High-efficiency selective laser melting forming titanium alloy component machining method

Abstract

The invention provides a high-efficiency selective laser melting forming titanium alloy component processing method which comprises the following steps: predicting a product printing process by adopting process simulation, and segmenting a single product digital model into a plurality of product digital model blocks according to predicted residual stress distribution, surface quality requirements or structural fineness; different powder layer thicknesses and energy inputs are given to different blocks; dividing each block by taking the thickness of the powder layer as a spacing to form a two-dimensional contour, and performing forming path planning filling on the two-dimensional contour according to process parameters to form a machining program; according to the machining procedure, large-particle-size TA15 titanium alloy powder is adopted for selective laser melting forming machining. According to the method, the high-efficiency selective laser melting forming efficiency of the titanium alloy part is remarkably improved, the machining cost is reduced, and meanwhile the problems that an existing titanium alloy part is prone to deformation, cracking and the like are solved.

Description

Technical Field

[0001] This invention belongs to the field of laser selective melting forming technology, and particularly relates to a high-efficiency laser selective melting forming method for processing titanium alloy components. Background Technology

[0002] Selective laser melting (SLM) is currently the mainstream metal additive manufacturing process. It employs a process of layer-by-layer metal powder spreading and scanning to melt specific areas of powder point-by-point, line-by-line, and layer-by-layer to achieve the desired shape. The resulting parts have high precision and excellent internal quality, and are widely used in the rapid development of complex components in aerospace, new power systems, and other fields. However, SLM still suffers from low forming efficiency and high processing costs, hindering its further transformation into mass production. The main factor affecting efficiency is the forming machine time, which can easily reach tens of days. The cost is influenced by both the machine time cost and the cost of the metal powder used. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0004] This invention provides a high-efficiency laser selective melting forming method for processing titanium alloy components, which includes:

[0005] Process simulation is used to predict the residual stress distribution, surface quality requirements, or structural fineness during the product printing process. Based on the predicted residual stress distribution, surface quality requirements, or structural fineness, the digital model of a single product is divided into several product digital model blocks.

[0006] Based on the residual stress, surface quality requirements, or structural fineness of different segments, different powder layer thicknesses and energy inputs are assigned to different segments.

[0007] Each segment is divided into two-dimensional contours with the powder layer thickness as the spacing. Then, according to the corresponding process parameters of the energy input, the forming path of the two-dimensional contours is planned and filled to form a processing program.

[0008] According to the processing procedure, large-particle-size TA15 titanium alloy powder is used for laser selective melting and forming.

[0009] Furthermore, when using process simulation for prediction, the layer-by-layer printing deposition process is simulated by activating the mesh layer by layer.

[0010] Furthermore, the powder layer thickness and energy input of segments with residual stress concentration, relatively higher surface quality requirements, or relatively finer structures are less than those of segments without residual stress concentration, relatively lower surface quality requirements, or relatively less finer structures.

[0011] Furthermore, for sections with concentrated residual stress, high surface quality requirements, or fine structures, the powder layer thickness and process parameter ranges are as follows:

[0012] (1) Layer thickness: 40~60μm;

[0013] (2) Main filling process parameters: Laser power: 150~280W; Spot scanning speed: 1200mm / s~1500mm / s; Scanning track spacing: 0.08mm~0.10mm; Scanning strategy: checkerboard scanning;

[0014] (3) Contour process parameters: Laser power: 200W~300W; Spot scanning speed: 500mm / s~1400mm / s.

[0015] Furthermore, for sections with no residual stress concentration, low surface quality requirements, or imprecise structure, the powder layer thickness and process parameter ranges are as follows:

[0016] (1) Layer thickness: 90~130μm;

[0017] (2) Main filling process parameters: Laser power: 320W~420W; Spot scanning speed: 800mm / s~1500mm / s; Scanning track spacing: 0.10mm~0.14mm; Scanning strategy: strip scanning or no-zone scanning;

[0018] (3) Contour process parameters: Laser power: 300W~400W; Spot scanning speed: 600mm / s~1200mm / s.

[0019] Furthermore, the particle size range of the large-particle-size TA15 titanium alloy powder is: D10≤30μm, 40μm≤D50≤60μm, 65μm≤D90≤85μm.

[0020] Furthermore, during the laser selective melting forming process, the oxygen content of the forming equipment is controlled to be 100–300 ppm, and the powder spreading speed is 80–120 mm / s.

[0021] Furthermore, after completing the laser selective melting forming process, the high-efficiency laser selective melting forming titanium alloy component processing method also includes: removing excess powder from the inside and outside of the product, performing stress-relief annealing heat treatment on the product and the substrate; cutting and separating the product from the substrate to complete the component processing and production.

[0022] This invention provides a high-efficiency laser selective melting forming method for titanium alloy components. This method divides a single product digital model into several product digital model blocks, assigns different powder layer thicknesses and process parameters to different blocks, and uses large-particle-size TA15 titanium alloy powder for laser selective melting forming. This invention significantly improves the efficiency of high-efficiency laser selective melting forming of titanium alloy parts, reduces processing costs, and simultaneously improves existing problems such as deformation and cracking that are prone to occur in titanium alloy parts. Attached Figure Description

[0023] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0024] Figure 1 A schematic flowchart of a high-efficiency laser selective melting forming method for titanium alloy components according to a specific embodiment of the present invention is shown.

[0025] Figure 2 A schematic diagram of the product digital model breakdown provided according to a specific embodiment of the present invention is shown;

[0026] Figure 3 A metallographic schematic diagram of the formed product is shown according to a specific embodiment of the present invention. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0030] like Figure 1 As shown, a high-efficiency laser selective melting forming method for processing titanium alloy components is provided according to a specific embodiment of the present invention. The method includes:

[0031] Process simulation is used to predict the residual stress distribution, surface quality requirements, or structural fineness during the product printing process. Based on the predicted residual stress distribution, surface quality requirements, or structural fineness, the digital model of a single product is divided into several product digital model blocks.

[0032] Based on the residual stress, surface quality requirements, or structural fineness of different segments, different powder layer thicknesses and energy inputs are assigned to different segments.

[0033] Each segment is divided into two-dimensional contours with the powder layer thickness as the spacing. Then, according to the corresponding process parameters of the energy input, the forming path of the two-dimensional contours is planned and filled to form a processing program.

[0034] According to the processing procedure, large-particle-size TA15 titanium alloy powder is used for laser selective melting and forming.

[0035] This configuration provides a high-efficiency laser selective melting forming method for titanium alloy components. The method divides a single product digital model into several product digital model blocks, assigns different powder layer thicknesses and energy inputs to different blocks, and uses large-particle-size TA15 titanium alloy powder for laser selective melting forming. The technical solution of this invention significantly improves the efficiency of high-efficiency laser selective melting forming of titanium alloy parts, reduces processing costs, and simultaneously improves existing problems such as deformation and cracking that are prone to occur in titanium alloy parts.

[0036] Since selective laser melting (SLM) processes powder layer by layer, the thickness of the powder layer directly affects the overall processing efficiency and quality. To ensure stable and reliable product quality while improving processing efficiency, this invention implements zoned settings for powder layer thickness and energy input in the SLM method.

[0037] First, in this invention, process simulation is used to predict the residual stress distribution, surface quality requirements, or structural fineness of the product printing process; based on the predicted residual stress distribution, surface quality requirements, or structural fineness, a single product digital model is divided into several product digital model blocks.

[0038] The process of layer-by-layer printing deposition can be simulated by activating the mesh layer by layer. After all meshes are activated, the residual stress distribution of the entire product's digital model is mapped.

[0039] Furthermore, based on the residual stress, surface quality requirements, or structural fineness corresponding to different segments, different powder layer thicknesses and energy inputs are assigned to different segments.

[0040] As a specific embodiment of the present invention, a single product digital model can be divided into two product digital model blocks according to the predicted residual stress distribution, surface quality requirements, or structural fineness.

[0041] For sections with residual stress concentration, higher surface quality requirements, or more refined structures, a smaller powder layer thickness (denoted as S) and a smaller energy input are used; for sections without residual stress concentration, lower surface quality requirements, or less refined structures, a larger powder layer thickness (denoted as L) and a larger energy input are used.

[0042] For example, small-area concentrated stress zones with residual stress ≥ 900 MPa pose a risk of plastic deformation, and further, small-area concentrated stress zones with residual stress ≥ 950 MPa pose a risk of cracking. Therefore, for residual stress concentrated zones with residual stress ≥ 900 MPa, a smaller powder layer thickness and a smaller energy input are used; while for non-stress concentrated zones with residual stress < 900 MPa, a larger powder layer thickness and a larger energy input are used.

[0043] For sections with relatively higher surface quality requirements or more refined structures, such as sections requiring a surface roughness Ra ≤ 10 μm or sections with a feature size ≤ 1 mm, a smaller powder layer thickness and a smaller energy input are used. Conversely, for sections with relatively lower surface quality requirements or less refined structures, such as sections requiring a surface roughness Ra ≤ 20 μm or sections with a feature size ≥ 3 mm, a larger powder layer thickness and a larger energy input are used.

[0044] Specifically, the powder layer thickness L is greater than the powder layer thickness S, and the powder layer thickness L should be an integer multiple of the powder layer thickness S.

[0045] As a specific embodiment of the present invention, for sections with concentrated residual stress, relatively higher surface quality requirements, or relatively finer structures, the process parameter ranges corresponding to powder layer thickness and energy input are as follows:

[0046] (1) Layer thickness: 40~60μm;

[0047] (2) Main filling process parameters: Laser power: 150~280W; Spot scanning speed: 1200mm / s~1500mm / s; Scanning track spacing: 0.08mm~0.10mm; Scanning strategy: checkerboard scanning;

[0048] (3) Contour process parameters: Laser power: 200W~300W; Spot scanning speed: 500mm / s~1400mm / s.

[0049] For non-residual stress concentration sections, sections with relatively lower surface quality requirements, or sections with relatively less refined structures, the corresponding process parameter ranges for powder layer thickness and energy input are as follows:

[0050] (1) Layer thickness: 90~130μm;

[0051] (2) Main filling process parameters: Laser power: 320W~420W; Spot scanning speed: 800mm / s~1500mm / s; Scanning track spacing: 0.10mm~0.14mm; Scanning strategy: strip scanning or no-zone scanning;

[0052] (3) Contour process parameters: Laser power: 300W~400W; Spot scanning speed: 600mm / s~1200mm / s.

[0053] Furthermore, each segment is divided into two-dimensional contours with the powder layer thickness as the spacing. Then, according to the corresponding process parameters of the energy input, the two-dimensional contours are filled with forming paths to form a processing program. According to the processing program, large-particle-size TA15 titanium alloy powder is used for laser selective melting forming processing.

[0054] The particle size range of the large-particle-size TA15 titanium alloy powder is: D10≤30μm, 40μm≤D50≤60μm, 65μm≤D90≤85μm.

[0055] During the processing, the oxygen content of the forming equipment can be controlled at 100-300 ppm, the powder spreading speed at 80-120 mm / s, and the spreading of large-particle-size TA15 titanium alloy powder can be monitored.

[0056] Furthermore, after processing, excess powder is removed from both the inside and outside of the product, and the product and substrate undergo stress-relief annealing heat treatment together. Wire EDM is then used to separate the product from the substrate, completing the component manufacturing process.

[0057] The high-efficiency laser selective melting forming method for titanium alloy components of this invention divides a single product digital model into several product digital model blocks. Based on the residual stress, surface quality requirements, or structural fineness of each block, the powder layer thickness and energy input are adjusted. This processing method significantly improves the processing efficiency of complex components, especially complex TA15 titanium alloy components, through laser selective melting forming, thereby reducing processing costs.

[0058] To gain a further understanding of the present invention, the high-efficiency laser selective melting forming method for titanium alloy components of the present invention will be described in detail below with reference to specific embodiments.

[0059] For a part to be formed (height 220mm, diameter 300mm), process simulation is used to simulate the product. The digital model of the part is split into two parts, such as... Figure 2 As shown, part A is the stress concentration region, and part B is the non-stress concentration region.

[0060] The process parameters used in Part A are as follows:

[0061] (1) Layer thickness: 50μm;

[0062] (2) Main filling process parameters: Laser power: 210W; Spot scanning speed: 1300mm / s; Scanning track spacing: 0.09mm; Scanning strategy: checkerboard scanning;

[0063] (3) Contour process parameters: Laser power: 210W; Spot scanning speed: 800mm / s;

[0064] The process parameters used in Part B are as follows:

[0065] (1) Layer thickness: 100μm;

[0066] (2) Main filling process parameters: Laser power: 330W; Spot scanning speed: 1200mm / s; Scanning track spacing: 0.1mm; Scanning strategy: strip scanning;

[0067] (3) Contour process parameters: Laser power: 360W; Spot scanning speed: 800mm / s;

[0068] The product was formed using TA15 powder with particle sizes of D10 = 22.9 μm, D50 = 44.2 μm, and D90 = 73.1 μm; the oxygen content was controlled at 100 ppm, and the powder spreading speed was 100 mm / s.

[0069] The product has a molding time of 68 hours and good internal quality. Its mechanical properties reach the level of 1054 MPa tensile strength at room temperature, 14% elongation after fracture at room temperature, and 742 MPa tensile strength at 500℃.

[0070] In contrast, conventional component processing methods without segmentation use a powder layer thickness of 60 μm, have a forming time of 126 hours, and are prone to stress concentration and cracking in some areas. However, the method of this invention reduces the forming time by 46%, eliminates the risk of cracking, significantly improves production efficiency, and reduces production costs.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of processing a titanium alloy component formed by high efficiency laser selective melting, characterized in that, The high-efficiency laser selective melting forming titanium alloy component processing method comprises the following steps: The residual stress distribution, surface quality requirement or structural fineness in the product printing process is predicted by process simulation, and the single product digital model is divided into several product digital model blocks according to the predicted residual stress distribution, surface quality requirement or structural fineness; Different powder layer thicknesses and energy inputs are given to different blocks according to the residual stress, surface quality requirement or structural fineness corresponding to different blocks; Each block is divided into a two-dimensional contour at the interval of the powder layer thickness, and the two-dimensional contour is filled according to the process parameters corresponding to the energy input to form a machining program; The laser selective melting forming processing is performed on the TA15 titanium alloy powder with large particle size according to the machining program.

2. The high-efficiency laser selective melting forming method for titanium alloy components according to claim 1, characterized in that, When the process simulation is used for prediction, the grid is activated layer by layer to simulate the layer-by-layer printing deposition process.

3. The high-efficiency laser selective melting forming method for titanium alloy components according to claim 1, characterized in that, The powder layer thickness and energy input of the block with high residual stress concentration, high surface quality requirement or fine structure are smaller than those of the block without residual stress concentration, low surface quality requirement or non-fine structure.

4. The high-efficiency laser selective melting forming method for titanium alloy components according to claim 3, characterized in that, For the block with high residual stress concentration, high surface quality requirement or fine structure, the powder layer thickness and process parameter range are as follows: (1) Layer thickness: 40-60 μm; (2) Main filling process parameters: laser power: 150-280 W; spot scanning speed: 1200 mm / s-1500 mm / s; scanning path spacing: 0.08 mm-0.10 mm; scanning strategy: chessboard scanning; (3) Contour process parameters: laser power: 200-300 W; spot scanning speed: 500 mm / s-1400 mm / s.

5. The high-efficiency laser selective melting forming method for titanium alloy components according to claim 4, characterized in that, For the block without residual stress concentration, low surface quality requirement or non-fine structure, the powder layer thickness and process parameter range are as follows: (1) Layer thickness: 90-130 μm; (2) Main filling process parameters: laser power: 320-420 W; spot scanning speed: 800 mm / s-1500 mm / s; scanning path spacing: 0.10 mm-0.14 mm; scanning strategy: strip scanning or non-partition scanning; (3) Contour process parameters: laser power: 300-400 W; spot scanning speed: 600 mm / s-1200 mm / s. The particle size range of the TA15 titanium alloy powder with large particle size is D10≤30 μm, 40 μm≤D50≤60 μm and 65 μm≤D90≤85 μm. During the laser selective melting forming processing, the oxygen content of the forming equipment is controlled to be 100-300 ppm, and the powder spreading speed is 80-120 mm / s.

6. The high-efficiency laser selective melting forming method for titanium alloy components according to claim 1, characterized in that, After the laser selective melting forming processing is completed, the high-efficiency laser selective melting forming titanium alloy component processing method further comprises the following steps: removing the excess powder inside and outside the product, performing stress relief annealing heat treatment on the product and the substrate, cutting and separating the product from the substrate, and completing the component processing production.

7. The high-efficiency laser selective melting forming method for titanium alloy components according to claim 1, characterized in that, ​ 8. The method of claim 1 to 7, wherein, ​

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