FeMnAlC light-weight high-strength steel based on electron beam 3D printing technology and preparation method of FeMnAlC light-weight high-strength steel

Abstract

The invention relates to the technical field of preparation of light-weight high-strength steel through electron beam selective melting, in particular to FeMnAlC light-weight high-strength steel based on an electron beam 3D printing technology and a preparation method of the FeMnAlC light-weight high-strength steel based on the electron beam 3D printing technology. Designing a three-dimensional digital model; layering a discrete model, obtaining powder parameters and scanning data, and importing the data into electron beam scanning control software; preheating parameters, a printing strategy and printing parameters are set for printing, and the printing parameters are as follows: the scanning speed is 2.5-3 m / s, the current speed is 7-9 mA, and the rotation angle is 90 degrees; and after printing is completed, a formed part is cooled to the room temperature, sand blasting treatment is conducted on the formed part, powder is removed, and the FeMnAlC light-weight high-strength steel obtained through electron beam selective melting is obtained.By means of the method, the problems that in the traditional high-carbon high-alloy steel casting process, the fluidity is poor, the structure is uneven, and a complex shape cannot be designed for a casting to meet the use condition are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing lightweight high-strength steel by electron beam selective melting, and in particular to a FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology and a preparation method thereof. Background Art

[0002] With the development of industry and technology, the requirements for materials are getting higher and higher, especially in the fields of aerospace, automobile manufacturing and high-end equipment manufacturing, there is an urgent need for lightweight and high-strength materials. Electron beam 3D printing technology (EBM) is an advanced additive manufacturing technology. Compared with traditional manufacturing methods, EBM technology has the advantages of high precision, high material utilization, controllable internal structure and short manufacturing cycle. At the same time, electron beam selective melting technology gives high flexibility to material manufacturing, which can realize the direct manufacturing of complex shapes and structures without the need for mold design and manufacturing in the traditional manufacturing process, greatly shortening the product development cycle and reducing costs. It solves the problem of uneven organization in the traditional high-carbon alloy steel casting process and the inability to design complex shapes of castings to meet the use conditions.

[0003] However, it is difficult to control the printing process of complex FeMnAlC structures with existing technologies. High-energy electron beams may cause local temperatures to be too high, resulting in heat-affected zones, affecting the microstructure and properties of the material and leading to low density of the workpiece. The focusing accuracy of the electron beam is limited, which may lead to uneven bonding between layers, affecting the accuracy and consistency of the final product. Summary of the invention

[0004] In view of the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a FeMnAlC lightweight and high-strength steel based on electron beam 3D printing technology and a preparation method thereof. The method of the present invention solves the difficulties in controlling the printing process of complex structures of FeMnAlC in the prior art. The high-energy electron beam may cause excessive local temperature, produce a heat-affected zone, affect the microstructure and properties of the material, and lead to a low density of the workpiece; the focusing accuracy of the electron beam is limited, which may lead to uneven bonding between layers, affecting the accuracy and consistency of the final product.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A method for preparing FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology, comprising the following steps:

[0007] FeMnAlC powder is prepared according to the mass percentage of C: 1.3-1.7%, Al: 7-12%, Cr: 1.5-3%, Mn: 20-30%, Zn: 1.5-1.7%, and the balance is Fe, which is 100% in total;

[0008] Load FeMnAlC powder into the powder bin of the 3D printing equipment and design a three-dimensional digital model;

[0009] Layering discretized three-dimensional digital model, obtaining powder parameters and scanning data, and importing the powder parameters and scanning data into electron beam scanning control software;

[0010] Set the preheating parameters, and set the printing parameters according to the printing path for printing, where the scanning speed is 2.5m / s to 3.5m / s, the current speed is 7mA to 9mA, and the rotation angle is 90°;

[0011] After printing is completed, the formed part is cooled to room temperature, and the formed part is sandblasted to remove the powder to obtain electron beam selectively melted FeMnAlC lightweight and high-strength steel.

[0012] The present invention ensures that the ratio of Fe, Mn, Al, C and other elements can meet the performance requirements of light weight and high strength by selecting and proportioning the alloying elements in FeMnAlC steel, and at the same time takes into account the melting and solidification behavior in the 3D printing process, optimizes the microstructure of the material, improves its strength and toughness, and reduces the material density under the premise of ensuring the strength and toughness of the material, so as to achieve the purpose of lightweight. The optimal 3D printing process parameters are determined by experiments to be a scanning speed of 2.5m / s to 3m / s, a current speed of 7mA to 9mA, and a rotation angle of 90°, so as to achieve good molten pool control, molten pool shape and the combination between the molten pool and the layer, so as to ensure that the printed FeMnAlC lightweight and high-strength steel has a uniform microstructure and the required performance.

[0013] In a preferred embodiment of the present invention, the printing parameters are as follows: the substrate temperature is 850° C. to 950° C., and the voltage is 60 kV.

[0014] In a preferred embodiment of the present invention, the layers are discretized into equal-thickness slices, and the slice thickness is 0.1 mm to 0.2 mm.

[0015] In a preferred embodiment of the present invention, the powder parameters include powder element composition, particle size and powder fluidity.

[0016] In a preferred embodiment of the present invention, the scanning data includes slice thickness and scanning path.

[0017] In a preferred embodiment of the present invention, the printing path is a unidirectional scan.

[0018] In a preferred embodiment of the present invention, the FeMnAlC powder has a particle size of 40 μm to 100 μm.

[0019] In a preferred embodiment of the present invention, the three-dimensional digital model is a rectangular three-dimensional digital model with a size of 30 mm×15 mm×10 mm.

[0020] Another object of the present invention is to provide a FeMnAlC lightweight high-strength steel produced based on 3D printing technology as described in any of the above items, wherein the FeMnAlC lightweight high-strength steel consists of two phases, austenite and cementite.

[0021] Electron beam selective melting technology uses a high-energy electron beam as a heat source to scan and melt the metal powder placed on the printing platform. By controlling the scanning path and energy of the electron beam, the shape and size of the melting area can be precisely controlled, thereby building a three-dimensional metal part layer by layer.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention ensures that the ratio of elements such as Fe, Mn, Al, and C can meet the performance requirements of light weight and high strength by selecting and proportioning alloy elements in FeMnAlC steel. At the same time, the melting and solidification behaviors in the 3D printing process are taken into consideration to optimize the microstructure of the material, improve its strength and toughness, and reduce the material density while ensuring the strength and toughness of the material, thereby achieving the purpose of lightweight. Through experiments, it was determined that the optimal 3D printing process parameters are a scanning speed of 2.5m / s to 3m / s, a current speed of 7mA to 9mA, and a rotation angle of 90°, so as to achieve good molten pool control, molten pool shape and the combination of the molten pool and the layer, so as to ensure that the printed FeMnAlC lightweight and high-strength steel has a uniform microstructure and the required performance. Through precise printing parameter control, fine adjustment of the material microstructure can be achieved. For example, the content of different elements will change the phase composition of the alloy, and the element ratio will affect the crystal structure. Higher printing temperature can promote atomic diffusion, high electron beam current energy input, increased melting depth, can change the cooling rate during solidification, affect the formation of microstructure, and make the grains grow. Therefore, through the composition design and adjustment of processing parameters of the present invention, the change of phase composition is achieved, and at the same time, the effect of refining the grains is played, thereby optimizing the mechanical properties of the material.

[0024] 2. The present invention can significantly improve the strength, toughness and other properties of the material through specific alloy design and electron beam selective melting process to meet the needs of specific application fields. The preparation of FeMnAlC steel makes the material have a lower density, which can achieve a lighter structural design compared to traditional materials, which is of great significance to aerospace, automobile manufacturing, mechanical engineering, electronic 3C and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a powder particle size distribution diagram of the present invention;

[0026] Figure 2 Macroscopic images of FeMnAlC lightweight high-strength steel formed parts prepared in Examples 1-3 and Comparative Examples 1-9 of the present invention;

[0027] Figure 3 The microstructure morphology of the FeMnAlC lightweight high-strength steel prepared in Example 1 of the present invention;

[0028] Figure 4 The microstructure morphology of the FeMnAlC lightweight high-strength steel prepared in Example 2 of the present invention;

[0029] Figure 5 The microstructure morphology of the FeMnAlC lightweight high-strength steel prepared in Example 3 of the present invention;

[0030] Figure 6 The microstructure morphology of the FeMnAlC lightweight and high-strength steel prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The following is a detailed description of the technical solutions in the embodiments of the present invention in combination with the preferred embodiments and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that all professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0033] Example 1

[0034] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0035] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0036] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.1 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0037] (3) Setting the printer to print: setting preheating parameters, the preheating temperature is 900° C.; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: substrate temperature is 900° C., scanning speed: 3 m / s, current flow rate: 7 mA, rotation angle: 90°, voltage: 60 kV;

[0038] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0039] (5) Post-printing processing: After printing, the molded part is cooled on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC lightweight high-strength steel.

[0040] Example 2

[0041] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0042] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0043] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.1 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0044] (3) Setting the printer to print: setting preheating parameters, the preheating temperature is 900° C.; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: substrate temperature is 900° C., scanning speed: 2.5 m / s, current flow rate: 9 mA, rotation angle: 90°, voltage: 60 kV;

[0045] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0046] (5) Post-printing processing: After printing, the molded part is cooled on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC lightweight high-strength steel.

[0047] Example 3

[0048] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0049] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0050] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.2 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0051] (3) Setting the printer to print: setting preheating parameters, the preheating temperature is 900° C.; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: substrate temperature is 900° C., scanning speed: 3 m / s, current flow rate: 8 mA, rotation angle: 90°, voltage: 60 kV;

[0052] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0053] (5) Post-printing processing: After printing, the molded part is cooled on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC lightweight high-strength steel.

[0054] Example 4

[0055] The preparation method is the same as that of Example 1, except that the composition mass percentage of the FeMnAlC alloy is replaced by C: 1.3%, Al: 12%, Cr: 1.5%, Mn: 20%, Zn: 1.7%, and the balance is Fe.

[0056] Example 5

[0057] The preparation method is the same as that of Example 1, except that the composition mass percentage of the FeMnAlC alloy is replaced by C: 1.7%, Al: 7%, Cr: 3%, Mn: 30%, Zn: 1.5%, and the balance is Fe.

[0058] Comparative Example 1

[0059] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0060] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0061] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.2 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0062] (3) Setting the printer to print: setting preheating parameters, the preheating temperature is 900° C.; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: substrate temperature is 900° C., scanning speed: 3.5 m / s, current flow rate: 8 mA, rotation angle: 90°, voltage: 60 kV;

[0063] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0064] (5) Post-printing processing: After printing, the molded part is cooled on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC lightweight high-strength steel.

[0065] Comparative Example 2

[0066] A method for preparing FeMnAlC steel by electron beam selective melting comprises the following steps:

[0067] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0068] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.1 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0069] (3) Setting the printer to print: setting preheating parameters, the preheating temperature is 900° C.; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: scanning speed: 3.5 m / s, current flow rate: 9 mA, rotation angle: 90°, voltage: 60 kV;

[0070] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0071] (5) Post-printing processing: After printing, the molded part is allowed to cool on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC steel.

[0072] Comparative Example 3

[0073] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0074] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0075] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.1 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0076] (3) Setting the printer to print: setting the preheating parameters, the preheating temperature is 900°C; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: scanning speed: 4m / s, current flow rate: 9mA, rotation angle: 90°, voltage: 60kV;

[0077] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0078] (5) Post-printing processing: After printing, the molded part is allowed to cool on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC steel.

[0079] Comparative Example 4

[0080] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0081] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0082] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.2 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0083] (3) Setting the printer to print: setting the preheating parameters, the preheating temperature is 900°C; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: scanning speed: 3.5 m / s, current flow rate: 7 mA, rotation angle: 90°, voltage: 60 kV;

[0084] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0085] (5) Post-printing processing: After printing, the molded part is allowed to cool on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC steel.

[0086] Comparative Example 5

[0087] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0088] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0089] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.2 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0090] (3) Setting the printer to print: setting preheating parameters, the preheating temperature is 900°C; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: scanning speed: 3.5 m / s, current flow rate: 10 mA, rotation angle: 90°, voltage: 60 kV;

[0091] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0092] (5) Post-printing processing: After printing, the molded part is allowed to cool on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC steel.

[0093] Comparative Example 6

[0094] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0095] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0096] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.1 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0097] (3) Setting the printer to print: setting preheating parameters, the preheating temperature is 900°C; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: scanning speed: 4.5 m / s, current flow rate: 13 mA, rotation angle: 90°, voltage: 60 kV;

[0098] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0099] (5) Post-printing processing: After printing, the molded part is allowed to cool on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC steel.

[0100] Comparative Example 7

[0101] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0102] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0103] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.1 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0104] (3) Setting the printer to print: setting preheating parameters, the preheating temperature is 900°C; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: scanning speed: 3m / s, current flow rate: 9mA, rotation angle: 90°, voltage: 60kV;

[0105] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0106] (5) Post-printing processing: After printing, the molded part is allowed to cool on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC steel.

[0107] Comparative Example 8

[0108] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0109] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0110] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.2 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0111] (3) Setting the printer to print: setting preheating parameters, the preheating temperature is 900°C; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: scanning speed: 4m / s, current flow rate: 8mA, rotation angle: 90°, voltage: 60kV;

[0112] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0113] (5) Post-printing processing: After printing, the molded part is allowed to cool on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC steel.

[0114] Comparative Example 9

[0115] A method for preparing FeMnAlC lightweight high-strength steel by electron beam selective melting, comprising the following steps:

[0116] (1) Raw material preparation: Select FeMnAlC powder that meets the requirements and perform drying treatment to remove moisture from the powder to ensure the quality of the powder and printing effect, and fill it into the powder bin. Calculated by mass percentage, the composition of the FeMnAlC alloy is C: 1.64%, Al: 7.40%, Cr: 2.82%, Mn: 16.53%, Zn: 1.70%, and the balance is Fe;

[0117] (2) Loading the model: The three-dimensional digital model of a cuboid with a size of 30×15×10 mm is discretized into slices of equal thickness of 0.2 mm to obtain the powder element composition, particle size, powder fluidity, slice corresponding scanning data, slice thickness and scanning path, and import them into the electron beam scanning control software;

[0118] (3) Setting the printer to print: setting the preheating parameters, the preheating temperature is 900°C; setting the printing path to unidirectional scanning according to the printing strategy, setting the printing parameters according to the printing path, the printing parameters are: scanning speed: 5m / s, current flow rate: 15mA, rotation angle: 90°, voltage: 60kV;

[0119] (4) According to the printing parameters of step (3), the powder laying process, preheating process and selective melting process are repeated in sequence, and the printing is stacked layer by layer to complete the printing of the part to be formed;

[0120] (5) Post-printing processing: After printing, the molded part is allowed to cool on the printing bed to room temperature. The cooled molded part is carefully removed from the printing bed using a spatula or other tool, and the removed molded part is sandblasted to remove the powder attached to the surface to obtain FeMnAlC steel.

[0121] Results Analysis

[0122] Set the printing parameters shown in Table 1 below according to the printing path;

[0123] Table 1 Printing parameters of Examples 1 to 3 and Comparative Examples 1 to 9

[0124]

[0125]

[0126] Table 1 shows the printing parameters of Examples 1 to 3 and Comparative Examples 1 to 9 of the present invention. Figure 1 The particle size of the FeMnAlC powder used in the present invention can be seen to be 40 to 100 μm; Figure 2 The molded samples are prepared from Examples 1-3 and Comparative Examples 1-9, wherein numbers 1-12 represent Example 1, Example 2, Comparative Example 2, Comparative Example 3, Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6, Comparative Example 7, Comparative Example 1, Comparative Example 8 and Comparative Example 9, respectively. It can be seen that the samples prepared from Examples 1-3 have better molding effects, while the samples prepared from Comparative Examples 1-9 have poor molding effects. The molded parts with better molding effects after post-treatment are observed for microstructure using an optical microscope. Figure 3 to Figure 6 The microstructure diagram of the FeMnAlC lightweight and high-strength steel prepared in Examples 1 to 3 of the present invention and Comparative Example 1 shows that the phases of the products of Examples 1 to 3 are composed of two phases, austenite and cementite, and cementite is found to precipitate on the austenite phase. At the same time, columnar crystals and equiaxed crystals less than 10 μm can be found on the austenite phase. The metallographic structure of the product prepared in Comparative Example 1 is poor, and there are many unfused holes. The results show that the FeMnAlC steel is composed of the original austenite phase or austenite and ferrite. The composition design and adjustment of the processing parameters of the present invention achieve a change in phase composition and at the same time play a role in refining the grains.

[0127] In summary, the present invention ensures that the ratio of elements such as Fe, Mn, Al, and C can meet the performance requirements of light weight and high strength by selecting and proportioning alloy elements in FeMnAlC steel, while taking into account the melting and solidification behavior during 3D printing. The microstructure of the material is optimized, its strength and toughness are improved, and the material density is reduced while ensuring the strength and toughness of the material, thereby achieving the purpose of lightweight. The optimal 3D printing process parameters are determined through experiments to achieve good molten pool control, molten pool shape, and bonding between the molten pool and the layer. This ensures that the printed FeMnAlC lightweight and high-strength steel has a uniform microstructure and the required performance.

[0128] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the attached claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0129] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology, characterized in that: The following steps are involved: FeMnAlC powder is prepared according to the mass percentage of C: 1.3-1.7%, Al: 7-12%, Cr: 1.5-3%, Mn: 20-30%, Zn: 1.5-1.7%, and the balance is Fe, which is 100% in total; Load FeMnAlC powder into the powder bin of the 3D printing equipment and design a three-dimensional digital model; Layering discretized three-dimensional digital model, obtaining powder parameters and scanning data, and importing the powder parameters and scanning data into electron beam scanning control software; Set the preheating parameters, and set the printing parameters according to the printing path for printing, where the scanning speed is 2.5m / s to 3m / s, the current speed is 7mA to 9mA, and the rotation angle is 90°; After printing is completed, the formed part is cooled to room temperature, and the formed part is sandblasted to remove the powder to obtain electron beam selectively melted FeMnAlC lightweight and high-strength steel.

2. The method for preparing FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology according to claim 1, characterized in that: Printing parameters: substrate temperature is 850℃~950℃, voltage is 60kV.

3. The method for preparing FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology according to claim 1, characterized in that: The stratified discretization method is equal-thickness slicing, and the slice thickness is 0.1mm to 0.2mm.

4. The method for preparing FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology according to claim 1, characterized in that: The printing path is unidirectional scanning.

5. The method for preparing FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology according to claim 1, characterized in that: The three-dimensional digital model is a rectangular three-dimensional digital model with a size of 30mm×15mm×10mm.

6. The method for preparing FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology according to claim 1, characterized in that: The powder parameters include powder element composition, particle size and powder fluidity.

7. The method for preparing FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology according to claim 1, characterized in that: The scanning data includes slice thickness and scanning path.

8. The method for preparing FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology according to claim 1, characterized in that: The printing method is: follow the powder laying process, preheating process and selective melting process, repeat them in sequence, and print layer by layer.

9. The method for preparing FeMnAlC lightweight high-strength steel based on electron beam 3D printing technology according to claim 1, characterized in that: The FeMnAlC powder has a particle size of 40 μm to 100 μm.

10. A FeMnAlC lightweight high-strength steel produced by electron beam 3D printing technology according to any one of claims 1 to 9, characterized in that: The FeMnAlC light high-strength steel consists of two phases: austenite and cementite.

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