Weldless liquid filling machining method for high-temperature alloy cone

Abstract

The invention discloses a weldless liquid filling processing method for a high-temperature alloy cone, which comprises the following steps of: firstly, processing a disc-shaped blank by adopting a plate, then, carrying out primary forming, drawing a cylindrical groove in the central area of the disc-shaped blank by adopting a stretching and liquid filling combined mode, arranging a circle of flange edge on the outer side of the cylindrical groove, and then, carrying out secondary forming, so as to obtain the weldless liquid filling processing method for the high-temperature alloy cone. A conical groove is formed in the center area of the bottom face of the cylindrical groove in a stretching and liquid filling combined mode, and finally a circle of storage bag of a trapezoidal structure is formed between the conical groove and the flange edge; and thirdly, forming for the third time, and forming semi-elliptic molded surfaces in the areas of the cylindrical groove and the conical groove in a stretching and liquid filling combined mode. The machining method is free of welding seams on the whole, the surface quality is high, the molded surface machining quality is good, and wall thickness control meets the design requirement.

Description

Technical Field

[0001] This invention belongs to the field of special processing technology for high-temperature alloys, and specifically relates to a cold forming process for high-temperature alloy cones. Background Technology

[0002] A cone used in aircraft engines, such as Figure 1 As shown, the main body of the part has a semi-elliptical cross-section. The diameter of the opening section (large diameter end) is Φ400mm, and a hole is opened at the center of the small diameter end. The major axis of the ellipse is approximately 265mm (i.e., the depth is 265mm), and the depth-to-diameter ratio is approximately 0.7. The material thickness is only 0.8mm, and the final thickness after molding is required to be no less than 0.84t (t is the final thickness of the conical part). The depth-to-diameter ratio is 0.8, and the wall thickness reduction is required to be no more than 0.15t (t is the final thickness of the conical part). The technical requirements for maintaining the wall thickness after molding are relatively high.

[0003] Because the part has a high aspect ratio and is made of high-temperature alloy, traditional forming methods typically divide the part into two sections, the upper and lower sections, to ensure that the wall thickness meets the requirements after forming. The upper section is formed using a sheet metal stretching process, while the lower section is formed using sheet metal welded and then expanded. Finally, the two sections are welded together at the dividing point to form a conical part. However, traditional forming methods result in one straight weld seam and one circumferential weld seam on the part, a lengthy processing procedure, multiple weld seams, low overall part processing efficiency, thermal deformation of the profile, large fluctuations in wall thickness, and instances of excessive thinning in certain areas.

[0004] For the reasons mentioned above, it is necessary to study a seamless, efficient integral forming method for processing high-temperature alloy parts with similar structural features. Summary of the Invention

[0005] This invention aims to provide a seamless liquid filling process for high-temperature alloy cones, solving the problems of large depth-to-diameter ratio, thin material wall thickness, and high requirements for forming thickness control. It ensures that the cone thickness accuracy meets the requirements after forming, improves processing efficiency, reduces processing costs, and eliminates welds, thereby improving processing quality.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for seamless liquid filling machining of a high-temperature alloy cone includes the following steps:

[0008] Step 1, Raw material preparation: Disc-shaped raw materials are processed from sheet metal.

[0009] Step 2, the first forming, uses a combination of stretching and liquid filling to stretch a cylindrical groove in the center area of ​​the disc-shaped blank, with a flange edge around the outside of the cylindrical groove;

[0010] Step 3, second molding, again using a combination of stretching and liquid filling to stretch a conical groove in the center area of ​​the bottom surface of the cylindrical groove, and finally forming a trapezoidal storage bag between the conical groove and the flange edge;

[0011] Step four, the third molding, uses a combination of stretching and liquid filling to form a semi-elliptical surface in the cylindrical and conical groove areas.

[0012] Furthermore, it also includes step five, which involves machining a hole at the end of the semi-elliptical surface.

[0013] Alternatively, in step one, the dimensions of the disc-shaped blank are calculated using the equal volume method based on the final volume of the high-temperature alloy cone.

[0014] Alternatively, in step two, the stretching die includes a first punch, a first die, and a first pressure seal. The lower outer surface of the first punch is a cylindrical forming surface, the upper surface of the first die includes a cylindrical forming groove, the bottom of the cylindrical forming groove is provided with a filling port, and the first pressure seal is an annular part with an inner annular hole forming a pressing channel for the first punch and its axial lower end face forming a sealing and pressing surface that mates with the upper surface of the first die.

[0015] Alternatively, in step three, the stretching die includes a second concave die, a second convex die, and a second pressure seal. The lower outer surface of the second convex die is a conical forming surface, and the upper surface of the second concave die includes a cylindrical groove. The central area of ​​the bottom surface of the cylindrical groove has a conical forming groove, and the bottom of the conical forming groove is provided with a filling port. The second pressure seal is a variable diameter annular part, whose inner annular hole forms the pressing channel of the second convex die. The variable diameter step surface on its outer annular surface cooperates with the upper surface of the second concave die to form a sealing and pressing surface, and its axial lower end surface forms a sealing and pressing surface with the bottom surface of the cylindrical groove.

[0016] Alternatively, in step four, the stretching die includes a third punch, a third die, and a pressure ring. The lower end surface of the third punch is an elliptical profile, and the upper end surface of the third die includes an elliptical groove with a filling port at the bottom. The pressure ring is an annular piece, and its axial lower end surface forms a sealing and pressing surface with the upper end surface of the third die. Its inner annular hole forms a pressing channel for the third punch.

[0017] Traditional segmented forming and welding processes are inefficient, labor-intensive, and require multiple welding and heat treatment processes, resulting in unsatisfactory surface quality of the parts. The processing method of this invention solves the problems of low processing efficiency, high processing costs, and poor workpiece quality associated with segmented forming and welding of such parts.

[0018] The advantages of this invention are:

[0019] (1) It solves the risk of dimensional reduction in similar high aspect ratio and thin-walled parts, and effectively ensures product processing quality;

[0020] (2) High efficiency: The traditional segmented forming and welding process is changed to an integral liquid filling and stretching process, the parts are seamless, the surface quality is high, and the surface processing quality is good.

[0021] (3) On the one hand, a trapezoidal material storage structure is adopted for the elliptical cross section to ensure uniform material distribution and flow during the stretching process, thereby controlling the final forming thickness to meet the requirements and preventing local ultra-thinness; on the other hand, it is divided into three stretching + liquid filling molding. Liquid filling reduces deformation defects caused by excessive local temperature during stretching. On the other hand, compared with traditional rigid molds, the pressure of liquid in all directions in the mold cavity is relatively uniform, making it less likely to produce surface wrinkles and resulting in good forming surface quality. Attached Figure Description

[0022] Figure 1 This is a model drawing of the cone-shaped part;

[0023] Figure 2 This is a drawing of the stretching die for the first forming process.

[0024] Figure 3 This is a drawing of the stretching die for the second forming process;

[0025] Figure 4 This is a drawing of the stretching die for the third forming process;

[0026] Figure 5 This is a rough drawing of the material during the forming of the cone-shaped part;

[0027] Figure 6 This is a schematic diagram of the three-stage molding process;

[0028] In the figure: 1-first punch, 2-first die, 3-first pressure seal, 4-second die, 5-second punch, 6-second pressure seal, 7-third punch, 8-drainage pipe, 9-third die, 10-pressure ring. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0030] The design principle of the seamless material storage forming method for semi-elliptical cones described in this invention is as follows: A disc-shaped sheet is first formed into a basin-shaped structure with a diameter of 300mm and a depth of 100mm. Then, the raw material is formed a second time, creating a "material storage bag" with trapezoidal cross-sectional characteristics. In the subsequent third forming process, a mold identical to the final surface structure of the part is used for final surface finishing. The material storage bag directly participates in the forming process, providing the necessary raw materials and ensuring that the part's thinning meets requirements.

[0031] The processing method of this invention includes the following aspects:

[0032] (1) Mold: Based on the structural characteristics of the part, which is semi-elliptical and has a large depth-to-diameter ratio, a total of three sets of forming stretching dies were designed. The first set is a pre-stretching die, the second set is a material storage stretching die, and the third set is a final surface forming stretching die. The third set of drawing dies makes the material storage bag formed by the second set of material storage stretching dies fit the surface, which is equivalent to a forming die, and completes the final forming of the part surface according to the final processing surface.

[0033] like Figure 2 The first pre-stretching mold includes an upper template, a lower template, a first punch 1, a hydraulic column, a first die 2, and a first edge-pressing seal 3. The lower outer surface of the first punch 1 is a cylindrical forming surface, and the upper surface of the first die 2 includes a cylindrical forming groove. The bottom of the cylindrical forming groove is provided with a filling port. The first edge-pressing seal 3 is an annular part, and its inner annular hole forms a downward pressing channel for the first punch 1. Its axial lower end face forms a sealing and pressing surface that mates with the upper end face of the first die 2. The first die 2 is fixed on the lower template. The distance between the upper and lower templates is controlled by the hydraulic column. The upper template has a through hole, and the first punch 1 is located in the through hole. A seal is installed on the circumferential surface of the first punch 1 to form a seal with the inner wall of the through hole. The first edge-pressing seal 3 is fixed on the upper template.

[0034] like Figure 3The second set of storage and stretching molds includes an upper template, a lower template, a second concave mold 4, a second convex mold 5, and a second pressing seal 6. The lower outer surface of the second convex mold 5 is a conical forming surface. The upper surface of the second concave mold 4 includes a cylindrical groove. The center area of ​​the bottom surface of the cylindrical groove has a conical forming groove. The bottom of the conical forming groove is provided with a liquid filling port. The second pressing seal 6 is a variable diameter (variable outer diameter) annular part. Its inner annular hole forms the pressing channel of the second convex mold 5. The variable diameter step surface on its outer annular surface cooperates with the upper end surface of the second concave mold 4 to form a sealing and pressing surface. Its axial lower end surface forms a sealing and pressing surface with the bottom surface of the cylindrical groove. The second concave mold 4 is fixed on the lower template. The second convex mold 5 passes through the through hole on the upper template, and a seal is provided between the second convex mold 5 and the inner wall of the through hole. The upper end of the second pressing seal 6 is fixed on the upper template.

[0035] like Figure 4 The final forming stretching die includes a pressure plate, a third punch 7, a drain pipe 8, a pressure ring 10, and a third die 9. The lower end surface of the third punch 7 is an elliptical forming surface, and the upper end surface of the third die 9 includes an elliptical groove with a filling port at the bottom. The pressure ring 10 is an annular piece, and its axial lower end surface forms a sealing and pressing surface with the upper end surface of the third die 9. Its inner annular hole forms a pressing channel for the third punch 7. The third die 9 is fixed by the pressure plate through the protrusion at its lower end.

[0036] (2) Preparation of molding blanks: Calculate the volume according to the final required size of the part, convert it into the volume of a disc-shaped blank of the same thickness according to the equal volume method, and calculate the required size of the blank. Obtain the disc-shaped blank by cutting the plate.

[0037] (3) First molding: The disc-shaped material is placed in the cylindrical groove of the first concave mold 2 of the first set of pre-stretching molds. The pressing pressure is set to 20-40 MPa. Liquid is injected into the concave mold cavity between the cylindrical groove and the disc-shaped material through the liquid filling port on the bottom surface of the cylindrical groove. Pressing is carried out while ensuring uniform mold gap. The pressing depth is 100 mm and the pressing diameter is 300 mm. The first punch 1 moves down until it closes with the first concave mold 2. The liquid in the concave mold cavity flows out of the first concave mold 2 from the liquid filling port on the bottom surface of the cylindrical groove. After stretching, a cylindrical basin-like structure is formed with a flange edge around its outer edge.

[0038] (4) Second molding: The second punch 5 in the storage stretching die is used to press the blank after the first molding. The second pressing seal 6 presses the flange edge and performs a second pressing in the central area of ​​the basin with a diameter of 300mm to form a trapezoidal storage bag to ensure the formation of the final storage bag. During the second molding process, liquid is also injected into the cavity of the second die 4 through the liquid filling port at the bottom of the cone-shaped molding groove. When the second punch 5 and the second die 4 are closed, the storage stretching is completed and the liquid is discharged from the second die 4 through the liquid filling port.

[0039] (5) The third molding process uses the final surface forming stretching mold, namely the third punch 7, to stretch the entire surface size and combine it with liquid filling and back expansion to press the storage bag into the surface, ensuring that the part surface is consistent with the design requirements. During the pressing process, the pressure ring 10 presses the flange edge, and the third punch 7 is pressed down until it closes with the third concave mold 9. The liquid is discharged from the drain pipe 8.

[0040] (6) Make a hole at the small outer diameter end of the elliptical cone after the third molding.

[0041] like Figure 6 As shown, the process of three molding stages is illustrated, where D represents the inner diameter of the storage bag during the second molding stage, H represents the height of the storage bag, and P represents the pressure being uniformly distributed during liquid filling molding. Figure 6 The image shows a magnified view of the relationship between the shape of the storage bag and the third punch 7 during the third forming process.

[0042] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. A method for seamless liquid filling machining of a high-temperature alloy cone, characterized in that, Includes the following steps: Step 1, Raw material preparation: Disc-shaped raw materials are processed from sheet metal. Step 2, the first forming, uses a combination of stretching and liquid filling to stretch a cylindrical groove in the center area of ​​the disc-shaped blank, with a flange edge around the outside of the cylindrical groove; Step 3, second molding, again using a combination of stretching and liquid filling to stretch a conical groove in the center area of ​​the bottom surface of the cylindrical groove, and finally forming a trapezoidal storage bag between the conical groove and the flange edge; Step four, the third molding, uses a combination of stretching and liquid filling to form a semi-elliptical surface in the cylindrical and conical groove areas.

2. The method for seamless liquid filling machining of a high-temperature alloy cone according to claim 1, characterized in that: It also includes step five, which involves machining a hole at the end of the semi-elliptical surface.

3. The method for seamless liquid filling machining of a high-temperature alloy cone according to claim 1, characterized in that: In step one, the dimensions of the disc-shaped blank are calculated using the equal volume method based on the final volume of the high-temperature alloy cone.

4. The method for seamless liquid filling machining of a high-temperature alloy cone according to claim 1, characterized in that: In step two, the stretching die includes a first punch (1), a first die (2) and a first pressing seal (3). The lower outer surface of the first punch (1) is a cylindrical forming surface, the upper surface of the first die (2) includes a cylindrical forming groove, the bottom of the cylindrical forming groove is provided with a liquid filling port, and the first pressing seal (3) is an annular part. Its inner annular hole forms the pressing channel of the first punch (1), and its axial lower end face forms a sealing pressing surface that cooperates with the upper end face of the first die (2).

5. The method for seamless liquid filling machining of a high-temperature alloy cone according to claim 1, characterized in that: In step three, the stretching die includes a second concave die (4), a second punch (5), and a second pressing seal (6). The lower outer surface of the second punch (5) is a conical shaped surface. The upper surface of the second concave die (4) includes a cylindrical groove. The center area of ​​the bottom surface of the cylindrical groove has a conical shaped groove. The bottom of the conical shaped groove is provided with a liquid filling port. The second pressing seal (6) is a variable diameter annular part. Its inner annular hole forms the pressing channel of the second punch (5). The variable diameter step surface on its outer annular surface cooperates with the upper surface of the second concave die (4) to form a sealing and pressing surface. Its axial lower end surface forms a sealing and pressing surface with the bottom surface of the cylindrical groove.

6. The method for seamless liquid filling machining of a high-temperature alloy cone according to claim 1, characterized in that: In step four, the stretching die includes a third punch (7), a third die (9), and a pressure ring (10). The lower end surface of the third punch (7) is an elliptical surface, and the upper end surface of the third die (9) includes an elliptical groove with a liquid filling port at the bottom. The pressure ring (10) is an annular piece, and its axial lower end surface forms a sealing and pressing surface with the upper end surface of the third die (9). Its inner annular hole forms a pressing channel for the third punch (7).

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