High-surface-tension metal powder-cored wire based on stacking fault energy optimization design and preparation method and application of high-surface-tension metal powder-cored wire

Abstract

The invention discloses a high surface tension metal powder core welding wire based on stacking fault energy optimization design and a preparation method and application thereof.The welding wire comprises an outer layer steel belt and an inner powder core, the outer layer steel belt is made of alloy steel, and the inner powder core comprises, by mass, 18%-32% of Mn, 0.9%-1.3% of C, 1.5%-2.5% of Si, 0.8%-1.5% of Al, 0.2%-0.6% of Ti, 0.5%-2.7% of Cu, 0.02%-0.08% of B, 0.08%-0.2% of RE and the balance Fe. And the balance of Fe and inevitable impurity elements. By accurately regulating and controlling the components and the structural design of the welding wire, a collaborative improvement stacking fault energy accurate regulation and control system of the stability and the mechanical property of a molten pool in the additive manufacturing process is achieved, the system is used for electric arc additive manufacturing of parts for aerospace, machinery and vehicle energy, and the quality and the performance of high manganese steel additive manufacturing parts are improved.

Description

Technical Field

[0001] The present invention belongs to the field of additive manufacturing materials, and particularly relates to a high surface tension metal cored wire based on stacking fault energy optimization design, its preparation method and application. Background Art

[0002] Due to its excellent mechanical properties, such as high strength, high toughness and good wear resistance, high manganese steel has great application potential in the field of additive manufacturing. However, there are some problems in additive manufacturing of high manganese steel. For example, it is difficult to precisely control the stacking fault energy of traditional high manganese steel materials, resulting in defects such as uneven microstructure and cracks during the manufacturing process. In addition, during the additive manufacturing process of ordinary welding wires, the surface tension of the molten pool is insufficient, making it difficult to guarantee the forming quality and affecting the accuracy and performance of the parts.

[0003] The level of stacking fault energy directly affects the plastic deformation mechanism, crack propagation behavior and final mechanical properties of materials. During the additive manufacturing process, the optimization of stacking fault energy is crucial for controlling the microstructure of materials, reducing crack defects and improving the forming quality. Stacking fault energy is one of the key parameters connecting crystal structure and macroscopic properties, and has a decisive influence on the deformation mechanism, phase transformation behavior and mechanical properties of materials. By regulating the stacking fault energy, the strength and toughness, formability and durability of materials can be optimized.

[0004] At present, there is little research on metal cored wires for additive manufacturing of high manganese steel that can effectively optimize the stacking fault energy and have high surface tension. The existing welding wires cannot well meet the harsh requirements of high manganese steel additive manufacturing for material properties, restricting the wide application of high manganese steel in the field of additive manufacturing. Therefore, it is of great practical significance to develop a metal cored wire with high surface tension and capable of optimizing the stacking fault energy for additive manufacturing of high manganese steel. Summary of the Invention

[0005] The purpose of the present invention is to provide a high surface tension metal cored wire based on stacking fault energy optimization design, to solve the problems in the prior art that it is difficult to precisely control the stacking fault energy during the additive manufacturing of high manganese steel and the surface tension of the molten pool is insufficient, resulting in poor forming quality, and to improve the quality and performance of high manganese steel additive manufacturing parts through material optimization design.

[0006] Another object of the present invention is to provide a preparation method for the above-mentioned high surface tension metal cored wire based on stacking fault energy optimization design, which has a simple process and is suitable for large-scale production.

[0007] Another object of the present invention is to provide the application of the above-mentioned high surface tension metal cored wire based on stacking fault energy optimization design in additive manufacturing of high manganese steel.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] In the first aspect of the present invention, a metal cored wire with high surface tension based on optimized design of stacking fault energy is provided, which includes an outer steel strip and an inner cored powder. The outer steel strip is made of alloy steel, and the components in the alloy steel are by mass percentage: C 0.03 - 0.15%, Si 0.1 - 0.3%, Mn 0.8 - 1.2%, Cr 12 - 15%, Ni 0.5 - 1.5%; the components in the inner cored powder are by mass percentage: Mn 18 - 32%, C 0.9 - 1.3%, Si 1.5 - 2.5%, Al 0.8 - 1.5%, Ti 0.2 - 0.6%, Cu 0.5 - 2.7%, B 0.02 - 0.08%, RE 0.08 - 0.2%, and the balance is Fe and inevitable impurity elements, where RE is composed of one or more selected from La, Y, Ce.

[0010] Preferably, the raw materials of each component include electrolytic manganese with a purity ≥ 99%, graphite powder, ferrosilicon (Si content ≥ 75%), aluminum pellets (Al content ≥ 99%), ferrotitanium (Ti content ≥ 30%), ferroboron (B content ≥ 15%), rare earth alloy, and iron powder with a purity ≥ 99%. The rare earth alloy includes one or more of lanthanum iron alloy, yttrium iron alloy, and cerium iron alloy.

[0011] Preferably, the diameter of the metal cored wire with high surface tension is 1.2 - 2.4 mm.

[0012] Preferably, the thickness of the outer steel strip is 0.3 - 0.5 mm, and the width is 8 - 20 mm to ensure tight and uniform wrapping of the cored powder.

[0013] Preferably, the mass ratio of Al to Si in the metal cored wire with high surface tension is 0.8 - 1.2:1.

[0014] Preferably, the mass percentage content of impurity elements in the metal cored wire with high surface tension satisfies: S ≤ 0.005% and harmful trace elements ≤ 0.001%, and the harmful trace elements include one or more of Pb, Sn, and Sb.

[0015] Preferably, the filling rate of the inner cored powder in the metal cored wire with high surface tension is 15% - 30%, and the loose bulk density is 2.27 - 2.92 g / cm 3 .

[0016] Preferably, the stacking fault energy of the metal cored wire with high surface tension is stabilized at 20 - 35 mJ / m 2 , ensuring that the twinning induced plasticity (TWIP) effect dominates the deformation (elongation rate ≥ 40%), and the surface tension is 1.43 - 1.47 N / m.

[0017] The present invention provides a high surface tension metal cored wire based on the optimized design of stacking fault energy. Through precise regulation of the wire composition and structure design, the synergetic improvement of the molten pool stability and mechanical properties during additive manufacturing is realized. Stacking fault energy precise regulation system: Adopt the quaternary collaborative design of Mn-Si-Al-C to stably control the stacking fault energy in the range of 20 - 35 mJ / m 2 interval to ensure that the TWIP effect dominates the deformation mechanism; adopt the gradient cored structure design, with the outer layer being a nano-Al 2 O 3 (0.1 - 0.3 μm) dispersion distribution layer, and the inner layer being Mn-Si pre-alloyed powder to achieve dynamic surface modification of the molten pool. The design idea is as follows: The addition of C element can ensure the weld strength. Si and Mn can deoxidize the weld and improve the weld strength during the welding process of high manganese steel. The addition of Ni can improve the impact toughness of the weld and reduce the ductile-brittle transition temperature of the weld. The addition of Cr can ensure that the weld metal has high strength and hardness. The addition of Ti can deoxidize and increase the formation of acicular ferrite in the microstructure, improving the impact toughness of the weld metal. The addition of Cu can improve the strength and corrosion resistance of the welded joint. The addition of B can reduce the critical cooling rate, promote acicular ferrite, and improve the hardenability, toughness and crack resistance of the wire. The functions of each component are as follows:

[0018] C: Improves the strength of steel, forms carbides and solid solutions during the transformation process, and can improve the hardness and wear resistance of steel.

[0019] Si: A deoxidizer during the welding process, which can prevent the generation of carbon monoxide pores during welding, and at the same time plays a role in solid solution strengthening of the weld, improving the strength and hardness of the weld metal. The type of silicon is #75 ferrosilicon, and high-silicon ferrosilicon acts as a reducing agent. Ferrosilicon is added as an inoculant for ductile iron, and can prevent the formation of carbides, promote the precipitation and spheroidization of graphite, and improve the properties.

[0020] Mn: Select low-carbon ferromanganese, which acts as a deoxidizer and desulfurizer, reduces the tendency of the weld metal to crack during welding, refines the grains, inhibits the formation of proeutectoid ferrite, promotes the formation of acicular ferrite, and has the effect of increasing the strength of the weld metal. The Mn element combined with an appropriate amount of C element can ensure the performance of the welded joint.

[0021] Cr: Produces solid solution strengthening and strengthens the grain boundaries of austenite, but the content cannot be too high, otherwise it will reduce the formability of the joint.

[0022] Ni: Improves the stability of austenite, refines the original austenite grains, and can promote the formation of acicular ferrite to improve the low-temperature impact toughness and ductile-brittle transition temperature of the joint. When the Ni content is low, elements such as Cr and Mo can be used to meet the mechanical properties of the welded joint and reduce the production cost.

[0023] Ti: During the welding process, Ti has a very strong affinity with O, and the formed titanium oxide has a relatively high melting point, which can serve as the nucleation core of acicular ferrite. The addition of a small amount of Ti element can increase the formation of interlocked acicular ferrite in the microstructure and improve the impact toughness.

[0024] Cu: Improves the strength and corrosion resistance of the welded joint and replaces a part of Fe.

[0025] B: Reduces the critical cooling rate, promotes acicular ferrite, and improves the hardenability, toughness and crack resistance of the welding wire.

[0026] RE: Refines the grain, promotes the formation of acicular ferrite, reduces cracks while increasing the toughness of the weld, and also improves the ability of the weld metal to dehydrogenate and deoxidize, reduces the generation of oxide inclusions. At the same time, the gas products of graphene deoxidation overflow, taking away a part of the heat, reducing the eutectics generated due to too high temperature, thereby reducing the crack incidence rate.

[0027] In the second aspect of the present invention, there is provided a method for preparing the high surface tension metal cored wire based on the stacking fault energy optimization design, comprising the following steps:

[0028] Step 1, raw material preparation: Prepare electrolytic manganese with a purity ≥ 99%, graphite powder, ferrosilicon (Si content ≥ 75 wt%), aluminum pellets (Al content ≥ 99 wt%), ferrotitanium (Ti content ≥ 30 wt%), ferroboron (B content ≥ 15 wt%), rare earth alloy and iron powder with a purity ≥ 99%. Screen the above raw materials and dry them at 120 - 150 °C for 2 - 4 hours;

[0029] Step 2, powder core mixing: Add the dried raw materials into a V-type powder mixer in sequence according to the mass percentage, and mix them at a speed of 30 - 50 r / min for 30 - 60 min;

[0030] Step 3, steel strip pretreatment: Clean the surface of the alloy steel strip to remove oil stains and scale;

[0031] Step 4, powder core filling and wire forming: Uniformly fill the powder core mixed in Step 2 into the pre-treated steel strip groove at a speed of 5 - 8 m / min, curl the steel strip and use resistance welding to firmly weld the interface to form a wire blank;

[0032] Step 5, drawing and reducing diameter: Draw and reduce the diameter of the wire blank through a drawing die, and control the amount of diameter reduction per drawing at 0.1 - 0.3 mm;

[0033] Step 6. Surface coating treatment: Degrease and pickling the drawn and reduced-diameter wire, and electrostatically spray an anti-oxidation coating under the conditions of a voltage of 30 kV and a flow rate of 0.5 mL / min.

[0034] Step 7. Precision winding and packaging: Use a precision winding machine to wind the wire after surface coating treatment in Step 6 at a winding speed of 80 - 120 m / min, and use a vacuum aluminized plastic composite film for inner packaging.

[0035] Preferably, in Step 5, the temperature of the annealing treatment in the drawing and reducing process is 600 - 800 °C, and the heat preservation time is 1 - 2 hours.

[0036] Preferably, in Step 6, the anti-oxidation coating is SiO 2 or Al 2 O 3 , with a thickness of 5 - 10 μm.

[0037] In the third aspect of the present invention, there is provided the application of the high surface tension metal cored wire based on the optimized design of stacking fault energy in arc additive manufacturing, including for additive manufacturing of components for aerospace, machinery, and vehicle energy.

[0038] Compared with the prior art, the present invention provides a high surface tension metal cored wire based on the optimized design of stacking fault energy, which has the following beneficial effects:

[0039] 1. Achieve the balance of high precision, high efficiency, and high performance through optimizing the composition design and preparation process, so that the wire can meet the requirements of various additive manufacturing processes.

[0040] 2. Simplify the preparation process and reduce the production cost by optimizing the powder mixing, wire forming, and surface treatment processes. Ensure the uniformity and performance stability of the wire composition by using processes such as ball milling mixing, drawing forming, and annealing treatment, making the wire suitable for large-scale industrial production.

[0041] 3. Effectively prevent the oxidation of the wire during manufacturing and storage, improve the stability of the wire, and at the same time improve the stability of the molten pool, reduce spatter and porosity during the welding process, and improve the mechanical properties and surface quality of the weld by adding stabilizers / anti-oxidants (such as rare earth elements, Al, Si, Mg, Ti, etc.). In addition, the added rare earth elements also act as grain refiners, reducing spatter and inclusions, refining grains, and improving the strength and toughness of the material, and the comprehensive performance of the wire is good.

[0042] 4. Through precise control of the stacking fault energy, the stacking fault energy is stabilized at 20 - 35 mJ / m 2, ensure that the TWIP effect dominates the deformation (elongation rate ≥ 40%), stably control the surface tension at 1.43 - 1.47 N / m, so that the additively manufactured high manganese steel components have higher surface quality and mechanical properties, and are applicable to fields such as additive manufacturing (such as 3D printing) and welding repair.

[0043] V. By strictly controlling the impurity content (such as O ≤ 0.01%, S ≤ 0.005%, P ≤ 0.005%), ensure the purity of the material, reduce the formation of inclusions. The low impurity content significantly improves the toughness, crack resistance and fatigue strength of the material, making the additively manufactured high manganese steel components show higher reliability under harsh working conditions.

[0044] VI. By adding surface active elements (such as Si, Al, etc.), significantly increase the surface tension of the molten metal, so that the molten pool has better fluidity and forming stability during the additive manufacturing process. The high surface tension reduces the spatter and oxide inclusions in the molten pool, improves the surface finish of the formed surface and the interlayer bonding strength, making the components have higher mechanical properties and longer service life.

[0045] VII. By precisely regulating the content of alloying elements (such as Mn, Cr, Ni, etc.) and surface active elements (such as Si, Al, etc.), optimize the stacking fault energy, so that the material is more inclined to deform through the dislocation slip mechanism during the plastic deformation process, thereby reducing the generation of cracks and pores. The optimized stacking fault energy significantly improves the work hardening ability and toughness of the material, making the additively manufactured high manganese steel components show higher crack resistance and durability under complex working conditions. Detailed implementation manners

[0046] In order to more fully understand and demonstrate the technical solutions, objectives and advantages of the present invention, the technical effects produced by the present invention will be further described in detail and completely below in combination with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. It should be noted that for those of ordinary skill in the art, other embodiments obtained without departing from the concept of the present invention all belong to the protection scope of the present invention.

[0047] Unless otherwise specified in the following embodiments, the reagents and materials used are all commercially available.

[0048] The following embodiments propose a preparation method of a high surface tension metal cored wire based on the optimized design of stacking fault energy, and the steps are as follows:

[0049] Step 1, Raw material preparation: Prepare electrolytic manganese with a purity ≥ 99%, graphite powder, ferrosilicon (Si content ≥ 75 wt%), aluminum pellets (Al content ≥ 99 wt%), ferrotitanium (Ti content ≥ 30 wt%), ferroboron (B content ≥ 15 wt%), rare earth alloy, and iron powder with a purity ≥ 99%. Screen the above raw materials and dry them at 120 - 150 °C for 2 - 4 hours;

[0050] Step 2, Powder core mixing: Add the dried raw materials into a V-type powder mixer in sequence according to the mass percentage, and mix them at a rotation speed of 30 - 50 r / min for 30 - 60 min;

[0051] Step 3, Steel strip pretreatment: Clean the surface of the alloy steel strip to remove oil stains and scale;

[0052] Step 4, Powder core filling and wire forming: Fill the powder core mixed in Step 2 into the pre-treated steel strip groove evenly at a speed of 5 - 8 m / min, curl the steel strip, and use resistance welding to firmly weld the interface to form a wire blank;

[0053] Step 5, Drawing and reducing diameter: Draw and reduce the diameter of the wire blank through a drawing die, and control the amount of diameter reduction per drawing at 0.1 - 0.3 mm;

[0054] Step 6, Surface coating treatment: Degrease and pickle the drawn and diameter-reduced wire, and perform electrostatic spraying of an anti-oxidation coating under the conditions of a voltage of 30 kV and a flow rate of 0.5 mL / min;

[0055] Step 7, Precision winding and packaging: Wind the wire after surface coating treatment in Step 6 with a precision winding machine at a winding speed of 80 - 120 m / min, and perform inner packaging with a vacuum aluminized plastic composite film.

[0056] In the above preparation method, in Step (1), ensure that the purity of all raw materials meets the requirements (such as electrolytic manganese ≥ 99%, iron powder ≥ 99%, etc.) to avoid impurities affecting the performance of the wire; control the drying temperature at 120 - 150 °C for 2 - 4 hours to avoid oxidation or deterioration of the raw materials due to excessive temperature; the dried raw materials should be sealed to prevent moisture absorption. Use a suitable sieve to screen the raw materials to remove too large or too small particles and ensure uniform particle size of the raw materials.

[0057] In the above preparation method, in Step (2), control the rotation speed at 30 - 50 r / min to avoid overheating or caking of the powder due to too high a rotation speed; control the powder mixing time at 40 - 60 min to ensure uniform mixing of each component.

[0058] In the above preparation method, in step (3), a suitable cleaning agent (such as an organic solvent or an alkaline cleaning agent) is used to thoroughly remove the oil stains and scale on the surface of the steel strip. After cleaning, the steel strip is thoroughly dried to avoid residual moisture affecting the subsequent process; the thickness of the steel strip after cold rolling is controlled at 0.3 - 0.5 mm to ensure uniform thickness, and scratches or cracks on the surface of the steel strip are avoided during the cold rolling process.

[0059] In the above preparation method, in step (4), ensure that the edges of the steel strip are aligned during coiling to avoid misalignment; control the welding current and time during resistance welding to ensure a firm joint and no obvious welding slag.

[0060] In the above preparation method, in step (5), the reduction in diameter per drawing is controlled at 0.1 - 0.3 mm to avoid wire breakage or surface damage caused by excessive reduction in diameter; a suitable lubricant is used during the drawing process to reduce friction and ensure surface finish.

[0061] In the above preparation method, in step (6), the drying temperature is controlled at 80 - 100 °C for 1 - 2 hours to ensure complete removal of the moisture in the coating. After drying, the wire should be cooled to room temperature before packaging or use.

[0062] Example 1

[0063] This example provides a high surface tension metal cored wire optimized by stacking fault energy design. The mass percentages of its components are: Mn 19.33%, C 1.00%, Cr 1.8%, Si 0.8%, Al 0.5%, Ti 0.1%, Cu 0.5%, B 0.003%, RE 0.05%, and the balance is Fe and unavoidable impurities. The wire is drawn to Φ1.2 mm by the conventional preparation method, and the filling rate of the flux core is 22%. Among them, RE is a complex of La, Ce, and Y, and the element content satisfies 1.5 ≤ Ce / Y ≤ 3.0.

[0064] Example 2

[0065] This example provides a high surface tension metal cored wire optimized by stacking fault energy design. The mass percentages of its components are: Mn 21.78%, C 0.9%, Cr 1.8%, Si 1.2%, Al 0.8%, Ti 0.15%, Cu 0.5%, B 0.005%, RE 0.08%, and the balance is Fe and unavoidable impurities. The wire is drawn to Φ1.6 mm by the conventional preparation method, and the filling rate of the flux core is 25%. Among them, RE is a complex of La, Ce, and Y, and the element content satisfies 1.5 ≤ Ce / Y ≤ 3.0.

[0066] Example 3

[0067] This embodiment provides a high surface tension metal cored wire optimized based on stacking fault energy. The mass percentages of its components are as follows: Mn 23.32%, C 1.10%, Cr 3.3%, Si 1.00%, Al 0.60%, Ti 0.20%, Cu 0.5%, B 0.004%, RE 0.10%, and the balance is Fe and inevitable impurities. The wire is drawn to Φ2.0mm according to the conventional preparation method, and the filling rate of the flux core is 22%. Among them, RE is a complex of La, Ce, and Y, and the element content satisfies 1.5 ≤ Ce / Y ≤ 3.0.

[0068] Example 4

[0069] This embodiment provides a high surface tension metal cored wire optimized based on stacking fault energy. The mass percentages of its components are as follows: Mn 25.50%, C 1.20%, Cr 3.3%, Si 1.50%, Al 0.70%, Ti 0.18%, Cu 0.6%, B 0.006%, RE 0.12%, and the balance is Fe and inevitable impurities. The wire is drawn to Φ1.4mm according to the conventional preparation method, and the filling rate of the flux core is 20%. Among them, RE is a complex of La, Ce, and Y, and the element content satisfies 1.5 ≤ Ce / Y ≤ 3.0.

[0070] Example 5

[0071] This embodiment provides a high surface tension metal cored wire optimized based on stacking fault energy. The mass percentages of its components are as follows: Mn 26.43%, C 0.80%, Cr 3.3%, Si 0.60%, Al 0.40%, Ti 0.12%, Cu 0.6%, B 0.002%, RE 0.06%, and the balance is Fe and inevitable impurities. The wire is drawn to Φ1.8mm according to the conventional preparation method, and the filling rate of the flux core is 23%. Among them, RE is a complex of La, Ce, and Y, and the element content satisfies 1.5 ≤ Ce / Y ≤ 3.0.

[0072] Example 6

[0073] This embodiment provides a high surface tension metal cored wire optimized based on stacking fault energy. The mass percentages of its components are as follows: Mn 28.3%, C 1.05%, Cr 3.5%, Si 1.10%, Al 0.65%, Ti 0.16%, Cu 0.5%, B 0.0045%, RE 0.09%, and the balance is Fe and inevitable impurities. The wire is drawn to Φ2.2mm according to the conventional preparation method, and the filling rate of the flux core is 23%. Among them, RE is a complex of La, Ce, and Y, and the element content satisfies 1.5 ≤ Ce / Y ≤ 3.0.

[0074] Examples 1-6 all adopted automated laser welding. Comparative Examples 1 and 2 were selected from a certain brand of high manganese steel welding wire on the market. The mechanical properties and forming properties of the products after additive manufacturing of high manganese steel with the above welding wires are shown in Table 1.

[0075] Table 1

[0076]

[0077] As can be seen from Table 1, in Comparative Examples 1 and 2, the stacking fault energy was not regulated. The properties such as yield strength, tensile strength, and elongation of the products after additive manufacturing of high manganese steel with their welding wires were inferior to those of Examples 1-6. The products after additive manufacturing of the high surface tension metal cored welding wires prepared in Examples 1-6 had good yield strength, tensile strength, high elongation, and low spatter rate. Among them, the yield strength was not less than 727 MPa, the tensile strength was not less than 827 MPa, the elongation after fracture was 47.7%-50.9%, the spatter rate was 1.7%-2.2%, the surface tension of the molten pool was 1.43-1.47 N / m, and the stacking fault energy was 31-33 mJ / m 2 , compared with Comparative Examples 1 and 2, the high surface tension metal cored welding wires based on the optimized design of stacking fault energy in Examples 1-6 brought better mechanical properties and forming properties while meeting the requirements of lightweight manufacturing.

[0078] In summary, the high surface tension metal cored welding wire based on the optimized design of stacking fault energy in the present invention forms a high surface tension welding wire by reasonably designing and regulating the chemical composition of the welding wire and introducing surface active elements, changing the influence of traditional low surface tension on the molten pool forming. Its application in additive manufacturing parts, especially suitable for additive manufacturing of parts for aerospace, machinery, and vehicle energy, has excellent comprehensive performance.

[0079] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high surface tension metal powder cored welding wire designed based on stacking fault energy optimization, characterized in that: The invention comprises an outer steel strip and an inner powder core, wherein the outer steel strip is made of alloy steel, wherein the components in the alloy steel are calculated by mass percentage as follows: C 0.03-0.15%, Si 0.1-0.3%, Mn 0.8-1.2%, Cr 12-15%, and Ni 0.5-1.5%; and the components in the inner powder core are calculated by mass percentage as follows: Mn 18-32%, C 0.9-1.3%, Si 1.5-2.5%, Al 0.8-1.5%, Ti 0.2-0.6%, Cu 0.5-2.7%, B 0.02-0.08%, and RE 0.08-0.2%, and the remainder is Fe and unavoidable impurity elements, wherein RE is a composite of one or more selected from La, Y, and Ce.

2. The high surface tension metal powder cored welding wire based on stacking fault energy optimization design according to claim 1, characterized in that: The raw materials of each component include electrolytic manganese with a purity of ≥99%, graphite powder, ferrosilicon with Si≥75wt%, aluminum particles with Al≥99wt%, ferrotitanium with Ti≥30wt%, ferroboron with B≥15wt%, rare earth alloy, and iron powder with a purity of ≥99%, wherein the rare earth alloy includes one or more of lanthanum-iron alloy, yttrium-iron alloy, and cerium-iron alloy.

3. The high surface tension metal powder cored welding wire based on stacking fault energy optimization design according to claim 1, characterized in that: The diameter of the high surface tension metal powder core welding wire is 1.2-2.4 mm; and / or the outer steel strip has a thickness of 0.3-0.5 mm and a width of 8-20 mm; And / or the filling rate of the internal powder core is 15%-30%, and the bulk density is 2.27-2.92g / cm 3 .

4. The high surface tension metal powder cored welding wire based on stacking fault energy optimization design according to claim 1, characterized in that: The mass ratio of Al to Si in the high surface tension metal powder core welding wire is 0.8-1.2:

1.

5. The high surface tension metal powder cored welding wire based on stacking fault energy optimization design according to claim 1, characterized in that: The mass percentage of impurity elements in the high surface tension metal powder cored welding wire satisfies: S≤0.005% and harmful trace elements≤0.001%, and the harmful trace elements include one or more of Pb, Sn, and Sb.

6. The high surface tension metal powder cored welding wire based on stacking fault energy optimization design according to claim 1, characterized in that: The stacking fault energy of the high surface tension metal powder core welding wire is stabilized at 20-35 mJ / m 2 , elongation ≥ 40%, surface tension 1.43-1.47N / m.

7. The method for preparing a high surface tension metal powder cored welding wire based on stacking fault energy optimization design according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1, raw material preparation: prepare electrolytic manganese with a purity of ≥99%, graphite powder, ferrosilicon with Si ≥75wt%, aluminum particles with Al ≥99wt%, ferrotitanium with Ti ≥30wt%, ferroboron with B ≥15wt%, rare earth alloy, and iron powder with a purity of ≥99%, screen the above raw materials, and dry them at 120-150°C for 2-4 hours; Step 2, core powder mixing: add the dried raw materials into a V-type powder mixer in order by mass percentage, and mix at a speed of 30-50r / min for 30-60min; Step 3: Pretreatment of steel strip: Clean the surface of the alloy steel strip to remove oil and oxide scale; Step 4, powder core filling and welding wire forming: the powder core mixed in step 2 is evenly filled into the pre-treated steel strip groove at a speed of 5-8m / min, the steel strip is curled and the interface is welded firmly by resistance welding to form a welding wire blank; Step 5, drawing and reducing: the welding wire blank is drawn and reduced through a drawing die, and the amount of each drawing and reducing is controlled within 0.1-0.3 mm; Step 6, surface coating treatment: degreasing and pickling the wire after drawing and reducing the diameter, and electrostatically spraying an anti-oxidation coating under the conditions of a voltage of 30 kV and a flow rate of 0.5 mL / min; Step 7, precision layer winding and packaging: Use a precision layer winding machine to layer wind the welding wire after the surface coating treatment in step 6 at a winding speed of 80-120m / min, and use a vacuum aluminum-plastic composite film for inner packaging.

8. The method for preparing a high surface tension metal powder cored welding wire based on stacking fault energy optimization design according to claim 7, characterized in that: In step 5, the temperature of the annealing treatment in the drawing and reducing process is 600-800° C., and the holding time is 1-2 hours.

9. The method for preparing a high surface tension metal powder cored welding wire based on stacking fault energy optimization design according to claim 7, characterized in that: In step 6, the anti-oxidation coating is SiO2 or Al2O3, and has a thickness of 5-10 μm.

10. Application of the high surface tension metal powder cored welding wire designed based on stacking fault energy optimization according to any one of claims 1 to 6 in arc additive manufacturing, including additive manufacturing of aerospace, machinery and vehicle energy parts.

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