Method for processing steel cylinders of different thicknesses

Abstract

This invention discloses a method for processing steel cylinders of different thicknesses, including: Step S1, part cutting and processing: parts are cut using gas cutting or plasma cutting, with random sampling inspection performed on-site each time parts are cut; Step S2, cylinder rolling and recirculation process, including: Step S21, preparation work before cylinder rolling; Step S22, cylinder rolling; Step S23, longitudinal seam welding of the cylinder; Step S24, secondary rounding of the cylinder; Step S3, cylinder assembly, including: Step S31, pre-assembly requirements of the cylinder; Step S32, cylinder assembly construction process; Step S33, non-destructive testing of the cylinder weld; Step S34, cylinder precision control; Step S35, cylinder dimension measurement; Step S4, marking treatment of the cylinder, and the cylinder is put into storage after user inspection or final inspection. This invention solves the manufacturing problem of large-diameter steel cylinders of different thicknesses; reduces construction difficulty and improves manufacturing efficiency.

Description

Technical Field

[0001] This invention relates to the field of steel cylinder manufacturing technology, and in particular to a method for processing steel cylinders of different plate thicknesses. Background Technology

[0002] In wind turbine jacket projects, the central main body of the transition section is generally a large-diameter cylindrical structure, which can be composed of multiple pipe sections with different wall thicknesses. The plate thickness is 65-90mm, which is relatively thick, and the steel cylinder has a diameter of 7.5 meters, which is also quite large. The processing of this steel cylinder is difficult, costly, and time-consuming. To reduce construction difficulty and improve production efficiency and steel cylinder precision, it is necessary to provide a processing method for steel cylinders with different plate thicknesses, solving the problem of processing and manufacturing large-diameter steel cylinders with varying plate thicknesses. Summary of the Invention

[0003] The purpose of this invention is to provide a method for processing steel cylinders of different thicknesses, which solves the manufacturing problem of large-diameter steel cylinders of different thicknesses; reduces construction difficulty and improves manufacturing efficiency.

[0004] This invention is achieved through the following technical solution:

[0005] A method for processing steel cylinders of different plate thicknesses, comprising the following steps:

[0006] Step S1, Parts cutting and processing: Parts are cut by gas cutting or plasma cutting, and random sampling is carried out on site each time parts are cut;

[0007] Step S2, the cylindrical tube rolling and rewinding processes, respectively include:

[0008] Step S21: Preparations before cylinder rolling;

[0009] Step S22: Cylindrical rolling;

[0010] Step S23: Welding the longitudinal seam of the cylinder;

[0011] Step S24: Secondary rounding of the cylinder;

[0012] Step S3, Assembly of cylindrical pipe fittings, including:

[0013] Step S31, Pre-assembly requirements for cylindrical components;

[0014] Step S32, Cylindrical assembly construction process;

[0015] Step S33: Non-destructive testing of cylindrical welds;

[0016] Step S34: Cylinder precision control;

[0017] Step S35: Measure the cylinder dimensions;

[0018] Step S4: The cylinder is marked with a spray mark. After the cylinder is inspected by the user or undergoes final inspection, it is put into storage.

[0019] As a further improvement to the technical solution of the present invention, in step S1, the parts are measured and inspected using a steel ruler or tape measure. The allowable deviations for this type of cut parts are: the allowable range for the width and length of the parts is ±1.5 mm; the cut flatness is 0.05-2.0 mm; the cut depth is no more than 0.3 mm; and the depth of the local notch is no more than 1.0 mm.

[0020] As a further improvement to the technical solution of the present invention, the preparatory work before cylinder rolling in step S21 includes:

[0021] Step 211: Make the inner arc template according to the designed arc dimensions. Unless otherwise required, the chord length of the arc template at the large and small openings shall not be less than 600mm; when the diameter of the cylinder section is >4500mm, the chord length of the arc template at the large and small openings shall not be less than 800mm.

[0022] Step 212: Inspect the surface quality of the steel plate and remove foreign objects to ensure that the cutting slag on the cutting edge is clean.

[0023] Step 213: Verify the section number and related markings to ensure the correct selection of the arc template;

[0024] Step 214: Control the circumference tolerance of a single section by strictly controlling the cutting dimensions of the steel plate;

[0025] Step 215: Before the steel plate enters the rolling process, the longitudinal seam butt bevel and edges must be ground to a depth of at least 25mm to avoid affecting the welding quality.

[0026] As a further improvement to the technical solution of the present invention, in step S22, the cylindrical rolling includes:

[0027] Step S221: When feeding materials, the ends should be aligned using a middle roller in conjunction with a steel plate conveyor bed to prevent corner shifting.

[0028] Step S222: Keep the upper roller at a certain inclination, pre-bend an arc of about 200-300mm at one end, and check the ends of the large and small openings with a template. Only after it is qualified can continuous rolling be carried out; if necessary, draw 5-7 lines on the sheet.

[0029] Step S223: During the rolling process, the peeling oxide scale should be cleaned up at any time, and the forming condition should be observed. At the same time, the arc of the large and small ends should be checked at any time using the corresponding inner arc template. Local concavity and convexity should meet the specifications. A certain amount of springback should be considered after the steel plate is rolled into a circle.

[0030] Step S224: When rolling large-diameter cylindrical sections, a crane or auxiliary frame of a plate rolling machine must be used to avoid deformation of the rolled workpiece due to the weight of the steel plate. However, care should be taken not to lift the crane or auxiliary device too high, which may cause permanent deformation of the formed arc segment.

[0031] Step S225: When cutting the pre-bent cylinder section for the second time, the dimensions must be accurate, and the cut surface in the thickness direction should be perpendicular to the surface of the steel plate.

[0032] As a further improvement to the technical solution of the present invention, in step S23, the longitudinal seam welding of the cylinder includes:

[0033] Step S231: First, thoroughly clean the oil and rust within a 20-30mm range on both sides of the longitudinal seam;

[0034] Step S232: Perform pre-welding using CO2 gas shielded welding; the pre-welded seam should have uniform height and a smooth surface;

[0035] Step S233: When lifting the cylinder section off the plate rolling machine and moving it to the designated area, a special U-shaped lifting tool or chain hook should be used. During the transportation process, shaking and mutual rubbing and collision should be prevented. The contact part between the cylinder section and the ground should be flat, free of sharp objects, and rolling should be prevented. The cylinder section should be placed neatly and regularly. The operation of the electric crane should be in accordance with the operating procedures.

[0036] As a further improvement to the technical solution of the present invention, step S24, the secondary rounding of the cylinder includes:

[0037] Step S241: After the longitudinal seam welding is completed, a second rounding is performed before NDT to ensure that the weld bevel and missing material in this part are not damaged; the arc-starting plate should be removed before the rounding; the arc-starting plate is removed by air gouging and hammering is prohibited.

[0038] Step S242: Secondary rounding is performed using a three-roll plate rolling machine. After rounding, the arc of the cylinder section should transition naturally and be smooth and uniform. In particular, the local unevenness E value at the longitudinal seam should be <(0.1t+1)mm.

[0039] Step S243: After rounding, repair, patch, and grind the surface damage caused during the rolling process. The cylinder section markings after rounding should still be clearly identifiable; otherwise, they should be rewritten.

[0040] As a further improvement to the technical solution of the present invention, in step S31, the requirements before assembling the cylindrical assembly include:

[0041] Step S311: Use a CNC cutting machine to ensure the thinning accuracy and surface flatness;

[0042] Step S312: Strictly control the misalignment: Adjust the position of the single section using the hydraulic roller frame. If the misalignment exceeds the specification requirements, use a hydraulic jack to adjust the misalignment to meet the requirements, and then spot weld it in place.

[0043] As a further improvement to the technical solution of the present invention, in step S32, the construction process of the cylindrical assembly includes:

[0044] Step S321: After the individual segments are manufactured, they are hoisted onto the roller frame for assembly, following the sequence of segment rolling back into a circle → inspection → assembly → circumferential welding → precision inspection;

[0045] Step S322: Align the outer edges of the butt welds on the cylinder wall and the web plate. When the thickness difference between the butt plates is greater than 5mm, the thickness change section needs to be transitioned by cutting the thick plate to the same thickness as the thin plate. The transition slope is 1:4 and the cutting length is 4 times the thickness difference. When the thickness difference is less than or equal to 5mm, no cutting is required.

[0046] As a further improvement to the technical solution of the present invention, in step S33, the non-destructive testing of the cylindrical weld includes: the steel plate splice seam is a double-sided bevel weld, the weld grade is Class 1, requiring full penetration, and 100% UT testing is required 24 hours after welding. Only after passing the test can the next process be carried out; the rolled butt longitudinal seam is a double-sided bevel weld, the weld grade is Class 1, requiring full penetration, and 100% UT and 100% MT testing are required 24 hours after welding.

[0047] As a further improvement to the technical solution of the present invention, in step S34, the rolled steel pipe should meet the requirements of the specification, and measurements should be taken strictly at 1m intervals along the pipeline. The butt welding between steel pipes should meet the following requirements:

[0048] (1) Within any 3.0m range of the steel pipe, there shall not be three or more circumferential welds;

[0049] (2) The warping deviation of the longitudinal steel plates of the cylinder section joint shall not exceed 3mm within a range of 600mm; the misalignment deviation of the cylinder section joint shall be 1 / 10 of the plate thickness and shall not exceed 3mm.

[0050] (3) The minimum longitudinal weld spacing of the cylinder section assembly is 500mm.

[0051] In step S35, each section of the cylinder is rolled from 2 to 4 plates according to the cylinder diameter and the design requirements for plate thickness at different locations. After the cylinder is rolled and welded, it should be rounded back, and the local unevenness and overall dimensions should be properly handled to meet the following requirements:

[0052] (1) Straightness of cylinder: ≤10mm;

[0053] (2) The ellipticity of the upper opening, D1, is ≤3mm;

[0054] (3) Ellipticity at other locations: ±1% of diameter, and not greater than 6mm;

[0055] (4) End face perpendicularity: less than 2mm

[0056] Compared with the prior art, the invention has the following beneficial effects:

[0057] This invention first involves cutting the sheet metal into the required roll size, then rolling it, welding the longitudinal seams, and finally rounding it. After each section of the cylinder is processed, it is assembled and joined together. The butt welds for different plate thicknesses use a transition bevel welding method. After the assembly is completed, flaw detection and dimensional inspection are performed. This invention solves the manufacturing problem of large-diameter steel cylinders of varying thicknesses, reduces construction difficulty, and improves manufacturing efficiency. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the cylindrical rolling process according to an embodiment of the present invention;

[0059] Figure 2 This is a schematic diagram of longitudinal seam welding according to an embodiment of the present invention;

[0060] Figure 3 This is a schematic diagram of the circle alignment and return process according to an embodiment of the present invention;

[0061] Figure 4 This is a schematic diagram of the steel cylinder splicing according to an embodiment of the present invention;

[0062] Figure 5 This is a schematic diagram of the steel cylinder measurement arrangement according to an embodiment of the present invention;

[0063] Figure 6 This is a flowchart of the cylinder manufacturing process according to an embodiment of the present invention. Detailed Implementation

[0064] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0065] It should be noted that all directional indicators (such as up, down, left, right, front, back, upper end, lower end, top, bottom, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0066] In this invention, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0067] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination should be considered non-existent and not within the scope of protection claimed by this invention.

[0068] The present invention will be further described in detail below with reference to the accompanying drawings.

[0069] Reference Figures 1 to 6 This invention provides a method for processing steel cylinders of different plate thicknesses, enabling the rolling of large-diameter steel cylinders of different thicknesses and the butt jointing of steel cylinders of different plate thicknesses. The method includes the following steps:

[0070] 1. Parts blanking and machining:

[0071] For parts cut using gas cutting or plasma cutting, random sampling inspection is conducted on-site each time parts are cut. Parts are measured and inspected using a steel ruler or tape measure. The permissible deviations for this type of cut parts are as follows:

[0072] Table 1. Allowable Deviations for Gas Cutting (Unit: mm)

[0073]

[0074] 2. Cylindrical tube rolling and rewinding process:

[0075] 2.1 Preparations before rolling:

[0076] (1) Make an inner arc template according to the designed arc dimensions (an outer arc template should be made if necessary). Unless otherwise required, the chord length of the arc template at the large and small ends shall not be less than 600 mm. When the diameter of the cylinder section is >4500 mm, the chord length of the arc template at the large and small ends shall not be less than 800 mm.

[0077] (2) Check the surface quality of the steel plate and clean up foreign objects, especially whether the cutting slag on the cutting edge is cleaned up;

[0078] (3) Check the section number and related markings to facilitate the correct selection of the arc template;

[0079] (4) Control the circumference tolerance of a single section by strictly controlling the cutting dimensions of the steel plate;

[0080] (5) Before the steel plate is rolled, the longitudinal seam bevel and the edge must be ground by more than 25mm to avoid affecting the welding quality.

[0081] 2.2 Rolling:

[0082] (1) When feeding materials, the ends should be aligned using a middle roller in conjunction with a steel plate conveyor bed to prevent corner shifting;

[0083] (2) Hold the upper roller at a certain inclination, pre-bend the end of the roller to a required arc of about 200-300mm, and check the ends of the rollers with a template. Only after it passes the test can continuous rolling be carried out. If necessary, draw 5-7 lines on the sheet material;

[0084] (3) During the rolling process, the peeled oxide scale should be cleaned up at any time, and the forming condition should be observed. At the same time, the arc of the large and small ends should be checked at any time using the corresponding inner arc template. Local concavity and convexity should meet the specifications. A certain amount of springback should be considered after the steel plate is rolled into a circle.

[0085] (4) When rolling large-diameter cylindrical sections, a crane or auxiliary frame of a plate rolling machine must be used to avoid deformation of the rolled workpiece due to the weight of the steel plate. However, care should be taken not to lift the crane or auxiliary device too high, which may cause permanent deformation of the formed arc section.

[0086] (5) For cylinder sections with pre-bent heads, accurate dimensions are required during secondary cutting, and the cut surface in the thickness direction should be perpendicular to the steel plate surface. (Refer to...) Figure 1 .

[0087] 2.3 Longitudinal seam welding:

[0088] (1) First, thoroughly clean the oil and rust within a range of 20-30mm on both sides of the longitudinal seam;

[0089] (2) Pre-welding is performed using CO2 gas shielded welding. The pre-welded joints must have uniform height and a smooth surface.

[0090] (3) When lifting the cylinder sections off the plate rolling machine and moving them to the designated area, a dedicated U-shaped lifting device or chain hook should be used. During transport, swaying and mutual rubbing / collision should be prevented. The contact area between the cylinder sections and the ground should be flat, free of sharp objects, and rolling should be prevented. The sections should be neatly and regularly arranged. Electric crane operation should follow the operating procedures. (Refer to...) Figure 2 .

[0091] 2.4 Secondary circle alignment:

[0092] (1) After the longitudinal seam welding is completed, a second rounding should be performed before NDT to ensure that the weld bevel and missing material in this part are not damaged; the arc-starting plate should be removed before the rounding. The arc-starting plate should be removed by air gouging and hammering is prohibited.

[0093] (2) The secondary rounding is performed using a three-roll plate rolling machine. After rounding, the arc of the cylinder section should transition naturally and be smooth and uniform. In particular, the local unevenness (edges) at the longitudinal seam should meet the following requirements (if the design specification has additional requirements, follow the design specification): The E value should be < (0.1t+1) mm (see... Figure 2 ).

[0094] (3) After rounding, repair, patch, and grind any surface damage caused during the rolling process. The markings on the cylinder sections should still be clearly legible after rounding; otherwise, they should be rewritten. (Refer to...) Figure 3 .

[0095] 3. Cylindrical pipe section assembly process:

[0096] 3.1 Requirements before assembling the steel cylinder:

[0097] (1) Use a CNC cutting machine to ensure the precision of thinning and the smoothness of the surface;

[0098] (2) Strictly control the misalignment: Adjust the position of the single section with the hydraulic roller frame. If the misalignment exceeds the specification requirements, use the hydraulic jack to handle the misalignment until it meets the requirements, and then spot weld it in place.

[0099] 3.2 Assembly and construction process:

[0100] After a single segment is manufactured, it is hoisted onto a roller frame for assembly, following the sequence of segment rolling back into a circle → inspection → assembly → circumferential welding → precision inspection.

[0101] For butt welds on the cylinder wall and web, the outer edges should be aligned. When the thickness difference between the butt plates is greater than 5mm, a thickness transition is required at the thickness change section. The thicker plate should be beveled to the same thickness as the thinner plate, with a transition slope of 1:4 and a beveling length of 4 times the thickness difference. See the detailed welding drawings for butt welds in this booklet. When the thickness difference is less than or equal to 5mm, no beveling is required. (Refer to...) Figure 4 .

[0102] 3.3 Non-destructive testing of welds:

[0103] The steel plate splices are double-sided bevel welds, with a weld grade of Class 1, requiring full penetration. A 100% UT (Ultrasound Testing) inspection is required 24 hours after welding. Only after passing the inspection can the next process proceed. The rolled butt joints are double-sided bevel welds, with a weld grade of Class 1, requiring full penetration. Both 100% UT and 100% MT (Medium-to-Medium Testing) inspections are required 24 hours after welding. The UT inspection standard follows the first amendment to the industry standard "Non-destructive Testing of Pressure Equipment Part 3: Ultrasonic Testing" (NB / T47013.3-2015 / XG1-2018), with an acceptance level of Class I.

[0104] 3.4 Precision Control:

[0105] Rolled steel pipes shall conform to the requirements of SY / Y 10002-2000 standard, and measurements shall be taken strictly at 1m intervals along the pipeline. Butt welding between steel pipes shall meet the following requirements:

[0106] (1) Within any 3.0m range of the steel pipe, there shall not be three or more circumferential welds.

[0107] (2) The warping deviation of the longitudinal steel plates of the cylinder section joint shall not exceed 3mm within a range of 600mm. The misalignment deviation of the cylinder section joint shall be 1 / 10 of the plate thickness and shall not exceed 3mm.

[0108] (3) The minimum longitudinal weld spacing of the cylinder section assembly is 500mm.

[0109] 3.5 Dimensional Measurement:

[0110] Depending on the cylinder diameter and plate thickness requirements at different locations, each cylinder section can be made from 2 to 4 rolled plates. After rolling and welding, the cylinder should be rounded back, and local unevenness (especially at the longitudinal seams of the plates) and overall dimensions should be properly handled to meet the following requirements:

[0111] (1) Straightness of cylinder: ≤10mm.

[0112] (2) Ovality of the upper opening D1 (connected to the flange end): ≤3mm (difference between mutually perpendicular outer diameters);

[0113] (3) Ellipticity in other positions: ±1% of diameter, and not greater than 6mm (difference between mutually perpendicular diameters).

[0114] (4) End face perpendicularity: less than 2mm;

[0115] (5) Perimeter deviation: The perimeter at any position of the pipe section should be less than 0.1% or 10 mm of the nominal perimeter, whichever is smaller. (Refer to...) Figure 5 .

[0116] Compared with existing technologies, the present invention has the following advantages:

[0117] This invention first involves cutting the sheet metal into the required roll size, then rolling it, welding the longitudinal seams, and finally rounding it. After each section of the cylinder is processed, it is assembled and joined together. The butt welds for different plate thicknesses use a transition bevel welding method. After the assembly is completed, flaw detection and dimensional inspection are performed. This invention solves the manufacturing problem of large-diameter steel cylinders of varying thicknesses, reduces construction difficulty, and improves manufacturing efficiency.

[0118] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for processing steel cylinders of different plate thicknesses, characterized in that, Includes the following steps: Step S1, Parts cutting and processing: Parts are cut by gas cutting or plasma cutting, and random sampling is carried out on site each time parts are cut; Step S2, the cylindrical tube rolling and rewinding processes, respectively include: Step S21: Preparations before cylinder rolling; Step S22: Cylindrical rolling; Step S23: Welding the longitudinal seam of the cylinder; Step S24: Secondary rounding of the cylinder; Step S3, Assembly of cylindrical pipe fittings, including: Step S31, Pre-assembly requirements for cylindrical components; Step S32, Cylindrical assembly construction process; Step S33: Non-destructive testing of cylindrical welds; Step S34: Cylinder precision control; Step S35: Measure the cylinder dimensions; Step S4: The cylinder is marked with a spray mark. After the cylinder is inspected by the user or undergoes final inspection, it is put into storage. In step S32, the construction process for the cylindrical assembly includes: Step S321: After the individual segments are manufactured, they are hoisted onto the roller frame for assembly, following the sequence of segment rolling back into a circle → inspection → assembly → circumferential welding → precision inspection; Step S322: Align the outer edges of the butt welds on the cylinder wall and the butt welds on the web. When the thickness difference between the butt plates is greater than 5mm, the thickness change section needs to be transitioned by cutting the thick plate to the same thickness as the thin plate. The transition slope is 1:4 and the cutting length is 4 times the thickness difference. When the thickness difference is less than or equal to 5mm, no cutting is required. In step S33, the non-destructive testing of the cylindrical weld includes: the steel plate splice seam is a double-sided bevel weld, the weld grade is 1, full penetration is required, and 100% UT test is required 24 hours after welding. Only after passing the test can the next process be carried out; the rolled butt longitudinal seam is a double-sided bevel weld, the weld grade is 1, full penetration is required, and 100% UT and 100% MT tests are required 24 hours after welding. In step S34, the rolled steel pipe should meet the requirements of the specification, and measurements should be taken strictly at 1m intervals along the pipeline. The butt welding between steel pipes should meet the following requirements: (1) Within any 3.0m range of the steel pipe, there shall not be three or more circumferential welds; (2) The warping deviation of the longitudinal steel plates of the cylinder section joint shall not exceed 3mm within a range of 600mm; the misalignment deviation of the cylinder section joint shall be 1 / 10 of the plate thickness and shall not exceed 3mm. (3) The minimum longitudinal weld spacing of the cylinder section assembly is 500mm; In step S35, each section of the cylinder is rolled from 2 to 4 sheets of steel, according to the cylinder diameter and the design requirements for plate thickness at different locations. After the cylinder is rolled and welded, it should be rounded back, and the local unevenness and overall dimensions should be properly handled to meet the following requirements: (1) Straightness of cylinder: ≤10mm; (2) The ellipticity of the upper opening, D1, is ≤3mm; (3) Ellipticity at other locations: ±1% of diameter, and not greater than 6mm; (4) Perpendicularity of end face: less than 2mm.

2. The method for processing steel cylinders of different plate thicknesses according to claim 1, characterized in that: In step S1, the parts are measured and inspected using a steel ruler or tape measure. The allowable deviations for this type of cut parts are: the allowable range for the width and length of the parts is ±1.5mm; the cut flatness is 0.05-2.0mm; the cut depth is no more than 0.3mm; and the depth of the local notch is no more than 1.0mm.

3. The method for processing steel cylinders of different plate thicknesses according to claim 1, characterized in that: In step S21, the preparatory work before cylinder rolling includes: Step 211: Make the inner arc template according to the designed arc dimensions. Unless otherwise required, the chord length of the arc template at the large and small openings shall not be less than 600mm; when the diameter of the cylinder section is >4500mm, the chord length of the arc template at the large and small openings shall not be less than 800mm. Step 212: Inspect the surface quality of the steel plate and remove foreign objects to ensure that the cutting slag on the cutting edge is clean. Step 213: Verify the section number and related markings to ensure the correct selection of the arc template; Step 214: Control the circumference tolerance of a single section by strictly controlling the cutting dimensions of the steel plate; Step 215: Before the steel plate enters the rolling process, the longitudinal seam butt bevel and edges must be ground to a depth of at least 25mm to avoid affecting the welding quality.

4. The method for processing steel cylinders of different plate thicknesses according to claim 1, characterized in that: In step S22, the cylindrical rolling includes: Step S221: When feeding materials, the ends should be aligned using a middle roller in conjunction with a steel plate conveyor bed to prevent corner shifting. Step S222: Keep the upper roller at a certain inclination, pre-bend an arc of about 200-300mm at one end, and check the ends of the large and small openings with a template. Only after it is qualified can continuous rolling be carried out; if necessary, draw 5-7 lines on the sheet. Step S223: During the rolling process, the peeling oxide scale should be cleaned up at any time, and the forming condition should be observed. At the same time, the arc of the large and small ends should be checked at any time using the corresponding inner arc template. Local concavity and convexity should meet the specifications. A certain amount of springback should be considered after the steel plate is rolled into a circle. Step S224: When rolling large-diameter cylindrical sections, a crane or auxiliary frame of a plate rolling machine must be used to avoid deformation of the rolled workpiece due to the weight of the steel plate. However, care should be taken not to lift the crane or auxiliary device too high, which may cause permanent deformation of the formed arc segment. Step S225: For the pre-bent cylinder section, the dimensions must be accurate during the second cutting, and the cutting surface in the thickness direction should be perpendicular to the surface of the steel plate.

5. The method for processing steel cylinders of different plate thicknesses according to claim 1, characterized in that: In step S23, the longitudinal seam welding of the cylinder includes: Step S231: First, thoroughly clean the oil and rust within a 20-30mm range on both sides of the longitudinal seam; Step S232: Perform pre-welding using CO2 gas shielded welding; the pre-welded seam should have uniform height and a smooth surface; Step S233: When lifting the cylinder section off the plate rolling machine and moving it to the designated area, a special U-shaped lifting tool or chain hook should be used. During the transportation process, shaking and mutual rubbing and collision should be prevented. The contact part between the cylinder section and the ground should be flat, free of sharp objects, and rolling should be prevented. The cylinder section should be placed neatly and regularly. The operation of the electric crane should be in accordance with the operating procedures.

6. The method for processing steel cylinders of different plate thicknesses according to claim 1, characterized in that: In step S24, the secondary rounding of the cylinder includes: Step S241: After the longitudinal seam welding is completed, a second rounding is performed before NDT to ensure that the weld bevel and missing material in this part are not damaged; the arc-starting plate should be removed before the rounding; the arc-starting plate is removed by air gouging and hammering is prohibited. Step S242: Secondary rounding is performed using a three-roll plate rolling machine. After rounding, the arc of the cylinder section should transition naturally and be smooth and uniform. The local unevenness E value at the longitudinal seam should be <(0.1t+1)mm. Step S243: After rounding, repair, patch, and grind the surface damage caused during the rolling process. The cylinder section markings after rounding should still be clearly identifiable; otherwise, they should be rewritten.

7. The method for processing steel cylinders of different plate thicknesses according to claim 1, characterized in that: In step S31, the requirements for the cylindrical assembly include: Step S311: Use a CNC cutting machine to ensure the thinning accuracy and surface flatness; Step S312: Strictly control the misalignment: Adjust the position of the single section using the hydraulic roller frame. If the misalignment exceeds the specification requirements, use a hydraulic jack to adjust the misalignment to meet the requirements, and then spot weld it in place.

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