Maraging steel and additive manufacturing method thereof

Abstract

The application discloses a kind of maraging steels and its additive manufacturing method, belong to alloy material technical field, is prepared using additive manufacturing method, with percentage by weight, the maraging steel includes: 0.03%-0.15% of C, 17.0%-22.0% of Ni, 2.0%-6.5% of Al and 0.05%-0.25% of Nb, the balance is Fe.The maraging steel in the application does not contain noble metal element, and the strength of maraging steel is maintained by element ratio, realizes the technical effect of reducing the preparation cost of maraging steel in additive manufacturing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alloy materials, in particular to a maraging steel and an additive manufacturing method thereof. BACKGROUND

[0002] The maraging steel has the advantages of high strength, high ductility, good hardenability and good welding performance, and is widely used in the fields of aerospace, military industry, mold and the like. However, the maraging steel component manufactured by the traditional method often has problems of complex process and procedure, large forming technology difficulty, low material utilization rate and high manufacturing cost, which restricts the further development and application of the maraging steel structural component. The laser additive manufacturing technology can realize the near-net forming of high-performance complex metal components, and gradually becomes an important way for preparing the maraging steel parts.

[0003] At present, the maraging steels commonly used for additive manufacturing, such as 18Ni(200), 18Ni(250), 18Ni(300), 18Ni(350) and the like traditional Fe-Ni-based maraging steels, all contain Co, Mo and other noble metal elements. Due to the shortage of Co and Mo elements and the continuous rise in price, the preparation cost of the maraging steel is high. SUMMARY

[0004] The main purpose of the present application is to provide a maraging steel and an additive manufacturing method thereof, aiming at solving the problem of high preparation cost of the maraging steel applied to the additive manufacturing method.

[0005] To achieve the above-mentioned purpose, the present application provides a maraging steel prepared by an additive manufacturing method, which comprises, by weight percentage, 0.03%-0.15% of C, 17.0%-22.0% of Ni, 2.0%-6.5% of Al and 0.05%-0.25% of Nb, and the balance of Fe.

[0006] Optionally, the maraging steel further comprises 0.10%-0.30% of Mn.

[0007] Optionally, the maraging steel further comprises 0.0008%-0.003% of B.

[0008] In addition, to achieve the above-mentioned purpose, the present application further provides an additive manufacturing method of a maraging steel, which is used for preparing the maraging steel as described above, and comprises the following steps:

[0009] Taking the raw materials of each element by weight percentage, the raw materials are gas atomized to prepare spherical powders;

[0010] The spherical powders are subjected to laser additive manufacturing treatment to obtain a preform.

[0011] subjecting the preform to a heat treatment to obtain the maraging steel.

[0012] Optionally, the particle size of the spherical powder is 10-200 μm.

[0013] Optionally, the step of subjecting the spherical powder to a laser additive manufacturing treatment to obtain a preform comprises:

[0014] obtaining a three-dimensional model of the maraging steel;

[0015] subjecting the three-dimensional model to a slicing treatment to obtain slice layer parameters of a plurality of slice layers;

[0016] depositing the spherical powder into a powder layer according to the slice layer parameters;

[0017] subjecting the powder layer to a powder bed laser fusion forming to obtain the preform.

[0018] Optionally, the control parameters of the powder bed laser fusion forming comprise: a laser power of 150-300 W, a scanning speed of 800-1500 mm / s, a scanning interval of 50-120 μm, and a powder layer thickness of 30-110 μm.

[0019] Optionally, the step of subjecting the spherical powder to a laser additive manufacturing treatment to obtain a preform comprises:

[0020] obtaining a three-dimensional model of the maraging steel;

[0021] planning a plurality of scanning paths according to the three-dimensional model;

[0022] subjecting the spherical powder to a direct energy deposition forming according to the scanning paths to obtain the preform.

[0023] Optionally, the control parameters of the direct energy deposition forming comprise: a laser power of 1.0-2.0 kW, a scanning speed of 500-1000 mm / s, a single layer thickness of laser cladding of 0.8-1.2 mm, a powder feeding gas flow of 1-2 L / min, and a protective gas beam diameter of 5 mm, the protective gas beam being centered on the laser beam and moving with the laser beam, and a flow rate of 1-5 L / min.

[0024] Optionally, the heat treatment is a direct aging heat treatment, the aging temperature of the direct aging heat treatment is 480-550 °C, the holding time of the direct aging heat treatment is 1-5 h, and the cooling mode of the direct aging heat treatment is air cooling.

[0025] The martensitic age hardening steel prepared by the additive manufacturing method provided by the application comprises, in percentage by weight, 0.03%-0.15% of C, 17.0%-22.0% of Ni, 2.0%-6.5% of Al and 0.05%-0.25% of Nb, and the balance is Fe. Through the above element ratio, the NiAl phase and the NbC phase are synergistically precipitated in the high dislocation density martensitic matrix, so that the super-high strength and good toughness are obtained, the use performance of the martensitic age hardening steel as a structural part is maintained, the raw material cost is reduced due to the absence of the noble metal elements Co and Mo, the preparation cost of the martensitic age hardening steel can also be reduced, and different strength and toughness combinations can be obtained by adjusting the element composition ratio and the heat treatment process, so as to meet the demand for the mechanical properties of the structural part in different application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a flowchart of the first embodiment of the additive manufacturing method of the martensitic age hardening steel of the application;

[0027] Figure 2 It is a physical diagram of the martensitic age hardening steel prepared in Example 1 of the application;

[0028] Figure 3 It is a stress-strain curve diagram of the martensitic age hardening steel prepared in Example 1 of the application;

[0029] Figure 4 It is a physical diagram of the martensitic age hardening steel prepared in Example 2 of the application;

[0030] Figure 5 It is an electron backscattering diagram of the martensitic age hardening steel prepared in Example 2 of the application.

[0031] The implementation, functional features and advantages of the application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0032] It should be understood that the specific embodiments described herein are only used to explain the application and not to limit the application.

[0033] The martensitic age hardening steel has the advantages of super-high strength, high ductility, good hardenability and good welding performance, and is widely used in the fields of aerospace, military industry, mold and the like. However, the traditional method for manufacturing the martensitic age hardening steel component often has the problems of complex process and procedure, large forming technical difficulty, low material utilization rate and high manufacturing cost, which restricts the further development and application of the martensitic age hardening steel structural part. In recent years, with the rapid development of laser additive manufacturing technology, such as powder bed laser fusion technology and direct energy deposition technology, the near-net forming of high-performance complex metal components can be realized, and gradually becomes an important way for preparing the martensitic age hardening steel parts.

[0034] The martensitic age hardening steels currently used for laser additive manufacturing, such as 18Ni(200), 18Ni(250), 18Ni(300), 18Ni(350) and the like traditional Fe-Ni based martensitic age hardening steels, are obtained by adjusting the contents of Co (8.5-12.5wt%), Mo (3.5-5wt%) and Ti (0.2-1.6wt%) to obtain different strength levels. However, due to the shortage of Co and Mo elements and the continuous rise in price, the cost of raw materials is rising. In addition, the strength of the traditional martensitic age hardening steel such as 18Ni(300) used for additive manufacturing can reach 2GPa, but the elongation is only about 4%, which leads to the easy initiation of cracks and the fatigue performance cannot reach the level of forged materials. The application range of the existing additive manufacturing parts based on traditional martensitic age hardening steel is greatly limited, so it is of great significance to develop low-cost ultra-high strength martensitic age hardening steel suitable for additive manufacturing and additive manufacturing process based thereon.

[0035] The embodiment of the present application provides a kind of martensitic age hardening steel, is prepared by additive manufacturing method, martensitic age hardening steel includes: 0.03%-0.15% of C, 17.0% -22.0% of Ni, 2.0% -6.5% of Al and 0.05% -0.25% of Nb, the balance is Fe by weight percentage.

[0036] The addition amount of C element in the martensitic age hardening steel is in the range of 0.03%-0.15%, for example, 0.03%, 0.06%, 0.09%, 0.12%, 0.15%. The martensitic age hardening steel is strengthened by the dispersion of intermetallic compounds, and generally, C element is considered as a harmful element in the martensitic age hardening steel, and the content of C element is controlled in the smallest range. In the embodiment, C element and Nb element form NbC phase precipitation to improve the strength. In addition, C element can also promote the formation of martensite and increase the solid solution strengthening effect of martensite matrix.

[0037] The addition amount of Ni element in the martensitic age hardening steel is in the range of 17.0%-22.0%, for example, 17.0%, 17.5%, 18.0%, 18.5%, 19.0%, 19.5%, 20.0%, 20.5%, 21.0%, 21.5%, 22.0%. Ni element is a widely used element in the martensitic age hardening steel, which can form NiAl phase precipitation with Al element to improve the strength of the martensitic age hardening steel.

[0038] The addition amount of Al element in the maraging steel is in the range of 2.0%-6.5%, for example, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%. The Al element can reduce the density of the matrix, form a NiAl phase with the Ni element, and improve the strength of the maraging steel.

[0039] The addition amount of Nb element in the maraging steel is in the range of 0.05%-0.25%, for example, 0.05%, 0.10%, 0.15%, 0.20%, 0.25%. The Nb element and the C element form a NbC phase, the NbC phase belongs to the NaCl type cubic system, and the hardness is high, which can hinder the movement of dislocations in the maraging steel.

[0040] In some possible embodiments, on the basis of the element composition of the above maraging steel, Mn in the range of 0.10%-0.30% by weight, for example, 0.1%, 0.15%, 0.20%, 0.25%, 0.30% can also be added. The addition of the Mn element can enhance the toughness of the maraging steel.

[0041] In some possible embodiments, on the basis of the element composition of the above maraging steel, B in the range of 0.0008%-0.003% by weight, for example, 0.0008%, 0.0012%, 0.0016%, 0.002%, 0.0024%, 0.003% can also be added. The B element can refine the grains and further improve the strength of the maraging steel.

[0042] Through the selection and matching of the above elements, the NiAl phase and the NbC phase are synergistically precipitated in the supersaturated martensite to hinder the movement of dislocations and thus improve the strength of the material. In addition, a small amount of residual austenite existing in the matrix can also play a role in improving the elongation of the material. The cost is reduced by half compared with the traditional maraging steel 18Ni300, the strength remains at the same level, and the elongation is doubled. By adjusting the composition ratio and the heat treatment process, different strength and toughness combinations can be obtained to meet the demand for mechanical properties in different application scenarios.

[0043] The embodiment of the present application provides a maraging steel additive manufacturing method, referring to Figure 1 , Figure 1 The embodiment of the present application provides a maraging steel additive manufacturing method, referring to

[0044] In the embodiment, the additive manufacturing method of the maraging steel comprises the following steps.

[0045] In step S10, the raw materials of each element are taken according to the weight percentage, and the raw materials are prepared into spherical powder by gas atomization.

[0046] The raw materials of the above metal elements can be in the form of elemental substances or intermediate alloys. According to the requirements of the strength and other properties of the finished maraging steel, the appropriate element ratio is determined, and the corresponding weight of the raw material is prepared into spherical powder. The particle size of the prepared spherical powder can be 10 μm-200 μm, for example, 10 μm, 15 μm, 50 μm, 53 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, which is convenient for subsequent additive manufacturing process. Gas atomization refers to the process of using high-pressure gas flow as an atomizing medium to break the continuous molten metal stream to prepare metal powder. By selecting a suitable gas atomization technology, the particle size and particle size distribution of the spherical powder can be effectively controlled to obtain powder with particle size in the above range and concentrated distribution.

[0047] Step S20, laser additive manufacturing treatment is performed on the spherical powder to obtain a preform;

[0048] The laser additive manufacturing treatment refers to a process of using laser as a heat source to melt the material to be treated for additive manufacturing. The melting point of the metal element is high, and the laser additive manufacturing technology can quickly melt the metal element in solid powder state at high temperature, and form a preform after cooling and solidification. Laser additive manufacturing technology can realize near-net-shape forming of high-performance and complex structure parts, reduce waste of raw materials, and further reduce the preparation cost.

[0049] Step S30, heat treatment is performed on the preform to obtain the maraging steel.

[0050] The heat treatment method in this embodiment can be direct aging heat treatment, which refers to a heat treatment process in which the metal is subjected to solid solution treatment, quenched from high temperature or deformed by cold working to a certain extent, and then placed at a high temperature or room temperature to maintain its shape, size, and performance changes over time. For example, the aging temperature can be set to 480-550°C, for example, 480°C, 500°C, 520°C, 550°C, the holding time is 1-5h, for example, 1h, 2h, 3h, 4h, 5h, and the cooling method is air cooling. The preform obtained by laser additive manufacturing has a certain shape, and the strength of the preform is improved, and finally the finished maraging steel with the desired shape and structure is obtained.

[0051] In this embodiment, the laser additive manufacturing method is used to prepare the maraging steel according to the element ratio of the above maraging steel, to realize the near-net-shape forming of the maraging steel parts, and on the basis of low-cost raw material selection, the finished product with strength meeting the use requirements is prepared, which expands the application range of the maraging steel parts.

[0052] Further, in the second embodiment of the additive manufacturing method of the maraging steel of the present application, the method comprises:

[0053] Step S21, obtaining a three-dimensional model of the maraging steel;

[0054] According to the structure of the maraging steel part, a three-dimensional model thereof can be drawn using mechanical design software, and then the three-dimensional model is read by a powder bed laser fusion device. The three-dimensional model can include structural parameters of the maraging steel, and the process parameters in the actual additive manufacturing process are designed according to the structural parameters.

[0055] Step S22, slicing the three-dimensional model to obtain slice layer parameters of a plurality of slice layers;

[0056] In the powder bed laser fusion process, the metal powder is melted by scanning a high-power laser on the powder bed. The slicing process of the three-dimensional model can be regarded as using a plane to intersect with the three-dimensional model, and the part where the plane and the model coincide is the slice layer. For example, taking the top or bottom of the three-dimensional model as the starting position, selecting a horizontal plane intersecting with the three-dimensional model, moving the horizontal plane at a certain interval each time to obtain a slice layer, until the plane no longer intersects with the three-dimensional model, and all slice layers are obtained. The slice layer has slice layer parameters, which can include slice layer position, slice layer shape, slice layer size, etc.

[0057] Step S23, laying the spherical powder into a powder layer according to the slice layer parameters;

[0058] The spherical powder can be laid on the substrate of the powder bed laser fusion device. Before laying, the substrate is subjected to sandblasting treatment to increase the friction between the powder and the substrate and prevent the powder from dispersing excessively. The position of the substrate can also be adjusted to be parallel to the horizontal plane, the substrate is preheated, and then the spherical powder is laid on the substrate according to the slice layer position, slice layer shape, and slice layer size in the slice layer parameters to form a powder layer. The spherical powder in the powder layer can be subjected to screening treatment. After obtaining spherical powder with a particle size of 10-200 μm, the powder with a particle size of 15-53 μm suitable for powder bed fusion forming is screened out.

[0059] Step S24, powder bed fusion forming the powder layer to obtain the preform.

[0060] After the powder layer is laid, the laser can be turned on to scan the powder layer, melt the powder layer at high temperature, and form a single-layer part after cooling. By repeating the powder laying and laser scanning process, a preform maraging steel part with the expected structure can be formed by layer-by-layer stacking.

[0061] Exemplarily, the laser power in the shaping process can be set to 150W-300W, the scanning speed to 800mm / s-1500mm / s, the scanning interval to 50μm-120μm, and the powder layer thickness to 30μm-110μm. The scanning interval can be regarded as the interval between the paths passed by the laser scanning. In order to avoid oxidation of the molten pool surface in the printing process, Ar gas can be filled into the printing equipment to form a protective atmosphere.

[0062] In the embodiment, the preform of the maraging steel is prepared by the powder bed laser fusion shaping method, the prepared preform has a shape in accordance with the expected design, is suitable for parts with relatively regular structures, and combined with a subsequent heat treatment process, a maraging steel finished product with a strength meeting the use requirements can be obtained.

[0063] Further, in the second embodiment of the additive manufacturing method of the maraging steel of the present application, the method comprises:

[0064] Step S25, obtaining a three-dimensional model of the maraging steel;

[0065] According to the structure of the maraging steel part, a three-dimensional model thereof can be drawn using a mechanical design software, and then the three-dimensional model is read by a direct energy deposition shaping device. The three-dimensional model can include structural parameters of the maraging steel, and the process parameters in the actual additive manufacturing process are designed according to the structural parameters.

[0066] Step S26, planning a scanning path according to the three-dimensional model to obtain a plurality of scanning paths;

[0067] The scanning path refers to the path passed by the laser cladding head in the direct energy deposition shaping process. After a plurality of scanning paths are obtained, the laser cladding head can be controlled to move according to the scanning paths, the spherical powder is fed into the molten pool, the powder is melted and solidified to form a weld bead, and the part is shaped by multiple passes. According to the scanning path, a program code can be written, and the program code is input into the direct energy deposition device to control the laser cladding head to move according to the scanning path.

[0068] Step S27, directly energy deposition shaping the spherical powder according to the scanning path to obtain the preform.

[0069] The forming process can be carried out on the substrate, first sandblasting the substrate, leveling the substrate position, adjusting the laser focal length to the appropriate position on the substrate. The spherical powder is loaded into the powder feeding tank of the direct energy deposition device, the powder feeding disc rotation speed and the flow rate of the powder feeding protective gas are set, the spherical powder is ready to start powder feeding, and the laser cladding head is deposited according to the scanning path. Forming, layer by layer, to form a preform part. The spherical powder loaded into the powder feeding tank can be sieved. After preparing spherical powder with a particle size of 10-200 μm, the powder with a particle size of 53-150 μm suitable for direct energy deposition forming is sieved out.

[0070] For example, the laser power in the forming process can be set to 1.0-2.0 kW, the scanning speed to 500-1000 mm / s, and the single-layer thickness of laser cladding to 0.8-1.2 mm; the powder feeding gas flow rate to 1-2 L / min; the protective gas beam diameter to 5 mm, and the protective gas beam to move with the laser beam as the center, with a flow rate of 1-5 L / min. In order to avoid oxidation of the molten pool surface during printing, Ar gas can be blown into the molten pool as a protective atmosphere during deposition.

[0071] In this embodiment, the preform of maraging steel is prepared by direct energy deposition method, and the laser cladding deposition forming method can take into account high efficiency and high forming precision, and is suitable for forming complex structure parts.

[0072] Example 1

[0073] The powder bed laser fusion forming maraging steel adopts pre-alloyed atomized powder, and the powder composition (wt%) is Fe-19.5Ni-3.5Al-0.15Nb-0.05C-0.15Mn-0.001B. The powder particle size is 15-53 μm.

[0074] Parameter setting: laser power: 200 W; scanning rate: 900 mm / min; scanning interval: 110 μm; powder layer thickness: 30 μm. Combined with the high-speed cooling and solidification conditions of the process, the printing process is equivalent to solid solution, and direct aging treatment is used, with a temperature T of 500°C and a holding time of 120 min. After heat treatment, air cooling is carried out.

[0075] Performance test: Figure 2 The physical map of the maraging steel prepared in Example 1 is shown. The sample is cut for tensile test, Figure 3 The stress-strain curve of the maraging steel prepared in Example 1 is shown, Figure 3The tensile strength of the material after aging is 2060 MPa, the yield strength is 2011 MPa, and the elongation at break is 7.7%, which is better than the corresponding indicators of 18Ni300. Electron microscopy detection shows that the alloy structure is martensitic structure and a small amount of residual, the density is more than 99.5%, and the precipitated phase is mainly NiAl phase with a size of less than 5 nm and NbC phase with a size of less than 10 nm.

[0076] Example 2

[0077] The direct energy deposition forming martensitic age steel adopts pre-alloyed atomized powder, and the powder composition (wt%) is Fe-17Ni-3.5Al-0.1Nb-0.05C-0.17Mn-0.0015B. The powder particle size is 53-150 μm.

[0078] Parameter setting: laser power: 1.4 kW; printing rate: 600 mm / min; powder feeding rate: 12 g / min; protective gas: 25 L / min; laser cladding single layer thickness 1 mm. Direct aging treatment is adopted. Heat treatment temperature T = 550℃, holding time 120 min, and air cooling after heat treatment.

[0079] Performance test: Figure 4 The physical map of the martensitic age steel prepared in Example 2. Figure 5 The electron backscattering diagram of the martensitic age steel prepared in Example 2. The EBSD (Electron Back Scatter Diffraction) analysis of the cut sample shows that under the condition of rapid cooling, the grain is refined and there is no obvious anisotropy. The room temperature strength reaches 1860 MPa, the hardness reaches 550 HV, and the elongation at break is 8.7%.

[0080] The thermal cycle process of direct energy deposition promotes the austenite inversion, resulting in a decrease in hardness and an increase in elongation.

[0081] Example 3

[0082] The powder bed laser fusion forming martensitic age steel adopts pre-alloyed atomized powder, and the powder composition (wt%) is Fe-21.5Ni-3.0lAl-0.15Nb-0.12C-0.10Mn-0.0012B. The powder particle size is 15-53 μm.

[0083] Parameter setting: laser power: 200 W; scanning rate: 900 mm / min; scanning interval: 110 μm; powder layer thickness 30 μm. Combined with the high-speed cooling and solidification conditions of the process, the printing process is equivalent to solid solution, and the present embodiment directly adopts aging treatment, temperature T = 500℃, holding time 120 min, and air cooling after heat treatment.

[0084] Performance test: The sample was cut for tensile test, the stress-strain curve showed that the tensile strength of the material reached 2098 MPa after aging strengthening, and the yield strength was 2175 MPa.

[0085] With the increase of carbon content, the strength and hardness increase, but the elongation decreases.

[0086] Example 4

[0087] The direct energy deposition forming maraging steel adopts pre-alloyed atomized powder, and the powder composition (wt%) is Fe-17.5Ni-6.0Al-0.08Nb-0.08C-0.25Mn-0.0011B. The powder particle size is 53-150 μm.

[0088] Parameter setting: laser power: 1.4 kW; printing rate: 600 mm / min; powder feeding rate: 12 g / min; protective gas: 25 L / min; single layer thickness of laser cladding 1 mm. Direct aging treatment is adopted. Heat treatment temperature T=550℃, holding time 120 min, and air cooling after heat treatment is completed.

[0089] Performance test: the room temperature strength reaches 1960 MPa, the hardness reaches 620 HV, but the elongation at break is 4.7%.

[0090] The increase of Al content promotes the generation of high-density NiAl phase, which is beneficial to the increase of strength and the decrease of material density. However, NiAl is a brittle phase, which leads to the decrease of elongation of the material.

[0091] The above-mentioned example numbers of the application are only for description, and do not represent the advantages and disadvantages of the examples.

[0092] The above is only the preferred embodiment of the application, and does not limit the patent scope of the application, and any equivalent structure or equivalent process transformation according to the content of the specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the application.

Claims

1. A martensitic aging steel, characterized in that, The martensitic aging steel, prepared by additive manufacturing, comprises, by weight percentage: 0.03%-0.15% C, 17.0%-22.0% Ni, 2.0%-6.5% Al, 0.05%-0.25% Nb, and 0.10%-0.30% Mn, with the balance being Fe; The strengthening phases of the martensitic aging steel are synergistically precipitated NiAl and NbC phases; The additive manufacturing method for the martensitic aging steel includes the following steps: Raw materials of each element are taken according to weight percentage, and the raw materials are atomized to prepare spherical powder; The spherical powder is subjected to laser additive manufacturing to obtain a pre-form; The preform is subjected to heat treatment to obtain the martensitic aging steel, wherein the heat treatment is a direct aging heat treatment.

2. The martensitic aging steel as described in claim 1, characterized in that, The martensitic aging steel also includes 0.0008%-0.003% B.

3. An additive manufacturing method for martensitic aging steel, characterized in that, The additive manufacturing method for preparing martensitic aging steel as described in any one of claims 1-2 includes the following steps: Raw materials of each element are taken according to weight percentage, and the raw materials are atomized to prepare spherical powder; The spherical powder is subjected to laser additive manufacturing to obtain a pre-form; The preform is subjected to heat treatment to obtain the martensitic aging steel, wherein the heat treatment is a direct aging heat treatment.

4. The additive manufacturing method for martensitic aging steel as described in claim 3, characterized in that, The particle size of the spherical powder is 10μm-200μm.

5. The additive manufacturing method for martensitic aging steel as described in claim 3, characterized in that, The step of performing laser additive manufacturing on the spherical powder to obtain a pre-product includes: Obtain the three-dimensional model of the martensitic aging steel; The three-dimensional model is sliced ​​to obtain slice layer parameters for multiple slice layers; The spherical powder is laid into a powder layer according to the parameters of each slice layer; The powder layer is subjected to powder bed laser melting to form the pre-product.

6. The additive manufacturing method for martensitic aging steel as described in claim 5, characterized in that, The control parameters for powder bed laser melting and forming include: laser power of 150W-300W, scanning speed of 800mm / s-1500mm / s, scanning spacing of 50μm-120μm, and powder layer thickness of 30μm-110μm.

7. The additive manufacturing method for martensitic aging steel as described in claim 3, characterized in that, The step of performing laser additive manufacturing on the spherical powder to obtain a pre-product includes: Obtain the three-dimensional model of the martensitic aging steel; Based on the 3D model, multiple scanning paths are planned to obtain them. The spherical powder is directly energy-deposited and shaped according to the scanning path to obtain the preform.

8. The additive manufacturing method for martensitic aging steel as described in claim 7, characterized in that, The control parameters for direct energy deposition forming include: laser power of 1.0kW-2.0kW, scanning speed of 500mm / s-1000mm / s, single-layer thickness of laser cladding of 0.8mm-1.2mm, powder feeding gas flow rate of 1L / min-2L / min, protective gas beam diameter of 5mm, the protective gas beam moving with the laser beam as the center, and flow rate of 1L / min-5L / min.

9. The additive manufacturing method for martensitic aging steel according to any one of claims 3-8, characterized in that, The aging temperature of the direct aging heat treatment is 480℃-550℃, the holding time of the direct aging heat treatment is 1h-5h, and the cooling method of the direct aging heat treatment is air cooling.

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