Process control method for realizing harmlessness of oxide in additive manufacturing

Abstract

The invention provides a process control method for realizing harmlessness of oxide in additive manufacturing, which belongs to the field of laser additive manufacturing, and comprises the following steps of: smelting by adopting a vacuum induction and vacuum self-consumption process to obtain a master alloy, forging the master alloy into a bar, and performing gas atomization powder preparation; carrying out additive manufacturing by adopting a laser melting deposition technology to obtain a printed piece; and on the basis of the first-time melting, the printed piece is remelted, and the alloy part is obtained. By adopting a laser melting deposition technology, the average size of the oxide is reduced from greater than or equal to 2 mu m to less than or equal to 1 mu m, and the adverse effect of the oxide on the material performance is remarkably reduced. The oxide is more uniformly distributed in the matrix, and the stress concentration caused by local enrichment is avoided. By means of the optimized technology, the tensile strength of the material is improved to 1000 MPa or above, the ductility is improved to 17.8%, and meanwhile the crack sensitivity is remarkably reduced.

Description

Technical Field

[0001] The present invention belongs to the field of laser additive manufacturing, and particularly relates to a process control method for realizing harmless treatment of oxides in additive manufacturing. Background Art

[0002] Additive manufacturing technology, with the characteristics of short manufacturing cycle, near-net shaping, excellent mechanical properties, strong structural adaptability, and large design freedom, has obvious advantages in the forming of complex and precision structures and difficult-to-machine material components compared with traditional processes. Moreover, it can process a variety of metals, such as aluminum alloys, titanium alloys, stainless steels, high-entropy alloys and other alloys, and is widely used due to its good processing performance and high reliability. As one of the core technologies of additive manufacturing, the powder bed melting technology has become an important part of modern manufacturing industry with its high precision and high material utilization rate.

[0003] The Fe-Cr-Ni-Co-Mo system is a new type of maraging stainless steel, which realizes the coordinated improvement of high strength and excellent toughness through alloying design. This material exhibits a unique dual strengthening mechanism after heat treatment: on the one hand, the matrix is strengthened by martensitic transformation, and on the other hand, age hardening is achieved by the precipitation of intermetallic compounds (such as Ni3Ti, Fe2Mo, etc.). However, due to the high degree of alloying in this system, significant oxide inclusion problems are faced during the additive manufacturing process: oxides with larger sizes (such as Al2O3, SiO2, complex oxides, etc.) are likely to form at the bottom of the molten pool, which is mainly attributed to the complex influence of high alloy composition on the fluidity and solidification behavior of the molten pool. These oxides not only reduce the density of the material, but also become the starting point for crack propagation, seriously affecting the mechanical properties and service life of the parts.

[0004] At present, the maturity of the additive manufacturing process of this material has not reached the industrial application level, and it is urgent to optimize the printing parameters to achieve precise control of the oxide size and distribution, so as to improve the density and mechanical properties of the parts. Summary of the Invention

[0005] Aiming at the needs of fields such as aerospace, and aiming at the serious problem of oxides in the new type of maraging steel, the present invention provides a process control method for realizing harmless treatment of oxides in additive manufacturing, that is, by adjusting process parameters to control oxides, microstructure and mechanical properties, and good control effects have been obtained.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A process control method for realizing harmless treatment of oxides in additive manufacturing, comprising the following steps:

[0008] (1) Smelt the master alloy by vacuum induction and vacuum consumable processes, forge the master alloy into bars and atomize the powder by gas atomization;

[0009] (2) An additive manufacturing is carried out by using a laser melting deposition technique to obtain a printed part;

[0010] (3) On the basis of the first melting, the printed part is remelted to obtain an alloy part.

[0011] Preferably, in step (1), the mass percentage contents of the components in the master alloy are as follows: C: 0.001 - 0.003 wt.%, Cr: 10.5 - 12.0 wt.%, Ni: 7.5 - 9.0 wt.%, Co: 4.0 - 5.5 wt.%, Mo: 1.8 - 2.2 wt.%, V: 0.01 - 0.03 wt.%, Ti: 0.02 - 0.2 wt.%, Al: 0.06 - 0.16 wt.%, Si: 0.1 - 0.2 wt.%, Mn: 0.1 - 0.7 wt.%, S: 0.001 - 0.002 wt.%, P: 0.001 - 0.002 wt.%, O: 900 ppm, N ≤ 40 ppm, H ≤ 2 ppm, and the balance is Fe. This alloy system is the Fe-Cr-Ni-Co-Mo maraging stainless steel mentioned in the background art.

[0012] Preferably, in step (1), after gas atomization powder making, the powder with a particle size D50 of 15 - 53 μm is collected. The oxygen content in the master alloy and the collected powder in the present invention is 900 ppm. Using the powder in a high oxygen state is convenient for studying the oxide problem in the printed part.

[0013] Preferably, in step (2), the parameters of the first laser melting deposition are: laser power 100 - 250 W, scanning speed 600 - 1000 mm / s, scanning spacing 70 - 80 μm, powder layer thickness 30 μm, and the volumetric energy density is 69 - 108 J / mm 3 The first melting is carried out to ensure the stability of the molten pool and preliminary densification.

[0014] Preferably, in step (3), the parameters of the laser melting deposition for remelting are: laser power 120 - 250 W, scanning speed 500 - 1100 mm / s, scanning spacing 70 - 80 μm, and the volumetric energy density is 70 - 100 J / mm 3 , promoting the dissolution and uniform distribution of oxides.

[0015] When using the remelting strategy, the changes in the first and second printing parameters are mainly to optimize the melting and solidification behavior of the molten pool. The first laser melting deposition needs to ensure that the powder is completely melted and a dense layer is formed, generally with a large energy input. Remelting requires a lower laser power and a faster printing scanning speed than the first laser melting, which can also refine the grains and optimize the microstructure. Among them, the laser power, scanning speed, and scanning spacing are key parameters. The volumetric energy density can be the same or different, and the formula for calculating the volumetric energy density is laser power / (scanning speed × scanning spacing × powder layer thickness).

[0016] Preferably, in steps (2) and (3), during the first melting and remelting processes, a rotational angle of 67° cross-rotational scanning is used. This can effectively avoid the aggregation of oxides in a single direction and improve the fluidity of the molten pool and the uniformity of the microstructure.

[0017] Preferably, in steps (2) and (3), 99.9% high-purity argon is used as the shielding gas to reduce the oxygen content to less than 100 ppm to avoid the formation of oxides.

[0018] Furthermore, the alloy parts obtained in step (3) do not require subsequent heat treatment.

[0019] The present invention also provides alloy parts prepared by the described method. The mass percentage content of oxides in the alloy parts is less than 0.1 wt.%, which can endow the material with good mechanical properties and fatigue resistance. Moreover, the oxides do not form large-size inclusions, and their sizes are small and distributed in a dispersed state, and their contribution to strength is similar to that of second-phase particle strengthening, which is overall beneficial to the improvement of performance.

[0020] Compared with the prior art, the present invention has the following remarkable advantages:

[0021] The present invention uses the laser melting deposition technology. After obtaining an alloy printed part by additive manufacturing, a laser remelting strategy is adopted to reduce the average size of oxides from ≥2 μm to ≤1 μm, significantly reducing the adverse effects of oxides on the material properties. It makes the distribution of oxides in the matrix more uniform and avoids stress concentration caused by local enrichment. The optimized process increases the tensile strength of the material to above 1000 MPa, the elongation rate is increased to 17.8%, and at the same time, the crack sensitivity is significantly reduced.

[0022] The laser remelting process control method provided by the present invention is not only applicable to maraging steel but also can be extended to the additive manufacturing of other high-alloyed materials, and is expected to significantly improve the manufacturing quality and service performance of complex parts. Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 It is a scanning electron microscope image of the high-oxygen-content powder of the novel maraging stainless steel Fe-Cr-Ni-Co-Mo obtained after gas atomization powder making in Example 1.

[0025] Figure 2(a) is a microstructural diagram of the interior of the melt pool of the printed part obtained by the first melting in Example 1.

[0026] Figure 2(b) is a microstructural diagram of the interior of the melt pool of the printed sample obtained after remelting in Example 1.

[0027] Figure 3 It is an X-ray diffraction analysis diagram of the finally obtained printed samples in Examples 1-4.

[0028] Figure 4(a) is a microstructural diagram of the oxides inside the single-pass printed sample in Example 1.

[0029] Figure 4(b) is a microstructural diagram of the oxides of the sample after remelting in Example 1.

[0030] Figure 5 It is a room-temperature tensile curve diagram of the finally obtained printed sample in Example 1. Detailed implementation manners

[0031] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the drawings and specific embodiments.

[0032] Example 1

[0033] This example provides a novel maraging stainless steel Fe-Cr-Ni-Co-Mo, and the process control method for realizing harmless oxides in additive manufacturing is as follows:

[0034] (1) The mass percentages of the components of the powder material used are as follows: C: 0.002 wt.%, Cr: 10.5 wt.%, Ni: 8.2 wt.%, Co: 4.5 wt.%, Mo: 1.8 wt.%, V: 0.02 wt.%, Ti: 0.02 wt.%, Al: 0.16 wt.%, Si: 0.2 wt.%, Mn: 0.3 wt.%, S: 0.002 wt.%, P: 0.002 wt.%, O: 900 ppm, N≤40 ppm, H≤2 ppm, and the balance is Fe.

[0035] (2) The Fe-Cr-Ni-Co-Mo new maraging stainless steel powder is dried in a vacuum drying oven before printing. The temperature of the vacuum drying oven is 90 °C and the time is 8 hours. Figure 1 Fig. Figure 1 is the SEM image of the Fe-Cr-Ni-Co-Mo new maraging stainless steel powder with high oxygen content obtained after gas atomization powder making in Example 1. It can be seen that the surface of the powder is severely oxidized, a large amount of oxides are enriched on the surface of the powder, and the surface of some powders is deformed, which will have an adverse effect on the performance of the printed parts.

[0036] (3) The sliced file is pre-processed, the printing parameters are set, and the dried powder is loaded into a selective laser melting printer, evacuated and waiting for printing.

[0037] (4) The specific printing parameters are as follows: for the first melting: laser power 100W, scanning speed 500mm / s, scanning spacing 80μm, powder layer thickness 30μm, rotation angle 67°, energy density 83.33J / mm 3 , and the process parameters for the second remelting are: laser power 100W, scanning speed 900mm / s, scanning spacing 70μm, rotation angle 67°, energy density 52.91J / mm 3 .

[0038] (5) After printing, surface sandblasting treatment is carried out. The prepared sample is separated from the substrate by mechanical wire cutting, cleaned with anhydrous ethanol and dried. SEM, EBSD, and TEM are used to observe the types, sizes, and distributions of oxides on small piece of metallographic specimens.

[0039] Fig. 2(a) is the microstructural diagram of the molten pool inside the printed part obtained by the first melting in Example 1. Obvious defects are observed at the bottom of the molten pool, which are caused by oxides and affect the Marangoni convection. Fig. 2(b) is the microstructural diagram of the molten pool inside the printed sample obtained after remelting in Example 1, and its surface is flat without obvious defects.

[0040] Figure 3 Fig. is the X-ray diffraction analysis diagram of the finally prepared printed samples in Examples 1-4, indicating that the alloy phases of the above samples are all martensite phases.

[0041] Fig. 4(a) is the microstructural diagram of the oxides inside the single-print sample in Example 1. Fig. 4(b) is the microstructural diagram of the oxides of the sample after remelting in Example 1. Comparing Fig. 4(a) and Fig. 4(b), it shows that the size of the oxides becomes nanoscale oxides after remelting.

[0042] (6) Process into standard tensile specimens according to the standard drawing of GB / T 228.1-2021 for mechanical property testing, and conduct microstructural analysis on the tensile fracture surface. Figure 5The room temperature tensile curve of the printed sample finally obtained in Example 1, with a tensile rate of 0.5 mm / min. Compared with the sample printed once, the yield strength and tensile strength of the remelted sample are almost unchanged, and the elongation rate is improved. Therefore, the adverse effect of nanoscale oxides on plasticity is very small.

[0043] The size of the oxides in the sample prepared in Example 1 is ≤1 μm, and there is almost no oxide aggregation at the bottom of the molten pool. The room temperature tensile properties obtained are: yield strength: 700 MPa, tensile strength 998 MPa, and elongation rate of 17.8%.

[0044] Example 2

[0045] This example provides a new type of maraging stainless steel of Fe-Cr-Ni-Co-Mo, and the process control method for realizing harmless oxides in additive manufacturing is as follows:

[0046] (1) The mass percentages of the components of the powder material used are as follows: C: 0.002 wt.%, Cr: 10.5 wt.%, Ni: 8.2 wt.%, Co: 4.5 wt.%, Mo: 1.8 wt.%, V: 0.02 wt.%, Ti: 0.02 wt.%, Al: 0.16 wt.%, Si: 0.2 wt.%, Mn: 0.3 wt.%, S: 0.002 wt.%, P: 0.002 wt.%, O: 900 ppm, N≤40 ppm, H≤2 ppm, and the balance is Fe.

[0047] (2) For the powder of the new type of maraging stainless steel of Fe-Cr-Ni-Co-Mo, it is dried in a vacuum drying oven before printing. The temperature of the vacuum drying oven is 90 °C and the time is 8 hours.

[0048] (3) Pretreat the slicing file well, set the printing parameters, load the dried powder into a selective laser melting printer, evacuate and wait for printing.

[0049] (4) The specific printing parameters are as follows: for the first melting: laser power 100 W, scanning speed 600 mm / s, scanning spacing 80 μm, powder layer thickness 30 μm, rotation angle 67°, and energy density 69.44 J / mm 3 , and the process parameters for the second remelting are: laser power 150 W, scanning speed 600 mm / s, scanning spacing 80 μm, rotation angle 67°, and energy density 104.17 J / mm 3 .

[0050] (5) After printing, perform surface sandblasting treatment, separate the prepared sample from the substrate by mechanical wire cutting, clean it with anhydrous ethanol and blow it dry, and observe the types, sizes and distributions of oxides on small block metallographic specimens by SEM, EBSD and TEM.

[0051] (6) Process according to the standard drawing of GB / T 228.1-2021 to make standard tensile specimens for mechanical property testing, and conduct microscopic structure analysis on the tensile fracture surface.

[0052] For the sample obtained in Example 2, the size of the oxide is ≤1μm, and there is almost no oxide aggregation at the bottom of the molten pool. The tensile properties at room temperature obtained are: yield strength: 694 MPa, tensile strength: 978 MPa, and elongation: 17.6%.

[0053] Example 3

[0054] This example provides a new type of maraging stainless steel of Fe-Cr-Ni-Co-Mo, and the process control method for realizing harmless oxides in additive manufacturing is as follows:

[0055] (1) The mass percentages of each component of the powder material used are as follows: C: 0.002 wt.%, Cr: 10.5 wt.%, Ni: 8.2 wt.%, Co: 4.5 wt.%, Mo: 1.8 wt.%, V: 0.02 wt.%, Ti: 0.02 wt.%, Al: 0.16 wt.%, Si: 0.2 wt.%, Mn: 0.3 wt.%, S: 0.002 wt.%, P: 0.002 wt.%, O: 900 ppm, N≤40 ppm, H≤2 ppm, and the balance is Fe.

[0056] (2) For the powder of the new type of maraging stainless steel of Fe-Cr-Ni-Co-Mo, dry it in a vacuum drying oven before printing. The temperature of the vacuum drying oven is 90°C and the time is 8 hours.

[0057] (3) Pretreat the slice file in advance, set the printing parameters, load the dried powder into a selective laser melting printer, evacuate and wait for printing.

[0058] (4) The specific printing parameters are as follows for the first melting: laser power 100W, scanning speed 600mm / s, scanning spacing 80μm, powder spreading layer thickness 30μm, rotation angle 67°, and energy density 69.44J / mm 3 , and the process parameters for the second remelting are: laser power 150W, scanning speed 900mm / s, scanning spacing 70μm, rotation angle 67°, and energy density 69.44J / mm 3 .

[0059] After printing, conduct surface sandblasting treatment, separate the prepared sample from the substrate by mechanical wire cutting, clean it with anhydrous ethanol and blow it dry, and observe the types, sizes and distributions of oxides of small piece metallographic specimens by SEM, EBSD, and TEM.

[0060] (6) Processed into standard tensile specimens according to the GB / T 228.1-2021 standard drawing for mechanical property testing, and conduct microstructure analysis on the tensile fracture surface.

[0061] The size of the oxide in the sample prepared in Example 3 is ≤1μm, and there is almost no oxide aggregation at the bottom of the molten pool. The tensile properties at room temperature obtained are: yield strength: 724 MPa, tensile strength 1002 MPa, and elongation of 17.3%.

[0062] Example 4

[0063] This example provides a new type of Fe-Cr-Ni-Co-Mo maraging stainless steel, and the process control method for realizing the harmlessness of oxides in additive manufacturing is as follows:

[0064] (1) The mass percentages of each component of the powder material used are as follows: C: 0.002 wt.%, Cr: 10.5 wt.%, Ni: 8.2 wt.%, Co: 4.5 wt.%, Mo: 1.8 wt.%, V: 0.02 wt.%, Ti: 0.02 wt.%, Al: 0.16 wt.%, Si: 0.2 wt.%, Mn: 0.3 wt.%, S: 0.002 wt.%, P: 0.002 wt.%, O: 900 ppm, N≤40 ppm, H≤2 ppm, and the balance is Fe.

[0065] (2) For the powder of the new type of Fe-Cr-Ni-Co-Mo maraging stainless steel, dry it in a vacuum drying oven before printing. The temperature of the vacuum drying oven is 90°C and the time is 8 hours.

[0066] (3) Pretreat the slice file well, set the printing parameters, load the dried powder into a selective laser melting printer, evacuate and wait for printing.

[0067] (4) The specific printing parameters are as follows for the first melting: laser power 200W, scanning speed 800mm / s, scanning spacing 80μm, powder spreading layer thickness 30μm, rotation angle 67°, and energy density of 104.17J / mm 3 , and the process parameters for re-melting are: laser power 100W, scanning speed 600mm / s, scanning spacing 70μm, rotation angle 67°, and energy density of 69.44J / mm 3 .

[0068] After printing, conduct surface sandblasting treatment, separate the prepared sample from the substrate by mechanical wire cutting, clean it with anhydrous ethanol and blow it dry, and observe the types, sizes and distributions of oxides on small piece metallographic specimens by SEM, EBSD and TEM.

[0069] (6) Processed into standard tensile specimens according to the standard drawing of GB / T 228.1-2021 for mechanical property testing, and the tensile fracture was analyzed for its microstructure.

[0070] For the sample prepared in Example 4, the size of the oxide is ≤1μm, and there is almost no oxide aggregation at the bottom of the molten pool. The tensile properties at room temperature obtained are: yield strength: 761 MPa, tensile strength: 1105 MPa, and elongation: 16.9%.

[0071] Comparative Example 1

[0072] This comparative example provides a sample of a new type of maraging stainless steel of Fe-Cr-Ni-Co-Mo after heat treatment after printing. The specific method is as follows:

[0073] (1) The mass percentages of the components of the powder material used are as follows: C: 0.002 wt.%, Cr: 10.5 wt.%, Ni: 8.2 wt.%, Co: 4.5 wt.%, Mo: 1.8 wt.%, V: 0.02 wt.%, Ti: 0.02 wt.%, Al: 0.16 wt.%, Si: 0.2 wt.%, Mn: 0.3 wt.%, S: 0.002 wt.%, P: 0.002 wt.%, O: 900 ppm, N≤40 ppm, H≤2 ppm, and the balance is Fe.

[0074] (2) The powder of the new type of maraging stainless steel of Fe-Cr-Ni-Co-Mo was dried in a vacuum drying oven before printing. The temperature of the vacuum drying oven was 90 °C and the time was 8 hours.

[0075] (3) The sliced file was pre-treated, the printing parameters were set, and after the powder was dried, it was loaded into a selective laser melting printer, and the vacuum was pumped and waited for printing.

[0076] (4) This comparative example used one-time laser printing. The specific printing parameters were: laser power 200 W, scanning speed 800 mm / s, scanning spacing 80 μm, powder spreading layer thickness 30 μm, rotation angle: 67°, and energy density 104.17 J / mm 3 .

[0077] After printing, surface sandblasting treatment was carried out. The prepared sample was separated from the substrate by mechanical wire cutting, cleaned with anhydrous ethanol and dried. The sample was further heat-treated. The heating rate of the sample heat treatment was 5 °C / min, heated to 450 °C, held for 240 min, and then air-cooled to room temperature.

[0078] (6) Processed into standard tensile specimens according to the standard drawing of GB / T 228.1-2021 for mechanical property testing, and the tensile fracture was analyzed for its microstructure.

[0079] In Comparative Example 1, oxides were still found inside the sample. The size of the oxides was 1 - 2 μm. The room-temperature tensile properties obtained after heat treatment were as follows: yield strength 914 MPa, tensile strength 1160 MPa, and elongation 20.1%. Comparative Example 1 is an example of heat treatment after single laser remelting. Its mechanical properties were slightly higher than those of the examples due to the presence of precipitation phases. The increase in tensile strength was because during the heat treatment process, nano metal intermetallic compound precipitation strengthening occurred during aging. The increase in elongation was because the presence of reversed austenite during aging increased the elongation. However, there were still oxide inclusions with relatively large sizes inside, and the size and distribution of the oxides did not change due to aging heat treatment.

[0080] Comparative Example 2

[0081] This comparative example provides a novel maraging stainless steel of Fe-Cr-Ni-Co-Mo by normal laser printing. The specific method is as follows:

[0082] (1) The mass percentages of the components of the powder material used are as follows: C: 0.002 wt.%, Cr: 10.5 wt.%, Ni: 8.2 wt.%, Co: 4.5 wt.%, Mo: 1.8 wt.%, V: 0.02 wt.%, Ti: 0.02 wt.%, Al: 0.16 wt.%, Si: 0.2 wt.%, Mn: 0.3 wt.%, S: 0.002 wt.%, P: 0.002 wt.%, O: 900 ppm, N ≤ 40 ppm, H ≤ 2 ppm, and the balance is Fe.

[0083] (2) The powder of the novel maraging stainless steel of Fe-Cr-Ni-Co-Mo was dried in a vacuum drying oven before printing. The temperature of the vacuum drying oven was 90 °C and the time was 8 hours.

[0084] (3) The slice file was pre-processed and the printing parameters were set. After the powder was dried, it was loaded into a selective laser melting printer, and the vacuum was pumped and waited for printing.

[0085] (4) This comparative example used single laser printing. The specific printing parameters were: laser power 200 W, scanning speed 800 mm / s, scanning spacing 80 μm, powder layer thickness 30 μm, rotation angle: 67°, and energy density 104.17 J / mm 3 .

[0086] After printing was completed, surface sandblasting treatment was carried out. The prepared sample was separated from the substrate by mechanical wire cutting, washed with anhydrous ethanol and dried. SEM, EBSD, and TEM were used to observe the types, sizes, and distributions of oxides on small piece metallographic specimens.

[0087] (6) Process it into a standard tensile specimen according to the standard drawing of GB / T 228.1-2021 for mechanical property testing, and conduct microstructure analysis on the tensile fracture surface.

[0088] For the sample prepared in Comparative Example 2, the size of the oxide is ≥2 μm, and there is oxide aggregation at the bottom of some molten pools. The obtained room-temperature tensile properties are: yield strength: 694 MPa, tensile strength: 968 MPa, and elongation: 14.9%. Comparative Example 2 is an example of single-pass laser remelting. Compared with the examples, due to the presence of oxide inclusions and the fact that the oxide size is not nanoscale, the elongation is lower than that of the examples.

[0089] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A process control method for realizing harmless treatment of oxides in additive manufacturing, characterized in that, It includes the following steps: (1) The master alloy is smelted by vacuum induction and vacuum consumable processes, and the master alloy is forged into bars for gas atomization powder making; (2) Using laser melting deposition technology to perform additive manufacturing to obtain a printed part; (3) On the basis of the first melting, the printed part is remelted to obtain an alloy part.

2. The process control method for realizing harmless treatment of oxides in additive manufacturing according to claim 1, characterized in that, In step (1), the mass percentage content of each component in the master alloy is: C: 0.001 - 0.003 wt.%, Cr: 10.5 - 12.0 wt.%, Ni: 7.5 - 9.0 wt.%, Co: 4.0 - 5.5 wt.%, Mo: 1.8 - 2.2 wt.%, V: 0.01 - 0.03 wt.%, Ti: 0.02 - 0.2 wt.%, Al: 0.06 - 0.16 wt.%, Si: 0.1 - 0.2 wt.%, Mn: 0.1 - 0.7 wt.%, S: 0.001 - 0.002 wt.%, P: 0.001 - 0.002 wt.%, O: 900 ppm, N ≤ 40 ppm, H ≤ 2 ppm, and the balance is Fe.

3. The process control method for realizing harmless treatment of oxides in additive manufacturing according to claim 2, wherein, In step (1), after gas atomization powder making, the powder with a particle size D50 of 15 - 53 μm is collected.

4. The process control method for realizing harmless treatment of oxides in additive manufacturing according to claim 3, characterized in that, In step (2), the parameters of the first laser melting deposition are as follows: laser power is 100 - 250 W, scanning speed is 600 - 1000 mm / s, scanning pitch is 70 - 80 μm, powder layer thickness is 30 μm, and the volumetric energy density is 69 - 108 J / mm 3 .

5. The process control method for realizing harmless treatment of oxides in additive manufacturing according to claim 4, characterized in that, In step (3), the laser melting deposition parameters for remelting are as follows: laser power is 120 - 250 W, scanning speed is 500 - 1100 mm / s, scanning pitch is 70 - 80 μm, and the volumetric energy density is 70 - 100 J / mm 3 .

6. The process control method for realizing harmless treatment of oxides in additive manufacturing according to claim 5, wherein, In steps (2) and (3), during the first melting and remelting processes, a rotational angle of 67° cross-rotational scanning is used.

7. The process control method for realizing harmless treatment of oxides in additive manufacturing according to claim 6, characterized in that In steps (2) and (3), 99.9% high-purity argon gas is used as the shielding gas.

8. The process control method for realizing harmless treatment of oxides in additive manufacturing according to claim 7, characterized in that The alloy part obtained in step (3) does not require subsequent heat treatment.

9. An alloy part prepared by the method according to any one of claims 1 to 8.

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