Integrated head punching plate blank near-net forming aid, integrated head, and method of manufacturing the same

Abstract

The application relates to an integrated head punching plate blank near-net forming auxiliary tool, an integrated head and a preparation method thereof, and belongs to the field of head manufacturing. At least one of the problems in the prior art, such as great demolding difficulty, long production cycle, low material utilization rate and difficult forming of a complex structure, is solved. The integrated head punching plate blank near-net forming auxiliary tool comprises a top block assembly and a lower die. The top block assembly comprises a top block area, a top block sink cavity area and a spring. The lower die comprises a hollow area and a lower die sink cavity area. The near-net forming auxiliary tool and the manufacturing method provided by the application significantly reduce the demolding difficulty, shorten the production cycle, reduce the machining allowance, improve the material utilization rate, and realize efficient, high-quality and low-cost manufacturing of integrated large heads, especially integrated large heads with complex structures.

Description

Technical Field

[0001] This invention relates to the field of end cap manufacturing technology, and in particular to near-net-shape forming fixtures for slabs used in stamping integrated end caps, integrated end caps, and their preparation methods. Background Technology

[0002] As my country's energy, chemical, aerospace, and marine engineering industries drive the development of industrial equipment towards integration and large-scale production, the heads of large containers (such as pressure vessels in nuclear power plants, evaporators, and large chemical containers) are also showing this trend. To improve stability, these heads adopt integrated complex structures. The manufacturing process typically involves first machining a blank for stamping, and then stamping it into shape. Among these steps, blank manufacturing is the longest and most difficult. Traditional free forging followed by machining methods suffer from long cycles, low material utilization, and difficulties in forming complex structures. While the die forging technology adopted in recent years can be used to manufacture blanks for stamping, it generally presents challenges such as difficult demolding, especially when manufacturing large integrated heads with multiple nozzles of different specifications. Summary of the Invention

[0003] Based on the above analysis, the present invention aims to provide a near-net-shape forming tool for slab blanks for stamping integrated heads, an integrated head and its preparation method, in order to solve at least one of the problems in the prior art of manufacturing integrated heads, especially large integrated heads with nozzles of different specifications, such as high demolding difficulty, long production cycle, low material utilization rate and difficulty in forming complex structures.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] This invention provides an integrated near-net-shape forming fixture for end cap punching, the near-net-shape forming fixture comprising: a top block assembly and a lower die;

[0006] The top block assembly includes a top block region, a top block recessed cavity region, and a spring; wherein...

[0007] The top block assembly has a central protrusion that forms a top block area;

[0008] The top block recessed cavity region is arranged around the top block region and sinks in a stepped manner. The top block recessed cavity region includes, from the outside to the inside in the radial direction, the following:

[0009] The first sunken cavity is arranged in a ring shape;

[0010] The second sinking cavity is distributed in a ring shape, and the bottom surface of the second sinking cavity extends to the root of the top block area and then terminates.

[0011] The first step surface is located between the first sinking cavity and the second sinking cavity, forming a rigid limiting surface when the lower mold moves downward;

[0012] The spring is disposed in the second recessed cavity, and the top end of the spring abuts against the bottom surface of the lower mold and is compressed when the mold is closed;

[0013] The lower mold includes a hollow area and a recessed cavity area; wherein...

[0014] The hollowed-out area is located in the middle of the lower mold and is used to accommodate the top block area;

[0015] The lower mold recessed cavity area is arranged around the hollowed-out area and sinks in a stepped manner. The lower mold recessed cavity area includes, from the outside to the inside, the following in a radial direction:

[0016] A third sunken cavity with a ring-shaped distribution;

[0017] A fourth recessed cavity is arranged in a ring shape, and the bottom surface of the fourth recessed cavity extends to the boundary of the hollowed-out area and then terminates.

[0018] The second step surface is located between the third and fourth sinking cavities.

[0019] Furthermore, the integral head forming blank to be formed includes a first protrusion located in the middle of the blank, and a second protrusion distributed in a ring around the first protrusion.

[0020] Furthermore, the top block region includes an upper annular boss structure and a lower column structure, wherein,

[0021] The annular boss structure has an open inner cavity, and the inner peripheral wall of the open inner cavity and the outer peripheral wall of the annular boss structure are respectively conforming to the outer peripheral wall of the first protrusion and the inner peripheral wall of the second protrusion of the blank to be formed.

[0022] The outer peripheral wall of the column structure is adapted to the shape of the inner peripheral wall of the hollow area of ​​the lower mold and slides in fit.

[0023] Furthermore, the second protrusion of the blank to be formed is provided with multiple bulges in the circumferential direction, and each bulge has a radially concentric bulging section and a centrifugal bulging section at the same time;

[0024] The outer peripheral wall of the annular protrusion structure in the top block area is provided with multiple concave sections. The number, circumferential position and concave contour of the concave sections correspond one-to-one with the concave bulge sections of each bulge and follow their shape.

[0025] The inner circumferential wall of the fourth sinking cavity is provided with multiple centrifugal concave sections. The number, circumferential position and concave contour of the centrifugal concave sections correspond one-to-one with the centrifugal outer bulge sections of each bulge and follow their shape.

[0026] Furthermore, the contour dimension defined by the inner peripheral wall of the first sinking cavity is not less than the contour dimension defined by the outer peripheral wall of the lower mold, and the contour dimension defined by the outer peripheral wall of the lower mold is greater than the contour dimension defined by the inner peripheral wall of the second sinking cavity.

[0027] Furthermore, the inner peripheral wall of the third recessed cavity conforms to the outer peripheral wall of the slab to be formed; and / or,

[0028] The inner peripheral wall of the fourth recessed cavity conforms to the outer peripheral wall of the second protrusion of the slab to be formed.

[0029] Furthermore, the near-net-shape forming tool also includes: an edge-opening hammer, the two ends of which conform to the outer peripheral wall of the lower mold.

[0030] This invention provides a method for preparing an integrated head, which involves forming a blank using the aforementioned near-net-shape forming fixture, and then punching and enveloping the blank to obtain an integrated head; the method for forming the blank using the aforementioned near-net-shape forming fixture includes the following steps:

[0031] (a) In-mold upsetting:

[0032] Assemble the top block assembly of the near-net-shape forming tooling with the lower mold;

[0033] The initial blank is placed in the lower mold, and the press is driven to make the lower mold and the top block assembly move relative to each other. The lower mold moves and compresses the spring. During the mold closing process, the blank is plastically flowed through upsetting in the mold to form the required structure of the intermediate blank.

[0034] When the lower die reaches contact with the first step surface of the top block assembly, the upsetting process is completed;

[0035] During the press return stroke, the spring releases its elastic force to push the lower die and the intermediate blank formed in the die after upsetting away from the top block assembly, thereby realizing the demolding of the top block area of ​​the top block assembly from the intermediate blank;

[0036] (b) In-mold edge opening forming: After the in-mold upsetting is completed, the intermediate blank located in the lower mold is rotated and edge-opened so that the outer diameter of the intermediate blank is expanded to the size that matches the inner peripheral wall of the third recessed cavity of the lower mold, thus obtaining a slab blank.

[0037] Furthermore, in the rotating edge opening process, the amount of pressure applied by each hammer is controlled between 50mm and 100mm, and the rotation angle is controlled uniformly at 20°-30° per hammer.

[0038] The present invention provides an integrated end cap, which is formed by punching and enveloping a blank made of the near-net-shape forming tool; or by the preparation method described above.

[0039] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0040] (1) This invention addresses the common problem of demolding difficulties in the existing technology of forming integrated head blanks using die forging. Through innovative mold structure design, a near-net-shape forming tooling suitable for integrated head blanks is designed, effectively solving this problem. In existing molds, when forming large multi-nozzle head blanks, the punch structure is prone to engaging with the blank, resulting in high demolding resistance, low efficiency, and easy damage to the blank surface. Compared to traditional die forging molds used for forming integrated head blanks, this invention, through the coordinated design of the top block assembly and the lower die cavity, and the built-in spring mechanism in the cavity, cleverly uses spring force to automatically and quickly separate the lower die along with the intermediate blank obtained from the upsetting from the top block assembly after in-mold upsetting. This solution has a simple structure, is easy to operate, significantly reduces demolding difficulty, and avoids product defects that may be caused by forced demolding. Therefore, this invention enables the forging process to be reliably used for near-net-shape forming of such complex slabs, significantly shortening the production cycle and reducing machining allowances while reducing the overall manufacturing difficulty, thus achieving efficient, high-quality, and low-cost manufacturing of integrated large heads, especially integrated large heads with complex structures.

[0041] (2) Compared to the traditional method of manufacturing stamped head blanks using free forging followed by machining, the near-net-shape forming fixture disclosed in this invention achieves near-net-shape forming of the head blank through the coordinated design of the top block assembly and the lower mold cavity, and by setting a spring mechanism within the cavity. This invention significantly shortens the production cycle and reduces machining allowance while ensuring that the blank quality is comparable to or even better than traditional processes, thereby improving material utilization and reducing costs. Through the structural innovation of the fixture, this invention effectively improves the dimensional accuracy and quality consistency of stamped head blanks, reduces the difficulty of process control, and overcomes the defects of traditional free forging + machining manufacturing of stamped head blanks, such as unstable dimensional control, large machining allowance / low material utilization, and poor forming consistency.

[0042] (3) In some preferred embodiments, the fixture of the present invention decomposes the forming surfaces of complex protrusions and bulges on the slab blank for forming the integrated head into corresponding cavities of the top block assembly and the lower die, and ensures that the number, position and contour of each cavity conform to the product features, thereby achieving near-net-shape forming of complex structures with simple axial opening and closing action. The fixture design, through complementary surfaces and built-in elastic structure, effectively solves the demolding problem while avoiding lateral core pulling mechanisms, significantly improving the reliability, life and forming efficiency of the mold, and is especially suitable for complex components such as integrated heads. It has the advantages of low manufacturing cost and difficulty as well as high process efficiency while ensuring product quality and forming accuracy.

[0043] (4) The integrated head manufacturing method provided by this invention achieves three key technical effects through its designed near-net-shape forming auxiliary tooling: First, by utilizing the precise cooperation between the top block assembly and the lower die, the complex protruding structure required for stamping slabs can be precisely formed through a single axial die closing, significantly improving forming efficiency and quality consistency; second, the spring mechanism can cleverly achieve automatic and rapid demolding when the press is lifted, effectively solving the long-standing demolding problem and blank damage problem; third, by using the edge-opening hammer to rotate and open the blank, the outer contour can be processed efficiently without affecting the already formed structure. Overall, this method has significant advantages in reducing manufacturing difficulty, improving forming efficiency, ensuring product quality, and improving material utilization.

[0044] 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

[0045] 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.

[0046] Figure 1 (a) is a structural schematic diagram of the top block assembly of the near-net-shape forming fixture provided in an embodiment of the present invention, (b) is a top view of the top block assembly, and (a) is a schematic diagram of the top block assembly. Figure 1 (b) sectional view of section AA, (c) three-dimensional view of the top block assembly;

[0047] Figure 2 for Figure 1 (a) Enlarged schematic diagram;

[0048] Figure 3 (a) is a schematic diagram of the lower mold of the near-net-shape forming tooling provided in an embodiment of the present invention, (b) is a top view of the lower mold, and (a) is... Figure 3 (b) A cross-sectional view of section AA in the middle, and (c) A three-dimensional view of the lower mold;

[0049] Figure 4 for Figure 3 (a) Enlarged schematic diagram;

[0050] Figure 5 This is a schematic diagram of the top block assembly and the lower mold after mold closing of the near-net-shape forming tooling provided in an embodiment of the present invention (the spring is not placed in the recessed cavity);

[0051] Figure 6The diagram shows the top block assembly and the lower mold after mold closing of the near-net-shape forming tool provided in the embodiment of the present invention (the spring is placed in the recessed cavity). (a) is a cross-sectional view and (b) is a perspective view.

[0052] Figure 7 (a) is a schematic diagram of the edge-opening hammer head of the near-net-shape forming tooling provided in the embodiments of the present invention, (b) is a top view of the edge-opening hammer head, and (a) is... Figure 7 (b) Schematic sectional view of section AA;

[0053] Figure 8 The diagram shows the in-mold upsetting process in the manufacturing method of the integrated head provided in the embodiment of the present invention. (a) is before mold closing, (b) after in-mold upsetting is completed, and (c) after demolding.

[0054] Figure 9 The diagram shows the in-mold edge opening forming process in the manufacturing method of the integrated end cap provided in the embodiment of the present invention. (a) is before rotating the edge opening, (b) is after the in-mold edge opening forming is completed, and (c) is after demolding.

[0055] Figure 10 The following are schematic diagrams of the intermediate blank and the slab blank for forming the integrated head obtained by the integrated head manufacturing method provided in the embodiments of the present invention: (a) is a cross-sectional view of the intermediate blank, (b) is a three-dimensional view of the intermediate blank, (c) is a cross-sectional view of the slab blank for forming the integrated head, and (d) is a three-dimensional view of the slab blank for forming the integrated head.

[0056] Figure 11 (a) is a schematic diagram of an integrated head obtained by using the near-net-shape forming fixture or integrated head manufacturing method provided in the embodiments of the present invention. (b) is a top view of the integrated head. (a) is a schematic diagram of an integrated head obtained by using the near-net-shape forming fixture or integrated head manufacturing method provided in the embodiments of the present invention. Figure 11 (b) Schematic sectional view of section AA;

[0057] Figure 12 The image shows a photograph of an integrated head obtained using the near-net-shape forming fixture or integrated head manufacturing method provided in the embodiments of the present invention.

[0058] Figure label:

[0059] 10-Slab to be formed, 10a-Outer peripheral wall of slab, 11-First protrusion of slab, 11a-Outer peripheral wall of the first protrusion in slab, 12-Second protrusion of slab, 121-Bulge on the second protrusion, 121A-Centripetal bulging section, 121B-Centrifugal bulging section, 12a-Inner peripheral wall of the second protrusion in slab, 12b-Outer peripheral wall of the second protrusion in slab; 20-Top block assembly, 20a-Outer peripheral wall of the top block assembly, 21-Top block area, 211-Annular boss structure, 211a-Open inner cavity, 211a-Inner peripheral wall of the open inner cavity, 211b-Outer peripheral wall of the annular boss structure, 211b-1: Centripetal concave section provided on the outer peripheral wall of the annular boss structure, 212-Columnar structure, 212b-Outer peripheral wall of the columnar structure, 22-Top block recessed cavity area, 22a-First recessed cavity 22a1 - Inner peripheral wall of the first recessed cavity, 22b - First step surface, 22c - Second recessed cavity, 22c1 - Inner peripheral wall of the second recessed cavity, 23 - Spring, 30 - Lower mold, 30a - Outer peripheral wall of the lower mold, 31 - Hollowed-out area, 31a - Inner peripheral wall of the hollowed-out area, 32 - Lower mold recessed cavity area, 32a - Third recessed cavity, 32a1 - Inner peripheral wall of the third recessed cavity, 32b - Second step surface, 3 2c-Fourth sinking cavity, 32c1-Inner peripheral wall of the fourth sinking cavity, 32c1-1: Centrifugal concave section provided on the inner peripheral wall of the fourth sinking cavity, 40-Opening hammer, 40a-End of the opening hammer, 50-Initial billet, 60-Intermediate billet, 70-Rotating platform, 90-Unloading platform, 00-Integrated end cap, 01-First end cap nozzle, 02-Second end cap nozzle, 03-End cap manhole. Detailed Implementation

[0060] 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.

[0061] To address the aforementioned shortcomings in existing technologies, this invention proposes the following technical solutions by focusing on both mold structure innovation and manufacturing process optimization:

[0062] In a first aspect, the present invention provides an integrated near-net-shape forming fixture for end cap punching, the near-net-shape forming fixture comprising: a top block assembly 20 and a lower die 30;

[0063] The top block assembly 20 includes a top block region 21, a top block recessed cavity region 22, and a spring 23, wherein...

[0064] The top block assembly 20 has a central protrusion that forms the top block region 21;

[0065] The top block recessed cavity region 22 is arranged around the top block region 21 and sinks in a stepped manner. The top block recessed cavity region 22 includes, from the outside to the inside in the radial direction, the following:

[0066] The first sinking cavity 22a is distributed in a ring shape.

[0067] The second recessed cavity 22c is arranged in a ring shape, and its bottom surface extends to the root of the top block area 21 and then terminates.

[0068] The first step surface 22b is located between the first sinking cavity 22a and the second sinking cavity 22c, forming a rigid limiting surface when the lower mold 30 moves downward;

[0069] The spring 23 is disposed in the second recessed cavity 22c, and the top end of the spring 23 abuts against the bottom surface of the lower mold 30 and is compressed when the mold is closed;

[0070] The lower mold 30 includes a hollow area 31 and a lower mold recessed cavity area 32, wherein,

[0071] The hollow area 31 is located in the middle of the lower mold 30 and is used to accommodate the top block area 21;

[0072] The lower mold recessed cavity area 32 is arranged around the hollowed-out area 31 and sinks in a stepped manner. The lower mold recessed cavity area 32 includes, from the outside to the inside in the radial direction:

[0073] The third sunken cavity 32a is arranged in a ring shape;

[0074] The fourth recessed cavity 32c is distributed in a ring shape, and the bottom surface of the fourth recessed cavity 32c extends to the boundary of the hollow area 31 and then terminates.

[0075] The second step surface 32b is located between the third sinking cavity 32a and the fourth sinking cavity 32c.

[0076] It can be understood that the hollowed-out area 31 is a through-hole structure.

[0077] This invention addresses the common problem of difficult demolding in existing forging processes for forming integrated head blanks. Through an innovative mold structure design, it effectively solves this problem. Existing molds, when forming large multi-nozzle head blanks, often result in the punch structure engaging with the blank, leading to high demolding resistance, low efficiency, and potential damage to the blank surface. Compared to traditional forging molds for forming integrated head blanks, this invention utilizes a collaborative design between the top block assembly and the lower die cavity, incorporating a built-in spring mechanism. After in-mold upsetting, the spring force cleverly and quickly separates the lower die, along with the intermediate blank obtained from the upsetting, from the top block assembly. This solution is simple in structure and easy to operate, significantly reducing demolding difficulty and avoiding product defects that may result from forced demolding. Therefore, this invention enables reliable forging processes for near-net-shape forming of such complex blanks, significantly shortening the production cycle, reducing machining allowances, and lowering overall manufacturing difficulty. It provides a reliable technical solution for the efficient, high-quality, and low-cost manufacturing of integrated large heads.

[0078] Compared to the traditional method of manufacturing stamped head blanks using free forging followed by machining, the near-net-shape forming fixture disclosed in this invention achieves near-net-shape forming of the head blank through the coordinated design of the top block assembly and the lower mold cavity, and by incorporating a spring mechanism within the cavity. This invention significantly shortens the production cycle and reduces machining allowance while ensuring blank quality comparable to or even better than traditional processes, thereby improving material utilization and reducing costs. Through the structural innovation of the fixture, this invention effectively improves the dimensional accuracy and quality consistency of stamped head blanks, reduces process control difficulty, and overcomes the defects of traditional free forging + machining manufacturing of stamped head blanks, such as unstable dimensional control, large machining allowance / low material utilization, and poor forming consistency.

[0079] In one embodiment, the integral end cap forming blank 10 to be formed includes a first protrusion 11 located in the middle of the blank 10, and a second protrusion 12 distributed in a ring around the first protrusion 11.

[0080] Specifically, the second protrusion 12 and the first protrusion 11 are radially spaced.

[0081] Specifically, the second protrusion 12 in the blank 10 to be formed has a plurality of bulges 121 in the circumferential direction, and each bulge 121 has a radially concentric outer bulge section 121A and a centrifugal outer bulge section 121B.

[0082] Optionally, the outer peripheral wall contour of the slab 10 to be formed can be a regular shape or an irregular shape. For example, the outer peripheral wall contour of the slab 10 can be a centrally symmetrical shape, such as a circle or an ellipse.

[0083] It can be understood that the "centripetal bulging section 121A" refers to the section that bulges outward toward the central area of ​​the slab, and the "centrifugal bulging section 121B" refers to the section that bulges outward away from the central area of ​​the slab. When the outer peripheral wall contour of the slab 10 is a centrally symmetrical figure, the central area is specifically the center of the centrally symmetrical figure.

[0084] Preferably, the plurality of bulges 121 are arranged symmetrically in pairs about the center of the slab 10. Specifically, the bulges 121 are manhole seats used for forming manholes during slab stamping. By setting the manhole seats in pairs symmetrically arranged, it is ensured that the load does not become eccentric during the slab stamping process, thereby ensuring the machining accuracy and product yield of the manhole in the final integrated head. See also Figure 10 and Figure 11 The integrated end cap 00 includes multiple end cap nozzles 01 and 02 and an end cap manhole 03. Correspondingly, a pair of bulges 121 are symmetrically arranged on the second protrusion 12 of the preformed or unformed slab 10 about the center of the slab 10. The bulges 121 can also be called manhole seats, which are used to ensure uniform load distribution and avoid uneven load during the punching process.

[0085] More preferably, the plurality of bulges 121 are distributed at equal angular intervals around the second protrusion 12 in the circumferential direction of the blank 10. Exemplarily, the plurality of bulges 121 have the same shape.

[0086] For example, the first protrusion 11 is located in the central region of the slab 10 and is shaped as a protruding cylinder.

[0087] For example, the first protrusion 11 and the second protrusion 12 are arranged coaxially about the central axis of the blank 10 to be formed.

[0088] For example, the second protrusion 12 is an annular protrusion distributed around the first protrusion 11. On the second protrusion 12, the non-bulging area has a uniform thickness, and the centripetal outward bulging section 121A and centrifugal outward bulging section 121B of each bulge 121 are symmetrical arcs. Specifically, the centripetal outward bulging section 121A and centrifugal outward bulging section 121B of each bulge 121 are symmetrical about the central axis of the bulge 121, which is located on the middle ring of the annular protrusion. It can be understood that the middle ring is the ring exactly between the inner and outer rings of the annular protrusion.

[0089] In one embodiment, the top block region 21 includes an upper annular boss structure 211 and a lower column structure 212, wherein,

[0090] The annular boss structure 211 has an open inner cavity 211a. The inner peripheral wall 211a-1 of the open inner cavity 211a and the outer peripheral wall 211b of the annular boss structure 211 are respectively conforming to the outer peripheral wall 11a of the first protrusion 11 and the inner peripheral wall 12a of the second protrusion 12 of the blank 10 to be formed.

[0091] The outer peripheral wall 212b of the column structure 212 is adapted to the shape of the inner peripheral wall 31a of the hollow area 31 of the lower mold 30 and slides in fit.

[0092] For example, the outer peripheral wall of the annular boss structure 211 has a draft angle (e.g., 1 to 7 degrees), and the radial dimension of the outer peripheral wall of the annular boss structure decreases monotonically along the demolding direction to form a conical outer wall with a small top and a large bottom, which is conducive to demolding. The maximum dimension of the bottom of the annular boss structure 211 (the end closest to the column structure 212) is not greater than the outline dimension of the outer peripheral wall of the column structure 212.

[0093] For example, the column structure 212 is a cylinder.

[0094] For example, the height 2H3 of the column structure 212 is greater than the depth 2H2 of the second recessed cavity 22c, and the portion of the column structure 212 that extends beyond the height of the second recessed cavity 22c (2H3-2H2) is adapted to the shape of the inner peripheral wall 31a of the hollow area 31 of the lower mold 30 and can achieve a sliding fit.

[0095] For example, see Figures 1-6 The column structure 212 is a cylinder with a diameter of 2D2. The hollow area 31 is a cylindrical hollow structure with a diameter of 3D3. The above dimensions satisfy the following relationship: 3D3-2D2=δ, where δ is the sliding fit clearance in the mechanical field. For example, the value of δ ranges from 0.0015 inches to 0.0040 inches, and for high-precision fits, 0.0001 inches≤δ≤0.0020 inches.

[0096] For example, the top block region 21 and the top block recessed cavity region 22 are coaxially arranged on the central axis of the top block assembly 20. Specifically, the first recessed cavity 22a and the second recessed cavity 22c included in the top block recessed cavity region 22 are coaxially arranged on the central axis of the top block assembly 20. It can be understood that the top block assembly 20 is a coaxially combined rotating body with a central axis.

[0097] For example, the inner peripheral walls of the third recessed cavity 32a and / or the fourth recessed cavity 32c and / or the open inner cavity 211a extend from the opening end toward the bottom wall and have draft angles, such as draft angles of 1° to 7°. The radial dimensions of the inner peripheral walls of the third recessed cavity 32a and / or the fourth recessed cavity 32c and / or the open inner cavity 211a increase monotonically along the demolding direction to form a conical cavity with a large opening and a small bottom, which is conducive to demolding.

[0098] For example, the inner peripheral walls of the first recessed cavity 22a and / or the second recessed cavity 22c are parallel to the central axis of the top block assembly 20. The first stepped surface 22b is perpendicular to the central axis of the top block assembly 20.

[0099] For example, the bottom of the open inner cavity 211a conforms to the top surface of the first protrusion 11 in the blank 10 to be formed (the complete surface of the first protrusion 11 that is furthest from the base of the blank 10).

[0100] The spring 23 is disposed within the second recessed cavity 22c, and the top end of the spring 23 abuts against the bottom surface of the lower mold 30 during mold closing. The spring 23 is configured to provide flexible floating support during mold closing and drive the lower mold 30 and intermediate blank to reset during demolding, thereby achieving rapid and non-destructive demolding.

[0101] Preferably, there are multiple springs 23, which are evenly distributed within the second sinking cavity 22c.

[0102] In one embodiment, the hollow area 31 and the lower mold cavity area 32 are coaxially arranged on the central axis of the lower mold 30. Specifically, the lower mold cavity area 32 includes a third recessed cavity 32a and a fourth recessed cavity 32c, which are coaxially arranged on the central axis of the lower mold 30. It can be understood that the lower mold 30 is a coaxially combined rotating body with a central axis.

[0103] For example, the inner peripheral wall 32a1 of the third recessed cavity 32a conforms to the outer peripheral wall 10a of the blank 10 to be formed.

[0104] For example, the inner peripheral wall 32c1 of the fourth recessed cavity 32c conforms to the outer peripheral wall 12b of the second protrusion 12 in the blank 10 to be formed.

[0105] For example, the second step surface 22b conforms to the region (such as an annular region) between the root of the second protrusion 12 and the outer peripheral wall 10a of the slab 10 to be formed.

[0106] For example, the bottom of the fourth recessed cavity 32c conforms to the top surface of the second protrusion 12 in the blank 10 to be formed (the complete surface of the second protrusion 12 itself that is furthest from the blank 10 base).

[0107] Furthermore, the present invention uses the top block assembly 20 and the cavity of the lower mold 30 to jointly form each bulge 121 of the second protrusion 12 on the blank 10.

[0108] Specifically, the outer peripheral wall 211b of the annular boss structure 211 of the top block area 21 is provided with a plurality of concentric concave sections 211b-1. The number, circumferential position and concave contour of the concentric concave sections 211b-1 correspond one-to-one with the concentric bulging sections 121A of each bulge 121 and follow the shape.

[0109] The inner peripheral wall 32c1 of the fourth sinking cavity 32c is provided with a plurality of centrifugal concave sections 32c1-1. The number, circumferential position and concave surface contour of the centrifugal concave sections 32c1-1 correspond one-to-one with the centrifugal outer bulge section 121B of each bulge 121 and follow its shape.

[0110] It should be noted that the ingenuity of the auxiliary tooling design in this invention lies in the clever decomposition of the complex first protrusion and the second protrusion containing multiple bulges on the blank to be formed into a top block area and a stepped-down top block cavity area on the top block assembly, and a hollow area and a stepped-down lower mold cavity area on the lower mold. By utilizing the centripetal concave section of the top block area in the top block assembly, the centrifugal concave section on the lower mold, and the stepped multi-level sinking cavity and the open cavity of the top block area, the cavities of the two mold components together form a complete protrusion and bulge forming space after mold closing. The cavities of the mold components and each concave section strictly conform to the corresponding sections of the target feature in terms of quantity, circumferential position, and surface contour, thereby achieving near-net-shape forming of complex three-dimensional features with simple axial mold opening and closing actions. This solution not only effectively solves the demolding problem of multi-protrusion and multi-bulge structures through complementary surface decomposition and clever setting of elastic structure, but also significantly improves the reliability and service life of mold operation by avoiding the use of complex mechanisms such as side core pulling. While ensuring forming accuracy, it reduces manufacturing difficulty and maintenance costs and improves forming efficiency. Especially for complex integrated end caps, this invention shows significant advantages of reduced manufacturing difficulty, reduced costs and improved efficiency while ensuring product quality.

[0111] Specifically, the inner peripheral wall of the outermost recessed cavity (first recessed cavity 22a) in the top block recessed cavity area 22 along the radial direction can accommodate the outer peripheral wall of the lower mold 30, and when the mold is closed, the bottom of the lower mold 30 abuts against the bottom of the outermost recessed cavity (first recessed cavity 22a) in the top block recessed cavity area 22 along the radial direction.

[0112] Specifically, the contour dimension defined by the inner peripheral wall 22a1 of the first recessed cavity 22a is not less than the contour dimension defined by the outer peripheral wall 30a of the lower mold 30; and the contour dimension defined by the outer peripheral wall 30a of the lower mold 30 is greater than the contour dimension defined by the inner peripheral wall 22c1 of the second recessed cavity 22c. This dimensional design provides guidance and motion tolerance for the downward movement of the lower mold, ensuring its smooth introduction into the top block assembly. Based on this, after the lower mold smoothly enters the first recessed cavity 22a, it continues to descend and compress the spring 23. This process causes the blank to be gradually pushed out (reverse extrusion) on the top block area 21, thereby sequentially forming the first protrusion 11. The compression of the spring 23 provides the necessary flexible pressure to ensure sufficient material filling. When the lower mold 30 descends to its final position (such as the first step surface 22b limit), the inner peripheral wall of the fourth recessed area 32c on the lower mold 30 and the outer peripheral wall of the top block area 21 work together to precisely form the second protrusion 12, thereby completing the synchronous precision forming of complex features through axial movement. See also Figures 1-6 When the outline defined by the inner peripheral wall 22a1 of the first recessed cavity 22a is circular, its diameter is 2D1. When the outline defined by the inner peripheral wall 22c1 of the second recessed cavity 22c is circular, its diameter is 2D3. The outline defined by the outer peripheral wall 30a of the lower mold 30 is circular, its diameter is 3D1. The above diameters satisfy the following relationship: 2D1 ≥ 3D1 > 2D3.

[0113] Specifically, the depth of the open cavity 211a of the annular boss structure 211 in the upper part of the top block area 21 is equal to the depth of the fourth recessed cavity 32c of the lower die 30; this ensures that the first protrusion 11 and the second protrusion 12 in the formed slab have the same height (vertical distance from the root to the top of the protrusion), which is beneficial for a more reasonable stress distribution during subsequent slab forming and service, reducing stress concentration caused by sudden changes in thickness, and improving product fatigue life. See also Figures 1-6 When the bottom of the open inner cavity 211a is a plane, the depth of the open inner cavity 211a of the annular boss structure 211 on the top block area 21 is 2H4. When the bottom surface of the fourth recessed cavity 32c is a plane, the depth of the fourth recessed cavity 32c of the lower mold 30 is 3H2. When the tops of the first protrusion 11 and the second protrusion 12 of the blank 10 to be formed are flush and the height of both is 1H2; the above dimensions satisfy the following relationship: 2H4=3H2=1H2.

[0114] Specifically, the difference between the height of the column structure 212 at the lower part of the top block area 21 and the depth of the second recessed cavity 22c is equal to the depth of the hollow area 31. See also Figures 1-6When the bottom of the second recessed cavity 22c is a plane, the height of the column structure 212 at the bottom of the top block area 21 (relative to the bottom plane of the second recessed cavity 22c) is 2H3, and the depth of the second recessed cavity 22c (relative to the bottom plane of the second recessed cavity 22c) is 2H2. The depth of the hollow area 31 is 3H3; the above dimensions satisfy the following relationship: 3H3 = 2H3 - 2H2, so as to ensure that when the bottom of the lower mold 30 abuts against the first step surface 22b, the bottom of the fourth recessed cavity 32c of the lower mold 30 is flush with the root of the annular boss structure 211, together forming the top surface of the second protrusion 12 on the blank 10.

[0115] It can be understood that "the depth of the hollow area 31" refers to the vertical distance from the top surface of the hollow area 31 (e.g., the surface that is level with the fourth recessed cavity 32c in the lower mold) to the bottom surface of the hollow area (e.g., the surface that is level with the bottom of the lower mold).

[0116] Specifically, the near-net-shape forming tooling further includes: an edge-opening hammer head 40, the two ends 40a of which conform to the outer peripheral wall of the lower mold 30. See also Figure 7 The outer peripheral wall 30a of the lower mold 30 has a circular outline, and the two ends of the edge-opening hammer head 40 are arc-shaped edges that conform to the outer peripheral wall of the lower mold 30. In the prior art, the two ends of the edge-opening hammer head are straight edges. The edge-opening cone head of this invention adopts an end profile designed to conform to the outer peripheral wall of the lower mold 30, such as an arc-shaped profile, ensuring that the edge-opening hammer head 40 and the outer ring of the lower mold 30 can effectively fit together. This improves the dimensional accuracy and quality uniformity of the outer ring portion between the outer peripheral wall 12b of the second protrusion 12 and the outer peripheral wall 10a of the slab after forming.

[0117] Secondly, the present invention provides a method for preparing an integrated head, which involves forming a blank using the near-net-shape forming fixture described in the first aspect, and then punching and enveloping the blank to obtain an integrated head; the method for forming the blank using the near-net-shape forming fixture includes the following steps:

[0118] (a) In-mold upsetting:

[0119] (a1) Assemble the top block assembly 20 and the lower mold 30 included in the near-net-shape forming tool;

[0120] (a2) The initial blank 50 is placed in the lower mold 30, and the press is driven to make the lower mold 30 and the top block assembly 20 move relative to each other. The lower mold 30 moves and compresses the spring 23. During the mold closing process, the blank is plastically flowed by upsetting in the mold to form the required structure of the intermediate blank 60.

[0121] When the lower die 30 reaches contact with the first step surface 22b of the top block assembly 20, the upsetting process is completed;

[0122] (a3) During the press return stroke, the spring 23 releases its elastic force to push the lower die 30 and the intermediate blank 60 after upsetting in the die away from the top block assembly 20, thereby realizing the demolding of the top block area 21 of the top block assembly and the intermediate blank 60.

[0123] (b) In-mold edge forming: After completing the in-mold upsetting, the intermediate blank 60 located in the lower mold 30 is rotated and edge-shaped to expand the outer diameter of the intermediate blank 60 to a size that matches the inner peripheral wall of the third recessed cavity 32a of the lower mold 30 (the outer diameter of the intermediate blank fills the third recessed cavity 32a, see...). Figure 9 ), thus obtaining 10 slabs.

[0124] It should be noted that this invention provides a manufacturing method for an integrated end cap. This method utilizes a near-net-shape forming fixture designed in this invention. Through precise cooperation between the top block assembly and the lower mold, the complex protruding structure of the required slab blank, including a first protrusion and a second protrusion, can be formed in a single axial mold closing operation. This method, while ensuring forming accuracy and quality consistency, significantly reduces manufacturing difficulty and improves forming efficiency compared to existing technologies. When the press is lifted, the spring mechanism in the fixture can cleverly and quickly separate the lower mold and intermediate blank from the top block assembly, effectively solving the long-standing demolding problem and the problem of slab damage during demolding. Furthermore, the edge-opening hammer in the fixture rotates and opens the intermediate blank in the lower mold, efficiently machining the contour of the portion of the slab blank located on the periphery of the second protrusion without affecting the already formed complex protruding structure. Overall, the manufacturing method of this invention has significant advantages in reducing manufacturing difficulty, improving forming efficiency, ensuring product quality, and improving material utilization.

[0125] Specifically, the top block assembly 20 of the near-net-shape forming tooling is assembled with the lower mold 30; after assembly, the grooves of the manhole seat positions are aligned, specifically, the outer peripheral wall 211b of the annular boss structure 211 of the top block area 21 is provided with multiple concentric concave sections 211b-1, which correspond one-to-one with the multiple centrifugal concave sections 32c1 provided on the inner peripheral wall 32c1 of the fourth recessed cavity 32c, forming each manhole seat.

[0126] In one embodiment, step (a1) specifically includes: after the initial billet 50 is reheated and kept warm in the furnace, it is placed in the assembled lower mold 30. At this time, the spring 23 supports the bottom of the lower mold, and the top block area 21 contacts the bottom of the initial billet 50. After the loading is completed, the overall in-mold upsetting is performed. The press is started and slowly pressed down. The lower mold and the billet are pressed down and the spring 23 is compressed. The top block area 21 squeezes the bottom of the initial billet 50 to form a groove (i.e., forming the first and second protrusions of the pre-formed / to-be-formed slab). When the spring 2H1 is compressed, the bottom of the lower mold 30 falls onto the first step surface 22b of the top block assembly 20. The press continues to press down the billet until the billet fills the fourth sinking cavity 32c of the lower mold, completing the overall in-mold upsetting step and obtaining the intermediate billet 60. Preferably, the initial billet 50 is reheated to 1200-1250°C and kept warm for 20-30 hours. For example, the initial billet 50 is reheated in a furnace to 1200°C, 1210°C, 1220°C, 1230°C, 1240°C, and 1250°C, and held at that temperature for 20h, 22h, 24h, 26h, 28h, and 30h, respectively.

[0127] Preferably, in the rotating edge opening process, the amount of pressure applied per hammer blow is controlled between 50mm and 100mm, and the rotation angle is controlled uniformly between 20° and 30° per hammer blow. By controlling the amount of pressure applied per hammer blow and the rotation angle per hammer blow in the rotating edge opening process, a balance between uniform material flow and efficient deformation is achieved. Its advantage is that it can ensure the forming accuracy and wall thickness uniformity of the outer edge contour of the slab, effectively avoid impact on the already formed complex protruding structure, and at the same time take into account processing efficiency and equipment stability.

[0128] For example, the amount of pressure applied per hammer blow is controlled at 50mm, 60mm, 70mm, 80mm, 90mm, and 100mm. The rotation angle is controlled uniformly at 20°, 22.5°, 24°, and 30° per hammer blow.

[0129] Specifically, in step (b), after the in-mold upsetting is completed, the lower die 30 and the intermediate blank 60 are transferred together to the rotating platform 70 for rotational edge opening. Specifically, the free end face of the intermediate blank 60 is spun open using the edge opening hammer 40: the free end face of the intermediate blank 60 is hammered for the first time using the edge opening hammer 40; then the intermediate blank is rotated by a specific angle (e.g., 20-30°) through the rotating platform 70, and the hammering-rotation operation is repeated until the outer edge of the intermediate blank expands to the target size, that is, the size defined by the inner peripheral wall of the third recessed cavity 32a in the lower die 30, to obtain the slab 10. Furthermore, the lower die 30 and the blank 10 are transferred together onto the unloading platform 90. The outline dimension defined by the outer peripheral wall of the unloading platform is equal to or less than the outline dimension defined by the inner peripheral wall 31a of the hollow area 31 of the lower die. The blank 10 is pushed upward by the unloading platform 90 to separate it from the lower die 30, thereby obtaining a near-net-shape integrated end cap punching blank 10.

[0130] After removing the oxide scale from the slab 10 used for forming the integrated head by grinding, it is directly reheated in a furnace to 950-1000°C for slab forming and integral envelopment forming of the nozzle and manhole positions, thus completing the manufacturing of the integrated head. Exemplarily, it is directly reheated in a furnace to 950°C, 960°C, 970°C, 980°C, 990°C, and 1000°C.

[0131] The preparation method of the present invention further includes: calculating the size of the blank for punching according to the size of the integrated head; for example, the integrated head is a curved head, and the outer diameter of the blank for punching is (3.14×SR+t) / drawing rate, where SR is the inner sphere radius of the integrated head, t is the wall thickness of the integrated head, and the drawing rate is 1.06-1.08.

[0132] The preparation method of the present invention further includes: steel ingot forging to obtain the initial billet 50. The steel ingot forging specifically includes: firstly, billeting, the purpose of which is to homogenize the microstructure and transform the as-cast microstructure generated during the solidification process of the steel ingot into an equiaxed microstructure, and to weld internal cavities, improving the density of the forging. The steel ingot forging process includes: pressing the jaws → upsetting → KD drawing → cutting the jaws and blanking → upsetting → rolling the outer diameter. The weight of the steel ingot used is generally 1.5 times the weight of the final forging to compensate for the amount of water riser removed and the heat loss in each firing. Since the manufactured forging is a solid forging, an upsetting and drawing compaction process is required to ensure the quality of core flaw detection. Generally, the upsetting ratio and drawing ratio are controlled between 2.2 and 2.5. After blanking, the billet is upset and spun, and the upset billet is rolled to achieve the outer diameter dimensions of the initial billet 50 used for in-mold forming.

[0133] Thirdly, the present invention provides an integrated end cap, which is made by punching and enveloping a blank made from the near-net-shape forming tool described in the first aspect; or by the preparation method described in the second aspect.

[0134] The fixtures of the present invention and the manufacturing method using the fixtures are particularly suitable for forming and processing large-sized, complex multi-nozzle integrated heads.

[0135] In some embodiments, the integrated head of the present invention is a large-size, complex multi-nozzle integrated head, wherein "large-size" refers to an inner sphere radius SR ≥ 1000 mm; further, the wall thickness t ≥ 100 mm. "Complex multi-nozzle" refers to the number of nozzles ≥ 4 and the number of manholes ≥ 1 on the integrated head; further, the multi-nozzle includes at least two different sizes of nozzles. For example, see... Figure 11The integrated end cap 00 includes two different specifications of end cap nozzles and one end cap manhole 03. The first specification of end cap nozzles (i.e., first end cap nozzles 01) comprises five units, and the second specification of end cap nozzles (i.e., second end cap nozzles 02) comprises one unit. Specifically, the second end cap nozzle 02 is located at the top center of the integrated end cap, and is formed by punching and completely enclosing the first protrusion 11 of the slab blank 10. The five first end cap nozzles 01 and the end cap manhole 03 are evenly distributed on a ring coaxial with the center of the second end cap nozzle 02. The five first end cap nozzles 01 and the end cap manhole 03 are formed by punching and completely enclosing the second protrusion 12 of the slab blank 10. Specifically, the manhole 03 is formed by a bulge 121 punched on the second protrusion 12 and its overall envelopment, and a first nozzle 01 symmetrically distributed with respect to the manhole 03 is formed by another bulge 121 punched on the second protrusion 12 and its overall envelopment.

[0136] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and comparative examples.

[0137] Example 1:

[0138] This embodiment provides a near-net-shape forming fixture for an integrated end cap punching blank 10, the near-net-shape forming fixture comprising: a top block assembly 20 and a lower die 30; see also Figures 1 to 7 ;

[0139] The top block assembly 20 includes a top block region 21, a top block recessed cavity region 22, and a spring 23; wherein,

[0140] The top block assembly 20 has a central protrusion that forms a top block region 21;

[0141] The top block recessed cavity region 22 is arranged around the top block region 21 and sinks in a stepped manner. The top block recessed cavity region 22 includes, from the outside to the inside in the radial direction, the following:

[0142] The first sunken cavity 22a is distributed in a ring shape;

[0143] The second sinking cavity 22c is distributed in a ring shape, and the bottom surface of the second sinking cavity 22c extends to the root of the top block area 21 and then terminates.

[0144] The first step surface 22b is located between the first sinking cavity 22a and the second sinking cavity 22c, forming a rigid limiting surface when the lower mold 30 moves downward;

[0145] The spring 23 is disposed in the second recessed cavity 22c, and the top end of the spring 23 abuts against the bottom surface of the lower mold 30 and is compressed when the mold is closed;

[0146] The lower mold 30 includes a hollow area 31 and a lower mold cavity area 32; wherein,

[0147] The hollow area 31 is located in the middle of the lower mold 30 and is used to accommodate the top block area 21;

[0148] The lower mold recessed cavity area 32 is arranged around the hollowed-out area 31 and sinks in a stepped manner. The lower mold recessed cavity area 32 includes, from the outside to the inside in the radial direction:

[0149] The third sunken cavity 32a is arranged in a ring shape;

[0150] The fourth recessed cavity 32c is distributed in a ring shape, and the bottom surface of the fourth recessed cavity 32c extends to the boundary of the hollow area 31 and then terminates.

[0151] The second step surface 32b is located between the third sinking cavity 32a and the fourth sinking cavity 32c;

[0152] In this embodiment, the outer peripheral wall 10a of the blank 10 to be formed has a circular outline. The blank 10 includes a first protrusion 11 located in the middle of the blank 10, and a second protrusion 12 distributed in a ring around the first protrusion 11. The first protrusion and the second protrusion have the same height. The second protrusion 12 has two bulges 121 in the ring direction. Each bulge 121 has a radially concentric bulging section 121A and a centrifugal bulging section 121B. The first protrusion 11 and the second protrusion 12 are arranged coaxially about the central axis of the blank 10. The first protrusion 11 is a protruding cylinder. The two bulges 121 are symmetrically arranged about the center of the blank 10 and along the diameter direction. On the second protrusion 12, the non-bulge area has a uniform thickness. The concentric bulging section 121A and the centrifugal bulging section 121B of each bulge 121 are symmetrical arcs, and the two bulges have the same shape.

[0153] Specifically, the top block region 21 includes an upper annular boss structure 211 and a lower column structure 212, wherein,

[0154] The annular boss structure 211 has an open inner cavity 211a. The inner peripheral wall 211a-1 of the open inner cavity 211a and the outer peripheral wall 211b of the annular boss structure 211 are respectively conforming to the outer peripheral wall 11a of the first protrusion 11 and the inner peripheral wall 12a of the second protrusion 12 of the blank 10 to be formed.

[0155] The outer peripheral wall 212b of the column structure 212 is adapted to the shape of the inner peripheral wall 31a of the hollow area 31 of the lower mold 30 and slides in fit.

[0156] In this embodiment, to form the shape of the slab, the inner peripheral wall 32c1 of the fourth recessed cavity 32c conforms to the outer peripheral wall 12b of the second protrusion 12; the outer peripheral wall 211b of the boss structure 211 on the top block area 21 conforms to the inner peripheral wall 12a of the second protrusion 12; the inner peripheral wall 211a-1 of the open inner cavity 211a conforms to the outer peripheral wall 11a of the first protrusion 11; and the inner peripheral wall 32a1 of the third recessed cavity 32a conforms to the outer peripheral wall 10a of the slab 10. The second step surface 22b conforms to the region (such as the annular region) between the root of the second protrusion 12 and the outer peripheral wall 10a of the slab 10 to be formed. The bottom of the open inner cavity 211a conforms to the top surface of the first protrusion 11 in the slab 10 to be formed (the complete surface of the first protrusion 11 that is furthest from the slab 10 base). The bottom of the fourth recessed cavity 32c conforms to the top surface of the second protrusion 12 in the blank 10 to be formed (the complete surface of the second protrusion 12 that is furthest from the base of the blank 10).

[0157] The top block assembly 20 and the lower mold 30 cooperate to form the bulges 121 of the second protrusion 12 on the blank 10.

[0158] Specifically, the outer peripheral wall 211b of the annular boss structure 211 of the top block area 21 is provided with a plurality of concentric concave sections 211b-1. The number, circumferential position and concave contour of the concentric concave sections 211b-1 correspond one-to-one with the concentric bulging sections 121A of each bulge 121 and follow the shape.

[0159] The inner peripheral wall 32c1 of the fourth sinking cavity 32c is provided with a plurality of centrifugal concave sections 32c1-1. The number, circumferential position and concave surface contour of the centrifugal concave sections 32c1-1 correspond one-to-one with the centrifugal outer bulge section 121B of each bulge 121 and follow its shape.

[0160] Specifically, the top block assembly 20 is a coaxial rotating body with a central axis. The top block region 21 and the top block recessed cavity region 22 are coaxially arranged on the central axis of the top block assembly 20. The inner peripheral walls of the first recessed cavity 22a and / or the second recessed cavity 22c are parallel to the central axis of the top block assembly 20. The first step surface 22b is perpendicular to the central axis of the top block assembly 20. The top block region 21 includes an upper boss structure 211 and a lower column structure 212. The open inner cavity 211a is formed within the boss structure 211. The boss structure 211 is an annular boss structure. The column structure 212 is a cylinder.

[0161] To facilitate demolding, the outer peripheral wall of the annular boss structure has a draft angle (e.g., 1 to 7 degrees). The radial dimension of the outer peripheral wall of the annular boss structure decreases monotonically along the demolding direction to form a conical outer wall with a small top and a large bottom. The maximum dimension of the bottom of the annular boss structure (the end closest to the column structure) is equal to the outline dimension of the outer peripheral wall of the column structure 212. The inner peripheral walls of the third recessed cavity 32a, the fourth recessed cavity 32c, and the open inner cavity 211a extend from the opening end toward the bottom wall and have draft angles, for example, a draft angle of 1° to 7°. The radial dimension of the inner peripheral walls of the third recessed cavity 32a, the fourth recessed cavity 32c, and the open inner cavity 211a increases monotonically along the demolding direction to form a conical cavity with a large opening and a small bottom.

[0162] The inner peripheral walls of the first recessed cavity 22a and / or the second recessed cavity 22c are parallel to the central axis of the top block assembly 20. The first stepped surface 22b is perpendicular to the central axis of the top block assembly 20.

[0163] The height 2H3 of the column structure 212 is greater than the depth 2H2 of the second recessed cavity 22c, and the height portion of the column structure 212 that extends beyond the second recessed cavity 22c (2H3-2H2) is adapted to the shape of the inner peripheral wall 31a of the hollow area 31 of the lower mold 30 and can achieve sliding fit.

[0164] The contour dimension defined by the inner peripheral wall 22a1 of the first recessed cavity 22a is not less than the contour dimension defined by the outer peripheral wall 30a of the lower mold 30; and the contour dimension defined by the outer peripheral wall 30a of the lower mold 30 is greater than the contour dimension defined by the inner peripheral wall 22c1 of the second recessed cavity 22c, ensuring that the inner peripheral wall of the outermost recessed cavity (i.e., the first recessed cavity 22a) in the top block recessed cavity area 22 can accommodate the outer peripheral wall of the lower mold 30, and when the mold is closed, the bottom of the lower mold 30 abuts against the bottom of the outermost recessed cavity (i.e., the first recessed cavity 22a) in the top block recessed cavity area 22.

[0165] Specifically, the lower mold 30 is a coaxial rotating body with a central axis, and the hollow area 31 and the lower mold cavity area 32 are coaxially arranged on the central axis of the lower mold 30.

[0166] In this embodiment, the depth of the open cavity 211a of the annular boss structure in the upper part of the top block area 21 is equal to the depth of the fourth recessed cavity 32c of the lower mold 30, ensuring that the first protrusion 11 and the second protrusion 12 in the formed blank have the same height (vertical distance from the root to the top of the protrusion). The difference between the height of the column structure 212 in the lower part of the top block area 21 and the depth of the second recessed cavity 22c of the top block recessed cavity area 22 is equal to the depth of the hollow area 31.

[0167] In this embodiment, the elastic reset structure consists of eight springs 23 evenly arranged in the second recessed cavity 22c, with the top of each spring 23 abutting against the bottom surface of the lower mold 30 when the mold is closed.

[0168] In this embodiment, the integrated end cap 00 to be processed is a curved end cap with the following dimensions: SR = 1230mm, wall thickness t = 100mm. Based on (3.14×SR+t) / drawing rate, and drawing rate = 1.07, the outer diameter dimensions of the blank 10 for punching are calculated as follows: 1D1 = 3700mm, 1H1 = 200mm, 1H2 = 260mm; see [link to documentation]. Figure 1 2D1 = 4000mm, 2D2 = 2400mm, 2D3 = 3000mm, 2H1 = 300mm, 2H2 = 500mm, 2H3 = 600mm, 2H4 = 260mm; see also Figure 3 , 3D1=4000mm, 3D2=3700mm, 3D3=2400mm, 3H1=200mm, 3H2=260mm, 3H3=100mm.

[0169] Example 2

[0170] Example 2 is the same as Example 1, except that the near-net-shape forming fixture further includes an edge-opening hammer head 40, the two ends of which are arc-shaped edges that conform to the outer peripheral wall of the lower mold 30; see also Figure 7 .

[0171] Example 3:

[0172] This embodiment provides a method for preparing an integrated head. A blank is formed using the near-net-shape forming fixture described in the previous embodiment, and then the blank is punched and enveloped to obtain an integrated head. The structure and dimensions of the integrated head and blank in this embodiment are the same as in Embodiment 1 or 2. The process of forming the blank using the near-net-shape forming fixture includes the following steps:

[0173] (a) In-mold upsetting:

[0174] Assemble the top block assembly 20 and the lower mold 30 of the near-net-shape forming tooling described in Embodiment 1 or 2, ensuring that the grooves of the manhole seat (i.e., the outer peripheral wall 211b of the boss structure 211 of the top block area 21 has multiple concentric concave sections 211b-1, and the inner peripheral wall 32c1 of the fourth recessed cavity 32c has multiple centrifugal concave sections 32c1-1) are aligned; see Figure 6 ;

[0175] After the cylindrical initial blank 50 is heated to 1250℃ and held for 20 hours in a reheater, it is placed in the assembled lower mold 30. At this time, the spring 23 supports the bottom of the lower mold, and the top block area 21 contacts the bottom of the initial blank 50. After the material is loaded, the overall in-mold upsetting is carried out. The press is started and slowly pressed down. The lower mold and the blank are pressed down and the spring 23 is compressed. The top block area 21 squeezes the bottom of the initial blank 50 to form a groove (that is, to form the first and second protrusions of the preformed blank). When the spring 2H1 is compressed to 300mm, the bottom of the lower mold 30 falls onto the first step surface 22b of the top block assembly 20. The press continues to press down the blank until the blank fills the fourth sinking cavity 32c of the lower mold, completing the overall in-mold upsetting step and obtaining the intermediate blank 60.

[0176] When the blank fills the fourth recessed cavity 32c of the lower die, the press lifting hammer rises, the press returns, and the spring 23 releases its elastic force to push the lower die 30 and the intermediate blank 60 after upsetting in the die away from the top block assembly 20. The lower die 30 containing the intermediate blank 60 bounces up under the action of the spring 23, separating the top block assembly 20, thus completing the demolding of the top block area 21 of the top block assembly from the intermediate blank 60; see also Figure 8 .

[0177] (b) In-mold edge forming: After completing the in-mold upsetting, the billet 60 and the lower die 30 are hoisted onto the rotating platform 70 as a whole. The press is equipped with edge-opening hammers 40 for rotating edge opening. Each hammer blow controls a reduction of 100mm, and the rotation angle is controlled uniformly. Each hammer blow rotates 20° until the billet fills the third recessed cavity 32a of the lower die 30, that is, the billet size reaches 1D1=3D1=3700mm, 1H1=3H1=200mm, resulting in the slab 10. See [reference needed] Figure 9 .

[0178] The lower mold 30, together with the slab 10, is hoisted onto the unloading platform 90. The unloading platform 90 pushes the slab 10 upwards, completing the demolding of the slab and obtaining a near-net-shape integrated head punching slab 10. After grinding the integrated head punching slab 10 to remove the oxide scale, it is directly returned to the furnace and heated to 1000°C. The slab 10 is punched, and the nozzle and manhole positions are formed by an overall enveloping forming method to complete the manufacturing of the integrated head.

[0179] The physical example of the integrated end cap obtained in this embodiment is as follows: Figure 12 As shown.

[0180] The mechanical properties of the integrated head obtained in this embodiment are as follows: room temperature yield strength 430–454 MPa, room temperature tensile strength 577–591 MPa, 360℃ yield strength 393–401 MPa, and 360℃ tensile strength 562–512 MPa. Furthermore, chemical composition analysis shows that the integrated head forging has a uniform chemical composition. Comparison of mechanical property test results shows that the integrated head forging exhibits uniform mechanical properties, high and homogeneous comprehensive mechanical properties and impact toughness, indicating good overall forging quality. Microstructure, non-metallic inclusions, and grain size analysis show that the internal metallurgical quality of the integrated head forging meets the requirements. The grain size at all inspection locations of the obtained integrated head is greater than grade 5, and the microstructure type is bainitic tempered microstructure. Inclusions of types A, B, C, and D are all within acceptable limits. UT testing and MT and PT testing of the obtained integrated head prove that the internal and surface quality of the obtained integrated head forging is good and meets the requirements.

[0181] Comparative Example 1

[0182] The difference between this comparative example and Examples 1-3 is that the blank 10 for stamping the integrated head 00 is manufactured by free forging followed by machining. The structure and dimensions of the integrated head 00 and blank 10 in this comparative example are the same as those in Examples 1-3.

[0183] The manufacturing cycle of the slab 10 formed by the "free forging + machining" method in this comparative example is at least 1.5 times longer than that of the same specification slab 10 manufactured by the near-net-shape forming tool described in Example 1 or 2 or the manufacturing method described in Example 3.

[0184] 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 near-net-shape forming fixture for an integrated head punching tool, characterized in that, The integral head punching blank (10) to be formed includes a first protrusion (11) located in the middle of the blank, and a second protrusion (12) distributed in a ring around the first protrusion (11); the second protrusion (12) is provided with a plurality of bulges (121) in the circumferential direction, and each bulge (121) has a radially concentric bulging section (121A) and a centrifugal bulging section (121B). The near-net-shape forming tooling includes: a top block assembly (20) and a lower mold (30); The top block assembly (20) includes a top block region (21), a top block recessed cavity region (22), and a spring (23); wherein, The top block assembly (20) has a central protrusion forming a top block area (21); the top block area (21) includes an upper annular boss structure (211) and a lower column structure (212), wherein the annular boss structure (211) has an open inner cavity (211a), the inner peripheral wall (211a-1) of the open inner cavity and the outer peripheral wall (211b) of the annular boss structure (211) are respectively conforming to the outer peripheral wall of the first protrusion (11) and the inner peripheral wall of the second protrusion (12) of the blank (10) to be formed; the outer peripheral wall (212b) of the column structure (212) is adapted to the shape of the inner peripheral wall (31a) of the hollow area (31) of the lower mold (30) and slides in fit; The top block recessed cavity area (22) is arranged around the top block area (21) and sinks in a stepped manner. The top block recessed cavity area (22) includes, from the outside to the inside in the radial direction: The first submerged cavity with a ring-shaped distribution (22a); The second sinking cavity (22c) is distributed in a ring shape, and the bottom surface of the second sinking cavity (22c) extends to the root of the top block area (21) and then terminates. The first step surface (22b) is located between the first sinking cavity (22a) and the second sinking cavity (22c), forming a rigid limiting surface when the lower mold (30) moves downward; The spring (23) is disposed in the second recessed cavity (22c), and the top end of the spring (23) abuts against the bottom surface of the lower mold (30) and is compressed when the mold is closed; The lower mold (30) includes a hollow area (31) and a lower mold cavity area (32); wherein, The hollow area (31) is located in the middle of the lower mold (30) and is used to accommodate the top block area (21). The lower mold recessed cavity area (32) is arranged around the hollowed-out area (31) and sinks in a stepped manner. The lower mold recessed cavity area (32) includes, from the outside to the inside in the radial direction: The third sunken cavity (32a) is distributed in a ring shape. The fourth recessed cavity (32c) is distributed in a ring shape, and the bottom surface of the fourth recessed cavity (32c) extends to the boundary of the hollow area (31) and then terminates. The second step surface (32b) is located between the third sinking cavity (32a) and the fourth sinking cavity (32c); The annular boss structure (211) of the top block area (21) has a plurality of concave sections (211b-1) on its outer peripheral wall (211b). The number, circumferential position and concave contour of the concave sections (211b-1) correspond one-to-one with the concave bulge sections (121A) of each bulge (121) and follow their shape. The inner peripheral wall (32c1) of the fourth sinking cavity (32c) is provided with multiple centrifugal concave sections (32c1-1). The number, circumferential position and concave contour of the centrifugal concave sections (32c1-1) correspond one-to-one with the centrifugal outer bulge section (121B) of each bulge (121) and follow the shape. The inner peripheral wall (32c1) of the fourth recessed cavity (32c) conforms to the outer peripheral wall (12b) of the second protrusion (12) of the blank (10) to be formed; The bottom of the open inner cavity (211a) conforms to the top surface of the first protrusion (11) in the blank (10) to be formed; The height 2H3 of the column structure (212) is greater than the depth (2H2) of the second recessed cavity (22c), satisfying 3H3=2H3-2H2, and the depth of the hollow area (31) is 3H3; and the part of the column structure (212) that exceeds the height of the second recessed cavity (22c) is adapted to the shape of the inner peripheral wall (31a) of the hollow area (31) of the lower mold (30) and can achieve sliding fit; the bottom of the fourth recessed cavity (32c) is conformed to the top surface of the second protrusion (12) in the blank (10) to be formed; when the bottom of the lower mold (30) abuts against the first step surface (22b), the bottom of the fourth recessed cavity (32c) of the lower mold (30) is flush with the root of the annular boss structure (211), and together they form the top surface of the second protrusion (12) on the blank (10); The integrated head is a large-sized, complex multi-nozzle integrated head. The complex multi-nozzle refers to the integrated head having ≥1 manhole and containing at least 2 different sizes of nozzles. The near-net-shape forming fixture can precisely form the complex protruding structure required for the stamping blank of the integrated head through axial one-time mold closing, and reduces the difficulty of demolding, avoiding product defects caused by forced demolding.

2. The near-net-shape forming fixture for integrated head punching according to claim 1, characterized in that, The contour dimension defined by the inner peripheral wall (22a1) of the first sinking cavity (22a) is not less than the contour dimension defined by the outer peripheral wall (30a) of the lower mold (30), and the contour dimension defined by the outer peripheral wall (30a) of the lower mold (30) is greater than the contour dimension defined by the inner peripheral wall (22c1) of the second sinking cavity (22c).

3. The near-net-shape forming fixture for integrated head punching according to claim 1, characterized in that, The inner peripheral wall (32a1) of the third recessed cavity (32a) conforms to the outer peripheral wall (10a) of the blank (10) to be formed.

4. The near-net-shape forming fixture for integrated head punching according to claim 1, characterized in that, The near-net-shape forming tool also includes: an edge-opening hammer (40), the two ends of which conform to the outer peripheral wall of the lower mold (30).

5. A method for preparing an integrated end cap, characterized in that, Using the near-net-shape forming fixture according to any one of claims 1-4 to form a blank, and then punching and enveloping the blank to obtain an integrated head; forming the blank using the near-net-shape forming fixture includes the following steps: (a) In-mold upsetting: Assemble the top block assembly (20) of the near-net-shape forming tooling with the lower mold (30); The initial blank (50) is placed in the lower mold (30), and the press is driven to make the lower mold (30) and the top block assembly (20) move relative to each other. The lower mold (30) moves and compresses the spring (23). During the mold closing process, the blank is plastically flowed by upsetting in the mold to form the required structure of the intermediate blank (60). When the lower die (30) reaches contact with the first step surface (22b) of the top block assembly (20), the upsetting is completed; During the press return stroke, the spring (23) releases its elastic force to push the lower die (30) and the intermediate blank (60) after upsetting in the die away from the top block assembly (20), thereby realizing the demolding of the top block area of ​​the top block assembly from the intermediate blank (60); (b) In-mold edge forming: After the in-mold upsetting is completed, the intermediate blank (60) located in the lower mold (30) is rotated and edged to expand the outer diameter of the intermediate blank (60) to the size that matches the inner peripheral wall of the third recessed cavity (32a) of the lower mold (30) to obtain the slab (10).

6. The method for preparing the integrated head according to claim 5, characterized in that, In the rotating edge opening process, the amount of pressure applied by each hammer is controlled between 50mm and 100mm, and the rotation angle is controlled uniformly at 20°-30° per hammer.

7. An integrated end cap, characterized in that, The integrated head is made by punching and enveloping a blank made from a near-net-shape forming tool as described in any one of claims 1-4; or by the preparation method as described in any one of claims 5-6.

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