CN115488585B - A method and device for manufacturing top first wall graphite mounting plate - Google Patents

Abstract

The present application belongs to the technical field of manufacturing magnetic confinement nuclear fusion devices, and specifically relates to a method and device for manufacturing a top first-wall graphite mounting plate to ensure the relative magnetic permeability, contour and long-term dimensional stability of the parts; the method comprises: selecting steel ingot raw materials to roll thick plates, cutting out a circular arc blank having a shape similar to the contour of the top first-wall graphite mounting plate in the thick plates, clamping one annular end face of the circular arc blank on a milling machine, milling out another annular end face, and processing a plurality of threaded holes on the other annular end face obtained by milling; using the plurality of threaded holes, mounting the other annular end face of the circular arc blank on a milling contour clamping tool, milling out the inner and outer contours of the circular arc blank and the contour of an annular end face; clamping the circular arc blank assembled and locked with the milling contour clamping tool together to complete the bolt through-hole processing on all contour surfaces; fine milling the circular arc blank to the final target contour to obtain the top first-wall graphite mounting plate.

Description

A method and device for manufacturing top first wall graphite mounting plate

Technical Field

The present application belongs to the technical field of manufacturing magnetic confinement nuclear fusion devices, and specifically relates to a method and device for manufacturing a top first wall graphite mounting plate.

Background technique

In a tokamak device, the wall material facing the plasma is usually referred to as the first wall. In the new generation of tokamaks, graphite is currently used as the wall material facing the plasma. The graphite is supported and fixed by a metal mounting plate made of 316L. Therefore, the shape and accuracy of the graphite mounting plate directly determine the spatial distribution position and positioning accuracy of the graphite.

The top first wall graphite mounting plate will be installed on the top of the inner cavity of the annular vacuum chamber with a D-shaped cross section, and will cover the 360° annular space of the entire top of the vacuum chamber around the central axis of the device. As shown in Figures 1 and 2, the outer contour of the top first wall graphite mounting plate 1 of the new generation tokamak device is composed of a circular arc and a plane, and its inner contour is composed of multiple spatial planes. Two bolt through holes 104 are opened on each small plane for the installation of graphite. The arc length of the entire top first wall graphite mounting plate 1 is greater than 1 meter, and its annular two end faces 101 and 102 are cut out by the angle surface passing through the central axis of the tokamak device, and the length and width of the annular maximum chord 103 reach 140mm. In order to ensure the installation accuracy of graphite, the contour of the entire inner contour composed of multiple planes must be less than 0.2mm, and it is required to remain unchanged for a long time. In addition, since the top first wall graphite mounting plate 1 is located in the strong magnetic field of the tokamak device, the relative magnetic permeability of the finished product is required to be less than 1.04.

Since the top first wall graphite mounting plate 1 has the characteristics of complex spatial shape, high dimensional accuracy requirements and strict magnetic permeability, it is manufactured for the first time in China and there is no mature processing experience to learn from.

Summary of the invention

The purpose of this application is to provide a method and device for manufacturing a top first wall graphite mounting plate, so as to solve the problem of how to manufacture a top first wall graphite mounting plate with complex spatial shape and high dimensional accuracy requirements.

Technical solution to achieve the purpose of this application:

A first aspect of an embodiment of the present application provides a method for manufacturing a top first wall graphite mounting plate, the method comprising:

Selecting steel ingot raw materials to roll thick plates, the thickness of the thick plates being greater than the maximum circumferential chord length of the top first wall graphite mounting plate;

Cutting out a circular arc blank having a shape similar to the outer contour of the top first wall graphite mounting plate from the thick plate, wherein the circumferential chord length of the circular arc blank is equal to the thickness of the thick plate;

Clamping one annular end face of the circular arc blank on a milling machine, milling out another annular end face, and processing a plurality of threaded holes at the midline position of the inner and outer arc contour wall thickness of the other annular end face milled out;

Using the plurality of threaded holes, the other annular end face of the arc blank is mounted on a milling profile clamping tool, and the inner and outer contours of the arc blank and the contour of an unclamped annular end face are milled out;

Clamp the arc blank assembled and locked with the milling contour clamping fixture onto the rotating platform of the CNC horizontal machining center to complete the bolt through-hole processing on all contour surfaces;

The arc blank is finely milled to the final target contour by using the milling contour clamping tool and the annular end face milling tool to obtain the top first wall graphite mounting plate.

Optionally, the step of selecting steel ingot raw materials to roll thick plates further comprises:

The thick plate is subjected to solution heat treatment, kept at 1050° C. to 1100° C. for 120 minutes, and then taken out of the furnace and water-cooled after the holding time is reached.

Optionally, the step of selecting steel ingot raw materials to roll thick plates specifically includes:

The steel ingot raw material is selected to be rolled into a thick plate by forging a slab and hot rolling. The thickness of the rolled thick plate is 10 mm longer than the maximum circumferential chord length of the top first wall graphite mounting plate.

Optionally, the step of cutting a circular arc blank having a shape similar to the outer contour of the top first wall graphite mounting plate in the thick plate further comprises:

The arc blank is subjected to heat treatment to eliminate stress, and is kept at 410° C. to 425° C. for 4 to 8 hours. After the holding time is reached, the blank is taken out of the furnace and air-cooled.

Optionally, the step of milling the inner and outer contours of the arc blank and the contour of an unclamped annular end face further includes:

The arc blank is subjected to heat treatment to eliminate stress, and is kept at 410° C. to 425° C. for 4 to 6 hours. After the holding time is reached, the blank is taken out of the furnace and air-cooled.

Optionally, the step of cutting a circular arc blank having a shape similar to the outer contour of the top first wall graphite mounting plate in the thick plate specifically includes:

The arc blank is cut out of the thick plate by wire cutting, and a single-side machining allowance of the outer contour of the arc blank is 3 mm to 5 mm.

Optionally, the method of using the milling contour clamping tool and the annular end face milling tool to fine-mill the arc blank to the final target contour to obtain the top first wall graphite mounting plate specifically includes:

Assembling the arc blank with the milling profile fixture, and using an integral coated rod milling cutter to mill the inner and outer contour surfaces of the arc blank in one pass cycle;

The arc blank is assembled with the annular end face milling tooling, and the annular end face with the threaded hole is processed to the final target contour by a vertical CNC machining center or a CNC gantry milling machine. The processed arc blank is clamped to remove the burrs to obtain the top first wall graphite mounting plate.

The second aspect of the embodiment of the present application provides a device for manufacturing a top first wall graphite mounting plate, which is applied to any method for manufacturing a top first wall graphite mounting plate provided in the first aspect of the embodiment of the present application; the device comprises: a milling shape clamping tool and a circumferential end face milling tool;

The platform plane of the milling shape clamping tool is fitted with the circumferential end surface of the arc blank with the threaded hole, and a through hole is opened on the platform plane, which coincides with the bolt hole position of the arc blank, for assembling the arc blank;

A workpiece mounting positioning surface is provided on the outer side of the annular end face milling tooling, and the contour size of the workpiece mounting positioning surface matches the theoretical size of the inner plane contour of the top first wall graphite mounting plate. Workpiece locking threaded holes are opened at corresponding positions of each small plane on the workpiece mounting positioning surface according to the hole positions of the theoretical model of the top first wall graphite mounting plate for locking the top first wall graphite mounting plate and the annular end face milling tooling.

Optionally, the milling contour clamping tool is provided with a positioning pin hole, and the arc blank is accurately positioned by installing a cylindrical pin in the positioning pin hole.

Optional,

A first coordinate system positioning hole is arranged on the platform plane of the milling profile clamping tool, and a first clamping and finding surface is arranged on the side of the milling profile clamping tool away from the arc blank, which is used to quickly determine the tool feed coordinate system and direction during processing;

A second coordinate system positioning hole and a second clamping and locating surface are provided on the plane of the annular end face milling tool, which are used to quickly align the direction of the annular end face milling tool and determine the processing coordinate system during processing.

The beneficial technical effects of this application are:

The embodiment of the present application manufactures the product's outer contour blank by rolling thick plates and then wire cutting, avoiding the serious internal stress and excessive magnetic permeability caused by thin plate profiling and welding, thereby reducing the deformation of the product during subsequent processing; by opening a threaded hole at one end of the workpiece and fixing it with a special milling tool, the rough milling and fine milling processes of the inner and outer contours can be completed on a three-axis CNC machine tool, and it has high processing efficiency and processing accuracy; the heat treatment process is reasonably arranged between each process, which fully eliminates the internal stress in the product processing process and improves the long-term dimensional stability of the final product. The present application has strong operability and high processing efficiency. The contour of the top first wall graphite mounting plate processed according to the method of the present application can be stably maintained within 0.2mm for a long time, and the magnetic permeability of all areas of the finished product is less than 1.04.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a top first wall graphite mounting plate of a tokamak device according to an embodiment of the present application;

FIG2 is a schematic diagram of the structure of a top first wall graphite mounting plate of another tokamak device in an embodiment of the present application;

FIG3 is a schematic flow chart of a method for manufacturing a top first wall graphite mounting plate provided in an embodiment of the present application;

FIG4 is a schematic diagram of cutting an arc blank in an embodiment of the present application;

FIG5 is a schematic diagram of processing a threaded hole in an embodiment of the present application;

FIG6 is a schematic structural diagram of a milling shape clamping tool in an embodiment of the present application;

FIG7 is a schematic structural diagram of a circumferential end face milling tool in an embodiment of the present application;

FIG8 is a schematic diagram of the assembly of a milling shape clamping tool and an arc blank in an embodiment of the present application;

FIG. 9 is a schematic diagram of the assembly of a circumferential end face milling tool and an arc blank in an embodiment of the present application.

In the figure:

1-top first wall graphite mounting plate; 101, 102-annular end faces; 103-annular maximum chord;

104-bolt through hole;

2-thick plate; 21-arc blank; 22-threaded hole;

3-milling shape clamping tooling; 31-platform plane; 32-through hole; 33-positioning pin hole; 34-cylindrical pin; 35-first coordinate system positioning hole; 36-first clamping front face;

4- circumferential end face milling tool; 41- workpiece mounting positioning surface; 42- workpiece locking threaded hole; 43- second coordinate system positioning hole; 44- second clamping and finding front surface.

Detailed ways

In order to make those skilled in the art better understand the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described below are only a part of the embodiments of the present application, not all. Based on the embodiments recorded in the present application, all other embodiments obtained by those skilled in the art without paying creative work are within the scope of protection of the present application.

To facilitate understanding, the specific structure of the top first wall graphite mounting plate involved in the embodiment of the present application is first introduced below.

As shown in FIG1 , the outer contour of the finished product of the top first wall graphite mounting plate 1 of the Tokamak device installed in the inner cavity of the vacuum chamber is composed of an arc and a plane, and the inner side is composed of various small planes to form a spatial contour shape. Two bolt through holes 104 are opened on each small plane for the installation and fixation of graphite. The wall thickness of the top first wall graphite mounting plate 1 varies from 15 mm to 25 mm.

Define OZ as the central axis of the tokamak device, and define the direction of rotating around the central axis of OZ as the circumferential direction. In the tokamak device, multiple top first-wall graphite mounting plates 1 are circumferentially spread over the top of the annular vacuum chamber of the D-shaped cross section of the tokamak device with the OZ axis as the center; as shown in FIG1 , define the circumferential end faces 101 and 102 of the top first-wall graphite mounting plate 1 as circumferential angle faces, and the circumferential end faces 101 and 102 are cut out by two angle faces passing through the central axis of OZ, so the closer to the OZ axis, the smaller the circumferential chord length value, and the farther away from the OZ axis, the larger the circumferential chord length value, and define the outermost circumferential chord length as the circumferential maximum chord 103, and the value of the circumferential maximum chord 103 is about 140 mm. Due to the characteristics of the top first-wall graphite mounting plate 1 having a complex spatial shape, high dimensional accuracy requirements, and strict magnetic permeability, it is manufactured for the first time in China, and there is no mature processing experience to learn from.

The embodiments of the present application provide a method and apparatus for manufacturing a top first wall graphite mounting plate to ensure the relative magnetic permeability, contour and long-term dimensional stability of the parts.

Based on the above content, in order to clearly and in detail illustrate the above advantages of the present application, the specific implementation methods of the present application will be described below in conjunction with the accompanying drawings.

Refer to Figure 3, which is a schematic flow chart of a method for manufacturing a top first wall graphite mounting plate provided in an embodiment of the present application.

A method for manufacturing a top first wall graphite mounting plate provided in an embodiment of the present application includes:

S101: Select steel ingot raw materials to roll thick plates 2.

In the embodiment of the present application, the thickness of the thick plate 2 is greater than the maximum circumferential chord length of the top first wall graphite mounting plate 1. As an example, the thickness of the rolled thick plate 2 is 10 mm longer than the maximum circumferential chord 103 of the top first wall graphite mounting plate 1.

In practical applications, steel ingot raw materials with qualified ingredients can be selected to roll thick plates 2 through forging slabs and hot rolling, which will not be listed here one by one.

In one example, in order to ensure the relative magnetic permeability of the top first wall graphite mounting plate 1, after step S101, the following steps may also be included:

The thick plate 2 is subjected to solution heat treatment at 1050°C to 1100°C for 120 minutes, and is taken out of the furnace and water-cooled after the insulation time is reached.

The relative magnetic permeability of the thick plate 2 rolled according to this step can be maintained below 1.04.

S102: Cut out a circular arc blank 21 in the thick plate 2 that has a shape similar to the outer contour of the top first wall graphite mounting plate 1 .

In the embodiment of the present application, as shown in FIG4 , the circumferential chord length of the arc blank 21 is equal to the thickness of the thick plate 2. It is understandable that in practical applications, a plurality of arc blanks 21 can be cut out of a thick plate 2, as shown in FIG4 . In order to facilitate subsequent processing, compared with the top first wall graphite mounting plate 1, the single-side machining allowance of the outer contour of the arc blank 21 cut out in this step can be 3 mm to 5 mm. In practical applications, arc blanks can be cut out of thick plates using wire cutting.

In some possible implementations of the embodiment of the present application, step S102 may further include:

The arc blank 21 is heat treated to eliminate stress, and is kept at 410℃～425℃ for 4 hours～8 hours, and then taken out of the furnace and air-cooled after the holding time is reached. The function of this step is to fully eliminate the internal stress generated in the thick plate 2 during the rolling production process and improve the dimensional stability of the arc blank 21.

S103: clamping one circumferential end face of the arc blank 21 on a milling machine, milling out the other circumferential end face, and processing a plurality of threaded holes 22 at the midline positions of the inner and outer arc contour wall thicknesses on the other circumferential end face milled out.

In the embodiment of the present application, as shown in FIG5 , a plurality of threaded holes 22 can be machined at the midline position of the inner and outer arc contour wall thickness on the milled annular end face. The threaded holes 22 machined in this step are used for end face mounting and locking in the subsequent rough milling and fine milling processes. The distance between the two threaded holes can be 25 mm to 50 mm.

In practical applications, one annular end face of the arc blank 21 can be clamped on a vertical CNC machining center or a CNC gantry milling machine workbench, and the other annular end face can be milled out and polished.

S104: Using a plurality of threaded holes 22, the other annular end face of the arc blank 21 is mounted on the milling profile clamping tool 3, and the inner and outer contours of the arc blank 21 and the contour of the unclamped annular end face are milled out;

This step is for rough milling of the outer contour. In practical applications, the inner and outer contours of the arc blank 21 and the outer contour of the unclamped annular end face can be milled out in one clamping on a vertical CNC machining center or a CNC gantry milling machine. The specific structure and assembly method of the milling contour clamping tool 3 will be described in detail later, so they will not be repeated here.

As an example, except for the threaded annular end face and hole, the outer contour of the arc blank 21 after rough milling is compared with the top first wall graphite mounting plate 1, and the subsequent single-side machining allowance of each surface for subsequent fine milling can be 0.6mm to 0.8mm.

In some possible implementations of the embodiments of the present application, in order to eliminate thermal stress, step S104 may also include: heat treating the arc blank 21 to eliminate stress, keeping it at 410℃~425℃ for 4 hours to 6 hours, and taking it out of the furnace and air cooling it after the holding time.

S105: clamping the arc blank 21 assembled and locked with the milling contour clamping tool 3 onto the rotating platform of the CNC horizontal machining center to complete the processing of the bolt through holes 104 on all contour surfaces;

In the embodiment of the present application, the arc blank 21 that has completed step S104 is assembled and locked with the milling contour clamping tool 3 by means of threaded holes 22, and clamped together on the rotating platform of the CNC horizontal machining center. The rotating platform used in this step and the main machine of the machining center can realize CNC linkage, and the hole processing program of the top first wall graphite mounting plate 1 is generated according to the theoretical model through UG or other CNC machining three-dimensional software to complete the processing of the bolt through holes 104 on all contour surfaces. The bolt through holes 104 are processed before the inner and outer contour surfaces are finely processed to prevent the deformation of the contour surface caused by the bolt through holes 104 processing after the inner and outer contour surfaces are finely milled, which helps to improve the final contour of the finished product.

S106: using the milling contour clamping tool 3 and the circumferential end face milling tool 4, the arc blank 21 is finely milled to the final target contour to obtain the top first wall graphite mounting plate 1.

In some possible implementations of the embodiment of the present application, step S106 may specifically include:

Assemble the arc blank 21 with the milling profile fixture 3, and use the integral coated rod milling cutter to mill the inner and outer contour surfaces of the arc blank 21 in one pass cycle;

The arc blank 21 is assembled with the annular end face milling tool 4, and the annular end face with the threaded hole 22 is processed to the final target contour by a vertical CNC machining center or a CNC gantry milling machine. The processed arc blank 21 is clamped and the burrs are removed to obtain the top first wall graphite mounting plate 1.

In the embodiment of the present application, the arc blank 21 that has completed step S105 can be first unloaded from the horizontal machining center together with the assembly state maintained by the milling contour clamping tool 3, and then re-mounted on the vertical machining center or CNC gantry milling machine to fine-mill the contour to the theoretical target size, including the contour of the unclamped annular end face. In the final finishing process of the inner and outer contour surfaces, the integral coated rod milling cutter is used to polish the inner and outer contour surfaces of the arc blank 21 in one pass cycle, so as to obtain better finished product shape accuracy and surface roughness. After this step of processing, except for the unprocessed threaded clamping end face of the arc blank 21, the remaining surfaces are processed to the final theoretical size.

Then, the arc blank 21 is assembled with the annular end face milling tool 4, and the annular end face with the threaded hole 22 is processed to the final target contour by a vertical CNC machining center or a CNC gantry milling machine, and then the nipper is repaired to remove the burrs. After this step of processing, the arc blank 21 is processed into the final finished product size of the top first wall graphite mounting plate 1. In practical applications, the contour end face profiling program can be generated by UG and other three-dimensional processing software to achieve precision processing of the annular end face.

The embodiment of the present application manufactures the product's outer contour blank by rolling thick plates and then wire cutting, avoiding the serious internal stress and excessive magnetic permeability caused by thin plate profiling and welding, thereby reducing the deformation of the product during subsequent processing; by opening a threaded hole at one end of the workpiece and fixing it with a special milling tool, the rough milling and fine milling processes of the inner and outer contours can be completed on a three-axis CNC machine tool, and it has high processing efficiency and processing accuracy; the heat treatment process is reasonably arranged between each process, which fully eliminates the internal stress in the product processing process and improves the long-term dimensional stability of the final product. The present application has strong operability and high processing efficiency. The contour of the top first wall graphite mounting plate processed according to the method of the present application can be stably maintained within 0.2mm for a long time, and the magnetic permeability of all areas of the finished product is less than 1.04.

Based on the method for manufacturing a top first-wall graphite mounting plate provided in the above-mentioned embodiments, an embodiment of the present application also provides a device for manufacturing a top first-wall graphite mounting plate, which is applied to any one of the methods for manufacturing a top first-wall graphite mounting plate provided in the above-mentioned embodiments.

Refer to Figures 6 and 7, which are schematic structural diagrams of an apparatus for manufacturing a top first wall graphite mounting plate provided in an embodiment of the present application.

The embodiment of the present application provides a device for manufacturing a top first wall graphite mounting plate, comprising: a milling shape clamping tool 3 and a circumferential end face milling tool 4;

The platform plane 31 of the milling shape clamping tool 3 is fitted with the circumferential end surface of the arc blank 21 having the threaded hole 22, and a through hole 32 is opened on the platform plane 31, which coincides with the bolt hole 22 of the arc blank 21, for assembling the arc blank 21;

A workpiece mounting positioning surface 41 is provided on the outer side of the annular end face milling tool 4, and the contour size of the workpiece mounting positioning surface 41 matches the theoretical size of the inner plane contour of the top first wall graphite mounting plate 1, and workpiece locking threaded holes 42 are opened at the corresponding positions of each small plane on the workpiece mounting positioning surface 41 according to the hole positions of the theoretical model of the top first wall graphite mounting plate 1 for locking the top first wall graphite mounting plate 1 and the annular end face milling tool 4.

It can be understood that the threaded annular end face of the arc blank 21 is in contact with the platform plane 31 of the milling contour clamping tool 3, the threaded hole 22 of the arc blank 21 coincides with the through hole 32 of the milling contour clamping tool 3, and the arc blank 21 is assembled and locked by tightening the end face of the workpiece with bolts, as shown in Figure 8.

In the embodiment of the present application, a mounting surface 41 is provided on the outside of the annular end face milling tool 4, and the contour size of the mounting surface 41 is processed according to the theoretical size of the inner plane contour of the top first wall graphite mounting plate 1, and workpiece locking threaded holes 42 are provided at the corresponding positions of each small plane on the mounting surface 41 according to the hole positions of the theoretical model of the top first wall graphite mounting plate 1 for locking the workpiece and the tool. During assembly, the inner plane contour of the arc blank 21 is evenly and tightly fitted with the mounting surface 41 of the annular end face milling tool 4, and is locked with bolts, as shown in FIG9 .

In some possible implementations of the embodiments of the present application, a positioning pin hole 33 is provided on the milling contour clamping tool 3, and the arc blank 21 is precisely positioned by installing a cylindrical pin 34 in the positioning pin hole 33.

As an example, there are three locating pin holes 33, two of which are located at the inner contour position, and the third locating pin hole 33 is located at the plane corner of the outer arc, and the arc blank 21 is accurately positioned by the cylindrical pin 34. In actual operation, the workpieces with different machining allowances can be positioned by changing the outer diameter of the cylindrical pin 25.

In some possible implementations of the present application, a first coordinate system positioning hole 35 is provided on the platform plane 31 of the milling profile clamping tool 3, and a first clamping and finding surface 36 is provided on the side of the milling profile clamping tool 3 away from the arc blank 21, which is used to quickly determine the tool feed coordinate system and direction during processing;

A second coordinate system positioning hole 43 and a second clamping alignment surface 44 are provided on the plane of the annular end face milling tool 4 for quickly aligning the direction of the annular end face milling tool 4 and determining the machining coordinate system during machining.

In practical applications, the relative position relationship between the first coordinate system positioning hole 35 and the first clamping and locating face 36, the through hole 32 and the positioning pin hole 33 is determined by simulating the theoretical shape and position of the top first wall graphite mounting plate 1 with UG three-dimensional software. During processing, the machining tool coordinate system and direction can be quickly determined by aligning the milling shape clamping fixture 3. The circular arc blank 21 can be quickly installed, positioned and aligned by assembling the circumferential end face of the circular arc blank 21 with the milling shape clamping fixture 3, avoiding the replacement of the clamping plate during the milling process, resulting in multiple tool changes and reducing the machining accuracy and efficiency, and ensuring the machining accuracy and efficiency of the inner and outer contours and hole machining of the circular arc blank 21.

The present application is described in detail above in conjunction with the accompanying drawings and embodiments, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present application. Any content not described in detail in the present application can adopt the existing technology.

Claims (9)

1. A method for manufacturing a top first wall graphite mounting plate, characterized in that the method comprises: Selecting steel ingot raw materials to roll thick plates, the thickness of the thick plates being greater than the maximum circumferential chord length of the top first wall graphite mounting plate; Cutting out a circular arc blank having a shape similar to the outer contour of the top first wall graphite mounting plate from the thick plate, wherein the circumferential chord length of the circular arc blank is equal to the thickness of the thick plate; Clamping one annular end face of the circular arc blank on a milling machine, milling out another annular end face, and processing a plurality of threaded holes at the midline position of the inner and outer arc contour wall thickness of the other annular end face milled out; Using the plurality of threaded holes, the other annular end face of the arc blank is mounted on a milling profile clamping tool, and the inner and outer contours of the arc blank and the contour of an unclamped annular end face are milled out; Clamp the arc blank assembled and locked with the milling contour clamping fixture onto the rotating platform of the CNC horizontal machining center to complete the bolt through-hole processing on all contour surfaces; Using the milling contour clamping tool and the annular end face milling tool, the arc blank is finely milled to the final target contour to obtain the top first wall graphite mounting plate; The method of using the milling contour clamping fixture and the annular end face milling fixture to finely mill the arc blank to the final target contour to obtain the top first wall graphite mounting plate specifically includes: Assembling the arc blank with the milling profile fixture, and using an integral coated rod milling cutter to mill the inner and outer contour surfaces of the arc blank in one pass cycle; The arc blank is assembled with the annular end face milling tooling, and the annular end face with the threaded hole is processed to the final target contour by a vertical CNC machining center or a CNC gantry milling machine. The processed arc blank is clamped to remove the burrs to obtain the top first wall graphite mounting plate. 2. The method for manufacturing the top first wall graphite mounting plate according to claim 1, characterized in that the steel ingot raw material is selected to roll a thick plate, and then further comprises: The thick plate is subjected to solution heat treatment, kept at 1050° C. to 1100° C. for 120 minutes, and then taken out of the furnace and water-cooled after the holding time is reached. 3. The method for manufacturing the top first wall graphite mounting plate according to claim 1, characterized in that the step of selecting the steel ingot raw material to roll the thick plate specifically comprises: The steel ingot raw material is selected to be rolled into a thick plate by forging a slab and hot rolling. The thickness of the rolled thick plate is 10 mm greater than the maximum circumferential chord length of the top first wall graphite mounting plate. 4. The method for manufacturing a top first wall graphite mounting plate according to claim 1, characterized in that the arc blank having a shape similar to the outer contour of the top first wall graphite mounting plate is cut out of the thick plate, and then further comprising: The arc blank is subjected to heat treatment to eliminate stress, and is kept at 410° C. to 425° C. for 4 to 8 hours. After the holding time is reached, the blank is taken out of the furnace and air-cooled. 5. The method for manufacturing a top first wall graphite mounting plate according to claim 1, characterized in that after milling out the inner and outer contours of the arc blank and the contour of an unclamped annular end face, it also includes: The arc blank is subjected to heat treatment to eliminate stress, and is kept at 410° C. to 425° C. for 4 to 6 hours. After the holding time is reached, the blank is taken out of the furnace and air-cooled. 6. The method for manufacturing the top first wall graphite mounting plate according to claim 1, characterized in that the arc blank with a shape similar to the outline of the top first wall graphite mounting plate is cut out of the thick plate, specifically comprising: The arc blank is cut out of the thick plate by wire cutting, and a single-side machining allowance of the outer contour of the arc blank is 3 mm to 5 mm. 7. A device for manufacturing a top first wall graphite mounting plate, characterized in that it is applied to the method for manufacturing a top first wall graphite mounting plate according to any one of claims 1 to 6; the device comprises: a milling shape clamping tool and a circumferential end face milling tool; The platform plane of the milling shape clamping tool is fitted with the circumferential end surface of the arc blank with the threaded hole, and a through hole is opened on the platform plane, which coincides with the bolt hole position of the arc blank, for assembling the arc blank; A workpiece mounting positioning surface is provided on the outer side of the annular end face milling tooling, and the contour size of the workpiece mounting positioning surface matches the theoretical size of the inner plane contour of the top first wall graphite mounting plate. Workpiece locking threaded holes are opened at corresponding positions of each small plane on the workpiece mounting positioning surface according to the hole positions of the theoretical model of the top first wall graphite mounting plate for locking the top first wall graphite mounting plate and the annular end face milling tooling. 8. The device for manufacturing the top first wall graphite mounting plate according to claim 7 is characterized in that a positioning pin hole is provided on the milling shape clamping tooling, and the arc blank is accurately positioned by installing a cylindrical pin in the positioning pin hole. 9. The apparatus for manufacturing a top first wall graphite mounting plate according to claim 7, characterized in that: A first coordinate system positioning hole is arranged on the platform plane of the milling profile clamping tool, and a first clamping and finding surface is arranged on the side of the milling profile clamping tool away from the arc blank, which is used to quickly determine the tool feed coordinate system and direction during processing; A second coordinate system positioning hole and a second clamping and aligning surface are provided on the plane of the annular end face milling tool, which are used to quickly align the direction of the annular end face milling tool and determine the processing coordinate system during processing.