CN-117920927-B - High-precision preparation device and method for guide tube of zirconium alloy fuel assembly

Abstract

The invention discloses a high-precision preparation device of a zirconium alloy fuel assembly guide pipe, which comprises a rotary forging assembly, wherein the rotary forging assembly comprises two rotary forging devices which are symmetrically arranged up and down, each rotary forging device comprises a moving plate, a plurality of connecting rods are arranged on each moving plate, a forging hammer is arranged on each connecting rod, a disc chuck seat coaxial with the rotary forging assembly is arranged beside the rotary forging assembly, a polishing cylinder coaxial with the disc chuck seat is arranged on each disc chuck seat, two threaded rods are symmetrically arranged on each polishing cylinder, a round polishing block is respectively arranged at one end of each threaded rod inside each polishing cylinder, and the device also comprises a mandrel which penetrates through the rotary forging assembly and the disc chuck seat and is coaxial with the rotary forging assembly, and a fixing sleeve for clamping and rotating the zirconium alloy pipe. According to the invention, the precise reducing forming and surface treatment of the zirconium alloy fuel assembly guide pipes with different specifications are realized through the angle-adjustable rotary forging device and the round polishing block, and the production efficiency and the yield of the zirconium alloy fuel assembly guide pipes are improved.

Inventors

• YANG ZHIWEI
• LIU CHENGZE
• WU JINPING
• JIA XIN

Assignees

• 西安稀有金属材料研究院有限公司

Dates

Publication Date

20260508

Application Date

20240131

Claims (4)

1. 1. A high-precision preparation device for a zirconium alloy fuel assembly guide tube is characterized by comprising a rotary forging assembly (1), wherein the rotary forging assembly (1) comprises two angle-adjustable rotary forgings which are arranged vertically symmetrically and have the same structure, each angle-adjustable rotary forgings comprises a movable plate (1-1), a plurality of connecting rods (1-2) are arranged on each movable plate (1-1), a forging hammer is arranged on each connecting rod (1-2), a disc chuck (2) coaxial with the rotary forging assembly (1) is arranged beside each rotary forging assembly (1), a polishing cylinder (3) coaxial with the disc chuck (2) is arranged on each disc chuck (2), two threaded rods (4) are symmetrically arranged on each polishing cylinder (3) towards the axis of the polishing cylinder (3), a regular round polishing block (5) is arranged at one end inside each threaded rod (3), the device further comprises a mandrel (1) penetrating through the rotary forging assembly (1) and the disc chuck (2), and three mandrel pins (7) are fixedly connected with the three connecting rods (1-8) through the three mandrel pins (1) and the three mandrel pins (1-8), the three forging hammers are respectively a first forging hammer (1-3), a second forging hammer (1-4) and a 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 quadrangular, the longitudinal section of the third forging hammer (1-5) is triangular, 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 the distance between the bottom surface of the third forging hammer (1-5) and the axis of the rotary forging assembly (1).
2. 2. The high-precision preparation device of the zirconium alloy fuel assembly guide pipe according to claim 1, wherein the threaded rod (4) is movably connected with the polishing cylinder (3), the spring (4-1) is sleeved on the threaded rod (4) inside the polishing cylinder (3), and a groove is formed in one end, facing the rotary forging assembly (1), of the round polishing block (5).
3. 3. A method for preparing a guide tube for a zirconium alloy fuel component with high precision using the apparatus as claimed in any one of claims 1 or 2, comprising the steps of: Adjusting the rotary forging assembly, namely adjusting the positions of a first forging hammer (1-3), a second forging hammer (1-4) and a third forging hammer (1-5) through a connecting rod (1-2) according to the variable diameter specification requirement of a zirconium alloy fuel assembly guide tube, 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 larger than the distance between the bottom surface of the third forging hammer (1-5) and the axis of the rotary forging assembly (1), and the bottom surface of the second forging hammer (1-4) is oblique, so as to obtain an adjusted device of the rotary forging assembly; Step two, the diameter of the zirconium alloy pipe is changed by rotary forging, namely, the zirconium alloy pipe (7) is arranged on a core rod (6) of the device with the adjusted rotary forging assembly obtained in the step one, clamped with a fixed sleeve (8), then the fixed sleeve (8) and a flower disc seat (2) are driven to rotate oppositely, and the zirconium alloy pipe (7) enters the rotary forging assembly (1) to be rotary forged through the fixed sleeve (8), so that the zirconium alloy pipe with a diameter-changing section is obtained; And step three, rounding and polishing the reducing section of the zirconium alloy pipe, namely, entering the reducing section of the zirconium alloy pipe with the reducing section obtained in the step two into a rounding polishing block (5) for rounding and polishing to obtain the high-precision zirconium alloy fuel assembly guide pipe.
4. 4. A method according to claim 3, wherein the dimensional error of the outer diameter of the high precision zirconium alloy fuel component guide pipe of step three is less than 0.05mm.

Description

High-precision preparation device and method for guide tube of zirconium alloy fuel assembly Technical Field The invention belongs to the technical field of metal pipe fitting forming processing, and particularly relates to a high-precision preparation device and method for a zirconium alloy fuel assembly guide pipe. Background The control rod guide pipe for nuclear reactor is a pipe fitting for inserting control rod, burnable poison or neutron source rod and choke plug rod in the fuel assembly skeleton. Has the functions of guiding the movement of the control rod and buffering the falling of the control rod. The guide tube of the conventional nuclear fuel assembly has a structure that the wall thickness is unchanged, and the inner diameter and the outer diameter are changed in a step shape at the same time, such as the guide tube for the AFA2G assembly. The zirconium alloy control rod guide tube has good corrosion resistance and high-temperature strength, and can meet the high-temperature high-pressure nuclear high-radiation environment requirements of a nuclear reactor. The rotary forging cold forming processing technology can efficiently and economically produce the reduced-diameter structural component. A plurality of tapered forging hammers simultaneously and continuously act on a workpiece, and the workpiece rotates and axially moves to be matched with an inner core rod of a pipe so as to realize the purpose of reducing the diameter of a local pipe. However, in order to obtain pipes with different variable diameters, the rotary forging hammers with corresponding specifications are required to be replaced, so that the manufacturing cost is increased, meanwhile, as the zirconium alloy pipe and the forging hammer die are subjected to rapid relative rotation in the rotary forging process to generate friction, the surface roughness of the formed pipe is increased, the surface quality is reduced, and the zirconium pipe is radially forged by the multidirectional forging hammers in the rotary forging process, so that the excircle roundness of the forging hammer clearance pipe can be slightly deviated. In order to obtain better roundness and surface finish, the surface of the pipe after the rotary forging is independently subjected to additional turning, rounding and polishing treatment in the past, but the longer (2 m) fuel assembly guide pipe cannot be subjected to secondary turning due to the limitation of the size of a lathe guide rail. Therefore, in order to solve the existing problems and improve the roundness and surface quality of the products of the guide tube of the zirconium alloy fuel assembly, it is necessary to provide a rotary forging method and an accessory device capable of realizing rotary forging high-precision forming of different reducing specifications by an angle-adjustable forging hammer, and an integrated processing technology for realizing the precision forming and surface treatment of the reducing sections of different specifications in the rotary forging process. Disclosure of Invention The technical problem to be solved by the invention is to provide a high-precision preparation device for the guide tube of the zirconium alloy fuel component aiming at the defects in the prior art. The device forms the rotary forging assembly through two adjustable angle rotary forgings, thereby realizes the partial diameter variation to the partial rotary forging of zirconium alloy pipe of different specifications to realize the diameter variation of different sizes according to reducing specification adjustment its angle, carry out the rule and polish to zirconium alloy pipe reducing part through setting up rule polishing piece, improve the forming accuracy and the surface quality of rotary forging zirconium alloy pipe, improve the production efficiency and the product rate of zirconium alloy fuel assembly stand pipe, realize the rotary forging of zirconium alloy fuel assembly stand pipe, rule, polish integration, and rapid prototyping, finally obtain the high zirconium alloy fuel assembly stand pipe of forming accuracy. In order to solve the technical problems, the technical scheme is that the high-precision preparation device for the zirconium alloy fuel assembly guide tube is characterized by comprising a rotary forging assembly, wherein the rotary forging assembly comprises two rotary forging devices with the same structure and arranged vertically symmetrically, each rotary forging device comprises a movable plate, a plurality of connecting rods are arranged on each movable plate, a forging hammer is arranged on each connecting rod, a disc chuck coaxial with the rotary forging assembly is arranged beside each rotary forging assembly, a polishing barrel coaxial with the disc chuck is arranged on each disc chuck, two threaded rods facing to the axis of the polishing barrel are symmetrically arranged on each polishing barrel, and round polishing blocks are respectively arranged at one ends of the