A precision forming method for the guide pipe of a gas turbine stator blade

Abstract

The present invention relates to the technical field of metal sheet processing and plastic forming, and in particular to a precision forming method for a guide pipe of a gas turbine stationary blade, which mainly consists of five parts, namely a stock preparation step, a cold stamping step, a flanging step, a thermal relaxation step and a seam welding step; the precision forming method for the guide pipe of the gas turbine stationary blade of the present invention uses a stamping die, a flanging die and a thermal relaxation die, and can manufacture a guide pipe part with a complex shape and a precision reaching the wire level; in addition, in the die design, there is no need to consider the die surface compensation problem caused by springback during part forming, reducing the design and manufacturing costs.

Description

Technical Field

[0001] The present invention relates to the technical field of metal sheet processing and plastic forming, and in particular to a precision forming method for a guide pipe of a gas turbine stationary blade. Background Art

[0002] A gas turbine is an advanced and complex power machinery equipment, and is one of the important symbols to measure a country's scientific and technological strength and comprehensive national strength. The blade is the core component in the gas turbine to achieve the "work - function" conversion, and its safety and reliability are crucial for the normal operation of the gas turbine. Since the blade is in a high - temperature and high - pressure working environment, it is necessary to reduce the internal temperature field of the blade through a suitable method to improve its service life.

[0003] The gas turbine turbine stationary blade has a hollow structure, and a guide pipe (also called a blade bushing) is provided in the inner cavity, as Figure 1 shown. Cooling air is introduced into the guide pipe, and a large number of small holes on the guide pipe wall guide the cold air to impact the inner wall surface of the blade, thereby reducing the blade temperature. To ensure excellent cooling effect during the cold air impact process, an accurate distance must be maintained between the guide pipe and the inner wall surface of the blade. Since the blade itself has a high - precision complex inner cavity, it is required that the guide pipe also has a high - precision complex profile, which is difficult to manufacture.

[0004] In order to adapt to the complex inner cavity structure of the blade, the guide pipe is a tubular structure with a non - regular torsional curved surface profile and is non - uniform in cross - section along the pipe length, as Figure 1 and Figure 2 shown; therefore, it cannot be manufactured by a single stamping method and must be completed by composite forming methods such as stamping - flanging - welding. Designing reasonable processes and tooling becomes the key.

[0005] In addition, since the blade and the guide pipe are in a high - temperature and high - pressure working environment for a long time, high - strength high - temperature alloys are usually selected as the materials. Due to the high strength of this type of material, the springback amount during the forming process is relatively large (so - called springback refers to the elastic deformation that occurs after the metal material is unloaded during forming). If the corresponding die is made according to the design dimensions of the guide pipe, the formed product will inevitably have springback, seriously reducing the dimensional accuracy of the part. In actual production, the die profile is often corrected by multiple trial - and - error and die repair methods. Even so, the product accuracy is still difficult to meet the design requirements.

[0006] Publication No. 105665577A designed a forming device for a cold air duct. Although this device can improve the local wrinkling problem of the guide pipe forming, it cannot improve the forming accuracy of the part; Publication No. 102310135A designed a process equipment for the internal high - pressure forming of the guide pipe. Although the turbine blade guide pipe can be obtained by using this equipment, the product will be thinned, prone to cracking, and both the process and the equipment are relatively complex. Summary of the Invention

[0007] To solve the above problems, the object of the present invention is to provide a precision forming method for the guide pipe of a gas turbine static blade, that is, to provide a room-temperature stamping-thermal relaxation composite forming method for the inner cavity guide pipe of a gas turbine static blade. By using a stamping die, a flanging die and a thermal relaxation die, a guide pipe part with complex shape and precision reaching the wire level can be manufactured; in addition, in the die design, there is no need to consider the die surface compensation problem caused by springback during part forming, which reduces the design and manufacturing costs.

[0008] The object of the present invention can be achieved by the following technical solutions:

[0009] The present invention provides a precision forming method for the guide pipe of a gas turbine static blade, comprising the following steps:

[0010] (S1) Room-temperature stamping: Place the pretreated trapezoidal blank in a stamping die for room-temperature stamping, bend and form part of the back of the blade and the leading-edge fillet, and stretch and form the rest into a straight surface to obtain a room-temperature stamped blank.

[0011] (S2) Flanging: Place the room-temperature stamped blank obtained in step (S1) in a flanging die for flanging treatment, form the blade basin surface and the back of the blade, and perform flanging on the middle partition and the blade basin surface and the back of the blade to obtain a guide pipe precursor.

[0012] (S3) Thermal relaxation: Place the guide pipe precursor obtained in step (S2) in a thermal relaxation die and perform thermal relaxation treatment under a vacuum state, and then post-process to obtain a guide pipe part (already formed, with only a gap left on the middle partition surface).

[0013] (S4) Seam welding: Weld the gap of the guide pipe part obtained in step (S3) to complete the seam welding of the guide pipe part, and obtain a gas turbine static blade guide pipe with a precision above the wire level.

[0014] In an embodiment of the present invention, in step (S1), the pretreated trapezoidal blank required for forming the guide pipe is obtained by cutting the sheet material.

[0015] In an embodiment of the present invention, the cutting is selected from one of wire cutting or laser cutting;

[0016] During cutting, based on the three-dimensional digital model of the guide pipe part, and using modeling design software to unfold the three-dimensional digital model along the weld position to obtain the blank unfolding size, and regularize and optimize the sheet material to obtain the shape and size of the sheet material for manufacturing the guide pipe.

[0017] In an embodiment of the present invention, in step (S1), during the normal-temperature stamping process, the pre-treated trapezoidal blank is placed above the female die of the stamping die, and the male die of the stamping die bends and forms part of the back of the blade and the fillet of the leading edge under the drive of the servo press, and the rest is stamped and stretched into a straight surface.

[0018] In an embodiment of the present invention, in step (S2), during the flanging process, the left and right half dies and the flanging core of the flanging die are used to form the blade basin surface and the back of the blade, and the pressing plate and the triangular block of the flanging die are used to perform flanging treatment on the fillets of the middle partition plate, the blade basin surface and the back of the blade.

[0019] In an embodiment of the present invention, in step (S3), after the precursor of the draft tube is placed in the thermal relaxation die, a locking force is applied by bolts, and the entire thermal relaxation die with the precursor of the draft tube fixed is placed in a vacuum heat treatment furnace for vacuum high-temperature relaxation treatment.

[0020] In an embodiment of the present invention, in step (S3), during the thermal relaxation process, the temperature is 900 - 1000 °C and the time is 1.5 - 2.5 h.

[0021] In an embodiment of the present invention, during the thermal relaxation process, the temperature is 950 °C and the time is 2 h.

[0022] In an embodiment of the present invention, in step (S3), during the thermal relaxation process, the heating rate is 10 °C / min.

[0023] In an embodiment of the present invention, in step (S3), the post-treatment is demolding after cooling.

[0024] In an embodiment of the present invention, after the thermal relaxation process ends, the draft tube part is cooled to room temperature with the furnace, or cooled with the furnace until the temperature drops below 100 °C, and after taking out the entire thermal relaxation die, it continues to cool at room temperature.

[0025] In an embodiment of the present invention, in step (S4), during the seam welding process, the draft tube part is fixed by an aluminum alloy welding fixture, and the seam is welded by laser.

[0026] The present invention provides a precision forming method for the draft tube of a gas turbine stator blade. The initial shape of the part is made by a stamping-flanging combined process; on this basis, the thermal relaxation method is used to remove residual stress; the present invention solves the problem that it is difficult to meet the part accuracy due to sheet metal springback, and greatly improves the manufacturing accuracy of the draft tube.

[0027] The working principle of the present invention is as follows:

[0028] At high temperatures, metals will undergo stress relaxation. Stress relaxation refers to the phenomenon where, when the deformation of a material remains constant at a constant temperature, the stress in the material decreases over time. Based on the principle of high-temperature stress relaxation, the stamping-thermal relaxation composite forming method for the guide pipe designed in this invention mainly includes the following steps:

[0029] (1) Cold stamping: The punch bends the blank under the action of a servo press until the punch fits with the die, forming some characteristic shapes and the leading-edge fillet, preparing for the next flanging step.

[0030] (2) Flanging: Transfer the stamped guide pipe to a flanging half-die to form the main features such as the blade pressure surface and the blade suction surface, and perform flanging on the fillets between the intermediate partition and the blade pressure surface and the blade suction surface.

[0031] (3) Thermal relaxation: Put the entire tooling containing the part and the thermal relaxation die into a vacuum heat treatment furnace, keep it at a certain temperature for a period of time to allow the part to undergo stress relaxation, and the part will not deform under the constraint of the die.

[0032] (4) Unloading: After the thermal relaxation is completed and the die cools down to room temperature, remove the constraint of the thermal relaxation die. At this time, the elastic strain inside the part is transformed into permanent creep strain, obtaining a high-precision guide pipe part.

[0033] Compared with the prior art, this invention has the following beneficial effects:

[0034] (1) The forming method provided by this invention can eliminate the residual stress after stamping, solve the problem that it is difficult to meet the part precision requirements due to springback, and manufacture a thin-walled complex structure guide pipe part with precision meeting the design requirements.

[0035] (2) The guide pipe parts manufactured by the forming method provided by this invention are detected by a three-dimensional laser scanner, and have a very high repeatability precision and the manufacturing precision is above the wire level.

[0036] (3) The forming method provided by this invention can eliminate the residual stress. Therefore, in terms of die design, the die surface size is the same as the part surface design size, without considering the springback of the part after forming and the die surface compensation problem, reducing the burden of trial die and die repair in actual production and lowering the design cost.

[0037] (4) The forming method provided by this invention does not require special equipment and production tools such as those needed for internal high-pressure forming, and the process conditions are simple and easy to meet, and the operating conditions are mild and easy to master.

[0038] (5) The forming method provided by this invention has no specific requirements for the shape and size of the part, is not limited to the guide pipe of the static blade of a gas turbine, and can also be extended to the precision forming of other complex structure parts such as those used in other aeroengines or gas turbines. Description of the Drawings

[0039] Figure 1 It is a schematic structural diagram of a typical gas turbine stator blade guide pipe;

[0040] Figure 2 It is an accurate unfolding schematic diagram of the trapezoidal blank of the gas turbine stator blade guide pipe of the present invention;

[0041] Figure 3 It is a schematic diagram of the regularization and optimization of the trapezoidal blank of the gas turbine stator blade guide pipe of the present invention;

[0042] Figure 4 It is a schematic diagram of the stamping die of the present invention;

[0043] Figure 5 It is a schematic diagram of the flanging die of the present invention;

[0044] Figure 6 It is a schematic diagram of the thermal relaxation die of the present invention;

[0045] Figure 7 It is a schematic diagram of the aluminum alloy welding fixture of the present invention;

[0046] Reference numerals in the figures:

[0047] 1. Upper template; 2. Punch; 3. Stopper pin; 4. Die; 5. Lower template; 6. Guide pillar; 7. Small guide pillar; 8. Guide sleeve; 9. Lifting hole; 10. Pressure plate; 11. Flanging core; 12. Flanging half die; 13. Φ16 pin hole; 14. M16 threaded hole; 15. Triangular block; 16. Φ20 through hole; 17. Thermal relaxation half die; 18. M20 threaded hole; 19. Φ20 pin hole; 20. Thermal relaxation core; 21. Top opening of the fixture; 22. Aluminum alloy core; 23. Welding fixture. Detailed Embodiment

[0048] The present invention provides a precision forming method for a gas turbine stator blade guide pipe, including the following steps:

[0049] (S1) Cold stamping: Place the pretreated trapezoidal blank in the stamping die for cold stamping, bend and form part of the back of the blade and the leading edge fillet, and stretch and form the remaining part into a straight surface to obtain a cold stamping blank;

[0050] (S2) Flanging: Place the cold stamping blank obtained in step (S1) in the flanging die for flanging treatment, form the blade basin surface and the back of the blade, and perform flanging on the intermediate partition and the blade basin surface and the back of the blade to obtain a guide pipe precursor;

[0051] (S3) Thermal relaxation: Place the precursor of the guide pipe obtained in step (S2) in a thermal relaxation mold and perform thermal relaxation treatment under vacuum, followed by post-treatment to obtain a guide pipe part (already formed, with only a gap left on the middle partition surface);

[0052] (S4) Seam welding: Weld the gap of the guide pipe part obtained in step (S3) to complete the seam welding of the guide pipe part, and obtain a gas turbine stationary blade guide pipe with a precision above the wire level.

[0053] In an embodiment of the present invention, in step (S1), a preprocessed trapezoidal blank required for forming the guide pipe is obtained by cutting the sheet.

[0054] In an embodiment of the present invention, the cutting is selected from one of wire cutting or laser cutting;

[0055] During cutting, based on the three-dimensional digital model of the guide pipe part and using modeling design software to unfold the three-dimensional digital model along the weld position to obtain the blank unfolding size, the sheet is regularized and optimized to obtain the shape and size of the sheet for manufacturing the guide pipe.

[0056] In an embodiment of the present invention, in step (S1), during normal temperature stamping, place the preprocessed trapezoidal blank above the female die of the stamping mold, and the male die of the stamping mold bends to form part of the back of the blade and the leading edge fillet under the drive of the servo press, and the rest is stamped and stretched into a straight surface.

[0057] In an embodiment of the present invention, in step (S2), during flanging, use the left and right half molds and the flanging core of the flanging mold to form the blade basin surface and the back of the blade, and use the pressing plate and triangular block of the flanging mold to perform flanging treatment on the fillets between the middle partition and the blade basin surface and the back of the blade.

[0058] In an embodiment of the present invention, in step (S3), after the precursor of the guide pipe is placed in the thermal relaxation mold, apply a locking force using bolts, and place the entire thermal relaxation mold with the precursor of the guide pipe fixed in a vacuum heat treatment furnace for vacuum high-temperature relaxation treatment.

[0059] In an embodiment of the present invention, in step (S3), during thermal relaxation, the temperature is 900 - 1000 °C and the time is 1.5 - 2.5 h.

[0060] In an embodiment of the present invention, during thermal relaxation, the temperature is 950 °C and the time is 2 h.

[0061] In an embodiment of the present invention, in step (S3), during thermal relaxation, the heating rate is 10 °C / min.

[0062] In an embodiment of the present invention, in step (S3), the post-treatment is demolding after cooling.

[0063] In an embodiment of the present invention, after the thermal relaxation process ends, the guide pipe part is cooled to room temperature in the furnace, or cooled in the furnace until the temperature drops below 100°C, and then the entire thermal relaxation mold is taken out and cooled continuously at room temperature.

[0064] In an embodiment of the present invention, in step (S4), during the seam welding process, the guide pipe part is fixed by an aluminum alloy welding fixture, and the seam is welded by laser.

[0065] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0066] Example 1

[0067] This example provides a stamping-thermal relaxation composite forming method for the guide pipe of a gas turbine static blade, including stock preparation, stamping, flanging, thermal relaxation, and seam welding; specifically as follows:

[0068] (S1) Stock preparation: Based on the three-dimensional digital model of the guide pipe part, considering the flanging deformation and welding allowance, the digital model is unfolded along the weld position by UG to obtain the blank unfolded size, and the flat blank shape and size for manufacturing the guide pipe are obtained by regularizing and optimizing the blank. The trapezoidal blank required for forming the guide pipe is obtained by cutting the sheet by wire cutting or laser cutting; the accurate unfolding schematic diagram and the regularization and optimization schematic diagram of the guide pipe are respectively as Figure 2 and Figure 3 shown;

[0069] (S2) Normal temperature stamping: The trapezoidal blank obtained in step (S1) is placed above the female die 4 of the stamping die as shown in Figure 4 . The placement position of the trapezoidal blank is restricted by the stop pin 3. Otherwise, after further flanging, the weld position will not be centered, which will hinder the subsequent processes; the male die 2 bends the trapezoidal blank under the action of the servo press until the male die 2 fits with the female die 4, forming part of the characteristic shape and the leading edge fillet, and the rest is stretched into a straight surface. The leading edge fillet shape formed by stamping can be used as the positioning feature for the next step;

[0070] Among them, the stamping die includes an upper template 1, a lower template 5, a stop pin 3, a punch 2, a die 4, a guide bushing 8, a guide pillar 6, and a small guide pillar 7. The upper template 1 is arranged parallel and at intervals above the lower template 5. The die 4 is arranged on the upper surface of the lower template 5. A stop pin 3 is arranged on the upper surface of the die 4. The punch 2 is arranged on the lower surface of the upper template 1. A small guide pillar 7 is also arranged on the lower surface of the punch 2. The guide pillar 6 is connected to the guide bushing 8 and is symmetrically arranged on both sides of the punch 2 along the central axis of the punch 2. Lifting holes 9 are also arranged on the upper template 1 and the lower template 5. The functions of the guide bushing 8, the guide pillar 6, and the small guide pillar 7 are to accurately guide the up and down stroke of the stamping die and improve the stability of the stamping process. The punch 2 and the die 4 are made of quenched cold work die steel Cr12MoV. The lifting holes 9 are used for the crane to place the stamping die on the servo press;

[0071] To avoid negative angles in the stamping direction, the upper part of the blade back is bent into a straight surface, ensuring the smooth progress of forming; at the same time, a small guide pillar 7 component is specially set in the stamping die to further improve the accuracy and stability; in addition, the placement position of the blank is restricted by the stop pin 3, otherwise the weld position will not be centered after flanging, which will hinder the subsequent processes; the leading edge fillet shape formed by stamping can be used as the positioning feature for the next step.

[0072] (S3) Flanging: Transfer the stamped guide pipe to the Figure 5 shown flanging die to form the main features such as the blade bowl surface and the blade back surface, and flanging the fillets of the middle partition plate with the blade bowl surface and the blade back surface. Since the outer shape of the guide pipe is a complex twisted surface and cannot be directly placed into the split die, when transferring the guide pipe to the flanging die, first do not use the pressure plate 10, and there is a certain gap between the left and right split dies. Continuously press the part wrapped with the flanging core 11 into the split die, and at the same time continuously tighten the left and right split dies with bolts. This process needs to be carried out step by step until the part is completely close to the split die. After the guide pipe is pressed into the split die and locked, first apply force to the straight surface of the part laterally to form an inclined surface with an inclined trend, and then connect the pressure plate 10 and the split die with bolts. Continuously tighten the bolts to make the pressure plate 10 press down and apply pressure to the inclined surface of the part through the triangular block 15 in the middle to make the inclined surface of the part close, thereby forming the fillets of the middle partition plate with the blade bowl surface and the blade back surface;

[0073] Among them, the flanging die includes a pressing plate 10, a flanging half die 12, a flanging core 11 and a triangular block 15. The pressing plate 10 is arranged on the upper surface of the flanging half die 12. The flanging half die 12 is reserved with a space for accommodating the flanging core 11, and the pressing plate 10 is reserved with a space for accommodating the triangular block 15. The lower surface of the triangular block 15 is in contact with the upper surface of the flanging core 11. The flanging half die 12 is provided with an M16 threaded hole 14 and a Φ16 pin hole 13, and is bolted together as a whole through the M16 threaded hole 14 and positioned through the Φ16 pin hole 13. The pressing plate 10 and the flanging half die 12 are bolted together as a whole through a Φ20 through hole 16. The flanging die is prepared from quenched Cr12MoV to ensure the service strength during the forming process. The flanging core 11 plays a role in supporting the part surface.

[0074] On the one hand, the flanging step needs to preliminarily form the main feature surfaces such as the back surface and the basin surface of the guide pipe. On the other hand, it needs to flanging-form the fillets between the intermediate partition surface, the basin surface and the back surface. Based on the outer surface of the guide pipe, the surface features of the flanging die are constructed. The surface dimensions of the die are consistent with the surface design dimensions of the part. Only considering the plate thickness, there is no need to consider the springback of the part after forming and the die surface compensation problem, which reduces the burden of trial die and die repair in actual production.

[0075] (S4) Thermal relaxation: Place the flanged guide pipe part in the thermal relaxation die as shown in Figure 6 . Use bolts to apply a locking force to the thermal relaxation half die 17 and the part wrapped with the flanging core 11. Put the whole set of thermal relaxation die with the fixed part into a vacuum heat treatment furnace, evacuate the furnace cavity (ensure that the surface of the part is bright and oxidation-free after relaxation). After the vacuum degree is sufficient, heat the high-temperature stainless steel die containing the part to 950 °C at a heating rate of 10 °C / min and hold for 120 min. After the relaxation is over, let the die cool with the furnace water. After the temperature drops below 100 °C, the furnace door can be opened to take out the die. After the die naturally cools to room temperature, disassemble the die to obtain the guide pipe part.

[0076] Among them, the thermal relaxation die consists of a thermal relaxation core 20 and a thermal relaxation half die 17. There is a space for accommodating the thermal relaxation core 20 at the connection position of the two symmetrical thermal relaxation half dies 17. The thermal relaxation half die 17 is provided with an M20 threaded hole 18 and a Φ20 pin hole 19, and is bolted together as a whole through the M20 threaded hole 18 and positioned through the Φ20 pin hole 19.

[0077] Among them, the flanging core 11 in the flanging die and the thermal relaxation core 20 in the thermal relaxation die are the same. The surface of the thermal relaxation half die 17 and the thermal relaxation core 20 are the inner and outer surfaces of the guide pipe part, so the gap between them is the thickness of the sheet. The quality of the thermal relaxation die plays a crucial role in the forming method of this embodiment. Since the thermal relaxation die is used under harsh temperature conditions and has to withstand repeated high-temperature heating, the die material must have good high-temperature resistance and oxidation resistance to meet the service life requirements for long-term use at high temperatures. Preferably, the thermal relaxation die can be made of 310S (0Cr25Ni20) heat-resistant stainless steel. This material has excellent corrosion resistance in an oxidizing medium, and the general service temperature is above 1050°C, and it can operate at high temperatures for a long time, making it an ideal material for manufacturing thermal relaxation dies.

[0078] (S5) Seam welding: Install the formed slotted guide pipe into the aluminum alloy welding fixture 23 as shown in Figure 7 . At this time, the top opening 21 of the fixture exposes the weld seam reserved on the middle partition surface. The laser wire filling welding method is used to melt the wire homologous to the base material and fill it into the weld seam. After full welding, the aluminum alloy core 22 is separated from the part to obtain a guide pipe closure with a manufacturing accuracy of ±0.1 mm or more.

[0079] Among them, the aluminum alloy welding fixture 23 includes a welding fixture 23 and an aluminum alloy core 22. A space for accommodating the thermal relaxation core 20 is provided at the end of the connection position of two symmetric thermal relaxation half dies 17. The aluminum alloy core 22 in the aluminum alloy welding fixture 23 has the same shape as the thermal relaxation core 20, and the material is changed to aluminum alloy.

[0080] To reduce post-welding deformation and improve assembly accuracy, it is necessary to use the aluminum alloy welding fixture 23 to fix the part during the welding process. The fixture material is selected as aluminum alloy because the melting points of aluminum alloy and superalloy differ greatly and they basically will not weld together, which is convenient for separating the part from the fixture. For the slotted guide pipe that has been cleaned before welding, the wire is cut from the base material by wire cutting, and the part and the fixture are assembled together. At this time, the middle partition surface part is exposed outside the fixture. The laser wire filling welding method is used to melt the wire and fill it into the weld seam reserved on the middle partition surface, so as to circumferentially close the part.

[0081] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. Those who are familiar with the technology in this field can obviously make various modifications to these embodiments easily and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the interpretation of the present invention should be within the protection scope of the present invention.

Claims

1. A precision forming method for the guide pipe of a gas turbine stationary blade, characterized in that, it includes the following steps: (S1) Cold stamping: Place the pretreated trapezoidal blank in a stamping die for cold stamping, bend and form part of the back of the blade and the leading edge fillet, and stretch and form the remaining part into a straight surface to obtain a cold-stamped blank; (S2) Flanging: Place the cold-stamped blank obtained in step (S1) in a flanging die for flanging treatment, form the blade basin surface and the back of the blade, and perform flanging on the intermediate partition and the blade basin surface and the back of the blade to obtain a guide pipe precursor; (S3) Thermal relaxation: Place the guide pipe precursor obtained in step (S2) in a thermal relaxation die, and perform thermal relaxation treatment under a vacuum state, and post-treat to obtain a guide pipe part; (S4) Seam welding: Weld the gap of the guide pipe part obtained in step (S3), complete the seam welding of the guide pipe part, and obtain a guide pipe for a gas turbine stationary blade with a precision above the wire level.

2. A precision forming method for the guide pipe of a gas turbine stationary blade according to claim 1, characterized in that, in step (S1), the pretreated trapezoidal blank required for forming the guide pipe is obtained by cutting the sheet material.

3. A precision forming method for the guide pipe of a gas turbine stationary blade according to claim 2, characterized in that, the cutting is selected from one of wire cutting or laser cutting; during cutting, based on the three-dimensional digital model of the guide pipe part, and using modeling design software to unfold the three-dimensional digital model along the weld position to obtain the blank unfolded size, and regularize and optimize the sheet material to obtain the shape and size of the sheet material for manufacturing the guide pipe.

4. A precision forming method for the guide pipe of a gas turbine stationary blade according to claim 3, characterized in that, in step (S1), during cold stamping, place the pretreated trapezoidal blank above the female die of the stamping die, and the male die of the stamping die bends and forms part of the back of the blade and the leading edge fillet under the drive of a servo press, and the remaining part is stretched and formed into a straight surface.

5. A precision forming method for the guide pipe of a gas turbine stationary blade according to claim 1, characterized in that, in step (S2), during flanging, use the left and right half dies and the flanging core of the flanging die to form the blade basin surface and the back of the blade, and use the pressing plate and triangular block of the flanging die to perform flanging on the fillets of the intermediate partition and the blade basin surface and the back of the blade.

6. A precision forming method for the guide pipe of a gas turbine stationary blade according to claim 1, characterized in that, in step (S3), during thermal relaxation, the temperature is 900 - 1000 °C and the time is 1.5 - 2.5 h.

7. A precision forming method for the guide pipe of a gas turbine stationary blade according to claim 6, characterized in that, during thermal relaxation, the temperature is 950 °C and the time is 2 h.

8. A precision forming method for the guide pipe of a gas turbine stationary blade according to claim 1, characterized in that, in step (S3), during thermal relaxation, the heating rate is 10 °C / min.

9. A precision forming method for the guide pipe of a gas turbine stationary blade according to claim 1, characterized in that, in step (S3), the post-treatment is demoulding after cooling.

10. A precision forming method for the guide pipe of a gas turbine stationary blade according to claim 1, characterized in that, in step (S4), during the seam welding process, the welding method is laser welding.

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