A high-precision preparation device and method of a zirconium alloy fuel assembly guide tube

Abstract

The application discloses a high-precision preparation device for a zirconium alloy fuel assembly guide tube, which comprises a rotary swaging assembly, the rotary swaging assembly comprises two adjustable-angle rotary swaging devices symmetrically arranged upward and downward, the adjustable-angle rotary swaging device comprises a moving plate, a plurality of connecting rods are arranged on the moving plate, a swaging hammer is arranged on each connecting rod, a chuck seat coaxial with the rotary swaging assembly is arranged on the side of the rotary swaging assembly, a polishing cylinder coaxial with the chuck seat is arranged on the chuck seat, two screw rods are symmetrically installed on the polishing cylinder, a round polishing block is installed at one end of each screw rod in the polishing cylinder, the device further comprises a core rod coaxial with the rotary swaging assembly and the chuck seat, and a fixing sleeve for clamping and rotating the zirconium alloy tube. The adjustable-angle rotary swaging device and the round polishing block are used for realizing accurate diameter change forming and surface treatment of the zirconium alloy fuel assembly guide tubes with different specifications, and the production efficiency and the yield of the zirconium alloy fuel assembly guide tubes are improved.

Description

Technical Field

[0001] This invention belongs to the field of metal pipe forming and processing technology, specifically relating to a high-precision preparation device and method for a zirconium alloy fuel assembly guide tube. Background Technology

[0002] Control rod guide tubes for nuclear reactors are tubular components within the fuel assembly framework that allow the insertion of control rods, combustible poison or neutron source rods, and flow-blocking plugs. They function to guide the movement of control rods and cushion their descent. Commonly used nuclear fuel assembly guide tubes have a constant wall thickness, with both inner and outer diameters varying in a stepped manner, such as the guide tube for the AFA2G assembly. Zirconium alloy control rod guide tubes possess excellent corrosion resistance and high-temperature strength, meeting the requirements of the high-temperature, high-pressure, and high-radiation nuclear reactor environment.

[0003] Rotary forging is a cold forming process that can efficiently and economically produce reduced-diameter structural components. Multiple tapered forging hammers simultaneously and rapidly act on a single workpiece, causing it to rotate and move axially, achieving localized tube diameter reduction in conjunction with an internal mandrel. However, to obtain tubes with different diameter specifications, corresponding rotary forging hammers must be used, increasing manufacturing costs. Furthermore, the rapid relative rotation between the zirconium alloy tube and the forging hammers and dies during rotary forging generates friction, increasing the surface roughness of the formed tube and reducing surface quality. Additionally, the radial forging of the zirconium tube by the multi-directional hammers during rotary forging causes slight deviations in the outer roundness of the tube between the hammers. To achieve better roundness and surface finish, previously, additional turning, rounding, and grinding were required on the surface of the rotary-forged tube. However, for longer (2-meter) fuel assembly guide tubes, secondary turning is not feasible due to limitations in lathe guide rail dimensions.

[0004] Therefore, in order to solve the existing problems and improve the roundness and surface quality of the zirconium alloy fuel assembly guide tube, it is necessary to provide a rotary forging method and accessory device that can achieve high-precision forming of different diameter specifications by rotary forging with an adjustable angle forging hammer, so as to realize an integrated processing technology for precise forming and surface treatment of different diameter sections during rotary forging. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a high-precision manufacturing device for zirconium alloy fuel assembly guide tubes. This device comprises a forging assembly consisting of two adjustable-angle rotary forging machines, enabling partial rotary forging of zirconium alloy tubes of different specifications to achieve partial diameter changes. The angle of the forging machine is adjusted according to the diameter change specifications to achieve different diameter changes. A rounding and grinding block is used to round and grind the diameter-changing portion of the zirconium alloy tube, improving the forming accuracy and surface quality of the rotary forged zirconium alloy tube, increasing the production efficiency and yield of zirconium alloy fuel assembly guide tubes, and achieving integrated rotary forging, rounding, and grinding of zirconium alloy fuel assembly guide tubes, with rapid forming, ultimately obtaining zirconium alloy fuel assembly guide tubes with high forming precision.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a high-precision manufacturing device for a zirconium alloy fuel assembly guide tube, characterized in that the device includes a rotary forging assembly, the rotary forging assembly including two adjustable angle rotary forging machines symmetrically arranged vertically, each adjustable angle rotary forging machine including a moving plate, the moving plate being provided with multiple connecting rods, each connecting rod being provided with a forging hammer, a faceplate seat coaxial with the rotary forging assembly being provided beside the rotary forging assembly, a grinding cylinder coaxial with the faceplate seat being provided on the faceplate seat, two threaded rods symmetrically installed on the grinding cylinder facing the axis of the grinding cylinder, each of the two threaded rods having a round grinding block installed at one end inside the grinding cylinder, the device also including a mandrel passing through the rotary forging assembly and the faceplate seat and coaxial with it, and a fixing sleeve for clamping and rotating the zirconium alloy tube.

[0007] The high-precision manufacturing device for a zirconium alloy fuel assembly guide tube is characterized in that the connecting rod is movably connected to the moving plate, the number of the connecting rods is three, and the number of forging hammers is three. The lower parts of the three forging hammers are connected by pins. The three forging hammers are: a first forging hammer, a second forging hammer, and a third forging hammer. The longitudinal section of the first forging hammer is rectangular, the longitudinal section of the second forging hammer is quadrilateral, and the longitudinal section of the third forging hammer is triangular. The distance between the bottom surface of the first forging hammer and the axis of the rotary forging assembly is greater than the distance between the bottom surface of the third forging hammer and the axis of the rotary forging assembly.

[0008] The high-precision manufacturing device for the zirconium alloy fuel assembly guide tube described above is characterized in that the threaded rod is movably connected to the grinding cylinder, and a spring is fitted on the threaded rod inside the grinding cylinder, and the circular grinding block has a bevel at the end facing the rotary forging assembly.

[0009] In addition, the present invention also provides a high-precision manufacturing method for a zirconium alloy fuel assembly guide tube, characterized in that the method includes the following steps:

[0010] Step 1: Adjustment of the rotary forging assembly: According to the variable diameter specifications of the zirconium alloy fuel assembly guide tube, adjust the positions of the first forging hammer, the second forging hammer and the third forging hammer through the connecting rod, so that the distance between the bottom surface of the first forging hammer and the axis of the rotary forging assembly is greater than the distance between the bottom surface of the third forging hammer and the axis of the rotary forging assembly, and make the bottom surface of the second forging hammer be an oblique line, thus obtaining the adjusted device of the rotary forging assembly.

[0011] Step 2, Rotary forging and diameter reduction of zirconium alloy tube: Install the zirconium alloy tube on the mandrel of the device after adjustment of the rotary forging assembly obtained in Step 1, and clamp it with the fixed sleeve. Then drive the fixed sleeve and the face plate to rotate in opposite directions. Then, through the fixed sleeve, the zirconium alloy tube enters the rotary forging assembly for rotary forging to obtain a zirconium alloy tube with a diameter reduction section.

[0012] Step 3: Rounding and grinding of the variable diameter section of the zirconium alloy tube: The variable diameter section of the zirconium alloy tube obtained in Step 2 is fed into the rounding and grinding block for rounding and grinding to obtain a high-precision zirconium alloy fuel assembly guide tube.

[0013] This invention processes a forging hammer according to the variable diameter specifications of the zirconium alloy fuel assembly guide tube. The forging hammer is installed on a rotary forging equipment, and a rounding grinding cylinder is fixed to the faceplate seat of the rotary forging equipment with bolts. Then, the zirconium alloy tube is fixed on the fixed sleeve to ensure that the zirconium alloy tube is stably installed on the main axis. Then, a suitable rotary forging forming process is selected, and the faceplate seat is driven by a motor to realize the rotary forging forming of the zirconium alloy variable diameter tube. The formed variable diameter section then enters the rounding grinding cylinder fixed on the rotating body to achieve rounding and surface treatment. It rotates with the rotation of the faceplate seat during the rotary forging process. The grinding block fixed on the grinding cylinder by the threaded rod contacts the surface of the tube. During the rotation process, the rounding and surface grinding of the zirconium alloy variable diameter section are realized, improving the surface quality of the zirconium alloy guide tube.

[0014] The above method is characterized in that the dimensional error of the outer diameter of the high-precision zirconium alloy fuel assembly guide tube in step three is less than 0.05 mm.

[0015] In this invention, the feed rate of the zirconium alloy tube for rotary forging is 10 mm / min to 15 mm / min, the rotation speed is 500 r / min to 600 r / min, the rotation speed of the face plate is also 500 r / min to 600 r / min and opposite to the rotation direction of the zirconium alloy tube, and the particle size of the surface of the round grinding block is 600 mesh to 1000 mesh.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. This invention uses two identical adjustable-angle rotary forging machines to form a rotary forging assembly, enabling partial rotary forging of zirconium alloy tubes of different specifications to achieve partial diameter changes. The angle of the forging machine is adjusted according to the diameter change specifications to achieve different diameter changes. By setting a rounding and grinding block to round and grind the diameter change portion of the zirconium alloy tube, the forming accuracy and surface quality of the rotary forged zirconium alloy tube are improved. The zirconium alloy tube is then used to prepare a zirconium alloy fuel assembly guide tube, realizing the integration of rotary forging, rounding, and grinding of the zirconium alloy fuel assembly guide tube, and enabling rapid forming. This improves the production efficiency and yield of the zirconium alloy fuel assembly guide tube, ultimately obtaining a zirconium alloy fuel assembly guide tube with high forming accuracy.

[0018] 2. The present invention sets up a pattern plate seat, which drives the grinding cylinder to rotate, thereby driving the rounding grinding block set in the grinding cylinder to rotate, realizing rounding and grinding. Moreover, the rotation direction of the pattern plate seat is opposite to the rotation direction of the zirconium alloy tube, which improves the rounding and grinding effect.

[0019] 3. The present invention uses three connecting rods to fix the first forging hammer, the second forging hammer and the third forging hammer respectively. The angle adjustment of the three forging hammers is achieved by controlling the movement of the connecting rods. By adjusting the angle between the forging hammers, the guide tubes of zirconium alloy fuel assembly with different diameter specifications can be forged and have a diameter change. The lower parts of the three forging hammers are connected by pins, so that the three forging hammers form a whole and the lower plane meets the diameter change requirements during forging.

[0020] 4. This invention controls the longitudinal section of the first forging hammer to be rectangular, and the distance between the bottom surface of the first forging hammer and the axis of the rotary forging assembly is greater than the distance between the bottom surface of the third forging hammer and the axis of the rotary forging assembly. This ensures the rotary forging of both the non-diameter and diameter-changing sections of the zirconium alloy fuel assembly guide tube. By controlling the longitudinal section of the second forging hammer to be quadrilateral, and because the lower parts of the three forging hammers are connected by pins, the second forging hammer forms an inclined surface between the first and third forging hammers, providing an inclined surface for the diameter-changing section. Furthermore, by controlling the longitudinal section of the third forging hammer to be triangular, a position is reserved for the second forging hammer, ensuring that the second forging hammer can be tilted at any angle to achieve rotary forging diameter changes of different sizes.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a cross-sectional schematic diagram of the high-precision fabrication device for the zirconium alloy fuel assembly guide tube of the present invention.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1—Rotary forging assembly; 1-1—Moving plate; 1-2—Connecting rod;

[0025] 1-3—First forging hammer; 1-4—Second forging hammer; 1-5—Third forging hammer;

[0026] 2—Grinding plate holder; 3—Grinding cylinder; 4—Threaded rod;

[0027] 4-1—Spring; 5—Grinding block for rounding; 6—Mandrel;

[0028] 7—Zirconium alloy tube; 8—Fixing sleeve. Detailed Implementation

[0029] A high-precision fabrication apparatus for a zirconium alloy fuel assembly guide tube of the present invention is described in detail through Example 1.

[0030] Example 1

[0031] like Figure 1 As shown, the high-precision manufacturing device for the zirconium alloy fuel assembly guide tube in this embodiment includes a rotary forging assembly 1. The rotary forging assembly 1 includes two adjustable-angle rotary forging machines with identical structures arranged symmetrically on top and bottom. Each adjustable-angle rotary forging machine includes a moving plate 1-1. Multiple connecting rods 1-2 are provided on the moving plate 1-1. Each connecting rod 1-2 is provided with a forging hammer. A faceplate seat 2 coaxial with the rotary forging assembly 1 is provided on the side of the rotary forging assembly 1. A grinding cylinder 3 coaxial with the faceplate seat 2 is provided on the faceplate seat 2. Two threaded rods 4 facing the axis of the grinding cylinder 3 are symmetrically installed on the grinding cylinder 3. A circular grinding block 5 is installed at one end of each of the two threaded rods 4 inside the grinding cylinder 3. The device also includes a mandrel 6 that passes through the rotary forging assembly 1 and the faceplate seat 2 and is coaxial with the faceplate seat 2, and a fixing sleeve 8 for clamping and rotating the zirconium alloy tube 7.

[0032] It should be noted that the rotary forging assembly 1, composed of two adjustable-angle rotary forging machines, enables partial rotary forging of zirconium alloy tubes 7 of different specifications, thereby achieving partial diameter change. The angle of the rotary forging machine is adjusted according to the diameter change specification to achieve different diameter changes, thus preparing the zirconium alloy tube 7 into a zirconium alloy fuel assembly guide tube. By setting a rounding and grinding block 5, the diameter change part of the zirconium alloy tube 7 is rounded and ground, improving the forming accuracy and surface quality of the rotary forged zirconium alloy tube 7, increasing the production efficiency and yield of the zirconium alloy fuel assembly guide tube, realizing the integration of rotary forging, rounding, and grinding of the zirconium alloy fuel assembly guide tube, and achieving rapid forming, ultimately obtaining a zirconium alloy fuel assembly guide tube with high forming accuracy.

[0033] It should be noted that by setting the movable plate 1-1 to fix the connecting rod 1-2 and the forging hammer, and by moving the movable plate 1-1 toward the mandrel 6 to achieve the downward pressing action, the rotary forging is realized. By setting the connecting rod 1-2 to fix the forging hammer, the rotary forging diameter change is realized.

[0034] It should be noted that by setting the flower plate seat 2, the flower plate seat 2 drives the grinding cylinder 3 to rotate, thereby driving the rounding grinding block 5 set in the grinding cylinder 3 to rotate, realizing rounding and grinding. Moreover, the rotation direction of the flower plate seat 2 is opposite to the rotation direction of the zirconium alloy tube 7, which improves the rounding and grinding effect.

[0035] It should be noted that by setting the mandrel 6 to support the inside of the zirconium alloy tube 7, the effect of rotary forging is ensured. By setting the fixing sleeve 8 to rotate and feed the zirconium alloy tube 7, the smooth progress of rotary forging, rounding, and grinding is ensured.

[0036] In this embodiment, the connecting rods 1-2 are movably connected to the movable plate 1-1. There are three connecting rods 1-2 and three forging hammers. The lower parts of the three forging hammers are connected by pins. The three forging hammers are: the first forging hammer 1-3, the second forging hammer 1-4, and the third forging hammer 1-5. The longitudinal section of the first forging hammer 1-3 is rectangular, the longitudinal section of the second forging hammer 1-4 is quadrilateral, and the longitudinal section of the third forging hammer 1-5 is triangular. The distance between the bottom surface of the first forging hammer 1-3 and the axis of the rotary forging assembly 1 is greater than the distance between the bottom surface of the third forging hammer 1-5 and the axis of the rotary forging assembly 1. Three connecting rods 1-2 are used to fix the first forging hammer 1-3, the second forging hammer 1-4, and the third forging hammer 1-5 respectively. The angle of the three forging hammers is adjusted by controlling the movement of the connecting rods 1-2. By adjusting the angle between the forging hammers, the guide tubes of zirconium alloy fuel assembly with different diameter specifications can be rotary forged and have different diameters. The lower parts of the three forging hammers are connected by pins, so that the three forging hammers form a whole and the lower plane meets the diameter change requirements during rotary forging. By control, the longitudinal section of the first forging hammer 1-3 is rectangular, and the distance between the bottom surface of the first forging hammer 1-3 and the axis of the rotary forging assembly 1 is greater than that of the third forging hammer 1-5. The distance between the bottom surface of forging hammer 1-5 and the axis of rotary forging assembly 1 ensures the rotary forging of both the non-diameter and diameter-changing sections of the zirconium alloy fuel assembly guide tube. By controlling the longitudinal section of the second forging hammer 1-4 to be quadrilateral, and because the lower parts of the three forging hammers are connected by pins, the second forging hammer 1-4 forms an inclined surface between the first forging hammer 1-3 and the third hammer, providing an inclined surface for the diameter-changing section. Furthermore, by controlling the longitudinal section of the third forging hammer 1-5 to be triangular, a position is reserved for the second forging hammer 1-4, ensuring that the second forging hammer 1-4 can be tilted at any angle to achieve rotary forging diameter changes of different sizes.

[0037] In this embodiment, the threaded rod 4 is movably connected to the grinding cylinder 3, and a spring 4-1 is fitted on the threaded rod 4 inside the grinding cylinder 3. The end of the circular grinding block 5 facing the rotary forging assembly 1 has a bevel. By movably connecting the threaded rod 4 to the grinding cylinder 3, and fitting the spring 4-1 on the threaded rod 4 inside the grinding cylinder 3, the spring 4-1 always applies pressure to the circular grinding block 5, causing the circular grinding block 5 to move towards the axis of the grinding cylinder 3. The distance between the two circular grinding blocks 5 is less than the outer diameter of the variable diameter section of the zirconium alloy tube 7, thereby achieving circular grinding. At the same time, the bevel at the end of the circular grinding block 5 facing the rotary forging assembly 1 is to allow the variable diameter section of the zirconium alloy tube 7 to smoothly enter between the two smaller circular grinding blocks 5.

[0038] It should be noted that the pressure of the round grinding block 5 in contact with the surface of the variable diameter section of the zirconium alloy tube 7 is adjusted by the compression of the threaded rod 4 and the spring 4-1.

[0039] The high-precision manufacturing method of a zirconium alloy fuel assembly guide tube of the present invention is described in detail through Examples 2 to 4.

[0040] Example 2

[0041] In this embodiment, a zirconium alloy tube with an outer diameter of 22mm, a wall thickness of 1.5mm, and a length of 1000mm is transformed at one end to an outer diameter of 18mm, with a diameter transformation slope of 45°.

[0042] This embodiment includes the following steps:

[0043] Step 1: Adjustment of the rotary forging assembly: According to the diameter specification requirements of the zirconium alloy fuel assembly guide tube, adjust the positions of the first forging hammer 1-3, the second forging hammer 1-4, and the third forging hammer 1-5 through the connecting rod 1-2, so that the distance between the bottom surface of the first forging hammer 1-3 and the axis of the rotary forging assembly 1 is 11mm, the distance between the bottom surface of the third forging hammer 1-5 and the axis of the rotary forging assembly 1 is 9mm, and the bottom surface of the second forging hammer 1-4 is an oblique line with an angle of 45° with the axis of the rotary forging assembly 1, thus obtaining the adjusted rotary forging assembly device;

[0044] Step 2, Rotary forging and diameter reduction of zirconium alloy tube: Install zirconium alloy tube 7 on the mandrel 6 of the device after adjustment of the rotary forging assembly obtained in Step 1, and clamp it with the fixed sleeve 8. Then drive the fixed sleeve 8 and the face plate seat 2 to rotate in opposite directions. Then, through the fixed sleeve 8, the zirconium alloy tube 7 enters the rotary forging assembly 1 for rotary forging. The feed rate is 10 mm / min and the rotation speed is 500 r / min, to obtain a zirconium alloy tube with a diameter reduction section.

[0045] Step 3: Rounding and grinding of the variable diameter section of the zirconium alloy tube: The variable diameter section of the zirconium alloy tube obtained in Step 2 is fed into a rounding and grinding block 5 with a surface grit of 600 mesh for rounding and grinding to obtain a high-precision zirconium alloy fuel assembly guide tube.

[0046] Testing revealed that the outer diameter error of the high-precision zirconium alloy fuel assembly guide tube in this embodiment is less than 0.05 mm, and the surface is smooth.

[0047] Example 3

[0048] In this embodiment, one end of a zirconium alloy tube 7 with an outer diameter of 28 mm, a wall thickness of 1.5 mm, and a length of 2000 mm is changed to an outer diameter of 24 mm with a change slope of 35°.

[0049] This embodiment includes the following steps:

[0050] Step 1: Adjustment of the rotary forging assembly: According to the diameter specification requirements of the zirconium alloy fuel assembly guide tube, adjust the positions of the first forging hammer 1-3, the second forging hammer 1-4, and the third forging hammer 1-5 through the connecting rod 1-2 so that the distance between the bottom surface of the first forging hammer 1-3 and the axis of the rotary forging assembly 1 is 14mm, the distance between the bottom surface of the third forging hammer 1-5 and the axis of the rotary forging assembly 1 is 12mm, and the bottom surface of the second forging hammer 1-4 is an oblique line with an angle of 35° with the axis of the rotary forging assembly 1, thus obtaining the adjusted rotary forging assembly device;

[0051] Step 2, Rotary forging and diameter reduction of zirconium alloy tube: Install zirconium alloy tube 7 on the mandrel 6 of the device after adjustment of the rotary forging assembly obtained in Step 1, and clamp it with the fixed sleeve 8. Then drive the fixed sleeve 8 and the face plate seat 2 to rotate in opposite directions. Then, through the fixed sleeve 8, the zirconium alloy tube 7 enters the rotary forging assembly 1 for rotary forging. The feed rate is 12 mm / min and the rotation speed is 550 r / min, to obtain a zirconium alloy tube with a diameter reduction section.

[0052] Step 3: Rounding and grinding of the variable diameter section of the zirconium alloy tube: The variable diameter section of the zirconium alloy tube obtained in Step 2 is fed into a rounding and grinding block 5 with a surface grit of 800 mesh for rounding and grinding to obtain a high-precision zirconium alloy fuel assembly guide tube.

[0053] Testing revealed that the outer diameter error of the high-precision zirconium alloy fuel assembly guide tube in this embodiment is less than 0.05 mm, and the surface is smooth.

[0054] Example 4

[0055] In this embodiment, one end of a zirconium alloy tube 7 with an outer diameter of 12mm, a wall thickness of 1mm, and a length of 1500mm is changed to an outer diameter of 8mm with a change slope of 55°.

[0056] This embodiment includes the following steps:

[0057] Step 1: Adjustment of the rotary forging assembly: According to the diameter specification requirements of the zirconium alloy fuel assembly guide tube, adjust the positions of the first forging hammer 1-3, the second forging hammer 1-4, and the third forging hammer 1-5 through the connecting rod 1-2 so that the distance between the bottom surface of the first forging hammer 1-3 and the axis of the rotary forging assembly 1 is 6mm, the distance between the bottom surface of the third forging hammer 1-5 and the axis of the rotary forging assembly 1 is 4mm, and the bottom surface of the second forging hammer 1-4 is made to be an oblique line with an angle of 55° with the axis of the rotary forging assembly 1, thus obtaining the adjusted rotary forging assembly device;

[0058] Step 2, Rotary forging and diameter reduction of zirconium alloy tube: Install zirconium alloy tube 7 on the mandrel 6 of the device after adjustment of the rotary forging assembly obtained in Step 1, and clamp it with the fixed sleeve 8. Then drive the fixed sleeve 8 and the face plate seat 2 to rotate in opposite directions. Then, through the fixed sleeve 8, the zirconium alloy tube 7 enters the rotary forging assembly 1 for rotary forging. The feed rate is 15 mm / min and the rotation speed is 600 r / min, to obtain a zirconium alloy tube with a diameter reduction section.

[0059] Step 3: Rounding and grinding of the variable diameter section of the zirconium alloy tube: The variable diameter section of the zirconium alloy tube obtained in Step 2 is fed into a rounding and grinding block 5 with a surface grit of 1000 mesh for rounding and grinding to obtain a high-precision zirconium alloy fuel assembly guide tube.

[0060] Testing revealed that the outer diameter error of the high-precision zirconium alloy fuel assembly guide tube in this embodiment is less than 0.05 mm, and the surface is smooth.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A high-precision fabrication apparatus for a zirconium alloy fuel assembly guide tube, characterized in that, The device includes a rotary forging assembly (1), which includes two identical adjustable-angle rotary forging heads arranged symmetrically on top and bottom. Each adjustable-angle rotary forging head includes a movable plate (1-1) with multiple connecting rods (1-2) on the movable plate (1-1). Each connecting rod (1-2) is equipped with a forging hammer. A faceplate seat (2) coaxial with the rotary forging assembly (1) is arranged on the side of the rotary forging assembly (1). A grinding cylinder (3) coaxial with the faceplate seat (2) is arranged on the faceplate seat (2). Two threaded rods (4) facing the axis of the grinding cylinder (3) are symmetrically installed on the grinding cylinder (3). A round grinding block (5) is installed at one end of each of the two threaded rods (4) inside the grinding cylinder (3). The device also includes a device that passes through the rotary forging assembly (1) and the faceplate. The mandrel (6) is coaxial with the seat (2), and the fixing sleeve (8) is used to clamp and rotate the zirconium alloy tube (7); the connecting rod (1-2) is movably connected to the moving plate (1-1), the number of the connecting rod (1-2) is three, and the number of forging hammers is three. The lower parts of the three forging hammers are connected by pins. The three forging hammers are: the first forging hammer (1-3), the second forging hammer (1-4) and the third forging hammer (1-5). The longitudinal section of the first forging hammer (1-3) is rectangular, the longitudinal section of the second forging hammer (1-4) is quadrilateral, and the longitudinal section of the third forging hammer (1-5) is triangular. The distance between the bottom surface of the first forging hammer (1-3) and the axis of the rotary forging assembly (1) is greater than the distance between the bottom surface of the third forging hammer (1-5) and the axis of the rotary forging assembly (1).

2. The high-precision fabrication apparatus for a zirconium alloy fuel assembly guide tube according to claim 1, characterized in that, The threaded rod (4) is movably connected to the grinding cylinder (3), and a spring (4-1) is fitted on the threaded rod (4) inside the grinding cylinder (3). The circular grinding block (5) has a bevel at one end facing the rotary forging assembly (1).

3. A method for high-precision fabrication of zirconium alloy fuel assembly guide tubes using the apparatus described in any one of claims 1 or 2, characterized in that, The method includes the following steps: Step 1: Adjustment of the rotary forging assembly: According to the diameter specification requirements of the zirconium alloy fuel assembly guide tube, adjust the positions of the first forging hammer (1-3), the second forging hammer (1-4), and the third forging hammer (1-5) through the connecting rod (1-2) so that the distance between the bottom surface of the first forging hammer (1-3) and the axis of the rotary forging assembly (1) is greater than the distance between the bottom surface of the third forging hammer (1-5) and the axis of the rotary forging assembly (1), and make the bottom surface of the second forging hammer (1-4) an oblique line, thus obtaining the device after the adjustment of the rotary forging assembly; Step 2, forging and reducing the diameter of the zirconium alloy tube: Install the zirconium alloy tube (7) on the mandrel (6) of the device after the forging assembly is adjusted in Step 1, and clamp it with the fixed sleeve (8). Then drive the fixed sleeve (8) and the flower plate seat (2) to rotate in opposite directions. Then, through the fixed sleeve (8), the zirconium alloy tube (7) enters the forging assembly (1) for forging to obtain a zirconium alloy tube with a variable diameter section. Step 3: Rounding and grinding of the variable diameter section of the zirconium alloy tube: The variable diameter section of the zirconium alloy tube obtained in Step 2 is put into the rounding and grinding block (5) for rounding and grinding to obtain a high-precision zirconium alloy fuel assembly guide tube.

4. The method according to claim 3, characterized in that, The dimensional error of the outer diameter of the high-precision zirconium alloy fuel assembly guide tube described in step three is less than 0.05 mm.

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