JPH09136261A - Water jet peening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce residual stresses in the welded parts of a piping welded- fixed to the inner surface of a pressure container by allowing the inner surface of the pressure container to engage with a rotary plate to form pools for holding the welded parts and a nozzle in water. SOLUTION: A high pressure pump is started to feed highly pressurized water to a nozzle 28 through a high pressure hose 29 to generate cavitation air bubbles from the nozzle 28, and to allow the cavitation air bubbles to strike the welded parts of a panel board 101 to a piping 102. In this state, a rotary driving motor 15 is operated to rotate a rotary plate 16 around a rotary driving shaft 12, and to rotate the nozzle 28 around the piping 102. At this time, pools which are essential in generating the cavitation air bubbles, are stably formed due to packings provided at the rotary plate 16, a cover 23, the panel board 101 and their junctions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water jet peening apparatus for improving a tensile residual stress existing in a metal material to prevent stress corrosion cracking by injecting a liquid jet to a metal member, and more particularly, The present invention relates to a water jet peening apparatus which penetrates an end plate of a pressure vessel and improves a stress state of a welded portion surface of a pipe welded and fixed to an inner surface of the pressure vessel while being kept in the atmosphere.

[0002]

2. Description of the Related Art As a method for relaxing residual stress in a welded portion or the like which causes stress corrosion cracking, Japanese Patent Laid-Open No. 62-6361.
There is a technique disclosed in Japanese Patent No. 4 publication.

This is because a high-pressure water shot peening apparatus having a rotary nozzle section for injecting a high-pressure liquid jet is inserted into the inside of a tube such as a heat exchanger, which is an object of residual stress improvement, and the axial dynamic pressure energy of the jet itself is inserted. By peening the inner surface of the tube with (dynamic energy of the jet jet in the axial direction), the tensile residual stress originally present in the tube is softened to the compressive residual stress.

Further, in the technique disclosed in Japanese Patent Laid-Open No. 6-62408, the pressure vessel is filled with water at a high pressure in water against the welded portion of a pipe which is fixed by welding through the lower mirror portion of the pressure vessel. By jetting a jet, cavitation bubbles are generated to improve the surface stress state.

In this proposal, the apparatus is set at a predetermined position by utilizing the internal structure of the pressure vessel and the through pipe while the pressure vessel is filled with water, and the nozzle is rotated around the pipe to target the object. This makes it possible to improve the stress of the welded part.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The prior art disclosed in Japanese Patent No. 614 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 the welding shape is also simple, it is thought that the water used and the device used can be relatively easily implemented.

Further, in the prior art disclosed in Japanese Patent Laid-Open No. 5-78738, since the apparatus can be installed in water and by utilizing the structure inside the pressure vessel, it is not necessary to collect water and at the same time cavitation bubbles are generated. There is no need to pay attention to creating a water environment to generate.

FIG. 9 is a sectional view of the end plate portion of the pressure vessel, FIG.
FIG.

End plate 101 of pressure vessel held in the atmosphere
A number of pipes 1 that penetrate through the pipe and are welded and fixed to the inner surface of the pressure vessel
No. 02 is provided, the welding is performed from the inner surface to the end plate 101 as shown in FIG. 10, and the residual stress of the welded portion is high tensile residual stress including the weld metal 103 and its vicinity. The part 104 is generated.

To improve the residual stress in the welded portion, the welded portion should be the outer surface of the pipe and the end plate of the pressure vessel, and the welded part should have a three-dimensional shape in the pipe fixed to the end plate. As a result, it is necessary to perform complicated position control of the injection nozzle, and also to perform water peening when peening is performed in the atmosphere, especially in the case of a reactor pressure vessel, to prevent the spread of contamination.

Further, in order to generate cavitation bubbles in water to improve the residual stress, it is necessary to form a water environment in the relevant portion and at the same time, recover water in the same manner as described above. It is an object of the present invention to provide a water jet peening apparatus capable of improving residual stress in a welded portion of a pipe welded and fixed to the inner surface of a pressure vessel.

[0012]

Means for Solving the Problems The above-mentioned object is to provide a welded portion of a pipe which penetrates the end plate of a pressure vessel held in the atmosphere and is welded and fixed to the inner surface of the pressure vessel at a position facing the welded portion. In a water jet peening device that generates cavitation bubbles by injecting high-pressure water from the installed nozzle and collides the cavitation bubbles with the surface of the weld to improve the stress state of the weld, the device is inserted inside the pipe, A positioning device for aligning the
Further, it is possible to form a rotary plate to which a nozzle is attached, a drive device for rotating the rotary plate, and a welded portion and a pool for holding the nozzle in water by engaging with the inner surface of the pressure vessel and the rotary plate. And a cover configured as described above.

Further, in the first means, the rotary plate is provided so as to be slidable in the axial direction of the pipe, and the drive device is provided so that the position of the rotary plate can be controlled. This is achieved by the second means which makes it possible to keep the relative distance between the nozzle and the welded portion constant with respect to the welded portion of the existing pipe.

Further, in the first or second means, it is achieved by the third means in which the devices constituting the apparatus are arranged on the carriage.

In any one of the first to third means, the portion of the cover that engages with the inner surface of the pressure vessel is shaped to match the curvature of the pressure vessel, and the drain port is provided near the highest position of the cover. 4 means.

Further, when the water jet peening apparatus of any of the first to fourth means is used in a place where a plurality of pipes are regularly arranged, a projection which can be inserted into an adjacent pipe to correct the direction of the cover is provided. This is achieved by the fifth means attached to the outer surface of the cover.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The outline of the present invention will be described first.

The trolley on which the device is placed is moved to the bottom of the pipe, the positioning device is inserted into the pipe, the center of the device is aligned, and the cover is pressed so that its edge closely contacts the inner surface of the pressure vessel. At this time, a packing having a shape matching the curvature of the pressure vessel is provided on the upper end of the cover, and a packing is provided between the rotary plate and the cover, thereby forming a closed space between the cover, the rotary plate and the inner surface of the pressure vessel. be able to.

In this state, the cover is filled with water to form a pool, the high pressure jet liquid is jetted from the jet nozzle to generate cavitation bubbles, and the rotary drive device of the rotary plate is operated to rotate the rotary plate. In addition, by operating the axial drive device of the rotary plate to move the rotary plate in the axial direction, the injection nozzle fixed to the rotary plate is rotated around the pipe and moved in the axial direction of the pipe. You can

Further, by controlling the position of each drive motor by the control device, the injection nozzle can be made to uniformly face the welded portion of the pressure vessel and the pipe, and stable cavitation bubbles can be formed in the welded portion. It can be made to collide and the residual stress on the weld surface can be improved.

At this time, the water and air bubbles jetted from the jet nozzle are guided to the outside from the discharge port provided near the upper end of the cover and easily collected.

Further, by inserting the projections attached to the outer surface of the cover into the adjacent pipes, the direction of the cover is always kept constant even if the rotary plate rotates and moves, so that the sealing surface with the pressure vessel is sealed. It is possible to form a pool stably without any deviation. Hereinafter, a specific description will be given with reference to the drawings.

FIG. 1 is a cross-sectional view showing a state in which the water jet peening apparatus of the present invention is installed in a pipe 102 penetrating an end plate 101 of a pressure vessel and fixed by welding.

2 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is a sectional view taken along the line BB of FIG. 1, and FIG. 4 is a sectional view taken along the line CC of FIG.

In FIG. 1, a positioning head 11 is rotatably fixed to an upper end of a rotary drive shaft 12 through a bearing 12a, and a lower end portion thereof is rotatably passed through a lift truck 13 through a bearing 12b. It is fixed and its tip is connected to a rotary drive motor 15 via a coupling 14.

Further, the center portion of the rotary drive shaft 12 has a spline structure (see FIG. 2), is installed so as to penetrate through the rotary cylinder 17, and is fixed in the rotary cylinder 17 inside the spline nut 17a and the axial direction. Movably engaged with. The rotary plate 16 is fixed to the upper end of the rotary cylinder 17, and the rotary drive motor 15 rotates to rotate the rotary plate 16 via the rotary drive shaft 12, the spline nut 17 a, and the rotary cylinder 17. .

On the other hand, an elevating flange 18 is rotatably fixed to the lower end of the rotary cylinder 17 through a bearing 18a, and the elevating screw shaft shaft 1 is attached to the elevating flange 18.
A nut 19a that meshes with 9 is fixed. A lower end of the lifting screw shaft shaft 19 is rotatably fixed through the lifting carriage 13 via a bearing 19b, and a lifting shaft rotation gear 20 is attached to a tip end thereof.

The transmission gear (A) 21a is rotatably fixed via a rotary drive shaft 12 penetrating the center thereof and a bearing 21d, and is also transmitted via an elevating shaft rotary gear 20 and a transmission gear (B) 21b. (C) Engages with the lifting drive motor 22 to which 21c is attached (see FIGS. 3 and 4).

With this configuration, the transmission gears (C) 21c, (B) 21b, (A) 2 are rotated by the rotation of the elevation drive motor 22.
1a and the elevating shaft rotating gear 20 can be used to rotate the elevating drive shaft 19 to elevate the elevating flange 18 fixed with the nut 19a engaged therewith, and further elevate the rotating cylinder 17 and the rotating plate 16. You can

Since the bearings are arranged between the rotary drive system and the elevating drive system, the respective operations can be performed without mutual influence.

The cover 23 has the rotary plate 16 arranged therein, and a packing 24 adapted to the inner surface shape of the end plate 101 is attached to the upper end thereof. A drain port 23a is provided near the upper end of the cover 23 so that a drain hose 25 can be connected.

Air cylinder 2 fixed to the lift truck 13.
The tip of 6 is a flange 2 provided on the outer periphery of the cover 23.
3b and the cover 23 are fixed so as to be movable in the circumferential direction. Further, a cover positioning lug 27 is provided on the outer surface of the cover 23 so that the cover 23 can be inserted into an adjacent pipe and the orientation of the cover 23 can be fixed.

The nozzle 28 penetrates the rotary plate 16, the tip of which is fixed toward the welded portion of the pipe 102 and the end plate 101, and the other end is connected to a high-pressure hose 29.

All of the above-mentioned devices are fixed to the lifting carriage 13, and the lifting carriage 13 moves via a linear guide 30 on a rail 31 fixed to a moving carriage 32. Also,
A nut 33 is attached to the lifting truck 13 and meshes with a truck lifting screw shaft 34 fixed to the moving carriage 32.

The dolly lifting screw shaft 34 is connected to a dolly lifting drive motor 36 via a timing belt 35.
By rotating 4, the lift truck 13 can be moved up and down. A caster 37 is attached to the moving carriage 32.

On the other hand, packings 16a and 16b are attached between the rotary plate 16 and the cover 23 and the rotary drive shaft 12 so as to seal the water stored in the cover 23 and form a water pool. There is.

The drive motors, air hoses and the like 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).

Next, the operating procedure of the water jet peening apparatus constructed as above will be described.

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 trolley lifting / lowering drive motor 36 is operated to raise the lifting / lowering trolley 13, and the positioning head 11 attached to the tip of the rotary drive shaft 12 is inserted into the pipe 102.

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 mounting state shown in FIG. 1 is obtained.

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 move the tip of the nozzle 28 to the end plate 1.
01 and the welded portion of the pipe 102, the rotary plate 16 is moved in the axial direction of the rotary drive shaft 12 to a position where a predetermined distance can be secured, and the nozzle 2 is placed at the water jet peening start position.
Move 8

Further, the high pressure pump 52 is started to fill the inside of the cover 23 through the nozzle 28 (the drain port 2
It can be confirmed by the overflow of water from 3a) Supply water. Now the water jet can be started.

Next, the high pressure pump 52 is started to send high pressure water to the nozzle 28 through the high pressure hose 29, and the nozzle 28
Cavitation bubbles are generated from the cavitation bubbles, and the cavitation bubbles collide with the welded portions of the end plate 101 and the pipe 102. In this state, the rotary drive motor 15 is operated to rotate the rotary plate 16 around the rotary drive shaft 12, and the nozzle 28
Is rotated around the pipe 102, the lift drive motor 22 is operated to move the rotary plate 16 in the axial direction of the rotary drive shaft 12, and the nozzle 28 is moved in the axial direction of the pipe 102.

At this time, a program considering the welding shape based on the mounting angle of the end plate 101 and the pipe 102 is prepared in advance, and the rotary drive motor 15 and the elevation drive motor 22 are controlled by the program, whereby the nozzle 28
Can move 360 degrees around the pipe 102 while keeping the distance between the end plate 101 and the welded portion of the pipe 102 constant (see FIG. 8).

At this time, the rotating plate 16, the cover 23, the end plate 101, and the packings provided at the respective joints can stably form an indispensable pool for generating cavitation bubbles.

Further, the bubbles generated by the cavitation and the water which is supplied from the nozzle 28 and overflows from the drain hose 2 provided in the vicinity of the upper portion of the cover 23.
It can be collected via 5 without being scattered around.

FIG. 11 is a conceptual diagram showing that the cavitation jet has two impact pressure peaks along the jet axis direction, and FIG. 11A is a characteristic showing the relationship between the standoff distance and the impact pressure generated from the jet. FIG. 1B is a schematic diagram showing a jet flow state.

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 the first peak as shown in the figure. It has a wider range compared to. Therefore, the distance between the construction target site and the nozzle 28 does not necessarily need to be precisely adjusted.

[0049]

As described above, according to the water jet peening apparatus of the present invention, the subordinate welding portion which penetrates the end plate of the pressure vessel held in the atmosphere and is welded and fixed to the inner surface of the pressure vessel, in particular, The jet nozzle can face the welded portion of the pipe that is obliquely penetrated through the end plate and fixed by welding, and the jet nozzle can be smoothly moved around the pipe. In addition, by installing a cover that matches the shape of the inner surface of the end plate and installing a drainage port near the upper end of the cover, a stable water pool can be formed around the welded part, so that the welded part is Similarly, cavitation bubbles can be collided.

As a result, the residual stress state on the surface of the welded portion can be surely 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 sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along the line CC of FIG. 3;

FIG. 5 is a system configuration diagram of the water jet peening apparatus of the present invention.

FIG. 6 is a configuration diagram showing a state before installing the water jet peening apparatus of the present invention 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 the water jet peening apparatus of the present invention is used and water jet peening is applied to the end plate and the underlying welded portion.

FIG. 9 is a cross-sectional view of the pressure vessel upper mirror in which the pipe penetrates the end plate and is fixed by welding.

FIG. 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]

 11 Positioning Head 13 Elevating Cart 15 Rotation Drive Motor 16 Rotating Plate 22 Elevating Drive Motor 23 Cover 28 Nozzle 32 Moving Cart 51 Control Panel 52 High Pressure Pump 53 Water Tank 101 End Plate 102 Piping

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazunori Sato 3-36 Takaracho, Kure City, Hiroshima Prefecture Bab Kotsk Hitachi Ltd., Kure Research Laboratory (72) Koichi Kurosawa 3-1-1, Saiwaicho, Hitachi City, Ibaraki Prefecture Stock company Hitachi Ltd. Hitachi factory (72) Inventor Kenji Okada 6-9 Takara-cho, Kure-shi, Hiroshima Babkotsu Hitachi Hitachi Kure factory

Claims (5)

[Claims] 1. High-pressure water is jetted from a nozzle installed at a position facing a welded portion of a pipe, which penetrates an end plate of a pressure vessel held in the atmosphere and is welded and fixed to the inner surface of the pressure vessel, to the welded portion. In the water jet peening apparatus that generates cavitation bubbles by doing so and collides the cavitation bubbles with the surface of the welded portion to improve the stress state of the welded portion, the water jet peening apparatus is inserted inside the pipe to align the apparatus. A positioning device, a rotary plate rotatably attached to the positioning device and having the nozzle attached, a drive device for rotating the rotary plate, an inner surface of the pressure vessel and the rotary plate. And a cover configured to form a pool for holding the welded portion and the nozzle in water. O over Tar jet peening apparatus. 2. The method according to claim 1, wherein the rotary plate is provided so as to be slidable in the axial direction of the pipe,
The drive device is provided so as to control the position of the rotary plate, and the relative distance between the nozzle and the welded portion is constant with respect to the welded portion of the pipe that is inclined and welded to the pressure vessel. A water jet peening device characterized in that it can be held. 3. The water jet peening apparatus according to claim 1 or 2, wherein the devices constituting the apparatus are arranged on a carriage. 4. A drainage port according to claim 1, wherein a portion of the cover that engages with the inner surface of the pressure vessel is shaped to match the curvature of the pressure vessel, and a drain port is provided near the highest position of the cover. A water jet peening machine characterized by that. 5. When the water jet peening apparatus according to any one of claims 1 to 4 is used in a place where a plurality of the pipes are regularly arranged, the water jet peening device can be inserted into an adjacent pipe to correct the direction of the cover. A water jet peening machine characterized by having protrusions attached to the outer surface of the cover.