A method for manufacturing an impact runner electroslag casting welding

Abstract

The application discloses a manufacturing method of an impact runner by electroslag casting and welding, and particularly relates to the following steps: the impact runner is split into spoke units and bucket units along a circumference, a wedge-shaped casting and welding groove is reserved on the circumference of the spoke units, and a trapezoidal connecting plate is reserved in the direction of a bucket root of the bucket units; a combined crystallizer and a consumable electrode are manufactured according to the structural features and the outer dimensions of the split spoke units and the bucket units; the spoke units are first subjected to block electroslag casting and welding, and then the spoke units are adjusted to vertical circumferential rotation; the combined crystallizer and the consumable electrode of the bucket units are clamped on the casting and welding groove, the first bucket unit is subjected to casting and welding, the spoke is rotated after the first bucket unit is subjected to casting and welding, the second bucket unit is subjected to casting and welding, and the like, until the casting and welding of all the bucket units are completed; and the overall manufacturing of the impact runner is completed through the casting and welding of the spoke units and the bucket units. The method has the advantages of improving material purity, reducing machining quantity, shortening a manufacturing period, improving the overall performance of the impact runner, reducing the difficulty of equipment and the like.

Description

Technical Field

[0001] This invention relates to the manufacturing process of impact wheels, and in particular provides a method for manufacturing impact wheels by electroslag casting and welding, which belongs to the field of near-net-shape forming manufacturing methods in the field of material hot working. Background Technology

[0002] With the further development of hydropower resources, the construction of large-scale high-head hydropower stations has become a development trend. Large-scale high-head hydropower stations are suitable for using impact runners as the core flow-through components of the generator units; currently, the largest outer diameter of impact runners reaches 8 meters. Among the manufacturing methods for impact runners, those manufactured by "integral sand casting" have uncontrollable microstructure, performance, and defects, and can only be applied to relatively low-head conditions. Runners manufactured by "integral forging + CNC machining" have better overall performance, but the manufacturing cost is high and exceeds the capacity limit of existing forging equipment (5m). "Separate assembly manufacturing" can significantly reduce manufacturing difficulty, lessen reliance on large equipment, improve the quality of individual components, and facilitate transportation.

[0003] Chinese invention patent publication number CN 104625650 A discloses a manufacturing process for an impact turbine runner, which obtains the finished runner through forging and robotic welding. Chinese invention patent publication number CN107119193 A discloses an additive manufacturing device based on electroslag remelting, belonging to the field of metal material manufacturing technology.

[0004] In summary, while the aforementioned methods for "split-assembly manufacturing" of impact wheels and the research on electroslag casting manufacturing equipment have many advantages, the electroslag casting and welding manufacturing technology for impact wheels has not been mentioned. Furthermore, because impact wheels are complex, irregularly shaped components, and electroslag casting and welding is a complex multi-field interaction forming process, many challenges still constrain the development of impact wheel manufacturing technology and electroslag casting and welding technology. These include equipment capacity issues for integral forging manufacturing, forming quality and production cycle issues for water tank parts manufactured using electric arc welding or robotic welding, forming accuracy issues for complex components manufactured by electroslag casting, and equipment capacity issues for producing large components. Summary of the Invention

[0005] To address the shortcomings of existing separate assembly manufacturing technologies for impact rotors, this invention provides a novel method for manufacturing impact rotors using electroslag casting and welding. This method offers advantages such as improved material purity, reduced processing volume, shortened manufacturing cycle, and enhanced overall performance of the impact rotor. In particular, it reduces equipment complexity and improves service safety and stability.

[0006] The technical solution of this invention is as follows:

[0007] A method for manufacturing an impact rotor by electroslag casting and welding, characterized by: disassembling the impact rotor circumferentially into spoke units and scoop units; pre-reserving wedge-shaped casting and welding grooves on the circumference of the spoke units; and pre-reserving trapezoidal connecting plates (the dimensions of the wedge-shaped casting and welding grooves and the trapezoidal connecting plates are matched) on the scoop root direction of the scoop units; fabricating a combined crystallizer and consumable electrode according to the structural characteristics and external dimensions of the disassembled spoke units and scoop units; firstly, performing segmented electroslag casting and welding of the spoke units, and then adjusting the spoke units to rotate vertically in a circular manner; clamping the scoop unit combined crystallizer and consumable electrode on the casting and welding groove, and performing casting and welding of the first scoop unit; after the casting and welding of the first scoop unit is completed, rotating the spokes to perform casting and welding of the second scoop unit, and so on until all scoop units are completed, with the number of casting and welding operations N being the same as the number of scoop units; and completing the overall manufacturing of the impact rotor through the casting and welding of the spoke units and scoop units.

[0008] The principle of electroslag casting and welding is as follows: the overall component is divided into modules, the first module is cast using a combined water-cooled crystallizer, and then the crystallizer is moved so that a cavity for the second module is reserved between the crystallizer and the first module. The second module is prepared by electroslag casting directly on the first module, and the second module is simultaneously welded to the first module. This process is repeated to complete the forming and manufacturing of the entire component.

[0009] As a preferred technical solution:

[0010] The combined crystallizer includes two side crystallizers, a bottom arc-starting crystallizer, a movable baffle crystallizer, and a riser crystallizer. The riser crystallizer has a split structure, with the top of the riser crystallizer being horizontal and the bottom being an arc shape that follows the outer circle of the billet.

[0011] The steps for segmented electroslag casting and welding of the spoke unit are as follows: The segmentation method is designed according to the size of the spoke unit and the electroslag furnace's melting and casting capacity; the basic module is cast using electroslag casting; then, the single-sided crystallizer is removed, and the crystallizers of modules adjacent to the basic module are combined with the basic module. Subsequently, electroslag casting and welding of the basic module and adjacent modules are performed to weld the basic module and adjacent modules together; this process is repeated sequentially to complete the overall forming of the spoke unit. The selection of the basic module, the selection of adjacent modules, and the casting and welding sequence are determined based on the segmentation method and the electroslag equipment. For example, when selecting an overall fan-shaped segmentation method, any module can be selected as the basic module; when selecting a circumferential composite fan-shaped segmentation method, it is recommended to select the central circular module as the basic module (e.g., ...). Figure 4 (As shown).

[0012] The wheel spoke unit can be divided into various ways, including but not limited to overall fan-shaped division, overall rectangular division, or circumferential composite fan-shaped division.

[0013] After the spoke unit is fabricated, it is clamped onto a specialized device. This device consists of a support platform, a clamping mechanism, a rotating mechanism, a conductive mechanism, and a cooling mechanism.

[0014] The clamping mechanism includes a hydraulic press and a laser positioning device;

[0015] The rotating mechanism includes a servo motor, a reducer, a spindle, and a support frame;

[0016] The conductive mechanism includes a spherical end, a sliding copper busbar, and a connecting latch;

[0017] The cooling system includes water inlet, water outlet, flow rate monitoring, and temperature monitoring.

[0018] The casting and welding process of the spoon unit is as follows: using a special device, the spoke unit is vertically rotatable 360°. The spoon unit combination crystallizer is positioned above the reserved wedge-shaped casting and welding groove. After the consumable electrode is fixed, the trapezoidal connecting plate is cast and welded. Then, the spoon part is cast and welded until the top of the riser crystallizer is horizontal. After cooling, the spoon unit combination crystallizer is removed. The spoke unit is rotated so that the opening direction of the next casting and welding cavity is vertically upward. The combination crystallizer is reassembled on the next casting and welding cavity. The above process is repeated to cast and weld the next spoon unit until the preparation of all spoon units is completed.

[0019] The electroslag casting and welding manufacturing method for the impact turbine of the present invention comprises the following specific steps:

[0020] 1) Impact wheel disassembly: The impact wheel is disassembled into spoke units and spoon units along the circumference. Wedge-shaped casting and welding grooves are reserved on the circumference of the spoke unit at the designed spoon position, and trapezoidal connecting plates are reserved in the direction of the spoon root of the spoon unit.

[0021] 2) Process design: Based on the size of the spoke unit and the spoon unit, and the electroslag furnace melting and casting capacity, design the block division method, the number of casting connections N, and the electrode size;

[0022] 3) Preparation of combined crystallizer: The combined crystallizer is designed according to the outer contour dimensions of the spoke unit and the spoon unit, including two-sided crystallizer, bottom arc-starting crystallizer, movable baffle crystallizer and riser crystallizer. The riser crystallizer has a split structure, with the top of the riser crystallizer being horizontal and the bottom being arc-shaped following the outer circle of the billet; the structure and dimensions of the riser crystallizer are designed according to the number of castings N and the electrode dimensions designed in step 2).

[0023] 4) Spoke Unit Segmentation Electroslag Casting and Welding: The segmentation method is designed according to the size of the spoke unit and the electroslag furnace melting and casting capacity; the basic module is melted and cast using electroslag casting, then the single-sided crystallizer is removed, and the crystallizers of the modules adjacent to the basic module are combined with the basic module. Subsequently, the basic module and the adjacent modules are electroslag cast and welded together; the above removal and combination operations are repeated to complete the overall forming of the spoke unit; the selection of the basic module and the adjacent modules, as well as the casting and welding sequence, are determined according to the segmentation method and the electroslag equipment.

[0024] 5) Preparation of special device: Combine the clamping mechanism, rotating mechanism, conductive mechanism and cooling mechanism into a special device;

[0025] 6) Spoon unit casting and welding: Using a special device, the spoke unit is vertically rotatable 360°. The spoon unit combination crystallizer is positioned above the reserved wedge-shaped casting and welding groove. After the consumable electrode is fixed, the trapezoidal connecting plate is cast and welded. Then, the spoon part is cast and welded until the top of the riser crystallizer is horizontal. After cooling, the spoon unit combination crystallizer is removed. The spoke unit is rotated so that the opening direction of the next casting and welding cavity is vertically upward. The combination crystallizer is reassembled on the next casting and welding cavity. The above process is repeated to cast and weld the next spoon unit until the preparation of all spoon units is completed.

[0026] 7) Overall manufacturing of the impact wheel: The overall forming of the impact wheel is completed by casting and welding the spoon unit N times on the basis of the spoke unit, and rotating the spoke unit N-1 times. The value of N is the same as the number of spoon units.

[0027] The impact impeller manufactured using the method described in this invention can be used in 200-900MW hydropower units. Its impeller size is 4.0-8.5m, and its maximum weight can reach 120t. The widest part of the cross-section of the scoop unit is 1.2-3.0m.

[0028] Compared with the prior art, the advantages of this invention are as follows:

[0029] (1) The impact wheel is prepared by electroslag casting and welding. Based on the concept of additive manufacturing, it can give full play to the advantages of electroslag metallurgy. It can effectively solve the composition segregation caused by the excessive size of the molten metal pool. The structure is dense, with less segregation and low inclusion content. It can reduce the production difficulty of large impact wheels and the requirements for equipment scale, and the manufacturing difficulty is significantly reduced. Near net forming can reduce the post-processing allowance, improve the metal utilization rate, and greatly reduce the manufacturing cost and manufacturing period.

[0030] (2) The batch forming casting and welding manufacturing mode can effectively reduce the equipment limitations required for the manufacturing of large components, which has strong practicality and promotion value and is easy to realize engineering application.

[0031] (3) The electroslag casting and welding special equipment is adopted, which can simultaneously meet the requirements of the integral forming of the spoke unit and the spoon unit, the stability and rotation of the spoke unit, and the conductivity and cooling of the spoon unit during the manufacturing process. The equipment is a combined structure that is easy to maintain and repair, and the operation process is stable and reliable.

[0032] (4) Impact wheels manufactured by electroslag casting and welding can meet the mechanical properties and flaw detection requirements of forgings of the same material. They have uniform chemical composition, dense structure, refined dendrites, small microsegregation, no porosity, shrinkage cavities and other defects, and inclusions are dispersed. Their fatigue life is better than that of ladle-refined steel. They also have the advantage of isotropy that forgings do not have. At the same time, they have high fatigue resistance and high resistance to crack formation and propagation.

[0033] (5) Metal molded crystallizers replace a large number of non-metallic molding materials such as sand molds, binders and coatings, which reduces solid waste emissions, reduces environmental pollution, and achieves green manufacturing. Attached Figure Description

[0034] Figure 1 Schematic diagram of the impact wheel structure.

[0035] Figure 2 Schematic diagram of the spoke unit structure.

[0036] Figure 3 Schematic diagram of the spoon-shaped unit structure.

[0037] Figure 4 Schematic diagram of the electroslag casting and welding manufacturing module of the spoke unit: (a) overall fan-shaped block, (b) overall rectangular block, (c) circumferential composite fan-shaped block.

[0038] Figure 5 A schematic diagram of the manufacturing principle of electroslag casting and welding: (a) electroslag casting of the basic module, (b) casting and welding the basic module together with the adjacent module.

[0039] Figure 6 Schematic diagram of the casting and welding manufacturing process of the water tank unit.

[0040] Figure 7 Schematic diagram of the special device.

[0041] Figure 8 Side view of the special device.

[0042] Reference numerals: 1. Casting and welding tank, 2. Connecting plate, 3. Consumable electrode, 4. Molten slag pool, 5. Crystallizer, 6. Molten metal pool, 7. Remelted ingot, 8. Bottom water tank, 9. Melting zone, 10. Remelted ingot, 11. Hydraulic station, 12. Conductive mechanism, 13. Clamping mechanism, 14. Rotating mechanism, 15. Support platform, 16. Cooling mechanism, 17. Main shaft, 18. Spoke unit. Detailed Implementation

[0043] Example 1:

[0044] The impact roller is manufactured using electroslag casting and welding. The overall roller structure is as follows: Figure 1 As shown, the maximum external dimension of the rotor is 9500mm.

[0045] (1) Unit splitting: The rotating wheel is split into spoke units and spoon units along the circumference, and the unit structure is as follows: Figure 2 , 3 As shown, the spoke unit has a diameter of 8000mm, and the spoon unit has a height of 600mm (spoon width).

[0046] (3) Process design: Based on the dimensions of the spoke unit and the spoon unit, it is determined that an 800KVA electroslag furnace will be used for casting and welding, and the number of casting and welding times N = 27.

[0047] (4) Selection of crystallizer: a split-type crystallizer made of copper and steel welding, and the crystallizer can be disassembled. The inner cavity of the crystallizer is made of copper plate. The water gap width between the inner cavity plate and the stiffening plate of the copper and steel welded crystallizer is 33mm. The copper plate of the inner cavity of the crystallizer is prepared by metal hot bending + machining manufacturing process.

[0048] (5) Preparation of consumable electrode: Based on the inner cavity size of the crystallizer, a conformal consumable electrode is prepared. The filling ratio is selected as 0.35. The prepared consumable electrode is a sand-cast conformal electrode.

[0049] (6) Preparation of special equipment: Fix the support platform, assemble the servo motor, reducer and spindle to complete the rotation mechanism; fix the clamping plate, connect the hydraulic press and laser positioning equipment to complete the clamping mechanism; assemble and connect the ball end, sliding copper busbar and connecting lock to complete the conductive mechanism; connect the inlet and outlet water channels, adjust the flow rate monitoring and temperature monitoring to complete the cooling mechanism.

[0050] (7) Electroslag casting welding of spoke units: slag system and slag ratio: CaF2: 65%, Al2O3: 25%, MgO: 3%, CaO: 7%, slag layer thickness is 45% of the equivalent diameter of the crystallizer; based on the casting dimensions, the geometric parameters of the electrodes and the crystallizer, and the casting welding process, the casting welding voltage of the spoke units is determined to be 120V and the current to be 15000A. During the casting process, the power of the casting is increased to 160V and the current to 26000A; Figure 4 As shown in (b), the spoke unit is divided into blocks using an overall rectangular block method. The middle complete rectangle is selected as the basic module, and adjacent modules are sequentially cast and welded together to complete the overall forming of the spoke unit.

[0051] (8) Spoon-shaped unit casting and welding: Slag system and slag quantity ratio, CaF2-Al2O3-CaO-MgO-SiO2: 20%, 35%, 30%, 7%, 9%; furnace mouth voltage maintained at 65V, current gradually increased from 5000A at the arc starting end to the maximum cross section of the water bucket perpendicular to the casting direction, at which time the current value is 40000A, and the current growth rate is controlled by the current fluctuation value (±3000) during the casting process. During the feeding period, the normal current is first uniformly reduced to the minimum feeding current within 30 minutes and maintained for 15 minutes; then the minimum feeding current is uniformly increased to 75% of the normal casting current within 5 minutes, repeated 6 times, and the highest casting current each time is 75% of the previous highest casting current, and finally reduced to zero.

[0052] (9) After the casting and welding are completed, the mold is cooled naturally by water for 5 hours. Then, the baffle mold and riser mold are removed. The first scoop unit is rotated 13° clockwise and fastened with a special device. The movable baffle mold and riser mold are then reinstalled to form the casting and welding cavity of the second scoop unit.

[0053] (10) Repeat step (7) to perform casting welding, and then repeat step (8) to rotate and cast welding in sequence. The casting welding of all spoon units is completed, and the overall electroslag casting welding manufacturing of the impact wheel is completed.

[0054] The mechanical properties of the prepared impact sprocket meet the requirements of ASTM A473-19 "Standard Specification for Stainless Steel Forgings", with a yield strength of 620 MPa, tensile strength of 795 MPa, elongation of 15%, reduction of area of ​​45%, impact toughness of 120 J, and hardness (Britt) of 265; the radial strength deviation of the sprocket body is less than 30 MPa; the ultrasonic testing (UT) of the casting according to CCH 70-4 meets the standard of level 1-2.

[0055] Example 2:

[0056] The impact roller is manufactured using electroslag casting and welding. The overall roller structure is as follows: Figure 1 As shown, the maximum external dimension of the rotor is 9500mm.

[0057] (1) Unit splitting: The rotating wheel is split into spoke units and spoon units along the circumference, and the unit structure is as follows: Figure 1 As shown, the spoke unit has a diameter of 8000mm and the spoon unit has a height of 600mm (spoon width).

[0058] (3) Process design: Based on the dimensions of the spoke unit and the spoon unit, an 800KVA electroslag furnace was selected for casting and welding, with N=14 casting and welding cycles (13 spoon units include 2 water buckets, and the 14th spoon unit is 1 water bucket).

[0059] (4) Selection of crystallizer: a split-type crystallizer made of copper and steel welding, and the crystallizer can be disassembled. The inner cavity of the crystallizer is made of copper plate. The water gap width between the inner cavity plate and the stiffening plate of the copper and steel welded crystallizer is 33mm. The copper plate of the inner cavity of the crystallizer is prepared by metal hot bending + machining manufacturing process.

[0060] (5) Preparation of consumable electrode: Based on the inner cavity size of the crystallizer, a conformal consumable electrode is prepared. The filling ratio is selected as 0.45. The prepared consumable electrode is a sand-cast conformal electrode.

[0061] (6) Preparation of special equipment: Fix the support platform, assemble the servo motor, reducer and spindle to complete the rotation mechanism; fix the clamping plate, connect the hydraulic press and laser positioning equipment to complete the clamping mechanism; assemble and connect the ball end, sliding copper busbar and connecting lock to complete the conductive mechanism; connect the inlet and outlet water channels, adjust the flow rate monitoring and temperature monitoring to complete the cooling mechanism.

[0062] (7) Electroslag casting welding of spoke units: slag system and slag ratio: CaF2: 65%, Al2O3: 25%, MgO: 3%, CaO: 7%, slag layer thickness is 45% of the equivalent diameter of the crystallizer; based on the casting dimensions, the geometric parameters of the electrodes and the crystallizer, and the casting welding process, the casting welding voltage of the spoke units is determined to be 120V and the current to be 15000A. During the casting process, the power of the casting is increased to 160V and the current to 26000A; Figure 4 As shown in (c), the spoke unit is divided into blocks using a circumferential composite sector block method. The middle circular module is selected as the basic module, and adjacent modules are sequentially cast and welded together to complete the overall forming of the spoke unit.

[0063] (8) Spoon-shaped unit casting and welding: Slag system and slag quantity ratio, CaF2-Al2O3-CaO-MgO-SiO2: 20%, 35%, 30%, 7%, 9%; furnace mouth voltage maintained at 85V, current gradually increased from 7000A at the arc starting end to the maximum cross-section of the water bucket perpendicular to the casting direction, at which time the current value is 50000A, and the current growth rate is controlled by the current fluctuation value (±4000) during the casting process. During the feeding period, the normal current is first uniformly reduced to the minimum feeding current within 30 minutes and maintained for 15 minutes; then the minimum feeding current is uniformly increased to 75% of the normal casting current within 5 minutes, repeated 6 times, and the highest casting current each time is 75% of the previous highest casting current, and finally reduced to zero.

[0064] (9) After the casting and welding are completed, the mold is cooled naturally by water for 5 hours. Then, the baffle mold and riser mold are removed. The first scoop unit is rotated 25° clockwise and fastened with a special device. The movable baffle mold and riser mold are then reinstalled to form the casting and welding cavity of the second scoop unit.

[0065] (10) Repeat step (7) to perform casting welding, and then repeat step (8) to rotate and cast welding in sequence. The casting welding of all spoon units is completed, and the overall electroslag casting welding manufacturing of the impact wheel is completed. The mechanical properties of the prepared impact wheel meet the requirements of ASTM A473-19 "Standard Specification for Stainless Steel Forgings". The casting is subjected to ultrasonic testing (UT) according to CCH70-4 to reach the level 1-2 standard.

[0066] Matters not covered in this invention are common knowledge.

[0067] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to 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 in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for manufacturing an impact turbine by electroslag casting and welding, characterized in that: The impact wheel is disassembled circumferentially into spoke units and spoon units. Wedge-shaped welding grooves are pre-reserved on the circumference of the spoke units, and trapezoidal connecting plates are pre-reserved at the root of the spoon units. Based on the structural characteristics and dimensions of the disassembled spoke and spoon units, a combined crystallizer and consumable electrode are fabricated. First, the spoke units are electroslag welded in sections, then the spoke units are adjusted to rotate vertically in a circular motion. The spoon unit combined crystallizer and consumable electrode are clamped in the welding groove, and the first spoon unit is welded. After the first spoon unit is welded, the spokes are rotated to weld the second spoon unit, and so on until all spoon units are welded. The number of times N is welded is the same as the number of spoon units. The overall manufacturing of the impact wheel is completed through the welding of the spoke and spoon units. The specific steps are as follows: 1) Impact wheel disassembly: The impact wheel is disassembled into spoke units and spoon units along the circumference. Wedge-shaped casting and welding grooves are reserved on the circumference of the spoke unit at the designed spoon position, and trapezoidal connecting plates are reserved in the direction of the spoon root of the spoon unit. 2) Process design: Based on the size of the spoke unit and the spoon unit, and the electroslag furnace melting and casting capacity, design the block division method, the number of casting connections N, and the electrode size; 3) Preparation of combined crystallizer: The combined crystallizer is designed according to the outer contour dimensions of the spoke unit and the spoon unit, including the two-sided crystallizer, the bottom arc-starting crystallizer, the movable baffle crystallizer and the riser crystallizer. The riser crystallizer has a split structure, with the top of the riser crystallizer being horizontal and the bottom being arc-shaped following the outer circle of the billet. The structure and dimensions of the riser crystallizer are designed based on the number of casting cycles N and electrode dimensions designed in step 2). 4) Spoke Unit Segmentation Electroslag Casting and Welding: The segmentation method is designed according to the size of the spoke unit and the electroslag furnace melting and casting capacity; the basic module is melted and cast using electroslag casting, then the single-sided crystallizer is removed, and the crystallizers of the modules adjacent to the basic module are combined with the basic module. Subsequently, the basic module and the adjacent modules are electroslag cast and welded together; the above removal and combination operations are repeated to complete the overall forming of the spoke unit; the selection of the basic module and the adjacent modules, as well as the casting and welding sequence, are determined according to the segmentation method and the electroslag equipment. 5) Preparation of special device: Combine the clamping mechanism, rotating mechanism, conductive mechanism and cooling mechanism into a special device; 6) Spoon unit casting and welding: Using a special device, the spoke unit is vertically rotatable 360°. The spoon unit combination crystallizer is positioned above the reserved wedge-shaped casting and welding groove. After the consumable electrode is fixed, the trapezoidal connecting plate is cast and welded. Then, the spoon part is cast and welded until the top of the riser crystallizer is horizontal. After cooling, the spoon unit combination crystallizer is removed. The spoke unit is rotated so that the opening direction of the next casting and welding cavity is vertically upward. The combination crystallizer is reassembled on the next casting and welding cavity. The above process is repeated to cast and weld the next spoon unit until the preparation of all spoon units is completed. 7) Overall manufacturing of the impact wheel: The overall forming of the impact wheel is completed by casting and welding the spoon unit N times on the basis of the spoke unit, and rotating the spoke unit N-1 times. The value of N is the same as the number of spoon units.

2. The method for manufacturing an impact turbine by electroslag casting and welding according to claim 1, characterized in that: The combined crystallizer includes two side crystallizers, a bottom arc-starting crystallizer, a movable baffle crystallizer, and a riser crystallizer. The riser crystallizer has a split structure, with the top of the riser crystallizer being horizontal and the bottom being an arc shape that follows the outer circle of the billet.

3. The method for manufacturing an impact turbine by electroslag casting and welding according to claim 1, characterized in that, The steps for segmented electroslag casting and welding of the spoke unit are as follows: The segmentation method is designed according to the size of the spoke unit and the electroslag furnace casting capacity; the basic module is cast using electroslag casting; then, the single-sided crystallizer is removed, and the crystallizers of modules adjacent to the basic module are combined with the basic module. Subsequently, electroslag casting and welding of the basic module and adjacent modules are performed to weld the basic module and adjacent modules together; the above removal and combination operations are repeated sequentially to complete the overall forming of the spoke unit; the selection of the basic module and adjacent modules, as well as the casting and welding sequence, are determined according to the segmentation method and the electroslag equipment.

4. The method for manufacturing an impact turbine by electroslag casting and welding according to claim 3, characterized in that: The spoke unit can be divided into overall fan-shaped blocks, overall rectangular blocks, or circumferential composite fan-shaped blocks.

5. The method for manufacturing an impact turbine by electroslag casting and welding according to claim 1, characterized in that: After the spoke unit is fabricated, it is clamped onto a specialized device. This device consists of a support platform, a clamping mechanism, a rotating mechanism, a conductive mechanism, and a cooling mechanism. The clamping mechanism includes a hydraulic press and a laser positioning device; The rotating mechanism includes a servo motor, a reducer, a spindle, and a support frame; The conductive mechanism includes a spherical end, a sliding copper busbar, and a connecting latch; The cooling system includes water inlet, water outlet, flow rate monitoring, and temperature monitoring.

6. The method for manufacturing an impact turbine by electroslag casting and welding according to claim 1, characterized in that, The casting and welding process of the spoon unit is as follows: using a special device, the spoke unit is vertically rotatable 360°. The spoon unit combination crystallizer is positioned above the reserved wedge-shaped casting and welding groove. After the consumable electrode is fixed, the trapezoidal connecting plate is cast and welded. Then, the spoon part is cast and welded until the top of the riser crystallizer is horizontal. After cooling, the spoon unit combination crystallizer is removed. The spoke unit is rotated so that the opening direction of the next casting and welding cavity is vertically upward. The combination crystallizer is reassembled on the next casting and welding cavity. The above process is repeated to cast and weld the next spoon unit until the preparation of all spoon units is completed.

7. An impact wheel manufactured according to the method of claim 1, characterized in that: The impact wheel has a size of 4.0-8.5m and a maximum weight of 120t, with the widest part of the spoon unit cross-section being 1.2-3.0m.

8. The impact wheel according to claim 7, characterized in that: The impact turbine is used in 200-900MW hydropower units.

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