Cavity engine border screw precision casting processing technology with electron beam punching

Abstract

The application relates to the technical field of precision casting, in particular to a cavity combustion engine filigree screw precision casting processing technology introducing an electron beam punching, which comprises a cavity combustion engine filigree screw pouring process preparation, and the cavity combustion engine filigree screw prepared through the pouring process preparation has the following structure: the cavity combustion engine filigree screw comprises a screw head and a screw rod arranged in an up-down mode; the screw head is provided with an inner plum blossom groove, and the screw head is internally provided with an annular cavity; the annular cavity is arranged outside the inner plum blossom groove; a gas passage arranged in a surrounding mode is arranged below the flange of the screw head, the gas passage penetrates into the annular cavity, thereby realizing the communication between the annular cavity and the outside; and the screw rod is internally provided with a hollow channel. Through laser punching equipment and electron beam hole expanding equipment, a plurality of tiny cooling hole channels with smooth inner walls are prepared on the filigree screw with a complex prefabricated cavity, the risk of local stress concentration caused by uneven heating or cooling is reduced, excellent connection reliability and overall structural strength can be maintained under a high-temperature and high-vibration environment.

Description

Technical Field

[0001] This invention relates to the field of precision casting technology, and in particular to a precision casting process for cavity gas turbine lace screws using electron beam drilling. Background Technology

[0002] A cavity gas turbine is a type of thermal engine that directly converts the heat energy released by the combustion of fuel in the combustion chamber into power. The internal operating temperature of its combustion chamber reaches over 1,000 degrees Celsius. To protect the combustion chamber shell, the inner wall of the combustion chamber is usually covered with metal or ceramic heat insulation tiles, which are fixed to the combustion chamber wall with screws.

[0003] However, the continuous high temperature and high pressure environment of the cavity gas turbine will cause the friction between the threaded pairs to decrease, which can easily lead to relative rotation and loosening of the screws. To solve this problem, hollow screws are often used in the prior art, and the screw temperature is reduced and the preload is maintained by cooling with internal airflow.

[0004] Referring to Chinese Patent Publication No. CN115962488B, a heat shield fixing structure and fixing method for a gas turbine combustion chamber are disclosed. By setting hollow screws, the cooling efficiency of the gas turbine combustion chamber is accelerated. Referring to Chinese Patent Publication No. CN116906936B, a fixing mechanism for combustion chamber bearings and a combustion chamber heat shield device are disclosed. By setting a through hole for air flow in the connecting screw, both the bearings and the screws themselves can be cooled, achieving synergistic cooling of the bearings and the screws themselves.

[0005] However, the hollow screws used in the above design all have simple through holes located in the middle of the screw.

[0006] It has the following shortcomings:

[0007] 1. The airflow in the hollow and breathable structure is too smooth, the flow rate is too fast, the residence time is short, and the energy loss is relatively large;

[0008] 2. Hollow, breathable holes are generally cast. Due to process limitations, it is difficult to make the hole diameter small and the inner wall smooth. This not only results in greater energy loss but also causes internal turbulence.

[0009] 3. Hollow, ventilated holes can reduce the fixing strength of the screws, posing a safety hazard under high vibration conditions. Summary of the Invention

[0010] The purpose of this invention is to provide a precision casting process for cavity gas turbine lace screws that incorporates electron beam drilling, in order to solve at least one of the above-mentioned technical problems.

[0011] The technical problem solved by the invention can be achieved using the following technical solutions:

[0012] A precision casting process for cavity gas turbine scalloped screws, incorporating electron beam drilling, is described. This process includes a casting procedure for preparing the cavity gas turbine scalloped screws, which, when manufactured using this casting procedure, have the following structure:

[0013] The cavity gas turbine scalloped screws consist of screw heads and screw rods arranged vertically.

[0014] The screw head has an inner perforated groove, and the screw head has an annular cavity inside;

[0015] An annular cavity surrounds the outer side of the inner plum blossom groove;

[0016] Below the flange of the screw head, there are vents arranged in a ring. The vents penetrate into the annular cavity, thereby completing the connection between the annular cavity and the outside.

[0017] The screw has a hollow channel inside, and the top of the screw has a hollow, trumpet-shaped flared structure with gradually increasing inner and outer cross-sectional areas. The hollow part of the trumpet-shaped flared structure is connected to the hollow channel.

[0018] The large end of the flared, trumpet-shaped structure is fixedly connected to the bottom of the screw head;

[0019] The screw head is provided with at least four holes arranged around the axis of the hollow channel;

[0020] At least four channels penetrate the screw head, the annular cavity, and communicate with the hollow part of the flared structure;

[0021] At least four channels face the outer portion of the bottom of the hollow part of the flared structure;

[0022] The process of creating the channel involves the following steps:

[0023] (a) Determine the preset positions of at least one channel according to the design requirements;

[0024] The laser beam of the laser drilling system performs laser drilling on the screw head along the preset position of the channel, forming an initial channel with a diameter of 70% to 90% of the preset diameter;

[0025] (ii) Prepare the electron beam reaming equipment, start the electron beam reaming equipment, and ream the hole to form a channel with a preset diameter and smooth inner wall.

[0026] Due to limitations in the casting process, the hollow screws used in the prior art have a large inner diameter of the vent hole, which occupies most of the screw's volume. Therefore, most screws use an external hexagonal head design to facilitate the application of tools such as socket wrenches. However, the external hexagonal head protrudes from the surface of the tile. In order not to disrupt the flow of high-temperature gas in the combustion chamber, the tile needs to be locally thickened or specially shaped to accommodate the external hexagonal head, which increases material consumption and processing costs.

[0027] In the above design of this patent application, a cavity gas turbine lace screw with an inner plum blossom groove is obtained through a casting process. By using a laser drilling device and an electron beam hole expansion device, a channel with a small diameter and smooth inner wall located next to the inner plum blossom groove is processed on the cavity gas turbine lace screw. This achieves efficient cooling without damaging the structural integrity of the inner plum blossom groove. The inner plum blossom groove allows the installation tool to be driven from inside the screw, so that the screw head can be embedded into the tile in a flush manner. The tile does not need to be thickened or specially shaped, achieving continuous and flat tile surface while reducing material consumption and processing costs.

[0028] In this invention, the cooling channels of the hollow gas turbine scalloped screw (at least four channels penetrating the screw head, the annular cavity, and communicating with the hollow part of the trumpet-shaped flared structure) are designed with variable cross-sections to achieve cooling medium flow rate regulation. After the cooling medium enters the large-volume annular cavity through the channels and vents, the flow rate decreases and is fully mixed. After being accelerated through the narrowed channels, it enters the hollow part of the trumpet-shaped flared structure and is decelerated and mixed again. The cooling medium forms a uniformly distributed and stable slow flow. Guided by the trumpet-shaped flared structure, the cooling medium enters the hollow channel smoothly and gently.

[0029] The hollow gas turbine scalloped screw has a uniform overall metal wall thickness. The annular cavity and flared structure extend the residence time of the cooling medium, allowing the slow and gentle flow of the cooling medium to make full and consistent contact with all parts of the metal inner wall of the hollow gas turbine scalloped screw. This ensures that the thermal expansion direction and proportion of the hollow gas turbine scalloped screw are consistent under high-temperature conditions, reducing the risk of local stress concentration caused by uneven heating or cooling. As a result, it can maintain excellent connection reliability and overall structural strength even in high-temperature and high-vibration environments.

[0030] Traditional manufacturing processes often fail to achieve small-diameter and smooth internal channels, making it difficult to apply small-diameter channels to scalloped screws for cavity gas turbines. Without the manufacturing process for small-diameter channels, traditional scalloped screws for cavity gas turbines struggle to achieve a good design for structural compactness, flatness, and the microstructure of the internal flow channels.

[0031] This patent first solves the manufacturing process of smooth channels with small diameter, and on this basis, it designs the flow channel, which can use cavity gas turbine lace screws with internal plum blossom grooves, thereby reducing production costs, improving heat exchange efficiency, uniform heat distribution, and maintaining excellent connection reliability and overall structural strength in high temperature and high vibration environments.

[0032] Preferably, the process for generating the channel specifically adopts the following steps:

[0033] (i) Determine the preset positions of at least 4 channels according to the design requirements. Below the preset positions of the channels, grooves generated during the casting process are provided.

[0034] (ii) Prepare a laser drilling device, embed a high-temperature resistant liner with a suitable shape into each groove, and provide a light-absorbing layer on the upper surface of the high-temperature resistant liner; arrange the high-temperature resistant liner corresponding to the lower end of the preset channel, and use the laser beam of the laser drilling system to perform laser drilling on the screw head along the preset position of the channel to form an initial channel with a hole diameter of 70% to 90% of the preset hole diameter, and remove the liner.

[0035] (iii) Prepare electron beam reaming equipment, including a high-voltage power supply for the electron beam reaming system;

[0036] High-temperature resistant electrode pieces with matching shapes are embedded in each groove, and each high-temperature resistant electrode piece is connected to the positive terminal of the high-voltage power supply.

[0037] And ground the scalloped screws of the cavity gas turbine;

[0038] Then, the electron beam reaming equipment is activated to ream the hole, forming a channel with a preset diameter and smooth inner wall.

[0039] In the above design, a pre-set groove is used during casting as a positioning reference for the high-temperature resistant liner and the high-temperature resistant electrode sheet. The cavity gas turbine lace screw is drilled along a preset path using a laser drilling device. That is, a high-energy laser beam is focused on the preset position of the screw through an optical focusing system, so that the material melts and vaporizes instantly to form an initial channel with a small aperture. A high-temperature resistant liner is installed at the lower end of the preset channel to intercept and absorb the remaining energy of the laser beam and reduce the risk of the screw wall being penetrated by the laser beam.

[0040] Laser high-temperature ablation will inevitably produce burrs and recast layers on the inner wall of the initial channel. Due to the narrow inner diameter and large depth-to-diameter ratio of the initial channel, these internal burrs are extremely difficult to be completely ground or removed in subsequent processing, resulting in the inner wall of the channel not achieving an ideal smooth state. After such screws with rough inner walls are installed in the combustion chamber and put into use, under high-temperature environment, the burrs and attached impurities on the inner wall are prone to peeling and accumulation under the action of thermal stress and fluid scouring, eventually causing partial or complete blockage of the cooling channel, affecting the safe operation of the engine.

[0041] By combining high-temperature resistant electrode sheets and electron beam hole-expanding equipment, the electron beam bombards the hole wall with plasma, expanding the initial hole while eliminating burrs and recast layers generated by laser processing on the hole wall. This results in a final hole with a preset diameter and a smooth inner wall, reducing the risk of debris accumulation and flow channel blockage. It also avoids energy loss and internal turbulence caused by rough hole walls. This not only improves the heat exchange efficiency and service life of the cavity gas turbine scallop screws but also reduces the risk of failure caused by the failure of the cavity gas turbine scallop screws, providing a guarantee for the long-term, safe, and stable operation of the cavity gas turbine.

[0042] Preferably, the high-temperature resistant gasket is an alumina gasket; the high-temperature resistant electrode sheet is a tungsten electrode sheet.

[0043] Preferably, the light-absorbing layer on the surface of the high-temperature resistant gasket is a graphite coating.

[0044] Preferably, the surface of the tungsten electrode sheet is sandblasted to form a rough surface with microscopic protrusions. The tungsten electrode sheet with the microscopic protrusions and rough surface forms uniformly distributed and stable discharge points, achieving uniform discharge, ensuring the consistency of hole wall processing, reducing the risk of abnormal discharge, and protecting the scalloped screws of the cavity gas turbine.

[0045] Preferably, the outer peripheral edge of the tungsten electrode sheet is covered with an insulating strip, which is inserted into and adapted to the groove.

[0046] Preferably, the insulating strip is made of aluminum nitride ceramic.

[0047] Preferably, the channel includes two coaxially arranged and connected from top to bottom; one of the segments connecting the outside to the annular cavity is called the outer hole; the other segment connecting the annular cavity to the hollow channel is called the inner hole; the outer hole, the annular cavity, the inner hole and the hollow channel are connected in series and are interconnected with the vent to form a cooling flow channel.

[0048] Preferably, there is a gap of 1mm to 5mm between the groove and the end of the inner hole.

[0049] In summary, the present invention has the following beneficial effects: This patent first solves the production process of smooth channels with small diameter, and on this basis, it conducts flow channel design, which achieves the effect of reducing production costs and maintaining excellent connection reliability and overall structural strength under high temperature and high vibration environment. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the overall structure of the precision casting process for the cavity gas turbine lace screws using electron beam drilling, as described in this invention.

[0051] Figure 2 This is a cross-sectional structural schematic diagram of the lace screw of the present invention, which incorporates the electron beam drilling precision casting process for cavity gas turbine lace screws.

[0052] In the diagram, 1 is the lace screw of the cavity gas turbine; 2 is the screw head; 3 is the screw rod; 4 is the inner plum blossom groove; 5 is the annular cavity; 6 is the vent; 7 is the trumpet-shaped flared structure; 8 is the channel; 9 is the groove; 10 is the outer hole; 11 is the inner hole; and 12 is the hollow channel. Detailed Implementation

[0053] To make the technical means, creative features, objectives and effects of the invention easier to understand, the invention will be further explained below with reference to specific illustrations.

[0054] refer to Figures 1 to 2 The precision casting process for cavity gas turbine scalloped screws, which introduces electron beam drilling, includes a casting process for preparing cavity gas turbine scalloped screw 1. The cavity gas turbine scalloped screw 1 manufactured by the casting process has the following structure:

[0055] The cavity gas turbine scalloped screw 1 includes screw heads 2 and screw rods 3 arranged vertically;

[0056] The screw head 2 has an inner plum blossom groove 4, and the screw head 2 has an annular cavity 5 inside;

[0057] The annular cavity 5 surrounds the outer side of the inner plum blossom groove 4;

[0058] A series of vents 6 are arranged around the flange of the screw head 2. The vents 6 penetrate into the annular cavity 5, thereby completing the connection between the annular cavity 5 and the outside.

[0059] The screw 3 has a hollow channel 12 inside, and the top of the screw 3 has a hollow trumpet-shaped flared structure 7 with gradually increasing inner and outer cross-sectional areas. The hollow part of the trumpet-shaped flared structure 7 is connected to the hollow channel 12.

[0060] The large end of the flared structure 7 is fixedly connected to the bottom of the screw head 2;

[0061] The screw head 2 is provided with at least four channels 8 arranged around the axis of the hollow channel 12;

[0062] At least four channels 8 penetrate the screw head 2 and the annular cavity 5 and are connected to the hollow part of the flared structure 7;

[0063] At least four channels 8 face the outer part of the bottom of the hollow portion of the trumpet-shaped flared structure 7;

[0064] The fabrication process of channel 8 involves the following steps:

[0065] (a) Determine the preset positions of at least four channels 8 according to the design requirements;

[0066] The laser beam of the laser drilling system performs laser drilling on the screw head 2 along the preset position of the channel 8, forming an initial channel with a hole diameter of 70% to 90% of the preset hole diameter;

[0067] (ii) Prepare the electron beam reaming equipment, start the electron beam reaming equipment, and ream the hole to form a channel 8 with a preset diameter and smooth inner wall.

[0068] Due to limitations in the casting process, the hollow screws used in the prior art have a large inner diameter of the vent hole, which occupies most of the screw's volume. Therefore, most screws use an external hexagonal head design to facilitate the application of tools such as socket wrenches. However, the external hexagonal head protrudes from the surface of the tile. In order not to disrupt the flow of high-temperature gas in the combustion chamber, the tile needs to be locally thickened or specially shaped to accommodate the external hexagonal head, which increases material consumption and processing costs.

[0069] In the above design of this patent application, a cavity gas turbine lace screw 1 with an inner plum blossom groove 4 is obtained through a casting process. By using a laser drilling device and an electron beam hole expansion device, a channel 8 with a small diameter and smooth inner wall located next to the inner plum blossom groove 4 is machined on the cavity gas turbine lace screw 1. This achieves efficient cooling without damaging the structural integrity of the inner plum blossom groove 4. The inner plum blossom groove 4 allows the installation tool to be driven from inside the screw, so that the screw head 2 can be embedded into the tile in a flush manner. The tile does not need to be thickened or specially shaped, achieving continuous and flat tile surface while reducing material consumption and processing costs.

[0070] In this invention, the cooling channels of the hollow gas turbine scalloped screw 1 (at least four channels 8 penetrating the screw head 2, the annular cavity 5 and communicating with the hollow part of the trumpet-shaped flared structure 7) are designed with variable cross-sections to achieve cooling medium flow rate regulation. After the cooling medium enters the large-volume annular cavity 5 through the channels 8 and the vent 6, the flow rate is reduced and fully mixed. After being accelerated through the narrowed channels 8, it enters the hollow part of the trumpet-shaped flared structure 7 and is decelerated and mixed again. The cooling medium forms a uniformly distributed and stable slow flow. After being guided by the trumpet-shaped flared structure 7, the cooling medium enters the hollow channel 12 smoothly and gently.

[0071] The hollow gas turbine scalloped screw 1 has a uniform overall metal wall thickness. The hollow parts of the annular cavity 5 and the flared structure 7 extend the residence time of the cooling medium, so that the slow and gentle flow of the cooling medium can make full and consistent contact with all parts of the metal inner wall of the hollow gas turbine scalloped screw 1. This makes the thermal expansion direction and proportion of the hollow gas turbine scalloped screw 1 consistent under high temperature conditions, reducing the risk of local stress concentration caused by uneven heating or cooling. Thus, it can still maintain excellent connection reliability and overall structural strength under high temperature and high vibration environment.

[0072] In traditional production, it is difficult to achieve a small diameter and smooth interior of the channel 8. Therefore, it is difficult to apply the small diameter channel 8 to the cavity gas turbine scallop screw 1. Without the production process of small diameter channel 8, it is difficult to design a good structure for compactness, flatness, and microstructure of internal flow channels.

[0073] This patent first solves the manufacturing process of the small-diameter smooth channel 8, and on this basis, it designs the flow channel, which can use the cavity gas turbine lace screw 1 with internal plum blossom groove 4, thereby reducing production costs, improving heat exchange efficiency, uniform heat distribution, and maintaining excellent connection reliability and overall structural strength in high temperature and high vibration environment.

[0074] The specific steps for forming channel 8 are as follows:

[0075] (i) Determine the preset positions of at least 4 channels 8 according to the design requirements. Below the preset positions of the channels 8, grooves 9 generated during the casting process are provided.

[0076] (ii) Prepare a laser drilling device, embed a high-temperature resistant liner with a suitable shape into each groove 9, and provide a light-absorbing layer on the upper surface of the high-temperature resistant liner; the high-temperature resistant liner is arranged corresponding to the lower end of the preset channel 8, and the laser beam of the laser drilling system performs laser drilling on the screw head 2 along the preset position of the channel 8 to form an initial channel with a hole diameter of 70% to 90% of the preset hole diameter, and remove the liner;

[0077] (iii) Prepare electron beam reaming equipment, including a high-voltage power supply for the electron beam reaming system;

[0078] High-temperature resistant electrode pieces with matching shapes are embedded in each groove 9, and each high-temperature resistant electrode piece is connected to the positive terminal of the high-voltage power supply.

[0079] And ground the cavity gas turbine scallop screw 1;

[0080] Then, the electron beam reaming equipment is activated to ream the hole and form a channel 8 with a preset diameter and smooth inner wall.

[0081] In the above design, a pre-set groove 9 is used as a positioning reference for the high-temperature resistant liner and the high-temperature resistant electrode sheet during casting. The cavity gas turbine lace screw 1 is drilled along a preset path by a laser drilling device. That is, the high-energy laser beam is focused on the preset position of the screw by an optical focusing system, so that the material melts and vaporizes instantly to form an initial channel with a small aperture. A high-temperature resistant liner is installed at the lower end of the preset channel 8 to intercept and absorb the remaining energy of the laser beam and reduce the risk of the screw wall being penetrated by the laser beam.

[0082] Laser high-temperature ablation will inevitably produce burrs and recast layers on the inner wall of the initial channel. Due to the narrow inner diameter and large depth-to-diameter ratio of the initial channel, these internal burrs are extremely difficult to be completely ground or removed in subsequent processing, resulting in the inner wall of the channel not achieving an ideal smooth state. After such screws with rough inner walls are installed in the combustion chamber and put into use, under high-temperature environment, the burrs and attached impurities on the inner wall are prone to peeling and accumulation under the action of thermal stress and fluid scouring, eventually causing partial or complete blockage of the cooling channel, affecting the safe operation of the engine.

[0083] By combining high-temperature resistant electrode sheets and electron beam hole-expanding equipment, the electron beam bombards the hole wall with plasma, expanding the initial hole while eliminating burrs and recast layers generated by laser processing on the hole wall. This results in a final hole with a preset diameter and a smooth inner wall, reducing the risk of debris accumulation and flow channel blockage. It also avoids energy loss and internal turbulence caused by rough hole walls. This not only improves the heat exchange efficiency and service life of the cavity gas turbine scallop screw 1, but also reduces the risk of failure caused by the failure of the cavity gas turbine scallop screw 1, providing a guarantee for the long-term, safe and stable operation of the cavity gas turbine.

[0084] The high-temperature resistant gasket is made of alumina; the high-temperature resistant electrode sheet is made of tungsten.

[0085] The light-absorbing layer on the surface of the high-temperature resistant gasket is a graphite coating.

[0086] The surface of the tungsten electrode sheet is sandblasted to form a rough surface with microscopic protrusions. The tungsten electrode sheet with the microscopic protrusions and rough surface forms uniformly distributed and stable discharge points, achieving uniform discharge, ensuring the consistency of hole wall processing, reducing the risk of abnormal discharge, and protecting the cavity gas turbine scalloped screw 1.

[0087] The outer periphery of the tungsten electrode sheet is covered with an insulating strip, which is inserted into and fits into the groove 9.

[0088] The insulating strip is made of aluminum nitride ceramic.

[0089] The channel 8 includes two coaxially arranged and connected from top to bottom; one of the channels connecting the outside to the annular cavity 5 is called the outer channel 10; the other channel connecting the annular cavity 5 to the hollow channel 12 is called the inner channel 11; the outer channel 10, the annular cavity 5, the inner channel 11 and the hollow channel 12 are connected in series and are interconnected with the vent 6 to form a cooling channel.

[0090] There is a gap of 1mm to 5mm between the groove 9 and the end of the inner hole 11. There is also a gap of 1mm to 5mm between the tungsten electrode sheet and the end of the inner hole 11. When the high-temperature resistant liner or the high-temperature resistant electrode sheet is embedded in the groove 9, a working gap of 1mm to 5mm is also formed between its working surface and the end of the inner hole 11. This allows the remaining energy of the laser beam to attenuate in the air after penetrating the screw head 2 and forming the initial channel 8. This allows the liner to absorb and intercept the remaining laser beam energy, reducing the risk of the laser beam penetrating the flared structure wall of the screw 3. It also facilitates the formation of a stable and concentrated electron beam that acts on the channel 8.

[0091] During production, the cavity gas turbine lace screw 1, which has a vent 6, an annular cavity 5, a trumpet-shaped flared structure 7 and a hollow threaded tube, is integrally formed by casting process. The cavity gas turbine lace screw 1 formed by casting process also has a groove 9 set below the preset channel 8.

[0092] A high-temperature resistant tungsten gasket is installed in the groove 9, which is the end of the laser processing. The cavity gas turbine lace screw 1 is laser drilled along the preset path by a laser drilling device to form an initial channel 8 with a hole diameter of 70% to 90% of the preset hole diameter. The tungsten gasket protects the thin-walled area of ​​the flared structure during laser drilling, and intercepts and absorbs the residual energy of the laser beam. After drilling is completed, the tungsten gasket is removed.

[0093] Next, the tungsten electrode sheet is installed in the groove 9. The tungsten electrode sheet is connected to the positive terminal of the high-voltage power supply through an insulated wire. The cavity gas turbine scallop screw 1 is grounded. The electron beam hole expansion device is started. The high-energy electron beam is guided and contacts the inner wall of the channel 8, so that the diameter of the channel 8 reaches the final size required by the design, and the burrs and recast layer generated by laser processing are eliminated, forming a high-quality final channel 8 with a smooth inner wall.

[0094] The foregoing has shown and described the basic principles, main features, and advantages of the invention. Those skilled in the art should understand that the invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made without departing from the spirit and scope of the invention, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection of the invention is defined by the appended claims and their equivalents.

Claims

1. A precision casting process for cavity gas turbine scalloped screws using electron beam drilling, comprising a casting process for preparing cavity gas turbine scalloped screws (1), characterized in that: The cavity gas turbine scalloped screw (1) manufactured by casting process has the following structure: The cavity gas turbine scalloped screw (1) includes a screw head (2) arranged on the top and bottom and a screw rod (3); The screw head (2) has an inner plum blossom groove (4), and the screw head (2) has an annular cavity (5); An annular cavity (5) surrounds the outer side of the inner plum blossom groove (4); A vent (6) is arranged around the flange of the screw head (2). The vent (6) penetrates into the annular cavity (5), thereby completing the connection between the annular cavity (5) and the outside. The screw (3) has a hollow channel (12) inside, and the top of the screw (3) has a hollow trumpet-shaped flared structure (7) with gradually increasing inner and outer cross-sectional areas. The hollow part of the trumpet-shaped flared structure (7) is connected to the hollow channel (12). The large end of the flared structure (7) is fixedly connected to the bottom of the screw head (2); The screw head (2) is provided with at least four holes (8) arranged around the axis of the hollow channel (12); At least four channels (8) penetrate the screw head (2), the annular cavity (5) and are connected to the hollow part of the flared structure (7); At least four channels (8) face the outer part of the bottom of the hollow portion of the flared structure (7); The process for forming the channel (8) involves the following steps: (a) Determine the preset positions of at least four channels (8) according to the design requirements; The laser beam of the laser drilling system performs laser drilling on the screw head (2) at a preset position along the channel (8) to form an initial channel with a hole diameter of 70% to 90% of the preset hole diameter; (ii) Prepare the electron beam reaming equipment, start the electron beam reaming equipment, and ream the hole to form a channel with a preset diameter and smooth inner wall (8).

2. The precision casting process for cavity gas turbine scalloped screws using electron beam drilling as described in claim 1, characterized in that: The specific steps for forming the channel (8) are as follows: (a) Determine the preset positions of at least 4 channels (8) according to the design requirements. Below the preset positions of the channels (8), there are grooves (9) generated during the casting process. (ii) Prepare a laser drilling device, embed a high-temperature resistant pad with a suitable shape into each groove (9), and provide a light-absorbing layer on the upper surface of the high-temperature resistant pad; the high-temperature resistant pad is arranged corresponding to the lower end of the preset channel (8), and the laser beam of the laser drilling system performs laser drilling on the screw head (2) along the preset position of the channel (8) to form an initial channel with a hole diameter of 70% to 90% of the preset hole diameter, and remove the pad; (iii) Prepare electron beam reaming equipment, including a high-voltage power supply for the electron beam reaming system; High-temperature resistant electrode pieces with matching shapes are embedded in each groove (9), and each high-temperature resistant electrode piece is connected to the positive terminal of the high-voltage power supply. And ground the cavity gas turbine scallop screw (1); Then, the electron beam reaming device is started to ream the hole and form a channel with a preset diameter and smooth inner wall (8).

3. The precision casting process for cavity gas turbine lace screws using electron beam drilling as described in claim 2, characterized in that: The high-temperature resistant gasket is an alumina gasket; The high-temperature resistant electrode sheet is a tungsten electrode sheet.

4. The precision casting process for cavity gas turbine scalloped screws using electron beam drilling as described in claim 2, characterized in that: The light-absorbing layer on the surface of the high-temperature resistant pad is a graphite coating.

5. The precision casting process for cavity gas turbine lace screws using electron beam drilling as described in claim 3, characterized in that: The surface of the tungsten electrode sheet is sandblasted to form a rough surface with microscopic protrusions.

6. The precision casting process for cavity gas turbine scalloped screws using electron beam drilling as described in claim 3, characterized in that: The outer periphery of the tungsten electrode sheet is covered with an insulating strip, which is inserted into the groove (9) and is adapted to the groove (9).

7. The precision casting process for cavity gas turbine scalloped screws using electron beam drilling as described in claim 6, characterized in that: The insulating strip is made of aluminum nitride ceramic.

8. The precision casting process for cavity gas turbine scalloped screws using electron beam drilling as described in claim 1, characterized in that: The channel (8) includes two coaxially arranged and connected from top to bottom; One of the segments that connects the outside to the annular cavity (5) is called the outer hole (10); Another segment connecting the annular cavity (5) and the hollow channel (12) is called the inner hole (11). The outer hole (10), the annular cavity (5), the inner hole (11) and the hollow channel (12) are connected in series and interconnected with the vent (6) to form a cooling channel.

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