A method for manufacturing a thick cold-formed high-strength steel curved surface structure

Abstract

The present invention relates to the field of high-strength steel structures. The present invention provides a method for manufacturing a large-thickness cold-formed high-strength steel curved surface structure, including step one, a preset block method of the curved surface structure: according to the curved surface structure specifications to be prepared, the curved surface structure is decomposed into spherical blocks and curved surface transition ring blocks; step two, cold forming: a steel plate of a required size is point-pressed by a press to prepare the required spherical blocks and curved surface transition ring blocks; step three, tooling production; step four, heat treatment; step five, assembly welding; through the large-thickness cold-formed high-strength steel curved surface structure manufacturing method described in the present invention, the performance level of the large-thickness high-strength steel curved surface structure can be improved, and the stability of the structure and the safety during service can be guaranteed; thereby, it is beneficial to improve the mass production efficiency of large-thickness high-strength steel curved surface structures, reduce the manufacturing cost of curved surface structures, expand the scope of application of the manufacturing method, and meet the manufacturing of high-strength steel structures of different specifications.

Description

Technical Field

[0001] The invention relates to the field of high-strength steel structures, and in particular to a method for manufacturing a thick cold-formed high-strength steel curved surface structure. Background Art

[0002] Key parts such as nuclear power containment heads, pressure vessel heads, and deep-sea equipment pressure-resistant structures all use spherical structures, and curved transition rings are generally used at the connection between the spherical structure and its shell. These curved structures not only play a sealing role during service, but also bear huge pressure. In recent years, with the large-scale and complex service environment of various types of equipment in my country, the thickness of curved structures has become larger and larger, and the strength grade of the materials used has become higher and higher, which has put forward an urgent demand for high-quality and low-cost manufacturing. The main forming methods of curved structures are casting, forging, steel plate cold forming, steel plate hot die forming, steel plate welding + hot forming, etc. At present, for high-strength steel curved structures, steel plate cold forming is still the most mature and economical manufacturing method.

[0003] Due to the Bauschinger effect, the yield strength of the compressive surface of the steel plate after cold forming will be lower than that before forming, and the yield strength of the tensile surface will be higher than that before forming, and even fail to meet the index requirements specified in the standard; at the same time, due to the work hardening during the forming process, the elongation after fracture will also be reduced to a certain extent. This affects the service safety of high-strength steel curved surface structures. It is known that heat treatment is an effective means to solve this problem. The cold forming + heat treatment method for special-shaped structure manufacturing is also widely used in the manufacturing field: Patent CN201710715115.2 "A heat treatment process for micro-deformation control of the forming position of curved special-shaped parts", the formed special-shaped parts are placed in a vacuum furnace for temperature treatment, and the temperature is raised to 500-600℃, 750-850℃, 950-1000℃, 1100-1200℃ in a step-by-step manner. After a certain period of heat preservation, it is cooled in a protective gas environment and then subjected to high-temperature tempering, deep-cold treatment, hardness-controlled tempering, etc.; Patent CN201410337661.3 "Cold-formed head heat treatment method" , different heat treatment methods are selected according to the deformation rate. When the deformation rate is small, stress relief annealing is used. When the deformation rate is large, 890-920℃ normalizing treatment + natural cooling or forced cooling is used; Patent CN202311718666.6 "A 9Ni steel LNG tank head flap molding method" divides the head into flaps, uses a special mold to perform warm pressing molding at 520℃±15℃, and then cools in the air; Patent CN202311476779.X "A processing method for a large stainless steel thick-walled spherical tank head" uses a mold to cold-form the fan-shaped flat plate into spherical melon slices, and presses the spherical surface The melon slices are welded, then heat treated at 400℃±15℃, and then solution heat treated at 1060℃, and cooled in a cooling water pool; Patent CN201610278113.7 "A heat treatment process for hot-formed heads of large-diameter thick-walled chromium-molybdenum steel" normalizes the hot-formed heads at 940℃, tempers at 710±20℃, and relieves stress at 670±20℃; Patent CN202310454820.7 "A heat treatment method for restoring the performance of high-toughness container steel plates after hot forming" uses two quenching + tempering heat treatment processes to perform performance recovery heat treatment on high-toughness container steel plates after hot forming. The above-mentioned cold-formed structure heat treatment processes are relatively complex, with high requirements for equipment and construction, and the accuracy of the components cannot be controlled during the cooling process, which is not suitable for the manufacture of high-strength steel components with large thickness and high precision.

[0004] In view of this, it is necessary to carry out research on the manufacturing process design of large-thickness cold-formed high-strength steel curved surface structural parts to break through the limitations of existing manufacturing methods and meet the needs of equipment construction of large-thickness, high-strength steel curved surface structures. Summary of the invention

[0005] In view of this, the present invention aims to propose a method for manufacturing large-thickness cold-formed high-strength steel curved surface structures, so as to solve the problems existing in the prior art that the performance of cold-formed curved surface structures is uneven along the reverse direction of the plate surface and the reverse direction of the thickness, and the difficulty in controlling the structural dimensional accuracy; thereby effectively solving the problems that the performance of cold-formed curved surface structures is uneven along the reverse direction of the plate surface and the reverse direction of the thickness, and the difficulty in controlling the structural dimensional accuracy, providing technical support for the safe service of pressure-resistant structures, and improving the performance level of large-thickness high-strength steel curved surface structures, ensuring the stability of the structure and the safety during service; thereby helping to improve the mass production efficiency of large-thickness high-strength steel curved surface structures, reduce the manufacturing cost of curved surface structures, expand the scope of application of the manufacturing method, and meet the manufacturing of high-strength steel structures of different specifications.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] The present invention relates to a method for manufacturing a thick cold-formed high-strength steel curved surface structure, the method comprising the following steps:

[0008] Step 1: Preset the block method of the curved surface structure: according to the specifications of the curved surface structure to be prepared, decompose the curved surface structure into spherical blocks and curved surface transition ring blocks;

[0009] Step 2, cold forming: using a press machine to point press the steel plate of the required size to prepare the required spherical blocks and curved transition ring blocks;

[0010] Step 3: Tooling production: Produce anti-deformation support tooling for the curved surface structure, and fix each block in the curved surface structure on the support tooling to form an assembly;

[0011] Step 4, heat treatment: put the assembly into a heat treatment furnace with a first preset temperature below T1°C, then control the heat treatment furnace to heat up to a second preset temperature T2°C at a heating rate V1, keep the temperature for a preset time tmin, and then quickly take it out of the furnace and cool it with water;

[0012] Step 5: Assembly welding: The prepared spherical blocks and curved transition ring blocks are fixed on the supporting fixture according to relative positions, and the spherical blocks and curved transition ring blocks are welded in both longitudinal and transverse directions using equal-strength welding materials and matching welding processes.

[0013] Furthermore, at least one spherical surface block and one curved surface transition ring block are provided.

[0014] Further, step one includes:

[0015] Step S11: according to the curved surface structure specifications to be prepared, decomposing the curved surface structure into spherical blocks and curved surface transition ring blocks;

[0016] Step S12: Obtain any one or more dimension factors of the size of the curved surface structure to be prepared, the size of the melting furnace, and the size of the press;

[0017] Step S13: Calculate based on the obtained different types of size data to determine the size and quantity of spherical chunking and curved transition ring chunking nesting.

[0018] Further, the spherical tiles include circular spherical tiles and / or fan spherical tiles.

[0019] Further, step two includes:

[0020] Step S21: Select steel plates corresponding to the specifications of each block according to the size and number of different spherical blocks and curved surface transition ring blocks;

[0021] Step S22: After point-pressing molding is performed using a press according to the strength, thickness and structural dimensions of the selected steel plate, each spherical block and curved transition ring block is prepared.

[0022] Further, in step S22, the point pressing molding of each block includes n pass point pressing processing, n is a positive integer.

[0023] Furthermore, in step S22, after each point pressing process, the surface radius of the block after the current point pressing process needs to be measured through a sample box, and when the measurement result meets the requirements, the next block is subjected to point pressing forming process.

[0024] Further, step three includes:

[0025] Step S31: Use steel to make a supporting tool with interlaced weft and weft in combination with the size of each block in the curved surface structure;

[0026] Step S32: Each piece of the curved surface structure is fixedly arranged on the tooling in a spot welding manner.

[0027] Further, in step 4, the value range of the heating speed V1 is 70°C / h-100°C / h.

[0028] Further, in step 4, the value range of T2 is 580-620.

[0029] Compared with the prior art, a high-thick cold forming high-strength steel curved surface structure manufacturing method described in the present invention has the following beneficial effects:

[0030] Through the setting of the method, the problems of uneven performance of cold-formed curved surface structural parts along the reverse direction of the plate surface and the reverse direction of the thickness, and the difficulty in controlling the structural dimensional accuracy can be effectively solved, providing technical support for the safe service of pressure-resistant structures, and improving the performance level of large-thickness high-strength steel curved surface structures, ensuring the stability of the structure and safety during service; and thus being conducive to improving the mass production efficiency of large-thickness high-strength steel curved surface structures, reducing the manufacturing cost of curved surface structures, expanding the scope of application of the manufacturing method, and being able to meet the manufacturing of high-strength steel structures of different specifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which constitute part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention. In the accompanying drawings:

[0032] Figure 1 It is a first viewing angle diagram of the curved surface structure of high-strength steel;

[0033] Figure 2 It is a schematic diagram of the second viewing angle of high-strength steel curved surface structure;

[0034] Figure 3 It is a schematic diagram of the specific structure of the welding bevel position of the ring weld (t is the thickness of the steel plate, unit is mm in the figure). DETAILED DESCRIPTION

[0035] The inventive concepts of the present disclosure will be described below using terms commonly used by those skilled in the art to convey the essence of their work to other persons skilled in the art. However, these inventive concepts can be embodied in many different forms and should not be considered limited to the embodiments described herein.

[0036] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0037] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0038] In order to solve the problems in the prior art that the performance of cold-formed curved surface structural parts is uneven along the reverse direction of the plate surface and the thickness, and that the structural dimension precision control is difficult; this embodiment proposes a method for manufacturing a large-thickness cold-formed high-strength steel curved surface structure, which is suitable for the process design and manufacturing of nuclear power and petrochemical pressure vessel spherical heads, deep-sea equipment curved surface structures, etc. The method comprises the following steps:

[0039] Step 1. Preset the block method of the curved surface structure: according to the specifications of the curved surface structure to be prepared, decompose the curved surface structure into spherical blocks and curved surface transition ring blocks; wherein, at least one spherical block and one curved surface transition ring block are set, and the specific number of each block needs to be determined in combination with the size of each curved surface structure, the influence of any one or more factors of the smelting furnace and the press size.

[0040] Step 2, cold forming: using a press machine to point press the steel plate of the required size to prepare the required spherical blocks and curved transition ring blocks;

[0041] Step 3: Tooling production: Produce anti-deformation support tooling for the curved surface structure, and fix each block in the curved surface structure on the support tooling to form an assembly;

[0042] Step 4, heat treatment: Place the assembly into a heat treatment furnace with a first preset temperature below T1°C, then control the heat treatment furnace to heat up to a second preset temperature T2°C at a heating rate V1, and keep it at that temperature for a preset time tmin, then quickly take it out of the furnace and cool it in water.

[0043] Step 5: Assembly welding: The prepared spherical blocks and curved transition ring blocks are fixed on the supporting fixture according to relative positions, and the spherical blocks and curved transition ring blocks are welded in both longitudinal and transverse directions using equal-strength welding materials and matching welding processes.

[0044] Through the setting of the method, the problems of uneven performance of cold-formed curved surface structural parts along the reverse direction of the plate surface and the reverse direction of the thickness, and the difficulty in controlling the structural dimensional accuracy can be effectively solved, providing technical support for the safe service of pressure-resistant structures, and improving the performance level of large-thickness high-strength steel curved surface structures, ensuring the stability of the structure and safety during service; and thus being conducive to improving the mass production efficiency of large-thickness high-strength steel curved surface structures, reducing the manufacturing cost of curved surface structures, expanding the scope of application of the manufacturing method, and being able to meet the manufacturing of high-strength steel structures of different specifications.

[0045] Step one includes:

[0046] Step S11: according to the curved surface structure specifications to be prepared, decomposing the curved surface structure into spherical blocks and curved surface transition ring blocks;

[0047] Step S12: Obtain any one or more dimension factors of the size of the curved surface structure to be prepared, the size of the melting furnace, and the size of the press;

[0048] Step S13: Calculate based on the obtained different types of size data to determine the size and quantity of spherical chunking and curved transition ring chunking nesting.

[0049] Wherein, in step S13, the spherical blocks include circular spherical blocks and / or sector-shaped spherical blocks. Preferably, when the spherical blocks include circular spherical blocks and sector-shaped spherical blocks, the number of sector-shaped spherical blocks and curved surface transition ring blocks are both N, and N is an even number; the welds of the N sector-shaped spherical blocks are uniformly distributed along the circumference with the center O of the circular spherical block as the center and arranged outside the circular spherical blocks; the N curved surface transition ring blocks are uniformly distributed along the circumference with the center O of the circular spherical block as the center and arranged outside the sector-shaped spherical blocks; and the welds of the N curved surface transition ring blocks are respectively arranged at the positions of the center lines of every two welds in the sector-shaped spherical blocks.

[0050] By setting the above-mentioned weld seams, the weld seams of the fan-shaped spherical blocks and the curved transition ring blocks can be symmetrically arranged, and the weld seams of the two can be evenly distributed and arranged outside the circular spherical blocks, which can effectively reduce the problems of stress concentration and welding deformation. In addition, by setting the curved surface structure blocks in a targeted manner according to the size of the curved surface structure to be prepared, the size of the smelting furnace, and the size of the press, the flexibility of the curved surface structure preparation can be effectively improved, which is conducive to improving the manufacturing efficiency of the curved surface structure and reducing the cost consumption of the curved surface structure preparation.

[0051] Step 2 includes:

[0052] Step S21: Select steel plates corresponding to the specifications of each block according to the size and quantity of the nesting materials of different spherical blocks and curved surface transition ring blocks;

[0053] Step S22: According to the strength, thickness and structural dimensions of the selected steel plate, a press machine that meets the requirements is used to perform point pressing processing to prepare the required spherical blocks and curved transition ring blocks.

[0054] Among them, in step S22, the point pressing forming of each block includes n point pressing treatments, where n is a positive integer. After each point pressing treatment, the surface radius of the block after the current point pressing treatment needs to be measured through a sample box, and when the measurement result meets the requirements, the next block is subjected to point pressing forming. Otherwise, after n point pressing treatments are performed and the block reaches a size that meets the requirements, the next block is subjected to point pressing processing.

[0055] Different from the prior art, in which the hot forming starting temperature is generally above 900°C, which can easily cause grain growth and make subsequent performance heat treatment difficult, the present application performs cold forming treatment on the steel plate at room temperature to prepare the required blocks within the curved surface structure, which can effectively prevent the steel plate from being affected by high temperature, and thus greatly ensure that the blocks within the curved surface structure have stable toughness.

[0056] Specifically, step S22 includes:

[0057] Step S221: the selected steel plates are labeled as i, 1≤i≤m, and m is a positive integer, and a press machine that meets the requirements is used to perform point pressing processing according to the strength, thickness and structural dimensions of the selected steel plates;

[0058] Step S222: let i=1;

[0059] Step S223: During the spot pressing process, a special pressing head is set on the press machine according to the selected steel plate specifications, and the selected steel plate is set between the mold and the pressing head; this is used to improve the stability and reliability of the spot pressing of the steel plate.

[0060] Step S224: the press machine performs a point pressing process on the i-th steel plate;

[0061] Step S225: after one point pressing process, the sample box is used to measure the surface radius of the block after the current point pressing process;

[0062] Step S226: determine whether the measurement result meets the size requirement of the block to be prepared currently, if yes, execute step S227; if no, return to step S224;

[0063] Step S227: Let i=i+1, and determine whether i>m. If yes, execute step 3; if no, return to step S223.

[0064] Through the setting of cold forming treatment, in the process of point pressing treatment of different blocks, at least one point pressing treatment is performed, and the blocks after each point pressing treatment are tested through a sample box, which can effectively improve the deformation control accuracy during the cold forming process of different blocks, improve the cold forming efficiency of different blocks, and reduce the processing error during the cold forming process of different blocks. It is conducive to improving the mass production of large-thickness high-strength rigid curved surface structures, and can greatly improve the economic benefits of curved surface structure manufacturing. It can also be applied to the manufacture of cold-formed high-strength steel structures of any thickness and size.

[0065] Step three includes:

[0066] Step S31: according to the size of each block in the curved structure, a support tooling with interlaced longitude and latitude is made by using steel;

[0067] Step S32: fix each block in the curved surface structure on the tooling by spot welding.

[0068] By using steel sections to set up supporting tooling, the quality of the tooling can be reduced as much as possible while ensuring the structural strength of the tooling, and the cost of the tooling can be reduced, thereby better supporting the blocks for heat treatment and preventing the blocks from deforming during the heat treatment process. It is also beneficial to support the assembly welding of each block in step five.

[0069] In step 4, T1 is set to be less than 300, the temperature rise rate V1 is set to be in the range of 70°C / h-100°C / h, and T2 is set to be in the range of 580-620. The value range of t is 3T-4T, where T is the thickness of the steel plate and the unit of T is mm.

[0070] Since the internal dislocations of the steel plate undergo directional movement after cold forming, and density multiplication and dislocation entanglement occur, the yield strength and elongation of the steel change significantly, especially on the two sides of the surface with the largest deformation. Therefore, the cold-formed structural parts are heat treated at the second preset temperature T2℃, i.e., 580℃-620℃, which can eliminate the dislocation entanglement and dislocation accumulation generated during the cold forming process, reduce the dislocation density, and release the deformation stress. At the same time, this temperature is lower than the recrystallization temperature of high-strength steel, so it will not cause changes in grain size. In addition, since the heating rate is too fast, the temperature difference between the surface and the core of the workpiece is too large, the heating is uneven, and internal thermal stress is easily generated. If it is too slow, it will cause energy waste and increase the production cycle. The present invention sets the value range of the heating rate V1 to 70℃ / h-100℃ / h, which is conducive to ensuring uniform heating of each block, avoiding the generation of internal thermal stress, and can reduce the waste of energy in the process of manufacturing curved structures, shorten the production cycle of curved structures, and reduce the cost of curved structure production. In addition, since the holding time is too short, the dislocations generated by cold forming are difficult to fully eliminate, resulting in incomplete performance recovery; too long a time causes energy waste and increases in production cycles. The present invention sets the holding time t to 3T-4T minutes, which can effectively and fully eliminate the dislocations generated by cold forming, and is conducive to accurately controlling the holding time to prevent energy waste caused by too long a time. In addition, since the cooling rate seriously affects the toughness of the steel plate, the faster the cooling rate, the closer the impact toughness of the steel plate, especially the toughness of the core, is to the new level before forming. Therefore, the present invention adopts water cooling. At the same time, in order to prevent deformation caused by rapid cooling, anti-deformation support tooling is fixed on the structural parts before heat treatment. It is conducive to ensuring the toughness of the steel plate to a great extent.

[0071] Step five includes:

[0072] Step S51: fixing the prepared spherical blocks and curved transition ring blocks on a supporting fixture according to relative positions;

[0073] Step S52: using equal-strength welding materials and matching welding processes to complete longitudinal seam welding of the spherical surface blocks and the curved surface transition ring blocks at the vertical welding position;

[0074] Step S53: completing the girth weld of the spherical block and the curved transition ring at the horizontal welding position. The welding groove of the girth weld is a double-sided narrow U-shaped groove, which is used to reduce the welding workload when the welding conditions are met.

[0075] Since welding heat input will cause deformation of structural parts and affect subsequent assembly, the setting of anti-deformation support tooling can effectively prevent the welding deformation of curved structural parts and improve assembly accuracy. In addition, by selecting equal-strength matching welding materials for welding materials, on the one hand, it can effectively ensure the uniformity of the overall strength of the joint, and on the other hand, it can avoid problems such as large workload during low-strength matching and high welding difficulty during high-strength matching. In addition, based on the properties of large-thickness high-strength steel and equal-strength matching welding materials, its welding is more difficult than ordinary steel structures. If conventional groove forms are used, the weld filling volume is large, and the manpower and technical requirements are very high. Therefore, the groove of the curved structure in the present invention is set as a double-sided narrow U-shaped groove, which reduces the welding workload while meeting the welding conditions.

[0076] Example 1

[0077] For the hemispherical structure of deep-sea submersible with a thickness of 55 mm and an outer diameter of 3.6 mm, the material is 800 MPa grade low-alloy high-strength steel, and the structural dimensions are designed as "1 circular spherical block + 4 fan-shaped spherical blocks + 4 curved transition ring blocks". A 30-ton press is used with a special press head and a mold to perform point pressing. The maximum error of the block size after cold forming is 2.7 mm. The workpiece is fixed on the supporting fixture and loaded into the heat treatment furnace at room temperature. Then the temperature is controlled to rise to (585 ± 5) °C at (90 ± 10) °C / h, kept at (180 ± 10) min, and then cooled by water after being removed from the furnace. After removing the fixture, the maximum deformation of the workpiece is 4.5 mm. After the block assembly welding is completed, the dimensional error of the curved surface structure is still no more than 10 mm. Samples are taken from the fan-shaped spherical blocks before and after heat treatment for performance analysis, and the results are shown in Table 1. The results show that after heat treatment, the yield strength of the component recovers to the level before deformation, the yield strength at the inner surface increases, the yield strength at the outer surface decreases, and the yield strength at each position meets the index requirements; the elongation after fracture is significantly restored, which is slightly higher than that before cold forming; the impact absorption energy at -20℃ is equivalent to that before and after cold forming.

[0078] Table 1 Mechanical performance test results of high-strength curved surface components in Example 1

[0079]

[0080] Example 2

[0081] For the hemispherical structure of deep-sea equipment with a thickness of 75mm and an outer diameter of 5.2mm, the material is 800MPa-grade low-alloy high-strength steel. According to the structural dimensions, it is designed as "2 semicircular spherical blocks + 6 fan-shaped spherical blocks + 6 curved transition ring blocks". A 30-ton press is used with a special press head and a mold to perform point pressing. After cold forming, the block size error does not exceed 3.3mm. The workpiece is fixed on the supporting fixture and placed in the heat treatment furnace. It is loaded into the heat treatment furnace at a temperature below 300℃, and then the temperature is controlled to rise to (610±10)℃ at (80±10)℃ / h, and the temperature is kept at (240±10)min, and then the furnace is water-cooled. After removing the fixture, the maximum deformation of the workpiece does not exceed 5.0mm. After the block assembly welding is completed, the size error of the curved structure is still no more than 10mm. Samples are taken from the curved transition ring blocks before and after heat treatment for performance analysis, and the results are shown in Table 2. The results show that after heat treatment, the yield strength of the component recovers to the level before deformation, the yield strength of the inner surface and inner T / 4 position increases, the yield strength of the outer surface and outer T / 4 position decreases, and the yield strength at each position meets the index requirements; the elongation after fracture is significantly restored, which is slightly higher than that before cold forming; the impact absorption energy at -20℃ is equivalent to that before and after cold forming.

[0082] Table 2 Results of mechanical properties of high-strength curved surface components in Example 2

[0083]

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a thick cold-formed high-strength steel curved surface structure, characterized in that: The method comprises the following steps: Step 1: Preset the block method of the curved surface structure: according to the specifications of the curved surface structure to be prepared, decompose the curved surface structure into spherical blocks and curved surface transition ring blocks; Step 2, cold forming: using a press machine to point press the steel plate of the required size to prepare the required spherical blocks and curved transition ring blocks; Step 3: Tooling production: Produce anti-deformation support tooling for the curved surface structure, and fix each block in the curved surface structure on the support tooling to form an assembly; Step 4, heat treatment: put the assembly into a heat treatment furnace with a first preset temperature below T1°C, then control the heat treatment furnace to heat up to a second preset temperature T2°C at a heating rate V1, and keep it at a preset time tmin, then quickly take it out of the furnace and cool it in water; wherein, T1 is less than 300; T2 is in the range of 580-620; V1 is in the range of 70°C / h-100°C / h; t is in the range of 3T-4T, and T is the thickness of the steel plate; Step 5, assembly welding: the prepared spherical blocks and curved transition ring blocks are fixedly arranged on the supporting fixture according to relative positions, and the spherical blocks and curved transition ring blocks are welded in longitudinal and transverse bidirectional manners by using equal-strength welding materials and matching welding processes; Among them, step two includes: Step S21: selecting steel plates of corresponding specifications for each block according to the sizes and quantities of different spherical blocks and curved transition ring blocks; Step S22: According to the strength, thickness and structural dimensions of the selected steel plate, a press machine is used to perform point pressing processing to prepare the required spherical blocks and curved transition ring blocks; Specifically, in step S22, the point pressing forming of each block includes n point pressing processes, where n is a positive integer; after each point pressing process, the surface radius of the block after the current point pressing process is measured through a sample box, and when the measurement result meets the requirements, the next block is subjected to point pressing forming.

2. The method for manufacturing a thick cold-formed high-strength steel curved surface structure according to claim 1, characterized in that: At least one spherical block and one curved transition ring block are provided.

3. The method for manufacturing a thick cold-formed high-strength steel curved surface structure according to claim 1, characterized in that: The step one comprises: Step S11: according to the curved surface structure specifications to be prepared, decomposing the curved surface structure into spherical blocks and curved surface transition ring blocks; Step S12: obtaining any one or more size factors of the size of the curved surface structure to be prepared, the size of the smelting furnace, and the size of the press respectively; Step S13: Calculate and determine the size and quantity of the spherical blocks and the curved transition ring blocks according to the acquired different types of size data.

4. The method for manufacturing a thick cold-formed high-strength steel curved surface structure according to claim 2, characterized in that: The spherical surface blocks include circular spherical surface blocks and / or sector-shaped spherical surface blocks.

5. The method for manufacturing a thick cold-formed high-strength steel curved surface structure according to claim 1, characterized in that: The step three comprises: Step S31: according to the size of each block in the curved structure, a support tooling with interlaced longitude and latitude is made by using steel; Step S32: fix each block in the curved surface structure on the tooling by spot welding.

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