Lower surface forming method for nickel-based superalloy component with different-angle suspension areas

Abstract

A lower surface forming method for nickel-based superalloy components in different-angle suspension areas comprises the following steps that a component model is obtained and sliced, and a plurality of slice models are obtained; dividing each slice model into an unsupported overhang area and an entity area; selective laser melting forming parameters of the unsupported suspension area and the solid area are set; based on the selective laser melting forming parameters of the support-free overhanging area, the laser remelting frequency of the support-free overhanging area is determined; the nickel-based alloy powder is laid layer by layer, forming of a solid area is conducted through a selective laser melting device, then forming and repeated remelting of a support-free overhanging area are conducted in sequence till the selective laser melting device completes laser melting forming of all layers of nickel-based alloy powder, and therefore the nickel-based alloy support-free component is obtained. By means of the method, the nearly-fully-compact nickel-based alloy unsupported component with the lower breadth roughness Sa smaller than 20 microns, the density higher than 99% and the buckling deformation degree lower than 100 microns can be obtained.

Description

Technical Field

[0001] This application relates to the field of laser additive manufacturing technology, specifically to a method for forming the lower surface of components with different angles of overhang in nickel-based superalloys. Background Technology

[0002] With the development of science and technology and social production and demand, the demand for rapid manufacturing and high performance of complex structural parts in current precision industrial manufacturing is gradually increasing, which places higher demands on modern additive manufacturing technology. Laser powder bed melting (LPBF) technology is gradually becoming a core means of manufacturing high value-added parts because it can realize the integrated forming of complex geometries, shorten the production cycle and support customized design.

[0003] However, in the laser selective melting (SDM) manufacturing process, areas below 45° require support structures to ensure forming quality. For components with internal channels or complex cavities, these support structures cannot be removed due to their structural characteristics, necessitating low-angle forming. Since the internal cavities and channels lack physical support, severe defects easily occur near the overhanging areas during printing, with scum and warping being the most prominent issues. Severe roughness on the lower surface reduces the normal engineering performance of the internal cavity structure (such as channel heat dissipation), thus seriously affecting service performance. Summary of the Invention

[0004] In view of the above, it is necessary to propose a method for forming the lower surface of nickel-based superalloy components with different angles of overhang, so as to improve the forming accuracy and lower surface roughness of nickel-based superalloy unsupported components without reducing the forming density.

[0005] This application provides a method for forming the lower surface of a nickel-based superalloy component with different angled overhangs, comprising the following steps: Obtain the component model and slice the component model to obtain multiple slice models; Based on multiple slice models, each slice model is divided into an unsupported overhang region and a solid region, wherein the overhang angle of the unsupported overhang region of the component model is 20° to 45°. The laser selective melting forming parameters for the unsupported overhanging region and the laser selective melting forming parameters for the solid region are set, wherein the heat input of the unsupported overhanging region is lower than the heat input of the solid region; Based on the laser selective melting forming parameters of the unsupported overhanging region, the number of laser remelting times for the unsupported overhanging region is determined. Based on the forming parameters of the unsupported overhanging region and the forming parameters of the solid region, nickel-based alloy powder is laid layer by layer. The solid region of each layer of nickel-based alloy powder is first formed by a laser selective melting device. Then, the unsupported overhanging region is formed and remelted multiple times in sequence. This process is repeated until the laser selective melting device completes the laser melting and forming of all layers of nickel-based alloy powder, thereby obtaining a nickel-based alloy unsupported component.

[0006] In some embodiments, the nickel-based alloy powder is composed of the following by mass percentage: Cr content of 20%-24%, W content of 13%-15%, Mo content of 1%-3%, C content of 0.05%-0.2%, Si content of 0.2%-0.5%, Mn content of 0.2%-1%, Co content of 2%-4%, La content of 0.01-0.1%, Fe content of 1%-3%, Al content of less than 1%, Ti content of less than 0.1%, Cu content of less than 0.5%, B content of less than 0.01%, and the balance being Ni element and unavoidable impurities.

[0007] In some embodiments, prior to the step of obtaining the component model and slicing the component model, the method further includes: Nickel-based alloy powder with a particle size of 15μm~53μm was dried in a vacuum-protected drying oven and stored safely for later use. In 3D software, a component model is designed, wherein the overhang angle of the unsupported overhang area of ​​the component model is 20° to 45°.

[0008] In some embodiments, the step of dividing each slice model into an unsupported overhang region and a solid region based on a plurality of slice models specifically includes: Based on multiple slice models, determine the protrusion length and overhang angle of each slice model relative to the adjacent slice models; Based on the protrusion length and the overhang angle, each slice model is divided into the unsupported overhang area and the solid area.

[0009] In some embodiments, the length of the unsupported overhanging area of ​​each layer is twice the protruding length.

[0010] In some embodiments, the steps preceding the layer-by-layer deposition of nickel-based alloy powder include: The dried nickel-based alloy powder is pre-formed in the powder feeding chamber. After the cleaned substrate is placed on the lifting platform of the forming chamber, all the doors are closed. Argon gas is introduced into the forming chamber until the oxygen content is below 100 ppm, and the substrate is preheated to 90°C to 110°C.

[0011] In some embodiments, the laser selective melting forming parameters of the unsupported overhang region include overhang laser power, overhang scanning speed, and overhang scanning spacing. The overhang laser power ranges from 100W to 160W, the overhang scanning speed ranges from 800mm / s to 1500mm / s, and the overhang scanning spacing ranges from 0.07mm to 0.12mm.

[0012] In some embodiments, the laser selective melting forming parameters of the solid region include solid laser power, solid scanning speed and solid scanning spacing. The solid laser power ranges from 185W to 235W, the solid scanning speed ranges from 600mm / s to 1000mm / s, and the solid scanning spacing ranges from 0.07mm to 0.12mm.

[0013] In some embodiments, the laser scanning strategy for the unsupported overhanging area is a whole-area scan, the laser scanning strategy for the solid area is a 67° cross-strip scan, and the thickness of each layer of the nickel-based alloy powder ranges from 0.02 mm to 0.05 mm.

[0014] In some embodiments, the step following the determination of the number of laser remelting cycles for the unsupported overhang region includes: The laser selective melting forming parameters of the multiple slice models, the laser selective melting forming parameters of the unsupported overhanging region, the laser selective melting forming parameters of the solid region, and the number of laser remelting times of the unsupported overhanging region are input into the laser selective melting device to obtain a pre-demonstration nickel-based alloy unsupported component model. Based on the fact that the pre-demonstration nickel-based alloy unsupported component model conforms to the standard, it is confirmed that the laser selective melting forming parameters and the slicing model are correct.

[0015] The aforementioned method for forming the lower surface of nickel-based superalloy components with different angled overhangs involves dividing each slice model into an unsupported overhang region and a solid region. The heat input of the unsupported overhang region is lower than that of the solid region. Furthermore, the unsupported overhang region undergoes multiple remeltings after forming. This region division and low-power multiple remeltings effectively suppress the roughness of the lower surface of the unsupported overhang region, resulting in a nearly fully dense nickel-based alloy unsupported component with a lower surface roughness Sa less than 20 μm, a density higher than 99%, and a warpage less than 100 μm. By using lower forming parameters for the unsupported overhang region, severe melt-through and slag adhesion defects are avoided. Multiple remeltings further reduce the roughness of the lower surface, as slag adhesion and powder adhesion are eliminated. Simultaneously, multiple remeltings effectively improve the density of the overhang region, ensuring the reliability of the overhang component. Furthermore, without the need for a support structure, only the laser selective melting forming parameters need to be adjusted to effectively print nickel-based alloy unsupported components. This method is low-cost and can print various thin components, making it suitable for large-scale production and applications. In addition, it avoids the time and material waste of forming supports during the forming process, as well as the time waste and yield reduction caused by support removal during post-processing, thus improving the efficiency of the production process. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a laser selective melting device adapted for laser additive manufacturing of metal components.

[0017] Figure 2 This is a flowchart of a method for forming the lower surface of a nickel-based superalloy component with a different angle of overhang, as proposed in an embodiment of this application.

[0018] Figure 3 This is a schematic diagram showing the division between the unsupported overhanging region and the solid region of an unsupported nickel-based alloy component.

[0019] Figure 4 yes Figure 2 The flowchart of the method before step S10.

[0020] Figure 5 yes Figure 2 The flowchart of the specific method for step S20 in the process.

[0021] Figure 6 yes Figure 2 The flowchart of the method after step S40.

[0022] Figure 7 These are comparison images of the lower surface quality of Example 1, Comparative Example 1, and Comparative Example 2.

[0023] Figure 8This is a density comparison diagram of the unsupported overhanging regions in Example 1, Comparative Example 1, and Comparative Example 2.

[0024] Figure 9 This is a comparison diagram of the degree of warping deformation in the unsupported overhanging area of ​​Example 1, Comparative Example 1, and Comparative Example 2.

[0025] Figure 10 These are comparison images of the surface quality of the lower part of Example 2 and Comparative Example 3.

[0026] Figure 11 These are density comparison diagrams of the unsupported overhanging regions in Example 2 and Comparative Example 3.

[0027] Figure 12 It is a statistical comparison chart of the forming quality of the lower part and the density of the unsupported overhanging area. Detailed Implementation

[0028] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein 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 only used to explain this application, and should not be construed as limiting this application.

[0029] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0030] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0031] When manufacturing metal components using laser additive manufacturing, please refer to [link / reference]. Figure 1Before forming, the dried metal powder needs to be pre-formed in the powder hopper 10 of the forming chamber 100; then, the substrate 20 is placed on the preheating platform 40 connected to the lifting platform 30 of the forming chamber 100, and all the doors of the forming chamber 100 are closed to ensure the airtightness of the forming chamber 100. 99.99% argon gas is introduced into the forming chamber 100 until the oxygen content is below 100ppm; the upper surface of the substrate 20 is adjusted to be flush with the lower surface of the scraper 50; and the substrate 20 is preheated. During forming, the powder hopper 10 lays metal powder layer by layer on the substrate 20 through the powder feeding channel 60, and the laser 70 shines the laser on the metal powder on the forming plane through the galvanometer 80 to perform laser melting and forming until the laser melting and forming of all layers of metal powder is completed, thereby obtaining a metal component.

[0032] Please see Figure 2 This application proposes a method for forming the lower surface of components with different angles of overhang in nickel-based superalloys, comprising the following steps: S10: Obtain the component model and slice the component model to obtain multiple slice models.

[0033] S20, based on multiple slice models, each slice model is divided into an unsupported overhanging region 101 and a solid region 102 (e.g., Figure 3 As shown in the figure, the overhang angle of the unsupported overhang area of ​​the component model is 20° to 45°.

[0034] S30, set the laser selective melting forming parameters for the unsupported overhanging area and the solid area, wherein the heat input of the unsupported overhanging area is lower than the heat input of the solid area.

[0035] S40, based on the laser selective melting forming parameters of the unsupported overhanging region, determines the number of laser remelting times for the unsupported overhanging region.

[0036] S50, based on the forming parameters of the unsupported overhanging region and the forming parameters of the solid region, nickel-based alloy powder is laid layer by layer, and the solid region of each layer of nickel-based alloy powder is first formed by a laser selective melting device, and then the unsupported overhanging region is formed and remelted multiple times in sequence, and repeated in sequence until the laser selective melting device completes the laser melting and forming of all layers of nickel-based alloy powder, thereby obtaining a nickel-based alloy unsupported component.

[0037] To address the issues of surface roughness and warping caused by heat accumulation in the unsupported overhanging region during the forming process, the first step is to identify the regions of the unsupported nickel-based alloy component and divide it into unsupported overhanging regions and solid regions. By using a low-laser-power multiple remelting forming method for the unsupported overhanging region, the heat accumulation in the unsupported overhanging region can be reduced, thereby achieving good forming of the low-angle unsupported component.

[0038] In particular, since the unsupported overhang area of ​​the nickel-based alloy unsupported component is filled with powder rather than solid material, its heat dissipation capacity is poor, and it is more prone to heat accumulation leading to defects such as melt-through and warping. Therefore, the heat input of the unsupported overhang area is lower than that of the solid area. This reduces the size of the molten pool and avoids severe melt-through and powder adhesion on the lower surface. At the same time, multiple laser remelting processes avoid the problem of insufficient forming density caused by low laser power.

[0039] The laser selective melting device includes a fiber laser, a beam expander, a laser galvanometer, a flat focusing lens, a servo system, and a heating platform; its specific structure will not be described in detail here.

[0040] The aforementioned method for forming the lower surface of nickel-based superalloy components with different angled overhangs involves dividing each slice model into an unsupported overhang region and a solid region. The heat input of the unsupported overhang region is lower than that of the solid region. Furthermore, the unsupported overhang region undergoes multiple remeltings after forming. This region division and low-power multiple remeltings effectively suppress the roughness of the lower surface of the unsupported overhang region, resulting in a nearly fully dense nickel-based alloy unsupported component with a lower surface roughness Sa less than 20 μm, a density higher than 99%, and a warpage less than 100 μm. By using lower forming parameters for the unsupported overhang region, severe melt-through and slag adhesion defects are avoided. Multiple remeltings further reduce the roughness of the lower surface, as slag adhesion and powder adhesion are eliminated. Simultaneously, multiple remeltings effectively improve the density of the overhang region, ensuring the reliability of the overhang component. Furthermore, without the need for a support structure, only the laser selective melting forming parameters need to be adjusted to effectively print nickel-based alloy unsupported components. This method is low-cost and can print various thin components, making it suitable for large-scale production and applications. In addition, it avoids the time and material waste of forming supports during the forming process, as well as the time waste and yield reduction caused by support removal during post-processing, thus improving the efficiency of the production process.

[0041] Furthermore, in this scheme, the laser power used in both the initial forming and subsequent remelting processes is lower than that used in conventional forming processes. This is to avoid generating high heat input to the unsupported overhanging area for a short period of time. By reducing the peak heat input in the overhanging area through multiple remelting processes, the warping deformation and powder agglomeration on the lower surface caused by the large thermal stress in the unsupported overhanging area during forming are effectively reduced. This can effectively avoid warping deformation caused by large heat input and porosity caused by powder element ablation and evaporation.

[0042] In some embodiments, the nickel-based alloy powder is composed of the following by mass percentage: 20%-24% Cr, 13%-15% W, 1%-3% Mo, 0.05%-0.2% C, 0.2%-0.5% Si, 0.2%-1% Mn, 2%-4% Co, 0.01-0.1% La, 1%-3% Fe, less than 1% Al, less than 0.1% Ti, less than 0.5% Cu, less than 0.01% B, with the balance being Ni and unavoidable impurities.

[0043] Preferably, the nickel-based alloy powder has the following composition by mass percentage: 22.13% Cr, 14.55% W, 2.8% Mo, 0.12% C, 0.38% Si, 0.5% Mn, 1.89% Fe, 2.4% Co, 0.43% Al, 0.08% Ti, 0.47% Cu, 0.02% La, 0.015% B, with the balance being Ni and unavoidable impurities.

[0044] Please see Figure 4 In some embodiments, prior to the step of obtaining the component model and slicing the component model, the method further includes: S11. Nickel-based alloy powder with a particle size of 15μm~53μm is dried in a vacuum-protected drying oven and stored safely for later use.

[0045] S12, Design a component model in 3D software, where the overhang angle of the unsupported overhang area of ​​the component model is 20° to 45°.

[0046] Please see Figure 5 In some embodiments, the step of dividing each slice model into unsupported overhanging regions and solid regions based on multiple slice models specifically includes: S21, Based on multiple slice models, determine the protrusion length and overhang angle of each slice model relative to the adjacent slice models; S22, based on the protrusion length and the angle of the overhang area, each slice model is divided into an unsupported overhang area and a solid area. The length of the unsupported overhang area in each layer is twice the protrusion length.

[0047] In some embodiments, the laser selective melting forming parameters for the unsupported overhang region include overhang laser power, overhang scanning speed, and overhang scanning spacing. The overhang laser power ranges from 100W to 160W, the overhang scanning speed ranges from 800mm / s to 1500mm / s, and the overhang scanning spacing ranges from 0.07mm to 0.12mm. The laser scanning strategy for the unsupported overhang region is overall scanning. The laser output beam diameter is 50μm to 120μm.

[0048] In some embodiments, the laser selective melting forming parameters for the solid region include solid laser power, solid scanning speed, and solid scanning spacing. The solid laser power ranges from 185W to 235W, the solid scanning speed ranges from 600mm / s to 1000mm / s, and the solid scanning spacing ranges from 0.07mm to 0.12mm. In some embodiments, the laser scanning strategy for the solid region is a 67° cross-strip scanning.

[0049] Please see Figure 6 In some embodiments, the steps following the determination of the number of laser remelting cycles for the unsupported overhang region include: S41, input multiple slice models, laser selective melting forming parameters of unsupported overhanging areas, laser selective melting forming parameters of solid areas, and laser remelting times of unsupported overhanging areas into the laser selective melting device to obtain a pre-demonstration nickel-based alloy unsupported component model; S42, based on the pre-demonstration of a nickel-based alloy unsupported component model conforming to the standard, confirms that the laser selective melting forming parameters and the slice model are correct.

[0050] In some embodiments, the laser scanning strategy for unsupported overhang areas is a whole-area scan, while the laser scanning strategy for solid areas is a 67° cross-strip scan, and the thickness of each layer of nickel-based alloy powder ranges from 0.02 mm to 0.05 mm.

[0051] In some embodiments, the steps preceding the layer-by-layer deposition of nickel-based alloy powder include: The dried nickel-based alloy powder is pre-formed in the powder feeding chamber. After the cleaned substrate is placed on the lifting platform of the forming chamber, all the doors are closed. Argon gas is introduced into the forming chamber until the oxygen content is below 100 ppm, and the substrate is preheated to 90°C to 110°C.

[0052] Specifically, the surface of the 316L stainless steel substrate is cleaned before forming; the dried nickel-based alloy powder is pre-formed in the powder feeding chamber; the cleaned 316L stainless steel substrate is placed on the lifting platform and all doors are closed to ensure the equipment is airtight; 99.99% argon gas is introduced into the forming chamber until the oxygen content is below 100ppm; the upper surface of the 316L stainless steel substrate is adjusted to be flush with the lower surface of the equipment scraper; the 316L stainless steel substrate is preheated to 90℃~110℃ by resistance heating.

[0053] Preheating the substrate can reduce the temperature gradient in the unsupported overhanging area during the forming process, thereby reducing the thermal stress and warping deformation in the unsupported overhanging area.

[0054] The technical solutions of this application are not limited to the specific embodiments exemplified below, but also include any combination of the specific embodiments.

[0055] Example 1 This embodiment provides a method for forming the lower surface of components with different angled overhangs in nickel-based superalloys, including the following steps: Step 1: Dry the nickel-based alloy powder with a particle size of 15μm~53μm in a vacuum-protected drying oven and store it safely for later use. The nickel-based alloy powder has the following composition by mass percentage: Cr 22.13%, W 14.55%, Mo 2.8%, C 0.12%, Si 0.38%, Mn 0.5%, Fe 1.89%, Co 2.4%, Al 0.43%, Ti 0.08%, Cu 0.47%, La 0.02%, B 0.015%, with the balance being Ni and unavoidable impurities.

[0056] Step 2: Design the component model to be formed in Solidworks software and slice it to obtain multiple slice models. The overhang angle of the unsupported overhang area of ​​the component model is 25°, the thickness of the unsupported overhang area is 1.2mm, and there is no solid area.

[0057] Step 3: Based on multiple slice models, determine the unsupported overhang area of ​​each slice model.

[0058] Step 4: Laser selective melting and forming parameters for the unsupported overhanging area include overhanging laser power, overhanging scanning speed, and overhanging scanning spacing. The overhanging laser power is 120W, the overhanging scanning speed is 1200mm / s, the overhanging scanning spacing is 0.1mm, and the laser scanning strategy for the unsupported overhanging area is 67° overall scanning.

[0059] Step 5: Based on the laser selective melting forming parameters of the unsupported overhanging region, determine the number of laser remelting times for the unsupported overhanging region to be 2.

[0060] Step 6: Clean the surface of the 316L stainless steel substrate; pre-form the dried nickel-based alloy powder into the powder feeding chamber; place the cleaned 316L stainless steel substrate on the lifting platform and close all doors to ensure equipment sealing; introduce 99.99% argon gas into the forming chamber until the oxygen content is below 100ppm; adjust the upper surface of the 316L stainless steel substrate to be flush with the lower surface of the equipment scraper; preheat the 316L stainless steel substrate to 100℃ using resistance heating.

[0061] Step 7: Based on the forming parameters of the unsupported overhanging area, lay nickel-based alloy powder with a thickness of 0.04 mm layer by layer, and use a laser selective melting device to form the unsupported overhanging area of ​​each layer of nickel-based alloy powder and remelt it multiple times, and repeat this process until the laser selective melting device completes the laser melting and forming of all layers of nickel-based alloy powder, thereby obtaining the unsupported nickel-based alloy component.

[0062] Please see also Figure 7 , Figure 8 , Figure 9 and Figure 12 The GH3230 unsupported component prepared in Example 1 has a density of 99.31% and a lower surface roughness Sa=16.37μm. It exhibits no obvious slag, pits, or melt-through areas, and the overall lower surface is relatively uniformly formed. Because the multiple remelting processes during this forming process avoid short-term, repeated heat input to the unsupported overhanging area, overheating, melt-through, and warping deformation in the unsupported overhanging area are avoided.

[0063] Comparative Example 1 This embodiment provides a method for forming the lower surface of components with different angled overhangs in nickel-based superalloys, including the following steps: Step 1: Dry the nickel-based alloy powder with a particle size of 15μm~53μm in a vacuum-protected drying oven and store it safely for later use. The nickel-based alloy powder has the following composition by mass percentage: Cr 22.13%, W 14.55%, Mo 2.8%, C 0.12%, Si 0.38%, Mn 0.5%, Fe 1.89%, Co 2.4%, Al 0.43%, Ti 0.08%, Cu 0.47%, La 0.02%, B 0.015%, with the balance being Ni and unavoidable impurities.

[0064] Step 2: Design the component model to be formed in Solidworks software and slice it. The overhang angle of the unsupported overhang area of ​​the component model is 25°, the thickness of the unsupported overhang area is 1.2mm, and there is no solid area.

[0065] Step 3: Based on multiple slice models, determine the unsupported overhang area of ​​each slice model.

[0066] Step 4: Laser selective melting and forming parameters for the unsupported overhanging area include overhanging laser power, overhanging scanning speed, and overhanging scanning spacing. The overhanging laser power is 210W, the overhanging scanning speed is 900mm / s, the overhanging scanning spacing is 0.09mm, and the laser scanning strategy for the unsupported overhanging area is 67° overall scanning.

[0067] Step 5: Clean the surface of the 316L stainless steel substrate; pre-form the dried nickel-based alloy powder into the powder feeding chamber; place the cleaned 316L stainless steel substrate on the lifting platform and close all doors to ensure equipment sealing; introduce 99.99% argon gas into the forming chamber until the oxygen content is below 100ppm; adjust the upper surface of the 316L stainless steel substrate to be flush with the lower surface of the equipment scraper; preheat the 316L stainless steel substrate to 100℃ using resistance heating.

[0068] Step 6: Based on the forming parameters of the unsupported overhanging area, nickel-based alloy powder with a thickness of 0.04 mm is laid layer by layer, and the unsupported overhanging area of ​​each layer of nickel-based alloy powder is formed and remelted multiple times by a laser selective melting device, and this process is repeated until the laser selective melting device completes the laser melting and forming of all layers of nickel-based alloy powder, thereby obtaining the unsupported nickel-based alloy component.

[0069] Please see also Figure 7 , Figure 8 , Figure 9 and Figure 12 The density of the GH3230 unsupported component prepared in Comparative Example 1 was 99.44%, and the lower surface roughness Sa = 53.44 μm. Obvious protruding areas and a few discrete small protruding areas were observed. It can be assumed that the large protruding areas are due to melt-through, and the small discrete protruding areas are slag-laden areas. The density was not significantly different from that of Example 1, but the lower surface roughness of the unsupported overhanging areas decreased significantly. Because this forming method used conventional laser power, scanning speed, and scanning spacing, heat accumulation was severe, resulting in greater thermal stress and severe warping with a warping height exceeding 300 μm, seriously affecting the dimensional accuracy of the component.

[0070] Comparative Example 2 This embodiment provides a method for forming the lower surface of components with different angled overhangs in nickel-based superalloys, including the following steps: Step 1: Dry the nickel-based alloy powder with a particle size of 15μm~53μm in a vacuum-protected drying oven and store it safely for later use. The nickel-based alloy powder has the following composition by mass percentage: Cr 22.13%, W 14.55%, Mo 2.8%, C 0.12%, Si 0.38%, Mn 0.5%, Fe 1.89%, Co 2.4%, Al 0.43%, Ti 0.08%, Cu 0.47%, La 0.02%, B 0.015%, with the balance being Ni and unavoidable impurities.

[0071] Step 2: Design the component model to be formed in Solidworks software and slice it. The overhang angle of the unsupported overhang area of ​​the component model is 25°, the thickness of the unsupported overhang area is 1.2mm, and there is no solid area.

[0072] Step 3: Based on multiple slice models, determine the unsupported overhang area of ​​each slice model.

[0073] Step 4: Laser selective melting and forming parameters for the unsupported overhanging area include overhanging laser power, overhanging scanning speed, and overhanging scanning spacing. The overhanging laser power is 185W, the overhanging scanning speed is 1100mm / s, the overhanging scanning spacing is 0.1mm, and the laser scanning strategy for the unsupported overhanging area is 67° cross-strip scanning.

[0074] Step 5: Clean the surface of the 316L stainless steel substrate; pre-form the dried nickel-based alloy powder into the powder feeding chamber; place the cleaned 316L stainless steel substrate on the lifting platform and close all doors to ensure equipment sealing; introduce 99.99% argon gas into the forming chamber until the oxygen content is below 100ppm; adjust the upper surface of the 316L stainless steel substrate to be flush with the lower surface of the equipment scraper; preheat the 316L stainless steel substrate to 100℃ using resistance heating.

[0075] Step 6: Based on the forming parameters of the unsupported overhanging area, nickel-based alloy powder with a thickness of 0.04 mm is laid layer by layer, and the unsupported overhanging area of ​​each layer of nickel-based alloy powder is formed and remelted multiple times by a laser selective melting device, and this process is repeated until the laser selective melting device completes the laser melting and forming of all layers of nickel-based alloy powder, thereby obtaining the unsupported nickel-based alloy component.

[0076] Please see also Figure 7 , Figure 8 , Figure 9 and Figure 12The density of the unsupported GH3230 component prepared in Comparative Example 2 was 92.63%, and it contained numerous discontinuous areas. The lower surface roughness Sa = 20.65 μm, with no obvious slag or melt-through areas, but significant discontinuities in the weld lines were present, indicating large pits on the lower surface. Although the lower surface roughness was not significantly different from that of Example 1, and this forming scheme avoided severe warping due to lower heat input and lower strength, the presence of numerous porosities and incomplete fusion defects severely affected the component quality.

[0077] Example 2 This embodiment provides a method for forming the lower surface of components with different angled overhangs in nickel-based superalloys, including the following steps: Step 1: Dry the nickel-based alloy powder with a particle size of 15μm~53μm in a vacuum-protected drying oven and store it safely for later use. The nickel-based alloy powder has the following composition by mass percentage: Cr 22.13%, W 14.55%, Mo 2.8%, C 0.12%, Si 0.38%, Mn 0.5%, Fe 1.89%, Co 2.4%, Al 0.43%, Ti 0.08%, Cu 0.47%, La 0.02%, B 0.015%, with the balance being Ni and unavoidable impurities.

[0078] Step 2: Design the component model to be formed in Solidworks software and slice it to obtain multiple slice models. The overhang angle of the unsupported overhang area of ​​the component model is 25°, the thickness of the unsupported overhang area is 3mm, the width of the solid area is 2.6mm, the width of the unsupported overhang area is 0.5mm, and the overlap area between the two is 0.1mm.

[0079] Step 3: Based on multiple slice models, determine the protrusion length and overhang angle of each slice model relative to the adjacent slice models; based on the protrusion length and overhang angle, divide each slice model into an unsupported overhang area and a solid area.

[0080] Step 4: Laser selective melting and forming parameters for the solid area include solid laser power, solid scanning speed, and solid scanning spacing. The solid laser power is 210W, the solid scanning speed is 900mm / s, and the solid scanning spacing is 0.09mm. The laser scanning strategy for the solid area is a 67° cross-strip scanning. Laser selective melting and forming parameters for the unsupported overhanging area include overhang laser power, overhang scanning speed, and overhang scanning spacing. The overhang laser power is 120W, the overhang scanning speed is 1200mm / s, and the overhang scanning spacing is 0.1mm. The laser scanning strategy for the unsupported overhanging area is a 67° cross-strip scanning.

[0081] Step 5: Based on the laser selective melting forming parameters of the unsupported overhanging region, determine the number of laser remelting times for the unsupported overhanging region to be 2.

[0082] Step 6: Clean the surface of the 316L stainless steel substrate; pre-form the dried nickel-based alloy powder into the powder feeding chamber; place the cleaned 316L stainless steel substrate on the lifting platform and close all doors to ensure equipment sealing; introduce 99.99% argon gas into the forming chamber until the oxygen content is below 100ppm; adjust the upper surface of the 316L stainless steel substrate to be flush with the lower surface of the equipment scraper; preheat the 316L stainless steel substrate to 100℃ using resistance heating.

[0083] Step 7: Based on the forming parameters of the unsupported overhanging region and the solid region, nickel-based alloy powder with a thickness of 0.04 mm is laid layer by layer. The solid region of each layer of nickel-based alloy powder is formed first by a laser selective melting device, and then the unsupported overhanging region is formed and remelted multiple times. This process is repeated until the laser selective melting device completes the laser melting and forming of all layers of nickel-based alloy powder, thereby obtaining a nickel-based alloy unsupported component.

[0084] Please see also Figure 10 , Figure 11 and Figure 12 The density of the GH3230 unsupported component prepared in Example 2 was 99.36%, the surface roughness Sa=17.67μm, and there were no obvious slag, pits or melt-through areas. The overall shape of the lower surface was relatively uniform.

[0085] Comparative Example 3 This embodiment provides a method for forming the lower surface of components with different angled overhangs in nickel-based superalloys, including the following steps: Step 1: Dry the nickel-based alloy powder with a particle size of 15μm~53μm in a vacuum-protected drying oven and store it safely for later use. The nickel-based alloy powder has the following composition by mass percentage: Cr 22.13%, W 14.55%, Mo 2.8%, C 0.12%, Si 0.38%, Mn 0.5%, Fe 1.89%, Co 2.4%, Al 0.43%, Ti 0.08%, Cu 0.47%, La 0.02%, B 0.015%, with the balance being Ni and unavoidable impurities.

[0086] Step 2: Design the component model to be formed in Solidworks software and slice it to obtain multiple slice models. The overhang angle of the unsupported overhang area of ​​the component model is 25°, the thickness of the unsupported overhang area is 3mm, the width of the solid area is 2.6mm, the width of the unsupported overhang area is 0.5mm, and the overlap area between the two is 0.1mm.

[0087] Step 3: Based on multiple slice models, determine the protrusion length and overhang angle of each slice model relative to its adjacent slice models; based on the protrusion length and overhang angle, divide each slice model into an unsupported overhang area and a solid area. The length of the unsupported overhang area in each layer is twice the protrusion length.

[0088] Step 4: Laser selective melting and forming parameters for the solid area include solid laser power, solid scanning speed, and solid scanning spacing. The solid laser power ranges from 210W, the solid scanning speed ranges from 900mm / s, and the solid scanning spacing ranges from 0.09mm. The laser scanning strategy for the solid area is a 67° cross-strip scanning. Laser selective melting and forming parameters for the unsupported overhanging area include overhang laser power, overhang scanning speed, and overhang scanning spacing. The overhang laser power is 170W, the overhang scanning speed is 1100mm / s, and the overhang scanning spacing is 0.1mm. The laser scanning strategy for the unsupported overhanging area is a 67° cross-strip scanning.

[0089] Step 5: Clean the surface of the 316L stainless steel substrate; pre-form the dried nickel-based alloy powder into the powder feeding chamber; place the cleaned 316L stainless steel substrate on the lifting platform and close all doors to ensure equipment sealing; introduce 99.99% argon gas into the forming chamber until the oxygen content is below 100ppm; adjust the upper surface of the 316L stainless steel substrate to be flush with the lower surface of the equipment scraper; preheat the 316L stainless steel substrate to 100℃ using resistance heating.

[0090] Step 6: Based on the forming parameters of the unsupported overhanging region and the solid region, nickel-based alloy powder with a thickness of 0.04 mm is laid layer by layer. The solid region of each layer of nickel-based alloy powder is formed first by a laser selective melting device, and then the unsupported overhanging region is formed and remelted multiple times until the laser selective melting device completes the laser melting and forming of all layers of nickel-based alloy powder, thereby obtaining the unsupported nickel-based alloy component.

[0091] Please see also Figure 10 , Figure 11 and Figure 12 The density of the GH3230 unsupported component prepared in Comparative Example 3 was 92.72%, and the surface roughness Sa=21.42μm. There were no obvious pits or melt-through areas, but there was slight slag adhesion. Because the forming parameters were reduced in the overhanging area, dense forming could not be achieved. In particular, at the junction of the solid area and the overhanging area, there were obvious pores and incomplete fusion, which seriously affected the forming quality of the component.

[0092] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be embraced within this application.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A method for forming the lower surface of components in the overhanging region of nickel-based superalloys at different angles, characterized in that, Includes the following steps: Obtain the component model and slice the component model to obtain multiple slice models; Based on multiple slice models, each slice model is divided into an unsupported overhang region and a solid region, wherein the overhang angle of the unsupported overhang region of the component model is 20° to 45°. The laser selective melting forming parameters for the unsupported overhanging region and the laser selective melting forming parameters for the solid region are set, wherein the heat input of the unsupported overhanging region is lower than the heat input of the solid region; Based on the laser selective melting forming parameters of the unsupported overhanging region, the number of laser remelting times for the unsupported overhanging region is determined. Based on the forming parameters of the unsupported overhanging region and the forming parameters of the solid region, nickel-based alloy powder is laid layer by layer. The solid region of each layer of nickel-based alloy powder is first formed by a laser selective melting device. Then, the unsupported overhanging region is formed and remelted multiple times in sequence. This process is repeated until the laser selective melting device completes the laser melting and forming of all layers of nickel-based alloy powder, thereby obtaining a nickel-based alloy unsupported component.

2. The method for forming the lower surface of components with different angled overhangs in nickel-based superalloys as described in claim 1, characterized in that, The nickel-based alloy powder is composed of the following components by mass percentage: Cr 20%-24%, W 13%-15%, Mo 1%-3%, C 0.05%-0.2%, Si 0.2%-0.5%, Mn 0.2%-1%, Co 2%-4%, La 0.01-0.1%, Fe 1%-3%, Al less than 1%, Ti less than 0.1%, Cu less than 0.5%, B less than 0.01%, with the balance being Ni and unavoidable impurities.

3. The method for forming the lower surface of components with different angled overhangs in nickel-based superalloys as described in claim 1, characterized in that, Before the step of obtaining the component model and slicing the component model, the method further includes: Nickel-based alloy powder with a particle size of 15μm~53μm was dried in a vacuum-protected drying oven and stored safely for later use. Design a component model in 3D software, wherein the overhang angle of the unsupported overhanging area of ​​the component model is 20°. 45°.

4. The method for forming the lower surface of components with different angled overhangs in nickel-based superalloys as described in claim 1, characterized in that, The step of dividing each slice model into an unsupported overhang region and a solid region based on multiple slice models specifically includes: Based on multiple slice models, determine the protrusion length and overhang angle of each slice model relative to the adjacent slice models; Based on the protrusion length and the overhang angle, each slice model is divided into the unsupported overhang area and the solid area.

5. The method for forming the lower surface of components with different angled overhangs in nickel-based superalloys as described in claim 4, characterized in that, The length of the unsupported overhanging area in each layer is twice the protruding length.

6. The method for forming the lower surface of components with different angled overhangs in nickel-based superalloys as described in claim 1, characterized in that, The steps preceding the layer-by-layer laying of nickel-based alloy powder include: The dried nickel-based alloy powder is pre-formed in the powder feeding chamber. After the cleaned substrate is placed on the lifting platform of the forming chamber, all the doors are closed. Argon gas is introduced into the forming chamber until the oxygen content is below 100 ppm, and the substrate is preheated to 90°C to 110°C.

7. The method for forming the lower surface of components with different angled overhangs in nickel-based superalloys as described in claim 1, characterized in that, The laser selective melting forming parameters for the unsupported overhanging area include overhanging laser power, overhanging scanning speed, and overhanging scanning spacing. The overhanging laser power ranges from 100W to 160W, the overhanging scanning speed ranges from 800mm / s to 1500mm / s, and the overhanging scanning spacing ranges from 0.07mm to 0.12mm.

8. The method for forming the lower surface of components with different angled overhangs in nickel-based superalloys as described in claim 1, characterized in that, The laser selective melting forming parameters of the physical region include physical laser power, physical scanning speed, and physical scanning spacing. The physical laser power ranges from 185W to 235W, the physical scanning speed ranges from 600mm / s to 1000mm / s, and the physical scanning spacing ranges from 0.07mm to 0.12mm.

9. The method for forming the lower surface of components with different angled overhangs in nickel-based superalloys as described in claim 1, characterized in that, The laser scanning strategy for the unsupported overhanging area is a whole-area scan, while the laser scanning strategy for the solid area is a 67° cross-strip scan. The thickness of each layer of the nickel-based alloy powder ranges from 0.02 mm to 0.05 mm.

10. The method for forming the lower surface of a nickel-based superalloy component with different angled overhangs as described in claim 1, characterized in that, The steps following the determination of the number of laser remelting cycles for the unsupported overhang region include: The laser selective melting forming parameters of the multiple slice models, the laser selective melting forming parameters of the unsupported overhanging region, the laser selective melting forming parameters of the solid region, and the number of laser remelting times of the unsupported overhanging region are input into the laser selective melting device to obtain a pre-demonstration nickel-based alloy unsupported component model. Based on the fact that the pre-demonstration nickel-based alloy unsupported component model conforms to the standard, it is confirmed that the laser selective melting forming parameters and the slicing model are correct.

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