Additive manufacturing method of a heterogeneous shell

Abstract

The application relates to a heterogeneous shell additive manufacturing method. The heterogeneous shell additive manufacturing method is used for processing a warhead-warbody heterogeneous shell, and comprises the following steps: a forming model of the warhead-warbody heterogeneous shell is established, and the forming model is decomposed into a first model, a second model and a third model along a straight line direction; high-carbon high-strength steel powder is selected according to the first model and laser selective melting is carried out to obtain a warbody; an arc wire forming is carried out on the end of one end of the warbody according to the second model and by selecting medium-carbon high-strength steel wire material to obtain a transition layer; and an arc wire deposition forming is carried out on the end of the end of the transition layer away from the warbody according to the third model and by selecting low-carbon ultra-high-strength steel wire material to obtain a warhead. The mechanical properties of the warhead-warbody heterogeneous shell obtained through the additive manufacturing method can reach the standard of forgings, the cost is reduced, the production time is shortened, and the product quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of additive manufacturing, in particular to an additive manufacturing method of a heterogeneous and heterogeneous shell. BACKGROUND

[0002] The performance of traditional single-material steel shells has approached the engineering limit, and the preparation of multi-layer composite shells by fusing different materials is an effective way to further improve their performance. When forming components of heterogeneous materials by welding, powder metallurgy, and solid-phase sintering, there are many defects such as pores, cracks, and poor fusion at the interface, which become a technical bottleneck restricting the development of composite shells.

[0003] At present, the traditional process route of the heterogeneous shell adopts overall forging, cutting processing, and heat treatment, which has problems such as great processing difficulty, long manufacturing cycle, low material utilization rate, and high manufacturing cost, greatly limiting the research and production of the heterogeneous shell.

[0004] The steel for the shell generally adopts medium-carbon medium-alloy steel or high-carbon high-alloy steel, which experiences rapid heating-quick cooling repeated thermal cycles in additive manufacturing, has large internal stress, and the brittle phase of carbide is easy to gather at the grain boundary, so the cracking risk is high and the process control is difficult, and the performance of the shell is difficult to reach the level of forgings. Therefore, it is urgent to carry out research on the additive manufacturing technology of the heterogeneous and heterogeneous shell of the warhead and the body. SUMMARY

[0005] Therefore, it is necessary to provide an additive manufacturing method of a heterogeneous and heterogeneous shell applied to a warhead or a shell, which can improve the forming performance of the heterogeneous and heterogeneous shell.

[0006] An additive manufacturing method of a heterogeneous and heterogeneous shell is used to process a heterogeneous and heterogeneous shell of a warhead and a body, and the additive manufacturing method of the heterogeneous and heterogeneous shell comprises the following steps:

[0007] A forming model of the heterogeneous and heterogeneous shell of the warhead and the body is established, and the forming model is decomposed into a first model, a second model, and a third model along a straight line direction;

[0008] According to the first model, high-carbon high-strength steel powder is selected to perform laser selective melting forming, so as to obtain a body;

[0009] According to the second model, a high-carbon high-strength steel wire is selected to perform arc melting wire forming at the end of one end of the body, so as to obtain a transition layer;

[0010] According to the third model, a low-carbon ultra-high-strength steel wire is selected to perform arc melting wire deposition forming at the end of the end of the transition layer away from the body, so as to obtain a warhead.

[0011] In one embodiment, the carbon content of the high-carbon high-strength steel powder is 0.25% to 0.35%, and the oxygen content is ≤50ppm.

[0012] In one embodiment, the medium-carbon high-strength steel wire has a carbon content of 0.18% to 0.24%, a diameter of 1.3 mm to 1.6 mm, and an oxygen content of ≤30 ppm.

[0013] In one embodiment, the low-carbon ultra-high-strength steel wire has a carbon content of ≤0.1%, a diameter of 1.3 mm to 1.6 mm, and an oxygen content of ≤20 ppm.

[0014] In one embodiment, when the first model is used and a high-carbon high-strength steel powder is selected for laser selective melting, the laser volumetric energy density is 29.22 J / mm 3 ~ 76.19 J / mm 3 ; and / or

[0015] When the first model is used and a high-carbon high-strength steel powder is selected for laser selective melting, the laser scanning speed is 500 mm / s to 700 mm / s, the laser scanning pitch is 0.09 mm to 0.11 mm, and the layer thickness of a single sintering layer is 50 μm to 80 μm.

[0016] In one embodiment, during the manufacturing of the transition layer, the welding current is 130 A to 155 A, the welding voltage is 30 V to 35 V, and the welding speed is 1 mm / s to 3 mm / s.

[0017] In one embodiment, during the manufacturing of the bullet, the welding current is 200 A to 250 A, the welding voltage is 15 V to 22 V, and the welding speed is 4 mm / s to 6 mm / s.

[0018] In one embodiment, the thickness of the transition layer is 5 mm to 10 mm, and in the thickness direction of the transition layer, the size of the body is ≤600 mm and the size of the bullet is ≤300 mm.

[0019] In one embodiment, after the step of arc wire forming at one end of the body of the medium-carbon high-strength steel wire according to the second model, the method further comprises a step of mechanically processing the surface of at least one of the body, the transition layer, and the bullet according to a pre-designed to obtain the bullet body hetero-hetero shell.

[0020] In one embodiment, the transition layer and the bullet are prepared by the arc wire forming process using a multi-head arc additive manufacturing equipment.

[0021] The additive manufacturing method of the warhead and body heterogeneous shell decomposes the warhead and body heterogeneous shell into three parts, and selects different materials, and respectively forms the three parts by different additive manufacturing processes, so as to overcome the problems of uneven heat or mass distribution, deformation caused by thermal stress, delamination and cracking caused by carbon element burning loss or carbonized grain boundary aggregation, and brittle phase metal compound in the whole additive manufacturing process of the warhead and body heterogeneous shell, improve the forming performance of the warhead and body heterogeneous shell, and make the mechanical properties of the warhead and body heterogeneous shell obtained by the additive manufacturing method reach the standard of forgings, while reducing the cost and shortening the production time, and improving the product quality. BRIEF DESCRIPTION OF DRAWINGS

[0022] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not intended to limit the scope of the present application. Furthermore, the same reference numbers in different drawings identify the same components. In the drawings:

[0023] Figure 1 The flowchart of the additive manufacturing method of the heterogeneous shell in the preferred embodiment of the present application is shown in the figure;

[0024] Figure 2 The structure diagram of the warhead and body heterogeneous shell prepared by the additive manufacturing method of the heterogeneous shell shown in the figure is shown in the figure;

[0025] Figure 3 The combination surface between the body and the transition layer and between the transition layer and the warhead in the warhead and body heterogeneous shell shown in the figure is shown in the figure. Figure 2

[0026] Explanation of reference numerals in the detailed description: 10, warhead and body heterogeneous shell; 11, body; 12, transition layer; 13, warhead. DETAILED DESCRIPTION

[0027] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0028] ​Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0029] In describing a position relationship, unless otherwise defined, when an element is referred to as being "on" another element, it can be directly on the other element or there can be an intermediate element. It can also be understood that when an element is referred to as being "between" two elements, it can be the only one between the two elements, or there can be one or more intermediate elements.

[0030] In the case of using "include", "have", and "contain" described herein, unless an explicit limiting term is used, such as "only", "consisting of", and the like, another component can be added. Unless otherwise mentioned, the singular form of the term can include the plural form, and it cannot be understood as the number of one.

[0031] The manufacturing of conventional heterogeneous shells usually adopts two ways, one is to adopt the traditional process route of integral forging, cutting processing and heat treatment, and the other is to adopt integral additive manufacturing of medium-carbon medium-strength alloy steel or high-elastic high-strength alloy steel. The first traditional process route has problems of great processing difficulty, long manufacturing period, low material utilization rate, high manufacturing cost and the like. The second way of integral additive manufacturing of the same material needs to go through additive manufacturing rapid heating, rapid cooling and repeated thermal cycle, which causes great internal stress of the formed structure, easy aggregation of carbide brittle phase at the grain boundary, high cracking risk and great process control difficulty, so that the mechanical properties of the heterogeneous shell are difficult to reach the level of forgings. Based on this, the applicant proposes an additive manufacturing method of heterogeneous shell which can make the mechanical properties of the heterogeneous shell reach the level of forgings, while reducing the processing cost and shortening the production time.

[0032] Please refer to Figure 1 The additive manufacturing method of the heterogeneous shell in the preferred embodiment of the application is used for processing the warhead body heterogeneous shell 10. The additive manufacturing method of the heterogeneous shell comprises steps S100 to S400.

[0033] Please refer to Figure 2 Step S100, a forming model of the warhead body heterogeneous shell 10 is established, and the forming model is decomposed into a first model, a second model and a third model along the straight line direction.

[0034] The straight line direction is consistent with the direction in which the bullet head 13 points to the bullet body 11. The shaped model is a three-dimensional model established according to the bullet body bullet head heterogeneous shell 10, so as to facilitate subsequent additive manufacturing work.

[0035] In step S200, the bullet body 11 is obtained by laser selective melting forming according to the first model and selecting high-carbon high-strength steel powder. In this way, the forming process of the bullet body 11 is laser selective melting forming process, and the material of the bullet body 11 is high-carbon high-strength steel.

[0036] In step S300, the transition layer 12 is obtained by arc wire deposition forming on the end of one end of the bullet body 11 according to the second model and selecting medium-carbon high-strength steel wire. In this way, the transition layer 12 is directly formed on the end of one end of the bullet body 11 and forms an integral whole with the bullet body 11. The forming process of the transition layer 12 is arc wire deposition forming process, and the material of the transition layer 12 is medium-carbon high-strength steel.

[0037] Specifically, the multi-head arc additive manufacturing equipment is used to perform arc wire deposition forming on the end of one end of the bullet body 11 to obtain the transition layer 12.

[0038] In step S400, the bullet head 13 is obtained by arc wire deposition forming on the end of the transition layer 12 away from the bullet body 11 according to the third model and selecting low-carbon ultra-high-strength steel wire. In this way, the bullet head 13 is directly formed on the end of the transition layer 12 away from the bullet body 11, and the bullet head 13 forms an integral whole with the transition layer 12. The forming process of the bullet head 13 is arc wire deposition forming process, and the material of the bullet head 13 is low-carbon ultra-high-strength steel.

[0039] Specifically, the multi-head arc additive manufacturing equipment is used to perform arc wire deposition forming on the end of the transition layer 12 away from the bullet body 11 to obtain the bullet head 13.

[0040] Of course, in other embodiments, step S300 and step S400 can also use other structures of arc wire forming equipment to manufacture the transition layer 12 and the bullet head 13.

[0041] In this way, by executing steps S100 to S400, the bullet body 11 bullet head 13 heterogeneous shell composed of the bullet body 11, the transition layer 12 and the bullet head 13 can be obtained.

[0042] It is proved by practice that in the bullet body 11 bullet head 13 heterogeneous shell obtained by the above additive manufacturing method, the tensile strength of the bullet body 11 is ≥1600MPa, the yield strength is ≥1200MPa, the reduction of area is ≥35%, and the impact toughness is ≥60KJ / m 2Therefore, the mechanical properties of the bullet body 11 meet the performance of the conventional forgings of the high-carbon high-strength steel; the tensile strength of the bullet head 13 is greater than or equal to 1900 MPa, the yield strength is greater than or equal to 1630 MPa, the elongation after fracture is greater than or equal to 10%, and the impact toughness is greater than or equal to 80 J / cm 2 , which fully meets the mechanical properties of the conventional forgings of the low-carbon ultra-high-strength steel; the mechanical properties of the transition layer 12 are between those of the bullet head 13 and the bullet body 11, so the mechanical properties of the transition layer 12 can also meet the mechanical property standards of the conventional forgings of the medium-carbon high-strength steel; the interface strength coefficient between the bullet body 11 and the transition layer 12 is greater than or equal to 80%, and the interface strength coefficient between the transition layer 12 and the bullet head 13 is greater than or equal to 80%, as shown in FIG. 1, at the bonding surface between the bullet body 11 and the transition layer 12 and at the bonding surface between the bullet head 13 and the transition layer 12, the two materials penetrate each other to be tightly combined, so that the structural stability of the bullet body 11 and the bullet head 13 hetero-heterogeneous shell is very strong. Figure 3

[0043] Therefore, in the embodiments of the present application, the bullet head and bullet body hetero-heterogeneous shell 10 is divided into three parts, and different materials are selected to be respectively formed by different additive manufacturing processes, so as to overcome the problems of uneven distribution of heat or mass, deformation caused by thermal stress, delamination and cracking caused by carbon element burning loss or carbonized grain boundary aggregation, and brittle intermetallic compounds and other problems in the process of additive manufacturing of the bullet head and bullet body hetero-heterogeneous shell, improve the forming performance of the bullet head and bullet body hetero-heterogeneous shell 10, so that the mechanical properties of the bullet head and bullet body hetero-heterogeneous shell 10 obtained by the above additive manufacturing method can fully meet the forging standards, while the cost is reduced and the production time is shortened, and the product quality is improved.

[0044] In some embodiments, the carbon content of the high-carbon high-strength steel powder is 0.25% to 0.35%, and the oxygen content is less than or equal to 50 ppm. Because in the process of laser selective melting forming, after the powder is melted, the oxygen element will combine with the easily oxidizable elements to form oxides, which may generate defects such as gas holes in local. Therefore, the oxygen content of the high-carbon high-strength steel powder is controlled to be less than or equal to 50 ppm, so that the oxygen content in the powder is very low, to reduce the probability of generating defects such as gas holes when performing the above step S200, and further improve the mechanical properties and product density of the bullet body 11.

[0045] Specifically, the high-carbon high-strength steel powder further includes the following components in the following mass percentages: Si: 1.4% to 1.9%, Mn: 0.6% to 0.9%, Ni: 4.6% to 6.0%, Cr: 0.9% to 1.2%, Mo: 0.4% to 0.7%, V: less than or equal to 0.35%, Nb: less than or equal to 0.04%, S and P: less than or equal to 0.01%, and Fe: the balance.

[0046] ​In some embodiments, the carbon content of the medium-carbon high-strength steel wire material is 0.18% to 0.24%, the diameter of the medium-carbon high-strength steel wire material is 1.3 mm to 1.6 mm, and the oxygen content is ≤30 ppm.

[0047] In the electric arc wire deposition forming process, after the wire material is melted, the oxygen element will combine with the easily oxidizable elements to form oxides, and it is possible to generate defects such as gas holes in the local. Therefore, the oxygen content of the medium-carbon high-strength steel wire material is controlled to be less than or equal to 30 ppm, and the oxygen content is lower than that of the high-carbon high-strength steel powder. The probability of generating defects such as gas holes when performing the above step S300 is greatly reduced, and the mechanical properties and product density of the transition layer 12 are further improved. The diameter of the medium-carbon high-strength steel wire material is set to 1.3 mm to 1.6 mm, which is very thin, and the product density of the transition layer 12 can be further improved.

[0048] Specifically, the medium-carbon high-strength steel wire material further includes the following components in mass percentage: Cr: 6.2% to 6.4%, Co: 7.2% to 7.5%, Mo: 3 to 3.5, V: 0.55% to 0.85%, Nb: 0.7% to 1.2%, S, P ≤0.01%, and Fe balance.

[0049] In some embodiments, the carbon content of the low-carbon ultra-high-strength steel wire material is ≤0.1%, the diameter of the low-carbon ultra-high-strength steel wire material is 1.3 mm to 1.6 mm, and the oxygen content is ≤20 ppm.

[0050] The oxygen content of the low-carbon ultra-high-strength steel wire material is controlled to be less than or equal to 20 ppm, and the oxygen content is lower than that of the medium-carbon high-strength steel wire material. The probability of generating defects such as gas holes when performing the above step S400 is greatly reduced, and the mechanical properties and product density of the bullet head 13 are further improved. The diameter of the low-carbon ultra-high-strength steel wire material is set to 1.3 mm to 1.6 mm, which is very thin, and the product density of the transition layer 12 can be further improved.

[0051] Therefore, by using the above three materials to perform steps S200 to S400 respectively, the bullet body 11 and the bullet head 13 of the heterogeneous shell obtained by using the above additive manufacturing method have very high mechanical properties and product density, and the product quality is extremely high.

[0052] Specifically, the low-carbon ultra-high-strength steel wire material further includes the following components in mass percentage: Ni: 18.0% to 19.0%, Mo: 4.9% to 5.1%, Al: 0.05% to 0.10%, Co: 7.8% to 8.2%, Ti: 0.40% to 0.50%, Mn ≤0.02%, Si ≤0.05%, S, P ≤0.005%, and Fe balance.

[0053] In some embodiments, when performing step S200, the laser volume energy density is 29.22 J / mm 3~ 76.19 J / mm 3 For the high-carbon high-strength steel powder with a carbon content of 0.25% to 0.35%, the laser volume energy density is 29.22 J / mm 3 ~ 76.19 J / mm 3 is a more suitable energy density, which can reduce the probability of defects such as pores, cracks, spheroidization, spatter, etc. in the forming process of the projectile body 11, and helps to further improve the mechanical properties of the projectile body 11.

[0054] In some embodiments, when step S200 is performed, the laser scanning speed is 500 mm / s to 700 mm / s, the laser scanning interval is 0.09 mm to 0.11 mm, and the layer thickness of a single sintering layer is 50 μm to 80 μm. Therefore, when laser selective melting is performed, the laser scanning speed is very slow, the layer thickness of a single sintering layer (i.e. a printing layer) is large, and the laser scanning interval is very small.

[0055] When step S200 is performed, a slower laser scanning speed is used to further ensure that the grains of the high-carbon high-strength steel powder can grow vertically during laser scanning melting; further, by increasing the layer thickness of the printing layer, macroscopic defects can be avoided, and the included angle between the grain growth direction and the stacking direction can be reduced to prevent the grains from deflecting too much, extend the length of the fine grain zone, and reduce the number of columnar crystal layers; further, by reducing the scanning interval, the large-angle grain boundary area is reduced. Therefore, by setting a slower scanning speed, increasing the layer thickness of the printing layer, and adjusting the scanning interval, the mechanical properties of the projectile body 11 can be further improved.

[0056] In some embodiments, during the manufacturing of the transition layer 12, the welding current is 130 A to 155 A, the welding voltage is 30 V to 35 V, and the welding speed is 1 mm / s to 3 mm / s. In this way, during the forming of the transition layer 12, the welding current is large, the welding voltage is small, and the welding speed is slow.

[0057] In this way, when step S300 is performed, a smaller welding voltage is selected, so that the width of the electric arc is small, thereby making the weld seam during the electric arc wire deposition forming process smaller; further, a larger welding current is used, which increases the thickness of a single deposition layer to avoid macroscopic defects, and reduces the included angle between the grain growth direction and the stacking direction to prevent the grains from deflecting too much, extend the length of the fine grain zone, and reduce the number of columnar crystal layers; further, a slower welding speed is used to further ensure that the grains of the medium-carbon high-strength steel wire material can grow vertically during the electric arc wire deposition forming process. Therefore, by setting a larger welding current, a smaller welding voltage, and a slower welding speed, the mechanical properties of the transition layer 12 can be further improved.

[0058] In some embodiments, during the manufacturing of the bullet head 13, the welding current is 200A-250A, the welding voltage is 15V-22V, and the welding speed is 4mm / s-6mm / s. In this way, during the manufacturing of the bullet head 13, the welding current is much larger than the welding current selected during the manufacturing of the transition layer 12, the welding voltage is smaller than the welding voltage selected during the manufacturing of the transition layer 12, and the welding speed is slightly faster than the welding speed during the manufacturing of the transition layer 12, but is still very slow.

[0059] In this way, when step S400 is performed, a smaller welding voltage is selected, so that the width of the electric arc is smaller, and thus the welding seam during the electric arc wire deposition forming process is smaller. Further, a larger welding current is used, so that the thickness of a single deposition layer is increased, to avoid macro defects, and to reduce the included angle between the grain growth direction and the stacking direction, to prevent the grain from deflecting too much, to extend the length of the fine grain region, and to reduce the number of columnar crystal layers. Further, a slower welding speed is used, to further ensure that the grains of the medium-carbon high-strength steel wire material can grow vertically during the electric arc wire deposition forming process. Therefore, by setting a larger welding current, a smaller welding voltage, and a slower welding speed, the mechanical properties of the bullet head 13 can be further improved.

[0060] Further, the selection of a larger welding current and a smaller welding voltage can further improve the bonding force between the transition layer 12 and the bullet body 11, and the bonding force between the bullet head 13 and the transition layer 12, which is beneficial to improving the overall structural performance of the bullet body 11 and the bullet head 13 of the heterogeneous shell.

[0061] In some embodiments, the thickness of the transition layer 12 is 5mm-10mm. In the thickness direction of the transition layer 12, the size of the bullet body 11 is ≤600mm, and the size of the bullet head 13 is ≤300mm.

[0062] When the bullet body 11 of the bullet body 11 and bullet head 13 heterogeneous shell is placed on a horizontal plane, the thickness direction of the transition layer 12 is the vertical direction, which is also the height direction of the bullet body 11 and bullet head 13 heterogeneous shell. The height of the bullet body 11 is greater than the height of the bullet head 13, and the height of the transition layer 12 is much smaller than the height of the bullet head 13.

[0063] In some embodiments, after step S400, the method further includes a step of: mechanically processing at least one surface of the bullet body 11, the transition layer 12, and the bullet head 13 according to a pre-design, to obtain the bullet body 11 and bullet head 13 heterogeneous shell.

[0064] In this way, any surface of the bullet body 11, the transition layer 12, and the bullet head 13 obtained through steps S100-S400 that does not meet the design requirements is mechanically processed, so that the shape and size of the bullet body 11 and bullet head 13 heterogeneous shell can meet the requirements of the design drawings, to further improve the product quality.

[0065] The technical features of the above-described embodiments can be combined in any manner. For the sake of brevity, not all possible combinations of the technical features are described, but it is understood that the scope of the present specification includes all possible combinations.

[0066] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that, for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An additive manufacturing method for a heterogeneous shell, characterized in that, An additive manufacturing method for processing heterogeneous shells for projectile bodies includes the following steps: A molding model of a heterogeneous shell for a warhead and its body is established, and the molding model is decomposed into a first model, a second model, and a third model along a straight line. Based on the first model, high-carbon high-strength steel powder is selected for laser selective melting to form the projectile body; According to the second model, medium carbon high strength steel wire is selected and arc-fused wire is formed at one end of the projectile body to obtain a transition layer. According to the third model, low-carbon ultra-high strength steel wire is selected and arc-fused wire is deposited at the end of the transition layer away from the projectile body to obtain the projectile. The high-carbon high-strength steel powder has a carbon content of 0.25% to 0.35% and an oxygen content of ≤50ppm; the medium-carbon high-strength steel wire has a carbon content of 0.18% to 0.24% and an oxygen content of ≤30ppm; and the low-carbon ultra-high-strength steel wire has a carbon content of ≤0.1% and an oxygen content of ≤20ppm. When using the first model and selecting high-carbon, high-strength steel powder for laser selective melting and forming, the laser volumetric energy density is 29.22 J / mm². 3 ~76.19J / mm 3 ; When using the first model and selecting high-carbon high-strength steel powder for laser selective melting and forming, the laser scanning speed is 500 mm / s to 700 mm / s, the laser scanning spacing is 0.09 mm to 0.11 mm, and the thickness of a single sintered layer is 50 μm to 80 μm. During the manufacturing process of the transition layer, the welding current is 130 A to 155 A, the welding voltage is 30 V to 35 V, and the welding speed is 1 mm / s to 3 mm / s. During the manufacturing process of the warhead, the welding current is 200A to 250A, the welding voltage is 15V to 22V, and the welding speed is 4mm / s to 6mm / s.

2. The additive manufacturing method according to claim 1, characterized in that, The thickness of the transition layer is 5mm to 10mm; in the thickness direction of the transition layer, the size of the projectile body is ≤600mm and the size of the projectile head is ≤300mm.

3. The additive manufacturing method according to claim 1, characterized in that, After the step of forming the projectile body by arc welding using medium carbon high strength steel wire according to the second model, the method further includes the step of machining the surface of at least one of the projectile body, the transition layer and the projectile head according to a pre-designed method to obtain the heterogeneous shell of the projectile head and projectile body.

4. The additive manufacturing method according to claim 1, characterized in that, The transition layer and the warhead are prepared using multi-head parallel arc additive manufacturing equipment through the electric arc wire forming process.

5. The additive manufacturing method according to claim 1, characterized in that, The diameter of the medium carbon high-strength steel wire is 1.3mm to 1.6mm, and the diameter of the low carbon ultra-high-strength steel wire is 1.3mm to 1.6mm.

6. The additive manufacturing method according to claim 1, characterized in that, The high-carbon, high-strength steel powder also includes the following components by mass percentage: Si: 1.4–1.9%, Mn: 0.6–0.9%, Ni: 4.6–6.0%, Cr: 0.9–1.2%, Mo: 0.4–0.7%, V≤0.35%, Nb≤0.04%, S, P≤0.01%, Fe balance.

7. The additive manufacturing method according to claim 1, characterized in that, The medium-carbon high-strength steel wire also includes the following components by mass percentage: Cr: 6.2-6.4%, Co: 7.2-7.5%, Mo: 3-3.5%, V: 0.55-0.85%, Nb: 0.7-1.2%, S, P≤0.01%, Fe balance.

8. The additive manufacturing method according to claim 1, characterized in that, The low-carbon ultra-high-strength steel wire also includes the following components by mass percentage: Ni: 18.0-19.0%, Mo: 4.9-5.1%, Al: 0.05-0.10%, Co: 7.8-8.2%, Ti: 0.40-0.50%, Mn≤0.02%, Si≤0.05%, S, P≤0.005%, Fe balance.

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