Method for Additive Manufacturing of Lobed Nozzles

Abstract

The present invention discloses a method for additive manufacturing a lobe-shaped nozzle. The method includes: (1) providing alloy powder; (2) forming the alloy powder by laser additive forming, and obtaining a lobe-shaped nozzle blank and a solid support by continuous layer-by-layer stacking, so as to control the shape of the lobe-shaped nozzle blank through the solid support; (3) removing the solid support and performing post-treatment on the lobe-shaped nozzle blank to obtain a lobe-shaped nozzle. The method for additive manufacturing a lobe-shaped nozzle according to the present invention can simplify the manufacturing process, shorten the processing cycle, and improve the final forming accuracy of the product, thereby effectively controlling the afterburner of the engine while reducing the thermal radiation of the aircraft tail nozzle.

Description

Technical Field

[0001] The present invention relates to the field of aerospace, and in particular, to a method for additive manufacturing of a lobe-shaped nozzle. Background Art

[0002] The exhaust temperature of the tail nozzle of a modern aircraft jet engine is about 1000 degrees Celsius, which is the strongest heat radiation source on the aircraft. The fundamental measure to reduce the heat radiation of the tail nozzle is to reduce the exhaust temperature of the engine. For this purpose, an aircraft can adopt a precision lobe-shaped nozzle to increase the contact area between the tail nozzle and cold air, which is conducive to the heat dissipation of the tail nozzle and the mixing of the gas jet and cold air, and reduce the infrared radiation.

[0003] In the traditional process, the lobe-shaped nozzle is formed by welding multiple sheet metal parts and machined parts, and then shaped by a mold and precision machined. However, this process route is complex, the processing cycle is long, and it is difficult to meet the design requirements for the appearance and dimensions of the welded parts. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this reason, an object of the present invention is to provide a method for additive manufacturing of a lobe-shaped nozzle. The method for additive manufacturing of a lobe-shaped nozzle according to the present invention can simplify the manufacturing process, shorten the processing cycle, and improve the final forming accuracy of the product, thereby effectively controlling the afterburner of the engine while reducing the heat radiation of the aircraft tail nozzle.

[0005] In one aspect of the present invention, a method for additive manufacturing of a lobe-shaped nozzle is provided. According to an embodiment of the present invention, the method includes:

[0006] (1) Providing alloy powder;

[0007] (2) Using a laser additive forming method to form the alloy powder, and obtaining a lobe-shaped nozzle blank and a solid support by continuously stacking layer by layer, so as to control the shape of the lobe-shaped nozzle blank through the solid support;

[0008] (3) Removing the solid support and performing post-treatment on the lobe-shaped nozzle blank to obtain a lobe-shaped nozzle.

[0009] According to the method for additive manufacturing of a lobe-shaped nozzle in the above embodiments of the present invention, by using the laser additive forming method to form the alloy powder, and utilizing selective laser melting (SLM), the laser melts the alloy powder layer by layer according to a pre-planned scanning path trajectory. Through continuous stacking of layer upon layer, a lobe-shaped nozzle blank and a solid support are directly obtained, which not only reduces the processes of welding and die alignment, shortens the processing cycle, but also reduces the cost. In addition, by controlling the shape of the lobe-shaped nozzle blank through the solid support, then removing the solid support, and performing post-treatment on the lobe-shaped nozzle blank, a lobe-shaped nozzle is obtained, which can control the thin-wall deformation during the 3D printing process, improve the final forming accuracy of the product, and further reduce the thermal radiation of the aircraft tail nozzle while effectively controlling the afterburner of the engine. Thus, the method for additive manufacturing of a lobe-shaped nozzle of the present invention can simplify the manufacturing process, shorten the processing cycle, and improve the final forming accuracy of the product, and further reduce the thermal radiation of the aircraft tail nozzle while effectively controlling the afterburner of the engine.

[0010] In addition, the method for additive manufacturing of a lobe-shaped nozzle in the above embodiments of the present invention may further have the following additional technical features:

[0011] In some embodiments of the present invention, by mass percentage, the alloy powder includes: C 0 to 0.10%, Cr 20.00% to 23.00%, Co 0 to 1.00%, Mo 8.00% to 10.00%, Al 0 to 0.40%, Ti 0 to 0.40%, S 0 to 0.15%, Cu 0 to 0.070%, Fe 0 to 5.00%, Nb 3.15% to 4.15%, Si 0 to 0.50%, Mn 0 to 0.50%, P 0 to 0.015%, N 0 to 0.04%, H 0 to 0.05%, O 0 to 0.05%, and the balance is Ni. Thus, the thermal radiation of the aircraft tail nozzle can be reduced while effectively controlling the afterburner of the engine.

[0012] In some embodiments of the present invention, the layer thickness of each layer is not greater than 60 μm. Thus, the final forming accuracy of the product can be improved, and further the thermal radiation of the aircraft tail nozzle can be reduced while effectively controlling the afterburner of the engine.

[0013] In some embodiments of the present invention, the laser power of the laser additive forming method is 360 W to 400 W, the laser scanning speed is 900 mm / s to 1200 mm / s, and the laser scanning spot size is 83 μm to 90 μm. Thus, the final forming accuracy of the product can be improved, and further the thermal radiation of the aircraft tail nozzle can be reduced while effectively controlling the afterburner of the engine.

[0014] In some embodiments of the present invention, the solid support includes a support test bar located inside the trough of the lobe-shaped nozzle blank. Thereby, the final forming accuracy of the product can be improved, and thus the heat radiation of the aircraft tail nozzle can be reduced while effectively controlling the afterburner of the engine.

[0015] In some embodiments of the present invention, the solid support includes a support plate located between two adjacent peaks of the lobe-shaped nozzle blank. Thereby, the final forming accuracy of the product can be improved, and thus the heat radiation of the aircraft tail nozzle can be reduced while effectively controlling the afterburner of the engine.

[0016] In some embodiments of the present invention, in step (1), the alloy powder is prepared by gas atomization.

[0017] In some embodiments of the present invention, in step (1), the average particle size of the alloy powder is 30 μm to 40 μm. Thereby, the final forming accuracy of the product can be improved, and thus the heat radiation of the aircraft tail nozzle can be reduced while effectively controlling the afterburner of the engine.

[0018] In some embodiments of the present invention, in step (3), the post-treatment includes heat treatment and finishing. Thereby, the final forming accuracy of the product can be improved, and thus the heat radiation of the aircraft tail nozzle can be reduced while effectively controlling the afterburner of the engine.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 is a schematic flow chart of a method for additive manufacturing of a lobe-shaped nozzle according to an embodiment of the present invention;

[0022] Figure 2 is a schematic structural diagram of a lobe-shaped nozzle blank according to an embodiment of the present invention;

[0023] Figure 3 is a polished microstructure diagram of a lobe-shaped nozzle according to Embodiment 1 of the present invention;

[0024] Figure 4 is an etched microstructure diagram of a lobe-shaped nozzle according to Embodiment 1 of the present invention;

[0025] Figure 5 is a polished microstructure diagram of a lobe-shaped nozzle according to Embodiment 2 of the present invention;

[0026] Figure 6It is the corrosion state microstructure diagram of the lobe nozzle according to Embodiment 2 of the present invention. Detailed implementation manners

[0027] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0028] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

[0029] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0030] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is less than that of the second feature.

[0032] In one aspect of the present invention, there is provided a method for additive manufacturing of a lobe-shaped nozzle. According to an embodiment of the present invention, with reference to Figure 1 , the method comprises:

[0033] S100: Providing alloy powder

[0034] In this step, by providing alloy powder, a lobe-shaped nozzle blank 10 and a solid support 20 can be obtained subsequently (for reference Figure 2 for understanding). Thus, the final forming accuracy of the product can be improved, and further, while effectively controlling the afterburner of the engine, the thermal radiation of the aircraft tail nozzle can be reduced.

[0035] According to an embodiment of the present invention, by mass percentage, the above alloy powder comprises: C 0 - 0.10%, Cr 20.00% - 23.00%, Co 0 - 1.00%, Mo 8.00% - 10.00%, Al 0 - 0.40%, Ti 0 - 0.40%, S 0 - 0.15%, Cu 0 - 0.070%, Fe 0 - 5.00%, Nb 3.15% - 4.15%, Si 0 - 0.50%, Mn 0 - 0.50%, P 0 - 0.015%, N 0 - 0.04%, H 0 - 0.05%, O 0 - 0.05%, and the balance is Ni. Thus, it can be ensured that the impurity content is relatively low during the subsequent laser additive forming process, thereby improving the final forming accuracy of the product, and further reducing the thermal radiation of the aircraft tail nozzle while effectively controlling the afterburner of the engine.

[0036] According to an embodiment of the present invention, the average particle size D50 of the above-mentioned alloy powder is 30 μm to 40 μm. The inventor found that if the particle size of the alloy powder is too large, incomplete fusion will occur, and the surface of the lobe-shaped nozzle blank obtained by subsequent forming will be relatively rough, and there will be pore defects in the product metallography; if the particle size of the alloy powder is too small, the fluidity will be poor, the powder spreading effect will be poor, and the quality of the product obtained subsequently will be poor. By controlling the particle size of the above-mentioned alloy powder in the present invention, on the one hand, complete fusion can be ensured, avoiding pore defects in the product metallography, and on the other hand, the fluidity and powder spreading effect of the alloy powder can be improved, thereby improving the product quality. Further, D10 of the alloy powder ≥ 15 μm, D90 ≤ 53 μm, thus, it is beneficial to further improve the product quality.

[0037] According to an embodiment of the present invention, the method for preparing the above-mentioned alloy powder is not particularly limited, and those skilled in the art can select according to actual needs. As a preferred solution, the above-mentioned alloy powder can be prepared by gas atomization.

[0038] S200: Form the alloy powder by using laser additive manufacturing

[0039] In this step, the alloy powder is formed by using laser additive manufacturing. Selective laser melting is used, and the laser melts the alloy powder layer by layer according to a pre-planned scanning path trajectory. By continuously stacking layer by layer, the lobe-shaped nozzle blank 10 and the solid support 20 are directly obtained (for reference Figure 2 understanding), which not only reduces the processes of splicing welding and die shape correction, shortens the processing cycle, but also reduces the cost; in addition, by controlling the shape of the lobe-shaped nozzle blank 10 through the solid support 20, the thin-wall deformation during the 3D printing process can be controlled, the final forming accuracy of the product can be improved, and thus the heat radiation of the aircraft tail nozzle can be reduced while effectively controlling the afterburner of the engine. It should be noted that in order to ensure the product quality, before forming the alloy powder, the inventor simulated and calculated the laser additive model scheme, measured the deformation amount after shape control during the additive process, and optimized the laser additive scheme by simulation calculation until the deformation amount requirement was met.

[0040] According to an embodiment of the present invention, the layer thickness of each layer is not greater than 60 μm. The inventor found that if the layer thickness is too large, the surface of the lobe-shaped nozzle blank obtained will be relatively rough. By controlling the layer thickness of each layer in the present invention, the printing effect of the surface of the lobe-shaped nozzle blank can be improved, thereby improving the final forming accuracy of the product, and thus reducing the heat radiation of the aircraft tail nozzle while effectively controlling the afterburner of the engine.

[0041] According to an embodiment of the present invention, the laser power of the laser additive manufacturing method is 360W to 400W, the laser scanning speed is 900mm / s to 1200mm / s, and the laser scanning spot size is 83μm to 90μm. The inventor found that if the laser scanning spot is too large, the laser is not concentrated and the power is small; if the laser scanning spot is too small, the laser is concentrated and the power is large; if the laser power is too large or the scanning rate is too small, the product is prone to warping; if the laser power is too small or the scanning rate is too large, it will cause incomplete penetration and defects. In the present invention, by controlling the process parameters of laser additive manufacturing, the final forming accuracy of the product can be improved, thereby effectively controlling the afterburner of the engine while reducing the thermal radiation of the aircraft tail nozzle.

[0042] According to an embodiment of the present invention, referring to Figure 2 , the solid support 20 includes a support test bar 21 located inside the trough of the lobe-shaped nozzle blank 10. Thus, during the continuous stacking process of layer by layer, the support test bar 21 as a solid support can prevent the trough of the lobe-shaped nozzle blank 10 from deforming, which further helps to improve the final forming accuracy of the product, thereby effectively controlling the afterburner of the engine while reducing the thermal radiation of the aircraft tail nozzle. Further, the support test bar 21 can be connected to the trough of the lobe-shaped nozzle blank 10 through a connecting plate 211. Thus, it is beneficial to remove the support test bar 21 subsequently. It should be noted that the connecting plate 211 can be a solid plate or a hollow plate, preferably a hollow plate.

[0043] According to an embodiment of the present invention, referring to Figure 2 , the solid support 20 includes a support plate 22 located between two adjacent peaks of the lobe-shaped nozzle blank 10. Thus, during the continuous stacking process of layer by layer, the support plate 22 as a solid support can prevent the peaks of the lobe-shaped nozzle blank 10 from deforming, which further helps to improve the final forming accuracy of the product, thereby effectively controlling the afterburner of the engine while reducing the thermal radiation of the aircraft tail nozzle. Further, both sides of the support plate 22 are respectively connected to the upper middle parts of two adjacent peaks. Thus, it is convenient to remove the support plate 22 subsequently. The shape of the support plate 22 is not particularly limited as long as it can achieve the purpose of preventing the peaks of the lobe-shaped nozzle blank 10 from deforming. Those skilled in the art can select according to needs. As a preferred solution, the support plate 22 can be in a dovetail shape, which further helps to remove the support plate 22 subsequently. It should be noted that the support plate 22 can be a solid plate or a hollow plate, preferably a hollow plate.

[0044] S300: Remove the solid support and perform post-treatment on the lobe-shaped nozzle blank

[0045] In this step, by removing the solid support 20 and performing post-treatment on the lobe-shaped nozzle blank 10, a lobe-shaped nozzle can be obtained, which can further improve the final forming accuracy of the product, and thus reduce the thermal radiation of the aircraft tail nozzle while effectively controlling the afterburner of the engine. It should be noted that the method for removing the solid support 20 is not particularly limited. For example, the solid support 20 can be removed by wire cutting or laser cutting.

[0046] According to an embodiment of the present invention, the above post-treatment includes heat treatment and finish machining. Thereby, the final forming accuracy of the product can be further improved, and the thermal radiation of the aircraft tail nozzle can be reduced while effectively controlling the afterburner of the engine. The specific heat treatment and finish machining methods are not particularly limited as long as they can achieve the purpose of improving the final forming accuracy of the product. Those skilled in the art can select according to actual needs. As a preferred solution, the heat treatment method is as follows: After the part to be processed is taken out of the cabin, heat treatment should be carried out within 72 hours. After loading the part to be processed into the heat treatment furnace, the vacuum in the furnace chamber of the heat treatment furnace is pumped to less than 6.67×10 -2 Pa and then start heating to 500°C ± 10°C (the heating rate is not greater than 100°C / h), and keep warm for 30 min; continue heating to 1100°C ± 10°C (the heating rate is not greater than 150°C / h), keep warm for 0.5 h, and keep the vacuum degree not exceeding 6.67×10 -2 Pa; Cool with 2Bar argon + blower to 80°C and then take out of the furnace and air-cool to room temperature. Considering the subsequent assembly relationship of the nozzle, machining allowances are left for the interfaces with assembly relationships during additive manufacturing, and numerical control finish machining is carried out after heat treatment.

[0047] Therefore, by using the method for additive manufacturing of a lobe-shaped nozzle of the present invention, the manufacturing process can be simplified, the processing cycle can be shortened, and the final forming accuracy of the product can be improved, and thus the thermal radiation of the aircraft tail nozzle can be reduced while effectively controlling the afterburner of the engine.

[0048] Next, the present invention will be described with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0049] Example 1

[0050] The alloy powder is formed by laser additive manufacturing method. Through continuous layer-by-layer stacking, a lobe-shaped nozzle blank, a solid support, and a furnace test bar are obtained. By mass percentage, the alloy powder includes: C 0.10%, Cr 20.00%, Co 1.00%, Mo 8.00%, Al 0.40%, Ti 0.40%, S 0.15%, Cu 0.070%, Fe 5.00%, Nb 3.15%, Si 0.50%, Mn 0.50%, P 0.015%, N 0.04%, H 0.05%, O 0.05%, and the balance is Ni. The average particle size of the alloy powder is 40μm, D10 is 16μm, D90 is 53μm, and the laser additive manufacturing conditions are a layer thickness of 60μm, a laser power of 375W, a laser scanning speed of 1100mm / s, and a laser scanning spot of 85μm. Then, the solid support is removed, and the lobe-shaped nozzle blank is post-treated to obtain a lobe-shaped nozzle.

[0051] Example 2

[0052] The alloy powder is formed by laser additive manufacturing method. Through continuous layer-by-layer stacking, a lobe-shaped nozzle blank, a solid support, and a furnace test bar are obtained. By mass percentage, the alloy powder includes: C 0.10%, Cr 23.00%, Co 0.80%, Mo 10.00%, Al 0.35%, Ti 0.30%, S 0.10%, Cu 0.065%, Fe 4.00%, Nb 4.15%, Si 0.40%, Mn 0.45%, P 0.010%, N 0.04%, H 0.03%, O 0.05%, and the balance is Ni. The average particle size of the alloy powder is 30μm, D10 is 15μm, D90 is 51μm, and the laser additive manufacturing conditions are a layer thickness of 60μm, a laser power of 375W, a laser scanning speed of 1100mm / s, and a laser scanning spot of 85μm. Then, the solid support is removed, and the lobe-shaped nozzle blank is post-treated to obtain a lobe-shaped nozzle.

[0053] The mechanical properties of the furnace test bars obtained in Examples 1-2 are tested according to the standard GB / T228.1-2010 (Metallic materials - Tensile testing - Part 1: Method of test at room temperature), and the test results are shown in Table 1.

[0054] Table 1

[0055]

[0056] The dimensions of the lobe-shaped nozzles obtained in Examples 1-2 are measured with a vernier caliper, and the measurement results are shown in Table 2:

[0057] Table 2

[0058]

[0059] The as-cast test bars obtained in Examples 1-2 were subjected to microstructural analysis. The microstructural diagram of the as-cast test bar obtained in Example 1 is as shown in Figures 3-4 shown, and the microstructural diagram of the as-cast test bar obtained in Example 2 is as shown in Figures 5-6 shown.

[0060] As can be seen from Table 1-2 and Figures 3-6 it can be seen that the products obtained by the method for additive manufacturing of lobe-shaped nozzles of the present invention have excellent mechanical properties, high final forming accuracy, no cracks, no strip segregation defects, and no obvious hole defects in the microstructure, and can thus reduce the thermal radiation of the aircraft tail nozzle while effectively controlling the afterburner of the engine.

[0061] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0062] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for additive manufacturing of a lobe-shaped nozzle, characterized in that, Including: (1) Providing alloy powder; (2) Using a laser additive manufacturing method to form the alloy powder, and obtaining a lobe-shaped nozzle blank and a solid support by continuous layer-by-layer stacking, so as to control the shape of the lobe-shaped nozzle blank through the solid support; (3) Removing the solid support and performing post-treatment on the lobe-shaped nozzle blank to obtain a lobe-shaped nozzle; By mass percentage, the alloy powder includes: C 0 to 0.10%, Cr 20.00% to 23.00%, Co 0 to 1.00%, Mo 8.00% to 10.00%, Al 0 to 0.40%, Ti 0 to 0.40%, S 0 to 0.15%, Cu 0 to 0.070%, Fe 0 to 5.00%, Nb 3.15% to 4.15%, Si 0 to 0.50%, Mn 0 to 0.50%, P 0 to 0.015%, N 0 to 0.04%, H 0 to 0.05%, O 0 to 0.05%, and the balance is Ni; The layer thickness of each layer is not greater than 60 μm; The laser power of the laser additive manufacturing method is 360 W to 400 W, the laser scanning speed is 900 mm / s to 1200 mm / s, and the laser scanning spot size is 83 μm to 90 μm; The solid support includes a support furnace test bar located inside the wave trough of the lobe-shaped nozzle blank, and the support furnace test bar is connected to the wave trough of the lobe-shaped nozzle blank through a connecting plate; The solid support includes a support plate located between two adjacent wave peaks of the lobe-shaped nozzle blank, and both sides of the support plate are respectively connected to the upper middle parts of the two adjacent wave peaks; In step (1), the average particle size of the alloy powder is 30 μm to 40 μm.

2. The method according to claim 1, characterized in that, In step (1), the alloy powder is prepared by gas atomization.

3. The method according to claim 1, characterized in that, In step (3), the post-treatment includes heat treatment and finish machining.

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