Forging method for water chamber end socket with pipe nozzle of ultra-large steam generator

Abstract

The invention provides a forging method for a water chamber end socket with a pipe nozzle of an ultra-large steam generator, and belongs to the technical field of metal material forming. In order to solve the problems that the forging profiling degree of the ultra-large steam generator water chamber end socket with the pipe nozzle is not high and operation is difficult, the forging method for the ultra-large steam generator water chamber end socket with the pipe nozzle comprises the steps that S1, a cylindrical blank is prepared; s2, primary shaping; s3, expanding a pipe nozzle; s4, secondary shaping; s5, deep forming; and S6, radial forming. Near-net forming forging of the water chamber end socket with the nozzle of the ultra-large steam generator is achieved through multiple procedures, multiple directions and multiple dies, particularly, the profiling degree of the nozzle position is high, the weight of a steel ingot is small, and the machining difficulty is small.

Description

Technical Field

[0001] This application relates to the field of metal material forming technology, and in particular to a forging method for a water chamber head with nozzle in an ultra-large steam generator. Background Technology

[0002] like Figures 1-2 As shown, the ultra-large steam generator water chamber head with nozzle, represented by the CAP1400 steam generator water chamber head, is characterized by its large size and complex shape. Specifically, the CAP1400 steam generator water chamber head forging is an irregularly shaped head with a diameter of 5.2m, a height of 3.3m, and three long straight nozzles with a length of approximately 2.5m.

[0003] Referring to the forging technology of the Hualong One steam generator water chamber head, which is much smaller in size, the Hualong One water chamber head only has two small inclined nozzles. The maximum radius and maximum height of the inclined nozzles from the centerline do not exceed the size of the Hualong One water chamber head body. Therefore, the Hualong One water chamber head forging can be designed as a frustum-shaped forging that encloses the nozzles and the body and then rotary rolled. For the inclined nozzles of the Hualong One water chamber head, which are relatively short, they can also be further formed by stamping.

[0004] For the CAP1400 steam generator water chamber head forging, the nozzle forging is very long (about 2.5 meters) and has a large radius (about R870mm), making it impossible to form by punching and flanging. If a simple enveloping forging design is adopted, the weight of the steel ingot will reach about 600 tons. The steel ingot is extremely difficult to smelt, and the uniformity and metallurgical quality of the steel ingot are difficult to guarantee. The forging difficulty and equipment load capacity requirements for transportation, lifting, heating, and load are extremely high. The utilization rate of forging materials is very low, and the machining allowance is also very large. This is a disastrous problem for processing and manufacturing costs and cycle control.

[0005] To address the aforementioned issues, existing technologies have also made corresponding improvements. For example, Chinese patent application CN104259369A, published on January 7, 2015, discloses a forging device and method for integral forming of large nuclear reactor water chamber head forgings in the field of nuclear power infrastructure equipment technology. This device includes: a spherical upper punch, a lower forming die with several integral water nozzle forming cavities, and a positioning ring disposed on the lower forming die for supporting the blank. The integral water nozzle forming cavities are disposed on the bottom surface of the spherical cavity of the lower forming die and are connected to an external device of the lower forming die. This invention hot-stamps a preformed blank into an integral head with water nozzles under the load of a heavy-duty hydraulic press. The shortcomings of this scheme are: (1) The nozzle shape of the blank 9 used for stamping is complex, the forging of the blank 9 is very difficult, the processing cycle is long, and the processing allowance of the blank 9 is large; (2) For the irregular head with a long straight nozzle structure, the stiffness of the area where the nozzle is located on the blank is much higher than that of other areas around it. When the blank 9 is bent during the stamping process, the area where the nozzle is located cannot be bent well, and the shape and size of the head near the nozzle are not good; (3) For the irregular head with three long straight nozzle structures, if the nozzle length is greater than the distance from the center of the blank 9 to the center of the nozzle, the far end of the nozzle will cross the center of the blank 9. In this case, the nozzles of the blank 9 have interfered with each other. That is, for the water chamber head with a nozzle length greater than the distance from the center of the blank 9 to the center of the nozzle, it is actually impossible to construct a blank 9 that meets the forming requirements. In other words, this patented method cannot be used to manufacture a water chamber head with a nozzle length greater than the distance from the center of the blank 9 to the center of the nozzle. Summary of the Invention

[0006] The purpose of this application is to solve the problems of low conformity and difficult operation in the forging of water chamber heads with nozzles for ultra-large steam generators in the prior art. Therefore, this application provides a forging method for water chamber heads with nozzles for ultra-large steam generators, which achieves near-net-shape forging through multiple processes, multiple directions, and multiple dies. In particular, the conformity of the nozzle position is high, and the steel ingot weight is small, making machining easier.

[0007] This application provides a forging method for a water chamber head with nozzle for an ultra-large steam generator, including: S1 prepares cylindrical blanks; S2 Initial Shaping: The cylindrical blank is placed in the lower mold II and upset to obtain a preformed part I with a preformed outer spherical surface and a preformed nozzle; the lower mold II has a spherical surface forming area and a nozzle forming area. The spherical surface forming area is used to conform to the outer spherical surface of the water chamber head, and the nozzle forming area is used to position and divide the cylindrical blank for the nozzle position of the water chamber head during upseting, and to restrict the growth direction of the blank, as well as the nozzle of the conformed water chamber head; S3 Extended Nozzle: The preformed part I is reversed so that the preformed nozzle is facing upward, and the preformed nozzle is upset to increase the distance between the preformed nozzle and the center line of the preformed part I, thus obtaining the preformed part II; S4 Secondary Shaping: The preform II is placed upright with the corresponding nozzle facing downwards and is placed in the lower mold II for upsetting to correct the outer spherical surface of the preform II and to make the blank at the nozzle position grow downwards along the nozzle forming area to obtain the preform III; S5 Depth Forming: Lower mold I is stacked on top of lower mold II, and the preform III is placed upright in lower mold I. Upper mold I with a first slope is used to roll the upper end face of preform III, so that the outer contour of preform III fits the inner surface of lower mold I, and preform III is drawn downward and the corresponding nozzle grows. S6 Radial forming: A limiting pad is placed at the bottom of the lower die II, and the upper die II with a second slope is replaced to continue rolling to obtain the final forging; the second slope is less than the first slope, the limiting pad has a nozzle growth limiting area, and the nozzle growth limiting area of ​​the limiting pad cooperates with the nozzle forming area of ​​the lower die II, so that the blank at the corresponding nozzle position is laterally expanded to the final size.

[0008] In some embodiments, the height-to-diameter ratio of the cylindrical blank is 0.85 to 1.

[0009] In some embodiments, during the initial shaping in S2, the upsetting reduction is 600~900mm.

[0010] In some embodiments, the height upsetting amount in the S3 extended nozzle is 200~400mm, and the distance between the outer side of the preformed nozzle and the center line of the preformed part I is increased to ≥2200mm.

[0011] In some embodiments, during the secondary shaping in S4, the upsetting reduction is 700~1000mm.

[0012] In some embodiments, the spinning depth in the S5 depth forming is 1250~1400mm.

[0013] In some embodiments, the S5 depth forming process involves a first angle of 25-35°.

[0014] In some embodiments, during the radial forming of S6, the limiting pad includes an edge guide slope.

[0015] Beneficial effects: This application utilizes a die forging method, combined with multi-process, multi-directional, and multi-mold positioning, material distribution, radius expansion, and spinning forming, to achieve near-net-shape forming of the water chamber head with nozzle for an ultra-large steam generator. The weight of the steel ingot can be reduced to 490 tons, solving the problems of low material utilization, heavy steel ingots, high machining difficulty and long processing time, and difficulty in controlling metal flow in the forging of water chamber head with nozzle for ultra-large steam generators.

[0016] Other features and corresponding beneficial effects of this application will be described in the latter part of the specification, and it should be understood that at least some of the beneficial effects will become obvious from the description in this application. Attached Figure Description

[0017] Figure 1 This is a part drawing of the water chamber head with nozzle of the CAP1400 steam generator; Figure 2 This is a drawing of the forging of the water chamber head with nozzle for a CAP1400 steam generator; Figure 3 This is a structural schematic diagram of lower mold I; Figure 4 This is a structural schematic diagram of the lower mold II; Figure 5 This is a structural schematic diagram of upper mold I; Figure 6 This is a structural schematic diagram of upper mold II; Figure 7 This is a structural schematic diagram of the limiting pad; Figure 8 This is a schematic diagram of the dimensions of the cylindrical blank; Figure 9 This is a schematic diagram of the initial shaping process of S2; Figure 10 This is a schematic diagram of the S3 nozzle expansion process; Figure 11 This is a schematic diagram of the S4 secondary shaping process; Figure 12 This is a schematic diagram of the S5 deep forming process; Figure 13 This is a schematic diagram of the S6 radial forming process; Figure 14 This is a flowchart illustrating the method.

[0018] Explanation of reference numerals in the attached figures: 1. Lower mold I; 2. Lower mold II; 3. Upper mold I; 4. Upper mold II; 5. Limiting pad; 6. Upsetting plate; 7. Turntable; 8. Pad; 10. Cylindrical blank; 11. Preform I; 12. Preform II; 13. Preform III. Detailed Implementation

[0019] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with preferred embodiments, this does not mean that the features of this application are limited to this embodiment. On the contrary, the purpose of describing the application in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of this application. To provide a thorough understanding of this application, many specific details will be included in the following description. This application may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0020] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this application and for simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more. Unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements. When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range. Those skilled in the art will understand the specific meaning of the foregoing terms in this application based on the specific circumstances.

[0022] Please see Figures 1-2 , Figure 1 This is a part drawing of the water chamber head with nozzle of the CAP1400 steam generator; Figure 2 This is a drawing of the forging of the water chamber head with nozzle of the CAP1400 steam generator.

[0023] It is evident that, compared to the Hualong One (with two short nozzles), the CAP1400 steam generator water chamber head is not only larger in overall size but also features three distinct long straight nozzles. For the CAP1400 steam generator water chamber head forging, to reduce allowance and ingot weight, it is preferable to forge three long straight nozzles using a contour forging process. However, the nozzle length of the CAP1400 steam generator water chamber head forging reaches 2.5m, and the distance from the outer edge of the nozzle to the centerline of the forging is approximately 2.4m. During the actual contour forging process, it was found that achieving sufficient and effective filling of the nozzles was very difficult, easily leading to insufficient nozzle dimensions.

[0024] Therefore, this application provides a forging method for a water chamber head with nozzle of an ultra-large steam generator. It achieves near-net-shape forging through multiple processes, directions, and dies. In particular, the nozzle position has a high degree of conformity, and the steel ingot is relatively small in weight, making machining easier.

[0025] like Figure 14 As shown, this method includes: S1 Prepares cylindrical blank 10.

[0026] Specifically, after multiple large-ratio upsetting, WHF high-pressure and JTS core compaction, and removal of risers and nozzles, the steel ingot is pressed into a shape as follows: Figure 8 The cylindrical blank 10 shown has a height of H0 and a diameter of D0.

[0027] In one embodiment, the height-to-diameter ratio of the cylindrical billet 10 is 0.85 to 1. If the height-to-diameter ratio of the cylindrical billet 10 is too small, the billet height will be too low, and even after subsequent rotary rolling and deep drawing, the forging height will still be lower than the design requirements. At the same time, this application requires separate forging of the nozzle. If the height-to-diameter ratio is too large, the billet diameter will be too small, and the radial dimension of the pre-formed nozzle after upsetting will be too small. Even after subsequent upsetting to expand the nozzle size, the nozzle size will still not meet the design requirements.

[0028] S2 initial shaping, also known as one upsetting of the billet, achieves positioning and material distribution.

[0029] Specifically, such as Figure 9 As shown, the cylindrical blank 10 is placed in the lower mold II2 and upset by the upsetting plate 6 to obtain the preformed part I11 with a preformed outer spherical surface and a preformed nozzle, thus realizing the positioning and material distribution.

[0030] It should be noted that the bottom of the lower die II2 has a through-hole to control its weight. Therefore, during the forging process, a backing plate 8 is placed under the lower die II2 to ensure forging quality.

[0031] like Figure 4 As shown, the lower mold II2 has a spherical forming area and a nozzle forming area. The spherical forming area is used to shape the outer spherical surface of the water chamber head, that is, to position and divide the cylindrical blank 10 for the outer spherical surface of the water chamber head during upsetting, and finally shape it. The nozzle forming area is used to position and divide the cylindrical blank 10 for the nozzle position of the water chamber head during upsetting, and to restrict the growth direction of the blank, as well as shape the nozzle of the water chamber head.

[0032] The nozzle forming area is usually a cavity that expands outward from the spherical forming area corresponding to the nozzle contour position.

[0033] In one specific embodiment, the large forging has three nozzles evenly distributed at 120°, thus the nozzle forming area is provided with three nozzles evenly distributed at 120°.

[0034] In one embodiment, during the initial shaping in S2, the upsetting reduction is 600-900 mm, such as 600 mm, 700 mm, or 850 mm, to press the outer spherical shape of the water chamber head onto the cylindrical blank 10 and to position and divide the material for the nozzle. During subsequent forging, the nozzle grows directionally along the divided position. Furthermore, if the reduction is too small, the initially formed nozzle size will be too small, and the nozzle size after subsequent upsetting will not meet the design requirements; if the reduction is too large, the final forging height will be insufficient.

[0035] S3 extended nozzle, which is the radius of the upsetting nozzle extended nozzle to the center line of the billet.

[0036] It should be noted that the blank in the nozzle area is formed by entering the nozzle cavity, but the nozzle cavity itself does not directly participate in forming the size and shape of the nozzle part. At the beginning of upsetting, the radius of the blank is significantly smaller than the radial dimension from the nozzle to the center line. If upsetting is carried out directly in this state, the blank in the nozzle cavity can only grow downwards by a small radial dimension, resulting in a nozzle with insufficient radial dimension.

[0037] Therefore, this application expands the nozzle, that is, the blank of the nozzle part is expanded by upsetting, so that when it is upset again, the blank of the nozzle part can grow the nozzle height downward along the existing nozzle radial dimension.

[0038] Specifically, such as Figure 10 As shown, the preformed part I11 is reversed so that the preformed nozzle is facing upward, and the preformed nozzle is upset to increase the distance between the preformed nozzle and the center line of the preformed part I11, thereby ensuring that the nozzle size can grow to the required size during the subsequent forging process.

[0039] This step involves placing the preform I11 on a turntable 7 and using a flat anvil for rotating upsetting to obtain the preform II12.

[0040] In one embodiment, the height upsetting amount in the S3 extended nozzle is 200~400mm, such as 200mm, 300mm or 400mm, to balance the height of the forging and the radial dimension of the nozzle from the center line, and to increase the distance between the outer side of the preformed nozzle and the center line of the preformed part I11 to ≥2200mm.

[0041] S4 secondary shaping, also known as secondary upsetting of billet and secondary shaping of spherical surface and material distribution nozzle.

[0042] Specifically, such as Figure 11As shown, the preform II12 is placed upright with the corresponding nozzle facing downwards and is placed in the lower mold II2 for upsetting to correct the outer spherical surface of the preform II12 that was deformed by S3, and to make the blank at the nozzle position grow downwards along the nozzle forming area to obtain the preform III13.

[0043] In one embodiment, during the secondary shaping in S4, the upsetting reduction is 700~1000mm, such as 700mm, 900mm, 1000mm, etc., to balance the nozzle height and the forging height, avoiding insufficient nozzle height due to too small a reduction, and insufficient forging height due to too large a reduction.

[0044] S5 deep forming, also known as upper die I3 spinning to expand the outer diameter of the blank, draw the spherical surface and grow the nozzle height.

[0045] Specifically, such as Figure 12 As shown, the lower die I1 is stacked above the lower die II2, and the preform III13 is placed upright in the lower die I1. The upper die I3 with a first slope is used to spin roll the upper end face of the preform III13, so that the outer contour of the preform III13 fits with the inner surface of the lower die I1, and the preform III13 is drawn downward and the corresponding nozzle grows. That is, the outer diameter of the billet is expanded to the size of the forging by the spin roll of the upper die I3, and the billet is subjected to radial resistance after contacting the inner surface of the lower die I1, which promotes the downward drawing of the billet into a spherical surface and the growth of the nozzle height during the spin roll forging process. The nozzle grows to a height close to the size of the forging.

[0046] like Figure 3 As shown, the lower die I1 is in the shape of a ring. When it is stacked on the lower die II2, they are used together to form the outer contour of the forging.

[0047] Preferably, the lower die I1 has a straight forming area and a transition spherical forming area, which are used to make the upper outer contour of the preformed part III13 conform to the upper part of the forging spherical surface that is close to the vertical part (usually the slope of this part is about 3°) and the spherical part close to this part as it is rolled.

[0048] This design ensures that after the billet is rolled until it is clamped by the lower die I1, the diameter of the straight section of the head meets the process design requirements. At this point, the lower die I1 can be discarded and the rolling can continue to avoid the clamping problem and improve the forming quality. Meanwhile, the lower die I1 has a part of the spherical surface, which can realize the function of lifting the billet through the lower die I1. The lower die 2 has complete nozzle features and most of the spherical features. Continuing to roll can ensure the main structural features of the head.

[0049] like Figure 5As shown, the first angle of the upper die I3 is 25~35°, for example 30°, which can take into account both radial expansion and height growth, and is highly efficient. Specifically, if the angle is too small, the diameter of the forging cannot expand rapidly, and it is easy to jam the die after the billet comes into contact with both the upper die I3 and the lower die I1 in the later stage of rotary rolling. If the angle is too large, the difference in wall thickness between the upper and lower parts of the billet will be too large, which does not meet the design requirements. The amount of billet cannot be correctly distributed, which will cause insufficient filling in other areas. In addition, the upper diameter expands too quickly, which may result in insufficient end wall thickness.

[0050] In one embodiment, during the S5 deep forming process, the spinning depth is 1250~1400mm, such as 1250mm, 1300mm, or 1400mm, to ensure forming quality. Specifically, when the spinning depth is low, the amount of spinning deformation left for S6 is too large, making it impossible to complete the operation within the limited hot forging time; when the spinning depth is large, due to the large die angle, the upper diameter of the billet expands too quickly after exceeding this spinning depth, resulting in excessive reduction of the wall thickness.

[0051] S6 radial forming, that is, upper die II4 spinning to expand the inner cavity space, deepen the nozzle height, and expand the nozzle radius.

[0052] Specifically, such as Figure 13 As shown, a limiting pad 5 is placed at the bottom of the lower die II2, and the upper die II4 with the second slope is replaced to continue rolling to obtain the final forging.

[0053] like Figure 6 As shown, the second slope is smaller than the first slope, that is, the upper die II4 with a smaller slope, wider and deeper is selected to rotate and roll the inner cavity of the billet, expand the inner cavity space of the billet to meet the inner cavity size requirements of the forging, and make the nozzle height reach the size of the forging during the spinning process.

[0054] like Figure 7 As shown, the limiting plate 5 has a nozzle growth limiting area, and the nozzle growth limiting area of ​​the limiting plate 5 cooperates with the nozzle forming area of ​​the lower die II2, so that the blank at the corresponding nozzle position expands laterally to the final size. That is, the upper die II4 continues to spin, and under the restriction of the limiting plate 5 and the lower die II2, the nozzle changes from a downward growth height to a further lateral expansion radius, ensuring the nozzle size. Specifically, after the bottom center of the blank contacts the limiting plate 5, it can no longer grow downward. The blank from the upper spinning belt can only fill the nozzle area laterally. After the nozzle fills downward to contact the press table, the subsequent supplementary blanks obtained from above can only fill the nozzle cavity that was not filled during the previous spinning process laterally, further expanding the nozzle radius laterally.

[0055] In one embodiment, during radial forming in S6, the limiting pad 5 includes an edge guide slope, preferably with a slope of 20 to 30°, to guide the blank toward the outer edge of the lower mold II2.

[0056] Example 2: Referring to Example 1, this example provides a forging method for a water chamber head with nozzle of a specific size for an ultra-large steam generator, including: S1 Preparation of Cylindrical Billet 10: After multiple large forging ratio upsetting, WHF strong pressing and JTS core compaction, and removal of risers and sprues, 490 tons of steel ingots are pressed into cylindrical billet 10 with a diameter of approximately Φ3790mm and a height of approximately 3450mm.

[0057] S2 initial shaping: The blank is upset in the lower mold II2 with an upsetting reduction of 700mm. The outer spherical shape of the water chamber head is pressed into the blank, and the nozzle position is positioned and divided to obtain the preform I11.

[0058] S3 Extended Nozzle: Invert the blank with the nozzle facing upward, and upset the three nozzle distribution areas. Extend the nozzle radius from the blank centerline and the upset amount is about 300mm. Extend the distance from the outer side of the nozzle to the centerline to ≥2200mm to obtain the preform II12.

[0059] S4 Secondary Shaping: The blank is reversed again with the nozzle facing downwards. The blank is upset in the lower mold II2 with an upsetting reduction of 900mm. The spherical shape, which has changed in S3, is reshaped. The blank at the nozzle position grows downwards along the nozzle forming area of ​​the lower mold II2 to obtain the preformed part III13.

[0060] S5 Depth Forming: Place the lower mold I1 on the lower mold II2, and use the upper mold I3 with a large slope (e.g., 30°) to rotate and roll the upper end face of the blank, with a spinning depth of 1300mm.

[0061] S6 Radial Forming: A limiting pad 5 is placed at the bottom of the lower die II2, which together with the lower die II2 forms a limiting position on the bottom of the water chamber head forging. Using the upper die II4, the inner cavity of the billet is rotated and rolled to a depth of 1900mm to obtain the final forging.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A forging method for a water chamber head with nozzle for an ultra-large steam generator, characterized in that, include: S1 prepares cylindrical blanks; S2 Initial Shaping: The cylindrical blank is placed in the lower mold II and upset to obtain a preformed part I with a preformed outer spherical surface and a preformed nozzle; the lower mold II has a spherical surface forming area and a nozzle forming area. The spherical surface forming area is used to conform to the outer spherical surface of the water chamber head, and the nozzle forming area is used to position and divide the cylindrical blank for the nozzle position of the water chamber head during upseting, and to restrict the growth direction of the blank, as well as the nozzle of the conformed water chamber head; S3 Extended Nozzle: The preformed part I is reversed so that the preformed nozzle is facing upward, and the preformed nozzle is upset to increase the distance between the preformed nozzle and the center line of the preformed part I, thus obtaining the preformed part II; S4 Secondary Shaping: The preform II is placed upright with the corresponding nozzle facing downwards and is placed in the lower mold II for upsetting to correct the outer spherical surface of the preform II and to make the blank at the nozzle position grow downwards along the nozzle forming area to obtain the preform III; S5 Depth Forming: Lower mold I is stacked on top of lower mold II, and the preform III is placed upright in lower mold I. Upper mold I with a first slope is used to roll the upper end face of preform III, so that the outer contour of preform III fits the inner surface of lower mold I, and preform III is drawn downward and the corresponding nozzle grows. S6 Radial forming: A limiting pad is placed at the bottom of the lower die II, and the upper die II with a second slope is replaced to continue rolling to obtain the final forging; the second slope is less than the first slope, the limiting pad has a nozzle growth limiting area, and the nozzle growth limiting area of ​​the limiting pad cooperates with the nozzle forming area of ​​the lower die II, so that the blank at the corresponding nozzle position is laterally expanded to the final size.

2. The forging method for the water chamber head with nozzle of the ultra-large steam generator according to claim 1, characterized in that, The height-to-diameter ratio of the cylindrical blank is 0.85~1.

3. The forging method for the water chamber head with nozzle of the ultra-large steam generator according to claim 1, characterized in that, In the initial shaping of S2, the upsetting reduction is 600~900mm.

4. The forging method for the water chamber head with nozzle of the ultra-large steam generator according to claim 1, characterized in that, In the S3 extended nozzle, the height upsetting amount is 200~400mm, and the distance between the outer side of the preformed nozzle and the center line of the preformed part I is increased to ≥2200mm.

5. The forging method for the water chamber head with nozzle of the ultra-large steam generator according to claim 1, characterized in that, In the S4 secondary shaping process, the upsetting reduction is 700~1000mm.

6. The forging method for the water chamber head with nozzle of the ultra-large steam generator according to claim 1, characterized in that, In the S5 deep forming process, the spinning depth is 1250~1400mm.

7. The forging method for the water chamber head with nozzle of the ultra-large steam generator according to claim 1, characterized in that, The S5 depth forming process involves a first angle of 25-35°.

8. The forging method for the water chamber head with nozzle of the ultra-large steam generator according to claim 1, characterized in that, In the radial forming of S6, the limiting pad includes an edge guide slope.

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