JP2005161385A - Underwater welding equipment and underwater welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an underwater welding equipment capable of measuring the shape of a groove underwater, and applicable to a narrow part. <P>SOLUTION: The underwater welding equipment which is provided with a welding head having a welding wire feed system and an optical system to focus laser beams, and connected to a laser beam oscillator and a shield gas supply source to weld a part 23 to be welded of a structure underwater comprises a spindle 12 which is abutted on the part 23 to be welded and displaced according to the surface shape of the part 23, a position measurement instrument 14 to measure the displacement of the spindle 12, and a link to transmit the displacement of the spindle 12 to the position measurement instrument 14, and further comprises a gap sensing mechanism 18 to measure the gap between a tip of the welding head and the part 23 to be welded. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an underwater welding apparatus and an underwater welding method, and in particular, an underwater welding apparatus that performs groove overlay welding by irradiating a laser beam to a groove portion from which a crack has been removed when a crack occurs in an underwater structure or the like. And an underwater welding method.

  For example, when a crack occurs in a member such as an in-core structure of a nuclear reactor, the entire member is replaced or repaired by installing a reinforcing metal fitting on the crack-generating member.

  On the other hand, there is also a method of performing build-up welding (hereinafter referred to as groove build-up welding) on the groove portion after the crack is completely removed by a grinder, electric discharge machining, or the like. When performing this welding, it is necessary to perform welding with a constant gap between the tip of the welding head and the groove, so considering remote welding, the gap should be reduced. It is essential to measure. In addition, the reactor underwater structure of the nuclear reactor is often configured in a complicated manner, so it is necessary to cope with a narrow environment.

  As a first example of performing such processing, an underwater processing apparatus for performing underwater welding shown in Patent Document 1 is known, and FIG. 8 is a cross-sectional view showing the configuration thereof.

  As shown in FIG. 8, when welding a workpiece 40 in an underwater environment, the laser oscillator 1 is installed in the atmosphere, and the welding head body 3 is installed in the water. The inside of the welding head 3 and the vicinity of the welded portion 23 are locally excluded from the water 7 by the shielding gas 22 so as not to contact the water 7. In addition, a CCD camera (optical monitoring device) 41 is provided to monitor the processing state.

  When the material to be welded 40 has a flat surface, the welding head 3 having such a structure can be welded underwater. However, it is difficult to perform groove overlay welding without measuring the gap between the tip of the welding head and the groove.

  As a second example, an underwater welding apparatus shown in Patent Document 2 is known, and FIG. 9 is a cross-sectional view showing the configuration thereof.

  As shown in FIG. 9, the welding head 3 is attached to an underwater moving carriage that moves while adsorbing to an underwater wall surface, and a CCD camera 41 monitors the moving portion of the wall surface (material 40 to be welded) or the entire apparatus. Based on the data, the three-dimensional positioning mechanism 43 controls the three axes of the X axis, the Y axis, and the Z axis to position the welding head 3. Although the gap sensing method is unknown, since positioning is performed by a system using a CCD camera, there is a problem similar to the first example.

  As a third example, an underwater welding nozzle shown in Patent Document 3 is known, and FIG. 10 is a cross-sectional view showing the configuration thereof.

  As shown in FIG. 10, the vicinity of the welded portion 23 is covered with a shield wall (shield cover 19), filled with the shield gas 22, and the curtain water 44 is ejected in a skirt shape on the outer periphery of the shield wall. Perform underwater welding. Further, the welding state can be observed by the CCD camera 41 provided on the upper part of the welding head. In this example, no gap sensing method is proposed.

  In the above-described prior art relating to the underwater welding apparatus, gap sensing of the groove portion has not been proposed. On the other hand, as a gap sensing method for a groove portion, there are the following proposals in air welding.

  As a first example, an automatic welding copying control apparatus shown in Patent Document 4 is known, and FIG. 11 is a schematic configuration diagram of an automatic welding apparatus provided with the welding automatic copying control apparatus.

  FIG. 11 shows a typical example of a displacement meter using the slit projector 45. A slit-shaped light is irradiated near the welding line 46, the reflected light is captured by the camera 41, and the shape of the vicinity of the welding line 46 (here, fillet joint) is analyzed by analyzing the bending state of the light by the image processing device 47. Measure. It is considered that the shape of the groove portion after the crack removal can be measured in the same manner. However, since the light fluctuates in water, there is a problem that the groove shape cannot be measured accurately.

  As a second example, a welding apparatus shown in Patent Document 5 is known, and FIG. 12 is an explanatory diagram thereof.

  As shown in FIG. 12, this apparatus is for correcting the welding position in automatic welding, and after moving the welding torch 48 to the welding position, the sensor stylus 49 is projected by the air cylinder 50. The stylus 49 is moved in the X direction and brought into contact with the welding line 46 to detect the welding position in the X direction. After detecting the welding position, the stylus 49 of the sensor is retracted by the air cylinder 50. In this case, there is a problem in that it cannot be used underwater because there is a concern about leakage of the stylus 48 that handles electrical signals.

  As a third example, a welding groove shape measuring method shown in Patent Document 6 is known, and FIG. 13 is a schematic cross-sectional view of the welding groove shape measuring method.

As shown in FIG. 13, while moving the touch sensor 48 in the lateral direction (Y direction) of the groove section in the groove, the touch sensor 51 is lowered at every predetermined pitch to touch the groove side wall 11. The groove shape can be obtained by measuring the amount of vertical movement of the touch sensor 51. There is no problem in obtaining the groove shape in water, but considering the size of the touch sensor 51, there is a drawback that the height of the welding head is increased.
Japanese Patent No. 3006370 Japanese Patent Laid-Open No. 11-216586 Japanese Patent Laid-Open No. 2003-88959 JP 2003-48070 A Japanese Patent Laid-Open No. 10-29063 JP-A-10-193107

  In the above-described underwater welding apparatus, groove shape measurement is a problem. Also, in groove shape measurement, it is difficult to apply a laser displacement meter or a sensor stylus underwater. And if a touch sensor is used as it is, the height of a welding head will become large, for example, the point which cannot be used in a narrow part like the in-core underwater structure of a nuclear reactor is a subject.

  The present invention has been made in consideration of the above-described points, and an object thereof is to provide an underwater welding apparatus capable of measuring a groove shape in water and corresponding to a narrow portion and a method thereof.

In order to achieve the above object, the present invention
In an underwater welding apparatus having a welding wire supply source and supply system and a welding head having an optical system for condensing laser light, and connected to a laser oscillator and a shield gas supply source to repair a welded portion of a structure in water A spindle that comes into contact with the welded portion and is displaced according to the shape of the welded portion, a position measuring device that measures a given amount of mechanical displacement, and a link that transmits the displacement of the spindle to the position measuring device. And an underwater welding apparatus, comprising a gap sensing mechanism for measuring a gap between a tip of the welding head and the welded part, a welding wire supply source and supply system, and a laser beam. It has a welding head with an optical system that emits light and is connected to a laser oscillator and a shield gas supply source to compensate the welded part of the structure in water. An underwater welding method for repairing, wherein a gap sensing mechanism is used to measure a gap between the tip of the welding head and the welded part,
Is to provide.

  In the present invention, since gap measurement is performed using the gap sensing mechanism as described above and underwater welding is performed based on the gap measurement, the narrow gap is narrowed based on the accurately measured gap between the welding head and the welded portion. It is possible to weld well even at the part.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  In each of the following examples, the present invention is applied to underwater welding work in a reactor pressure vessel. In addition, the same reference numerals are given to common components in each of the following embodiments, and redundant description will be omitted.

  FIG. 1 is an explanatory view showing a first embodiment of the present invention. As shown in FIG. 1, a laser oscillator 1 and a shield gas supply source 2 are installed outside the reactor. The welding head 3 is coupled to each end of an optical fiber 4 for light transmission, a tube 5 for shielding gas supply, and a control cable 6 for signal transmission connected to the laser oscillator 1 and the shield gas supply source 2. In this state, it is immersed in the reactor water 7 of the reactor pressure vessel and suspended to a predetermined position facing the reactor internal structure 27.

  The welding head 3 includes a welding wire case 9 for inserting a reel around which the welding wire 21 is wound, a welding wire supply mechanism 10 including a motor 26 for supplying and driving the welding wire 21, and a welding head tip portion 29.

  FIG. 2 is an explanatory diagram showing the welding head tip portion 29. As shown in FIG. 2, the welding head front end portion 29 is made of a material having flexibility and appropriate water pressure rigidity, and surrounds a portion to be welded (not shown) to shield it from water. 19, the nose part 24 in which the gap sensing mechanism 18 and the optical system 8 are accommodated is provided.

  The gap sensing mechanism 18 is provided via the spindle 12 that contacts the welded portion and is displaced according to the surface shape of the welded portion, the link 13 that transmits the displacement of the spindle 12 to other members, and the link 13. The position measuring device 14 outputs a value corresponding to the amount of displacement of the spindle 12, the bearing 16 that supports the spindle 12, and the fulcrum 17 that supports the link 13.

  As the position measuring instrument 14, a potentiometer, a differential transformer, a micrometer, or a linear encoder can be used. These can be selected in terms of water resistance and compactness.

  As the shape of the spindle 12, an appropriate one is used, such as a cylinder, a cylinder with a hemisphere or a sphere at the tip, or a cone with a hemisphere or a sphere at the tip. The smaller the radius of the tip hemisphere or sphere, the smaller the unevenness can be measured. However, if the radius is too small, there is a risk of being caught by the unevenness of the measurement target and possibly being stuck. From the welding gap tolerance, the radius is preferably about 0.2 to 5 mm, for example.

  In the first embodiment configured as described above, in order to perform overlay welding on the groove portion 11 from which the crack having the opening portion on the surface is removed, first, the laser oscillator 1 installed outside the nuclear reactor. Underwater welding is started in a state where the welding head 3 connected to the shield gas supply source 2 is suspended from a predetermined position of the in-furnace structure 27.

  FIG. 3 is a cross-sectional view showing the tip of the welding head 3 during welding. First, when the laser light output from the laser oscillator 1 is transmitted to the welding head 3 through the optical fiber 4, the laser light 20 is collected by the optical system 8 and irradiated onto the welding portion 23.

  Further, the welding wire 21 built in the welding wire case 9 is supplied to the welding portion 23 by the welding wire supply mechanism 10. Further, the shield gas 22 from the shield gas supply source 2 is supplied to the welded portion 23 from the same hole as the laser beam 20 through the tube 5. In this way, welding is performed while spraying the shielding gas and supplying the welding wire 21 while irradiating the welded portion 23 with the laser beam 20.

Table 1 below shows an example of welding conditions. Laser output is 0.8-4.0kW, welding speed is 0.1-2m / min, wire diameter of welding wire is 0.6-1.2mm, wire speed is 0.1-2m / min, shield gas flow rate is 20-80 l / min Under certain conditions, welding is possible in water.

  A spindle 12 that moves following the shape of the groove portion 11 while moving the entire welding head 3 in the welding direction with the spindle 12 provided in front of the welding direction in contact with the groove portion 11 during the welding operation. The so-called gap 28 is converted into a left and right movement by the link 13, and the gap 28 is obtained as a measurement value by the position measuring device 14.

  Based on the data of the gap 28, welding is performed while performing so-called delayed copying in consideration of the distance between the spindle 12 and the welded portion 23 so that the gap 28 between the welding head tip portion 29 and the groove portion 11 is constant. To implement. It should be noted that the operation control of each component including the delay copying based on the data of the gap 28 is managed by a central control device (not shown).

  FIG. 4 is a schematic view of the tip of the welding head 3 during the second layer welding. As shown in FIG. 4, the welding is performed while blowing the shield gas and supplying the welding wire 21 while irradiating the laser beam 20 to the welded portion 23 in substantially the same manner as the first layer.

  At this time, the shape of the groove portion 11 is measured by the spindle 12 provided in front of the welding direction, and the gap 28 between the welding head tip portion 29 and the first weld layer upper portion 29 is based on the measurement data. The delay copying is performed so that becomes constant. When the height of the stacked welded portions 23 becomes substantially the same as the height of the surrounding base material, the groove overlay welding is completed.

  According to this first embodiment, welding can be performed while measuring the gap shape and measuring the gap between the welding head tip 29 and the groove portion or the upper portion of the already welded portion by delayed copying. Groove welding is possible in water.

  In the second embodiment, in addition to the structure of the first embodiment, there is a drive device for pulling up the spindle, and the gap measurement is divided as the first step, and the groove overlay welding is separated from the welding as the second step. To implement.

  FIG. 5 is a cross-sectional view of the welding head tip 29 during the gap measurement of the first step in the second embodiment.

  First, the entire welding head 3 is moved in the welding direction while bringing the spindle 12 into contact with the groove portion 11 without driving the laser oscillator 1. The amount of movement in the vertical direction of the spindle 12 that moves in accordance with the shape of the groove portion 11, that is, a so-called gap 28 is converted into a left and right movement by the link 13, and the gap 28 is obtained as a measurement value by the position measuring instrument 14. Based on the gap data, the distribution of the gap 28 in the groove 11 is obtained before welding.

  FIG. 6 is a cross-sectional view of the tip of the welding head during welding, which is the second step. When the measurement of the gap 28 is completed, the spindle 12 is pulled up by the driving device 15.

  As the driving device 15, an air cylinder, a combination of a rack and pinion and a motor, a combination of a linear guide and a motor, or the like can be used. Among these, an air cylinder is particularly advantageous for downsizing the driving device 15. In the figure, the position measuring device 14 and the driving device 15 are coaxially arranged in series, but they may be arranged in parallel, for example, by using different shaft structures.

  Next, welding is performed while spraying a shield gas and supplying the welding wire 21 while irradiating the welded portion 23 with the laser beam 20. At this time, welding is performed while controlling the gap 28 between the welding head tip portion 29 and the groove portion 11 to be constant based on the gap distribution obtained in advance by the movement of the spindle 12.

  As with the above procedure, the second and subsequent layers of welding are repeatedly subjected to gap measurement and welding until the height of the stacked welded parts 23 is substantially the same as the height of the surrounding base material. Repeat welding.

  According to the second embodiment, the groove shape is measured in advance, the gap distribution is obtained, and the gap between the welding head tip 29 and the upper surface of the weld groove 11 or the already welded portion 23 is further determined. Welding is possible while measuring. Therefore, groove overlay welding is possible in water.

  As in the second embodiment, the third embodiment is provided with a drive device 15 for pulling up the spindle, and performs gap measurement and welding simultaneously.

  FIG. 7 is a cross-sectional view showing the welding head tip 29 during welding. At the same time as the laser beam 20 is irradiated to the welded portion 23, welding is performed while spraying a shielding gas and supplying the welding wire 21.

  In addition, while moving the entire welding head 3 in the welding direction while the spindle 12 provided in front of the welding direction is in contact with the groove portion 11, the spindle 12 moves in the vertical direction according to the shape of the groove portion 11. The amount of movement, so-called gap 28, is converted into left and right movement by the link 13, and the gap 28 is obtained as a measurement value by the position measuring device 14.

  Based on the gap data, welding is performed while performing delayed copying so that the gap 28 between the tip of the welding head 3 and the groove 11 is constant. The groove build-up welding operation is repeated until the height of the stacked welded portions 23 becomes substantially the same as the height of the surrounding base material.

  According to the third embodiment, while measuring the shape of the groove 11, the gap between the tip of the welding head 3 and the upper portion of the weld groove 11 or the welded portion 23 that has already been laminated is controlled by delayed tracing. Since welding is possible, groove overlay welding is possible in water.

The perspective view which shows the 1st Example of the underwater welding apparatus which concerns on this invention. The perspective view which shows the welding head front-end | tip of the apparatus in FIG. Sectional drawing which shows the welding head front-end | tip during welding in the apparatus of FIG. 1, FIG. Sectional drawing which shows the welding head front-end | tip in the 2nd layer welding in the apparatus of FIG. 1, FIG. Sectional drawing which shows the welding head front-end | tip in the gap measurement in the 2nd Example of the underwater welding apparatus which concerns on this invention. Sectional drawing which shows the welding head front end in welding in 2nd Example. Sectional drawing which shows the welding head front end in welding in the 3rd Example of the underwater welding apparatus which concerns on this invention. Sectional drawing which shows the structural example of the conventional underwater processing apparatus. Sectional drawing which shows the structural example of the conventional underwater welding apparatus. Sectional drawing which shows the structural example of the conventional underwater welding nozzle. The schematic block diagram which shows the automatic welding apparatus provided with the conventional welding automatic copying control apparatus. Explanatory drawing which shows the conventional welding apparatus. The schematic sectional drawing which shows the conventional welding groove shape measuring method.

Explanation of symbols

1 laser oscillator, 2 shield gas supply source, 3 welding head, 4 optical fiber,
11 groove portion, 18 gap sensing mechanism, 20 laser beam

Claims (5)

In an underwater welding apparatus comprising a welding head having a welding wire supply system and an optical system for condensing laser light, and connected to a laser oscillator and a shield gas supply source to weld a welded portion of a structure in water.
A spindle that comes into contact with the welded portion and is displaced according to the surface shape of the welded portion, a position measuring device that measures the displacement amount of the spindle, and a link that transmits the displacement amount of the spindle to the position measuring device And a gap sensing mechanism for measuring a gap between the welding head and the welded portion. The underwater welding apparatus according to claim 1,
The underwater welding apparatus, wherein the gap sensing mechanism further includes a driving device for pulling up the spindle. The underwater welding apparatus according to claim 1 or 2,
An underwater welding apparatus comprising the gap sensing mechanism and a shield cover configured by a flexible member and enclosing the welded portion. In an underwater welding method comprising a welding head having a welding wire supply system and an optical system for condensing laser light, and connected to a laser oscillator and a shield gas supply source to weld a welded portion of a structure in water,
An underwater welding method, wherein a gap between the welding head and the welded part is measured. The underwater welding method according to claim 4,
An underwater welding method characterized in that a shield gas is filled around the welded portion.

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