Cored wire for inhibiting interdiffusion of elements between steel pipe column and coating and preparation method thereof

Abstract

The invention discloses a flux-cored wire for inhibiting element interdiffusion between a steel pipe column and a coating and a preparation method thereof, and belongs to the technical field of high-temperature alloy surface engineering technology.The flux-cored wire comprises a metal type flux-cored powder and an alloy tape skin, wherein the alloy tape skin is an Inconel 625 nickel-based alloy tape skin.The powder packaging rate of the flux-cored wire is 20-25 wt.%.The invention adopts a manual TIG welding process to perform cladding on the surface of a Q345 low-alloy steel, argon can effectively isolate air around a welding molten pool, oxidation and nitridation of molten pool metal is avoided, a tungsten electrode arc is stable, the melting depth is relatively shallow, heat input in the welding process is easy to adjust, the forming quality of a cladding layer is high, full-position welding is suitable, and the invention is suitable for preparation of the cladding layer.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature alloy surface strengthening engineering technology, specifically relating to a metal-type flux-cored welding wire, and also to a method for preparing a corrosion-resistant coating for Q345 steel pipe columns using the aforementioned nickel-based alloy metal-type flux-cored welding wire. Background Technology

[0002] With the development of energy extraction technology, countries around the world have turned their attention to the development of offshore oil and gas resources. Currently, subsea pipelines are the primary means of transporting these resources, necessitating the construction of various oil production platforms, drilling rigs, and oil and gas transportation facilities at sea. During oil and gas transportation, pipelines are highly toxic and corrosive. Steel pipe columns and other structural components on oil drilling platforms, which operate underwater year-round, also face seawater erosion. The harsh operating environment means that the probability of component corrosion, pipeline leaks, and equipment failures is far higher underwater than on land. Therefore, the requirements for structural materials used in these applications are constantly increasing, demanding materials with excellent corrosion resistance and superior mechanical properties. To reduce costs, a high-performance coating is typically applied to a low-alloy steel substrate to prevent corrosion damage from corrosive media.

[0003] Nickel-based alloys are commonly used corrosion-resistant materials and are widely used on the surfaces of parts in various corrosion-resistant environments such as petroleum, chemical, and power industries. However, during the cladding process of nickel-based superalloys, the Ni and Fe elements in the cladding layer undergo a violent interdiffusion phenomenon. The entry of a large amount of Fe elements will increase the hot cracking sensitivity of the cladding layer and reduce the strength and corrosion resistance of the cladding layer.

[0004] In the prior art, such as the invention patent "Self-shielded flux-cored wire for welding T2 copper and 304 stainless steel and its preparation method" published on December 20, 2019, a self-shielded flux-cored wire for welding T2 copper and 304 stainless steel is disclosed, including a flux core and a welding skin. The flux core is composed of the following components by mass percentage: nickel powder: 50%–60%, silicon powder: 2%–9%, ​​titanium powder: 4%–8%, boron powder: 2%–4%, titanium dioxide: 1%–4%, rutile powder: 10%–13%, ferrosilicon powder: 1%–2%, aluminum-magnesium alloy powder: 2%–5%, cerium tetrafluoride: 1%–2%, calcium fluoride: 5%–9%, ​​lithium carbonate: 1%–3%, zircon sand: 1%–5%, and the sum of the mass percentages of the above components is 100%. This flux-cored wire solves the problem of poor fusion at the interface and easy formation of welding cracks when welding copper and steel.

[0005] In the prior art, such as the invention patent published on January 6, 2023, entitled "A transition metal layer for preventing interfacial diffusion, its preparation method and nickel-based alloy / steel billet assembly method," a transition metal layer for preparing a corrosion-resistant layer of nickel-steel composite plates is disclosed. The raw materials consist of the following components by mass percentage: chromium: 20%–24%, molybdenum: 6%–10%, niobium: 4%, aluminum: 0.3%–0.7%, and the balance nickel. This transition metal layer improves the surface corrosion resistance degradation caused by element diffusion during nickel-steel welding. However, the diffusion range of nickel-iron elements is still relatively large, the effect of suppressing element diffusion is poor, and macroscopic defects affecting mechanical properties are easily generated during the processing of the metal layer, leading to a decrease in workpiece quality, low processing efficiency, and high cost of the transition layer, making it difficult to mass-produce and apply. Summary of the Invention

[0006] To address the above problems, this invention provides a flux-cored welding wire and a method for preparing a highly corrosion-resistant nickel-based alloy coating on a low-alloy high-strength steel structure, which suppresses element interdiffusion during the preparation of a corrosion-resistant coating.

[0007] The technical solution of this invention is: a flux-cored welding wire for inhibiting elemental interdiffusion between steel pipe columns and coatings, comprising metallic flux-cored powder and alloy strip; the metallic flux-cored powder comprises the following components (wt.%):

[0008] Ni 48%~53%,

[0009] Cr 20%~23%,

[0010] MO 8~10%,

[0011] Nb 3.15~4.15%,

[0012] C 0.1%,

[0013] Mn 0.3%,

[0014] Si 0.3%,

[0015] Al+Ti 0.6%,

[0016] Fe 9.15%~15%;

[0017] The sum of the mass percentages of the above components is 100%.

[0018] Specifically, the alloy strip is an Inconel 625 nickel-based alloy strip.

[0019] Specifically, the flux-cored welding wire has a powder coating rate of 20~25 wt.%.

[0020] A method for preparing flux-cored welding wire that inhibits elemental interdiffusion between steel pipe columns and coatings includes the following steps:

[0021] Step 1: Weigh the following components according to their mass percentages: Ni 48%~53%, Cr 20%~23%, MO 8~10%, Nb 3.15~4.15%, C 0.1%, Mn 0.3%, Si 0.3%, Al+Ti 0.6%, and Fe 9.15%~15%. The sum of these components should be 100%. Then, heat and dry the weighed alloy powder in a vacuum tube furnace. After cooling to room temperature, the target metallic core powder is obtained.

[0022] Step 2: The flat metal strip Inconel 625 alloy strip is rolled into a U-shaped section, and then the dried metal core powder obtained in Step 1 is filled into the U-shaped welding strip and rolled into a tubular welding wire by a wire drawing machine. During the wire drawing process, the linear speed of the steel strip passing through the powder feeding process is controlled to ensure that the powder feeding amount is stable and uniform. Then, the initial welding wire is drawn layer by layer to reduce the diameter to the required specification. Finally, the surface of the welding wire is cleaned of impurities and oil stains with anhydrous ethanol or acetone.

[0023] Specifically, the flux-cored welding wire with the required diameter is cut to the appropriate length, and multiple arc cladding is performed on Q345 low carbon steel. After the cladding is completed, a corrosion-resistant nickel-based alloy coating is obtained.

[0024] Specifically, in step 1, the mixed metal core powder is placed in a vacuum tube furnace for drying at a temperature of 120℃~220℃ for 1.5h~2h, while continuously purging with 99.9% Ar gas to prevent oxidation.

[0025] Specifically, the arc cladding process parameters in step 3 are: welding current of 150A, welding voltage of 10V, and welding speed of 150cm / min to 200cm / min.

[0026] Specifically, the welding process in step 3 uses arc cladding manual TIG welding, with the shielding gas being 99.9% Ar gas and a gas flow rate of 15 L / min.

[0027] Specifically, in step 3, the thickness of the cladding layer is 2-3 mm, and the overlap rate between weld beads is 40%.

[0028] Beneficial effects of this invention:

[0029] (1) The present invention uses manual TIG welding to clad the surface of Q345 low alloy steel. Argon gas can effectively isolate the air around the weld pool and avoid oxidation and nitriding of the weld pool metal. The tungsten electrode arc is stable and the penetration depth is shallow. The heat input is easy to adjust during the welding process and the cladding layer has high forming quality. It is suitable for all-position welding and is applicable to the preparation of cladding layers.

[0030] (2) The flux-cored welding wire of the present invention has a simple production process, high controllability of composition, low production cost, and can achieve continuous production.

[0031] (3) Fe, as a major component of the low-carbon steel matrix, can suppress element diffusion between the low-carbon steel matrix and the Inconel 625 coating during welding. By reducing the compositional difference, it slows down element interdiffusion and reduces the dilution of the corrosion-resistant coating by the matrix. At the same time, as a major component of the harmful Laves phase precipitate in nickel-based superalloys, a large amount of Fe entering the cladding layer will increase the formation of the Laves phase. Controlling the Fe content in the flux-cored wire can effectively reduce the formation of the intergranular Laves phase and significantly suppress the possibility of cracking during the cladding process, thus maintaining the good corrosion resistance of the cladding layer.

[0032] (4) Ni element forms the basic structure of the cladding layer. Because it can maintain a stable austenitic structure and can combine with elements such as Al and Ti to form γ′ and γ″ phases that can enhance mechanical properties, it ensures excellent high-temperature stability, enhances the strength and corrosion resistance of the material, and enables it to withstand extreme environments such as high temperature, high pressure and corrosion without undergoing allotropic transformation.

[0033] (5) Cr reacts with O in the air or surface contact medium to form a dense oxide film, which prevents the alloy substrate from further contacting and reacting with the corrosive medium, thereby improving the corrosion resistance of the alloy coating. The presence of an appropriate amount of Cr plays a good role in solid solution strengthening, causing lattice distortion, improving the mechanical properties of the alloy, and thus enhancing the wear resistance of the coating.

[0034] (6) Mo and Nb have relatively large atomic radii and mainly play a role in solid solution strengthening in nickel-based superalloys, thereby enhancing the mechanical strength of nickel-based alloys. Furthermore, Mo and Nb can combine with C to form fine MC particles, which are distributed within the grains and at the grain boundaries, thus playing a role in dispersion strengthening and grain boundary strengthening. Attached Figure Description

[0035] Figure 1 This is a line scan of the matrix and coating elements prepared in Example 1 of the flux-cored welding wire used in this invention to suppress the interdiffusion of elements between Q345 structural components and coatings;

[0036] Figure 2This is a microstructure diagram of the coating prepared in Example 1 of the flux-cored welding wire used in this invention to suppress elemental interdiffusion between Q345 structural components and coatings;

[0037] Figure 3 This is a microstructure diagram of the coating prepared in Example 2 of the flux-cored welding wire used in this invention to suppress elemental interdiffusion between Q345 structural components and coatings.

[0038] Figure 4 This is a microstructure diagram of the coating prepared in Example 3 of the flux-cored welding wire used in this invention to suppress elemental interdiffusion between Q345 structural components and coatings. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0040] Arc cladding technology, with its advantages of high heat input, low usage requirements, ease of operation, and ability to handle various complex working conditions, has become the best solution for cladding corrosion-resistant coatings on low-carbon steel. Compared with traditional solid welding wire, metal-cored welding wire offers flexible composition control, precisely providing the target chemical composition of the weld. Through the design of the metal-cored powder composition, the redistribution of elements in the weld can be controlled, preventing the degradation of the coating's corrosion resistance due to element diffusion between the substrate and the cladding layer.

[0041] Based on this, the present invention provides a metal powder-type flux-cored welding wire for suppressing element interdiffusion during the preparation of corrosion-resistant coatings for Q345 steel pipe columns, which can effectively improve the corrosion resistance of the alloy coating while ensuring the quality of the cladding layer.

[0042] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0043] This invention discloses a metal powder-cored welding wire for low-alloy steel, comprising metal powder-cored material and Inconel 625 nickel-based alloy strip. The metal powder-cored material comprises the following components (wt.%): Ni 48%~53%, Cr 20%~23%, MO 8~10%, Nb 3.15~4.15%, C 0.1%, Mn 0.3%, Si 0.3%, Al+Ti 0.6%, Fe 9.15%~15%. The sum of the mass percentages of the above components is 100%. The powder coating rate of the metal powder-cored welding wire is 20~25 wt.%.

[0044] The preparation steps of a flux-cored welding wire to suppress elemental interdiffusion between Q345 structural components and coatings are as follows:

[0045] Step 1: Weigh the following components according to their mass percentages: Ni 48%~53%, Cr 20%~23%, MO 8%~10%, Nb 3.15%~4.15%, C 0.1%, Mn 0.3%, Si 0.3%, Al+Ti 0.6%, and Fe 9.15%~15%. The sum of these components should be 100%. Then, heat and dry the weighed alloy powder in a vacuum tube furnace. After cooling to room temperature, the target core alloy powder is obtained. The drying temperature is 120℃~220℃, and the drying time is 1.5h~2h, with 99.9% Ar gas continuously introduced.

[0046] Step 2: Flat metal strip Inconel 625 alloy strip is rolled into U-shaped sections, and then the U-shaped welding strip is filled with the dry mixed metal powder obtained in Step 1 and rolled into a tubular welding wire by a wire drawing machine. During the wire drawing process, the linear speed of the steel strip passing through the powder adding process is controlled to ensure the stable and uniform powder addition. Then, the initial welding wire is drawn layer by layer to reduce the diameter to 1.6mm. Finally, the surface of the welding wire is cleaned with anhydrous ethanol or acetone to remove impurities and oil stains, thus obtaining the metal-type flux-cored welding wire.

[0047] A method for preparing a highly corrosion-resistant nickel-based cladding layer, using a flux-cored welding wire that inhibits elemental interdiffusion between Q345 structural components and the coating, is implemented according to the following steps:

[0048] Step 1: Weigh the following components according to their mass percentages: Ni 48%~53%, Cr 20%~23%, MO 8~10%, Nb 3.15~4.15%, C 0.1%, Mn 0.3%, Si 0.3%, Al+Ti 0.6%, and Fe 9.15%~15%. The sum of these components should be 100%. Then, heat and dry the weighed alloy powder in a vacuum tube furnace. After cooling to room temperature, the target core alloy powder is obtained. The drying temperature is 120℃~220℃, and the drying time is 1.5h~2h, with 99.9% Ar gas continuously introduced.

[0049] Step 2: The flat metal strip Inconel 625 alloy strip is rolled into a U-shaped section, and then the U-shaped welding strip is filled with the dry mixed metal powder obtained in Step 1 and rolled into a tubular welding wire by a wire drawing machine. During the wire drawing process, the linear speed of the steel strip passing through the powder adding process is controlled to ensure that the amount of powder added is stable and uniform. Then, the initial welding wire is drawn layer by layer to reduce the diameter to 1.6mm. Finally, the surface of the welding wire is cleaned of impurities and oil stains with anhydrous ethanol or acetone.

[0050] Step 3: Cut the flux-cored welding wire (cut to 1.6mm diameter) to the appropriate length and perform multi-pass arc cladding on Q345 low-carbon steel. The cladding layer thickness is 2-3mm. The shielding gas is 99.9% Ar gas with a flow rate of 15L / min. Multi-pass deposition is used, with a 40% overlap between weld passes. After cladding, the desired nickel-based alloy coating is obtained.

[0051] The nickel-based alloy coating prepared by TIG arc cladding exhibits good adhesion between the substrate and the coating, resulting in excellent corrosion resistance. The shallow penetration depth of the TIG arc cladding method is suitable for coating preparation. Due to the flexibility and economy of the equipment, cladding can be performed under various complex working conditions, and manual operation is simple and convenient.

[0052] Example 1

[0053] Step 1: Weigh the following components according to their mass percentages: Ni 48%~53%, Cr 20%~23%, MO 8%~10%, Nb 3.15%~4.15%, C 0.1%, Mn 0.3%, Si 0.3%, Al+Ti 0.6%, Fe 9.15%, with the sum of these components being 100%. Then, heat and dry the weighed alloy powder in a vacuum tube furnace. After cooling to room temperature, the target core alloy powder is obtained. The drying temperature is 120℃~220℃, the drying time is 1.5h~2h, and 99.9% Ar gas is continuously introduced.

[0054] Step 2: The flat metal strip Inconel 625 alloy strip is rolled into a U-shaped section, and then the U-shaped welding strip is filled with the dry mixed metal powder obtained in Step 1 and rolled into a tubular welding wire by a wire drawing machine. During the wire drawing process, the linear speed of the steel strip passing through the powder adding process is controlled to ensure that the amount of powder added is stable and uniform. Then, the initial welding wire is drawn layer by layer to reduce the diameter to 1.6mm. Finally, the surface of the welding wire is cleaned of impurities and oil stains with anhydrous ethanol or acetone.

[0055] Step 3: Cut the flux-cored welding wire (cut to 1.6mm diameter) to the appropriate length and perform multi-pass arc cladding on Q345 low-carbon steel. The cladding layer thickness is 2-3mm. The shielding gas is 99.9% Ar gas with a flow rate of 15L / min. Multi-pass deposition is used, with a 40% overlap between weld passes. After cladding, the desired nickel-based alloy coating is obtained.

[0056] After the cladding layer is prepared, as shown in the attached document. Figure 1 EDS elemental scanning was performed on the cladding layer, with the direction from the substrate to the cladding layer. The results showed that the elemental differences between the substrate and the cladding layer were small, especially for Fe, an element with a large proportion in the substrate, and solid solution strengthening elements in the cladding layer. Interdiffusion of elements between the substrate and the cladding layer was effectively suppressed. The microstructure of the cladding layer is as follows: Figure 2 As shown, the microstructure consists of cellular and columnar crystals, exhibiting a uniform structure with fine, uniform, and dense crystals. The interface demonstrates good bonding between the cladding layer and the substrate, with few defects at the interface. Electrochemical corrosion experiments were conducted on the cladding layer in a 3.5% NaCl etching solution. The open-circuit potential reflects the material's corrosion tendency, and the current per unit area of ​​the electrode during polarization indicates the actual corrosion rate, quantifying the material's corrosion resistance. The open-circuit potential of the Q345 substrate is -0.58V, the open-circuit potential of the cladding layer is -0.40V, and the current per unit area of ​​the substrate electrode is 1.674 × 10⁻⁶. -5 A·cm -2 The current per unit area of ​​the cladding electrode is 1.505 × 10⁻⁶. -5 A·cm -2 Based on experimental results including element diffusion, microstructure, and corrosion resistance tests, the flux-cored welding wire of this invention, which suppresses element interdiffusion, can effectively slow down the element diffusion gradient in materials, and the nickel-based cladding layer prepared by this welding wire exhibits excellent corrosion resistance.

[0057] Example 2

[0058] Step 1: Weigh the following components according to their mass percentages: Ni 48%~53%, Cr 20%~23%, MO 8~10%, Nb 3.15~4.15%, C 0.1%, Mn 0.3%, Si 0.3%, Al+Ti 0.6%, and Fe 11.58% (the sum of these components should be 100%). Then, heat and dry the weighed alloy powder in a vacuum tube furnace. After cooling to room temperature, the target core alloy powder is obtained. The drying temperature is 120℃~220℃, the drying time is 1.5h~2h, and 99.9% Ar gas is continuously introduced.

[0059] Step 2: The flat metal strip Inconel 625 alloy strip is rolled into a U-shaped section, and then the U-shaped welding strip is filled with the dry mixed metal powder obtained in Step 1 and rolled into a tubular welding wire by a wire drawing machine. During the wire drawing process, the linear speed of the steel strip passing through the powder adding process is controlled to ensure that the amount of powder added is stable and uniform. Then, the initial welding wire is drawn layer by layer to reduce the diameter to 1.6mm. Finally, the surface of the welding wire is cleaned of impurities and oil stains with anhydrous ethanol or acetone.

[0060] Step 3: Cut the flux-cored welding wire (cut to 1.6mm diameter) to the appropriate length and perform multi-pass arc cladding on Q345 low-carbon steel. The cladding layer thickness is 2-3mm. The shielding gas is 99.9% Ar gas with a flow rate of 15L / min. Multi-pass deposition is used, with a 40% overlap between weld passes. After cladding, the desired nickel-based alloy coating is obtained.

[0061] After the cladding layer is prepared, its microstructure is as follows: Figure 2 As shown, the microstructure consists of cellular and columnar crystals, exhibiting a uniform structure with fine, uniform, and dense crystals. The interface demonstrates good bonding between the cladding layer and the substrate, with few defects at the interface. Electrochemical corrosion experiments were conducted on the cladding layer in a 3.5% NaCl etching solution. The open-circuit potential level reflects the material's tendency to corrode, and the current per unit area of ​​the electrode during polarization indicates the actual corrosion rate, quantifying the material's corrosion resistance. The open-circuit potential of the Q345 substrate is -0.58V, the open-circuit potential of the cladding layer is -0.42V, and the current per unit area of ​​the substrate electrode is 1.674 × 10⁻⁶. -5 A·cm -2 The current per unit area of ​​the cladding electrode is 1.575 × 10⁻⁶. -5 A·cm -2 Based on experimental results including element diffusion, microstructure, and corrosion resistance tests, the flux-cored welding wire of this invention, which suppresses element interdiffusion, can effectively slow down the element diffusion gradient in materials, and the nickel-based cladding layer prepared by this welding wire exhibits excellent corrosion resistance.

[0062] Example 3

[0063] Step 1: Weigh the following components according to their mass percentages: Ni 48%~53%, Cr 20%~23%, MO 8%~10%, Nb 3.15%~4.15%, C 0.1%, Mn 0.3%, Si 0.3%, Al+Ti 0.6%, and Fe 13.67%. The sum of these components should be 100%. Then, heat and dry the weighed alloy powder in a vacuum tube furnace. After cooling to room temperature, the target core alloy powder is obtained. The drying temperature is 120℃~220℃, and the drying time is 1.5h~2h, with 99.9% Ar gas continuously introduced.

[0064] Step 2: The flat metal strip Inconel 625 alloy strip is rolled into a U-shaped section, and then the U-shaped welding strip is filled with the dry mixed metal powder obtained in Step 1 and rolled into a tubular welding wire by a wire drawing machine. During the wire drawing process, the linear speed of the steel strip passing through the powder adding process is controlled to ensure that the amount of powder added is stable and uniform. Then, the initial welding wire is drawn layer by layer to reduce the diameter to 1.6mm. Finally, the surface of the welding wire is cleaned of impurities and oil stains with anhydrous ethanol or acetone.

[0065] Step 3: Cut the flux-cored welding wire (cut to 1.6mm diameter) to the appropriate length and perform multi-pass arc cladding on Q345 low-carbon steel. The cladding layer thickness is 2-3mm. The shielding gas is 99.9% Ar gas with a flow rate of 15L / min. Multi-pass deposition is used, with a 40% overlap between weld passes. After cladding, the desired nickel-based alloy coating is obtained.

[0066] After the cladding layer is prepared, its microstructure is as follows: Figure 3 As shown, the microstructure consists of cellular and columnar crystals, exhibiting a uniform structure with fine, uniform, and dense crystals. The interface demonstrates good bonding between the cladding layer and the substrate, with few defects at the interface. Electrochemical corrosion experiments were conducted on the cladding layer in a 3.5% NaCl etching solution. The open-circuit potential level reflects the material's tendency to corrode, and the current per unit area of ​​the electrode during polarization indicates the actual corrosion rate, quantifying the material's corrosion resistance. The open-circuit potential of the Q345 substrate is -0.58V, the open-circuit potential of the cladding layer is -0.47V, and the current per unit area of ​​the substrate electrode is 1.674 × 10⁻⁶. -5 A·cm -2 The current per unit area of ​​the cladding electrode is 1.314 × 10⁻⁶. -5 A·cm -2 Based on experimental results including element diffusion, microstructure, and corrosion resistance tests, the flux-cored welding wire of this invention, which suppresses element interdiffusion, can effectively slow down the element diffusion gradient in materials, and the nickel-based cladding layer prepared by this welding wire exhibits excellent corrosion resistance.

[0067] The flux-cored welding wire of this invention, which suppresses the interdiffusion of elements between Q345 structural components and coatings, is used to prepare corrosion-resistant coatings. The coatings are free from obvious welding defects such as cracks, pores, and slag inclusions, and have excellent coating forming quality with less welding arc smoke.

[0068] Regarding the information disclosed in this case, the following points need to be clarified:

[0069] (1) The accompanying drawings of the embodiments disclosed in this case only involve the structures involved in the embodiments disclosed in this case; other structures can refer to the general design.

[0070] (2) Where there is no conflict, the embodiments and features disclosed in this case can be combined with each other to obtain new embodiments;

[0071] The above are merely specific embodiments disclosed in this case, but the scope of protection of this disclosure is not limited thereto. The scope of protection disclosed in this case shall be determined by the scope of protection of the claims.

Claims

1. A flux-cored welding wire for inhibiting elemental interdiffusion between steel pipe columns and coatings, characterized in that, It includes metallic flux-cored powder and alloy strip; the alloy strip is Inconel 625 nickel-based alloy strip, and the flux-cored wire powder coating rate is 20~25 wt.%; the metallic flux-cored powder includes the following components (wt.%): Ni 48%~53%, Cr 20%~23%， MO 8~10%, Nb 3.15~4.15%, C 0.1%， Mn 0.3%, Si 0.3%, Al+Ti 0.6%, Fe 9.15%~15%; The sum of the mass percentages of the above components is 100%; The 20%~23% Cr, 3.15~4.15% Nb and 9.15%~15% Fe form a synergistic composition system. Combined with a fixed composite deoxidation system of Al+Ti=0.6% and an impurity control combination of 0.3% Mn, 0.3% Si and 0.1% C, it is compatible with Inconel 625 nickel-based alloy strip and can suppress Ni-Fe interdiffusion when used for arc cladding of Q345 steel pipe columns.

2. A method for preparing flux-cored welding wire that inhibits interdiffusion of elements between steel pipe columns and coatings, used to prepare the flux-cored welding wire for inhibiting interdiffusion of elements between steel pipe columns and coatings as described in claim 1, characterized in that, Includes the following steps: Step 1: Weigh the following components according to their mass percentages: Ni 48%~53%, Cr 20%~23%, MO 8~10%, Nb 3.15~4.15%, C 0.1%, Mn 0.3%, Si 0.3%, Al+Ti 0.6%, and Fe 9.15%~15%. The sum of these components should be 100%. Then, heat and dry the weighed alloy powder in a vacuum tube furnace. After cooling to room temperature, the target metallic core powder is obtained. Step 2: The flat metal strip alloy strip is rolled into a U-shaped section, and then the U-shaped welding strip is filled with the dry metal core powder obtained in Step 1 and rolled into a tubular welding wire by the wire drawing machine; then the initial welding wire is drawn layer by layer to reduce the diameter to the required specification, and finally the surface of the welding wire is cleaned of impurities and oil stains with anhydrous ethanol or acetone. Step 3: Cut the flux-cored welding wire to the required diameter and length, and perform multi-pass arc cladding on Q345 low-carbon steel. After cladding, a corrosion-resistant nickel-based alloy coating is obtained. The arc cladding process parameters are: welding current 150A, welding voltage 10V, welding speed 150cm / min~200cm / min; the welding process adopts manual TIG arc cladding welding, the shielding gas is 99.9% Ar gas, and the gas flow rate is 15L / min. The thickness of the cladding layer is 2-3 mm, and the overlap rate between weld beads is 40%.

3. The method for preparing flux-cored welding wire to suppress elemental interdiffusion between steel pipe columns and coatings according to claim 2, characterized in that, Cut the flux-cored welding wire to the required diameter to the appropriate length, and perform multiple arc cladding on Q345 low carbon steel. After cladding, a corrosion-resistant nickel-based alloy coating is obtained.

4. The method for preparing flux-cored welding wire to suppress elemental interdiffusion between steel pipe columns and coatings according to claim 2, characterized in that, In step 1, the mixed metal core powder is placed in a vacuum tube furnace for drying at a temperature of 120℃~220℃ for 1.5h~2h, while continuously introducing 99.9% Ar gas to prevent oxidation.

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