Assembling and welding method for 3800 lift type common-bottom storage box

Abstract

The invention provides a 3800 lift type common-bottom storage box assembling and welding method which comprises a binding support circumferential shape and position size control method which comprises the steps that binding supports are installed in the state of a force bearing ring, quadrant identifiers are added to a shell section supporting ring and a transition ring, and when the force bearing ring is assembled, one binding support serves as a benchmark, the quadrant identifiers are added to the shell section supporting ring and the transition ring, and the quadrant identifiers are added to the shell section supporting ring and the transition ring; the binding support and the rear end frame are assembled with marked scribed lines on the transition ring so as to meet the circumferential precision of the binding support and the rear end frame; the axial shape and position size control method for the binding support comprises the steps that the binding support is installed in the state of the force bearing rings, and the axial distance size precision between the force bearing rings and the axial distance size precision between the force bearing rings and the rear end frame are met by controlling the girth welding shrinkage amount. According to the horizontal assembling and welding device, horizontal assembling and welding of the box body of the ultra-long common-bottom storage box with the diameter of 3800 m can be achieved, the equipment investment cost is low, the problems of assembling and welding deformation of the ultra-long common-bottom storage box and precision coordination control over a binding support are solved, and the technical blank of novel storage box product development is filled up.

Description

Technical Field

[0001] The present application belongs to the field of rocket tank welding technology, and in particular to a 3800-lift common-bottom tank assembly welding method. Background Art

[0002] In order to meet the development needs of a certain aerospace model in my country, a Φ3800mm lifting common bottom tank was designed. The tank consists of a short shell, a tank bottom, a front tank barrel section, a common bottom, a rear tank barrel section, a bearing ring, etc. The theoretical diameter of the tank is Φ3800mm, and the tank length reaches 23000-26000mm. The front and rear bottoms and the common bottom are ellipsoidal bottoms, and the common bottom is a single-layer structure. There are multiple binding supports designed on the bearing ring to achieve connection with the product wing.

[0003] Compared with the mature Φ3350mm rocket tank products, the product object not only changes its diameter from Φ3350mm to Φ3800mm, but also reaches a tank length of more than 23000mm, and is a double-cavity common bottom structure tank, the tank structure is more complex. At the same time, considering the requirements for the installation of wing binding supports on the load-bearing ring structure, the requirements for the control of the shape and position dimensions of the tank welding are more stringent, but there is currently no technical solution for the assembly welding and shape and position dimensional control of tanks with similar structures in China, and there are problems such as deformation of the super-long common bottom tank during welding and difficulty in coordinating the accuracy of the binding supports. Summary of the invention

[0004] In view of this, the present application aims to propose a 3800-liter common-bottom tank assembly and welding method to solve the problems of deformation during assembly and welding of ultra-long common-bottom tanks and difficulty in coordinating and controlling the accuracy of binding supports.

[0005] To achieve the above purpose, the technical solution of this application is implemented as follows:

[0006] The present application provides a 3800-liter common bottom tank assembly welding method, wherein the common bottom tank is assembled and welded by an oxygen tank and a methane tank, and a plurality of bearing rings are arranged at the cylinder section of the methane tank. The method comprises:

[0007] A method for controlling the circumferential shape and position dimensions of a binding support, the control method comprising installing the binding support in a load-bearing ring state, adding quadrant markings on the shell segment support ring and the transition ring, and using one of the binding supports as a reference when assembling the load-bearing ring, and assembling with the marked lines on the transition ring to meet the circumferential accuracy of the binding support and the rear end frame;

[0008] A method for controlling the axial shape and position dimensions of a binding support includes installing the binding support in a load-bearing ring state, and controlling the shrinkage of the annular seam welding to meet the axial spacing dimension accuracy between the load-bearing rings and between the load-bearing rings and the rear end frame.

[0009] Furthermore, the method for controlling the circumferential shape and position dimensions of the binding support includes:

[0010] The first load-bearing ring is assembled and welded to the corresponding shell segment support ring. A first binding support is arranged on the first load-bearing ring. A quadrant line is engraved on the shell segment support ring. The first binding support is used as a reference and aligned with the quadrant line on the shell segment support ring to ensure that the first binding support arranged on the first load-bearing ring is in a circumferential position in the entire box.

[0011] Furthermore, it also includes:

[0012] The second load-bearing ring is assembled and welded to the corresponding shell segment support ring. A second binding support is provided on the second load-bearing ring. The second binding support is used as a reference and aligned with the quadrant line on the shell segment support ring to ensure the circumferential relative position of the first binding support and the second binding support.

[0013] Furthermore, it also includes:

[0014] The rear bottom assembly is assembled and welded, and the shell segment support ring is replaced with a transition ring. The assembly is performed according to the position corresponding to the second binding support set on the rear end frame and the quadrant line engraved by the transition ring to ensure the relative position of the rear end frame and the binding support in the circumferential direction.

[0015] Furthermore, the method for controlling the axial shape, position and dimension of the binding support comprises:

[0016] Welding of the first bearing ring and the third methane cylinder section: Based on the theoretical distance between the first bearing ring and the rear end frame and the theoretical length of the tank, the distance between the end face of the third methane cylinder section and the front end frame is calculated, and the milling length of the third methane cylinder section is calculated in combination with the empirical value of the welding shrinkage and the measured distance between the end face of the third methane cylinder section and the front end frame;

[0017] The first methane cylinder section is milled before welding to ensure the relative position of the first bearing ring in the entire box.

[0018] Furthermore, it also includes:

[0019] The second bearing ring is welded to the fourth methane cylinder section: after the first bearing ring is welded, the distance between its end face and the front end frame is measured, and the assembly welding of the fourth methane cylinder section is performed. After the fourth methane cylinder section is welded, the milling length of the fourth methane cylinder section is calculated based on the theoretical length of the tank, the actual distance between the first bearing ring and the front end face, the measured length between the first bearing ring and the second bearing ring, the theoretical distance between the second bearing ring and the rear end frame, and the empirical value of welding shrinkage;

[0020] The end face of the fourth methane cylinder section is milled to ensure the relative position of the first bearing ring and the second bearing ring.

[0021] Furthermore, the sixth methane cylinder segment is welded to the rear bottom assembly: after the second bearing ring is welded, the fifth methane cylinder segment is assembled and welded; after the fifth methane cylinder segment is welded, the milling amount of the sixth methane cylinder segment is calculated based on the theoretical distance between the second bearing ring and the rear end frame and the actual distance between the second bearing ring and the rear end frame, and then the tank is sealed and welded.

[0022] Furthermore, it also includes:

[0023] The binding support and the bearing ring are pre-positioned by means of positioning pins, and the binding support is expanded toward the bearing ring so that the bearing ring and the binding support connection hole are coaxial and correspond one to one;

[0024] Disassemble the binding support, tap the connecting holes on the load-bearing ring, expand and ream the connecting holes on the binding support, and connect the binding support and the load-bearing ring with bolts.

[0025] Furthermore, the support structure on the shell support ring is controlled at the same time so that the theoretical diameter of the support is consistent with the theoretical inner surface diameter of the barrel segment. The shell support ring is arranged on the non-welded section of the barrel segment for support to ensure the assembly roundness and coaxiality of the barrel segment.

[0026] Furthermore, a corresponding plurality of limiting devices are arranged on the shell segment supporting ring supporting tray, and the plurality of limiting devices are used to limit the outer contour of the bearing ring to a theoretical circle position.

[0027] Compared with the prior art, the 3800-liter common-bottom tank assembly welding method described in this application has the following beneficial effects:

[0028] The 3800-liter common-bottom tank assembly and welding method described in the present application can realize the horizontal assembly and welding of my country's new Φ3800m ultra-long common-bottom structure tank body. The equipment investment cost is low, and the problem of deformation during assembly and welding of ultra-long common-bottom tanks and the coordinated control of the accuracy of binding supports is solved, filling the technical gap in the development of new tank products. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0030] Figure 1 This is a schematic diagram of the circumferential seam welding of the oxygen box barrel section described in an embodiment of the present application;

[0031] Figure 2 This is a schematic diagram of the oxygen box sealing ring seam welding described in an embodiment of the present application;

[0032] Figure 3 This is a schematic diagram of the welding of the methane tank barrel section described in the embodiment of the present application;

[0033] Figure 4 This is a schematic diagram of the methane box sealing ring seam welding according to the embodiment of the present application;

[0034] Figure 5 This is a plan view of a straight welding expansion ring according to an embodiment of the present application;

[0035] Figure 6 This is a schematic plan view of the box sealing annular seam welding expansion ring described in an embodiment of the present application;

[0036] Figure 7 This is a schematic plan view of the shell segment support ring described in an embodiment of the present application;

[0037] Figure 8 This is a schematic diagram of installing a binding support in the state of a load-bearing ring as described in an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0039] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0040] See also Figures 1 to 4 As shown, this embodiment provides a 3800-liter common bottom tank assembly welding method. The common bottom tank is assembled and welded by an oxygen tank and a methane tank. A plurality of bearing rings are arranged at the cylinder section of the methane tank. Therefore, when assembling and welding the ultra-long tank horizontally, this embodiment adopts an integrated process flow, which is as follows:

[0041] The front bottom assembly is put on the shelf, the first barrel section of the oxygen box is assembled and welded, and the second barrel section of the oxygen box, the third barrel section of the oxygen box, the fourth barrel section of the oxygen box, and the fifth barrel section of the oxygen box are assembled and welded in sequence. The common bottom and methane box barrel section assembly are put on the shelf, the oxygen box is sealed and welded, the second barrel section of the methane box is assembled and welded, the third barrel section of the methane box is assembled and welded, the first load-bearing ring is assembled and welded, the fourth barrel section of the methane box is assembled and welded, the second load-bearing ring is assembled and welded, the fifth barrel section of the methane box is assembled and welded, the sixth barrel section of the methane box is assembled, the rear bottom assembly is assembled, the distance from the first load-bearing ring and the binding support on the second load-bearing ring to the rear end frame is precisely measured for excess precision milling and size remeasurement, the methane box is sealed and welded, and the storage tank is precisely measured after being removed from the shelf.

[0042] It should be noted that this embodiment only takes the first load-bearing ring, the second load-bearing ring, the first binding support, and the second binding support as examples for explanation, and does not specifically limit the number of the above components, which will not be elaborated here.

[0043] Combined with the horizontal assembly welding requirements of the super-long cylinder section box ring seam welding, the Φ3800mm box ring seam inner support ring, shell section support ring, auxiliary support vehicle and other tooling are used to meet the box assembly welding requirements. The specific combination is described as follows.

[0044] 1. For the annular seams of oxygen box and methane box, such as Figure 5 As shown, this embodiment adopts a straight welded inner support ring, which supports a theoretical diameter of Φ3790mm, and a single-side preset 1mm welding reverse deformation. It adopts a split support block mode, and a single support block can provide a support force of not less than 300Kg, meeting the rigid support requirements of the box barrel section with a thickness of 12mm-15mm.

[0045] 2. For the bottom / cylinder annular seams of oxygen and methane boxes, such as Figure 6 As shown, this embodiment adopts a conical welded inner support ring, and the pad surface can fit the gradual ellipsoidal surface of the box bottom / barrel section annular seam, supporting a theoretical diameter of Φ3790mm, and a single-side preset 1mm welding reverse deformation. At the same time, a detachable support block mode is adopted, and a single support block can provide a supporting force of not less than 300Kg. After the box is sealed and welded, it can be disassembled and removed from the box.

[0046] 3. For the welding process of the box ring seam assembly, such as Figure 7 As shown, this embodiment adopts a shell segment support ring, which can support a theoretical diameter of Φ3789mm, which is consistent with the theoretical inner surface diameter of the barrel segment. It supports the non-welded section of the barrel segment to ensure the assembly roundness and coaxiality of the barrel segment. It adopts pneumatic tightening to achieve rapid clamping and disassembly.

[0047] At the same time, four limit devices are designed at the support tray of the shell segment support ring. The limit devices are evenly installed on the support tray. When the bearing ring is assembled, the position of the outer contour of the bearing ring is limited to the theoretical Φ3818mm circle position, thereby ensuring the good coaxiality of the bearing ring assembly and the tooling benchmark.

[0048] It should be noted that the limiting device described in this embodiment is a limiting block, and the limiting block is fixed to the support tray by fixing bolts to effectively limit the outer contour of the load-bearing ring. This embodiment does not specifically limit the shape and structure of the limiting block. The ability to achieve the limiting function is within the protection scope of this embodiment and will not be further elaborated.

[0049] In view of the particularity of product structure and usage requirements, this embodiment designs a method for regulating the shape, position and size consistency of an ultra-long common bottom storage tank with a bearing ring structure, including:

[0050] 1. Method for ensuring the dimensional accuracy of the bundled support in the single bearing ring state

[0051] During the processing of the bearing ring, according to the overall design of the binding support assembly position, combined with the binding support connection hole position, the precision five-axis CNC processing equipment is used to pre-make the binding support connection bolt hole bottom hole (hole diameter is 0.5mm smaller than the tapping bottom hole diameter) in the bearing ring state (part state). In the part state, according to the size requirements of the design drawing, all bolt connection holes are made for the binding support, and the connection hole diameter is consistent with the bearing ring hole diameter. During the processing of the bearing ring and the binding support connection bolt hole, the connection hole processing accuracy is strictly controlled.

[0052] After the bearing ring and the binding support parts are processed, the binding support and the bearing ring are pre-positioned using the positioning pin, and the hole is expanded from the binding support to the bearing ring (to the tapping bottom hole diameter) using a drill bit to achieve the coaxial and one-to-one correspondence between the bearing ring and the binding support connection hole. Subsequently, the binding support is disassembled, the bolt connection hole on the bearing ring is tapped, and the bolt connection hole on the binding support is expanded and reamed to the design requirements, and finally the binding support and the bearing ring are connected with bolts.

[0053] 2. Process precision control method of bearing ring welding assembly process

[0054] By effectively controlling the tank welding process, the assembly accuracy of the bundling support in the whole tank state can be guaranteed. By adding marking lines on the transition ring and the shell support ring (set at the non-welded end of the barrel), the first bundling support and the second bundling support are used as the reference for assembly. The circumferential accuracy of the bundling support is guaranteed by the accuracy of the equipment and tooling, and the axial position of the bundling support is guaranteed by the shrinkage during the welding process. The following will discuss the control schemes for the circumferential and axial assembly accuracy of the bundling support.

[0055] A. Circumferential position accuracy control

[0056] Install the binding support under the load-bearing ring state (the structural diagram of the load-bearing ring and the binding support is as shown in Figure 8 As shown in the figure, add quadrant marks on the shell support ring and transition ring. When assembling the load-bearing ring, use one of the binding supports as a reference and assemble it with the marked line on the transition ring to ensure the circumferential accuracy requirements of the binding support and the rear end frame, as follows:

[0057] (1) Assembly and welding of the first bearing ring and the shell support ring: The shell support ring is positioned and connected to the equipment through the positioning pin hole to ensure the relative position of the equipment and the shell support ring. The position line is engraved at the corresponding position of the shell support ring, and the first binding support is used as a reference to align and assemble with the position line on the shell support ring to ensure the circumferential position of the binding support on the first bearing ring in the whole box. According to previous experience, the accuracy of a single position line assembly can be guaranteed to be ±0.5mm;

[0058] (2) Assembly and welding of the second bearing ring and the shell support ring: After the welding of the first bearing ring is completed, the fourth methane cylinder section is assembled and welded normally. When the second bearing ring is assembled and welded, the second binding support is used as the reference and assembled with the quadrant line on the shell support ring, thereby ensuring the circumferential position of the binding support on the second bearing ring. The assembly is carried out based on the quadrant line on the same shell support ring to ensure the circumferential relative position of the first bearing ring and the binding support on the second bearing ring. According to past experience, the accuracy of a single quadrant line assembly can be guaranteed to be ±0.5mm;

[0059] (3) Assembly and welding of the rear bottom assembly: After the welding of the second bearing ring is completed, assemble and weld the fifth methane cylinder section normally. Replace the shell support ring with the rear transition ring, and use the same positioning pin hole to position and connect it to the equipment to ensure the relative position of the rear transition ring and the equipment, and mark the position line corresponding to the position of the bundling support on the transition ring. When assembling and welding the rear bottom assembly, assemble it according to the position corresponding to the second bundling support on the rear end frame and the position line marked on the transition ring, thereby ensuring the relative position of the rear end frame and the bundling support (one or both) in the circumferential direction. According to past experience, the accuracy of a single position line assembly can be guaranteed to be ±0.5mm;

[0060] Considering the extreme case of assembly, the limit error of the circumferential position of the bearing ring is ±1.5mm. When assembling the second bearing ring and the rear bottom assembly, adaptive adjustments can be made according to the assembly conditions of the previous section to ensure the circumferential assembly accuracy.

[0061] B. Axial position accuracy control

[0062] Install the binding support in the state of the bearing ring segment, and control the shrinkage of the annular seam welding to ensure the axial spacing dimensional accuracy between the first bearing ring and the second bearing ring, and between the first bearing ring and the rear end frame, as follows:

[0063] (1) Welding of the first bearing ring and the third methane cylinder section: The distance L3 between the end face of the third methane cylinder section and the front end frame is calculated based on the theoretical distance L1 between the first bearing ring and the rear end frame and the theoretical length L2 of the tank. The milling length L3 of the third methane cylinder section is obtained by combining the empirical value Δh of the welding shrinkage and the measured distance L3′ between the end face of the third methane cylinder section and the front end frame. 铣 .

[0064] L3 铣 =L3′-L3+Δh=L3′-(L2-L1)+Δh

[0065] Before welding, the first methane cylinder section is milled to ensure the relative position of the first bearing ring in the whole box. According to previous welding experience, the fluctuation of welding shrinkage is ±1mm, thereby ensuring the distance between the first bearing ring and the rear end frame;

[0066] (2) Welding of the second bearing ring and the fourth methane cylinder section: After the first bearing ring is welded, measure the distance between its end face and the front frame, and then proceed with the assembly welding of the fourth methane cylinder section. After the fourth methane cylinder section is welded, calculate the milling length L4 of the fourth methane cylinder section based on the theoretical length L2 of the tank, the actual distance L4 between the first bearing ring and the front face, the measured length L5 between the first bearing ring and the second bearing ring, the theoretical distance L6 between the second bearing ring and the rear frame, and the empirical value Δh of welding shrinkage. 铣 .

[0067] L4 铣 =(L2-L4-L6)-L5+Δh

[0068] The end face of the fourth methane cylinder section is milled to ensure the relative position of the first bearing ring and the second bearing ring. Based on the fluctuation range of welding shrinkage of ±1mm, the axial position of the two bearing rings can be guaranteed to be ±1mm;

[0069] (3) Welding of the sixth methane cylinder section and the rear bottom assembly: After the second bearing ring 2 is welded, the assembly welding of the fifth methane cylinder section is carried out normally. After the fifth methane cylinder section is welded, the milling amount L6 of the sixth methane cylinder section is calculated based on the principle of giving priority to the axial position of the binding support according to the theoretical distance L6 between the second bearing ring and the rear end frame and the actual distance L6′ between the second bearing ring and the rear end frame. 铣 , seal and weld the centralized storage tank.

[0070] L6 铣 =(L6′-L6)+Δh

[0071] According to empirical values, the fluctuation range of welding shrinkage of a single annular seam is ±1mm. Before welding the first bearing ring and the second bearing ring, the second methane cylinder section is milled according to the theoretical length. Therefore, the relative position of the two bearing rings requires an annular seam to ensure, and the axial relative position accuracy can be guaranteed to be ±1mm; the distance between the bearing ring and the rear end frame needs to be ensured by the sealing annular seam. Therefore, the axial position of a single bearing ring and the rear end frame can be guaranteed to be ±1mm, and the axial position of two bearing rings and the rear end frame can be guaranteed to be ±2mm.

[0072] This method can realize the horizontal assembly and welding of my country's new Φ3800m ultra-long common bottom structure tank body. The equipment investment cost is low, and it solves the problem of deformation during assembly and welding of ultra-long common bottom tanks and the coordination control of the accuracy of binding supports, filling the technical gap in the development of new tank products.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

[0074] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A 3800-liter common bottom tank assembly welding method, characterized in that: The common bottom storage tank is assembled and welded by an oxygen tank and a methane tank, and a plurality of bearing rings are arranged at the cylinder section of the methane tank. The method comprises: A method for controlling the circumferential shape and position dimensions of a binding support, the control method comprising installing the binding support in a load-bearing ring state, adding quadrant markings on the shell segment support ring and the transition ring, and using one of the binding supports as a reference when assembling the load-bearing ring, and assembling with the marked lines on the transition ring to meet the circumferential accuracy of the binding support and the rear end frame; A method for controlling the axial shape and position dimensions of a binding support includes installing the binding support in a load-bearing ring state, and controlling the shrinkage of the annular seam welding to meet the axial spacing dimension accuracy between the load-bearing rings and between the load-bearing rings and the rear end frame.

2. The method according to claim 1, characterized in that The method for controlling the circumferential shape and position dimensions of the binding support comprises: The first load-bearing ring is assembled and welded to the corresponding shell segment support ring. A first binding support is arranged on the first load-bearing ring. A quadrant line is engraved on the shell segment support ring. The first binding support is used as a reference and aligned with the quadrant line on the shell segment support ring to ensure that the first binding support arranged on the first load-bearing ring is in a circumferential position in the entire box.

3. The method according to claim 2, characterized in that Also includes: The second load-bearing ring is assembled and welded to the corresponding shell segment support ring. A second binding support is provided on the second load-bearing ring. The second binding support is used as a reference and aligned with the quadrant line on the shell segment support ring to ensure the circumferential relative position of the first binding support and the second binding support.

4. The method according to claim 3, characterized in that Also includes: The rear bottom assembly is assembled and welded, and the shell segment support ring is replaced with a transition ring. The assembly is performed according to the position corresponding to the second binding support set on the rear end frame and the quadrant line engraved by the transition ring to ensure the relative position of the rear end frame and the binding support in the circumferential direction.

5. The method according to claim 1, characterized in that The method for controlling the axial shape, position and size of the binding support comprises: Welding of the first bearing ring and the third methane cylinder section: Based on the theoretical distance between the first bearing ring and the rear end frame and the theoretical length of the tank, the distance between the end face of the third methane cylinder section and the front end frame is calculated, and the milling length of the third methane cylinder section is calculated in combination with the empirical value of the welding shrinkage and the measured distance between the end face of the third methane cylinder section and the front end frame; The first methane cylinder section is milled before welding to ensure the relative position of the first bearing ring in the entire box.

6. The method according to claim 5, characterized in that Also includes: The second bearing ring is welded to the fourth methane cylinder section: after the first bearing ring is welded, the distance between its end face and the front end frame is measured, and the assembly welding of the fourth methane cylinder section is performed. After the fourth methane cylinder section is welded, the milling length of the fourth methane cylinder section is calculated based on the theoretical length of the tank, the actual distance between the first bearing ring and the front end face, the measured length between the first bearing ring and the second bearing ring, the theoretical distance between the second bearing ring and the rear end frame, and the empirical value of welding shrinkage; The end face of the fourth methane cylinder section is milled to ensure the relative position of the first bearing ring and the second bearing ring.

7. The method according to claim 6, characterized in that Also includes: Welding of the sixth methane cylinder section and the rear bottom assembly: After the welding of the second bearing ring is completed, the fifth methane cylinder section is assembled and welded. After the welding of the fifth methane cylinder section is completed, the milling amount of the sixth methane cylinder section is calculated based on the theoretical distance between the second bearing ring and the rear end frame and the actual distance between the second bearing ring and the rear end frame, and then the tank is sealed and welded.

8. The method according to claim 1, characterized in that Also includes: The binding support and the bearing ring are pre-positioned by means of positioning pins, and the binding support is expanded toward the bearing ring so that the bearing ring and the binding support connection hole are coaxial and correspond one to one; Disassemble the binding support, tap the connecting holes on the load-bearing ring, expand and ream the connecting holes on the binding support, and connect the binding support and the load-bearing ring with bolts.

9. The method according to claim 1, characterized in that: At the same time, the support structure on the shell support ring is controlled so that the theoretical diameter of the support is consistent with the theoretical inner surface diameter of the barrel segment. The shell support ring is arranged at the non-welded section of the barrel segment for support to ensure the assembly roundness and coaxiality of the barrel segment.

10. The method according to claim 1, characterized in that: A plurality of corresponding limiting devices are arranged on the shell segment supporting ring supporting tray, and the plurality of limiting devices are used to limit the outer contour of the bearing ring to a theoretical circle position.

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