High-manganese low-nickel duplex stainless steel powder core wire as well as preparation method and use method of high-manganese low-nickel duplex stainless steel powder core wire

Abstract

The invention discloses a high-manganese low-nickel duplex stainless steel powder core wire and a preparation and use method thereof, a metal powder core wire is prepared by taking composite powder as a filling core through a rolling and drawing method, and a high-manganese low-nickel duplex stainless steel thin-wall component is obtained by adopting an electric arc additive manufacturing technology according to a target additive path and layer number. The novel high-manganese low-nickel duplex stainless steel powder core wire is composed of a 430 stainless steel strip and a metal powder core. The metal powder core is prepared from, by mass, 30%-40% of metal chromium, 5%-15% of chromium nitride, 25%-40% of electrolytic manganese, 0-5.0% of nickel powder, 1.0%-5.0% of silicon iron, 0.5%-5.0% of ferromolybdenum, 0.5%-3.0% of sodium fluoride, 0.1%-1.5% of cerium oxide and the balance iron powder. The high-manganese low-nickel duplex stainless steel wire is suitable for the additive manufacturing process of welding and various melting wires.

Description

Technical Field

[0001] The invention belongs to the field of welding and additive manufacturing, and specifically relates to a high-manganese and low-nickel duplex stainless steel powder core wire and a preparation and use method thereof. Background Art

[0002] The microstructure of duplex stainless steel is composed of austenite and ferrite in a balanced ratio. It combines the characteristics of austenitic stainless steel and ferritic stainless steel, has excellent mechanical properties and corrosion resistance, and is widely used in industries such as petrochemicals, shipbuilding and construction. Traditional duplex stainless steel uses chromium, nickel and molybdenum as the main alloying elements, but in recent years, the high price of nickel and its continued increase due to the influence of the world situation have seriously hindered the development of the duplex stainless steel industry. For the stainless steel industry, the sharp fluctuations in the prices of scarce raw materials, mainly nickel, are potential risks. Seeking alternatives to high-nickel stainless steel is an emerging field for the development of the stainless steel industry. Therefore, in order to reduce the cost of duplex stainless steel, it is also an important direction for the development of duplex stainless steel to partially or even completely replace nickel with austenitizing elements such as manganese and nitrogen.

[0003] Wire arc additive manufacturing technology uses electric arc as a heat source to melt metal wires and stack them layer by layer to form components. It has the advantages of high forming efficiency, short production cycle, and low cost. Duplex stainless steel has become one of the wires widely used in additive manufacturing due to its good processing performance, forming performance, mechanical properties, and corrosion resistance. The wire used in arc additive manufacturing directly affects the forming quality, chemical composition, organization, and performance of the target component. Therefore, in the field of duplex stainless steel arc additive manufacturing, the design and forming of wires is one of the important directions for future technological development.

[0004] The patent with publication number CN116652449A discloses a flux-cored welding wire for additive manufacturing of offshore pipe structures and its preparation and use methods. The steel strip is 304L stainless steel, and the metal powder core is composed of the following by mass percentage: chromium powder 17.2% to 19%, molybdenum powder 11.8% to 12.2%, manganese powder 4.2% to 4.6%, silicon powder 2.26% to 2.46%, sodium fluoride 0.8% to 1.2%, lanthanum oxide 0.1% to 0.2%, and the rest is iron powder. This is used as a filling material for additive manufacturing of duplex stainless steel offshore pipe structures. The patent with publication number CN102046325B discloses a flux-cored wire for welding duplex stainless steel for refining solidified grains, the chemical composition of which is: C: 0.001-0.1%, Si: 0.01-1.0%, Mn: 2.0-6.0%, Cr: 17.0-27.0%, Ni: 1.0-10.0%, Mo: 0.1-3.0%, A1: 0.002-0.05%, Mg: 0.0005-0.01%, Ti: 0.001-0.5%, N: 0.10-0.30%, and the balance is iron. The weld structure is refined by TiN, and when it is used for welding economical duplex stainless steel, a weld metal with higher impact toughness can be obtained. The patent with publication number CN116197571B discloses a high manganese and low nickel duplex stainless steel submerged arc welding strip and flux for matched use. The alloy element composition in the welding strip is C: 0.030%-0.040%, N: 0.15%-0.27%, Cr: 25.5%-26.5%, Mo: 4.0%-4.5%, Ni: 3.5%-4.5%, Mn: 9.5%-10.5%, Ta: 0.35%-0.55%, Nb: 0.30%-0.35%, W: 0.15%-0.20%, S≤0.001%, P≤0.020%, and the balance is Fe. The Mn element is added to reduce the use of part of the Ni element to reduce the production cost of the welding strip. The ferrite and austenite are distributed more evenly, the surfacing layer has excellent mechanical properties, beautiful forming, and no defects.

[0005] In general, the current commercial duplex stainless steel wire is designed for the welding of duplex stainless steel. Usually a high content of nickel is added to the wire to ensure sufficient austenite content in the weld. The use of manganese instead of nickel and reasonable design of composition and process control to directly arc add material to obtain duplex stainless steel with a balanced two-phase ratio and excellent performance is still a technical gap.

[0006] The present invention provides a new type of high manganese and low nickel duplex stainless steel powder core wire and its preparation and use methods, and uses the powder core wire of the present invention as the raw material for additive manufacturing to prepare high manganese and low nickel duplex stainless steel metal components. Compared with the traditional duplex stainless steel production process, the new stainless steel wire of the present invention is stacked layer by layer through arc additive manufacturing, and has the characteristics of high forming efficiency, short production cycle, low cost, etc., and can obtain austenite and ferrite two-phase equilibrium structure without heat treatment. Therefore, it reflects important economic and application value for the manufacture of low nickel or even nickel-free duplex stainless steel components. The new high manganese and low nickel duplex stainless steel wire of the present invention is suitable for welding and various additive manufacturing processes of melting wires. Summary of the invention

[0007] In view of the above technical problems, the purpose of the present invention is to provide a high manganese and low nickel duplex stainless steel powder core wire and a preparation and use method thereof. Through reasonable composition design, the content of precious metal nickel in traditional duplex stainless steel wire is reduced, and the cost of duplex stainless steel powder core wire is reduced; high manganese and low nickel duplex stainless steel thin-walled structural parts are prepared by arc additive manufacturing process, and the components have good forming quality, balanced ratio of austenite and ferrite phases and good mechanical properties.

[0008] The present invention is realized by the following technical scheme: a high manganese and low nickel duplex stainless steel powder core wire, comprising a stainless steel strip and a metal powder core filled in the stainless steel strip;

[0009] The metal powder core comprises the following components in percentage by mass of the entire powder core wire: 30-40% of metallic chromium, 5-15% of chromium nitride, 25-40% of electrolytic manganese, 0-5.0% of nickel powder, 1.0-5.0% of ferrosilicon, 0.5-5.0% of ferromolybdenum, 0.5-3.0% of sodium fluoride, 0.1-1.5% of cerium oxide, and the remainder is iron powder. The sum of the percentages by mass of the above components is 100%.

[0010] Preferably, the stainless steel strip is a 430 ferritic stainless steel strip, and its chemical composition is C≤0.12%, Si≤0.75%, Mn≤1.00%, Ni≤0.60%, 16.00%≤Cr≤18.00%, P≤0.04%, S≤0.03%, and the balance is iron.

[0011] Preferably, the purity of the metallic chromium is 99% or above; the metallic chromium mainly provides the chromium element required in the additive component. Chromium is a ferrite-forming element, and the chromium-containing passivation film produced helps to improve the corrosion resistance of the deposited metal. When the chromium content is too high, more austenitizing elements are required to maintain the two-phase balance, and more chromium nitride precipitation may be formed, which has an adverse effect on the corrosion resistance and toughness of the deposited metal. Therefore, the mass fraction of metallic chromium in the present invention is controlled at 30-40%.

[0012] The nitrogen content of the chromium nitride is 12% and the chromium content is 87%; the chromium nitride transitions chromium and nitrogen elements into the additive component. Nitrogen is a strong austenitizing element and plays an important role in saving nickel, but the solubility of nitrogen is limited. Supersaturated nitrogen will form pores before it can escape from the molten pool, reducing the performance of the deposited metal. Therefore, the mass fraction of chromium nitride is controlled at 5-15%.

[0013] The purity of the electrolytic manganese is 99% or above; manganese is an austenite stabilizing element, which can produce a solid solution strengthening effect, stabilize austenite, and partially or even completely replace the nickel element in duplex stainless steel, while increasing the solubility of nitrogen in duplex stainless steel, reducing nitrogen loss and avoiding pore formation. In order to achieve a two-phase balance of austenite and ferrite in the target component, the mass fraction of electrolytic manganese in the present invention is controlled at 25-40%.

[0014] The purity of the nickel powder is 99% or above; nickel is a stable austenitizing element, and an appropriate amount of nickel element helps to improve the strength and toughness of the deposited metal. However, nickel is expensive. From the perspective of the economy of the entire welding wire production, the mass fraction of the nickel powder in the present invention is 0-5.0%.

[0015] The silicon content in the ferrosilicon is 75%; the ferrosilicon is mainly added as a deoxidizer, and plays a combined deoxidation role with manganese. The composite deoxidation product has a low melting point and a low density, and is easy to float out of the molten pool. Too much silicon content will reduce the toughness of the additive component. Therefore, the mass fraction of ferrosilicon in the present invention is 1.0-5.0%.

[0016] The molybdenum content of the ferromolybdenum is 60%; molybdenum can improve the pitting corrosion resistance of the deposited metal, but too much molybdenum will promote the formation of brittle intermetallic compounds such as σ phases, reducing the toughness of the deposited metal. The price of molybdenum is relatively high. Considering the economic efficiency of welding wire production, the mass fraction of ferromolybdenum in the present invention is limited to 0.5-5.0%.

[0017] The purity of the sodium fluoride is 99.9%; sodium fluoride is added as an arc stabilizer. - It can be combined with H generated during the deposition process + The reaction generates HF gas which escapes to prevent hydrogen embrittlement of the additive component. + It can enhance arc conductivity, improve arc stability, and reduce splashing during deposition. However, excessive sodium fluoride content will lead to decreased arc stability, increased smoke and increased splashing during deposition, so the content of sodium fluoride in the present invention is controlled to 0.5% to 3.0%.

[0018] The purity of the cerium oxide is 99.9%; an appropriate amount of cerium oxide can play a role in modification, grain refinement, and grain boundary strengthening, which helps to improve the comprehensive performance of the additive component. When too much cerium oxide is added, inclusions in the deposited metal aggregate and grow, which has an adverse effect on the performance of the additive component. Therefore, the mass fraction of cerium oxide in the present invention is 0.1% to 1.5%.

[0019] Preferably, the particle size of each component of the metal powder core is 80-120 mesh.

[0020] Preferably, the filling rate of the metal powder core in the entire powder core wire is 20-30%.

[0021] Preferably, the diameter of the powder core wire is 1.2-1.6 mm.

[0022] Preferably, the stainless steel strip has a width of 12 mm and a thickness of 0.5 mm.

[0023] The method for preparing the high manganese and low nickel duplex stainless steel powder core wire comprises the following steps:

[0024] Step 1: Weigh the metal powder core according to mass percentage, and the added components range as follows: 30-40% metallic chromium, 5-15% chromium nitride, 25-40% electrolytic manganese, 0-5.0% nickel powder, 1.0-5.0% ferrosilicon, 0.5-5.0% ferromolybdenum, 0.5-3.0% sodium fluoride, 0.1-1.5% cerium oxide, and the balance is iron powder. The sum of the mass percentages of all the above components is 100%;

[0025] Step 2: Mix all the raw materials weighed in step 1 evenly, place in an oven and dry at a temperature of 200-300°C for 2-3 hours to obtain metal powder core powder;

[0026] Step 3: Roll the cleaned and dried 430 stainless steel strip into a U-shaped groove, then add the powder dried in step 2 into the U-shaped groove at a filling rate of 25% and close it, first roll it through a forming machine to obtain a thick diameter wire, and then go through multiple drawing and reducing procedures to obtain a metal powder core wire with a diameter of 1.2 mm; the chemical composition of the above 430 steel strip is: C≤0.12%, Si≤0.75%, Mn≤1.00%, Ni≤0.60%, 16.00%≤Cr≤18.00%, P≤0.04%, S≤0.03%, and the remainder is iron.

[0027] The method for using the high manganese and low nickel duplex stainless steel powder core wire is as follows: the prepared high manganese and low nickel duplex stainless steel powder core wire is used to perform additive manufacturing of high manganese and low nickel duplex stainless steel thin-walled components according to the target additive path and number of layers using an additive manufacturing robot system using a MIG arc as a heat source.

[0028] The preferred arc additive manufacturing process parameters of the present invention are: additive current of 140-220A, additive voltage of 20-28V, deposition rate of 0.25-0.35m / min, protective gas of 100% Ar, gas flow rate of 15L / min, and interlayer temperature controlled below 150°C.

[0029] Beneficial effects: The high manganese and low nickel duplex stainless steel powder core wire provided by the present invention can be used for welding and additive manufacturing, including but not limited to arc additive manufacturing, plasma arc additive manufacturing, laser additive manufacturing, and laser-arc composite additive manufacturing, etc. In the additive manufacturing process, the arc is stable, and there is no need to clean the slag shell between layers. The component forming quality is high, the mechanical properties are good, and it has good application prospects. The specific advantages are as follows:

[0030] 1) Only a small amount of arc stabilizer component is added to the powder core wire of the present invention, and no slag shell is formed between the deposition layers, which helps to improve production efficiency.

[0031] 2) The powder core wire of the present invention uses a high content of cheap manganese element, which almost or completely replaces the expensive nickel element, greatly reducing the cost of the duplex stainless steel powder core wire.

[0032] 3) The present invention strictly controls the ratio of austenite forming elements (Mn, N) and ferrite forming elements (Cr, Mo) so that the target additive duplex stainless steel component has a balanced two-phase structure, which is beneficial for the additively manufactured component to meet the requirements of mechanical properties and corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a macroscopic image of the duplex stainless steel structural member prepared in Example 1;

[0034] Figure 2 The microstructure diagram of the duplex stainless steel structure prepared in Example 1;

[0035] Figure 3 This is a macroscopic image of the duplex stainless steel structural member prepared in Example 2;

[0036] Figure 4 The microstructure diagram of the duplex stainless steel structure prepared in Example 2;

[0037] Figure 5 This is a macroscopic image of the duplex stainless steel structural member prepared in Example 3;

[0038] Figure 6 The microstructure diagram of the duplex stainless steel structure prepared in Example 3;

[0039] Figure 7 This is a macroscopic image of the duplex stainless steel structural member prepared in Example 4;

[0040] Figure 8 This is the microstructure diagram of the duplex stainless steel structural component prepared in Example 4. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described below in conjunction with specific implementation methods.

[0042] Example 1

[0043] A high manganese and low nickel duplex stainless steel powder core wire, comprising a stainless steel strip and a metal powder core filled in the stainless steel strip;

[0044] The metal powder core comprises the following components in percentage by mass of the entire powder core wire: 30-40% of metallic chromium, 5-15% of chromium nitride, 25-40% of electrolytic manganese, 0-5.0% of nickel powder, 1.0-5.0% of ferrosilicon, 0.5-5.0% of ferromolybdenum, 0.5-3.0% of sodium fluoride, 0.1-1.5% of cerium oxide, and the remainder is iron powder. The sum of the percentages by mass of the above components is 100%.

[0045] In this embodiment, a method for preparing a high manganese and low nickel duplex stainless steel powder core wire is provided, and the steps are as follows:

[0046] Step 1: According to the pre-designed ingredients and in accordance with the mass percentage, various powders to be added are weighed, the sum of the mass percentages of the added powders being 100%, and all powder particle sizes are controlled within 80-120 meshes by sieving.

[0047] Step 2: Mix the powder weighed in step 1 evenly with a blender, and then place in an oven for drying at a temperature of 200-300° C. for 2-3 hours to obtain a metal core powder;

[0048] Step 3: Roll the cleaned and dried 430 stainless steel strip into a U-shaped groove, and fill the powder dried in step 2 into the U-shaped groove and close it. First, roll it through a forming machine to get a thick diameter wire, and then go through multiple drawing and reducing procedures to get a finished wire with a diameter of 1.2 mm.

[0049] The present embodiment provides a method for using a high manganese and low nickel duplex stainless steel powder core wire: using the high manganese and low nickel duplex stainless steel powder core wire prepared in the above embodiment, arc additive manufacturing is performed using a MIG arc as a heat source, and a reciprocating deposition method is used to stack layer by layer to obtain a high manganese and low nickel duplex stainless steel thin-walled component. Among them, the process parameters of arc additive manufacturing are: additive current is 180A, additive voltage is 26V, deposition speed is 0.30m / min, wire feeding speed is 7.7m / min, shielding gas is 100% Ar, gas flow rate is 15L / min, and interlayer temperature is controlled below 150°C.

[0050] The macroscopic morphology of the duplex stainless steel component prepared in this example is as follows: Figure 1 As shown in Figure 1, the metallurgical bonding between layers is good, there is no slag inclusion or other defects, and the molding quality is high; the microstructure is as follows Figure 2 As shown, white is austenite, gray is ferrite, and the proportion of austenite calculated by the image method is about 40%; the tensile strength of the high manganese and low nickel duplex stainless steel component in this embodiment is 631.7 MPa, and the elongation is 26.9%.

[0051] Example 2

[0052] The high manganese and low nickel duplex stainless steel powder core wire and the preparation method in this embodiment are the same as those in Example 1.

[0053] The method for using a high manganese and low nickel duplex stainless steel powder core wire in this embodiment is different from that in Example 1 in that the arc additive manufacturing process parameters are: additive current is 210A, additive voltage is 26V, deposition speed is 0.30m / min, wire feeding speed is 9.7m / min, shielding gas is 100% Ar, gas flow rate is 15L / min, and interlayer temperature is controlled below 150°C.

[0054] The macroscopic morphology of the duplex stainless steel component prepared in this example is as follows: Figure 3 As shown in FIG. 1 , compared with Example 1, the height and width of the component are increased, the metallurgical bonding between the layers is good, no slag inclusions or other defects are found, and the component has good mechanical properties, which are improved compared with Example 1. The microstructure of the additively manufactured component of this embodiment is shown in FIG. Figure 4 As shown, white is austenite, gray is ferrite, and the proportion of austenite calculated by the image method is about 45%; the tensile strength of the high manganese and low nickel duplex stainless steel component in this embodiment is 642.2MPa, and the elongation is 31.0%.

[0055] Example 3

[0056] A high manganese and low nickel duplex stainless steel powder core wire and a preparation method in this embodiment are the same as those in Example 1. The method for using a high manganese and low nickel duplex stainless steel powder core wire in this embodiment is different from that in Example 1 in that the arc additive manufacturing process parameters are: additive current is 240A, additive voltage is 26V, deposition speed is 0.30m / min, wire feeding speed is 11.7m / min, shielding gas is 100% Ar, gas flow rate is 15L / min, and interlayer temperature is controlled below 150°C.

[0057] The macroscopic morphology of the duplex stainless steel component prepared in this example is as follows: Figure 5 As shown in FIG. 1 , compared with Example 2, the height and width of the component are further increased, but the layers maintain good metallurgical bonding, no slag inclusions or other defects are found, and the component has good mechanical properties; the microstructure of the additively manufactured component of this embodiment is shown in FIG. Figure 6 As shown, white is austenite, gray is ferrite, and the proportion of austenite calculated by the image method is about 43%; the tensile strength of the high manganese and low nickel duplex stainless steel component in this embodiment is 629.1 MPa, and the elongation is 28.6%.

[0058] Example 4

[0059] The high manganese and low nickel duplex stainless steel powder core wire and preparation method in this embodiment are different from those in Embodiment 1 in that the addition ratio of electrolytic manganese powder in the metal powder core is slightly reduced.

[0060] The method for using a high manganese and low nickel duplex stainless steel powder core wire in this embodiment is the same as that in Example 2. The arc additive manufacturing process parameters are: the additive current is 210A, the additive voltage is 26V, the deposition speed is 0.3m / min, the wire feeding speed is 9.7m / min, the shielding gas is 100% Ar, the gas flow rate is 15L / min, and the interlayer temperature is controlled below 150°C.

[0061] The macroscopic morphology of the duplex stainless steel component prepared in this example is as follows: Figure 7 As shown in FIG. 1 , the metallurgical bonding between the layers is good, no slag inclusions or other defects are found, and the component has good mechanical properties. The microstructure of the additively manufactured component of this embodiment is shown in FIG. Figure 8 As shown, white is austenite, gray is ferrite, and the proportion of austenite calculated by the image method is about 40%; the tensile strength of the high manganese and low nickel duplex stainless steel component in this embodiment is 593 MPa, and the elongation is 25%.

[0062] In the above-mentioned Examples 1-3, three different heat inputs (748.8 J / mm, 873.6 J / mm, 998.4 J / mm) were used to perform arc additive manufacturing on a new type of high manganese and low nickel duplex stainless steel powder core wire of the present invention. In Example 4, powder core wires with different manganese contents were used for arc additive manufacturing. The chemical composition of the arc additive metal components of Examples 1-4 are shown in Table 1, and the mechanical properties of the arc additive metal components are shown in Table 2.

[0063] Table 1 shows the main alloying elements and their percentages (wt%) of arc additive components.

[0064] Example C Cr Ni Mn Si Mo N P S Fe Example 1 0.050 22.48 0.013 9.79 0.66 0.35 0.25 0.017 0.005 margin Example 2 0.046 22.46 0.016 9.65 0.67 0.38 0.21 0.019 0.007 margin Example 3 0.048 22.49 0.010 9.24 0.68 0.35 0.18 0.019 0.006 margin Example 4 0.052 22.54 0.014 6.99 0.61 0.35 0.22 0.020 0.005 margin

[0065] Table 2 shows the mechanical properties of arc-added metal components.

[0066] Example Tensile strength / MPa Elongation / % Example 1 631.7 26.9 Example 2 642.2 31.0 Example 3 629.1 28.6 Example 4 593.0 25.0

[0067] The metal component prepared by the high manganese and low nickel duplex stainless steel powder core wire material of the present invention when the heat input is within the range of 740-1000 J / mm has a tensile strength of 620-650 MPa and an elongation of 26-32%. The metal component prepared when the Mn content is 6-8% and the Ni content is 0-1% has a tensile strength of 580-650 MPa and an elongation of 25-30%. The metal component has good strength and plasticity, effectively reduces the nickel content of the component, saves nickel resources, and can be applied to the additive manufacturing of duplex stainless steel components in industries such as petrochemicals, ships and construction.

[0068] From the above we can see that:

[0069] 1. The present invention provides a novel high manganese and low nickel duplex stainless steel powder core wire, which greatly reduces the nickel content through the alloy design with high manganese content, and can reduce the manufacturing cost of the powder core wire.

[0070] 2. The present invention provides a new type of high manganese and low nickel duplex stainless steel powder core wire, which can directly prepare duplex stainless steel components with an austenite content of about 50% through an additive manufacturing process.

[0071] 3. The present invention provides a method for using a novel high manganese and low nickel duplex stainless steel powder core wire. The prepared components have good forming quality and mechanical properties, and the high manganese and low nickel duplex stainless steel powder core wire of the present invention exhibits a certain flexibility in composition adjustment.

[0072] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A high manganese and low nickel duplex stainless steel powder core wire, characterized in that: It includes a stainless steel strip and a metal powder core filled in the stainless steel strip; The metal powder core comprises the following components in percentage by mass of the entire powder core wire: 30-40% of metallic chromium, 5-15% of chromium nitride, 25-40% of electrolytic manganese, 0-5.0% of nickel powder, 1.0-5.0% of ferrosilicon, 0.5-5.0% of ferromolybdenum, 0.5-3.0% of sodium fluoride, 0.1-1.5% of cerium oxide, and the remainder is iron powder. The sum of the percentages by mass of the above components is 100%.

2. The high manganese and low nickel duplex stainless steel powder core wire according to claim 1, characterized in that: The stainless steel strip is a 430 ferrite stainless steel strip, and its chemical composition is C≤0.12%, Si≤0.75%, Mn≤1.00%, Ni≤0.60%, 16.00%≤Cr≤18.00%, P≤0.04%, S≤0.03%, and the balance is iron.

3. The high manganese and low nickel duplex stainless steel powder core wire according to claim 2, characterized in that: The purity of the metallic chromium is 99% or above; the nitrogen content in the chromium nitride is 12%, and the chromium content is 87%; the purity of the electrolytic manganese is 99% or above; the purity of the nickel powder is 99% or above; the silicon content in the ferrosilicon is 75%; the molybdenum content in the ferromolybdenum is 60%; the purity of the sodium fluoride is 99.9%; and the purity of the cerium oxide is 99.9%.

4. The high manganese and low nickel duplex stainless steel powder core wire according to claim 3, characterized in that: The particle size of each component of the metal powder core is 80-120 meshes.

5. The high manganese and low nickel duplex stainless steel powder core wire according to claim 4, characterized in that: The filling rate of the metal powder core in the entire powder core wire is 20-30%.

6. The high manganese and low nickel duplex stainless steel powder core wire according to claim 5, characterized in that: The diameter of the powder core wire is 1.2-1.6 mm.

7. The high manganese and low nickel duplex stainless steel powder core wire according to claim 6, characterized in that: The stainless steel strip has a width of 12 mm and a thickness of 0.5 mm.

8. A method for preparing a high manganese and low nickel duplex stainless steel powder core wire according to claim 1, 2, 3, 4, 5, 6 or 7, characterized in that: The following steps are involved: Step 1: Weigh the metal powder core according to mass percentage, and the added components range as follows: 30-40% metallic chromium, 5-15% chromium nitride, 25-40% electrolytic manganese, 0-5.0% nickel powder, 1.0-5.0% ferrosilicon, 0.5-5.0% ferromolybdenum, 0.5-3.0% sodium fluoride, 0.1-1.5% cerium oxide, and the balance is iron powder. The sum of the mass percentages of all the above components is 100%; Step 2: Mix all the raw materials weighed in step 1 evenly, place in an oven and dry at a temperature of 200-300°C for 2-3 hours to obtain metal powder core powder; Step 3: Roll the cleaned and dried 430 stainless steel strip into a U-shaped groove, then add the powder dried in step 2 into the U-shaped groove at a filling rate of 25% and close it, first roll it through a forming machine to obtain a thick diameter wire, and then go through multiple drawing and reducing procedures to obtain a metal powder core wire with a diameter of 1.2 mm; the chemical composition of the above 430 steel strip is: C≤0.12%, Si≤0.75%, Mn≤1.00%, Ni≤0.60%, 16.00%≤Cr≤18.00%, P≤0.04%, S≤0.03%, and the remainder is iron.

9. A method for using a high manganese and low nickel duplex stainless steel powder core wire according to claim 1, 2, 3, 4, 5, 6 or 7, characterized in that: The method comprises the following steps: using the prepared high manganese and low nickel duplex stainless steel powder core wire material with a MIG arc as a heat source and using an additive manufacturing robot system to perform additive manufacturing of high manganese and low nickel duplex stainless steel thin-walled components according to a target additive path and number of layers.

10. The method for using a high manganese and low nickel duplex stainless steel powder core wire according to claim 9, characterized in that: The process parameters of arc additive manufacturing are as follows: additive current is 140-220A, additive voltage is 20-28V, deposition speed is 0.25-0.35m / min, protective gas is 100% Ar, gas flow rate is 15L / min, and interlayer temperature is controlled below 150°C.

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