Laser welding process for upper guide cylinder of nuclear power reactor internals

Abstract

The invention relates to a laser welding process for an upper guide cylinder of a nuclear power reactor internal and an auxiliary tool thereof. The tool comprises an adjusting support, an upper base, a lower base and end covers, the top of the adjusting support is movably connected with the lower end face of the lower base, the upper base and the lower base are symmetrically arranged along the axis, and the two ends are fixedly connected through the end covers. And a plurality of adjusting blocks are arranged on the upper base and the lower base and are used for adjusting the welding seam levelness of the nuclear power reactor internals. The welding process comprises the steps that the height of the adjusting support is adjusted to enable the lower base to be horizontal, nuclear power reactor internals are placed, the upper base is buckled, the end cover is connected and pre-tightened, the position of the upper base is adjusted to enable the upper base to be horizontal with the lower base, the adjusting block is adjusted to enable a weld joint to be horizontal, and finally laser welding is conducted. In the welding process, spot welding and fixing are conducted through laser welding, and then laser penetration welding is conducted; through the design of the adjusting bracket and the adjusting block, the levelness and the welding quality of a welding seam are ensured, the welding efficiency is improved, the cost is reduced, the operation process is simplified, and the high-precision welding device is particularly suitable for the high-precision welding requirement of nuclear power reactor internals.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical processing, and in particular to a laser welding process for an upper guide tube of a nuclear power reactor internal component. Background Art

[0002] Nuclear power plants are an important part of the modern energy supply system, with nuclear reactors at their core. In nuclear reactors, the control rod guide cylinder assembly is one of the key components used to accurately control the nuclear fission reaction rate. As part of the control rod guide cylinder assembly, the upper guide cylinder assembly is responsible for ensuring that the control rods can move smoothly inside the nuclear reactor, thereby achieving effective regulation of the nuclear reaction rate. Therefore, the structural stability and service life of the upper guide cylinder assembly directly affect the safe operation of the nuclear reactor and the overall performance of the nuclear power plant.

[0003] In the manufacturing process of nuclear power reactor internals, welding of the upper guide cylinder assembly is a crucial process. At present, the industry generally uses electron beam welding (EBW) technology to weld such precision parts. Electron beam welding technology has the advantages of deep penetration, small heat-affected zone, and fast welding speed, and is suitable for welding tasks with high precision and high strength requirements. However, this technology also has some obvious limitations: 1. Traditional fixtures and fixtures cannot guarantee accurate position control of the internal components during welding, especially when the weld position needs to be adjusted multiple times. Repeated positioning operations will increase the workload and may introduce additional errors. 2. The thermal stress generated during welding often causes deformation of the internal components of the pile, and existing tools lack effective means to suppress this deformation, thus affecting the welding quality and consistency of parts; 3. Due to the lack of fixing and adjustment tools designed specifically for in-pile components, each change in weld position requires recalibration, which greatly reduces welding efficiency. Summary of the invention

[0004] In view of the technical problems existing in the background technology, the present invention provides a laser welding process for the upper guide tube of the nuclear power reactor internal component, which can maintain or even exceed the welding quality of the existing technology and effectively solve the above limitations, becoming an urgent problem to be solved in the field of nuclear power reactor internal component manufacturing. In particular, the research and development of new welding technology is particularly important in terms of improving welding efficiency, reducing costs, simplifying operation procedures, etc.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: A laser welding process for the upper guide tube of a nuclear power reactor internal component, the process uses a tool for assisting the welding of a semi-square tube, the tool comprises an adjustment bracket, an upper base, a lower base and an end cover, the top of the adjustment bracket is movably connected to the lower end surface of the lower base, the upper base and the lower base are symmetrically arranged along an axis, the upper base and the lower base are connected with the end cover at the front and rear ends, the nuclear power reactor internal component is placed between the upper base and the lower base during welding, and a plurality of adjustment blocks are arranged in parallel on the upper base and the lower base; The welding process includes the following steps: S1. Adjust the height of the bracket so that the lower base is on the same horizontal plane; S2. Place the nuclear power reactor internals in the lower base, and buckle the upper base onto the lower base; S3, connect the end covers on both sides to the upper base and the lower base, and pre-tighten the end covers; S4. Adjust the position of the upper base to keep the upper base and the lower base level. After the adjustment, tighten the end cover for the second time. S5. Adjust the adjustment blocks on the upper base and the lower base so that the welds of the nuclear power reactor internal components are on the same horizontal plane; S6. Weld the welds of the internal components of the nuclear power reactor.

[0006] In a preferred solution, the adjustment bracket includes a support column, a top plate and a support bolt; the top of the support column is vertically connected to the top plate, the support bolt is threadedly connected to the top plate, and the lower base is placed on the support bolt.

[0007] In a preferred solution, first threaded holes are correspondingly opened on the lower end surfaces of the top plate and the lower base, and locking bolts are threadedly connected to the first threaded holes to lock and fix the positions of the lower base and the top plate.

[0008] In the preferred scheme, the adjustment block includes a pressure block, a clamping plate, a tightening bolt and a second connecting bolt; adjustment holes are equidistantly opened on the upper base and the lower base, a pressure block is placed in the adjustment hole, a clamping plate is arranged above the pressure block, both sides of the top plate are threadedly connected to the upper base and the lower base through the second connecting bolt, a second threaded hole is opened at the center position of the clamping plate, the tightening bolt is threadedly connected to the second threaded hole and abuts against the pressure block.

[0009] In a preferred solution, the end cover includes a side plate, and strip holes are formed at the ends of the upper base and the lower base. The first connecting bolt passes through the strip hole and is threadedly connected to the side of the side plate.

[0010] In a preferred solution, the side portion of the side plate is fixedly connected to a mounting plate, and a laser collimator is vertically mounted on the mounting plate.

[0011] In a preferred solution, a level is installed on the upper end surface of the upper base.

[0012] In the preferred scheme, in S6, the welding of the internal components of the nuclear power reactor is carried out by first performing laser spot welding to fix them, and then performing laser deep penetration welding. The laser power of the spot welding section is controlled at about 2100w, and the laser power of the deep penetration welding section is controlled at about 2100w. Nitrogen is used as the shielding gas for welding, and its shielding gas flow rate is controlled at about 10-20L / min.

[0013] A laser welding process for the upper guide tube of a nuclear power reactor internal component. The beneficial effects of this method include but are not limited to the following points: 1. This process can achieve fine adjustment of the height of the lower base by adjusting the support bolts on the bracket and using them in conjunction with the top plate, ensuring that the semi-square tube maintains an ideal level during the welding process. In addition, the adjustment block between the upper base and the lower base can accurately fix the position of the semi-square tube to avoid welding quality problems caused by position offset; 2. The combination of the pressing block and the clamping plate designed in the present invention can apply uniform pressure to the surface of the semi-square tube, which helps to suppress thermal deformation during welding, thereby ensuring the dimensional stability and flatness of the weld after welding; 3. By setting strip holes at the ends of the upper base and the lower base, it is convenient to fine-tune the position of the base, further ensuring the flatness of the base; 4. The laser collimator on the end cover can conveniently and accurately measure the horizontality of the weld, avoiding welding defects caused by inaccurate positioning; 5. The present invention adopts a welding method that combines laser spot welding and laser deep penetration welding. Compared with traditional electron beam welding, its efficiency is improved by about 2 times, which saves labor costs and shortens product manufacturing cycle. In addition, the weld formation is stable and the welding quality is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the adjusting bracket of the present invention; Figure 3 A bottom view of the adjustable support structure of the present invention; Figure 4 It is an enlarged schematic diagram of the regulating block structure of the present invention; Figure 5 It is an enlarged schematic diagram of the end cover structure of the present invention; Figure 6 It is an enlarged schematic diagram of the structure of the level instrument of the present invention; Figure 7 This is a welding quality effect diagram of the present invention; Figure 8 This is a welding parameter data diagram of the present invention.

[0015] In the figure: adjusting bracket 1, supporting column 101, top plate 102, supporting bolt 103, first threaded hole 104, locking bolt 105, lower base 2, upper base 3, end cover 4, side plate 401, first connecting bolt 402, mounting plate 403, strip hole 404, nuclear power pile internal component 5, adjusting block 6, pressing block 601, clamping plate 602, tightening bolt 603, second threaded hole 604, adjusting hole 605, second connecting bolt 606, laser collimator 7, level 8. DETAILED DESCRIPTION

[0016] like Figure 1 As shown, a laser welding process for the upper guide tube of a nuclear power reactor internal component, the process uses a tool for assisting the welding of a semi-square tube, including an adjustment bracket 1, an upper base 3, a lower base 2 and an end cover 4, the top of the adjustment bracket 1 is movably connected to the lower end surface of the lower base 2, the upper base 3 and the lower base 2 are symmetrically arranged along the axis, the upper base 3 and the lower base 2 are connected to the end cover 4 at the front and rear ends, the nuclear power reactor internal component 5 is placed between the upper base 3 and the lower base 2 during welding, and a plurality of adjustment blocks 6 are arranged in parallel on the upper base 3 and the lower base 2; The main structure of the nuclear power pile internal component 5 is composed of two semi-square tubes, each with a weld on both sides. There are parts inside the nuclear power pile internal component 5. The nuclear power pile internal component 5 needs to be placed horizontally during welding. During welding, it is necessary to ensure that the weld has a high level so that the welding robot can complete the welding in one time. During welding, the workpiece needs to be pressurized to reduce welding deformation. Therefore, the nuclear power pile internal component 5 is placed between the upper base 3 and the lower base 2, and is pressurized and tightened by the adjustment block 6 to ensure the overall levelness of the weld.

[0017] The preferred solution is Figure 2 and Figure 3 As shown, the adjustment bracket 1 includes a support column 101, a top plate 102 and a support bolt 103; the top of the support column 101 is vertically connected to the top plate 102, the support bolt 103 is threadedly connected to the top plate 102, and the lower base 2 is placed on the support bolt 103; the lower end surfaces of the top plate 102 and the lower base 2 are correspondingly provided with a first threaded hole 104, and the locking bolt 105 is threadedly connected to the first threaded hole 104 and locks the position of the lower base 2 and the top plate 102; During the installation process, first adjust the overall height of the support bolt 103 by rotating the support bolt 103 so that the upper end surface of the adjustment bracket 1 remains at the same level. After the support bolt 103 is adjusted, place the lower base 2 on the support bolt 103, and lock the adjustment bracket 1 and the lower base 2 together through the locking bolt 105 to ensure the stability of the device.

[0018] The preferred solution is Figure 4As shown, the adjustment block 6 includes a pressure block 601, a clamping plate 602, a clamping bolt 603 and a second connecting bolt 606; the upper base 3 and the lower base 2 are equidistantly provided with adjustment holes 605, the pressure block 601 is placed in the adjustment hole 605, a clamping plate 602 is arranged above the pressure block 601, both sides of the top plate 102 are threadedly connected with the upper base 3 and the lower base 2 through the second connecting bolt 606, a second threaded hole 604 is opened at the center of the clamping plate 602, the clamping bolt 603 is threadedly connected with the second threaded hole 604 and abuts against the pressure block 601; During the welding process, when it is detected that the weld is tilted downward, the adjustment block 6 on the lower base 2 can be adjusted. By rotating the tightening bolt 603 and pushing the pressing block 601 upward, the workpiece weld can be adjusted upward. Conversely, when it is detected that the weld is tilted upward, the workpiece weld can be adjusted downward by rotating the tightening bolt 603 and pushing the pressing block 601 downward.

[0019] The preferred solution is Figure 5 As shown, the end cover 4 includes a side plate 401, and strip holes 404 are opened at the ends of the upper base 3 and the lower base 2. The first connecting bolt 402 passes through the strip hole 404 and is threadedly connected to the side of the side plate 401; by setting the strip hole 404, the position of the upper base 3 and the lower base 2 can be fine-tuned up and down, thereby ensuring the horizontality of the upper base 3 and the lower base 2.

[0020] The preferred solution is Figure 5 As shown, the side of the side plate 401 is fixedly connected to the mounting plate 403, and a laser collimator 7 is vertically installed on the mounting plate 403. The laser collimator 7 can project a horizontal collimation line at the weld to facilitate observation of the horizontality of the weld of the nuclear power pile internal component 5.

[0021] The preferred solution is Figure 5 As shown, a level 8 is installed at the upper end surface of the upper base 3, and the horizontality of the upper base 3 can be accurately judged by observing the level 8.

[0022] Embodiment: Welding a nuclear power reactor internal component 5, whose length is 2402mm; S1. Adjust the height of the bracket; S1.1. Place the adjustment bracket 1 on the workbench, and adjust the height of the support column 101 by rotating the support bolt 103 so that the upper end surface of the adjustment bracket 1 remains on the same horizontal plane; S1.2. Use a level to check whether the upper end surface of the adjustment bracket 1 is level. If necessary, continue to adjust the support bolts 103 until it is completely level. S1.3. Finally, use the locking bolts 105 to fix the lower base 2 on the supporting bolts 103 to ensure that the lower base 2 is on the same horizontal plane; S2. Placement of nuclear power reactor internals; S2.1. Place the nuclear power reactor internals 5 in the lower base 2, ensuring that the two half square tubes of the component are aligned and fit tightly; S2.2, buckle the upper base 3 onto the lower base 2, so that the nuclear power reactor internals 5 are located between the upper base 3 and the lower base 2; S3. Connect the end cover and pre-tighten it; S3.1. Connect the end caps 4 on both sides to the upper base 3 and the lower base 2, ensuring that the side panels 401 of the end caps 4 are aligned with the ends of the upper base 3 and the lower base 2; S3.2, use the first connecting bolt 402 to pass through the strip hole 404, and preliminarily tighten the end cover 4 to preliminarily fix the upper base 3 and the lower base 2 together; S4. Adjust the position of the upper base; S4.1. Ensure the levelness between the upper base 3 and the lower base 2 by adjusting the position of the upper base 3; S4.2. Use the level 8 to check the levelness of the upper base 3. If necessary, fine-tune the position of the upper base 3 through the strip hole 404. S4.3. After adjustment, tighten the end cover 4 for a second time to ensure that the upper base 3 and the lower base 2 are firmly fixed; S5. Adjust the levelness of the weld; S5.1. Check whether the welds of the nuclear power reactor internals 5 are on the same horizontal plane, and use a laser collimator 7 to project a horizontal collimation line at the weld to facilitate observation of the horizontality of the weld; S5.2. If the horizontality of the weld needs to be adjusted, rotate the clamping bolt 603 to push the pressing block 601 upward or downward to adjust the position of the weld until the weld is completely horizontal; S5.3. After confirming the horizontality of the weld, check again whether all fasteners are secure; S6, welding is performed; S6.1. Start the laser welding equipment, and first perform laser spot welding and fixation according to the preset welding parameters (such as laser power, welding speed, etc.), and then perform laser penetration welding; During the welding process, shielding gas is used. There are 10 spot welds, each section is about 50mm. If the number of spot welds is small, undercut may occur in deep penetration welding. Deep penetration welding can be used to weld the entire strip. The welding parameters are as follows: Figure 8 As shown; S6.2. During the welding process, the welding status is monitored in real time by a laser collimator 7 and other equipment to ensure the quality of the weld. After the welding is completed, the laser welding equipment is turned off, the end cover 4 and the upper base 3 are disassembled, and the welded nuclear power reactor internals 5 are taken out; S7, post-welding inspection; S7.1. Conduct a comprehensive quality inspection of welds using methods such as ultrasonic testing to ensure that the welds are free of defects and meet relevant standard requirements; S7.2. If any problems are found, the weld should be repaired or re-welded until it meets the qualified standards.

[0023] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from all points of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention; any reference numerals in the claims should not be regarded as limiting the claims involved.

Claims

1. A laser welding process for the upper guide tube of a nuclear power reactor internal component, characterized in that: The process uses a tool for assisting the welding of a semi-square tube, the tool comprising an adjustment bracket (1), an upper base (3), a lower base (2) and an end cover (4), the top of the adjustment bracket (1) is movably connected to the lower end surface of the lower base (2), the upper base (3) and the lower base (2) are symmetrically arranged along an axis, the end cover (4) is connected to the front and rear ends of the upper base (3) and the lower base (2), the nuclear power pile internal component (5) is placed between the upper base (3) and the lower base (2) during welding, and a plurality of adjustment blocks (6) are arranged in parallel on the upper base (3) and the lower base (2); The welding process includes the following steps: S1. Adjust the height of the adjustment bracket (1) so that the lower base (2) is on the same horizontal plane; S2, placing the nuclear power reactor internals (5) in the lower base (2), and buckling the upper base (3) onto the lower base (2); S3, connecting the end covers (4) on both sides to the upper base (3) and the lower base (2), and pre-tightening the end covers (4); S4. Adjust the upper base (3) to keep the upper base (3) level with the lower base (2). After the adjustment is completed, tighten the end cover (4) for a second time. S5, adjusting the adjusting blocks (6) on the upper base (3) and the lower base (2) so that the welds of the nuclear power pile internal components (5) are on the same horizontal plane; S6. Welding the welds of the nuclear power reactor internal components (5).

2. The laser welding process for the upper guide tube of the nuclear power reactor internal component according to claim 1 is characterized in that: The adjustment bracket (1) comprises a support column (101), a top plate (102) and a support bolt (103); the top of the support column (101) is vertically connected to the top plate (102), the support bolt (103) is threadedly connected to the top plate (102), and the lower base (2) is placed on the support bolt (103).

3. The laser welding process for the upper guide tube of the nuclear power reactor internal component according to claim 2 is characterized in that: The top plate (102) and the lower end surfaces of the lower base (2) are provided with first threaded holes (104) respectively, and the locking bolts (105) are threadedly connected to the first threaded holes (104) to lock and fix the positions of the lower base (2) and the top plate (102).

4. The laser welding process for the upper guide tube of the nuclear power reactor internal component according to claim 1 is characterized in that: The adjustment block (6) comprises a pressure block (601), a clamping plate (602), a clamping bolt (603) and a second connecting bolt (606); the upper base (3) and the lower base (2) are provided with adjustment holes (605) at equal intervals, the pressure block (601) is placed in the adjustment hole (605), a clamping plate (602) is arranged above the pressure block (601), both sides of the top plate (102) are threadedly connected to the upper base (3) and the lower base (2) via the second connecting bolt (606), a second threaded hole (604) is provided at the center of the clamping plate (602), the clamping bolt (603) is threadedly connected to the second threaded hole (604) and abuts against the pressure block (601).

5. The laser welding process for the upper guide tube of the nuclear power reactor internal component according to claim 1 is characterized in that: The end cover (4) comprises a side plate (401), and the ends of the upper base (3) and the lower base (2) are provided with strip holes (404). The first connecting bolt (402) passes through the strip hole (404) and is threadedly connected to the side of the side plate (401).

6. The laser welding process for the upper guide tube of the nuclear power reactor internal component according to claim 1 is characterized in that: The side portion of the side plate (401) is fixedly connected to the mounting plate (403), and a laser collimator (7) is vertically mounted on the mounting plate (403).

7. The laser welding process for the upper guide tube of the nuclear power reactor internal component according to claim 1 is characterized in that: A level (8) is installed on the upper end surface of the upper base (3).

8. The laser welding process for the upper guide tube of the nuclear power reactor internal component according to claim 1 is characterized in that: In S6, the nuclear power reactor internal component (5) is welded by first performing laser spot welding to fix it, and then performing laser penetration welding. The laser power of the spot welding section is controlled at about 2100W, and the laser power of the penetration welding section is controlled at about 2100W. Nitrogen is used as the shielding gas for welding, and the shielding gas flow rate is controlled at about 10-20L / min.

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