JP3795111B2 - Water jet peening equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water jet peening apparatus that improves a tensile residual stress existing in a metal material and prevents stress corrosion cracking by injecting a liquid jet onto the metal member, and in particular, penetrates the end plate of the pressure vessel. The present invention relates to a water jet peening apparatus for improving a stress state of a welded portion surface of a pipe welded and fixed to an inner surface of a pressure vessel while being maintained in the atmosphere.
[0002]
[Prior art]
As a method for alleviating residual stress in a welded part or the like that causes stress corrosion cracking, there is a technique disclosed in Japanese Patent Application Laid-Open No. 62-63614.
[0003]
This is because a high-pressure water shot peening device having a rotating nozzle that injects a high-pressure liquid jet is inserted into a pipe such as a heat exchanger that is an object of residual stress improvement, and the axial dynamic pressure energy (jet jet) of the jet itself is inserted. The tensile residual stress originally present in the pipe is softened to the compressive residual stress by peening the inner surface of the pipe with the axial dynamic pressure energy).
[0004]
In addition, the technique disclosed in Japanese Patent Laid-Open No. 6-62408 is a technique in which water is filled in a pressure vessel and a high-pressure jet is jetted in the water to a welded portion of a pipe that is welded and fixed to a lower mirror portion of the pressure vessel. By doing so, cavitation bubbles are generated to improve the surface stress state.
[0005]
In this proposal, with the water inside the pressure vessel, the device is set at a predetermined position using the internal structure of the pressure vessel and the through pipe, and the target welded part is rotated by rotating the nozzle around the pipe. To improve the stress.
[0006]
[Problems to be solved by the invention]
The prior art disclosed in JP-A-62-63614 is considered to be an effective means for improving the residual stress on the inner surface of a pipe such as a heat exchanger by utilizing the axial dynamic pressure of a water jet in the atmosphere. Since this part has a simple welded shape on the inner surface of the pipe, it is considered that the water recovery and apparatus used can be implemented relatively easily.
[0007]
Further, the prior art disclosed in Japanese Patent Application Laid-Open No. 5-78738 is capable of installing the apparatus in water and using a structure inside the pressure vessel, so that there is no need to collect water and water that generates cavitation bubbles at the same time. There is no need to pay attention to creating an environment.
[0008]
FIG. 9 is a cross-sectional view of the end plate portion of the pressure vessel, and FIG. 10 is an enlarged view of a main part thereof.
[0009]
A large number of pipes 102 are provided which penetrate through the end plate 101 of the pressure vessel held in the atmosphere and are fixed to the inner surface of the pressure vessel by welding. As shown in FIG. The residual stress of the welded portion produces a high tensile residual stress portion 104 including the weld metal 103 and the vicinity thereof.
[0010]
When improving the residual stress of such a welded part, it is a welded part between the outer surface of the pipe and the pressure vessel end plate, and the welded part has a three-dimensional shape in a pipe fixed at an inclination to the end plate. In addition, it is necessary to perform complicated position control of the injection nozzle, and when performing peening in the atmosphere, particularly in the case of a reactor pressure vessel, it is necessary to recover water in order to prevent the spread of contamination.
[0011]
Further, in order to improve the residual stress by generating cavitation bubbles in water, it is necessary to collect water in the same manner as described above at the same time as forming a water environment in the part.
An object of this invention is to provide the water jet peening apparatus which can improve the residual stress of the welding part of the piping fixed by welding to the inner surface of a pressure vessel.
[0012]
[Means for Solving the Problems]
The purpose of the above is to hold a pipe having a welded part held in the atmosphere, and to generate cavitation bubbles in the water by jetting high-pressure water, and to cause the cavitation bubbles to collide with the surface of the welded part. A nozzle for improving the state, and a pool forming means for forming a pool for holding the weld and the nozzle in water;
Rotating means having a rotational drive shaft for rotating the nozzle along the periphery of the welded portion, a positioning head attached to the upper end of the rotational drive shaft, and a positioning lug provided on the outer surface of the pool forming means And a positioning means for inserting the positioning head into the pipe and inserting the positioning lug into another pipe to position the pool forming means .
[0013]
Further, the first means is achieved by a second means provided with a vertically moving means for moving the nozzle up and down along the axial direction of the pipe .
[0014]
Further, in the first or second means, it is achieved by a third means provided with a moving means for moving a carriage on which the nozzle, the pool forming means, the positioning means and the rotating means are mounted .
[0015]
Further, in any one of the first to third means, the pipe is welded to the inner surface of the pressure vessel, and a portion of the pool forming means facing the inner surface of the pressure vessel has a shape matching the curvature of the pressure vessel. This is achieved by the fourth means.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The outline of the present invention will be described first.
[0018]
The carriage on which the apparatus is mounted is moved to the bottom of the pipe, the positioning apparatus is inserted into the pipe, the center of the apparatus is aligned, and the cover is pressed so that the edge thereof is in close contact with the inner surface of the pressure vessel. At this time, a packing having a shape matching the curvature of the pressure vessel is provided at the upper end portion of the cover, and a sealing space is formed by the cover, the rotation plate, and the inner surface of the pressure vessel by providing a packing between the rotation plate and the cover. be able to.
[0019]
In this state, the cover is filled with water to form a pool, a high-pressure jet liquid is ejected from the ejection nozzle to generate cavitation bubbles, the rotation drive device of the rotation plate is operated to rotate the rotation plate, By operating the axial drive device of the rotating plate to move the rotating plate in the axial direction, the injection nozzle fixed to the rotating plate can be rotated around the pipe and moved in the axial direction of the pipe.
[0020]
In addition, by controlling the position of each drive motor by the control device, the injection nozzle can be uniformly opposed to the welded portion of the pressure vessel and the piping, and stable cavitation bubbles can collide with the welded portion. And the residual stress on the surface of the welded portion can be improved.
[0021]
At this time, water and air bubbles ejected from the ejection nozzle are guided to the outside through a discharge port provided in the vicinity of the upper end of the cover and are easily recovered.
[0022]
Also, by inserting protrusions attached to the outer surface of the cover into the adjacent piping, the orientation of the cover is always kept constant even if the rotating plate rotates and moves, so that the sealing surface with the pressure vessel is displaced. The pool can be formed stably.
Hereinafter, it demonstrates concretely, referring drawings.
[0023]
FIG. 1 is a cross-sectional view showing a state in which a water jet peening apparatus according to the present invention is installed in a pipe 102 that is welded and fixed to an end plate 101 of a pressure vessel.
[0024]
2 is a cross-sectional view taken along line AA of FIG. 1, FIG. 3 is a cross-sectional view taken along line BB of FIG. 1, and FIG. 4 is a cross-sectional view taken along line CC of FIG.
[0025]
In FIG. 1, a positioning head 11 is rotatably fixed to the upper end of the rotary drive shaft 12 via a bearing 12a, and the lower end portion is fixed to be freely rotatable through a lifting carriage 13 via a bearing 12b. The tip is connected to a rotary drive motor 15 via a coupling 14.
[0026]
Further, the central portion of the rotary drive shaft 12 has a spline structure (see FIG. 2), is installed through the rotary cylinder 17 and is movable in the axial direction with a spline nut 17a fixed inside the rotary cylinder 17. Is engaged. A rotating plate 16 is fixed to the upper end of the rotating cylinder 17, and the rotating plate 16 can be rotated via the rotation driving shaft 12, the spline nut 17 a and the rotating cylinder 17 by the rotation of the rotation driving motor 15. .
[0027]
On the other hand, an elevating flange 18 is rotatably fixed to the lower end portion of the rotary cylinder 17 via a bearing 18a, and a nut 19a engaged with the elevating screw shaft 19 is fixed to the elevating flange 18. A lower end portion of the elevating screw shaft 19 is rotatably fixed through the elevating carriage 13 through a bearing 19b, and an elevating shaft rotating gear 20 is attached to the tip.
[0028]
The transmission gear (A) 21a is rotatably fixed via a rotation drive shaft 12 and a bearing 21d penetrating in the center thereof, and the transmission gear (C) via a lifting shaft rotation gear 20 and a transmission gear (B) 21b. It is engaged with a lift drive motor 22 to which 21c is attached (see FIGS. 3 and 4).
[0029]
With this configuration, the elevating drive shaft 19 is rotated by the rotation of the elevating drive motor 22 through the transmission gears (C) 21c, (B) 21b, (A) 21a and the elevating shaft rotating gear 20, and the nut 19a engaged therewith. Can be raised and lowered, and further, the rotary cylinder 17 and the rotary plate 16 can be raised and lowered.
[0030]
Since the bearing is arranged between the rotation drive system and the elevation drive system, each operation can be performed without being influenced by each other.
[0031]
The cover 23 has a rotating plate 16 disposed therein, and a packing 24 adapted to the inner shape of the end plate 101 is attached to the upper end. A drain outlet 23 a is provided in the vicinity of the upper end portion of the cover 23 so that the drain hose 25 can be connected thereto.
[0032]
The front end of the air cylinder 26 fixed to the elevating carriage 13 is fixed so as to be movable in the circumferential direction of the cover 23 and a flange 23 b provided on the outer periphery of the cover 23. A cover positioning lug 27 is provided on the outer surface of the cover 23 so that the cover 23 can be inserted into the adjacent pipe and the orientation of the cover 23 can be fixed.
[0033]
The nozzle 28 penetrates the rotating plate 16, and the tip thereof is fixed toward the welded portion between the pipe 102 and the end plate 101, and the other end is connected to a high-pressure hose 29.
[0034]
All of the above devices are fixed to the lifting carriage 13, and the lifting carriage 13 moves on the rail 31 fixed to the moving carriage 32 via the linear guide 30. Further, a nut 33 is attached to the lift carriage 13 and meshes with a carriage lift screw shaft 34 fixed to the movable carriage 32.
[0035]
The carriage raising / lowering screw shaft 34 is connected to the carriage raising / lowering drive motor 36 via the timing belt 35, and the carriage raising / lowering screw shaft 34 is rotated by the carriage raising / lowering driving shaft 36 to move the elevation carriage 13 up and down. be able to. A caster 37 is attached to the movable carriage 32.
[0036]
On the other hand, packings 16a and 16b are attached between the rotary plate 16, the cover 23, and the rotary drive shaft 12, and the water stored in the cover 23 is sealed to form a water pool.
[0037]
Each drive motor and air hose are connected to a control panel 51 installed outside, and the high-pressure hose 29 is connected to a high-pressure pump 52 installed outside (see FIG. 5).
[0038]
Next, an operation procedure of the water jet peening apparatus configured as described above will be described.
[0039]
First, as shown in FIG. 6, the moving carriage 32 is operated to move the apparatus directly below the pipe 102. Next, as shown in FIG. 7, the carriage elevating drive motor 36 is operated to raise the elevating carriage 13, and the positioning head 11 attached to the tip of the rotary drive shaft 12 is inserted into the pipe 102.
[0040]
Next, air is supplied to the air cylinder 26 while adjusting the direction of the cover 23 so that the cover positioning lug 27 can be inserted into the adjacent pipe, and the cover 23 is slowly raised. Further, the cover 23 is raised until the packing 24 attached to the tip of the cover 23 comes into close contact with the inner surface of the end plate 101. In this state, the attachment state of FIG. 1 is obtained.
[0041]
Next, the rotary drive motor 15 is operated to rotate the rotary plate 16 around the rotary drive shaft 12, and the lift drive motor 22 is operated to connect the tip of the nozzle 28 to the welded portion of the end plate 101 and the pipe 102 and a predetermined portion. The rotary plate 16 is moved in the axial direction of the rotary drive shaft 12 to a position where the distance can be secured, and the nozzle 28 is moved to the water jet peening start position.
[0042]
Further, the high-pressure pump 52 is started and water is supplied through the nozzle 28 until the inside of the cover 23 is full (can be confirmed by overflowing water from the drain port 23a). Now, the water jet can be started.
[0043]
Next, the high-pressure pump 52 is activated and high-pressure water is sent to the nozzle 28 via the high-pressure hose 29, cavitation bubbles are generated from the nozzle 28, and the cavitation bubbles collide with the welded portion of the end plate 101 and the pipe 102. In this state, the rotation drive motor 15 is operated to rotate the rotation plate 16 around the rotation drive shaft 12, the nozzle 28 is rotated around the pipe 102, and the elevation drive motor 22 is operated to rotate the rotation plate 16. The nozzle 28 is moved in the axial direction of the pipe 102 by moving in the axial direction of the drive shaft 12.
[0044]
At this time, a program considering the welding shape based on the attachment angle between the end plate 101 and the pipe 102 is created in advance, and the rotation drive motor 15 and the elevation drive motor 22 are controlled by the program, so that the nozzle 28 is connected to the end plate 101 and the pipe. It is possible to move 360 degrees around the pipe 102 while keeping the distance from the welded portion 102 constant (see FIG. 8).
[0045]
At this time, the indispensable pool for generating cavitation bubbles can be stably formed by the rotating plate 16, the cover 23, the end plate 101, and the packing provided at each joint portion.
[0046]
Further, the bubbles generated by cavitation and the water that is supplied from the nozzle 28 and overflows can be collected from the drain port 23 a provided near the upper portion of the cover 23 without being scattered around the drain hose 25.
[0047]
FIG. 11 is a conceptual diagram showing that the cavitation jet has two impact pressure peaks along the jet axial direction, and (a) is a characteristic diagram showing the relationship between the standoff distance and the impact pressure generated from the jet. b) is a schematic diagram showing the state of a jet.
[0048]
As shown in this figure, the cavitation jet has two impact pressure peaks along the jet axis direction, and the second peak far from the nozzle 28 is compared to the first peak as shown in FIG. It is characterized by a wide range. Therefore, it is not always necessary to precisely adjust the distance between the construction target site and the nozzle 28.
[0049]
【The invention's effect】
As described above, according to the water jet peening apparatus of the present invention, it penetrates through the end plate of the pressure vessel held in the atmosphere, and penetrates the subordinate welded portion, particularly the end plate, which is welded and fixed to the inner surface of the pressure vessel. Thus, the spray nozzle can be opposed to the welded portion of the pipe that is welded and fixed, and the spray nozzle can be smoothly moved around the pipe. In addition, since a water pool can be stably formed around the welded part by installing a cover that matches the shape of the inner surface of the end plate and installing a drain outlet in the vicinity of the upper end of the cover, it is In the same way, cavitation bubbles can collide.
[0050]
As a result, the residual stress state on the surface of the welded portion can be reliably improved, and the reliability of the pressure vessel is improved.
[Brief description of the drawings]
FIG. 1 is a detailed view showing a state in which a water jet peening apparatus according to an embodiment of the present invention is installed in a pipe penetrating an end plate.
FIG. 2 is a cross-sectional view taken along the line AA of FIG.
3 is a cross-sectional view taken along the line BB in FIG.
4 is a cross-sectional view taken along the line CC of FIG. 3;
FIG. 5 is a system configuration diagram of a water jet peening apparatus according to the present invention.
FIG. 6 is a configuration diagram showing a state before the water jet peening apparatus of the present invention is installed in a pipe.
FIG. 7 is a configuration diagram showing a state in the middle of installing the water jet peening apparatus of the present invention in a pipe.
FIG. 8 is a configuration diagram showing a state in which water jet peening is applied to a head plate and a welded portion under the water jet peening apparatus of the present invention.
FIG. 9 is a cross-sectional view of a pressure vessel upper mirror in which a pipe penetrates and is fixed to a mirror plate by welding.
10 is an enlarged view of a main part of FIG. 9;
FIG. 11 is a conceptual diagram showing that a cavitation jet has two impact pressure peaks along the jet axis direction.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Positioning head 13 Lifting carriage 15 Rotation drive motor 16 Rotation plate 22 Lifting drive motor 23 Cover 28 Nozzle 32 Moving carriage 51 Control panel 52 High pressure pump 53 Water storage tank 101 End plate 102 Piping

Claims (4)

Piping having welds held in the atmosphere;
A nozzle that jets high-pressure water to generate cavitation bubbles in the water, collides the cavitation bubbles with the surface of the weld, and improves the stress state of the weld;
A pool forming means for forming a pool for holding the weld and the nozzle in water;
Rotating means having a rotational drive shaft for rotating the nozzle along the periphery of the welded portion
A positioning head comprising a positioning head attached to an upper end of the rotary drive shaft, and a positioning lug provided on an outer surface of the pool forming means ;
A water jet peening apparatus comprising: positioning the pool forming means by inserting the positioning head into the pipe and inserting the positioning lug into another pipe . 2. The water jet peening apparatus according to claim 1, further comprising a vertically moving means for moving the nozzle up and down along an axial direction of the pipe . 3. The water jet peening apparatus according to claim 1, further comprising moving means for moving a carriage on which the nozzle, the pool forming means, the positioning means, and the rotating means are mounted . The water jet peening apparatus according to any one of claims 1 to 3, wherein the pipe is welded to the inner surface of the pressure vessel, and a portion of the pool forming means facing the inner surface of the pressure vessel is adjusted to the curvature of the pressure vessel. A water jet peening apparatus characterized by having a shape .

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