A flux-cored wire for marine pipe structure additive and a method for preparing and using the same

Abstract

The application provides a kind of marine engineering pipe structural member additive flux-cored wire and its preparation, use method, flux-cored wire is constituted by metal powder core and stainless steel strip, metal powder core is wrapped in stainless steel strip, stainless steel strip is 304L stainless steel strip, the mass fraction of each component of metal powder core is as follows: chromium powder 17.2-19%, molybdenum powder 11.8-12.2%, manganese powder 4.2-4.6%, silicon powder 2.26-2.46%, sodium fluoride 0.8-1.2%, lanthanum oxide 0.1-0.2%, the rest is iron powder, the sum of the mass percentage of the above component content is 100%, and the filling rate is 20-25wt%.The flux-cored wire preparation cycle is short, the production efficiency is high, continuous production can be realized, and it can be used for the additive manufacturing of duplex stainless steel structural member.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wire-arc additive manufacturing, and particularly relates to a flux-cored wire for additive manufacturing of a duplex stainless steel marine pipe structural part and a preparation and use method thereof. BACKGROUND

[0002] Additive manufacturing technology is a technology for manufacturing solid parts by gradually accumulating materials, and is a "bottom-up" manufacturing method compared with the traditional material removal-chip removal machining technology.

[0003] Duplex stainless steel has excellent strength and toughness, corrosion resistance and good weldability, and its excellent performance is due to the 1:1 ratio of ferrite and austenite two-phase ratio. The close two-phase ratio effectively combines the high strength and chloride stress corrosion resistance of ferritic stainless steel and the excellent toughness and weldability of austenitic stainless steel, and is suitable for the manufacture of pipeline structural parts in seawater environment.

[0004] At present, the manufacturing cost of duplex stainless steel structural parts prepared by traditional processing technology is very high, especially for complex-shaped duplex stainless steel parts, which takes a long time and has a complex process in casting or subtractive machining. At the same time, the sigma phase formed during duplex stainless steel casting must be eliminated by heat treatment. In addition, compared with austenitic stainless steel, the manufacturing cost of duplex stainless steel components prepared by plastic processing is very high. Therefore, it is imperative to study the additive manufacturing technology for processing complex structural parts of duplex stainless steel with excellent corrosion resistance and better mechanical properties.

[0005] Invention patent ZL202110648013.X discloses a duplex stainless steel wire for arc additive manufacturing, which is composed of a metal powder core and a steel strip. The metal powder core includes chromium powder with a mass fraction of 55%-90% and nickel powder with a mass fraction of 0%-5.5%, and other components are the balance of powder. The duplex stainless steel wire for arc additive manufacturing provided by the invention can directly arc additively manufacture a duplex stainless steel component with an austenite content of about 50%, which meets the standard requirements.

[0006] However, China is a country lacking of nickel and stainless steel scrap, and the rapid development of the stainless steel industry will inevitably increase the tension of raw material resources supply.

[0007] Under the background of today's changing era, it is necessary to design an economic duplex stainless steel additive manufacturing wire, reduce the cost and selling price of duplex stainless steel by reducing the nickel or molybdenum content in the steel, make the duplex stainless steel marine pipe structural part additive manufacturing self-controllable, and significantly improve the organization and performance of the additive manufacturing duplex stainless steel. SUMMARY

[0008] To solve the above technical problems, the application provides a flux-cored wire for additive manufacturing of marine pipe structural parts and a preparation and use method thereof, the raw material of the flux-cored wire is self-controllable, the preparation period is short, the production efficiency is high, continuous production can be realized, and the flux-cored wire is suitable for additive manufacturing of duplex stainless steel structural parts.

[0009] The technical scheme of the application is as follows: a flux-cored wire for additive manufacturing of marine pipe structural parts is composed of a metal powder core and a stainless steel strip, the metal powder core is wrapped in the stainless steel strip, the stainless steel strip is a 304L stainless steel strip, and the mass fraction of each component of the metal powder core is as follows: chromium powder 17.2-19%, molybdenum powder 11.8-12.2%, manganese powder 4.2-4.6%, silicon powder 2.26-2.46%, sodium fluoride 0.8-1.2%, lanthanum oxide 0.1-0.2%, and the rest is iron powder, and the sum of the mass percentages of the above components is 100%.

[0010] Preferably, the mass fraction of each component is as follows: chromium powder 17.2-19%, molybdenum powder 12%, manganese powder 4.4%, silicon powder 2.46%, sodium fluoride 1%, lanthanum oxide 0.1-0.2%, and the rest is iron powder, and the sum of the mass percentages of the above components is 100%.

[0011] Preferably, the diameter of the flux-cored wire is 1.2-2 mm.

[0012] Preferably, the filling rate of the metal powder core is 20-25 wt%.

[0013] The preparation method of the flux-cored wire for additive manufacturing of marine pipe structural parts comprises the following steps:

[0014] Step 1: chromium powder, molybdenum powder, manganese powder, silicon powder, sodium fluoride, lanthanum oxide and iron powder are weighed according to the mass percentage, mixed uniformly, placed in a tube furnace, inert gas is continuously introduced, and after baking at high temperature for a period of time, the mixture is cooled to room temperature;

[0015] Step 2: the 304L stainless steel strip is placed on the strip placing machine of the wire forming machine, the 304L stainless steel strip is rolled into a U-shaped groove through the pressure groove of the forming machine, and the powder obtained in step 1 is filled into the U-shaped groove;

[0016] Step 3: the U-shaped groove is closed by the forming machine, and the primary wire is prepared after passing through the closed forming roller, the wire is wiped clean with a decontaminating agent and then drawn, the diameter is gradually reduced until the desired diameter, and the wire is wiped clean again with a decontaminating agent to remove oil stains on the wire;

[0017] Step 4: the wire is straightened, coiled into a disc, sealed and packaged by the wire drawing machine, and the preparation is completed.

[0018] Preferably, in step 1, the inert gas is argon.

[0019] Preferably, in step 1, after baking at 200-300 DEG C for 2-3 hours, cooling to room temperature

[0020] Preferably, in step 3, the decontaminant is acetone or anhydrous ethanol.

[0021] The method for using the marine pipe structure additive flux-cored wire comprises the following steps: loading the prepared metal type flux-cored wire into a full-automatic welding robot, planning a welding path, determining a layer height, inputting a program into the welding machine, running a welding machine command, and adopting MIG welding as a heat source to perform additive manufacturing.

[0022] Preferably, the process parameters of the MIG welding are as follows: a welding speed is 0.21-0.25 m / min; a welding gun is lifted by 1.5-2 mm per layer; and a protective gas is 100% argon.

[0023] The present application has the following beneficial effects:

[0024] 1. The flux-cored wire provided by the present application has a short preparation period, high production efficiency, and can realize continuous production, and can be used for additive manufacturing of duplex stainless steel structural parts.

[0025] 2. The duplex stainless steel wire material for arc additive manufacturing provided by the present application can directly arc additively manufacture a duplex stainless steel component with an austenite content of about 50%, which meets the standard requirements.

[0026] 3. The duplex stainless steel wire material for arc additive manufacturing provided by the present application has reduced chromium content and nickel content compared with traditional duplex stainless steel welding wire, which is beneficial to the duplex stainless steel component having a lower cost and making the raw materials controllable.

[0027] 4. The present application provides a method for preparing a duplex stainless steel component by additive manufacturing technology; in the additive manufacturing process, spatter is less, the arc is stable, the weld formation is beautiful, and there is basically no collapse phenomenon; based on MIG welding, the duplex stainless steel component manufactured by using the metal type flux-cored wire for additive manufacturing has excellent mechanical properties. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The stress-strain curve of the duplex stainless steel component prepared in Example 1;

[0029] Figure 2 The typical microstructure diagram of the arc additive duplex stainless steel component obtained in Example 1;

[0030] Figure 3 The stress-strain curve of the duplex stainless steel component prepared in Example 2;

[0031] Figure 4 The typical microstructure diagram of the arc additive duplex stainless steel component obtained in Example 2;

[0032] Figure 5 Stress strain curve for duplex stainless steel component prepared in Example 3;

[0033] Figure 6 Chemical composition table of 304L stainless steel strip used in Examples 1-3 (mass %);

[0034] Figure 7 Typical microstructure of ER2209 wire arc additive duplex stainless steel component. DETAILED DESCRIPTION

[0035] The application will be further described below with examples.

[0036] A flux-cored wire for additive manufacturing of offshore pipe structure is composed of a metal powder core and a stainless steel strip, the metal powder core is wrapped in the stainless steel strip, the stainless steel strip is a 304L stainless steel strip, the mass fraction of each component of the metal powder core is: chromium powder 17.2-19%, molybdenum powder 11.8-12.2%, manganese powder 4.2-4.6%, silicon powder 2.26-2.46%, sodium fluoride 0.8-1.2%, lanthanum oxide 0.1-0.2%, and the rest is iron powder, the sum of the mass percentages of the above component contents is 100%.

[0037] The diameter of the flux-cored wire is 1.2-2mm, and the filling rate of the metal powder core is 20-25wt%.

[0038] The preparation method of the flux-cored wire for additive manufacturing of offshore pipe structure comprises the following steps:

[0039] Step 1, according to the mass percentage, the corresponding mass of chromium powder, molybdenum powder, manganese powder, silicon powder, sodium fluoride, lanthanum oxide and iron powder is weighed respectively, and after mixing uniformly, it is placed in a tube furnace, argon is continuously introduced, and after baking at 200-300℃ for 2-3h, it is cooled to room temperature;

[0040] Step 2, place the 304L stainless steel strip on the strip placing machine of the wire forming machine, and roll the 304L stainless steel strip into a U-shaped groove through the pressure groove of the forming machine, and fill the flux-cored powder obtained in step 1 into the U-shaped groove;

[0041] Step 3, the forming machine makes the U-shaped groove roll and close, and after passing through the closed forming roller, the primary wire is prepared, and then the decontaminating agent is used to wipe clean and then draw, and after gradually reducing the diameter, the desired diameter is obtained, and then the decontaminating agent is used to wipe clean and wipe off the oil stains on the wire;

[0042] Step 4, the wire is straightened, coiled into a disc, sealed and packaged by the wire drawing machine, and the preparation is completed.

[0043] The decontaminating agent in step 3 is acetone or anhydrous ethanol.

[0044] The method for using the offshore pipe structure additive flux-cored wire comprises the following steps: loading the prepared metal type flux-cored wire into a full-automatic welding robot, planning a welding path, determining a layer height, inputting a program into the welding machine, and running the welding machine command.

[0045] The process parameters of the MIG welding are as follows: a welding speed is 0.21 m / min-0.25 m / min; a welding gun is lifted by 1.5 mm-2 mm per layer; and a protective gas is 100% argon.

[0046] The mechanism of the chemical component design of the welding wire is as follows:

[0047] The welding wire component design combines the Schaeffler diagram of the duplex stainless steel, and the content of Cr elements and Ni elements is reduced according to the calculation formula of the Cr and Ni equivalent shown above, so that the duplex stainless steel arc additive flux-cored wire is designed.

[0048] The transition elements in the welding wire include Cr, Ni, Mo, Mn, Si and RE. The Cr element is the most important element for corrosion resistance of the duplex stainless steel, the chromium can form a dense Cr2O3 film on the surface, which effectively prevents the penetration of the corrosion medium, and the chromium has another main effect on the duplex stainless steel, that is, promoting the formation of ferrite and reducing the austenite phase area. The Cr content in the 2205 duplex stainless steel is about 22%, and the sigma phase is precipitated in the structure at high temperature, the sigma phase is a typical iron-chromium compound, and the sigma phase is relatively brittle and hard, the precipitation of the sigma phase in the duplex stainless steel can seriously reduce the chromium content at the grain boundary of the matrix structure, and can reduce the corrosion resistance of the duplex stainless steel and cause embrittlement.

[0049] Ni is a strong austenite forming element, in the phase diagram, nickel can expand the austenite phase area, and with the increase of the nickel content in the duplex stainless steel, the gamma-alpha transition temperature also decreases, so that the austenite can exist stably at room temperature under rapid cooling.

[0050] Mo element is one of the most important alloying elements of duplex stainless steel. Its effect in duplex stainless steel is similar to that of chromium element, and molybdenum can also reduce the austenite phase area, which means that molybdenum can promote the formation of ferrite.

[0051] The Mn and Si elements can effectively remove impurity elements such as S, O and P in the weld, and a small amount of silicon added in the steel can significantly improve the oxidation resistance; the rare earth element lanthanum is added to play the role of modification and purification. In addition, sodium fluoride is added as an arc stabilizer to reduce the spatter rate of the metal type flux-cored wire during the accumulation process and improve the welding process of the flux-cored wire.

[0052] Based on the Schaeffler diagram and the relationship between austenite-forming elements and ferrite-forming elements, an economical duplex stainless steel was designed, containing a flux-cored wire composition with low Cr equivalent and even lower Ni equivalent. The alloying elements in the deposited metal of the structural components are obtained from stainless steel strip and added alloy powder. The content of each alloying element in the flux-cored wire of the transition layer metal-type welding wire was calculated using the proportion of alloying elements in the alloy powder, the element transition coefficient, the wire filling rate, and the alloying element content of the stainless steel strip. The calculation formula is as follows:

[0053] (Formula 1)

[0054] Where ω1 is the content of each alloy element in the "cored core" of the transition layer metal-cored welding wire to be calculated; α is the theoretical element content of the transition layer deposited metal; and θ is the filling rate of the metal-cored welding wire. w 2 represents the content of alloying elements in the outer steel strip; μ represents the transition coefficient of the alloying element; and η represents the mass percentage of the element in the alloy powder.

[0055] Example 1

[0056] The preparation method of flux-cored welding wire for additive manufacturing of offshore pipeline structural components in this embodiment includes the following steps:

[0057] Step 1: Weigh out the following components by mass percentage: 17.2% chromium powder, 12% molybdenum powder, 4.4% manganese powder, 2.46% silicon powder, 1% sodium fluoride, 0.15% lanthanum oxide, and the remainder is iron powder. The sum of the mass percentages of the above components is 100%.

[0058] Step 2: Mix all the raw materials weighed in Step 1 evenly and place them in a tube furnace. Keep the furnace at 200°C for 2 hours under the condition of continuous argon gas flow.

[0059] Step 3: Take a 7mm wide and 0.3mm thick 304L stainless steel strip (composition as follows) Figure 6 The components shown in the table (the sum of the mass percentages of the components is 100%) are placed on the feeding machine of the welding wire forming machine. The low carbon steel strip is rolled into a U-shaped groove by the pressing groove of the forming machine. The flux-cored powder obtained in step 2 is placed into the U-shaped groove. The filling rate of the flux-cored powder is controlled at 20-25 wt%. Then, the forming machine is used to press and close the U-shaped groove. The wire is wiped clean with acetone or anhydrous ethanol and then drawn until the diameter is 1.2 mm. The oil on the welding wire is wiped with a cotton cloth soaked in acetone or anhydrous ethanol. Finally, the welding wire is straightened, coiled into a disc, and sealed and packaged by the wire drawing machine to complete the preparation of the metal flux-cored welding wire.

[0060] The use method is as follows: the prepared metal type flux-cored wire is loaded into a full-automatic welding robot, a welding path is planned, a layer height is determined, and a program is written and input into the welding machine, a running welding machine command is adopted, MIG welding is used as a heat source to perform additive manufacturing, and thus the duplex stainless steel component is obtained, the operation of the full-automatic welding robot is a conventional technology, and thus the specific process will not be repeatedly described, wherein the specific parameters of the welding process are as follows: the welding speed is 0.21-0.25 m / min; the welding gun is lifted by 1.5-2 mm per layer; and the protective gas is 100% Ar.

[0061] The stress-strain test curve result of the duplex stainless steel component prepared in the embodiment is shown in Figure 1 , the tensile strength of the duplex stainless steel component is 761.0 Mpa, and the typical microstructure of the obtained arc additive duplex stainless steel component is shown in Figure 2 , quantitative analysis result shows that the austenite content in the obtained arc additive duplex stainless steel component is about 43%, which is within the range of 35-65% specified in NORSOK M-630.

[0062] Example 2

[0063] The preparation method of the flux-cored wire for additive manufacturing of the offshore pipe structure in the embodiment is as follows:

[0064] Step 1: chromium powder 18.5%, molybdenum powder 12%, manganese powder 4.4%, silicon powder 2.46%, sodium fluoride 1%, lanthanum oxide 0.1%, and the rest is iron powder are weighed according to the mass percentage, and the sum of the mass percentages of the component contents is 100%; Step 2: all the raw materials weighed in step 1 are uniformly mixed and placed in a tube furnace, and argon is continuously introduced under the condition of 200℃ for 2h;

[0065] Step 3: a 304L stainless steel strip with a width of 7mm and a thickness of 0.3mm (the composition is shown in the Figure 6 table, and the sum of the mass percentages of the component contents is 100%) is placed on the strip placing machine of the wire forming machine, the low-carbon steel strip is rolled into a U-shaped groove through the pressure groove of the forming machine, the flux-cored powder obtained in step 2 is placed in the U-shaped groove, the filling rate of the flux-cored powder is controlled to be 20-25wt%, then the U-shaped groove is closed by rolling with the forming machine, and the U-shaped groove is wiped clean with acetone or anhydrous ethanol, and then drawing is performed until the diameter is 1.2mm, the oil stains on the wire are wiped with cotton cloth dipped in acetone or anhydrous ethanol, and finally the wire is straightened, coiled into a disc, sealed and packaged by the wire drawing machine, and the preparation of the metal type flux-cored wire is completed.

[0066] Usage method: Load the prepared metal-cored welding wire into the fully automatic welding robot, plan the welding path, determine the layer height, and input the program into the welding machine. Run the welding machine command and use MIG welding as the heat source for additive manufacturing to obtain the duplex stainless steel component of the present invention. The specific parameters of the welding process are: welding speed of 0.21~0.25m / min; lifting of the welding torch for each layer of 1.5~2mm; shielding gas of 100%Ar.

[0067] The stress-strain test curves of the duplex stainless steel components prepared by this invention are as follows: Figure 3 As shown, the tensile strength of the duplex stainless steel component is 761.7 MPa, and the typical microstructure of the obtained arc-additive duplex stainless steel component is as follows. Figure 4 Quantitative analysis results show that the austenite content in the obtained arc-additive duplex stainless steel component is about 39%, which is within the range of 35-65% specified in NORSOK M-630.

[0068] Example 3

[0069] The preparation method of flux-cored welding wire for additive manufacturing of offshore pipeline structural components in this embodiment includes the following steps:

[0070] Step 1: Weigh out the following components by mass percentage: 19% chromium powder, 12% molybdenum powder, 4.4% manganese powder, 2.46% silicon powder, 1% sodium fluoride, 0.2% lanthanum oxide, and the remainder is iron powder. The sum of the mass percentages of the above components is 100%.

[0071] Step 2: Mix all the raw materials weighed in Step 1 evenly and place them in a tube furnace. Keep the furnace at 200°C for 2 hours under the condition of continuous argon gas flow.

[0072] Step 3: Take a 7mm wide and 0.3mm thick 304L stainless steel strip (composition as follows) Figure 6 The components shown in the table (the sum of the mass percentages of the components is 100%) are placed on the feeding machine of the welding wire forming machine. The low carbon steel strip is rolled into a U-shaped groove by the pressing groove of the forming machine. The flux-cored powder obtained in step 2 is placed into the U-shaped groove. The filling rate of the flux-cored powder is controlled at 20-25 wt%. Then, the forming machine is used to press and close the U-shaped groove. The wire is wiped clean with acetone or anhydrous ethanol and then drawn until the diameter is 1.2 mm. The oil on the welding wire is wiped with a cotton cloth soaked in acetone or anhydrous ethanol. Finally, the welding wire is straightened, coiled into a disc, and sealed and packaged by the wire drawing machine to complete the preparation of the metal flux-cored welding wire.

[0073] Use method: the prepared metal type flux-cored wire is loaded into the full-automatic welding robot, the welding path is planned, the layer height is determined, and the program is written and input into the welding machine, the welding machine is run, MIG welding is used as the heat source to carry out additive manufacturing, and the duplex stainless steel component of the application is obtained, wherein the specific parameters of the welding process are: the welding speed is 0.21-0.25 m / min; the welding gun is lifted by 1.5-2 mm per layer; and the protective gas is 100% Ar.

[0074] The stress-strain test curve result of the duplex stainless steel component prepared in the application is as shown in the figure, and the tensile strength of the duplex stainless steel component is 748.5 Mpa. Figure 5

[0075] The technical scheme of the application, the flux-cored wire used is compared with the solid wire, the alloy elements in the flux-cored wire are transferred to the weld in the welding process through the flux in the steel shell, so it is convenient to adjust the content of the alloy composition, and the solid wire needs to be remelted every time the alloy composition is adjusted; and in the drawing process, some ingots have poor drawability and are not easy to draw into the required wire.

[0076] The arc additive duplex stainless steel wire material of the application can control the austenite content in the duplex stainless steel component in the range of about 50%.

[0077] As a comparison, see Figure 7 Taking the ER2209 wire as an example, the austenite content in the arc additive duplex stainless steel component is about 78%, which exceeds the range of 35-65% specified in NORSOK M-630.

[0078] The application adopts MIG welding as the heat source for preparing the duplex stainless steel component, compared with TIG welding, the MIG welding adopts the wire as the electrode, the wire and the current density are large, the wire melting efficiency is high, the welding deformation is small, the productivity is high, and it is suitable for automatic production, and in the welding process, a small amount of tungsten is melted and evaporated, and the tungsten particles entering the molten pool will cause tungsten clamping and affect the welding quality.

[0079] Based on MIG welding, the application uses the metal type flux-cored wire as the raw material for preparing the duplex stainless steel component, and has the following advantages: high production efficiency, good component formability, no need for too many devices in the steel pipe preparation process, and low cost; small spatter in the welding process, and stable droplet transition.

[0080] As can be seen from the above,

[0081] 1. The flux-cored wire provided by the application has a short preparation period, high production efficiency, and can realize continuous production, and can be used for additive manufacturing of duplex stainless steel structural components;

[0082] ​2. The duplex stainless steel wire for electric arc additive manufacturing provided by the present application can directly electric arc additive manufacture a duplex stainless steel component with an austenite content of about 50%, which meets the standard requirements;

[0083] 3. The duplex stainless steel wire for electric arc additive manufacturing provided by the present application has a reduced chromium content and a reduced nickel content compared to conventional duplex stainless steel welding wires, which is beneficial to the duplex stainless steel component to have a lower cost and make the raw materials controllable;

[0084] 4. The present application provides a method for preparing a duplex stainless steel component by additive manufacturing technology; in the additive manufacturing process, the present application has less spatter, a stable electric arc, a beautiful weld formation and basically no collapse phenomenon; based on MIG welding, the duplex stainless steel component manufactured by using metal type flux-cored wire additive manufacturing has excellent mechanical properties.

[0085] The present application is not limited to the above embodiments, and based on the technical solutions disclosed in the present application, those skilled in the art can make some substitutions and modifications to some technical features without creative labor according to the disclosed technical content, and these substitutions and modifications are all within the protection scope of the present application.

Claims

1. A flux-cored wire for offshore tubular structure additive manufacturing, consisting of a metal powder core and a stainless steel strip, the metal powder core being wrapped in the stainless steel strip, characterized in that, The stainless steel strip is a 304L stainless steel strip, and the mass fraction of each component of the metal powder core is: chromium powder 17.2-19%, molybdenum powder 11.8-12.2%, manganese powder 4.2-4.6%, silicon powder 2.26-2.46%, sodium fluoride 0.8-1.2%, lanthanum oxide 0.1-0.2%, and the rest is iron powder, and the sum of the mass percentages of the above component contents is 100%; the filling rate of the metal powder core is 20-25wt%.

2. The flux-cored welding wire for additive manufacturing of marine pipe structures according to claim 1, characterized in that The mass fraction of each component of the metal powder core is: chromium powder 17.2-19%, molybdenum powder 12%, manganese powder 4.4%, silicon powder 2.46%, sodium fluoride 1%, lanthanum oxide 0.1-0.2%, and the rest is iron powder, and the sum of the mass percentages of the above component contents is 100%.

3. The flux-cored welding wire for additive manufacturing of marine pipe structures according to claim 1, characterized in that The diameter of the flux-cored wire is 1.2-2mm.

4. The method of making an additive flux cored welding wire for offshore tubular structures according to claim 1, characterized in that, It comprises the following steps: Step 1, according to the mass percentage, respectively take the corresponding mass of chromium powder, molybdenum powder, manganese powder, silicon powder, sodium fluoride, lanthanum oxide and iron powder, mix uniformly and place in a tube furnace, continuously pass inert gas, and bake at high temperature for a period of time, then cool to room temperature; Step 2, place the 304L stainless steel strip on the strip placing machine of the wire forming machine, roll the 304L stainless steel strip into a U-shaped groove through the pressure groove of the forming machine, and fill the powder obtained in step 1 into the U-shaped groove; Step 3, the forming machine makes the U-shaped groove roll and close, and after passing through the closed forming roller, the primary wire is made, and then the decontaminant is used to wipe clean and then draw, and after gradually reducing the diameter, it is the required diameter, and then the decontaminant is used to wipe clean and wipe the oil stains on the wire; Step 4, straighten the wire through the wire drawing machine, and then disc into a disc, seal and package, and complete the preparation.

5. A method of producing an additive flux cored wire for a marine pipe structure according to claim 4, characterized in that, In step 1, the inert gas is argon.

6. A method of producing an additive flux cored wire for a marine pipe structure according to claim 4, characterized in that, In step 1, after baking at 200-300℃ for 2-3h, cool to room temperature.

7. The method of claim 4, wherein the flux-cored welding wire for the marine pipe structure is prepared by adding 0.1 to 0.3% of the rare earth element to the flux-cored welding wire for the marine pipe structure. The decontaminant in step 3 is acetone or anhydrous ethanol.

8. The method of using an additive flux cored welding wire for offshore tubular structures according to claim 1, characterized in that, The prepared metal type flux-cored wire is loaded into a full-automatic welding robot, and the welding path is planned, the layer height is determined, and the program is written and input into the welding machine, the welding machine command is run, and MIG welding is used as the heat source for additive manufacturing.

9. A method of using an additive flux cored welding wire for offshore tubular structures according to claim 8, characterized in that, The process parameters of the MIG welding are: welding speed is 0.21-0.25m / min; the welding gun is lifted by 1.5-2mm per layer; The shielding gas is 100% argon.

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