Net size and shape collaborative manufacturing method for special-shaped curved surface inner runner of engine

Abstract

The invention relates to a net size shape collaborative manufacturing method of an engine special-shaped curved surface inner runner, which comprises the following steps: carrying out parting design according to a theoretical design molded surface of an engine special-shaped curved surface runner structure to obtain an upper parting and a lower parting of the runner; the upper parting part and the lower parting part of the runner are unfolded to form a net-size flat plate with a plurality of plane grid units; carrying out hot press molding numerical analysis to obtain node displacement of unit nodes in the plane grid units under hot press molding; mapping a reconstructed molded surface of the engine special-shaped curved surface runner structure based on unit nodes in the plane grid units and node displacement inverse conversion, judging a molded surface error between the reconstructed molded surface and a theoretically designed molded surface, and outputting a net-size flat plate if the molded surface error meets a preset requirement; carrying out hot press molding on the flat plate test piece by adopting a net size molding mold to obtain a corresponding runner structure; and the upper flow channel structure and the lower flow channel structure are welded to complete net size shape collaborative manufacturing of the engine special-shaped curved surface flow channel structure.

Description

Technical Field

[0001] The 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 irregular 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 manufactured special-shaped curved surface runner structure meet the requirements of structural shape, runner profile and dimensional accuracy, and then meet the working characteristics of the engine, is the key to engine manufacturing technology. For the expandable special-shaped curved surface runner structure, a hot pressing forming process can be used for preparation. However, during the hot pressing forming process, due to the plastic deformation of the metal material at high temperature, and the uncontrollable thermal deformation of the mold and the 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] In the traditional hot press forming manufacturing process, the forming mold needs to be repaired many times, the size of the forming specimen needs to be adjusted many times, and trial-produced to make the shape, surface and size of the internal flow channel structure after high temperature pressing consistent with or close to the target design value. In order to reduce the number of mold repairs, size adjustments and trial-produced times, and make the internal flow channel structure after hot press forming meet the design requirements, this paper proposes a deployable net size and shape collaborative manufacturing method for engine special-shaped curved flow channel structure. 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 irregular curved inner flow channel.

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

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

[0007] S2. Using a meshing method, the upper parting of the flow channel and the lower parting of the flow channel are respectively unfolded into a net-size flat plate having a plurality of plane mesh units;

[0008] S3. Based on the numerical analysis of hot pressing forming of the unfolded net-size flat plate, the node displacement of the unit node in the plane grid unit under hot pressing forming is obtained; wherein the net-size flat plate includes: a net-size flat plate for parting on the runner and a net-size flat plate for parting on the runner;

[0009] S4. mapping out a reconstructed surface of the engine profiled curved flow channel structure based on the unit nodes in the plane grid unit and the inverse transformation of the node displacement, and determining a surface error between the reconstructed surface and the theoretical design surface, and if the surface error meets a preset requirement, outputting the net-size flat plate as a flat plate specimen for hot-pressing the engine profiled curved flow channel structure;

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

[0011] S6. Welding the upper flow channel structure and the lower flow channel structure to complete the coordinated manufacturing of the net size and shape 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 using a grid division method to respectively unfold the flow channel upper parting and the flow channel lower parting into a net-size flat plate having a plurality of plane grid units includes:

[0013] S21. Discretize the parting on the flow channel 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 take 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 flow channel to complete the conversion of the parting on the flow channel to the parting net size flat plate on the flow channel;

[0014] S22. Discretize the parting under 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, and the center point of the symmetrical position as the expansion base point, and expand it according to the arc length of the parting under the runner to complete the conversion of the parting under the runner to the flat plate with the net size of the parting under the runner.

[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 plane grid units by using a grid division method, the parting grid units of the runner upper parting and the plane grid units of the runner upper parting net-size flat plate, and the parting grid units of the runner lower parting and the plane grid units of the runner lower parting net-size flat plate all satisfy:

[0016] N i =M i K i

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

[0018] According to one aspect of the present invention, in step S3, based on the numerical analysis of hot pressing forming 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 forming, the node displacement is expressed as:

[0019] K eq (q)Δq i =ΔP i

[0020]

[0021] q i =∑Δq i

[0022] Among them, Δq i , ΔP i is the node displacement step and load of the i-th step, 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 Calculated node displacements of the flat mesh elements 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 out the reconstructed profile of the engine profiled curved flow channel structure based on the unit nodes in the plane grid unit and the node displacement inverse transformation 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 unit, u i Indicates the node coordinates of the unit node in the plane grid unit before the change, x i and 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 type grid unit, which is expressed as:

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

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

[0030] S43. Based on the obtained new fracturing grid unit, a reconstructed profile of the engine's special-shaped 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 node 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 profiled 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 disposed in the upper concave mold portion, and the first cooling channel is disposed adjacent to a 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 arranged adjacent to the second pressing surface of the lower convex mold part;

[0041] The first pressing surface and the second pressing 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. Heating the flat specimen to a first temperature and keeping it warm for a first preset time;

[0044] S52. moving the flat specimen 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 corresponding pressing temperature and lower than the deformation damage load of the flat specimen;

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

[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 50-80 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 scheme 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 the hot pressing mold design and the parameter control of the hot pressing forming, which effectively ensures the accuracy of the entire shape manufacturing process.

[0051] According to one solution of the present invention, the inner flow channel with a special-shaped curved surface and the flat plate are converted and mapped to obtain a numerical simulation method for a net-size formed flat plate through grid unit analysis of hot pressing, 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 fully in 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 scheme 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 scheme of the present invention, the present invention can be effectively applied to thick wall structures such as single-layer, interlayer or multi-layer with cooling channels of the engine; the material is suitable for aluminum alloy, 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 flowchart schematically showing a method for collaborative manufacturing of net size and shape according to an embodiment of the present invention;

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

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

[0058] Figure 4is a diagram schematically showing the 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 is a schematic diagram showing a hot pressing process of a flat specimen by a net-size forming die according to an embodiment of the present invention;

[0060] Figure 6 FIG. 4 is a diagram schematically showing the installation position of the second cooling channel according to an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0062] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "lateral", "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 and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element 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 in conjunction with the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not therefore limited to the following embodiments.

[0064] Combination 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 profiled curved surface inner flow channel of the present invention comprises the following steps:

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

[0066] S2. Using a meshing method, the upper runner parting and the lower runner parting are unfolded into a net-size flat plate having a plurality of plane mesh units;

[0067] S3. Based on the numerical analysis of hot pressing forming of the unfolded net-size flat plate, the node displacement of the unit node in the plane grid unit under hot pressing forming is obtained; wherein the net-size flat plate includes: the net-size flat plate of the upper parting of the runner and the net-size flat plate of the lower parting of the runner;

[0068] S4. Mapping out the reconstructed surface of the engine's profiled curved flow channel structure based on the inverse transformation of the unit nodes and node displacements in the plane grid unit, 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 a net size as a flat plate specimen for hot pressing of the engine's profiled curved flow channel structure;

[0069] S5. hot pressing the flat specimen using a net size forming mold to obtain a corresponding flow channel structure, wherein the flow channel structure includes: an upper flow channel structure corresponding to the flow channel upper parting net size flat plate and a lower flow channel structure corresponding to the flow channel lower parting net size flat plate;

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

[0071] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to an embodiment of the present invention, in step S1, the theoretical design profile of the engine profiled curved surface flow channel structure is obtained and a parting design is performed to obtain an upper parting and a lower parting of the flow channel. The engine profiled curved surface flow channel structure may adopt a typical profiled surface inner flow channel structure. Further, combined with the analysis of the hollow shape sticking molding characteristics of the engine profiled curved surface flow channel structure, an upper and lower parting design of the engine profiled curved surface flow channel structure is performed to obtain the corresponding upper parting and lower parting of the flow channel.

[0072] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to an embodiment of the present invention, in step S2, the step of using a grid division method to respectively unfold the flow channel upper parting and the flow channel lower parting into a net-size flat plate having a plurality of plane grid units includes:

[0073] S21. Discretize the parting on the flow channel 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 take 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 flow channel to complete the conversion of the parting on the flow channel to the parting net size flat plate on the flow channel; in this embodiment, the triangular grid method is used to discretize the parting on the flow channel 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 take 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 inner flow channel of the special-shaped surface to the flat plate.

[0074] S22. Discretize the parting under 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 parting under the runner to complete the conversion from the parting under the runner to the flat plate with the net size of the parting under the runner; in this embodiment, the method of converting the parting under the runner into the flat plate with the net size of the parting under the runner is consistent with the aforementioned method, wherein the parting under the runner is discretized into a number of parting grid units by using a triangular grid method, 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 inside the special-shaped surface to the flat plate.

[0075] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to an embodiment of the present invention, in step S2, in the step of using a grid division method to respectively unfold the upper parting of the runner and the lower parting of the runner into a net-size flat plate having a plurality of plane grid units, the parting grid units of the upper parting of the runner and the plane grid units of the net-size flat plate of the upper parting of the runner, and the parting grid units of the lower parting of the runner and the plane grid units of the net-size flat plate of the lower parting of the runner all satisfy:

[0076] N i =M i K i

[0077] Among them, M i represents the grid unit, K i represents the coordinate transformation matrix, N i It 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 parting on the runner and the parting under the runner.

[0078] Combination 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, 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 structural plastic deformation during the high-temperature hot pressing process is mainly considered.

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

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

[0081] K eq (q)Δq i =ΔP i

[0082] In the formula, Δq i , ΔP i is the node displacement step and load of the i-th step, 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] Among them, Δq i , ΔP i is the node displacement step and load of the i-th step, 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 geometric matrix of the cell, q i Calculated node displacements of the flat mesh elements in the net-size flat plate under hot pressing.

[0092] In this embodiment, the net size plate includes: an upper parting net size plate of the runner and a lower parting net size plate of the runner; wherein, the process of carrying out numerical analysis of hot pressing forming on the upper parting net size plate of the runner and the lower parting net size plate of the runner is the same, therefore, the above steps can be respectively performed for the numerical analysis process of the upper parting net size plate of the runner and the lower parting net size plate of the runner, so as to obtain the corresponding node displacements respectively.

[0093] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to an embodiment of the present invention, in step S4, the step of mapping the reconstructed profile of the engine profiled 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 unit is constructed based on the unit nodes and node displacements in the plane mesh unit, 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 unit N' i Nodal coordinates of the unit nodes, u i Represents the plane grid unit N before the change i Nodal coordinates of the unit nodes, x i and 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 type grid unit, which is expressed as:

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

[0099] Among them, M' i represents the new classification 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, so as 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] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, according to an embodiment 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 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 unit nodes in the .

[0105] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, according to one embodiment 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 profiled curved flow channel structure, the area of ​​the net-size flat plate increases after pressing, while the thickness direction of the net-size flat plate will decrease to a certain extent. According to the changes in the unit nodes of the net-size flat plate before and after pressing, the increase in the area of ​​the net-size flat plate after hot pressing can be calculated as ΔA. Since the density change of the plastic deformation of the metal material is small, based on the plastic volume invariance condition of the pressing, the reduction amount Δt in the thickness direction of the net-size flat plate 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] Combination 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 molding mold to obtain a corresponding flow channel structure, the net-size molding 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 molding 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, the contact surface between the net size forming mold and the flat specimen adopts a cooling design. Specifically, a first cooling channel is provided in the upper concave mold part, and the first cooling channel is 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 adjacent to the second compression surface in the lower convex mold part. Therefore, the net size forming mold and the flat specimen can be fully contacted during the forming process through the first cooling channel and the second cooling channel to achieve a uniform cooling effect, thereby reducing the residual stress of the flow channel structure in the special-shaped surface after forming.

[0113] In this embodiment, both the first pressing surface and the second pressing surface are provided with a hardened coating layer; wherein the thickness of the hardened coating layer 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 mold 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] Combination Figure 1 , Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown, according to an embodiment of the present invention, in step S5, in the step of hot pressing the flat specimen using a net size forming mold 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; wherein, 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 is reduced, and the stiffness of the flat specimen is reduced, 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 the springback amount of the flat specimen after pressing remains basically unchanged, which is convenient for 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 therein, it should be understood that they can be implemented by adopting general devices and general methods available in the art.

[0122] The above is only one solution of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

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

2. The net size and shape collaborative manufacturing method according to claim 1, characterized in that: In step S2, the step of using a grid division method to respectively unfold the flow channel upper parting and the flow channel lower parting into a net-size flat plate having a plurality of plane grid units includes: S21. Discretize the parting on the flow channel 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 take 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 flow channel to complete the conversion of the parting on the flow channel to the parting net size flat plate on the flow channel; S22. Discretize the parting under 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, and the center point of the symmetrical position as the expansion base point, and expand it according to the arc length of the parting under the runner to complete the conversion of the parting under the runner to the flat plate with the net size of the parting under the runner.

3. The net size and shape collaborative manufacturing method according to claim 2, characterized in that: 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 plane grid units by using a grid division method, the parting grid units of the runner upper parting and the plane grid units of the runner upper parting net-size flat plate, and the parting grid units of the runner lower parting and the plane grid units of the runner lower parting net-size flat plate all satisfy the following conditions: N i =M i K i Among them, M i represents the grid unit, K i represents the coordinate transformation matrix, N i Represents a plane mesh cell.

4. The net size and shape collaborative manufacturing method according to claim 3 is characterized in that: In step S3, based on the numerical analysis of hot pressing forming 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 forming, the node displacement is expressed as: K eq (q)Δq i =ΔP i q i =∑Δq i Among them, Δq i , ΔP i is the node displacement step and load of the i-th step, 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 Calculated node displacements of the flat mesh elements in the net-size flat plate under hot pressing.

5. The net size and shape collaborative manufacturing method according to claim 4, characterized in that: In step S4, the step of mapping out the reconstructed profile of the engine profiled curved flow channel structure based on the unit nodes in the plane grid unit and the inverse transformation of the node displacements includes: S41. Constructing 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 unit, u i Indicates the node coordinates of the unit node in the plane grid unit before the change, x i and 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 type grid unit, which is expressed as: M' i =N' i K i -1 Among them, M' i represents the new classification grid unit, K i Represents the coordinate transformation matrix, N' i represents a new plane grid cell; S43. Based on the obtained new fracturing grid unit, a reconstructed profile of the engine's special-shaped curved flow channel structure is fitted.

6. The net size and shape 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 requirement, 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: u j =u i (x i ,y i )-q i (Δx i ,Δy i ) Among them, u j Represents the node coordinates of the element nodes in the reconstructed plane mesh element.

7. The net size and shape 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 profiled 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 pressing, A represents the total area of ​​the net-size flat plate before pressing, Δt represents the thickness reduction of the net-size flat plate before and after pressing, and ΔA represents the area increase of the net-size flat plate before and after pressing.

8. The net size and shape collaborative manufacturing method according to claim 7, characterized in that: 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; A first cooling channel is provided in the upper concave mold part, and the first cooling channel is arranged adjacent to the first pressing 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 arranged adjacent to the second pressing surface of the lower convex mold part; The first pressing surface and the second pressing surface are both provided with a hardened coating.

9. The net size and shape 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 mold to obtain a corresponding flow channel structure includes: S51. Heating the flat specimen to a first temperature and keeping it warm for a first preset time; S52. moving the flat specimen 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 corresponding pressing temperature and lower than the deformation damage load of the flat specimen; S53. Maintaining the pressure for a second preset time under the pressure of the net size molding die; 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 and shape collaborative manufacturing method according to claim 9, characterized in that: The thickness of the hardened coating is 50-80 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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