A method for collaborative manufacturing of net size and shape of inner flow passages on special-shaped surfaces of engines

Abstract

The present invention relates to a method for collaboratively manufacturing the net size and form of a flow channel on a special-shaped curved surface of an engine. The method comprises: carrying out parting design according to a theoretical design surface of a flow channel structure on the special-shaped curved surface of the engine to obtain an upper parting and a lower parting of the flow channel; respectively unfolding the upper parting and the lower parting of the flow channel into a net size flat plate having a plurality of plane grid units; carrying out numerical analysis of hot pressing to obtain the node displacement of unit nodes in the plane grid units under hot pressing; mapping a reconstructed surface of the flow channel structure on the special-shaped curved surface of the engine based on an inverse conversion of the unit nodes and the node displacements in the plane grid units, judging a surface error between the reconstructed surface and the theoretical design surface, and outputting a net size flat plate if the surface error meets a preset requirement; hot pressing a flat plate specimen using a net size forming die to obtain a corresponding flow channel structure; and welding the upper flow channel structure and the lower flow channel structure to complete the collaborative manufacturing of the net size and form of the flow channel structure on the special-shaped curved surface of the engine.

Description

Technical Field

[0001] The present invention relates to the field of aerospace, and in particular to a method for collaboratively manufacturing the net size and shape of an engine's irregularly curved inner flow channel. Background Art

[0002] The special-shaped curved surface runner structure is a common internal runner structure form of the engine. How to make the special-shaped curved surface runner structure after manufacture meet the requirements of structural shape, runner surface and dimensional accuracy, and thus meet the working characteristics of the engine, is the key to engine manufacturing technology. For expandable special-shaped curved surface runner structures, hot pressing forming process can be used for preparation. However, during the hot pressing forming process, due to the plastic deformation of metal materials at high temperatures, and the uncontrollable thermal deformation of the mold and workpiece during the high-temperature hot pressing forming process, the shape, surface and size of the runner structure after hot pressing forming deviate from the theoretical design runner structure. Therefore, how to reduce the deviation in the hot pressing process is the key to the hot forming preparation of special-shaped curved surface runner structures.

[0003] The traditional hot press forming process requires multiple mold modifications, dimensional adjustments, and trial production to ensure that the shape, surface, and dimensions of the internal flow channel structure after hot press forming are consistent or close to the target design values. To reduce the number of these mold modifications, dimensional adjustments, and trial production cycles and ensure that the internal flow channel structure after hot press forming meets the design requirements, this paper proposes a deployable net dimension and shape-property collaborative manufacturing method for engine special-shaped curved flow channel structures. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for collaboratively manufacturing the net size and shape of an engine's irregularly curved inner flow channel.

[0005] To achieve the above-mentioned object, the present invention provides a method for collaboratively manufacturing the net size and shape of an engine's irregularly curved inner flow channel, comprising the following steps:

[0006] S1. Conduct parting design based on the theoretical design profile of the engine's profiled curved flow channel structure to obtain its upper and lower flow channel partings;

[0007] S2. Using a meshing method, the upper and lower runner partings are expanded into a flat plate having a net size of several planar grid units;

[0008] S3. Based on the numerical analysis of hot pressing of the unfolded net-size flat plate, the node displacements of the unit nodes in the plane mesh unit under hot pressing are obtained; wherein the net-size flat plate includes: a net-size flat plate for the upper parting of the runner and a net-size flat plate for the lower parting of the runner;

[0009] S4. Mapping a reconstructed surface of the engine's deformed curved flow channel structure based on the unit nodes in the planar grid cells and the inverse transformation of the node displacements, and determining a surface error between the reconstructed surface and the theoretical design surface. If the surface error meets a preset requirement, outputting the net-size flat plate as a flat plate specimen for hot-pressing the engine's deformed curved flow channel structure;

[0010] S5. hot-pressing the flat specimen using a net-size forming die to obtain a corresponding runner structure, wherein the runner structure includes: an upper runner structure corresponding to the runner upper parting net-size flat plate and a lower runner structure corresponding to the runner lower parting net-size flat plate;

[0011] S6. Welding the upper flow channel structure and the lower flow channel structure to complete the net size and shape collaborative manufacturing of the engine's special-shaped curved flow channel structure.

[0012] According to one aspect of the present invention, in step S2, the step of respectively unfolding the runner upper parting and the runner lower parting into a net-size flat plate having a plurality of planar grid units using a grid division method includes:

[0013] S21. Discretize the runner parting into a plurality of parting grid units. Take the parting grid unit at the middle symmetrical position of one end as the reference grid, and the center point of the symmetrical position as the expansion base point. Expand the parting grid according to the arc length of the runner parting to complete the conversion of the runner parting to the runner parting net size flat plate.

[0014] S22. Discretize the lower runner parting into a number of parting grid units, take the parting grid unit at the middle symmetrical position of one end as the reference grid, and the center point of the symmetrical position as the expansion base point, and expand it according to the arc length of the lower runner parting to complete the conversion of the lower runner parting to the lower runner parting net size flat plate.

[0015] According to one aspect of the present invention, in step S2, in the step of respectively unfolding the runner upper parting and the runner lower parting into a net-size flat plate having a plurality of planar grid units using a grid division method, the following conditions are satisfied between the parting grid units of the runner upper parting and the planar grid units of the runner upper parting net-size flat plate, and between the parting grid units of the runner lower parting and the planar grid units of the runner lower parting net-size flat plate:

[0016] N i =M i K i

[0017] Among them, M i represents the fractal grid unit, K i Represents the coordinate transformation matrix, N iRepresents a plane grid cell.

[0018] According to one aspect of the present invention, in step S3, based on the numerical analysis of hot pressing of the unfolded net-size flat plate, in the step of obtaining the node displacement of the unit node in the plane grid unit under hot pressing, the node displacement is expressed as:

[0019] K eq (q)Δq i =ΔP i

[0020]

[0021] q i =∑Δq i

[0022] Where Δq i , ΔP i is the node displacement step and load of step i, K eq (q) is the element stiffness matrix, D eq (q) is the elastic-plastic matrix of the material, B is the geometric matrix of the element, and B T is the transpose of the unit's geometry matrix, q i is the calculated nodal displacement of the flat mesh element in the net-size flat plate under hot pressing.

[0023] According to one aspect of the present invention, in step S4, the step of mapping the reconstructed profile of the engine's profiled curved flow channel structure based on the unit nodes in the plane grid unit and the inverse transformation of the node displacements includes:

[0024] S41. Construct a new plane mesh unit based on the unit nodes and node displacements in the plane mesh unit, which is expressed as:

[0025] u' i =u i (x i ,y i )+q i (Δx i ,Δy i )

[0026] Among them, u' i represents the node coordinates of the unit node in the new plane mesh element, u i Indicates the node coordinates of the unit node in the plane grid unit before the change, x i and y i Indicates the node coordinate value of the unit node in the plane grid unit before the change, Δx i and Δy i represents the node displacement q iThe coordinate change value of

[0027] S42. Based on the coordinate transformation matrix, the unit nodes in the new plane grid unit are inversely transformed to obtain a new fractal grid unit, which is expressed as:

[0028] M' i =N' i K i -1

[0029] Among them, M' i Represents the new fractal grid unit, K i Represents the coordinate transformation matrix, N' i represents a new plane grid cell;

[0030] S43. Based on the obtained new fractal grid unit, a reconstructed surface of the engine's irregular curved flow channel structure is fitted.

[0031] According to one aspect of the present invention, in step S4, in the step of determining the profile error between the reconstructed profile and the theoretical design profile, if the profile error does not meet the preset requirements, a reconstructed plane mesh unit under reverse node displacement is constructed based on the unit nodes and node displacements in the plane mesh unit, and steps S3 to S4 are re-executed based on the reconstructed plane mesh unit; wherein the reconstructed plane mesh unit is represented as:

[0032] u j =u i (x i ,y i )-q i (Δx i ,Δy i )

[0033] Among them, u j Represents the nodal coordinates of the element nodes in the reconstructed plane mesh element.

[0034] According to one aspect of the present invention, in step S4, in the step of outputting the net-size flat plate as a flat plate specimen for hot-pressing the engine's special-shaped curved flow channel structure, the thickness of the net-size flat plate is determined to complete the output of the net-size flat plate, wherein the thickness of the net-size flat plate is expressed as:

[0035] t'=t+Δt

[0036]

[0037] Among them, t' represents the thickness of the output net-size flat plate, t represents the thickness of the net-size flat plate before profiling, A represents the total area of ​​the net-size flat plate before profiling, Δt represents the thickness reduction of the net-size flat plate before and after profiling, and ΔA represents the area increase of the net-size flat plate before and after profiling.

[0038] According to one aspect of the present invention, in step S5, in the step of hot pressing the flat specimen using a net-size forming mold to obtain a corresponding flow channel structure, the net-size forming mold includes: an upper concave mold part and a lower convex mold part;

[0039] A first cooling channel is provided in the upper concave mold portion, and the first cooling channel is provided adjacent to the first pressing surface in the upper concave mold portion;

[0040] A second cooling channel is provided in the lower convex mold part, and the second cooling channel is provided adjacent to the second pressing surface of the lower convex mold part;

[0041] The first press-profile surface and the second press-profile surface are both provided with a hardened coating.

[0042] According to one aspect of the present invention, in step S5, the step of hot pressing the flat specimen using a net-size forming mold to obtain a corresponding flow channel structure includes:

[0043] S51. The flat specimen is heated to a first temperature and kept warm for a first preset time;

[0044] S52. The flat specimen is moved into the net-size forming die for loading and pressing, wherein the hot forming load on the flat specimen is higher than the yield strength of the flat specimen at the pressing temperature and lower than the deformation damage load of the flat specimen;

[0045] S53. Maintaining pressure for a second preset time under the pressure of the net size molding mold;

[0046] S54. Cooling liquid is simultaneously introduced into the first cooling channel and the second cooling channel on the net size forming mold until the flat plate specimen is cooled to a preset temperature, and then the formed flat plate specimen is removed.

[0047] According to one aspect of the present invention, the thickness of the hardened coating is 50 to 80 μm, and the hardened coating is a NiW coating or a chromium coating;

[0048] The first temperature is 850° C. to 1050° C., and the first preset time is 5 to 10 minutes;

[0049] The second preset time length is 5 to 10 minutes.

[0050] According to one solution of the present invention, the present invention fully covers the net size shape collaborative manufacturing process route of the inner flow channel of the special-shaped surface, the net size forming plate and hot pressing mold design, and the parameter control of hot pressing forming, effectively ensuring the accuracy of the entire shape manufacturing process.

[0051] According to one solution of the present invention, the mutual conversion and mapping of the inner flow channel with a special-shaped curved surface and the flat plate is adopted, and a numerical simulation method of the net-size formed flat plate is obtained through the grid unit analysis of hot pressing forming, which has the characteristics of fast iteration and the like.

[0052] According to one solution of the present invention, by designing a cooling channel on the die pressing surface, the die surface is in full contact with the profiled inner flow channel structure surface and is evenly cooled, thereby effectively reducing the residual stress after hot pressing of the profiled inner flow channel structure.

[0053] According to one solution of the present invention, the present invention can effectively reduce the number of mold repairs, size adjustments of hot-pressed flat parts and trial production of runner structures, so that the shape, surface and dimensional accuracy of the internal runner structure after hot-pressing meet the design requirements, thereby realizing the coordinated manufacturing of the net size and shape of the special-shaped curved surface runner structure.

[0054] According to one solution of the present invention, the present invention can be effectively applied to thick-walled structures such as single-layer, sandwich or multi-layer structures with cooling channels of engines; the materials are applicable to aluminum alloys, austenitic stainless steel, some nickel-based high-temperature alloys, etc., which effectively improves the applicability of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is a block diagram schematically showing steps of a net size form collaborative manufacturing method according to one embodiment of the present invention;

[0056] Figure 2 is a flow chart schematically illustrating a net size form collaborative manufacturing method according to one embodiment of the present invention;

[0057] Figure 3 1 is a process flow diagram schematically illustrating a method for collaborative manufacturing of net-size and shape properties according to an embodiment of the present invention, wherein (a) represents a theoretical design profile of an engine profiled curved flow channel structure, (b) represents a parting design result of the theoretical design profile, (c) represents a net-size flat plate with the upper and lower partings of the flow channel respectively unfolded, (d) represents hot pressing of a flat plate specimen by a net-size forming mold, (e) represents the upper and lower flow channel structures formed by hot pressing, and (f) represents an engine profiled curved flow channel structure formed by splicing the upper and lower flow channel structures;

[0058] Figure 4is a diagram schematically showing the mutual conversion between the runner upper parting or runner lower parting and the unfolded net size flat plate according to one embodiment of the present invention;

[0059] Figure 5 Schematically illustrates a hot press forming process of a flat specimen using a net-size forming die according to one embodiment of the present invention;

[0060] Figure 6 FIG. 1 is a diagram schematically showing the installation position of the second cooling channel according to an embodiment of the present invention. DETAILED DESCRIPTION

[0061] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0062] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or positional relationship shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0063] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not limited to the following embodiments.

[0064] Combine Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, a method for collaboratively manufacturing the net size and shape of an engine's irregularly curved inner flow channel of the present invention includes the following steps:

[0065] S1. Conduct parting design based on the theoretical design profile of the engine's profiled curved flow channel structure to obtain its upper and lower flow channel partings;

[0066] S2. Using a meshing method, the upper and lower runner partings are unfolded into a flat plate with a net size of several planar mesh units;

[0067] S3. Based on the numerical analysis of hot pressing of the unfolded net-size flat plate, the node displacements of the unit nodes in the plane mesh element under hot pressing are obtained. The net-size flat plate includes: the net-size flat plate with the upper parting of the runner and the net-size flat plate with the lower parting of the runner;

[0068] S4. Mapping a reconstructed surface of the engine's contoured flow channel structure based on the inverse transformation of the unit nodes and node displacements in the plane mesh elements, and determining the surface error between the reconstructed surface and the theoretical design surface. If the surface error meets the preset requirements, outputting a flat plate with the net dimensions as a flat plate specimen for hot pressing the engine's contoured flow channel structure;

[0069] S5. Hot pressing the flat specimen using a net-size forming die to obtain a corresponding runner structure, wherein the runner structure includes: an upper runner structure corresponding to the runner upper parting net-size flat plate and a lower runner structure corresponding to the runner lower parting net-size flat plate;

[0070] S6. Weld the upper flow channel structure and the lower flow channel structure to complete the net size and shape collaborative manufacturing of the engine's special-shaped curved flow channel structure.

[0071] Combine Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, in step S1, the theoretical design surface of the engine's special-shaped curved surface flow channel structure is obtained and a parting design is performed to obtain its upper flow channel parting and lower flow channel parting. The engine's special-shaped curved surface flow channel structure can adopt a typical special-shaped surface inner flow channel structure. Further, combined with the analysis of the hollow shape sticking molding characteristics of the engine's special-shaped curved surface flow channel structure, the upper and lower parting designs of the engine's special-shaped curved surface flow channel structure are performed to obtain the corresponding upper flow channel parting and lower flow channel parting.

[0072] Combine Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, in step S2, the step of respectively unfolding the runner upper parting and the runner lower parting into a net-size flat plate having a plurality of planar grid units using a grid division method includes:

[0073] S21. Discretize the parting on the runner into several parting grid units, take the parting grid unit at the middle symmetrical position of one end as the reference grid, and the center point of the symmetrical position as the expansion base point, and expand it according to the arc length of the parting on the runner to complete the conversion of the parting on the runner to the net size flat plate of the parting on the runner; in this embodiment, the triangular grid method is used to discretize the parting on the runner into several parting grid units, take the parting grid unit at the middle symmetrical position of one end as the reference grid, and the center point O of the symmetrical position as the expansion base point ( Figure 3 ), unfold the surface according to the arc length to realize the conversion of the flow channel inside the special-shaped surface to the flat plate.

[0074] S22. Discretize the lower parting of the runner into a number of parting grid units, take the parting grid unit at the middle symmetrical position of one end as the reference grid, take the center point of the symmetrical position as the expansion base point, and expand it according to the arc length of the lower parting of the runner to complete the conversion from the lower parting of the runner to the flat plate with the net size of the lower parting of the runner; in this embodiment, the method of converting the lower parting of the runner into the flat plate with the net size of the lower parting of the runner is consistent with the above method, wherein the triangular grid method is used to discretize the lower parting of the runner into a number of parting grid units, take the parting grid unit at the middle symmetrical position of one end as the reference grid, take the center point of the symmetrical position as the expansion base point, and expand the surface according to the arc length to realize the conversion of the runner in the special-shaped surface to the flat plate.

[0075] Combine Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, in step S2, in the step of respectively unfolding the upper runner parting and the lower runner parting into a net-size flat plate having a plurality of plane grid units using a grid division method, the following conditions are satisfied between the parting grid units of the upper runner parting and the plane grid units of the upper runner parting net-size flat plate, and between the parting grid units of the lower runner parting and the plane grid units of the lower runner parting net-size flat plate:

[0076] N i =M i K i

[0077] Among them, M i represents the fractal grid unit, K i Represents the coordinate transformation matrix, N i Represents a plane grid unit, and the subscript i represents the serial number of the parting grid unit and the plane grid unit, and its value can be set according to the upper parting and lower parting of the runner.

[0078] Combine Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, during the hot pressing process, since the yield strength of the metal material is significantly reduced at high temperature, the pressing load of the high-temperature hot pressing is higher than the yield limit value of the material, and the plastic deformation of the flat plate accounts for the main part during the forming process. The rebound deformation during the pressing process can be ignored, and the main consideration is the structural plastic deformation during the high-temperature hot pressing.

[0079] To this end, in step S3, based on the numerical analysis of hot pressing of the unfolded net-size flat plate, the step of obtaining the node displacement of the unit node in the plane mesh unit under hot pressing includes:

[0080] Based on the finite element analysis method of the full quantity theory, the hot pressing load is loaded proportionally, and the compression load ΔP of a certain grid unit node on the net size plate is calculated. i Displacement Δq under action i .

[0081] K eq (q)Δq i =ΔP i

[0082] Where Δq i , ΔP i is the node displacement step and load of step i, K eq (q) is the element stiffness matrix and is expressed as:

[0083]

[0084] Where D eq (q) is the elastic-plastic matrix of the material, B is the geometric matrix of the element, and B T Represents the transpose of the geometry matrix of the cell.

[0085] According to the loading history of the load, the node displacement of the unit node in a plane grid unit of the net size plate under hot pressing can be calculated as q i , and is expressed as:

[0086] q i =∑Δq i .

[0087] Therefore, the node displacement can be summarized as:

[0088] K eq (q)Δq i =ΔP i

[0089]

[0090] q i =∑Δq i

[0091] Where Δq i , ΔP i is the node displacement step and load of step i, K eq (q) is the element stiffness matrix, D eq (q) is the elastic-plastic matrix of the material, B is the geometric matrix of the element, and B Trepresents the transpose of the unit's geometry matrix, q i is the calculated nodal displacement of the flat mesh element in the net-size flat plate under hot pressing.

[0092] In this embodiment, the net size plate includes: a runner upper parting net size plate and a runner lower parting net size plate; wherein, the process of performing numerical analysis of hot pressing forming on the runner upper parting net size plate and the runner lower parting net size plate is the same. Therefore, the above steps can be performed separately for the numerical analysis process of the runner upper parting net size plate and the runner lower parting net size plate, and the corresponding node displacements can be obtained respectively.

[0093] Combine Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, in step S4, the step of mapping the reconstructed surface of the engine's irregular curved flow channel structure based on the inverse transformation of the unit nodes and node displacements in the plane grid unit includes:

[0094] S41. A new plane mesh element is constructed based on the unit nodes and node displacements in the plane mesh element, which is expressed as:

[0095] u' i =u i (x i ,y i )+q i (Δx i ,Δy i )

[0096] Among them, u' i Represents the new plane grid cell N' i Nodal coordinates of the unit node, u i Represents the plane grid unit N before the change i Nodal coordinates of the middle element node, x i and y i Indicates the node coordinate value of the unit node in the plane grid unit before the change, Δx i and Δy i represents the node displacement q i The coordinate change value of

[0097] S42. Based on the coordinate transformation matrix, the unit nodes in the new plane grid unit are inversely transformed to obtain a new fractal grid unit, which is expressed as:

[0098] M' i =N' i K i -1

[0099] Among them, M' i Represents the new fractal grid unit, K i Represents the coordinate transformation matrix, N' i represents a new plane grid cell;

[0100] S43. Based on the obtained new fractal grid units, a reconstructed surface of the engine's irregular curved flow channel structure is fitted.

[0101] Furthermore, the surface error between the reconstructed surface and the theoretical design surface is determined. If the surface error meets the preset requirements, the net-size flat plate is output as a flat plate specimen for hot pressing of the engine's special-shaped curved surface flow channel structure, to be used for subsequent hot pressing trial production of the special-shaped curved surface inner flow channel structure; wherein the preset requirement is the critical value δ of the surface error.

[0102] Combine Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, in step S4, in the step of determining the surface error between the reconstructed surface and the theoretical design surface, if the surface error does not meet the preset requirements, a reconstructed plane mesh unit under reverse node displacement is constructed based on the unit nodes and node displacements in the plane mesh unit, and steps S3 to S4 are re-executed based on the reconstructed plane mesh unit; wherein the reverse node displacement is expressed as -q i , then the corresponding reconstructed plane grid unit is expressed as:

[0103] u j =u i (x i ,y i )-q i (Δx i ,Δy i )

[0104] Among them, u j Represents the reconstructed plane grid unit N j Nodal coordinates of the element nodes in the element.

[0105] Combine Figure 1 、 Figure 2 、 Figure 3 and Figure 4As shown, according to one embodiment of the present invention, in step S4, when outputting a clear-size flat plate as a flat plate specimen for hot-pressing an engine's profiled curved flow channel structure, the area of ​​the clear-size flat plate increases after pressing, while the thickness of the clear-size flat plate decreases to a certain extent. Based on the changes in the unit nodes of the clear-size flat plate before and after pressing, the increase in the area of ​​the clear-size flat plate after hot-pressing can be calculated as ΔA. Since the density change of metal materials during plastic deformation is small, based on the condition of constant plastic volume during pressing, the reduction in the thickness of the clear-size flat plate Δt can be calculated and expressed as:

[0106]

[0107] Therefore, the thickness of the net size plate is determined to complete the output process of the net size plate. The thickness of the net size plate is expressed as:

[0108] t'=t+Δt

[0109]

[0110] Among them, t' represents the thickness of the output net-size flat plate, t represents the thickness of the net-size flat plate before profiling, A represents the total area of ​​the net-size flat plate before profiling, Δt represents the thickness reduction of the net-size flat plate before and after profiling, and ΔA represents the area increase of the net-size flat plate before and after profiling.

[0111] Combine Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 and Figure 6 As shown, according to one embodiment of the present invention, in step S5, in the step of hot pressing the flat specimen with a net-size forming mold to obtain the corresponding flow channel structure, the net-size forming mold includes: an upper concave mold part and a lower convex mold part; wherein, in order to ensure that the surface dimensions of the flat specimen after high-temperature pressing, cooling shrinkage, and unloading are consistent with the design values, the surfaces of the upper concave mold part and the lower convex mold part of the forming mold are respectively designed to correspond to the inner surface or outer surface of the flow channel inside the engine's special-shaped curved surface.

[0112] In order to ensure the rigidity of the net-size forming mold and reduce the heat transfer effect of the workpiece on the upper concave mold part and the lower convex mold part, which causes the mold to heat up and cause the workpiece to deform due to compression, a cooling design is adopted for the contact surface between the net-size forming mold and the flat specimen. Specifically, a first cooling channel is provided in the upper concave mold part, and the first cooling channel is provided adjacent to the first compression surface in the upper concave mold part; a second cooling channel is provided in the lower convex mold part, and the second cooling channel is provided adjacent to the second compression surface in the lower convex mold part. Thus, the first cooling channel and the second cooling channel can achieve full contact between the net-size forming mold and the flat specimen during the forming process to achieve a uniform cooling effect, thereby reducing the residual stress of the flow channel structure in the special-shaped curved surface after forming.

[0113] In this embodiment, both the first pressing surface and the second pressing surface are provided with a hardened coating; wherein the thickness of the hardened coating is 50-80 μm.

[0114] In this embodiment, the hardened coating is a NiW coating or a chromium coating, which effectively improves the surface hardness and wear resistance of the pressing die, and facilitates multiple and repeated pressing.

[0115] Through the above arrangement, the durability and surface stability of the net size forming die of the present invention are effectively guaranteed, which is beneficial to ensuring high-precision forming of the workpiece.

[0116] Combine Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 and Figure 6 As shown, according to one embodiment of the present invention, in step S5, in the step of hot pressing the flat specimen using a net-size forming die to obtain the corresponding flow channel structure, the hot pressing forming temperature is generally higher than the recrystallization temperature of the metal material, so that the internal flow channel structure after forming has no obvious work hardening phenomenon and its springback is greatly reduced; to this end, it includes:

[0117] S51. Heat the flat specimen to a first temperature and keep it warm for a first preset time. In order to minimize the rebound of the workpiece or even eliminate it, the first temperature at which the flat specimen is heated is 850°C to 1050°C, and the first preset time is 5 to 10 minutes. At this temperature and preset time, the elastic modulus of the metal material decreases, and the stiffness of the flat specimen decreases, which facilitates hot pressing.

[0118] S52. Move the flat specimen into the net-size forming mold for loading and pressing, wherein an air compressor is used to achieve slow loading and pressing of the net-size forming mold. Specifically, the hot forming load on the flat specimen is higher than the yield strength of the flat specimen at the corresponding pressing temperature and is lower than the deformation damage load of the flat specimen.

[0119] S53. Maintain the pressure for a second preset time under the pressing action of the net size forming mold; wherein the second preset time is 5 to 10 minutes, thereby keeping the rebound amount of the flat specimen after pressing substantially unchanged, facilitating net size pressing.

[0120] S54. Cooling liquid is simultaneously introduced into the first cooling channel and the second cooling channel on the net size forming mold until the flat plate specimen is cooled to a preset temperature and then the formed flat plate specimen is removed.

[0121] The above contents are merely examples of specific solutions of the present invention. For devices and structures not described in detail, it should be understood that they can be implemented by adopting general devices and methods available in the art.

[0122] The above description is merely one embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for collaboratively manufacturing the net size and shape of an engine's irregularly curved inner flow channel, characterized in that: The following steps are involved: S1. Conduct parting design based on the theoretical design profile of the engine's profiled curved flow channel structure to obtain its upper and lower flow channel partings; S2. Using a meshing method, the upper and lower runner partings are expanded into a flat plate having a net size of several planar grid units; S3. Based on the numerical analysis of hot pressing of the unfolded net-size flat plate, the node displacements of the unit nodes in the plane mesh unit under hot pressing are obtained; wherein the net-size flat plate includes: a net-size flat plate for the upper parting of the runner and a net-size flat plate for the lower parting of the runner; S4. Mapping a reconstructed surface of the engine's deformed curved flow channel structure based on the unit nodes in the planar grid cells and the inverse transformation of the node displacements, and determining a surface error between the reconstructed surface and the theoretical design surface. If the surface error meets a preset requirement, outputting the net-size flat plate as a flat plate specimen for hot-pressing the engine's deformed curved flow channel structure; S5. hot-pressing the flat specimen using a net-size forming die to obtain a corresponding runner structure, wherein the runner structure includes: an upper runner structure corresponding to the runner upper parting net-size flat plate and a lower runner structure corresponding to the runner lower parting net-size flat plate; S6. Welding the upper flow channel structure and the lower flow channel structure to complete the net size and shape collaborative manufacturing of the engine's special-shaped curved flow channel structure.

2. The net size form collaborative manufacturing method according to claim 1, characterized in that: In step S2, the step of respectively unfolding the upper runner parting and the lower runner parting into a net-size flat plate having a plurality of planar grid units using a grid division method includes: S21. Discretize the runner parting into a plurality of parting grid units. Take the parting grid unit at the middle symmetrical position of one end as the reference grid, and the center point of the symmetrical position as the expansion base point. Expand the parting grid according to the arc length of the runner parting to complete the conversion of the runner parting to the runner parting net size flat plate. S22. Discretize the lower runner parting into a number of parting grid units, take the parting grid unit at the middle symmetrical position of one end as the reference grid, and the center point of the symmetrical position as the expansion base point, and expand it according to the arc length of the lower runner parting to complete the conversion of the lower runner parting to the lower runner parting net size flat plate.

3. The net size form collaborative manufacturing method according to claim 2, characterized in that: In step S2, in the step of respectively unfolding the upper runner parting and the lower runner parting into a net-size flat plate having a plurality of planar grid units using a grid division method, the following conditions are satisfied between the parting grid units of the upper runner parting and the planar grid units of the upper runner parting net-size flat plate, and between the parting grid units of the lower runner parting and the planar grid units of the lower runner parting net-size flat plate: N i =M i K i Among them, M i represents the fractal grid unit, K i Represents the coordinate transformation matrix, N i Represents a plane grid cell.

4. The net size form collaborative manufacturing method according to claim 3, characterized in that: In step S3, based on the numerical analysis of hot pressing of the unfolded net-size flat plate, the node displacement of the unit node in the plane grid unit under hot pressing is obtained. The node displacement is expressed as: K eq (q)Δq i =ΔP i q i =∑Δq i Where Δq i , ΔP i is the node displacement step and load of step i, K eq (q) is the element stiffness matrix, D eq (q) is the elastic-plastic matrix of the material, B is the geometric matrix of the element, and B T is the transpose of the unit's geometry matrix, q i is the calculated nodal displacement of the flat mesh element in the net-size flat plate under hot pressing.

5. The net size form collaborative manufacturing method according to claim 4, characterized in that: In step S4, the step of mapping out the reconstructed profile of the engine's irregular curved flow channel structure based on the unit nodes in the plane grid unit and the inverse transformation of the node displacements includes: S41. Construct a new plane mesh unit based on the unit nodes and node displacements in the plane mesh unit, which is expressed as: u' i =u i (x i ,y i )+q i (Δx i ,Δy i ) Among them, u' i represents the node coordinates of the unit node in the new plane mesh element, u i Indicates the node coordinates of the unit node in the plane grid unit before the change, x i and y i Indicates the node coordinate value of the unit node in the plane grid unit before the change, Δx i and Δy i represents the node displacement q i The coordinate change value of S42. Based on the coordinate transformation matrix, the unit nodes in the new plane grid unit are inversely transformed to obtain a new fractal grid unit, which is expressed as: M' i =N' i K i -1 Among them, M' i Represents the new fractal grid unit, K i Represents the coordinate transformation matrix, N' i represents a new plane grid cell; S43. Based on the obtained new fractal grid unit, a reconstructed surface of the engine's irregular curved flow channel structure is fitted.

6. The net size form collaborative manufacturing method according to claim 5, characterized in that: In step S4, in the step of determining the profile error between the reconstructed profile and the theoretical design profile, if the profile error does not meet the preset requirements, a reconstructed plane mesh unit under reverse node displacement is constructed based on the unit nodes and node displacements in the plane mesh unit, and steps S3 to S4 are re-executed based on the reconstructed plane mesh unit; wherein the reconstructed plane mesh unit is represented by: u j =u i (x i ,y i )-q i (Δx i ,Δy i ) Among them, u j Represents the nodal coordinates of the element nodes in the reconstructed plane mesh element.

7. The net size form collaborative manufacturing method according to claim 6, characterized in that: In step S4, in the step of outputting the net-size flat plate as a flat plate specimen for hot-pressing the engine's special-shaped curved flow channel structure, the thickness of the net-size flat plate is determined to complete the output of the net-size flat plate, wherein the thickness of the net-size flat plate is expressed as: t'=t+Δt Among them, t' represents the thickness of the output net-size flat plate, t represents the thickness of the net-size flat plate before profiling, A represents the total area of ​​the net-size flat plate before profiling, Δt represents the thickness reduction of the net-size flat plate before and after profiling, and ΔA represents the area increase of the net-size flat plate before and after profiling.

8. The net size and shape collaborative manufacturing method according to claim 7, characterized in that: In step S5, the flat specimen is hot-pressed to obtain a corresponding flow channel structure using a net-size forming mold, wherein the net-size forming mold includes an upper concave mold portion and a lower convex mold portion; A first cooling channel is provided in the upper concave mold portion, and the first cooling channel is provided adjacent to the first pressing surface in the upper concave mold portion; A second cooling channel is provided in the lower convex mold part, and the second cooling channel is provided adjacent to the second pressing surface of the lower convex mold part; The first press-profile surface and the second press-profile surface are both provided with a hardened coating.

9. The net size form collaborative manufacturing method according to claim 8, characterized in that: In step S5, the step of hot pressing the flat specimen using a net-size forming die to obtain a corresponding flow channel structure includes: S51. The flat specimen is heated to a first temperature and kept warm for a first preset time; S52. The flat specimen is moved into the net-size forming die for loading and pressing, wherein the hot forming load on the flat specimen is higher than the yield strength of the flat specimen at the pressing temperature and lower than the deformation damage load of the flat specimen; S53. Maintaining pressure for a second preset time under the pressure of the net size molding mold; S54. Cooling liquid is simultaneously introduced into the first cooling channel and the second cooling channel on the net size forming mold until the flat plate specimen is cooled to a preset temperature, and then the formed flat plate specimen is removed.

10. The net size form collaborative manufacturing method according to claim 9, characterized in that: The thickness of the hardened coating is 50 to 80 μm, and the hardened coating is a NiW coating or a chromium coating; The first temperature is 850°C to 1050°C, and the first preset time is 5 to 10 minutes; The second preset time length is 5 to 10 minutes.

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