A method for manufacturing a curved part of a TF coil box

Abstract

The application relates to a preparation method of a TF coil box arc-shaped component and belongs to the technical field of TF coil boxes, which solves the problems of low material utilization and low efficiency of the existing TF coil box arc-shaped component preparation method. The preparation method comprises the following steps: preparing a side plate forge piece: opening and forging a steel ingot; plate blank forging, a pair of plate blanks are forged, one side of each plate blank has a multi-step structure, and the other side is a plane; the faces with the multi-step structure of the two plate blanks are placed opposite to each other, and the steps corresponding to the maximum cross sections of the two plate blanks are assembled and welded, and the assembly after assembly and welding is a symmetrical assembly; the symmetrical assembly is bent and formed; the steps corresponding to the maximum cross sections of the two plate blanks are split, each multi-step structure plate blank after splitting is processed into a slope surface structure of a TF coil box side plate, and a pair of TF coil box side plates are obtained; a bottom plate is prepared; and the bottom plate is welded with the pair of side plates. The method has high material utilization and high efficiency.

Description

Technical Field

[0001] This invention relates to the field of TF coil box technology, and in particular to a method for preparing an arc-shaped component of a TF coil box. Background Technology

[0002] Fusion reactors, due to their abundant fuel resources, lack of environmental pollution, and absence of radioactive waste, represent a crucial pathway to ultimately solving energy and environmental problems. The TF coil box, a core component of fusion reactor equipment, comprises multiple large-sized, variable-section arc-shaped components, typically constructed from low-temperature resistant, non-magnetic austenitic stainless steel forgings. The variable cross-section and complex shape of these arc-shaped components, coupled with the inherent high deformation resistance and poor thermoplasticity of the austenitic stainless steel material, make it extremely difficult to achieve precise forming of the complex, irregularly shaped austenitic stainless steel forgings used in fusion reactors.

[0003] like Figure 11 As shown, the arc-shaped component of the TF coil box includes two side plates and a base plate, and the outer sides of the two side plates each have a sloping structure. The existing method for manufacturing the arc-shaped component of the TF coil box is as follows: two side plates and a base plate are prepared separately, and then the two side plates and the base plate are welded together. The side plates are manufactured using a large-margin, overlay forging method. First, a rectangular steel ingot is prepared, and then the rectangular steel ingot is bent to form an arc shape (e.g., ...). Figure 13 As shown, the steel ingot is then forged into a sloping structure, resulting in a forged blank with a simple shape. Finally, excess material is removed by machining. This method results in a large amount of steel ingot waste, low material utilization, and high cost. Furthermore, this method only produces one side plate at a time, leading to low efficiency. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a method for preparing an arc-shaped component of a TF coil box to solve at least one of the following problems of the existing method: (1) large processing allowance, low material utilization rate and high cost, (2) only one side plate is made at a time, which is inefficient.

[0005] This invention provides a method for preparing an arc-shaped component of a TF coil box, the method comprising:

[0006] Step 1: Make the side panels:

[0007] Step 101: Forging the steel ingot;

[0008] Step 102: Slab forging, forging a pair of slabs, each slab having a multi-step structure on one side and a flat surface on the other side;

[0009] Step 103: Place the two slabs with multi-step structures face to face, and weld the steps corresponding to the largest cross sections of the two slabs together. The assembled component is a symmetrical component.

[0010] Step 104: Bend the symmetrical component into shape;

[0011] Step 105: Divide the steps corresponding to the maximum cross-section of the two slabs, and then process the multi-step structure of each slab into the slope structure of the TF coil box side plate to obtain a pair of TF coil box side plates.

[0012] Step 2: Make the base plate;

[0013] Step 3: Weld the base plate to a pair of side plates.

[0014] Preferably, the multi-step structure is a multi-step structure that extends from one end of the slab to the other end and the step height gradually decreases.

[0015] Preferably, in the multi-step structure, the height difference between two adjacent steps is 45-55mm.

[0016] Preferably, in step 102, the forging ratio of each step in the multi-step structure is not less than 1.3.

[0017] Preferably, step 2 includes:

[0018] Step 201: Forging the steel ingot;

[0019] Step 202: Forging a rectangular cross-section slab;

[0020] Step 203: Bend the rectangular cross-section blank to obtain the base plate of the arc-shaped component of the TF coil box.

[0021] Preferably, the bending forming process in step 104 is performed using a side plate bending die;

[0022] The side plate bending mold includes an upper mold and a lower mold, and the side of the upper mold opposite to the lower mold is an arc surface;

[0023] The lower mold includes a square base and columns disposed at the four corners of the base, with a groove provided on each column.

[0024] Preferably, the bending forming process in step 203 is performed using a base plate bending die;

[0025] The base plate bending mold includes an upper mold and a lower mold, and the side of the upper mold opposite to the lower mold is an arc surface;

[0026] The lower mold includes a square base and columns located at the four corners of the base.

[0027] Preferably, in steps 101 and 201, the steel ingot is subjected to homogenization heat treatment before forging.

[0028] Preferably, the homogenization heat treatment adopts a stepped heating method, including: a first temperature step of 840-860℃, a second temperature step of 1050-1060℃, and a third temperature step of 1200-1220℃.

[0029] Preferably, before bending the symmetrical component in step 104 and bending the rectangular cross-section slab in step 203, the symmetrical component and the rectangular cross-section slab are respectively kept at a temperature below the secondary recrystallization temperature.

[0030] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0031] 1. The method of this invention first forges a steel ingot into a slab with a multi-step structure on one side, then welds two slabs together to form a symmetrical assembly, then bends the symmetrical assembly into shape, and finally disassembles it, processing the multi-step structure of each slab into the slope structure of the side plate of the TF coil box. The slab with the multi-step structure is closer to the shape of the final part, which can effectively improve material utilization and reduce subsequent machining allowance.

[0032] 2. In the method of the present invention, a pair of TF coil box side plates can be prepared in one bending and forming process, which improves production efficiency.

[0033] 3. This invention welds two single asymmetrical slabs into a symmetrical assembly, and then bends and forms it, which can effectively solve the problem of bending instability of a single asymmetrical slab and improve the accuracy of the parts.

[0034] 4. This invention improves the grain refinement of forgings by performing step-by-step homogenization heat treatment on side plates and bottom plates, limiting upsetting and drawing parameters, and heating and holding the forgings below the secondary recrystallization temperature before bending and forming. This results in better thermoplasticity of the forgings and thus improves forging accuracy.

[0035] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0036] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0037] Figure 1This refers to the ingot homogenization heat treatment process in steps 101 and 201 of the present invention.

[0038] Figure 2 This refers to the forging process in step 101 and the multi-step slab forging process in step 102 of the present invention.

[0039] Figure 3 The slab forging with a multi-step structure obtained in step 102 of this invention;

[0040] Figure 4 This refers to the symmetrical component obtained by welding two slabs together in step 103 of the present invention.

[0041] Figure 5 This refers to step 104 of the present invention, which involves bending and shaping the symmetrical component.

[0042] Figure 6 This is a schematic diagram of step 105 of the present invention, which involves splitting the two side plate blanks.

[0043] Figure 7 This is a schematic diagram of step 105 of the present invention, which shows the process of machining the multi-step structure of the slab into a slope.

[0044] Figure 8 The process of forging the steel ingot in step 201 and forging the rectangular cross-section slab in step 202;

[0045] Figure 9 The process of bending and forming the rectangular cross-section slab in step 203 and the base plate bending mold;

[0046] Figure 10 A schematic diagram of the weld resistance assembly of the two side plates and the bottom plate;

[0047] Figure 11 This is a structural schematic diagram of the arc-shaped component of the TF coil box;

[0048] Figure 12 This is a schematic diagram of the side plate bending mold structure.

[0049] Figure 13 This is a flowchart of a side plate preparation method in the prior art;

[0050] Figure 14 Schematic diagram of slab assembly welding in step 103 of this invention;

[0051] Figure 15 Metallographic photographs of the forgings were obtained in Embodiment 1 of the present invention.

[0052] Figure label:

[0053] 1-Upper mold (side plate bending mold); 2-Lower mold (side plate bending mold); 201-Square base (side plate bending mold); 202-Column (side plate bending mold); 203-Groove (side plate bending mold); 3-Upper mold (base plate bending mold); 4-Lower mold (base plate bending mold); 401-Square base (base plate bending mold); 402-Column (base plate bending mold). Detailed Implementation

[0054] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0055] like Figure 11 As shown, the arc-shaped component of the TF coil box includes two side plates and a base plate, forming a symmetrical structure. The two side plates are perpendicular to the same surface of the base plate, and the long sides of the two side plates are connected to the long sides of the base plate. Both side plates and the base plate have curved arc-shaped structures. Each side plate has a sloping structure on its outer side, making each side plate a variable cross-section asymmetrical structure.

[0056] This invention provides a method for preparing the arc-shaped component of a TF coil box, such as... Figures 1-12 and Figure 14 As shown, the preparation method includes:

[0057] The preparation method includes:

[0058] Step 1: Make the side panels:

[0059] Step 101: Forging the steel ingot;

[0060] Step 102: Slab forging, forging a pair of slabs, each slab having a multi-step structure on one side and a flat surface on the other side; as shown Figure 2 and 3 As shown;

[0061] Step 103: Place the two slabs with multi-step structures facing each other, and weld the steps corresponding to the largest cross-sections of the two slabs together. The resulting assembly is a symmetrical assembly; for example... Figure 4 As shown;

[0062] Step 104: Bend the symmetrical component into shape; as shown Figure 5 As shown;

[0063] Step 105: Break down the steps corresponding to the maximum cross-sections of the two slabs, and then process the multi-step structure of each slab into a sloped structure for the TF coil box side plate, resulting in a pair of TF coil box side plates; For example... Figure 6 and Figure 7 As shown;

[0064] Step 2: Make the base plate; such as Figure 8 and Figure 9 As shown;

[0065] Step 3: Weld the base plate to the pair of side plates, as follows: Figure 10 and Figure 11 As shown.

[0066] Compared with existing technologies, the method of this invention first forges a steel ingot into a slab with a multi-step structure on one side, then welds two slabs together to form a symmetrical assembly, then bends the symmetrical assembly, and finally disassembles it, processing the multi-step structure of each slab into the slope structure of the TF coil box side plate. The multi-step structure of the slab is closer to the final part shape, which can effectively improve material utilization and reduce subsequent processing allowances. In the method of this invention, a pair of TF coil box side plates can be produced in one bending process, improving production efficiency. This invention welds two single asymmetrical slabs together to form a symmetrical assembly, and then bends it, which can effectively solve the problem of bending instability of a single asymmetrical slab and improve the accuracy of the part.

[0067] It should be noted that the multi-step structure is a multi-step structure that extends from one end of the slab to the other end and the step height gradually decreases, such as... Figure 3 As shown, multi-step slab shapes more closely resemble the final part shape, effectively improving material utilization and reducing subsequent machining allowances.

[0068] Specifically, the height difference between adjacent steps in the multi-step structure can be determined based on the slope of the arc-shaped component of the TF coil box to achieve the minimum machining allowance.

[0069] For example, in the multi-step structure, the height difference between two adjacent steps is 45-55mm, such as 46mm, 47mm, 48mm, 49mm, 50mm, 51mm, 52mm, 53mm, 54mm, etc.

[0070] For example, the side plate and bottom plate are low-temperature resistant non-magnetic austenitic stainless steel forgings. Austenitic stainless steel itself has characteristics such as high deformation resistance and poor thermoplasticity, which makes it difficult to achieve precise forming of irregularly shaped and complex austenitic stainless steel forgings for the arc-shaped components of the TF coil box.

[0071] For example, the side plate and the bottom plate are made of N50 material.

[0072] In this invention, in order to promote the precise forming of the side plate and bottom plate of the arc-shaped component of the TF coil box, in steps 101 and 201, the steel ingot is first subjected to homogenization heat treatment before the steel ingot is forged.

[0073] Specifically, such as Figure 1 As shown, the homogenization heat treatment adopts a stepped heating method, including: a first temperature step of 840-860℃, a second temperature step of 1050-1060℃, and a third temperature step of 1200-1220℃.

[0074] It should be noted that insulation is performed at each temperature step, and the insulation time is determined based on the smallest cross-section. The minimum insulation time is determined at one hour per 80mm, and the maximum insulation time is determined at one hour per 50mm.

[0075] Specifically, the first temperature step is the point of abrupt change in the coefficient of thermal expansion. After holding and homogenizing at this temperature, the temperature is raised to the second temperature step. Holding and homogenizing at the second temperature step does not cause significant grain growth. Then, holding at a high temperature at the third temperature step provides the necessary conditions for sufficient deformation during the initial forging. Furthermore, the homogenization heat treatment uses a stepped heating method, and holding at the first and second temperature steps for a period of time allows segregated elements to pre-diffuse, avoiding initial melting at grain boundaries. Raising to the third temperature step and holding for a certain period of time gradually eliminates segregation and dendrites, improves the thermoplasticity of austenitic stainless steel, reduces forging cracks, and enables precise forging with small allowances.

[0076] Furthermore, removing slag grooves from the surface of the steel ingot before the homogenization heat treatment can effectively prevent subsequent forging cracking caused by slag grooves.

[0077] For example, such as Figure 2 As shown, in step 101, the initial forging includes at least one upsetting deformation and at least one drawing deformation. Initial forging primarily breaks down the as-cast structure of the steel ingot, generating a large number of dislocations and slips, which is more conducive to element diffusion, further eliminates segregation, and further improves the hot plasticity of austenitic stainless steel.

[0078] For example, the forging ratio of the upsetting deformation in step 101 is not less than 1.7 (e.g., 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, etc.), and the final forging temperature is higher than 900℃ (e.g., 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, etc.). A forging ratio of 1.7 or higher ensures sufficient large deformation and meets the requirement of fine and uniform grains; a final forging temperature higher than 900℃ is to avoid cracking, as the tendency to crack would increase if the temperature were lower than 900℃.

[0079] It should be noted that before the forged billet is returned to the furnace after upsetting deformation, it is wrapped with an asbestos anvil. The purpose is to maintain the temperature during forging, prevent the temperature from dropping too quickly during the forging process, and extend the effective forging time. After the heat preservation is completed, a wide and flat anvil is used for elongation deformation.

[0080] For example, in step 101, the forging ratio for the elongation deformation is not less than 1.7 (e.g., 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, etc.), and the final forging temperature is higher than 900℃ (e.g., 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, etc.). Before returning the billet to the furnace, the forging billet is wrapped with an asbestos anvil to maintain the temperature during forging, prevent the temperature from dropping too quickly during the forging process, and extend the effective forging time. A forging ratio of 1.7 or higher can ensure sufficient large deformation and meet the requirement of fine and uniform grains; a final forging temperature higher than 900℃ is to avoid cracking, as the tendency to crack would increase if the temperature were lower than 900℃.

[0081] For example, in step 102, a pair of multi-step shaped slabs are drawn out using upper and lower flat anvils. The forging ratio of each step in the multi-step structure is not less than 1.3, for example, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, etc., to meet the critical deformation amount for dynamic recrystallization of the material and achieve grain refinement.

[0082] For example, in step 103, the welding method includes: machining 10×10mm welding bevels on the four sides of the corresponding welding surface, and then butt-welding the two slabs together, such as... Figure 14 As shown.

[0083] For example, to facilitate hoisting, step 103 further includes welding lifting lugs to both ends of the two slabs that make up the symmetrical assembly.

[0084] For example, the bending forming process in step 104 is performed using a side plate bending die;

[0085] Specifically, such as Figure 12 As shown, the side plate bending mold includes an upper mold 1 and a lower mold 2;

[0086] The side of the upper mold 1 that is opposite to the lower mold 2 is an arc surface;

[0087] The lower mold 2 includes a square base 201 and columns 202 disposed at the four corners of the base 201, with a groove 203 disposed on each column 202.

[0088] Specifically, the curvature of the arc surface of the upper mold 1 is the same as the arc curvature of the side plate.

[0089] For example, the length of the square base 201 is not less than the length of the symmetrical component, and the width of the square base 201 is not less than the width of the symmetrical component. The groove 203 is used to support the two ends of the two slabs in the symmetrical component; the height of each column 202 provides sufficient space when the symmetrical component bends downward.

[0090] When the symmetrical component is bent and formed using this side plate bending die, such as Figure 5 As shown, the symmetrical component is placed on the lower mold 2, and the two ends of the two blanks in the symmetrical component are placed in the corresponding grooves 203 respectively. The upper mold 1 is used to press down from the upper surface of the symmetrical component until the bending deformation of the symmetrical component is completed.

[0091] For example, in step 105, the method of splitting includes: splitting by gouging open the original weld position.

[0092] For example, in step 105, the method of processing the multi-step structure of each slab into the slope structure of the TF coil box side plate can be a machining method, for example, using a CNC machine tool to process to the part size requirements.

[0093] Specifically, step 2 includes:

[0094] Step 201: Forging the steel ingot;

[0095] Step 202: Forging a rectangular cross-section slab;

[0096] Step 203: Bend the rectangular cross-section blank to obtain the base plate of the arc-shaped component of the TF coil box.

[0097] For example, such as Figure 8 As shown, the forging in step 201 is similar to the forging in step 101, including at least one upsetting deformation and at least one drawing deformation. The forging ratio for upsetting deformation is not less than 1.7 (e.g., 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, etc.), and the final forging temperature is higher than 900℃ (e.g., 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, etc.). Before returning the forged billet to the furnace after upsetting deformation, the billet is wrapped with an asbestos anvil for heat preservation. After heat preservation, drawing deformation is performed using wide and flat anvils on both the top and bottom. The forging ratio for elongation deformation shall not be less than 1.7 (e.g., 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, etc.), and the final forging temperature shall be higher than 900℃ (e.g., 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, etc.). Before returning to the furnace, the forging billet shall be wrapped with an asbestos anvil for heat preservation.

[0098] For example, the bending forming process in step 203 is performed using a base plate bending die, such as... Figure 9 As shown.

[0099] Specifically, the base plate bending mold includes an upper mold 3 and a lower mold 4, and the side of the upper mold 3 opposite to the lower mold 4 is an arc surface;

[0100] The lower mold 4 includes a square base 401 and columns 402 disposed at the four corners of the base 401.

[0101] Specifically, the curvature of the arc surface of the upper mold 3 is the same as the arc curvature of the base plate.

[0102] For example, the length of the square base 401 is not greater than the length of the rectangular cross-section slab, and the width of the square base 401 is not less than the width of the rectangular cross-section slab. The height of each column 402 provides sufficient space for the rectangular cross-section slab to bend downwards.

[0103] When the rectangular cross-section slab is bent and formed using this base plate bending die, such as Figure 9 As shown, the rectangular cross-section slab is placed flat on the lower mold 4. The two ends of the rectangular cross-section slab are supported by the columns 402. The upper mold 3 is used to press down from the upper surface of the rectangular cross-section slab until the bending deformation of the rectangular cross-section slab is completed.

[0104] For example, before bending the symmetrical component in step 104 and bending the rectangular cross-section slab in step 203, the symmetrical component and the rectangular cross-section slab are first held at temperatures below the secondary recrystallization temperature. The holding time is determined to be one hour per 70-90 mm of the thickest section. Heating and holding at temperatures below the secondary recrystallization temperature can effectively avoid the problem of grain growth in austenitic stainless steel and further improve thermoplasticity.

[0105] For example, the secondary recrystallization temperature is 1000-1100℃.

[0106] For example, step 3 includes:

[0107] Step 301: Machining welding bevels on both sides of the base plate forging;

[0108] Step 302: Weld the two side plates and the base plate together according to the final position requirements to obtain the arc-shaped component of the TF coil box, as shown below. Figure 10 and Figure 11 .

[0109] The following specific embodiments further illustrate the preparation method of the arc-shaped component of the TF coil box of the present invention.

[0110] Example 1

[0111] This embodiment provides a method for manufacturing an arc-shaped component of a TF coil box. The arc-shaped component is made of N50 steel, the forging weighs approximately 4 tons, and it is manufactured using a 6-ton electroslag steel ingot. It includes:

[0112] Step 1: Make the side panels

[0113] 1. Pre-treat the electroslag ingot, and after annealing, process to remove the slag grooves on the surface of the electroslag ingot.

[0114] 2. The electroslag ingot undergoes homogenization heat treatment using a stepped heating method. The first temperature step is 840℃, the second is 1060℃, and the third is 1220℃. Each temperature step is held for one hour every 75 mm.

[0115] 3. For the initial forging of steel ingots, the steel ingots are first upset with an upsetting ratio of 1.8 and a final forging temperature of 1200℃. Before returning to the furnace, the forging billet is wrapped with an asbestos anvil. After heat preservation, the billet is drawn with upper and lower wide flat anvils with a drawing ratio of 1.8 and a final forging temperature higher than 1200℃. Before returning to the furnace, the forging billet is wrapped with an asbestos anvil.

[0116] 4. A pair of slabs are drawn out using an anvil. Each slab has a multi-step structure on one side and a flat surface on the other side. The multi-step structure is a gradually decreasing multi-step structure extending from one end of the slab to the other end, with a height difference of 50 mm between two adjacent steps. The forging ratio of each step in the multi-step structure is 1.4.

[0117] 5. Place the two slabs with multi-step structures face to face, and weld the steps corresponding to the largest cross sections of the two slabs together. The resulting assembly is a symmetrical assembly. Weld lifting lugs to both ends of the two slabs that make up the symmetrical assembly.

[0118] 6. The symmetrical component is held at a temperature below the secondary recrystallization temperature of 1065℃, with a holding temperature of 950℃. The holding time is determined by one hour for every 80mm of the thickest section. After the holding time, the symmetrical component is bent into shape using a side plate bending die. The symmetrical component is placed on the lower die, with the two ends of the two blanks in the symmetrical component placed in their respective grooves. The upper die is then used to press down from the upper surface of the symmetrical component until the bending deformation of the symmetrical component is completed.

[0119] 7. The steps corresponding to the maximum cross-sections of the two slabs are split, and then the multi-step structure of each slab is machined into a slope structure to obtain a pair of side plate forgings for the arc-shaped component of the TF coil box.

[0120] Step 2: Make the base plate

[0121] 1. Pre-treat the electroslag ingot, and after annealing, process to remove the slag grooves on the surface of the electroslag ingot.

[0122] 2. The electroslag ingot undergoes homogenization heat treatment using a stepped heating method. The first temperature step is 840℃, the second is 1060℃, and the third is 1220℃. Each temperature step is held for one hour every 75 mm.

[0123] 3. Forging of steel ingots: First, the steel ingot is upset with an upsetting ratio of 1.8 and a final forging temperature of 1200℃. Before returning it to the furnace, the forging billet is wrapped with an asbestos anvil. After heat treatment, it is drawn using upper and lower wide flat anvils with a drawing ratio of 1.8. The final forging temperature is higher than 1200℃. Before returning it to the furnace, the forging billet is wrapped with an asbestos anvil. Forging.

[0124] 4. A rectangular cross-section slab is drawn out using a flat anvil.

[0125] 5. The rectangular cross-section slab is held at a temperature below the secondary recrystallization temperature (1065℃) and a holding temperature of 950℃. The holding time is determined by one hour for every 80mm of the thickest section. After the holding time, the rectangular cross-section slab is bent into shape using a base plate bending die. The rectangular cross-section slab is placed on the lower die, with both ends placed on columns. The upper die is used to press down on the upper surface of the rectangular cross-section slab until the bending deformation is complete, resulting in the base plate of the arc-shaped component of the TF coil box.

[0126] Step 3: Weld the base plate to the pair of side plates.

[0127] 1. Welding bevels are machined on both sides of the base plate forging;

[0128] 2. Weld the two side plates and the base plate together according to the final position requirements to obtain the arc-shaped component of the TF coil box.

[0129] No bending instability occurred during the bending deformation process in this embodiment; the grain size in the microstructure of the forging was grade 4-5, and the grains were fine and uniform. Figure 15 As shown; forging accuracy refers to the machining allowance from the forging blank to the final structural part, and the machining allowance of each part is less than 20mm.

[0130] Example 2

[0131] This embodiment provides a method for preparing an arc-shaped component of a TF coil box similar to that in Embodiment 1. The difference is that the homogenization heat treatment is not a stepped heating method, but a direct heating to 1220°C.

[0132] The microstructure of the forgings obtained in this embodiment has a grain size of 1-3, with a small amount of mixed grains and coarse grains, and the machining allowance for each part is 30-40 mm.

[0133] Example 3

[0134] This embodiment provides a method for preparing the arc-shaped component of the TF coil box similar to that of Embodiment 1, except that the final forging temperature for upsetting and drawing is 700°C.

[0135] The forging obtained in this embodiment has a small number of cracks on its surface.

[0136] Example 4

[0137] This embodiment provides a method for preparing an arc-shaped component of a TF coil box similar to that of Embodiment 1, except that the surface slag grooves of the electroslag ingot are not removed before the homogenization heat treatment.

[0138] The forging obtained in this embodiment has a small number of cracks on its surface.

[0139] Example 5

[0140] This embodiment provides a method for preparing an arc-shaped component of a TF coil box similar to that of Embodiment 1. The difference is that, before bending the symmetrical component, the symmetrical component is kept at a temperature exceeding the secondary recrystallization temperature (1150°C).

[0141] The microstructure of the forging obtained in this embodiment has a grain size of 1-3.

[0142] Comparative Example 1

[0143] This comparative example provides a method for preparing an arc-shaped component of a TF coil box similar to that in Example 1. The difference is that the preparation process of the side plate includes: first preparing a rectangular steel ingot, then bending the steel ingot to form an arc shape, then forging the bent steel ingot into a variable cross-section asymmetric structure of the target part, the forged blank finished product is a simple shape structure, and finally removing the excess blank by machining.

[0144] The microstructure of the forging prepared in this comparative example has a grain size of grade 1-2, and the machining allowance for each part of the side plate is 20-300 mm.

[0145] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an arc-shaped component of a TF coil box, characterized in that, The preparation method includes: Step 1: Make the side panels, including: Step 101: Forging the steel ingot; Step 102: Slab forging, forging a pair of slabs, each slab having a multi-step structure on one side and a flat surface on the other side; Step 103: Place the two slabs with multi-step structures face to face, and weld the steps corresponding to the largest cross sections of the two slabs together. The assembled component is a symmetrical component. Step 104: Press down from the upper surface of the symmetrical component until the bending deformation of the symmetrical component is completed; The bending and forming process in step 104 is carried out using a side plate bending die; The side plate bending mold includes an upper mold and a lower mold, and the side of the upper mold opposite to the lower mold is an arc surface; The lower mold includes a square base and columns disposed at the four corners of the base, with a groove provided on each column; When bending the symmetrical component using the side plate bending die, the symmetrical component is placed on the lower die, and the two ends of the two blanks in the symmetrical component are placed in the corresponding grooves. The upper die is used to press down from the upper surface of the symmetrical component until the bending deformation of the symmetrical component is completed. Step 105: Divide the steps corresponding to the maximum cross-section of the two slabs, and then process the multi-step structure of each slab into the slope structure of the TF coil box side plate to obtain a pair of TF coil box side plates. Step 2: Make the base plate; Step 3: Weld the base plate to a pair of side plates.

2. The preparation method according to claim 1, characterized in that, The multi-step structure is a multi-step structure that extends from one end of the slab to the other end and the step height gradually decreases.

3. The preparation method according to claim 2, characterized in that, In the multi-step structure, the height difference between two adjacent steps is 45-55mm.

4. The preparation method according to claim 1, characterized in that, In step 102, the forging ratio of each step in the multi-step structure is not less than 1.

3.

5. The preparation method according to claim 1, characterized in that, Step 2 includes: Step 201: Forging the steel ingot; Step 202: Forging a rectangular cross-section slab; Step 203: Bend the rectangular cross-section blank to obtain the base plate of the arc-shaped component of the TF coil box.

6. The preparation method according to claim 5, characterized in that, The bending and forming process in step 203 is carried out using a base plate bending die; The base plate bending mold includes an upper mold and a lower mold, and the side of the upper mold opposite to the lower mold is an arc surface; The lower mold includes a square base and columns located at the four corners of the base.

7. The preparation method according to claim 5, characterized in that, In steps 101 and 201, before forging the steel ingot, the steel ingot is first subjected to a homogenization heat treatment.

8. The preparation method according to claim 7, characterized in that, The homogenization heat treatment adopts a stepped heating method, including: a first temperature step of 840-860℃, a second temperature step of 1050-1060℃, and a third temperature step of 1200-1220℃.

9. The preparation method according to claim 5, characterized in that, Before bending the symmetrical component in step 104 and bending the rectangular cross-section slab in step 203, the symmetrical component and the rectangular cross-section slab are kept at a temperature below the secondary recrystallization temperature.

Images