A positioning rib welding process for a nuclear power generator

Abstract

This invention provides a process for welding positioning ribs in a nuclear power generator, comprising the following steps: S1: Place the generator base horizontally on a platform and level it; S2: Mark the machining allowance line and hammer a punch; S3: Turn the generator base upside down, place it upright on the platform, and level it; S4: Install the positioning rib welding fixture according to the marked circular line in S2 and spot weld it in place; S5: Pull steel wires at the slots of the positioning rib welding fixtures at both ends of the generator base; S6: Weld the limiting round steel; S7: Remove the steel wires and hoist the positioning ribs in groups; S8: Adjust the positioning rib welding fixtures so that the positioning ribs are tightly attached to the limiting round steel; S9: Assemble the support blocks and spot weld them in place; S10: Use a 3D laser scanner to detect the position and dimensions of the positioning ribs and record the data; S11: Weld in sequence, and perform flat welding on all welds; S12: Grind the welds and perform 100% flaw detection. S13: Remove the positioning rib welding fixture, and finally use a 3D laser scanner to detect the position and size of the positioning rib, and record it for future reference.

Description

Technical Field

[0001] This invention belongs to the field of generator base technology, and specifically relates to a welding process for positioning ribs of a nuclear power generator. Background Technology

[0002] In the nuclear power field, near-stringent requirements are placed on the safety, reliability, and long-term operation of generators. Even the smallest manufacturing defect can lead to serious consequences. The accuracy of the stator core mounting reference surface directly determines core electromagnetic performance parameters such as the uniformity of the electromagnetic field and the symmetry of the air gap within the generator. The positioning ribs in the generator mount, as key basic components for fixing the stator core laminations, have a decisive influence on the final forming quality of the core due to their installation position and geometric accuracy (such as chord pitch uniformity, perpendicularity, and roundness).

[0003] Traditional welding processes rely on manual marking, positioning, and spot welding for fixation. Manual operation makes it difficult to accurately guarantee the chord spacing, radial position, and perpendicularity of the positioning ribs, failing to meet the extremely high requirements of nuclear power generators for core roundness and air gap uniformity. Furthermore, if subsequent inspections reveal deviations in chord spacing, perpendicularity, or roundness after initial spot welding of the positioning ribs, the original spot welds must be destructively removed and repositioned and spot welded. This is not only inefficient but also increases the risk of deformation, damages the substrate, and leads to decreased electromagnetic performance, excessive noise, and reduced reliability throughout the decades-long design life of the nuclear power generator.

[0004] Therefore, the above problems urgently need to be solved. Summary of the Invention

[0005] Purpose of the Invention: To overcome the above shortcomings, this invention provides a welding process for positioning ribs in nuclear power generators. This process involves a flip-over flat welding method, ensuring the generator base is vertical during welding, controlling base deformation, and installing the positioning ribs in batches to ensure their verticality. This prevents uneven stress on the generator base during assembly, which could lead to deformation. A limiting round steel bar provides a positioning reference for the positioning ribs, improving assembly convenience and accuracy. Combined with positioning rib welding fixtures, the chord pitch and radial dimensions of the positioning ribs are adjusted to ensure proper chord pitch and roundness, thereby ensuring generator assembly accuracy and guaranteeing the generator's electromagnetic performance, noise levels, and reliability during long-term operation.

[0006] Technical Solution: To achieve the above objectives, this invention provides a welding process for positioning ribs in nuclear power generators, comprising the following steps:

[0007] S1: Place the machine base horizontally on the platform and level it. Use a level to adjust the horizontality of the machine base to <0.1mm and the verticality of the machine base end face to <0.03mm. This step is the starting point of the process; strict limits are placed on the horizontality and verticality to ensure the accuracy of subsequent welding.

[0008] S2: Draw machining allowance lines and hammer a center punch. Based on the axial center of the machine base, draw a segmental circle line on the side wall of the ring plate and hammer a cross center line center punch. The machine base has a machining allowance at its axial center. After the positioning ribs and machine base are welded together, the machine base is machined to reduce the impact of welding deformation and ensure the chord spacing, perpendicularity, or roundness of the positioning ribs. The axial center of the machine base can be determined by measuring the center of the upper and lower end plates of the machine base using a 3D laser scanner.

[0009] S3: Flip the machine base so that the excitation end faces down, place the machine base upright on the platform and level it. Use a level to adjust the horizontality of the machine base end face to <0.1mm and the verticality of the machine base base plane to <0.03mm. Place the machine base in a vertical position and weld the positioning ribs. This can reduce the influence of gravity on the positioning ribs, ensure the straightness of the positioning ribs, improve the positioning accuracy of the positioning ribs, and reduce the difficulty of subsequent adjustments.

[0010] S4: Install the positioning rib welding fixture according to the segment circle line drawn in S2 and spot weld it in place. The positioning rib welding fixture includes a radial adjusting bolt group and a circumferential adjusting bolt group. The radial adjusting bolt group is used to adjust the radial dimension of the positioning rib, and the circumferential adjusting bolt group is used to adjust the chord distance of the positioning rib. The center of the machine base can be determined according to the segment circle line drawn in S2. The positioning rib welding fixture is installed along the segment circle line so that after installation, the positioning rib welding fixture is positioned around the center of the machine base, and all positioning rib fixtures are equidistant from the center of the machine base. The chord distance and radial dimension of the positioning rib are adjusted by the radial adjusting bolt group and the circumferential adjusting bolt group. To prevent the positioning rib welding fixture from moving, it is spot welded to the ring plate in place.

[0011] S5: A steel wire is pulled at the slot of the welding fixture with positioning ribs at both ends of the machine base. The steel wire provides a reference for the subsequent welding of the limiting round steel. The two ends of the steel wire are fixed to the two ends of the machine base and tightened with a fixing tool to reduce deflection error.

[0012] S6: Install and weld the limiting round steel. The limiting round steel is attached to the side wall of the ring plate, and is positioned perpendicular to the bottom of the slot provided in the ring plate. The end face of the limiting round steel is in partial contact with the steel wire. The limiting round steel and the steel wire are in contact and welded to the side wall of the ring plate, so that the limiting round steel is arranged along the axial reference formed by the steel wire. This transforms the linear reference formed by the steel wire into the surface reference formed by the limiting round steel, providing an installation reference for the installation of the positioning rib.

[0013] S7: Remove the steel wire, hoist the positioning ribs in groups, and adjust the height of the positioning ribs so that the upper end of the positioning rib is flush with the inner side of the upper end plate of the machine base. Hoist the positioning ribs in groups to balance the force on the machine base, avoid eccentric deformation, and use positioning rib welding fixtures to fix the positioning ribs.

[0014] S8: Adjust the positioning rib welding fixture to ensure the positioning rib is tightly against the limiting round steel. Adjusting the positioning rib fixture to ensure the positioning rib is tightly against the limiting round steel can be checked using a feeler gauge; the gap between the positioning rib and the limiting round steel should be ≤0.05mm.

[0015] S9: Assemble the support block and spot weld it in place. Use the support block to connect the positioning rib and the ring plate, fixing the positioning rib in place and preventing it from shifting during subsequent testing, thus improving testing accuracy and efficiency.

[0016] S10: Use a 3D laser scanner to check the position and dimensions of the positioning ribs. The position and dimension error of the positioning ribs should be ≤2mm, and a record should be kept. Check the position and dimensions of the positioning ribs before welding to ensure dimensional accuracy before welding.

[0017] S11: Weld in sequence, and perform flat welding on all weld seams.

[0018] S12: Repair and grind the weld seam and perform 100% flaw detection. Magnetic particle testing is used for flaw detection; welds that fail the test must be repaired.

[0019] S13: Remove the welding fixture for the positioning ribs, and finally use a 3D laser scanner to check the position and size of the positioning ribs. Confirm that the position and size error of the positioning ribs is ≤2mm, and record it for future reference.

[0020] Furthermore, in the above-mentioned nuclear power generator positioning rib welding process, step S2, which involves marking machining allowance lines and hammering samples, includes the following steps:

[0021] S2-1: Draw the top support allowance line and tap the punch.

[0022] S2-2: Draw the allowance line on the bottom plane and tap the punch.

[0023] S2-3: Draw the bottom support allowance line and tap the punch.

[0024] S2-4: Draw the cross center line of the determined machine base axial center line to the outer wall end face and tap it.

[0025] S2-5: Draw pitch circle lines on the steam end and exciter end according to the axial center line of the machine base and strike the cross center line punch.

[0026] Furthermore, in the above-mentioned nuclear power generator positioning rib welding process, step S5 includes: suspending the steel wire in the corresponding indexing slots at the steam end and excitation end, aligning it with the center of the slot, fixing and tightening the steel wire using a steel wire fixing tool, and determining the center line of the slot from the steam end to the excitation end.

[0027] Furthermore, in the above-mentioned nuclear power generator positioning rib welding process, in step S7, the positioning ribs are divided into six groups of four diagonally opposite each other and hoisted into the base from the top of the base.

[0028] Furthermore, in the above-mentioned nuclear power generator positioning rib welding process, step S8, adjusting the positioning rib welding fixture includes:

[0029] S8-1: Adjust the circumferential adjusting bolt group installed by the welding machine to adjust the chord spacing of the positioning rib.

[0030] S8-2: Adjust the radial adjustment bolt group installed by the welding machine to adjust the radial dimension and verticality of the positioning rib. The radial adjustment bolt group, together with the wedge, adjusts the radial dimension of the positioning rib. Specifically, when the distance between the positioning rib and the center of the machine base is too large, tighten the radial adjustment bolt; when the distance between the positioning rib and the center of the machine base is too small, insert the wedge between the positioning rib and the groove of the ring plate.

[0031] S8-3: Check the gap between the positioning rib and the limiting round steel 7, ensure that the positioning rib is tightly attached to the limiting round steel, and tighten the radial adjusting bolt group and the circumferential bolt group.

[0032] Furthermore, in the above-mentioned nuclear power generator positioning rib welding process, in step S9, the assembly of the support block includes:

[0033] S9-1: Recheck the position and dimensions of the positioning ribs, and adjust the positioning rib welding fixture to ensure that the position and dimension error of the positioning ribs is ≤2mm.

[0034] S9-2: Install the support block on the upper surface of the middle ring, and spot weld it in place after the support block is close to the positioning rib.

[0035] Furthermore, in the above-mentioned nuclear power generator positioning rib welding process, step S11 includes the following steps:

[0036] S11-1: With the excitation end facing down, perform flat welding on all seams sequentially from the middle to both ends. During the welding process, the welder is allowed to use wedges; after the wedges are embedded in the gaps, seal them with weld. After welding is completed in this step, remove the positioning rib fixture and install welding support blocks on the upper side of all ring plates.

[0037] S11-2: Turn the machine base over so that the steam end faces downwards, and weld all seams sequentially from the middle to both ends. During this step, welding supports are installed on the upper side of the ring plate. Turning the machine base over for welding ensures it remains vertical, and using flat welding guarantees penetration and weld quality. Turning the machine base over reduces thermal deformation and controls the amount of deformation. Welding from the middle to both ends allows heat to dissipate rapidly along the welding direction, resulting in better heat dissipation from the steel plate, reducing heat accumulation in the middle, and distributing stress more evenly on both sides of the weld. This reduces deformation caused by stress concentration, thus lowering the degree of deformation.

[0038] S11-3: Use a retaining ring to re-measure the position of the screws at both ends of the positioning rib, and use a heat gun to fine-tune the position of the screws at both ends of the positioning rib. Locally heat the positioning rib to release stress and correct the screw position. The retaining ring is an arc-shaped plate with through holes corresponding to the screw positions. The positional accuracy between the screws is checked by inserting the screws into the through holes.

[0039] Further, in the above-mentioned nuclear power generator positioning rib welding process, step S11 includes the following steps: S11-4: Adjusting the center line. The original base center line is determined using the pitch circle line reserved in step S2. A square steel is placed on the upper end of the base, and a plumb line is tied to the square steel. The plumb line is aligned with the original base center line, and the current base center line is determined by the actual position of the positioning rib after welding. The deviation between the current base center line and the original base center line is detected, and the original base center line is adjusted so that the positional dimensional error of the positioning rib is <2mm, thus determining the final base center line. By comparing the deviation between the original base center line and the current base center line, the original base center line is adjusted so that the dimensional error of the positioning rib meets the requirements. The adjusted original base center line is the final base center line, at which point the dimensional error of the positioning rib from the final base center line is <2mm.

[0040] Furthermore, in the above-mentioned nuclear power generator positioning rib welding process, the machining allowance line drawn in step 2 is ground off, and the machining allowance line is redrawn with the final base center line to provide a reference for subsequent processing, so that the finishing process can adapt to welding deformation and ensure assembly accuracy.

[0041] Furthermore, in the above-mentioned nuclear power generator positioning rib welding process, if the deviation between the original base centerline and the current base centerline is <2mm, there is no need to adjust the original base centerline, and the machining allowance line does not need to be redrawn.

[0042] Furthermore, in the above-mentioned nuclear power generator positioning rib welding process, if any positioning rib is out of tolerance and difficult to adjust, the positioning rib weld is separated, and the positioning rib position coordinates are adjusted again using positioning rib welding fixtures to meet the tolerance range before re-welding.

[0043] Furthermore, in the aforementioned nuclear power generator positioning rib welding process, the threaded section of the positioning rib is protected at the end, and the base is sandblasted, cleaned, and painted.

[0044] Furthermore, in the aforementioned nuclear power generator positioning rib welding process, the inner side of the ring plate has slots arranged along the center array. Steel wires pass through the slots and are fixed to the end plates at both ends of the base. The steel wires are tightened and straightened. One end of the limiting round steel extends into the slot and abuts against the steel wires. The limiting round steel is spot-welded to the side wall of the ring plate.

[0045] Furthermore, in the aforementioned nuclear power generator positioning rib welding process, the positioning rib welding fixture includes an arc-shaped plate, which includes a base plate and a first end plate and a second end plate welded to both ends of the base plate. The first end plate and the second end plate are respectively threaded with circumferential adjusting bolts, which together form a circumferential adjusting bolt group. The circumferential adjusting bolts connected to the first end plate and the second end plate respectively abut against the upper and lower sides of the positioning rib, and the chord spacing of the positioning rib is adjusted by turning the circumferential adjusting bolts. The base plate is connected with radial adjusting bolts, and multiple radial adjusting bolts connected to the base plate form a radial adjusting bolt group. The radial adjusting bolts abut against the side of the positioning rib near the center of the base, and adjust the distance between the positioning rib and the centerline of the base. The first end plate and the second end plate are respectively provided with notches, and locking bolts are connected to the sidewalls of the notches. A ring plate is inserted into the notch, and the locking bolts abut against the sidewalls of the ring plate, connecting the positioning rib welding fixture and the ring plate.

[0046] As can be seen from the above technical solution, the present invention has the following beneficial effects: The nuclear power generator positioning rib welding process of the present invention, through a two-stage flipping flat welding process, ensures that the base is in a vertical state during welding, controls base deformation, and hoists the positioning ribs in batches to ensure the verticality of the positioning ribs, avoiding uneven stress on the base during the positioning rib assembly process and preventing base deformation. The use of limiting round steel to provide a positioning reference for the positioning ribs improves the convenience and accuracy of assembly. Combined with the positioning rib welding fixture, the chord pitch and radial dimensions of the positioning ribs are adjusted to ensure the chord pitch and roundness of the positioning ribs, ensuring the generator assembly accuracy, and ensuring the generator's electromagnetic performance, noise index, and reliability during long-term operation. Attached Figure Description

[0047] Figure 1 This is a flowchart of the nuclear power generator positioning rib welding process of the present invention.

[0048] Figure 2 This is a schematic diagram of the mechanism of the base.

[0049] Figure 3 This is a schematic diagram of the positioning rib being hoisted into the machine base.

[0050] Figure 4 This is a schematic diagram of the installation of the limiting round steel.

[0051] Figure 5 This is a structural schematic diagram of the positioning rib welding fixture.

[0052] Figure 6 The diagram shows the installation of the positioning rib welding fixture on the ring plate and the connection of the positioning rib.

[0053] In the diagram: 1. Base, 2. Positioning rib, 6. Steel wire, 7. Limiting round steel, 8. Ring plate, 81. Groove, 91. Base plate, 92. First end plate, 93. Second end plate, 94. Circumferential adjusting bolt, 95. Radial adjusting bolt, 96. Notch, 97. Locking bolt. Detailed Implementation

[0054] Example

[0055] like Figure 1-3 The process for welding positioning ribs in a nuclear power generator, as shown, includes the following steps:

[0056] S1: Place the base 1 horizontally on the platform and level it. Use a level to adjust the horizontality of the base 1 to <0.1mm and the verticality of the end face of the base 1 to <0.03mm. Placing the base 1 horizontally on the platform and leveling it with a level ensures the horizontality and verticality of the base 1. This step is the starting point of the process, and the horizontality and verticality are strictly limited to ensure the accuracy of subsequent welding.

[0057] S2: Draw machining allowance lines and hammer a center punch. Based on the axial center of the machine base 1, draw a segmented circle line on the side wall of the ring plate and hammer a cross center line center punch. The machine base 1 has a machining allowance at its axial center. After the positioning rib 2 and the machine base 1 are welded together, the machine base 1 is then machined to reduce the impact of welding deformation and ensure the chord spacing, perpendicularity, or roundness of the positioning rib 2. The axial center of the machine base 1 can be determined by measuring the center of the upper and lower end plates of the machine base 1 using a 3D laser scanner.

[0058] S3: Flip the base 1 so that the excitation end faces down, place the base 1 upright on the platform and level it. Use a level to adjust the horizontality of the end face of the base 1 to <0.1mm and the verticality of the base 1's base plane to <0.03mm. Place the base 1 in a vertical position and weld the positioning rib 2. This reduces the influence of gravity on the positioning rib 2, ensures the straightness of the positioning rib 2, improves the positioning accuracy of the positioning rib 2, and reduces the difficulty of subsequent adjustments.

[0059] S4: Install the positioning rib welding fixture according to the segment circle line drawn in S2 and spot weld it in place. The positioning rib welding fixture includes a radial adjusting bolt group and a circumferential adjusting bolt group. The radial adjusting bolt group is used to adjust the radial dimension of the positioning rib 2, and the circumferential adjusting bolt group is used to adjust the chord distance of the positioning rib 2. The center of the machine base 1 can be determined according to the segment circle line drawn in S2. The positioning rib welding fixture is installed along the segment circle line so that after installation, the positioning rib welding fixture is positioned around the center of the machine base 1, and all positioning rib fixtures are equidistant from the center of the machine base 1. The chord distance and radial dimension of the positioning rib 2 are adjusted by the radial adjusting bolt group and the circumferential adjusting bolt group. To prevent the positioning rib welding fixture from moving, it is spot welded to the ring plate in place.

[0060] S5: A steel wire 6 is pulled at the slot of the welding fixture with positioning ribs at both ends of the machine base 1. The steel wire 6 provides a reference for the subsequent welding of the limiting round steel 7. The two ends of the steel wire 6 are fixed to the two ends of the machine base 1 respectively, and tightened with a fixing tool to reduce deflection error.

[0061] S6: Install and weld the limiting round steel 7. The limiting round steel 7 is attached to the side wall of the ring plate and is perpendicular to the bottom of the slot provided in the ring plate. The end face of the limiting round steel 7 is in partial contact with the steel wire 6. The limiting round steel 7 is in contact with the steel wire and welded to the side wall of the ring plate, so that the limiting round steel 7 is arranged along the axial reference formed by the steel wire, transforming the linear reference formed by the steel wire into the surface reference formed by the limiting round steel 7, providing an installation reference for the installation of the positioning rib 2.

[0062] S7: Remove steel wire 6, hoist positioning ribs 2 in groups, adjust the height of positioning ribs 2 so that the upper end of positioning ribs 2 is flush with the inner side of the upper plate of the machine base 1. Hoist positioning ribs 2 in groups to balance the force on the machine base 1, avoid eccentric deformation, and use positioning rib welding fixtures to fix positioning ribs 2.

[0063] S8: Adjust the positioning rib welding fixture to make the positioning rib 2 tightly attached to the limiting round steel 7. Adjust the positioning rib fixture to make the positioning rib 2 tightly attached to the limiting round steel 7. The gap between the positioning rib 2 and the limiting round steel 7 can be checked using a feeler gauge and found to be ≤0.05mm.

[0064] S9: Assemble the support block and spot weld it in place. Use the support block to connect the positioning rib 2 and the ring plate, fixing the positioning rib 2 in place and preventing it from shifting during subsequent testing, thus improving testing accuracy and efficiency.

[0065] S10: Use a 3D laser scanner to check the position and dimensions of positioning rib 2. The position and dimension error of positioning rib 2 should be ≤2mm, and a record should be made. Check the position and dimensions of positioning rib 2 before welding to ensure dimensional accuracy before welding.

[0066] S11: Weld in sequence, and perform flat welding on all weld seams.

[0067] S12: Repair and grind the weld seam and perform 100% flaw detection. Magnetic particle testing is used for flaw detection; welds that fail the test must be repaired.

[0068] S13: Remove the welding fixture for the positioning ribs, and finally use a 3D laser scanner to check the position and size of positioning rib 2. Confirm that the position and size error of positioning rib 2 is ≤2mm, and record it for future reference.

[0069] The step S2, which involves marking the machining allowance line and hammering the sample punch, includes the following steps:

[0070] S2-1: Draw the top support allowance line and tap the punch.

[0071] S2-2: Draw the allowance line on the bottom plane and tap the punch.

[0072] S2-3: Draw the bottom support allowance line and tap the punch.

[0073] S2-4: Draw the cross center line of the determined axial center line of the base 1 onto the outer wall end face and tap it.

[0074] S2-5: Draw pitch circle lines on the steam end and exciter end according to the axial center line of the machine base 1, and then tap the cross center line punch.

[0075] Step S5 includes: suspending the steel wire in the corresponding indexing slots at the steam end and the exciter end, aligning it with the center of the slot, fixing and tightening the steel wire using a steel wire fixing tool, and determining the center line of the slot from the steam end to the exciter end.

[0076] In step S7, the positioning ribs 2 are divided into six groups of four diagonally opposite each other and hoisted into the machine base 1 from the top of the machine base 1.

[0077] In step S8, adjusting the positioning rib welding fixture includes:

[0078] S8-1: Adjust the circumferential adjusting bolt group installed by the welding worker to adjust the chord distance of the positioning rib 2.

[0079] S8-2: Adjust the radial dimension and perpendicularity of the positioning rib 2 using the radial adjusting bolt group installed by the welding machine. The radial adjusting bolt group, in conjunction with the wedge, adjusts the radial dimension of the positioning rib 2. Specifically, when the distance between the positioning rib 2 and the center of the machine base 1 is too large, tighten the radial adjusting bolt; when the distance between the positioning rib 2 and the center of the machine base 1 is too small, insert the wedge between the positioning rib and the groove of the ring plate.

[0080] S8-3: Check the gap between the positioning rib 2 and the limiting round steel 7, ensure that the positioning rib 2 is tightly attached to the limiting round steel 7, and tighten the radial adjusting bolt group and the circumferential bolt group.

[0081] In step S9, assembling the support block includes:

[0082] S9-1: Recheck the position dimensions of positioning rib 2, and adjust the positioning rib welding fixture to ensure that the position dimension error of the positioning rib is ≤2mm.

[0083] S9-2: Install the support block on the upper surface of the middle ring, and spot weld it to the positioning rib 2 after the support block is close to it.

[0084] Step S11 includes the following steps:

[0085] S11-1: With the excitation end facing down, perform flat welding on all seams sequentially from the middle to both ends. During the welding process, the welder is allowed to use wedges; after the wedges are embedded in the gaps, seal them with weld. After welding is completed in this step, remove the positioning rib fixture and install welding support blocks on the upper side of all ring plates.

[0086] S11-2: Turn the base 1 over so that the steam end faces downwards, and perform flat welding on all seams sequentially from the middle to both ends. During this step, welding support blocks are installed on the upper side of the ring plate. Turning the base 1 over for welding ensures that it remains vertical, and flat welding is used to ensure penetration depth and weld quality. Turning the base over reduces thermal deformation and controls the amount of deformation. Welding from the middle to both ends allows heat to diffuse rapidly along the welding direction, resulting in better heat dissipation from the steel plate, reducing heat accumulation in the middle, and distributing stress more evenly on both sides of the weld, reducing deformation caused by stress concentration, and thus lowering the degree of deformation.

[0087] S11-3: Use a retaining ring to re-measure the position of the screws at both ends of positioning rib 2, and use a heat gun to fine-tune the position of the screws at both ends of positioning rib 2. Locally heat positioning rib 2 to release stress and correct the screw position. The retaining ring is an arc-shaped plate with through holes corresponding to the screw positions. The positional accuracy between the screws is checked by inserting the screws into the through holes.

[0088] Step S11 includes step S11-4: Adjusting the center line. The original center line of the base 1 is determined using the pitch circle line reserved in step S2. A square steel bar is placed on the upper end of the base 1, and a plumb line is tied to the square steel bar. The plumb line is aligned with the original center line of the base 1. The current center line of the base 1 is determined by the actual position of the positioning rib 2 after welding. The deviation between the current center line of the base 1 and the original center line of the base 1 is detected. The original center line of the base 1 is adjusted so that the positional dimensional error of the positioning rib 2 is <2mm, thus determining the final center line of the base 1. By comparing the deviation between the original center line of the base 1 and the current center line of the base 1, the original center line of the base 1 is adjusted so that the dimensional error of the positioning rib 2 meets the requirements. The adjusted original center line of the base 1 is the final center line of the base 1, at which point the dimensional error of the positioning rib 2 from the final center line of the base 1 is <2mm.

[0089] The machining allowance lines drawn in step 2 are ground off, and the machining allowance lines are redrawn with the final center line of the machine base 1 to provide a reference for subsequent machining, so that the finishing process can adapt to welding deformation and ensure assembly accuracy.

[0090] If the deviation between the original center line of machine base 1 and the current center line of machine base 1 is less than 2mm, there is no need to adjust the original center line of machine base 1, and there is no need to redraw the machining allowance line.

[0091] If the positioning rib 2 is out of tolerance and difficult to adjust, separate the positioning rib weld, re-adjust the positioning rib position coordinates using the positioning rib welding fixture, and re-weld it after it meets the tolerance range.

[0092] Finally, the threaded section of the positioning rib 2 is protected, and the machine base 1 is sandblasted, cleaned, and painted.

[0093] like Figure 4The limiting round steel 7 is shown in the welding state. The inner side of the ring plate 8 has slots 81 arranged along the center. The steel wire 6 passes through the slots 81 and is fixed to the end plates at both ends of the base 1. The steel wire 6 is tightened and straightened. One end of the limiting round steel 7 extends into the slot 81 and abuts against the steel wire 6. The limiting round steel 7 is spot welded to the side wall of the ring plate 8.

[0094] like Figure 5-6 The positioning rib welding fixture shown includes an arc-shaped plate, which includes a base plate and a first end plate 92 and a second end plate 93 welded to both ends of the base plate 91. The first end plate 92 and the second end plate 92 are respectively threaded with circumferential adjusting bolts 94, forming a circumferential adjusting bolt group. The circumferential adjusting bolts 94 connected to the first end plate 92 and the second end plate 92 respectively abut against the upper and lower sides of the positioning rib. Tightening the circumferential adjusting bolts 94 adjusts the chord spacing of the positioning rib. The base plate 91 is connected with radial adjusting bolts 95, which together form a radial adjusting bolt group. The radial adjusting bolts 95 abut against the side of the positioning rib closest to the center of the machine base 1, adjusting the distance between the positioning rib and the centerline of the machine base 1. The first end plate 92 and the second end plate 92 are respectively provided with notches 96. Locking bolts 97 are connected to the side walls of the notches 96. The ring plate is inserted into the notches 96, and the locking bolts 97 abut against the side walls of the ring plate, thus connecting the adjusting positioning rib welding fixture and the ring plate.

[0095] The above embodiments are exemplary and are intended to illustrate the technical concept and features of the present invention, so that those skilled in the art can understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A welding process for locating ribs in a nuclear power generator, characterized in that: Includes the following steps: S1: Place the base (1) horizontally on the platform and level the base (1). Use a level to adjust the horizontality of the base (1) to <0.1mm and the verticality of the end face of the base (1) to <0.03mm. S2: Draw machining allowance lines and tap the center punch. Draw a nodal circle line on the side wall of the ring plate according to the axial center of the machine base (1) and tap the center cross line. S3: Flip the base (1) so that the excitation end faces down, place the base (1) upright on the platform and level it, use a level to adjust the horizontality of the end face of the base (1) to <0.1mm, and adjust the verticality of the bottom plane of the base (1) to <0.03mm; S4: Install the positioning rib welding fixture according to the section circle line drawn in S2 and spot weld it in place; the positioning rib welding fixture includes a radial adjusting bolt group and a circumferential adjusting bolt group. The radial adjusting bolt group is used to adjust the radial dimension of the positioning rib (2), and the circumferential adjusting bolt group is used to adjust the chord distance of the positioning rib (2). S5: Steel wire (6) is pulled at the slot position of the welding fixture with positioning ribs at both ends of the machine base (1). S6: Welding the limiting round steel (7); The limiting round steel (7) is attached to the side wall of the ring plate, the limiting round steel (7) is set perpendicular to the bottom of the slot provided in the ring plate, and the end face of the limiting round steel (7) is in partial contact with the steel wire (6); S7: Remove the steel wire (6), hoist the positioning ribs (2) in groups, adjust the height of the positioning ribs (2) so that the upper end of the positioning ribs (2) is flush with the inner side of the upper plate of the machine base (1); S8: Adjust the positioning rib welding fixture so that the positioning rib (2) is tightly attached to the limiting round steel (7); S9: Assemble the support block and spot weld it in place; S10: Use a 3D laser scanner to check the size of the positioning rib (2). The size error of the positioning rib (2) is ≤2mm, and a record is kept. S11: Weld in sequence, and perform flat welding on all weld seams; S12: Grind the weld and perform 100% flaw detection; S13: Remove the positioning rib welding fixture, and finally use a three-dimensional laser scanner to check the size of the positioning rib (2), confirm that the size error of the positioning rib (2) is ≤2mm, and record it for future reference; In step S8, adjusting the positioning rib welding fixture includes: S8-1: Adjust the circumferential adjusting bolt group of the positioning rib installed by the welder to adjust the chord distance of the positioning rib (2); S8-2: Adjust the radial dimension and verticality of the positioning rib (2) by adjusting the radial adjusting bolt group installed by the welder; S8-3: Check the gap between the positioning rib (2) and the limiting round steel (7) to ensure that the positioning rib (2) is tightly attached to the limiting round steel (7), and tighten the radial adjusting bolt group and the circumferential bolt group.

2. The nuclear power generator positioning rib welding process according to claim 1, characterized in that: The step S2, which involves marking the machining allowance line and hammering the sample punch, includes the following steps: S2-1: Draw the top support allowance line and tap the punch; S2-2: Mark the allowance line on the bottom plane and tap the punch; S2-3: Draw the bottom support allowance line and tap the punch; S2-4: Draw the cross center line of the determined machine base (1) axial center line to the outer wall end face and tap it; S2-5: Draw a pitch circle on the steam end and exciter end according to the axial center line of the machine base (1) and strike the cross center line.

3. The nuclear power generator positioning rib welding process according to claim 1, characterized in that: Step S5 includes: suspending the steel wire (6) in the corresponding indexing slots of the steam end and the exciter end, aligning it with the center of the slot, fixing and tightening the steel wire with a steel wire fixing tool, and determining the center line of the slot from the steam end to the exciter end.

4. The nuclear power generator positioning rib welding process according to claim 1, characterized in that: In step S7, the positioning ribs (2) are divided into six groups of four diagonally opposite each other and hoisted into the machine base (1) from the top of the machine base (1) in sequence.

5. The nuclear power generator positioning rib welding process according to claim 1, characterized in that: In step S9, assembling the support block includes: S9-1: Recheck the dimensions of the positioning rib (2), and adjust the positioning rib welding fixture to ensure that the positioning rib dimension error is ≤2mm; S9-2: Install the support block on the upper surface of the middle ring, and spot weld the support block and the positioning rib (2) together.

6. The nuclear power generator positioning rib welding process according to claim 1, characterized in that: Step S11 includes the following steps: S11-1: With the excitation end facing down, weld all seams sequentially from the middle to both ends; S11-2: Turn the base (1) over so that the steam end is facing down, and weld all the welds from the middle to both ends in sequence.

7. The nuclear power generator positioning rib welding process according to claim 6, characterized in that: Step S11 includes the following steps: S11-3: Use a retaining ring to re-measure the position of the screws at both ends of the positioning rib (2), and use a fire torch to fine-tune the position of the screws at both ends of the positioning rib (2).

8. The nuclear power generator positioning rib welding process according to claim 1, characterized in that: Step S11 includes the following steps: S11-4: Adjust the center line; determine the original center line of the machine base (1) using the pitch circle line reserved in step S2; place a square steel on the upper end of the machine base (1), tie a vertical line on the square steel, and make the vertical line coincide with the center line of the original machine base (1). Determine the center line of the current machine base (1) based on the actual position of the positioning rib (2) after welding; check the deviation between the center line of the current machine base (1) and the center line of the original machine base (1), adjust the center line of the original machine base (1) so that the size error of the positioning rib (2) is <2mm, and determine the final center line of the machine base (1).

9. The nuclear power generator positioning rib welding process according to claim 8, characterized in that: Grind away the machining allowance line drawn in step 2, and redraw the machining allowance line with the center line of the final machine base (1).

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