Additive manufacturing method based on molten pool regulation and control

Abstract

The invention relates to the technical field of additive manufacturing, in particular to an additive manufacturing method based on molten pool regulation and control, which comprises the following steps: S1, determining a critical scanning interval hmin meeting the requirement of no internal crack defect under the conditions of specific laser power, scanning speed and scanning layer thickness; and S2, the value range of the scanning interval h of additive manufacturing is determined based on the critical scanning interval hmin. According to the method, the mode that the laser power, the scanning speed and the scanning layer thickness are preferentially determined, and the scanning interval h is further determined on the basis of the geometrical characteristics (depth and width) of the molten pool is adopted, variables of single-time processing are reduced, the additive manufacturing parameter obtaining process is simplified, rapid determination of additive manufacturing process parameters is achieved, and the production efficiency is improved. The problems that in additive manufacturing in the prior art, technological parameters are difficult to determine, multiple defects such as cracks and pores exist, and the yield is low are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to an additive manufacturing method based on molten pool regulation. Background Art

[0002] Additive manufacturing technology is a manufacturing method that accumulates materials to form a solid structure based on 3D model data, among which laser additive manufacturing is widely used. However, due to the characteristics of the metal laser additive manufacturing forming process of layer-by-layer accumulation and rapid cooling, in the metal laser additive manufacturing process, the process parameters such as laser power, scanning speed, scanning spacing, etc. used will affect the geometry and cooling rate of the molten pool, thereby affecting the microstructure characteristics such as the grain structure of the component, and causing internal defects such as cracks and pores.

[0003] At present, the trial-and-error method for optimizing laser additive manufacturing process parameters is time-consuming and economically expensive, and is not conducive to finding suitable laser additive manufacturing process parameters. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide an additive manufacturing method based on melt pool control, so as to solve at least one of the problems existing in the prior art of additive manufacturing, such as difficulty in determining process parameters, many crack and porosity defects, and low yield rate.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] An additive manufacturing method based on molten pool regulation, the additive manufacturing method based on molten pool regulation comprising:

[0007] S1: Determine the critical scanning distance h that satisfies the requirement of no internal crack defects under specific laser power, scanning speed, and scanning layer thickness. min ;

[0008] S2: Based on the critical scanning spacing h min Determine the value range of the scanning spacing h for additive manufacturing.

[0009] Preferably, the value range of the scanning spacing h for additive manufacturing determined in step S2 satisfies: h ≥ h min .

[0010] Preferably, step S1 comprises:

[0011] S101: Obtaining value ranges of process parameters laser power P, scanning speed v, and scanning layer thickness t based on statistical analysis;

[0012] S102: Set the scanning interval h to a value h 1 、h 2 ,…,h i, the corresponding samples are obtained by additive manufacturing under the same conditions within the process parameter value range obtained in S101, where i is the sequence number and h is the i is the scanning spacing of the ith sequence number, h 1 ~h i Increase successively;

[0013] S103: Perform metallographic analysis on the sample, and select the minimum value of the scanning spacing h among the samples that meet the requirement of no internal crack defect as the critical scanning spacing h min .

[0014] Preferably, the additive manufacturing method based on melt pool regulation further comprises: optimizing process parameters based on the matching relationship between the morphology of the melt pool and the additive manufacturing parameters.

[0015] Preferably, the morphological parameters of the molten pool include: molten pool depth D and molten pool width W.

[0016] Preferably, the additive manufacturing method based on molten pool regulation further comprises:

[0017] S3: Optimize the scanning spacing h based on the molten pool width W and the molten pool depth D.

[0018] Preferably, step S3 comprises:

[0019] S301: Obtaining a first upper limit value h of the scanning spacing h based on the molten pool depth D 1 ;

[0020] S302: Obtaining a second upper limit value h of the scanning spacing h based on the molten pool width W 3 ;

[0021] S303: Compare h 1 、h 3 The smaller one is taken as the maximum value of the scanning spacing h max ;

[0022] S304: Scanning interval h satisfies: h min ≤h≤h max .

[0023] Preferably, in S301, a first upper limit value h of the scanning spacing h is obtained based on the molten pool depth D. 1 satisfy:

[0024] When the molten pool depth D = scanning layer thickness t, the corresponding scanning spacing h value is h 1 .

[0025] Preferably, in S302, a second upper limit value h of the scanning spacing h is obtained based on the molten pool width W. 3 satisfy:

[0026] When the molten pool width W = scanning spacing h, the corresponding scanning spacing h value is h 3 .

[0027] A high-temperature nickel-based alloy additively manufactured product is prepared by the additive manufacturing method described above.

[0028] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0029] (1) The present invention adopts a method of preferentially determining the laser power, scanning speed, and scanning layer thickness, and then further determining the scanning spacing h based on the geometric characteristics (depth and width) of the molten pool, thereby reducing the variables of a single processing, simplifying the process of obtaining additive manufacturing parameters, and realizing the rapid determination of additive manufacturing process parameters.

[0030] (2) The present invention determines the critical scanning distance h that satisfies no internal crack defects under specific process conditions. min , and further through h min The scanning interval h is determined, which simplifies the process of obtaining additive manufacturing parameters, realizes the rapid determination of additive manufacturing process parameters, and reduces internal crack defects.

[0031] (3) The present invention optimizes the scanning spacing h based on the molten pool width W and the molten pool depth D. Setting an upper limit for the scanning spacing h can avoid the formation of voids due to unfused powder between the molten pools.

[0032] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0034] Figure 1a This is the relationship between scanning spacing and molten pool depth;

[0035] Figure 1b is the relationship diagram between scanning spacing and molten pool width;

[0036] Figure 2a It is the metallographic diagram of Example 1;

[0037] Figure 2b It is the metallographic diagram of Example 2;

[0038] Figure 2c It is the metallographic diagram of Example 3;

[0039] Figure 2d It is the metallographic diagram of comparative example 1;

[0040] Figure 2e This is the metallographic diagram of Comparative Example 2. DETAILED DESCRIPTION

[0041] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0042] About technical terms

[0043] Molten pool: The molten area of ​​liquid metal that forms the weld during welding is called the molten pool;

[0044] The main dimensions of the molten pool are: penetration, i.e., the depth of the molten pool, and width, i.e., the width of the molten pool. In welding or metal additive manufacturing, the process needs to be adjusted so that the molten pool depth and width meet the product processing requirements and there are no defects such as internal cracks in the molten zone.

[0045] The technical terms of additive manufacturing involved in this invention are:

[0046] Additive manufacturing uses laser to melt raw material powder, and the laser scans the raw material powder layer along a specific trajectory; the thickness of the raw material powder layer is the scanning layer thickness t; the distance between the centers of adjacent laser scanning trajectories is the scanning spacing h, and the moving speed of the laser light source is the scanning speed v.

[0047] In one aspect, the present invention discloses an additive manufacturing method based on molten pool regulation, comprising:

[0048] S1: Determine the critical scanning distance h that satisfies the requirement of no internal crack defects under specific laser power, scanning speed, and scanning layer thickness. min ;

[0049] S2: Based on the critical scanning spacing h min Determine the value range of the scanning spacing h for additive manufacturing.

[0050] During implementation, the high-temperature nickel-based alloy additive manufacturing process parameters, laser power P, scanning speed v, and scanning layer thickness t, are determined; under the above process parameters, the scanning spacing h is set to different gradients of numerical additive manufacturing to obtain samples, and the samples are subjected to metallographic analysis to obtain the minimum value of the scanning spacing h as the critical scanning spacing h min .

[0051] It should be noted that the process parameters for determining the additive manufacturing process parameters of high-temperature nickel-based alloys, such as laser power P, scanning speed v, scanning layer thickness t, and scanning spacing h, will affect the geometry and cooling rate of the molten pool, thereby affecting the microstructural characteristics such as the grain structure of the component, and causing internal defects such as cracks and pores; the existing technology determines the above process parameters at the same time, and it is extremely difficult to determine the appropriate parameters during the additive manufacturing process, especially during the forming of high-temperature nickel-based alloys, to obtain products without internal crack defects.

[0052] Through orthogonal analysis, the applicant found that the correlation between the process parameters of high-temperature nickel-based alloy additive manufacturing, laser power P, scanning speed v, and scanning layer thickness t is much greater than the correlation between the three and the scanning spacing h; compared with the prior art, the present invention adopts a method of preferentially determining the laser power, scanning speed, and scanning layer thickness, and then further determining the scanning spacing h based on the geometric characteristics (depth, width) of the molten pool, which reduces the variables of a single processing, simplifies the process of obtaining additive manufacturing parameters, and realizes the rapid determination of additive manufacturing process parameters.

[0053] Furthermore, the applicant has found that a too small scanning spacing h results in excessive heat concentration in the molten pool during additive manufacturing, which leads to stress concentration during the subsequent cooling process and easily generates defects such as internal cracks. The scanning spacing h has a critical value - critical scanning spacing h min , when h≥h min , which can avoid defects such as internal cracks.

[0054] Compared with the prior art, the present invention determines the critical scanning distance h that satisfies the requirement of no internal crack defects under specific process conditions. min , and further through h min The scanning interval h is determined, which simplifies the process of obtaining additive manufacturing parameters, realizes the rapid determination of additive manufacturing process parameters, and reduces internal crack defects.

[0055] Specifically, step S1 includes:

[0056] S101: Obtaining value ranges of process parameters laser power P, scanning speed v, and scanning layer thickness t based on statistical analysis;

[0057] S102: The scanning interval h is set to h 1 、h 2 ,…,h i , the corresponding samples are obtained by additive manufacturing under the same conditions within the process parameter value range obtained in S101, where i is the sequence number and h is the i is the scanning spacing of the ith sequence number, h 1 ~h i Increase sequentially, and the difference between adjacent values ​​shall not exceed 0.005mm;

[0058] S103: Perform metallographic analysis on the sample, and select the minimum value of the scanning spacing h among the samples that meet the requirement of no internal crack defect as the critical scanning spacing h min .

[0059] Specifically, the process parameters obtained based on statistical analysis in step S101 may be obtained by using a method in the prior art:

[0060] Based on metallographic or scanning electron microscope morphology observations of the samples and repeated experiments, the corresponding relationships between various process parameters and defects were exhaustively enumerated, and the process parameters of laser power P, scanning speed v, and scanning layer thickness t corresponding to the samples with excellent mechanical properties were screened out. The variation range of the process parameters of all samples with excellent mechanical properties was used as the value range of laser power P, scanning speed v, and scanning layer thickness t.

[0061] Specifically, the laser scanning power is 150W to 300W, and can be 150W, 180W, 200W, 230W, 250W, 280W or 300W.

[0062] It should be noted that if the laser power is too small and the energy input is insufficient, the material may not be completely melted, resulting in unfused defects. If the laser power is too large, the material absorbs too much energy, which may cause excessive thermal stress and cracks.

[0063] Specifically, the scanning speed is 600m / s to 2400m / s, which can be 600m / s, 650m / s, 700m / s, 760m / s, 780m / s, 800m / s, 840m / s, 900m / s, 960m / s, 700m / s, 800m / s, 900m / s, 1000m / s, 1060m / s, 1100m / s, 1200m / s, 1320m / s, 1480m / s, 1520m / s, 1600m / s, 1730m / s, 1800m / s, 1860m / s, 1900m / s, 2060m / s, 2200m / s, 2300m / s, 2360m / s or 2400m / s.

[0064] It should be noted that if the scanning speed is too slow, the material will be heated for a long time, resulting in coarse grains and affecting the mechanical properties. If the scanning speed is too fast, the material will be heated for a short time and the powder may be completely melted.

[0065] Specifically, the scanning layer thickness is 0.04 mm to 0.07 mm, and can be 0.04 mm, 0.042 mm, 0.045 mm, 0.05 mm, 0.051 mm, 0.054 mm, 0.058 mm, 0.06 mm, 0.064 mm, 0.068 mm or 0.07 mm.

[0066] It should be noted that if the layer thickness is too small, energy concentration will occur, resulting in deformation. If the layer thickness is too large, uneven powder melting may occur, resulting in unfused defects.

[0067] Furthermore, the present invention decomposes the additive manufacturing forming process into the basic unit of additive manufacturing - the accumulation of the molten pool, and optimizes the process parameters based on the matching relationship between the morphology of the molten pool and the additive manufacturing parameters.

[0068] The applicant found that the molten pool depth D is inversely correlated with the scanning spacing h, satisfying: D∝h -1 , that is, the scanning interval increases and the molten pool depth decreases; in actual processing, the molten pool depth should not be too small, and the molten pool depth should be greater than the scanning layer thickness t, that is, D ≥ t;

[0069] When D = t, h = h 1 , h obtains the first upper limit value, so h should satisfy: h≤h 1 (like Figure 1a shown).

[0070] The applicant also found that the molten pool width W is inversely correlated with the scanning spacing h, satisfying: W∝h -1 , that is, the scanning interval increases and the molten pool width becomes smaller; in actual processing, the molten pool width should not be too small, and the molten pool width should be greater than the scanning interval h, that is, W ≥ h;

[0071] When W=h, h=h 3 , h obtains the second upper limit value, so h should satisfy: h≤h 3 (like Figure 1b shown).

[0072] Specifically, the additive manufacturing method based on molten pool regulation also includes:

[0073] S3: Optimize the scanning spacing h based on the molten pool width W and the molten pool depth D.

[0074] Specifically, step S3 includes:

[0075] S301: Obtaining a first upper limit value h of the scanning spacing h based on the molten pool depth D 1 ;

[0076] S302: Obtaining a second upper limit value h of the scanning spacing h based on the molten pool width W 3 ;

[0077] S303: Compare h 1 、h 3 The smaller one is taken as the maximum value of the scanning spacing h max ;

[0078] S304: Scanning interval h satisfies: h min ≤h≤h max.

[0079] Specifically, the additive manufacturing method based on molten pool regulation also includes:

[0080] S4: Additive manufacturing based on the set laser power P, scanning speed v, scanning layer thickness t, and scanning spacing h.

[0081] Compared with the prior art, the present invention optimizes the scanning spacing h based on the molten pool width W and the molten pool depth D. Setting the upper limit of the scanning spacing h can avoid the formation of voids due to unfused powder between the molten pools.

[0082] Preferably, when a rectangular block having a length×width×height of (10-30) mm×(10-30) mm×(10-30) mm is prepared using high-temperature nickel-based alloy powder, h satisfies: 0.09 mm≤h≤0.13 mm.

[0083] On the other hand, the present invention also discloses a high-temperature nickel-based alloy additively manufactured product, which is prepared by the above-mentioned additive manufacturing method.

[0084] In order to further illustrate the present invention, the following examples and comparative examples are provided:

[0085] Example 1

[0086] This embodiment discloses an additive manufacturing method based on molten pool control, using high-temperature nickel-based alloy 4099 powder, comprising:

[0087] S1. Determine the critical scanning distance h that satisfies the requirement of no internal crack defects under specific laser power, scanning speed and scanning layer thickness. min ;

[0088] S101: Obtaining value ranges of process parameters laser power P, scanning speed v, and scanning layer thickness t based on statistical analysis;

[0089] Based on the metallographic or scanning electron microscope morphology observation of the sample, repeated tests were conducted to exhaustively list the corresponding relationships between various process parameters and defects, and the laser power P, scanning speed v, and scanning layer thickness t process parameters corresponding to the samples with excellent mechanical properties were screened out. The variation range of the process parameters of all samples with excellent mechanical properties was used as the value range of laser power P, scanning speed v, and scanning layer thickness t.

[0090] The laser additive manufacturing process parameters randomly selected from the range of values ​​of laser power P, scanning speed v, and scanning layer thickness t determined in step S101 are: laser scanning power 300 W, scanning speed 1000 m / s, layer thickness 0.06 mm;

[0091] S102: Set the scanning interval h to a value h 1 、h 2 ,…,h i, the corresponding samples are obtained by additive manufacturing under the same conditions within the process parameter value range obtained in S101, where h 1 ~h i Increase successively, the difference between adjacent values ​​= 0.005mm;

[0092] S103: Perform metallographic analysis on the sample, and select the minimum value of the scanning spacing h among the samples that meet the requirement of no internal crack defect as the critical scanning spacing h min =0.09mm.

[0093] S2, based on critical scanning spacing h min Determine the value range of the scanning spacing h for additive manufacturing.

[0094] S3. Optimize the scanning spacing h based on the molten pool width W and the molten pool depth D.

[0095] S301: Obtaining a first upper limit value h of the scanning spacing h based on the molten pool depth D 1 =0.13mm;

[0096] S302: Obtaining a second upper limit value h of the scanning spacing h based on the molten pool width W 3 =0.14mm;

[0097] S303: Compare h 1 、h 3 The smaller one is taken as the maximum value of the scanning spacing h max .

[0098] S304: Scanning interval h satisfies: h min ≤h≤h max , the scanning interval h is 0.1mm.

[0099] S4. Based on the set laser power P, scanning speed v, scanning layer thickness t, and scanning spacing h, a high-temperature nickel-based alloy sample is obtained by additive manufacturing. The printed sample size information is a rectangular block with a length × width × height of 12 mm × 12 mm × 16 mm, including:

[0100] S401: placing the raw materials used for laser additive manufacturing into a vacuum drying box for drying, using a special screening device to screen the dried powder, and adding the screened powder into the printing device;

[0101] S402: Install the processed substrate in the forming cylinder, level the substrate after installation, and wipe the printing surface of the substrate again with cotton-free paper and alcohol after leveling;

[0102] S403: Detect argon pressure, detect compressed air pressure, the testing equipment should operate normally, the testing equipment should be qualified and within the inspection period, turn on the substrate heating plate, and set the preheating temperature to 150°C;

[0103] S404: Start printing. After the printing is completed, the test block is cooled to below 100°C and then taken out and cut from the substrate. Metallographic specimens are made from the three groups of test blocks. Figure 2a As shown, there are no defects such as holes and cracks in the metallographic internal structure.

[0104] Example 2

[0105] This embodiment discloses an additive manufacturing method based on molten pool control, using high-temperature nickel-based alloy 4099 powder, comprising:

[0106] S1. Determine the critical scanning distance h that satisfies the requirement of no internal crack defects under specific laser power, scanning speed and scanning layer thickness. min ;

[0107] S101: Obtaining value ranges of process parameters laser power P, scanning speed v, and scanning layer thickness t based on statistical analysis;

[0108] Based on the metallographic or scanning electron microscope morphology observation of the sample, repeated tests were conducted to exhaustively list the corresponding relationships between various process parameters and defects, and the laser power P, scanning speed v, and scanning layer thickness t process parameters corresponding to the samples with excellent mechanical properties were screened out. The variation range of the process parameters of all samples with excellent mechanical properties was used as the value range of laser power P, scanning speed v, and scanning layer thickness t.

[0109] The process parameters for laser additive manufacturing randomly selected from the range of values ​​of laser power P, scanning speed v, and scanning layer thickness t determined in step S101 are: the process parameters for laser additive manufacturing are: laser scanning power 280 W, scanning speed 1500 m / s, layer thickness 0.06 mm;

[0110] S102: Set the scanning interval h to a value h 1 、h 2 ,…,h i , the corresponding samples are obtained by additive manufacturing under the same conditions within the process parameter value range obtained in S101, where h 1 ~h i Increase successively, the difference between adjacent values ​​= 0.0045mm;

[0111] S103: Perform metallographic analysis on the sample, and select the minimum value of the scanning spacing h among the samples that meet the requirement of no internal crack defect as the critical scanning spacing h min =0.092mm.

[0112] S2, based on critical scanning spacing h min Determine the value range of the scanning spacing h for additive manufacturing.

[0113] S3. Optimize the scanning spacing h based on the molten pool width W and the molten pool depth D.

[0114] S301: Obtaining a first upper limit value h of the scanning spacing h based on the molten pool depth D 1 =0.15mm;

[0115] S302: Obtaining a second upper limit value h of the scanning spacing h based on the molten pool width W 3 =0.13mm;

[0116] S303: Compare h 1 、h 3 The smaller one is taken as the maximum value of the scanning spacing h max .

[0117] S304: Scanning interval h satisfies: h min ≤h≤h max , the scanning spacing h is 0.11mm.

[0118] S4. Based on the set laser power P, scanning speed v, scanning layer thickness t, and scanning spacing h, a high-temperature nickel-based alloy sample is obtained by additive manufacturing. The printed sample size information is a rectangular block with a length × width × height of 24 mm × 28 mm × 21 mm, including:

[0119] S401: placing the raw materials used for laser additive manufacturing into a vacuum drying box for drying, using a special screening device to screen the dried powder, and adding the screened powder into the printing device;

[0120] S402: Install the processed substrate in the forming cylinder, level the substrate after installation, and wipe the printing surface of the substrate again with cotton-free paper and alcohol after leveling;

[0121] S403: Detect argon pressure, detect compressed air pressure, the testing equipment should operate normally, the testing equipment should be qualified and within the inspection period, turn on the substrate heating plate, and set the preheating temperature to 150°C;

[0122] S404: Start printing. After the printing is completed, the test block is cooled to below 100°C and then taken out and cut from the substrate. Metallographic specimens are made from the three groups of test blocks. Figure 2b As shown, there are no defects such as holes and cracks in the metallographic internal structure.

[0123] Example 3

[0124] This embodiment discloses an additive manufacturing method based on molten pool control, using high-temperature nickel-based alloy 4099 powder, comprising:

[0125] S1. Determine the critical scanning distance h that satisfies the requirement of no internal crack defects under specific laser power, scanning speed and scanning layer thickness.min ;

[0126] S101: Based on statistical analysis, the value ranges of the process parameters laser power P, scanning speed v, and scanning layer thickness t are obtained; the process parameters used in laser additive manufacturing are: laser scanning power 250W, scanning speed 1800m / s, and layer thickness 0.04mm;

[0127] S102: The scanning interval h is set to h 1 、h 2 ,…,h i , the corresponding samples are obtained by additive manufacturing under the same conditions within the process parameter value range obtained in S101, where h 1 ~h i Increase successively, the difference between adjacent values ​​= 0.004mm;

[0128] S103: Perform metallographic analysis on the sample, and select the minimum value of the scanning spacing h among the samples that meet the requirement of no internal crack defect as the critical scanning spacing h min =0.095mm.

[0129] S2, based on critical scanning spacing h min Determine the value range of the scanning spacing h for additive manufacturing.

[0130] S3. Optimize the scanning spacing h based on the molten pool width W and the molten pool depth D.

[0131] S301: Obtaining a first upper limit value h of the scanning spacing h based on the molten pool depth D 1 =0.16mm;

[0132] S302: Obtaining a second upper limit value h of the scanning spacing h based on the molten pool width W 3 =0.13mm;

[0133] S303: Compare h 1 、h 3 The smaller one is taken as the maximum value of the scanning spacing h max .

[0134] S304: Scanning interval h satisfies: h min ≤h≤h max , the scanning spacing h is 0.12mm.

[0135] S4. Based on the set laser power P, scanning speed v, scanning layer thickness t, and scanning spacing h, a high-temperature nickel-based alloy sample is obtained by additive manufacturing. The printed sample size information is a rectangular block with a length × width × height of 25 mm × 34 mm × 18 mm, including:

[0136] S401: placing the raw materials used for laser additive manufacturing into a vacuum drying box for drying, using a special screening device to screen the dried powder, and adding the screened powder into the printing device;

[0137] S402: Install the processed substrate in the forming cylinder, level the substrate after installation, and wipe the printing surface of the substrate again with cotton-free paper and alcohol after leveling;

[0138] S403: Detect argon pressure, detect compressed air pressure, the testing equipment should operate normally, the testing equipment should be qualified and within the inspection period, turn on the substrate heating plate, and set the preheating temperature to 150°C;

[0139] S404: Start printing. After the printing is completed, the test block is cooled to below 100°C and then taken out and cut from the substrate. Metallographic specimens are made from the three groups of test blocks. Figure 2c As shown, there are no defects such as holes and cracks in the metallographic internal structure.

[0140] Comparative Example 1

[0141] This comparative example discloses an additive manufacturing method based on molten pool regulation, which is different from Example 1 in that the scanning interval h is 0.14 mm, and the rest is the same as Example 1. The metallographic analysis results are as follows: Figure 2d As shown, there is unmelted powder between the molten pools, and the unmelted powder forms voids.

[0142] Comparative Example 2

[0143] This comparative example discloses an additive manufacturing method based on molten pool regulation, which is different from Example 1 in that the scanning interval h is 0.08 mm, and the rest is the same as Example 1. The metallographic analysis results are as follows: Figure 2e As shown, the energy density between the molten pools is high, forming cracks.

[0144] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An additive manufacturing method based on molten pool control, characterized in that: The additive manufacturing method based on molten pool regulation includes: S1: Determine the critical scanning distance h that satisfies the requirement of no internal crack defects under specific laser power, scanning speed, and scanning layer thickness. min ; S2: Based on the critical scanning spacing h min Determine the value range of the scanning spacing h for additive manufacturing.

2. The additive manufacturing method based on molten pool control according to claim 1, characterized in that: In step S2, the range of the scanning spacing h for additive manufacturing is determined to satisfy: h ≥ h min .

3. The additive manufacturing method based on molten pool control according to claim 2, characterized in that: Step S1 includes: S101: Obtaining value ranges of process parameters laser power P, scanning speed v, and scanning layer thickness t based on statistical analysis; S102: The scanning interval h is set to values ​​h1, h2, ..., h i , the corresponding samples are obtained by additive manufacturing under the same conditions within the process parameter value range obtained in S101, where i is the sequence number and h is the i is the scanning interval of the i-th sequence number, h1~h i Increase successively; S103: Perform metallographic analysis on the sample, and select the minimum value of the scanning spacing h among the samples that meet the requirement of no internal crack defect as the critical scanning spacing h min .

4. The additive manufacturing method based on molten pool control according to claim 3, characterized in that: The additive manufacturing method based on molten pool regulation also includes: optimizing process parameters based on the matching relationship between the morphology of the molten pool and the additive manufacturing parameters.

5. The additive manufacturing method based on molten pool control according to claim 4, characterized in that: The morphological parameters of the molten pool include: molten pool depth D and molten pool width W.

6. The additive manufacturing method based on molten pool control according to claim 5, characterized in that: The additive manufacturing method based on molten pool regulation also includes: S3: Optimize the scanning spacing h based on the molten pool width W and the molten pool depth D.

7. The additive manufacturing method based on molten pool control according to claim 6, characterized in that: Step S3 includes: S301: Obtaining a first upper limit value h1 of the scanning spacing h based on the molten pool depth D; S302: Obtaining a second upper limit value h3 of the scanning spacing h based on the molten pool width W; S303: Compare h1 and h3, and take the smaller one as the maximum value h of the scanning interval h max ; S304: Scanning interval h satisfies: h min ≤h≤h max .

8. The additive manufacturing method based on molten pool control according to claim 7, characterized in that: In S301, the first upper limit h1 of the scanning spacing h obtained based on the molten pool depth D satisfies: When the molten pool depth D = scanning layer thickness t, the corresponding scanning spacing h value is h1.

9. The additive manufacturing method based on molten pool control according to claim 7, characterized in that: In S302, the second upper limit value h3 of the scanning spacing h obtained based on the molten pool width W satisfies: When the molten pool width W = scanning spacing h, the corresponding scanning spacing h value is h3.

10. A high temperature nickel-based alloy additive manufacturing product, characterized in that: Prepared by the additive manufacturing method according to any one of claims 1 to 9.

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