring 2, and the guide slope 5 has a radial width of 0.5 mm in the transition ring 2 and an axial height of 3 mm in the transition ring 2. Of course, in other embodiments, the dimensions of the first step surface 3, the second step surface 4, and the guide slope 5 are not limited to the above example and are set according to actual needs.

[0052] like Figures 1 to 3 As shown, this embodiment also provides a storage tank, which includes a cylindrical section 7 and the aforementioned storage tank bottom 1 assembly. The cylindrical section 7 is connected to one end of the transition ring 2 opposite to the bottom 1. Specifically, one of the aforementioned storage tank bottom 1 assemblies is respectively provided at each end of the cylindrical section 7. By using a storage tank bottom 1 assembly with better structural strength, the storage tank has higher reliability in use; at the same time, the structure of the storage tank bottom 1 assembly is easy to assemble, which can effectively improve the production efficiency of the storage tank.

[0053] like Figures 7 to 10 As shown, this embodiment also provides a method for forming a tank bottom 1 component, which includes the following steps:

[0054] Prepare the boards;

[0055] The outer ring of the fixed constraint plate is sheared and spun to the contour of the target box bottom 1 by a spinning wheel 10 to obtain the first formed part. In this embodiment, the outer ring of the plate is clamped by a clamping mechanism 8. For example, the clamping mechanism 8 includes an upper clamping plate 81 and a lower clamping plate 82. The upper clamping plate 81 and the lower clamping plate 82 can move closer or further apart to clamp or release the plate. The structure is simple and easy to operate. After clamping the outer ring of the plate, the plate is spun to the contour of the target box bottom 1 by a moldless shearing and spinning process. When the plate is spun by the spinning wheel 10, the inner surface structure of the box bottom 1 is strengthened, which is beneficial to improving the structural strength and is more environmentally friendly to the use of the structure. At the same time, the mold is eliminated, which saves costs and assembly time. The absence of mold restrictions also facilitates customized design and production.

[0056] The outer ring constraint of the first forming part is released, and the inner ring constraint of the first forming part is fixed. The outer ring of the first forming part is then formed into a column segment by flanging and spinning using a spinning wheel 10. In this embodiment, fixing the inner ring can be achieved simply by using two clamping blocks 9 that can move closer and further apart, which is convenient, quick, and low-cost. After clamping the inner ring of the sheet metal, the outer ring is flanged and spun into a column segment using a moldless flanging and spinning process, which is the state before the transition ring 2 has an interface. Furthermore, the outer surface structure of the transition ring 2 is strengthened by spinning using the spinning wheel 10, which is beneficial to improving the structural strength and is more environmentally friendly to the structure. At the same time, the mold is eliminated, which saves costs and assembly time. The absence of mold restrictions also facilitates customized design and production.

[0057] A mating interface is machined on the outer wall of the column segment to obtain an integrally formed tank bottom 1 and transition ring 2. The integrally formed tank bottom 1 and transition ring 2 result in better material uniformity and structural strength, and can reduce the number of welds, thereby improving the structural strength and production efficiency of the tank bottom 1 assembly.

[0058] Specifically, after the column segment is formed on the outer ring of the first formed part, the bottom part 1 is machined to achieve a preset thickness. For example, the bottom part 1 is machined to a thickness of 3mm-7mm using a lathe. The machining of the bottom part 1 thickness is preferably performed before machining the mating interface, which facilitates the machining of the mating interface and improves the machining accuracy of the mating interface.

[0059] More specifically, during the machining of the docking interface, a first step surface 3 radially arranged along the transition ring 2 and a second step surface 4 perpendicular to the first step surface 3 are machined on the outer wall of the column segment. A guide slope 5 is machined at the end of the second step surface 4 facing away from the first step surface 3 and towards the bottom of the box 1. The perpendicularity of the second step surface 4 to the first step surface 3 effectively holds the short shell 6 subsequently assembled on the bottom of the box 1, providing good support and limiting, preventing wobbling after assembly of the short shell 6, improving installation accuracy, controlling the form and position tolerances of the bottom of the box 1 assembly, thereby ensuring the quality and reliability of the bottom of the box 1 assembly. Simultaneously, by setting the guide slope 5, the short shell 6 can be smoothly and quickly docked under the guidance of the guide slope 5, saving assembly time and improving assembly efficiency and accuracy. Furthermore, the bottom of the box 1 is semi-finished, and the guide slope 5 is precisely machined, resulting in a more uniform distribution of circumferential force, effectively preventing misalignment during the welding of the short shell 6, thus ensuring strict control of form and position tolerances and improving the quality of the bottom of the box 1 assembly.

[0060] Furthermore, after the integrated bottom 1 and transition ring 2 are formed, solution aging heat treatment is performed. Since solution aging heat treatment is a relatively mature existing technology, it will not be described in detail here.

[0061] Furthermore, the method for forming the tank bottom 1 component also includes the following steps:

[0062] Prepare short shell 6 sheet material and process the short shell 6 sheet material into short shell 6 with preset thickness and preset size;

[0063] The short shell 6 is inserted into the closed end of the box bottom 1. The interface end of the short shell 6 is guided by the guide ramp 5 and slides to be stuck between the first step surface 3 and the second step surface 4. The short shell 6 is cylindrical. When the short shell 6 is inserted into the box body from the closed end of the box bottom 1, one end of the short shell 6 is guided by the guide ramp 5 to slide until its end face abuts against the first step surface 3, and the inner side wall of the short shell 6 abuts against the second step surface 4.

[0064] In this embodiment, depending on the size of the guide slope 5 and the thickness of the box bottom 1, a third step surface can be formed between the guide slope 5 and the outer wall of the box bottom 1, or it can be a circular arc transition. After the box bottom 1 is machined to the preset thickness, the column segment is then machined. The width of the guide slope 5 in the radial direction of the transition ring 2 is set according to the circumference of the transition ring 2 and the short shell 6. Specifically, the width of the guide slope 5 in the radial direction of the transition ring 2 is c, the outer edge circumference of the transition ring 2 is a, the inner edge circumference of the short shell 6 is b, and c is in the range of (ab) / 6 to (ab) / 5. The height of the guide slope 5 in the axial direction of the transition ring 2 is determined according to the height of the second step surface 4 in the axial direction of the transition ring 2. For example, the height of the guide slope 5 in the axial direction of the transition ring 2 is about half the height of the second step surface 4 in the axial direction of the transition ring 2. The slope of the guide slope 5 can be determined by the width of the guide slope 5 in the radial direction of the transition ring 2 and the height of the guide slope 5 in the axial direction of the transition ring 2. By controlling the machining dimensions of the guide slope 5, the guide slope 5 can play a good guiding role for the subsequent assembly of the short shell 6, while avoiding the short shell 6 from getting stuck at the third step surface between the guide slope 5 and the outer wall of the box bottom 1 during assembly.

[0065] Preferably, when a third step surface is formed between the guide slope 5 and the outer wall of the box bottom 1, the connection between the third step surface and the box bottom 1 is processed into an arc-shaped chamfer to improve the structural strength and thus improve the reliability of the box bottom 1 component. At the same time, the arc-shaped chamfer can also prevent the short shell 6 from getting stuck at the third step surface during assembly, thus improving the smoothness of assembly.

[0066] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A storage tank bottom assembly, characterized in that, include: Bottom of the box; A transition ring is disposed at the open end of the bottom of the box and is integrally formed with the bottom of the box. The outer wall of the transition ring has a first step surface and a second step surface that are vertically arranged. The first step surface is arranged radially along the transition ring. The second step surface is inclined towards the outer wall of the bottom of the box away from the outer edge of the first step surface to form a guide slope. A third step surface is formed between the guide slope and the outer wall of the bottom of the box. The connection between the third step surface and the bottom of the box is an arc-shaped chamfer. A short shell is fitted over the bottom of the box, and the interface end of the short shell abuts against the first stepped surface and the second stepped surface; The outer perimeter of the transition ring is a, the inner perimeter of the short shell is b, and the width of the guide slope in the radial direction of the transition ring is c, where c is in the range of (ab) / 6 to (ab) / 5.

2. A storage tank, characterized in that, It includes a cylindrical section and the tank bottom assembly as described in claim 1, wherein the cylindrical section is connected to one end of the transition ring opposite to the tank bottom.

3. A method for forming a tank bottom assembly, characterized in that, Includes the following steps: Prepare the boards; The outer ring of the sheet metal is fixed and constrained, and the sheet metal is sheared and spun to the contour of the target box bottom by a spinning wheel to obtain the first formed part; Release the outer ring constraint of the first forming part and fix the inner ring constraint of the first forming part. Then, use the spinning wheel to flanging and spinning the outer ring of the first forming part to form a column segment. A mating interface is machined on the outer wall of the column section to obtain an integrally formed box bottom and transition ring; When processing the docking interface, a first step surface and a second step surface perpendicular to the first step surface are processed on the outer wall of the column segment, and a guide slope is processed at the end of the second step surface away from the first step surface and towards the bottom of the box. Prepare short shell plates and process the short shell plates into short shells of a preset thickness and preset size; The short shell is inserted from the closed end of the bottom of the box, and the interface end of the short shell is guided by the guide ramp to slide and get stuck between the first step surface and the second step surface; When processing the guide slope, the width of the guide slope in the radial direction of the transition ring is determined according to the outer perimeter of the transition ring and the inner perimeter of the short shell, wherein the outer perimeter of the transition ring is a, the inner perimeter of the short shell is b, and the width of the guide slope in the radial direction of the transition ring is c, and c is in the range of (ab) / 6 to (ab) / 5. When a third step surface is formed between the guide slope and the outer wall of the box bottom, the connection between the third step surface and the box bottom is processed into an arc-shaped chamfer.

4. The method for forming the tank bottom assembly according to claim 3, characterized in that, After the column segment is formed on the outer ring of the first molded part, the bottom part of the box is processed so that the thickness of the bottom of the box reaches the preset thickness.

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