A nozzle forming tool and forming method for large-diameter cylindrical forgings

Abstract

The present invention relates to a side tube forming tool and forming method for a large-diameter cylinder, belonging to the technical field of cylinder tube forging technology, and solves the technical problem of limited press space travel when preparing tubes for large-diameter cylinders in the prior art. The tube forming tool of the present invention includes an upper crossbeam assembly, an intermediate crossbeam assembly, a forming lower die assembly, a supporting lower die assembly, and a stroke increasing block. The present invention can realize the flanging extrusion forming of the side tube of a large-diameter cylinder inside the press, which can effectively solve the problem of limited press space travel and realize the contour forging of the integrated tube section of a large-size nuclear power tube.

Description

Technical Field

[0001] The present invention relates to the technical field of forging forming, and in particular to a nozzle forming tool and a forming method for a large-diameter cylindrical forging. Background Art

[0002] The take-over section is one of the key components of nuclear reactor pressure vessel equipment. Figure 1 It is located in the middle of the entire nuclear reactor pressure vessel. It withstands high temperature, high pressure and high radioactivity during service and is the core component of the first safety barrier of the nuclear reactor.

[0003] Currently, welding is used to join the inlet / outlet nozzles to the nozzle section barrel. This not only requires a large welding workload, but also requires repeated preheating and post-weld heat treatment during the welding process. Multiple thermal cycles can degrade the forging performance. Furthermore, during the operation of the nuclear power unit, the weld locations require in-service inspections, which limits the efficiency of in-service inspections. As the design life of nuclear power units increases and safety levels rise, the quality requirements for their components become increasingly stringent, and the design of nozzle sections is gradually moving towards integration.

[0004] At present, there are two main forging methods for this type of forgings. The first forging method is to forge an oversized cylinder with a ring belt, which will cover the pipe envelope. Figure 2 To fully envelop the nozzle, the wall thickness of the annular band is extremely thick, and the metal streamlines are incomplete, resulting in poor forgeability and difficulty in ensuring subsequent performance. The second forging method involves forging the barrel, using a flanging method to form the nozzle. This method ensures uniform deformation of the nozzle and complete metal streamlines, meeting the homogenization requirements of large nuclear power forgings. However, the nozzle sections of current third-generation nuclear power units are extremely large. If the second forging method is used, the current nozzle forming tooling structure and the spatial dimensions of the forging hydraulic press will not meet manufacturing requirements. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a forming tool and forming method for the pipe of a large-diameter cylindrical forging, so as to solve the technical problem in the prior art that the flanging forming of the pipe of a large-diameter cylindrical forging cannot be achieved inside the press due to the limited spatial stroke of the press.

[0006] The purpose of the present invention is mainly achieved through the following technical solutions:

[0007] In one aspect, the present invention provides a nozzle forming tool for a large-diameter cylindrical forging, comprising an upper crossbeam assembly, an intermediate crossbeam assembly, a forming lower die assembly, and a supporting lower die assembly;

[0008] The upper crossbeam assembly is connected to the movable crossbeam of the forging hydraulic press, which can drive the upper crossbeam assembly to move in the upward and downward directions; the upper crossbeam assembly is used to transmit force to the intermediate crossbeam assembly located below;

[0009] The middle crossbeam assembly includes a forming portion, which is used to form the pipe forming portion on the large-diameter cylindrical forging. The middle crossbeam assembly is connected to a forging manipulator. The forging manipulator can drive the middle crossbeam assembly to move horizontally to the bottom of the forging hydraulic press and align it vertically with the upper crossbeam assembly.

[0010] The forming lower die assembly is arranged below the large-diameter cylindrical forging and is used to withstand the pressure applied by the butt-tube forming part of the forging hydraulic press; the supporting lower die assembly is used to support the forming lower die and the large-diameter cylindrical forging.

[0011] In one possible design, the upper crossbeam assembly includes an upper crossbeam, a first vertical beam, and a second vertical beam; the height of the first vertical beam is greater than the height of the second vertical beam;

[0012] The first vertical beam is assembled on one side of the bottom surface of the upper crossbeam, and the second vertical beam is assembled on the other side; the height difference between the first vertical beam and the second vertical beam is △H1.

[0013] In a possible design, the middle crossbeam assembly further includes a force-transmitting crossbeam and a third vertical beam;

[0014] The force transmission beam is connected to the forging manipulator, which can move the middle beam assembly to the bottom of the upper beam assembly;

[0015] The third vertical beam is vertically arranged on one side of the upper end surface of the force transmission beam, and the third vertical beam is aligned with the second vertical beam; the height of the third vertical beam is △H1;

[0016] The forming part is arranged on the lower end surface of the force transmission beam; the forming part and the force transmission beam are detachably connected.

[0017] In one possible design, the forming portion includes a forming punch, which includes a cylindrical portion and a peach-shaped portion; a first end of the cylindrical portion is detachably connected to the force-transmitting crossbeam, and a second end of the cylindrical portion is connected to the peach-shaped portion;

[0018] The diameter of the cylindrical portion is smaller than the maximum diameter of the peach-shaped portion;

[0019] A conical pipe forming guide hole is provided at the pipe forming portion on the large-diameter cylindrical forging; a forging hydraulic press applies pressure to a forming punch through an upper crossbeam assembly and a lower crossbeam assembly, so that the forming punch performs flanging forming on the conical pipe forming guide hole.

[0020] In one possible design, a vertical pin hole is provided on the force transmission beam and passes through the force transmission beam; a connecting vertical pin is provided in the vertical pin hole; the upper end of the connecting vertical pin is provided with a first pin hole, and the upper horizontal pin is provided in the first pin hole; the lower end of the connecting vertical pin is provided in the second pin hole;

[0021] A transverse pin hole is provided on the first end of the cylindrical portion, and a transverse pin is provided in the transverse pin hole;

[0022] A third vertical pin hole is also provided on the first end of the columnar portion, the second end of the connecting vertical pin is embedded in the third pin hole, and the second pin hole at the lower end of the connecting vertical pin is aligned with the transverse pin hole; the transverse pin passes through the transverse pin hole and the second pin hole.

[0023] In a possible design, the pipe forming portion is a pipe boss;

[0024] The forming lower die assembly includes a forming lower die, a first supporting block and a second supporting block, wherein the first supporting block and the second supporting block are arranged on the outer side of the forming lower die;

[0025] The forming lower die is provided with a first hollow annular cavity, and the connecting pipe boss is arranged in the first hollow annular cavity; the first supporting block and the second supporting block are both used for supporting the boss shoulder of the connecting pipe boss.

[0026] In one possible design, the supporting lower mold assembly includes a supporting column, in which a second hollow annular cavity is provided. The second hollow annular cavity is provided below the first hollow annular cavity and the central axes of the two are aligned; the second hollow annular cavity is used to accommodate a forming punch.

[0027] In one possible design, the forging hydraulic press includes a hydraulic press feed table; a third hollow annular cavity is provided in the hydraulic press feed table, and the supporting lower die assembly is provided in the third hollow annular cavity of the hydraulic press feed table and passes through the hydraulic press feed table; the hydraulic press feed table is used to support and move the lower die assembly, the forming lower die group and the large-diameter cylindrical forging.

[0028] In a possible design, the pipe forming tool further includes a plurality of stroke increasing blocks; the stroke increasing blocks are provided at the first end of the cylindrical portion of the forming punch;

[0029] The stroke increasing block is used to increase the stroke of the forming punch.

[0030] On the other hand, the present invention also provides a method for forming a nozzle of a large-diameter cylindrical forging, using the above-mentioned nozzle forming tool for a large-diameter cylindrical forging, the forming method comprises the following steps:

[0031] Step 1: prefabricate a large-diameter cylinder blank with steps, and process a tapered pipe forming guide hole at the pipe forming portion of the large-diameter cylinder blank. After processing, locally heat the pipe forming portion.

[0032] Step 2: Place the large-diameter cylindrical blank on the supporting lower die assembly and the forming lower die assembly, and embed the pipe forming portion into the first hollow annular cavity;

[0033] Step 3: Move the hydraulic press feed table and move the large-diameter cylinder blank together with the forming lower die assembly and the supporting lower die assembly from the side of the second vertical beam of the upper crossbeam assembly into the forging hydraulic press;

[0034] Step 4: The forging manipulator clamps the middle crossbeam assembly and moves it into the large-diameter cylinder blank. The upper crossbeam assembly and the middle crossbeam assembly are aligned. After the forming punch is aligned with the tapered tube forming guide hole, the tube is pre-formed. When the stroke limit of the forging hydraulic press is reached and the upper crossbeam is about to contact the cylinder, the pressing is stopped.

[0035] Step 5: Remove the lower cross pin connected to the forming punch and lift the upper cross beam assembly; leave the forming punch in place, use the forging manipulator to clamp the middle cross beam assembly and lift it;

[0036] Step 6: Install the stroke increasing block above the forming punch, lower the middle crossbeam assembly and continue forming the pipe. When the stroke limit of the forging hydraulic press is reached again and the upper crossbeam is about to contact the cylinder, stop pressing down;

[0037] Step 7: Lift the upper crossbeam assembly, use the forging manipulator to clamp the middle crossbeam assembly and lift it, and place the stroke increase block again;

[0038] Step 8: Lower the middle crossbeam assembly and continue forming the pipe until it is finished.

[0039] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0040] (1) The present invention can effectively solve the problem of limited space travel of the press, and realize the flanging of the pipes of large-diameter cylindrical forgings inside the press, especially the flanging of the integrated pipe sections of large-size nuclear power pressure vessels with pipes, thereby eliminating the need for welds, ensuring complete metal streamlines of the forgings and uniform deformation of all parts, thus meeting the homogenization requirements of ultra-large nuclear power forgings; at the same time, it can also shorten the manufacturing cycle, reduce manufacturing costs, and reduce subsequent in-service inspection work.

[0041] (2) The present invention adopts a design in which the height of the first beam is equal to the sum of the heights of the second beam and the third beam. On the one hand, it can ensure the balance of the force-transmitting beam when the upper beam assembly is pressed down; on the other hand, it can ensure the accuracy of the pipe forming while achieving force transmission.

[0042] (3) The present invention can firmly fix the large-diameter cylindrical forging through the forming lower die, the first support block and the second support block and can withstand the downward pressure applied by the forging hydraulic press, thereby ensuring that the pipe forming part of the large-diameter cylindrical forging will not shake when subjected to pressure, thereby ensuring the accuracy of the pipe forming.

[0043] (4) The design of combining the supporting lower die assembly with the hydraulic press feed table (i.e., embedding the supporting lower die assembly in the hydraulic press feed table) makes full use of the space below the press feed table and further expands the space for forming the flange of the pipe of the diameter cylinder forging.

[0044] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages will become apparent from the description or be understood through practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the embodiments of the description and the contents particularly pointed out in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0046] Figure 1 This is a parts drawing of an integrated pipe section with a pipe;

[0047] Figure 2 This is a diagram of a ring-band enveloping forging;

[0048] Figure 3 A schematic diagram of the nozzle forming tooling structure and assembly of a large-diameter cylindrical forging provided by the present invention;

[0049] Figure 4 It is a schematic diagram of the prefabricated cylinder of the present invention;

[0050] Figure 5 is a schematic diagram of the upper crossbeam assembly of the present invention;

[0051] Figure 6 Schematic diagram of the middle crossbeam assembly;

[0052] Figure 7a Schematic diagram of the pipe flanging extrusion process Figure 1 ;

[0053] Figure 7b Schematic diagram of the pipe flanging extrusion process Figure 2 ;

[0054] Figure 7c Schematic diagram of the pipe flanging extrusion process Figure 3 ;

[0055] Figure 7d Schematic diagram of the pipe flanging extrusion process Figure 4 ;

[0056] Figure 7e Schematic diagram of the pipe flanging extrusion process Figure 5 ;

[0057] Figure 7f Schematic diagram of the pipe flanging extrusion process Figure 6 .

[0058] Reference numerals:

[0059] 1-large diameter cylindrical blank; 101-tapered pipe forming guide hole; 2-upper crossbeam assembly; 201-upper crossbeam; 202-first vertical beam; 203-second vertical beam; 3-middle crossbeam assembly; 301-force transmission crossbeam; 302-third vertical beam; 303-upper cross pin; 304-connecting vertical pin; 305-lower cross pin; 306-forming punch; 401-forming lower die; 402-first supporting block; 403-second supporting block; 404-supporting lower die; 405-hydraulic press feed table; 5-stroke raising block; 6-forging manipulator. DETAILED DESCRIPTION

[0060] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0061] Example 1

[0062] The present invention provides a pipe forming tool for large-diameter cylindrical forgings, comprising an upper crossbeam assembly 2, an intermediate crossbeam assembly 3, a forming lower die assembly and a supporting lower die assembly; the upper crossbeam assembly 2 is connected to the movable crossbeam of a forging hydraulic press, and the movable crossbeam of the forging hydraulic press can drive the upper crossbeam 201 of the upper crossbeam assembly 2 to move in the upper and lower directions; the upper crossbeam assembly 2 is used to transmit force to the intermediate crossbeam assembly 3 provided below; the intermediate crossbeam assembly 3 includes a forming part, and the forming part is used to form the pipe forming part on the large-diameter cylindrical forging; the intermediate crossbeam assembly 3 is connected to a forging manipulator 6; the forging manipulator 6 can drive the intermediate crossbeam assembly 3 to move horizontally to the bottom of the forging hydraulic press, and be aligned with the upper crossbeam assembly 2 up and down; the forming lower die assembly is provided below the large-diameter cylindrical forging, and the forming lower die assembly is used to withstand the pressure applied by the forging hydraulic press to the pipe forming part; the supporting lower die assembly is used to support the forming lower die 401 and the large-diameter cylindrical forging.

[0063] Specifically, if Figures 3 to 7fAs shown, the present invention provides a pipe (side pipe) forming tool for large-diameter cylindrical forgings. This pipe forming tool is mainly used for pipe section components with a cylindrical outer diameter greater than or equal to 5000-5500mm and a weight of 250-300 tons. The pipe forming tool includes an upper crossbeam assembly 2, an intermediate crossbeam assembly 3, a forming lower die assembly, and a supporting lower die assembly. The upper crossbeam assembly 2 is connected to the movable beam of the forging hydraulic press, and the movable beam can drive the upper crossbeam assembly 2 to move in the upward and downward directions. The intermediate crossbeam assembly 3 is provided below the upper crossbeam assembly 2, and the lower end surface of the intermediate crossbeam assembly 3 is provided with a forming portion. The large-diameter cylindrical forging is fixed to the forming lower die assembly and the supporting lower die assembly, and the supporting lower die assembly is embedded in the hydraulic press feed table 405.

[0064] When the large-diameter cylindrical forging is undergoing pipe forming, the large-diameter cylindrical forging is first moved into the forging hydraulic press by moving the hydraulic press feeding table 405, and then the middle beam assembly 3 is moved into the forging hydraulic press by the forging operating machine 6 and is located directly below the upper beam assembly 2; in addition, the pipe forming part of the large-diameter cylindrical forging and the forming part of the middle beam are aligned up and down. At this time, the movable beam of the forging hydraulic press is used to drive the upper beam assembly 2 to move downward. After receiving the pressure, the upper beam assembly 2 presses the middle beam assembly 3 downward, and the middle beam assembly 3 drives the forming part to form the pipe at the pipe forming part of the large-diameter cylindrical forging.

[0065] There are two main ways to form the nozzles of existing large diameter cylinder forgings: one is to forge an oversized cylinder with a ring band, which covers the nozzle, such as Figure 2 As shown in the figure, in order to fully cover the nozzle, the wall thickness of the ring position is extremely large, the metal streamline is incomplete, the forgeability is poor, and the subsequent performance is difficult to guarantee; another nozzle forming method is: forging the cylinder and forming the nozzle by nozzle flanging forming. This method can ensure uniform deformation of the nozzle position and complete metal streamlines, meeting the homogenization requirements of large nuclear power forgings, but this forming method is only applicable to nozzle section components with smaller dimensions, and cannot be applied to nozzle section components of large nuclear power units, that is, the current nozzle forming tooling structure and press space size are difficult to meet manufacturing requirements.

[0066] Compared with the prior art, the pipe forming tool for large-diameter cylinders provided by the present invention is mainly suitable for forming pipes of large-diameter cylinder forgings with an outer diameter of the cylinder greater than or equal to 5200 mm; in the vertical direction, the pipe forming tool provided by the present invention saves at least 2700 mm of space compared with the existing pipe forming tool. The use of the pipe forming tool provided by the present invention can effectively solve the problem of limited space stroke of the press, and thus can realize the flanging extrusion forming of the pipe of the large-diameter cylinder forgings inside the forging hydraulic press, thereby realizing the integrated contour forging of the pipe of the large-diameter cylinder forgings.

[0067] In order to ensure that the large-diameter cylindrical forging can be moved into the forging hydraulic press from one side of the upper crossbeam assembly 2, the upper crossbeam assembly 2 of the present invention includes an upper crossbeam 201, a first vertical beam 202 and a second vertical beam 203; the height of the first vertical beam 202 is greater than the height of the second vertical beam 203; the first vertical beam 202 is assembled on one side of the bottom surface of the upper crossbeam 201, and the second vertical beam 203 is assembled on the other side; the height difference between the first vertical beam 202 and the second vertical beam 203 is △H1.

[0068] Specifically, if Figure 5 As shown, the upper crossbeam assembly 2 provided by the present invention includes an upper crossbeam 201, a first vertical beam 202 and a second vertical beam 203, wherein the height of the first vertical beam 202 is greater than the height of the second vertical beam 203, the first vertical beam 202 is assembled on one side of the lower end face of the upper crossbeam 201, and the second crossbeam is assembled on the other side of the lower end face of the upper crossbeam 201. When the pipe forming part of the large-diameter cylindrical forging is subjected to pipe forming, the large-diameter cylindrical forging fixed on the forming lower die assembly and the supporting lower die assembly is moved from the side of the second vertical beam 203 into the forging hydraulic press.

[0069] The existing pipe forming tooling generally lifts the upper crossbeam 201 structure and then moves the large-diameter cylindrical forging into the forging hydraulic press. The present invention adopts a design of unequal heights by setting the first vertical beam 202 and the second vertical beam 203. After the large-diameter cylindrical forging is fixed to the lower die forming assembly and the lower die support assembly, it can be smoothly moved from the side of the second vertical beam 203 into the interior of the forging hydraulic press, thereby saving the internal space of the forging hydraulic press.

[0070] In order to ensure the forming accuracy of the connecting pipe, the middle beam assembly 3 of the present invention also includes a force transmission beam 301 and a third vertical beam 302; the force transmission beam 301 is connected to the forging operation machine 6, and the forging operation machine 6 can move the middle beam assembly to the bottom of the upper beam assembly 2; the third vertical beam 302 is vertically arranged on one side of the upper end face of the force transmission beam 301, and the third vertical beam 302 is aligned with the second vertical beam 203; the height of the third vertical beam 302 is △H1; the forming part is arranged on the lower end face of the force transmission beam 301; the forming part and the force transmission beam 301 are detachably connected.

[0071] Specifically, if Figure 6As shown in FIG7 , the intermediate crossbeam assembly 3 of the present invention further includes a force-transmitting crossbeam 301 and a third vertical beam 302. The first end of the force-transmitting crossbeam 301 is connected to the forging operating machine 6. The forging operating machine 6 applies a horizontal force to the force-transmitting crossbeam 301, so that the force-transmitting crossbeam 301 can move in the horizontal direction, including moving into the bottom of the upper crossbeam assembly 2, that is, moving into the interior of the forging hydraulic press, or moving out of the forging hydraulic press. The second end of the force-transmitting crossbeam 301 is used to support the first vertical beam 202. In addition, it should be noted that the third vertical beam 302 is vertically arranged on the upper end surface of the first end of the force-transmitting crossbeam 301, and the third crossbeam is aligned with the above-mentioned second crossbeam. When aligned, the third vertical beam 302 of the intermediate crossbeam assembly 3 abuts against the end of the second vertical beam 203 of the upper crossbeam assembly 2, and the height of the third crossbeam is △H1.

[0072] Compared with the prior art, the present invention adopts a design in which the height of the first beam is equal to the sum of the heights of the second beam and the third beam. On the one hand, it can ensure the balance of the force transmission beam 301 when the upper beam assembly 2 is pressed down. On the other hand, it can ensure the accuracy of the pipe forming while achieving force transmission.

[0073] It should be noted that a groove is provided on the lower end surface of the second horizontal beam 203, and a protrusion is provided on the upper end surface of the third vertical beam 302. When the second vertical beam 203 and the third vertical beam 302 are aligned, the protrusion on the third horizontal beam 302 is embedded in the groove of the second horizontal beam 203, thereby ensuring that the second vertical beam 203 and the third vertical beam 302 are aligned.

[0074] In order to facilitate demolding of the forming part after the pipe is formed, the forming part of the present invention includes a forming punch 306, and the forming punch 306 includes a cylindrical part and a peach-shaped part; the first end of the cylindrical part is detachably connected to the force transmission beam 301, and the second end of the cylindrical part is connected to the peach-shaped part; the diameter of the cylindrical part is smaller than the maximum diameter of the peach-shaped part; the pipe forming part on the large-diameter cylindrical forging is provided with a tapered pipe forming guide hole 101; the forging hydraulic press applies pressure to the forming punch 306 through the upper beam assembly 2 and the lower beam assembly, so that the forming punch 306 performs flanging on the tapered pipe forming guide hole 101.

[0075] Specifically, if Figure 6 and Figures 7a to 7fAs shown, the forming part of the present invention includes a forming punch 306, which includes a cylindrical part and a peach-shaped part, and the cylindrical part and the peach-shaped part are formed as one piece; the first end (upper end) of the cylindrical part is detachably connected to the lower end face of the force transmission beam 301, and the second end of the cylindrical part is fixedly connected to the peach-shaped part; it should be noted that the diameter of the cylindrical part is smaller than the maximum diameter of the peach-shaped part, and the forming part adopts a peach-shaped design with a "big head and small body", which can facilitate the demolding of the forming punch 306 after the forming of the pipe is completed. It should be noted that a pipe forming portion is provided on the large-diameter cylindrical forging, and a tapered pipe forming guide hole 101 is provided at the pipe forming portion, and the tapered pipe forming guide hole 101 is aligned with the forming punch 306 in the vertical direction; when the pipe is formed at the pipe forming portion, the forging hydraulic press applies pressure to the force transmission beam 301 through the first vertical beam 202 and the second vertical beam 203 of the upper beam assembly 2, and the force transmission beam 301 applies downward pressure to the forming punch, and the forming punch 306 performs flanging on the tapered pipe forming guide hole 101 under this pressure. After forming, the forging hydraulic press is used to lift the upper beam assembly 2, and then the forging operating machine 6 clamps the force transmission beam 301 to lift the middle beam assembly 3, and the forming punch 306 disengages from the tapered pipe forming guide hole 101, and the demolding is completed.

[0076] Compared with the prior art, the present invention designs the forming punch 306 into a columnar portion and a peach-shaped portion, and utilizes the characteristics of the peach-shaped portion of "big head and small body" to facilitate the demoulding process.

[0077] In order to increase the stroke of the forging hydraulic press when the internal space of the forging press is limited, the force transmission beam 301 of the present invention and the forming punch 306 are detachably connected, and the detachable connection structure and connection method are as follows: a vertical pin hole is provided on the force transmission beam 301 and passes through the force transmission beam 301; a connecting vertical pin 304 is provided in the vertical pin hole; a first pin hole is provided at the upper end of the connecting vertical pin 304, and an upper horizontal pin 303 is provided in the first pin hole; a second pin hole is provided at the lower end of the connecting vertical pin 304; a transverse pin hole is provided on the first end of the cylindrical portion, and a transverse pin is provided in the transverse pin hole; a vertical third pin hole is also provided on the first end of the cylindrical portion, the second end of the connecting vertical pin 304 is embedded in the third pin hole, and the second pin hole at the lower end of the connecting vertical pin 304 is aligned with the transverse pin hole; the transverse pin passes through the transverse pin hole and the second pin hole.

[0078] Specifically, if Figure 6As shown, a vertical pin hole is provided at the position where the force transmission crossbeam 301 is connected to the forming punch 306, and the vertical pin hole passes through the force transmission crossbeam 301, and a connecting vertical pin 304 is provided in the vertical pin hole, and the connecting vertical pin 304 is used to connect the force transmission crossbeam 301 and the columnar part of the forming punch 306; a first pin hole is provided at the upper end of the connecting vertical pin 304, and an upper horizontal pin 303 is provided in the first pin hole; a second pin hole is provided at the lower end of the connecting vertical pin 304, and the second pin hole is the same as the first pin hole, and both are horizontal pin holes; a horizontal pin hole is provided on the first end of the columnar part, and a horizontal pin is provided in the horizontal pin hole; it should be noted that In order to detachably connect the connecting pin 304 and the first end of the cylindrical portion of the forming punch 306, a third pin hole is provided on the upper end surface of the first end of the cylindrical portion. Since the shape and diameter of the third pin hole are the same as those of the connecting pin 304, the lower end of the connecting pin 304 can be embedded in the third pin hole. When the lower end of the connecting pin 304 is embedded in the third pin hole, the second pin hole at the lower end of the connecting pin 304 can be aligned with the transverse pin hole on the first end of the cylindrical portion, and the transverse pin is passed through the transverse pin hole and the second pin hole. At this time, a detachable connection is achieved between the force transmission beam 301 and the forming punch 306.

[0079] When it is necessary to disassemble the forming punch 306 from the force transmission beam 301, first pull out the upper cross pin 303 and the lower cross pin 305, then move the connecting vertical pin 304 out of the third pin hole, and the forming punch 306 is separated from the force transmission beam 301, thereby realizing the disassembly of the forming punch 306 from the force transmission beam 301.

[0080] In order to better fix the large-diameter cylindrical forging and its connecting pipe forming part, the forming lower die assembly of the present invention includes a forming lower die 401, a first supporting block 402 and a second supporting block 403, and the first supporting block 402 and the second supporting block 403 are arranged on the outside of the forming lower die 401; the forming lower die 401 is provided with a first hollow annular cavity; the connecting pipe forming part is a connecting pipe boss, and the connecting pipe boss is arranged in the first hollow annular cavity; the first supporting block 402 and the second supporting block 403 are both used to support the boss shoulder of the connecting pipe boss.

[0081] Specifically, the forming lower die assembly of the present invention includes a forming lower die 401, a first support block 402, and a second support block 403. The first support block 402 and the second support block 403 are arranged on the outside of the forming lower die 401. The forming lower die 401 is in the shape of a cylinder, and a first hollow annular cavity is provided inside the cylinder. The space formed by the first hollow annular cavity is used to accommodate the pipe boss; the first support block 402 and the second support block 403 are used to support the shoulder portion of the pipe boss. The upper end faces of the forming lower die 401, the first support block 402, and the second support block 403 of the present invention are all in contact with the large-diameter cylindrical forging, and the lower end faces of the forming lower die 401, the first support block 402, and the second support block 403 are in contact with the supporting lower die assembly. The forming lower die 401, the first support block 402, and the second support block 403 play the role of fixing the large-diameter cylindrical forging and improving the pipe flanging accuracy of the large-diameter cylindrical forging.

[0082] Compared with the prior art, the present invention can achieve firm fixation of the large-diameter cylindrical forging and withstand the downward pressure applied by the forging hydraulic press through the forming lower die 401, the first support block 402 and the second support block 403, thereby ensuring that the pipe forming part of the large-diameter cylindrical forging will not shake when subjected to pressure, thereby ensuring the accuracy of the pipe forming.

[0083] To increase the operating space within the hydraulic forging press, the supporting lower die assembly of the present invention includes a supporting column having a second hollow annular cavity disposed therein. The second hollow annular cavity is disposed below the first hollow annular cavity, with the central axes of the two being aligned. The second hollow annular cavity is used to accommodate the forming punch 306. The hydraulic forging press of the present invention includes a hydraulic press feed platform 405. The hydraulic press feed platform 405 is provided with a third hollow annular cavity. The supporting lower die assembly is disposed within the third hollow annular cavity of the hydraulic press feed platform 405 and extends through the hydraulic press feed platform 405. The hydraulic press feed platform 405 is used to support and move the supporting lower die assembly, the forming lower die 401 set, and the large-diameter cylindrical forging.

[0084] Specifically, the supporting lower die assembly includes a supporting column, a second hollow annular cavity is provided inside the supporting column, and the second hollow annular cavity includes a first cylindrical cavity and a second cylindrical cavity that are interconnected and coaxially arranged; wherein the diameter of the first cylindrical cavity is greater than the diameter of the second cylindrical cavity, and the purpose of arranging the second hollow annular cavity into a first cylindrical cavity and a second cylindrical cavity of unequal diameters is to meet the shape requirements of the pipe nozzle of the large-diameter cylindrical forging. It should be noted that the forging hydraulic press of the present invention includes a hydraulic press feed table 405, on which a third hollow annular cavity is provided, the diameter of the third middle annular cavity is equal to the diameter of the supporting column, and the supporting column is embedded in the third hollow annular cavity; when it is necessary to move the large-diameter cylindrical forging, the supporting lower die assembly and the forming lower die assembly, they can be moved by moving the hydraulic press feed table 405.

[0085] Compared with the prior art, the present invention increases the operating space inside the forging hydraulic press by providing a third hollow annular cavity and embedding the support column in the third hollow annular cavity, thereby solving the problem of limited spatial stroke of the forging hydraulic press. The flanging forming of the pipe of the large-diameter cylindrical forging is realized inside the hydraulic press, and in particular, the flanging forming of the integrated pipe section with pipe of a large-size nuclear power pressure vessel can be realized, thereby eliminating welds, ensuring complete metal streamlines of the forging and uniform deformation of each part, thus meeting the homogenization requirements of ultra-large nuclear power forgings; at the same time, it can also shorten the manufacturing cycle, reduce manufacturing costs, and reduce subsequent in-service inspection work.

[0086] In addition, the design of combining the supporting lower die assembly with the hydraulic press feed table 405 (i.e., embedding the supporting lower die assembly in the hydraulic press feed table 405) fully utilizes the space below the press feed table and further expands the space for forming the flange of the pipe of the diameter cylindrical forging.

[0087] In order to increase the stroke of the forging hydraulic press when the operating space inside the forging press is limited, the pipe forming tooling of the present invention also includes a plurality of stroke increasing blocks 5; the stroke increasing block 5 is arranged on the first end of the cylindrical portion of the forming punch 306; the stroke increasing block 5 is used to increase the stroke of the forming punch 306.

[0088] It should be noted that the hydraulic press feed table 405 is part of the forging hydraulic press, and the hydraulic press feed table 405 is used to move and support large-diameter cylindrical forgings; the forging hydraulic press and the forging manipulator 6 are two independently working devices, and the forging manipulator 6 is used to clamp the force transmission beam 301 of the intermediate beam assembly 3, thereby driving the forming part in the intermediate beam assembly 3 to move in the horizontal direction.

[0089] It should be emphasized that the large-diameter cylindrical forging involved in the above-mentioned pipe forming tool of the present invention is a large-diameter cylindrical blank 1 before forging.

[0090] It should be noted that in the present invention Figures 7a to 7fIn the figure, H refers to the height of the upper crossbeam from the hydraulic feed table during the initial forging, or is called the initial forging height. At the same time, H is also the maximum space height provided by the forging hydraulic press for the pipe forming tooling. △H2 refers to the distance between the upper end face of the large-diameter cylindrical blank 1 and the lower end face of the second vertical beam 203 when the large-diameter cylindrical blank 1 is placed on the supporting lower die assembly and the forming lower die assembly, and the pipe forming part is embedded in the first hollow annular cavity, where △H2>0, to ensure that the large-diameter cylindrical forging can be moved into the forging hydraulic press. △H3 refers to the amount of depression of the forging hydraulic press for the first time. △H4 refers to the amount of depression of the forming punch 306 after adding the first stroke increasing block 5; it should be noted that the depression is numerically equal to the height of the first stroke increasing block 5. After pressing down to a height of ΔH4, the upper crossbeam assembly 2 is lifted, and the middle crossbeam assembly 3 is clamped and lifted using the forging manipulator 6, and the second stroke increasing block 5 is placed again. At this time, the forming punch 306 presses down again by an amount of ΔH5.

[0091] Example 2

[0092] This embodiment provides a method for forming a pipe of a large-diameter cylindrical forging, using the pipe forming tool for a large-diameter cylindrical forging provided in Example 1. The forming method includes the following steps:

[0093] Step 1: prefabricate a large-diameter cylindrical blank 1 with steps, and process a tapered pipe forming guide hole 101 at the pipe forming portion of the large-diameter cylindrical blank 1. After processing, locally heat the pipe forming portion.

[0094] Step 2: Place the large-diameter cylindrical blank 1 on the supporting lower die assembly and the forming lower die assembly, and embed the pipe forming portion into the first hollow annular cavity;

[0095] Step 3: Move the hydraulic press feed table 405 and move the large-diameter cylindrical blank 1 together with the forming lower die assembly and the supporting lower die assembly from the side of the second vertical beam 203 of the upper crossbeam assembly 2 into the forging hydraulic press;

[0096] Step 4: Use the forging manipulator 6 to clamp the middle crossbeam assembly 3 and move it into the large-diameter cylindrical blank 1. Align the upper crossbeam assembly 2 and the middle crossbeam assembly 3. After the forming punch 306 is aligned with the tapered pipe forming guide hole 101, pre-form the pipe. During forming, stop pressing until the stroke limit of the forging hydraulic press is reached, that is, before the upper crossbeam 201 is about to contact the cylinder.

[0097] Step 5: Remove the lower cross pin 305 connected to the forming punch 306 and lift the upper cross beam assembly 2; leave the forming punch 306 and use the forging manipulator 6 to clamp the middle cross beam assembly 3 and lift it;

[0098] Step 6: Install the stroke increasing block 5 above the forming punch 306, lower the middle crossbeam assembly 3 and continue forming the pipe. When the stroke limit of the forging hydraulic press is reached again and the upper crossbeam 201 is about to contact the large-diameter cylindrical blank 1, stop pressing down;

[0099] Step 7: Lift the upper crossbeam assembly 2, and use the forging manipulator 6 to clamp the middle crossbeam assembly 3 and lift it, and place the stroke increasing block 5 again;

[0100] Step 8: Lower the middle crossbeam assembly 3 and align it with the forming lower die assembly, and continue forming the connecting pipe until the connecting pipe is formed.

[0101] It should be noted that a plurality of pipe bosses are provided on the large-diameter cylinder forging, and the remaining pipes are formed using the above-mentioned operation process.

[0102] Example 3

[0103] This embodiment is directed to an integrated nozzle section of a certain type of nuclear reactor pressure vessel. The outer diameter of the large-diameter cylinder forging is 5210 mm, the inner diameter of the cylinder is 3950 mm, and the distance from the nozzle end face to the center of the cylinder is 3520 mm.

[0104] This embodiment utilizes the pipe forming tool provided in Example 1 and the pipe forming method provided in Example 2. The specific pipe forming process is as follows:

[0105] (1) Prefabricate a cylindrical blank with steps, and machine a tapered pipe forming guide hole 101 on the cylindrical blank;

[0106] (2) Local heating of the tube forming area;

[0107] (3) placing the large-diameter cylindrical blank 1 in the forming lower die assembly and the supporting lower die assembly, and aligning the tube forming portion with the forming lower die assembly; that is, embedding the tube forming portion in the first hollow annular cavity;

[0108] (4) Move the hydraulic press feed table 405 and move the large-diameter cylindrical blank 1 together with the forming lower die assembly and the supporting lower die assembly from the side of the second vertical beam 203 of the upper crossbeam assembly 2 into the interior of the forging hydraulic press;

[0109] (5) Using the forging manipulator 6 to clamp the intermediate beam assembly 3 and move it into the interior of the large-diameter cylindrical forging;

[0110] (6) After the forming punch 306 is aligned with the tapered pipe forming guide hole 101, the pipe is pre-formed. When the stroke limit of the forging hydraulic press is reached, that is, before the upper crossbeam 201 contacts the top of the large-diameter cylindrical forging, the pressing is stopped;

[0111] (7) Remove the lower cross pin 305 connected to the forming punch 306, lift the upper cross beam assembly 2, leave the forming punch 306, and use the forging manipulator 6 to clamp the middle cross beam assembly 3 and lift it;

[0112] (8) Place the stroke increasing block 5 on the forming punch 306;

[0113] (9) The middle crossbeam assembly 3 is lowered and aligned, and the pipe is continued to be formed until the stroke limit of the forging hydraulic press is reached, that is, before the upper crossbeam 201 is about to contact the top of the cylinder of the large-diameter cylinder forging, the pressing is stopped;

[0114] (10) Use the forging hydraulic press to lift the upper crossbeam assembly 2, the forging manipulator 6 clamps the middle crossbeam assembly 3 and lifts it, and then place the stroke increasing block 5 again;

[0115] (11) The middle crossbeam assembly 3 is lowered and aligned with the forming lower die assembly, and the forming pipe is continued until the end;

[0116] (12) The remaining pipes are formed using the above-mentioned operation process.

[0117] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A nozzle forming tool for large diameter cylindrical forgings, characterized in that: It includes an upper crossbeam assembly, an intermediate crossbeam assembly, a forming lower die assembly and a supporting lower die assembly; The upper crossbeam assembly is connected to the movable crossbeam of the forging hydraulic press, and the movable crossbeam of the forging hydraulic press can drive the upper crossbeam assembly to move in the upward and downward directions; the upper crossbeam assembly is used to transmit force to the intermediate crossbeam assembly provided below; The upper crossbeam assembly includes an upper crossbeam, a first vertical beam, and a second vertical beam; the height of the first vertical beam is greater than that of the second vertical beam; by adopting a design of unequal heights between the first and second vertical beams, the large-diameter cylindrical forging can be smoothly moved from the side of the second vertical beam into the interior of the forging hydraulic press after being fixed to the forming lower die assembly and the supporting lower die assembly, thereby saving the internal space of the forging hydraulic press; The first vertical beam is mounted on one side of the bottom surface of the upper crossbeam, and the second vertical beam is mounted on the other side; the height difference between the first vertical beam and the second vertical beam is ΔH1; The intermediate crossbeam assembly includes a forming portion, which is used to form the pipe forming portion on the large-diameter cylindrical forging; the intermediate crossbeam assembly is connected to a forging manipulator; the forging manipulator is capable of driving the intermediate crossbeam assembly to move horizontally below the forging hydraulic press and align it vertically with the upper crossbeam assembly; The forming lower die assembly is arranged below the large-diameter cylindrical forging, and is used to withstand the pressure applied by the butt-tube forming part of the forging hydraulic press; the supporting lower die assembly is used to support the forming lower die assembly and the large-diameter cylindrical forging.

2. The nozzle forming tool for large diameter cylindrical forgings according to claim 1, characterized in that: The intermediate crossbeam assembly further includes a force transmission crossbeam and a third vertical beam; The force transmission beam is connected to the forging operation machine, and the forging operation machine is capable of moving the intermediate beam assembly to directly below the upper beam assembly; The third vertical beam is vertically arranged on one side of the upper end surface of the force transmission beam, and the third vertical beam is aligned with the second vertical beam; the height of the third vertical beam is △H1; The forming portion is arranged on the lower end surface of the force transmission beam; the forming portion and the force transmission beam are detachably connected.

3. The nozzle forming tool for large diameter cylindrical forgings according to claim 2, characterized in that: The forming portion includes a forming punch, and the forming punch includes a columnar portion and a peach-shaped portion; the first end of the columnar portion is detachably connected to the force transmission beam, and the second end of the columnar portion is connected to the peach-shaped portion; The diameter of the cylindrical portion is smaller than the maximum diameter of the peach-shaped portion; A conical pipe forming guide hole is provided at the pipe forming portion on the large-diameter cylindrical forging; the forging hydraulic press applies pressure to the forming punch through the upper beam assembly and the lower beam assembly, so that the forming punch performs flanging on the conical pipe forming guide hole.

4. The nozzle forming tool for large diameter cylindrical forgings according to claim 3, characterized in that: A vertical pin hole is provided on the force transmission beam and passes through the force transmission beam; a connecting vertical pin is provided in the vertical pin hole; the upper end of the connecting vertical pin is provided with a first pin hole, and an upper horizontal pin is provided in the first pin hole; the lower end of the connecting vertical pin is provided in the second pin hole; A transverse pin hole is provided on the first end of the cylindrical portion, and a transverse pin is provided in the transverse pin hole; A third vertical pin hole is also provided on the first end of the columnar portion, the second end of the connecting vertical pin is embedded in the third pin hole, and the second pin hole at the lower end of the connecting vertical pin is aligned with the transverse pin hole; the transverse pin passes through the transverse pin hole and the second pin hole.

5. The nozzle forming tool for large diameter cylindrical forgings according to claim 4, characterized in that: The pipe forming portion is a pipe boss; The forming lower die assembly includes a forming lower die, a first supporting block and a second supporting block, wherein the first supporting block and the second supporting block are arranged on the outer side of the forming lower die; The forming lower die is provided with a first hollow annular cavity, and the connecting pipe boss is provided in the first hollow annular cavity; the first supporting block and the second supporting block are both used for supporting the boss shoulder of the connecting pipe boss.

6. The nozzle forming tool for large diameter cylindrical forgings according to claim 5, characterized in that: The supporting lower mold assembly includes a supporting column, wherein a second hollow annular cavity is provided in the supporting column, and the second hollow annular cavity is provided below the first hollow annular cavity and the central axes of the second hollow annular cavity are aligned; The second hollow annular cavity is used to accommodate a forming punch.

7. The nozzle forming tool for large diameter cylindrical forgings according to claim 6, characterized in that: The forging hydraulic press includes a hydraulic press feed table; a third hollow annular cavity is provided in the hydraulic press feed table, and the supporting lower die assembly is provided in the third hollow annular cavity of the hydraulic press feed table and passes through the hydraulic press feed table; the hydraulic press feed table is used to support and move the supporting lower die assembly, the forming lower die assembly and the large-diameter cylindrical forging.

8. The nozzle forming tool for large diameter cylindrical forgings according to claim 7, characterized in that: The pipe forming tool further includes a plurality of stroke increasing blocks; the stroke increasing blocks are provided at the first end of the cylindrical portion of the forming punch; The stroke increasing block is used to increase the stroke of the forming punch.

9. A method for forming a pipe for a large diameter cylindrical forging, characterized in that: The nozzle forming tool for the large-diameter cylindrical forging according to claim 8 is used, and the forming method includes the following steps: Step 1: prefabricate a large-diameter cylinder blank with steps, and process a tapered pipe forming guide hole at the pipe forming portion of the large-diameter cylinder blank. After processing, locally heat the pipe forming portion. Step 2: Place the large-diameter cylindrical blank on the supporting lower die assembly and the forming lower die assembly, and embed the pipe forming portion into the first hollow annular cavity; Step 3: Move the hydraulic press feed table and move the large-diameter cylinder blank together with the forming lower die assembly and the supporting lower die assembly from the side of the second vertical beam of the upper crossbeam assembly into the forging hydraulic press; Step 4: The forging manipulator clamps the middle crossbeam assembly and moves it into the large-diameter cylinder blank. The upper crossbeam assembly and the middle crossbeam assembly are aligned. After the forming punch is aligned with the tapered tube forming guide hole, the tube is pre-formed. When the stroke limit of the forging hydraulic press is reached and the upper crossbeam is about to contact the cylinder, the pressing is stopped. Step 5: Remove the lower cross pin connected to the forming punch and lift the upper cross beam assembly; leave the forming punch, use the forging manipulator to clamp the middle cross beam assembly and lift it; when it is necessary to disassemble the forming punch from the force transmission beam, first pull out the upper and lower cross pins, then remove the connecting vertical pin from the third pin hole, and disengage the forming punch from the force transmission beam, thereby realizing the disassembly of the forming punch and the force transmission beam; Step 6: Install the stroke increasing block above the forming punch, lower the middle crossbeam assembly and continue forming the pipe. When the stroke limit of the forging hydraulic press is reached again and the upper crossbeam is about to contact the cylinder, stop pressing down; Step 7: Lift the upper crossbeam assembly, use the forging manipulator to clamp the middle crossbeam assembly and lift it, and place the stroke increase block again; Step 8: Lower the middle crossbeam assembly and continue forming the pipe until it is finished.

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