A cladding assembly for near-net-shape hot isostatic pressing of thin-walled casings

Abstract

This utility model belongs to the field of additive manufacturing technology, specifically disclosing a cladding assembly for near-net-shape hot isostatic pressing (HIP) forming of thin-walled engine casings. It comprises a rigid cladding consisting of an outer and inner control cladding and a cladding cover, and a flexible cladding consisting of a powder-filling cladding and cladding end caps. The rigid cladding has internal dimensions matched to the target engine casing, achieving precise forming of complex shapes through irregularly shaped grooves. It is made of medium-high carbon steel to ensure structural stability during HIP. The flexible cladding is made of low-carbon steel and connects to the rigid cladding through a stepped hollow structure, shrinking under high temperature and pressure to dynamically replenish powder. This utility model, through its rigid-flexible design, solves the problems of uneven powder filling and insufficient cladding shrinkage precision in traditional processes, significantly improving the forming accuracy of thin-walled engine casings, substantially enhancing the near-net-shape forming accuracy and production efficiency of HIP, and reducing processing costs. It is suitable for the precision manufacturing of complex structural components such as thin-walled engine casings.

Description

Technical Field

[0001] This utility model belongs to the field of additive manufacturing technology, specifically relating to a cladding assembly for near-net-shape hot isostatic pressing of thin-walled casings. Background Technology

[0002] Against the backdrop of the aerospace industry's rapid development towards high performance and lightweight design, the performance enhancement of aero engines, as the core power unit of aircraft, places stringent demands on the manufacturing processes of key components. The engine casing, as the "skeleton" of the aero engine, not only plays a crucial role in supporting the internal rotor system and containing high-temperature combustion gases, but also needs to maintain structural integrity under extreme operating conditions (such as high temperature, high pressure, and high-frequency vibration environments). Furthermore, as the design requirements for thrust-to-weight ratio in aero engines continue to increase, the wall thickness of the casing is gradually decreasing, while its external structure exhibits complex features such as irregularly shaped bosses, deep cavities, and thin-walled reinforcing ribs. Traditional manufacturing processes are no longer sufficient to meet its performance and precision requirements.

[0003] Currently, traditional casing manufacturing primarily employs precision casting or partial forging processes. Precision casting, using molds, allows for the one-time molding of complex structures, but uneven shrinkage during molten metal solidification easily leads to internal defects such as shrinkage cavities and porosity. According to statistics from aero-engine manufacturers, thin-walled casings produced using precision casting have an internal defect rate as high as 18%–25%, resulting in a 30%–40% reduction in fatigue life. Furthermore, precision castings exhibit poor microstructure uniformity, with mechanical property differences exceeding 15% across different areas, making it difficult to meet the stringent reliability requirements of aero-engines. While partial forging improves material density, it requires a large machining allowance (typically 3mm–5mm per side), resulting in a material utilization rate of only 35%–40%. Moreover, the metal flow lines are easily disrupted during forging, causing anisotropy in the mechanical properties of the component, increasing the difficulty and cost of subsequent processing.

[0004] Hot isostatic pressing (HIP), an advanced powder metallurgy process, encapsulates metal powder within a casing and densifies it through plastic deformation, diffusion, and recrystallization under high pressure and temperature. The resulting parts can achieve a relative density of over 99.5% and exhibit excellent isotropic properties, thus attracting widespread attention in the aerospace component manufacturing field. However, for complex structural components such as thin-walled casings, the application of HIP still faces significant challenges. This is because the narrow powder cavity and complex internal contours of thin-walled casings make it difficult to uniformly fill the powder during the loading process. Experimental data shows that when using traditional casings for HIP, the powder filling density varies significantly in different parts of the casing, ultimately causing the part's wall thickness deviation to exceed design requirements. Furthermore, the shrinkage behavior of traditional casings under high temperature and pressure is difficult to control precisely, requiring extensive machining after HIP to correct dimensions, which not only prolongs the production cycle but also increases processing costs.

[0005] In summary, existing technologies cannot achieve high-precision near-net-shape forming of thin-walled casings during hot isostatic pressing. There is an urgent need to develop a new type of casing assembly to solve the above-mentioned technical problems and achieve high-precision near-net-shape forming of thin-walled casings.

[0006] In view of this, this utility model is hereby proposed. Utility Model Content

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a cladding assembly for near-net-shape hot isostatic pressing of thin-walled casings. It mainly solves the technical problems existing in the hot isostatic pressing process of thin-walled casings, such as uneven powder filling, insufficient cladding shrinkage accuracy, and high difficulty in subsequent processing. Through unique structural design and material selection, it improves the uniformity of powder filling, increases production efficiency, reduces processing costs, and achieves high-precision near-net-shape forming of thin-walled casings, thereby promoting the advancement of manufacturing technology for core components of aero-engines.

[0008] The objective of this utility model is achieved through the following technical solution:

[0009] This utility model provides a cladding assembly for near-net-shape hot isostatic pressing of thin-walled casings, comprising:

[0010] The outer control type sleeve has an irregularly shaped groove on its inner surface that corresponds to the irregularly shaped protrusion on the outer surface of the target casing.

[0011] The inner control type sleeve is coaxially nested inside the outer control type sleeve;

[0012] The top cover of the sleeve is used to connect the upper ends of the outer control sleeve and the inner control sleeve;

[0013] The powder injection sleeve is connected to the control chamber formed by the outer control sleeve and the inner control sleeve through the sleeve cover;

[0014] End cap for sealing the upper end of the powder injection sleeve;

[0015] The outer control type sleeve, the inner control type sleeve, and the sleeve cover are fixedly connected to form a rigid sleeve that matches the target casing; the powder injection sleeve and the sleeve end cover are fixedly connected to form a retractable flexible sleeve, and the flexible sleeve is set at the sleeve cover, together constituting the overall sleeve assembly.

[0016] Furthermore, the outer diameter of the external control type sleeve is 1.2 to 1.4 times the maximum outer diameter of the target casing, and the inner diameter matches the outer surface size of the target casing.

[0017] Furthermore, the outer diameter of the internal control type sleeve is the same as the inner diameter of the target casing, and the inner diameter is 0.6 to 0.8 times the minimum inner diameter of the target casing.

[0018] Furthermore, both the upper and lower end faces of the outer control type sleeve and the upper and lower end faces of the inner control type sleeve are machined with a semi-V-shaped annular bevel.

[0019] Furthermore, the bevel angle of the semi-V-shaped annular bevel is 40° to 60°, and the bevel depth is 4mm to 6mm.

[0020] Furthermore, the cover of the sleeve is an annular structure with a thickness of 4mm to 6mm, and the inner and outer diameters are respectively provided with semi-V-shaped annular bevels that match the outer control type sleeve and the inner control type sleeve.

[0021] Furthermore, the cover of the sleeve is provided with 4 to 8 through holes evenly distributed along the annular structure, and a powder injection sleeve is connected to the through holes.

[0022] Furthermore, the powder injection sleeve is a hollow stepped structure with a wall thickness of 4mm to 6mm and a total length of 100mm to 120mm;

[0023] The lower half of the powder injection sleeve has a length of 20mm to 30mm, and its outer diameter matches the through holes arranged on the upper cover of the sleeve; the inner diameter of the upper half of the powder injection sleeve is larger than the outer diameter of the lower half.

[0024] Furthermore, the end cap of the sleeve is a circular plate with a wall thickness of 4mm to 6mm, and a powder injection hole with a diameter of 15mm to 20mm is provided in the center; the outer diameter of the end cap of the sleeve and the inner diameter of the upper half of the powder injection sleeve have a tolerance of ±0.5mm, and a sealing structure is formed after welding.

[0025] Furthermore, the outer control type sleeve, the inner control type sleeve, and the sleeve cover are made of medium and high carbon steel; the powder injection sleeve and the sleeve end cap are made of low carbon steel.

[0026] Preferably, the outer control sleeve, the inner control sleeve, and the sleeve cover are made of 45 steel or 50 steel; the powder injection sleeve and the sleeve end cap are made of 20 steel or Q235 steel.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The sheathing assembly provided by this utility model mainly consists of a rigid sheath (controlled sheath) formed by an outer controlled sheath, an inner controlled sheath, and a sheath cover, and a flexible sheath (extrusion sheath) formed by a powder injection sheath and a sheath end cover. The rigid sheath's internal dimensions precisely match the target casing, and its complex shape is accurately formed through irregularly shaped grooves. Made of medium-high carbon steel that is not easily deformed, it remains stable during hot isostatic pressing, avoiding dimensional deviations caused by sheath shrinkage and significantly reducing subsequent machining. The flexible sheath, made of low-carbon steel, shrinks under high temperature and pressure, dynamically injecting internal powder into the controlled sheath to fill the powder filling gaps, solving the problem of uneven powder filling in traditional processes. The combination of these two components not only improves powder filling uniformity and ensures part quality but also achieves high-precision near-net-shape forming of thin-walled casings, significantly improving production efficiency, reducing processing costs, and promoting technological advancements in the manufacturing of core components (casings) for aero-engines. Attached Figure Description

[0029] The accompanying drawings are incorporated in and form part of this specification, and together with the description, serve to explain the principles of this invention.

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the thin-walled casing structure of a certain target model;

[0032] Figure 2 This is a schematic diagram of the assembly of the cladding assembly for near-net-shape hot isostatic pressing of thin-walled casings according to this utility model;

[0033] Figure 3 This is a schematic diagram of the external control type sleeve structure in the sleeve assembly of this utility model;

[0034] Figure 4 This is a schematic diagram of the cross-sectional structure of the outer control type sleeve in the sleeve assembly of this utility model;

[0035] Figure 5 This is a schematic diagram of the internal control type sleeve structure in the sleeve assembly of this utility model;

[0036] Figure 6 This is a schematic diagram of the upper cover structure of the cover assembly of this utility model;

[0037] Figure 7 This is a schematic diagram of the powder injection sleeve structure in the sleeve assembly of this utility model;

[0038] Figure 8 This is a schematic diagram of the end cap structure in the sleeve assembly of this utility model.

[0039] in:

[0040] 1 is an external control type sleeve; 2 is an internal control type sleeve; 3 is the top cover of the sleeve; 4 is the powder injection sleeve; 5 is the end cap of the sleeve; 31 is a through hole; 41 is the lower half; 42 is the upper half; 51 is the powder injection hole. Detailed Implementation

[0041] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this invention. Rather, they are merely examples of apparatuses consistent with some aspects of this invention as detailed in the appended claims.

[0042] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0043] Example

[0044] Please see Figures 1-8This utility model provides a cladding assembly for near-net-shape hot isostatic pressing of thin-walled casings, mainly composed of a rigid cladding (shape-controlled cladding) and a flexible cladding (extrusion cladding). The rigid cladding is made of medium-high carbon steel and customized according to the actual dimensions and shape characteristics of the target casing, with its internal space precisely matching the casing contour. The flexible cladding is made of low-carbon steel and serves as a dynamic powder supply unit, achieving a sealed connection with the rigid cladding. Through this configuration, during the hot isostatic pressing process, as the high-temperature and high-pressure environment forms, the flexible cladding, being made of low-carbon steel, undergoes plastic shrinkage deformation first, continuously injecting the stored metal powder into the rigid cladding. Meanwhile, the rigid cladding, thanks to the high strength of medium-high carbon steel, maintains a stable geometric shape under high temperature and pressure, ensuring the dimensional accuracy of key structures such as complex bosses and reinforcing ribs on the outer surface of the casing. In addition, through the dynamic powder replenishment mechanism of the flexible sleeve, the powder inside the rigid sleeve is uniformly compacted, effectively eliminating the density difference caused by uneven powder loading in the traditional process. This ensures that there will be no problem of uneven powder filling density inside the rigid sleeve, thereby improving production efficiency and reducing manufacturing difficulty and production cost.

[0045] In this embodiment of the utility model, the rigid sleeve consists of an outer control sleeve 1, an inner control sleeve 2, and a sleeve cover 3. Wherein, as... Figure 3 , 4 As shown, the inner surface of the outer control sleeve 1 is machined with a groove corresponding to the irregularly shaped protrusion on the outer surface of the target casing; the structure of the inner control sleeve 2 is shown in Figure 5, which is coaxially nested inside the outer control sleeve 1; the sleeve cover 3 is used to fix the upper ends of the outer control sleeve 1 and the inner control sleeve 2. It should be noted that the internal space of the rigid sleeve depends on the target model casing (see Figure 5). Figure 1 The external dimensions are customized, which will not be described in detail here.

[0046] Specifically, in this embodiment of the invention, the outer diameter of the outer control sleeve 1 should be 1.2 to 1.4 times the maximum outer diameter of the target casing (e.g., if the outer diameter of the target casing is 800 mm, the outer diameter of the outer control sleeve 1 can be set to 960 mm), and a semi-V-shaped annular bevel is machined on both its upper and lower end faces; the outer diameter of the inner control sleeve 2 is the same as the inner diameter of the target casing, and the inner diameter is 0.6 to 0.8 times the minimum inner diameter of the target casing (by limiting the size relationship between the outer control sleeve 1 and the inner control sleeve 2 and the target casing, the control sleeve has a certain thickness to prevent deformation during hot isostatic pressing, thereby ensuring the specifications of the target product), and its upper and lower end faces are also provided with a semi-V-shaped annular bevel; the sleeve cover 3 is an annular structure with a thickness of 4 mm to 6 mm, and the inner and outer diameters are respectively provided with semi-V-shaped annular bevels that match the outer control sleeve 1 and the inner control sleeve 2. Furthermore, the outer control sleeve 1, the inner control sleeve 2, and the sleeve cover 3 are made of 45 steel or 50 steel. When the three are assembled and welded to form a rigid sleeve, the semi-V-shaped annular bevel on the upper end face of the outer control sleeve 1 is used to mate with the semi-V-shaped annular bevel on the outer diameter of the sleeve cover 3; the semi-V-shaped annular bevel on the lower end face of the outer control sleeve 1 is used to mate with the semi-V-shaped annular bevel on the lower end face of the inner control sleeve 2; and the semi-V-shaped annular bevel on the upper end face of the inner control sleeve 2 is used to mate with the semi-V-shaped annular bevel on the inner diameter of the sleeve cover 3.

[0047] Preferably, the bevel angle of the upper half-V-shaped annular bevel is generally set to 40° to 60°, and the bevel depth is generally set to 4mm to 6mm.

[0048] Furthermore, such as Figure 6 As shown in the embodiment of this utility model, 4 to 8 through holes 31 are evenly distributed along the annular structure on the cover 3 of the sleeve, and a powder injection sleeve 4 is sealed and connected at each through hole 31.

[0049] In this embodiment of the invention, the flexible sheath consists of a powder injection sheath 4 and a sheath end cap 5, both made of 20 steel or Q235 steel. The powder injection sheath 4 communicates with the control chamber of the rigid sheath through a pre-set through hole 31 in the sheath end cap 3; the sheath end cap 5 seals the upper end of the powder injection sheath 4.

[0050] Specifically, such as Figure 7 As shown, in this embodiment of the present invention, the powder injection sleeve 4 is a hollow stepped structure with a wall thickness of 4mm to 6mm and a total length of 100mm to 120mm. The outer diameter of the lower half 41 of the powder injection sleeve 4 matches the through hole of the sleeve cover 3, and the length of the lower half 41 is generally set to 20mm to 30mm. The inner diameter of the upper half 42 of the powder injection sleeve 4 is larger than the outer diameter of the lower half 41, and the internal volume of the upper half 42 is preferably 1.05 to 1.25 times the amount of powder required for the rigid sleeve.

[0051] Furthermore, such as Figure 8As shown, in this embodiment of the utility model, the end cap 5 is a circular plate with a wall thickness of 4mm to 6mm, and a powder injection hole 51 with a diameter of 15mm to 20mm is provided in the center; the outer diameter of the end cap 5 and the inner diameter of the powder injection sleeve 4 are controlled within ±0.5mm, and the two are welded together to form a flexible sleeve.

[0052] It should be noted that the molding process of the sheath assembly provided in this utility model embodiment is as follows: First, based on the external dimensions of the target model casing, combined with its weight and the powder shrinkage rate during isostatic pressing, the components of the sheath assembly (outer control type sheath 1, inner control type sheath 2, sheath top cover 3, powder injection sheath 4, and sheath end cover 5) are designed and processed in a targeted manner; then, each component is shot peened to effectively eliminate the oxide layer on the material surface and improve the fatigue strength of the sheath assembly; subsequently, a cleaning process is carried out to ensure that the inner surface of the sheath assembly is not contaminated by foreign matter; finally, the above five components are assembled and welded to obtain the sheath assembly for near-net-shape hot isostatic pressing of thin-walled casings.

[0053] The specific process for manufacturing a certain type of thin-walled casing using hot isostatic pressing (HIP) for the cladding assembly provided by this utility model is as follows:

[0054] 1) Powder Filling: Weigh the entire sheath assembly and record the data. Fill the sheath assembly with powder through the powder injection hole 51 on the sheath end cap. After the initial filling, use a tapping device to evenly tap the outer wall of the sheath assembly to further compact the powder. Stop tapping when the powder is filled again under tapping. Weigh the sheath assembly with powder again and calculate the actual powder weight. If it meets the required powder weight for the casing, stop filling; if not, increase the tapping frequency and continue filling until the estimated powder weight is reached.

[0055] 2) Degassing and Hot Isostatic Pressing Process: After powder loading, the sheath assembly undergoes high-temperature degassing treatment, followed by the hot isostatic pressing process. During the hot isostatic pressing process, the rigid sheath (composed of an outer control sheath 1, an inner control sheath 2, and a sheath cover 3) uses materials with high plasticity, which can maintain shape stability and prevent deformation under high temperature and high pressure. In contrast, the flexible sheath (powder injection sheath 4 and sheath end cap 5) uses materials with relatively low plasticity, which will deform under high temperature and high pressure. This causes the powder inside the flexible sheath to flow towards the rigid sheath area, ultimately achieving densification of the powder inside the rigid sheath.

[0056] 3) Sheath removal: First, most of the rigid sheath is removed by turning and the inner surface contour is machined out. Then, the remaining sheath components are completely removed by chemical etching to obtain the target casing.

[0057] 4) Result verification: The completed casing was scanned and inspected using a 3D scanning device. Comparative analysis revealed that the forming accuracy of the non-machined parts on the outer surface of the casing was controlled within ±0.5mm, which fully meets the requirements for normal use.

[0058] The above description is merely a specific embodiment of this utility model, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this utility model.

[0059] It should be understood that this utility model is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of this utility model is limited only by the appended claims.

Claims

1. A cladding assembly for near-net-shape hot isostatic pressing of thin-walled casings, characterized in that, include: The outer control type sleeve (1) has an irregular groove on its inner surface that corresponds to the irregular protrusion on the outer surface of the target casing; The inner control type sleeve (2) is coaxially nested inside the outer control type sleeve (1); The top cover (3) is used to connect the upper ends of the outer control type sleeve (1) and the inner control type sleeve (2); The powder injection sleeve (4) is connected to the control chamber formed by the outer control sleeve (1) and the inner control sleeve (2) through the sleeve cover (3); The end cap (5) seals the upper end of the powder injection sleeve (4); Among them, the outer control type sleeve (1), the inner control type sleeve (2) and the sleeve cover (3) are fixedly connected to form a rigid sleeve that matches the target casing; the powder injection sleeve (4) and the sleeve end cover (5) are fixedly connected to form a retractable flexible sleeve, and the flexible sleeve is set at the sleeve cover (3), together constituting an overall sleeve assembly.

2. The cladding assembly for near-net-shape hot isostatic pressing of a thin-walled casing according to claim 1, characterized in that, The outer diameter of the external control type sleeve (1) is 1.2 to 1.4 times the maximum outer diameter of the target casing, and the inner diameter matches the outer surface size of the target casing.

3. The cladding assembly for near-net-shape hot isostatic pressing of a thin-walled casing according to claim 1, characterized in that, The outer diameter of the inner control type sleeve (2) is the same as the inner diameter of the target casing, and the inner diameter is 0.6 to 0.8 times the minimum inner diameter of the target casing.

4. The cladding assembly for near-net-shape hot isostatic pressing of a thin-walled casing according to claim 1, characterized in that, The upper and lower end faces of the outer control type sleeve (1) and the upper and lower end faces of the inner control type sleeve (2) are all machined with a semi-V-shaped annular bevel.

5. The cladding assembly for near-net-shape hot isostatic pressing of a thin-walled casing according to claim 4, characterized in that, The bevel angle of the semi-V-shaped annular bevel is 40° to 60°, and the bevel depth is 4mm to 6mm.

6. The cladding assembly for near-net-shape hot isostatic pressing of a thin-walled casing according to claim 4, characterized in that, The cover (3) of the sleeve is an annular structure with a thickness of 4mm to 6mm, and the inner and outer diameters are respectively provided with semi-V-shaped annular bevels that match the outer control type sleeve (1) and the inner control type sleeve (2).

7. The cladding assembly for near-net-shape hot isostatic pressing of a thin-walled casing according to claim 6, characterized in that, The cover (3) of the sleeve is evenly provided with 4 to 8 through holes (31) along the annular structure, and the powder injection sleeve (4) is connected to the through holes (31).

8. The cladding assembly for near-net-shape hot isostatic pressing of a thin-walled casing according to claim 7, characterized in that, The powder injection sleeve (4) is a hollow stepped structure with a wall thickness of 4mm to 6mm and a total length of 100mm to 120mm. The lower half (41) of the powder injection sleeve (4) has a length of 20mm to 30mm, and its outer diameter matches the through hole (31) arranged on the upper cover (3) of the sleeve; the inner diameter of the upper half (42) of the powder injection sleeve (4) is larger than the outer diameter of the lower half (41).

9. The cladding assembly for near-net-shape hot isostatic pressing of a thin-walled casing according to claim 1, characterized in that, The end cap (5) is a circular plate with a wall thickness of 4mm to 6mm, and a powder injection hole (51) with a diameter of 15mm to 20mm is provided in the center; the outer diameter of the end cap (5) and the inner diameter of the powder injection sleeve (4) have a tolerance of ±0.5mm, and a sealed structure is formed after welding.

10. The cladding assembly for near-net-shape hot isostatic pressing of a thin-walled casing according to any one of claims 1 to 9, characterized in that, The outer control type sleeve (1), the inner control type sleeve (2) and the sleeve cover (3) are made of medium and high carbon steel; the powder injection sleeve (4) and the sleeve end cover (5) are made of low carbon steel.

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