Stainless steel flux-cored wire and preparation method thereof

Abstract

The invention relates to a stainless steel flux-cored wire and a preparation method thereof, and relates to the technical field of flux-cored wires. The stainless steel flux-cored wire comprises a stainless steel strip and a double-layer flux core, the stainless steel strip is filled with the double-layer flux core, and the filling amount of the double-layer flux core accounts for 20-25% of the total mass of the stainless steel flux-cored wire; the double-layer flux core comprises a rapid reaction layer and an alloy transition layer, the rapid reaction layer comprises an oil stain oxidizing agent, the oil stain oxidizing agent comprises a high-temperature decomposition type organic matter and an inorganic composition, and the inorganic composition comprises copper oxide and ferric oxide with the mass ratio being (1-1.5): 1. The high-temperature decomposition type organic matter comprises polytetrafluoroethylene micro powder and trisodium citrate according to the mass ratio of 1: (3-5), and the alloy transition layer comprises 316L stainless steel powder, metal powder, silicon powder, niobium carbide and rare earth oxide. The invention can effectively avoid hydrogen embrittlement caused by diffusible hydrogen easily formed by compounds in anti-rust oil remaining on the surface of the welding wire during welding and entering a welding seam.

Description

Technical Field

[0001] The invention relates to the technical field of flux-cored welding wires, and in particular to a stainless steel flux-cored welding wire, a preparation method and application thereof. Background Art

[0002] As the fourth generation welding material, flux-cored welding wire has the advantages of strong adaptability, easy alloying, high deposition rate, good process performance and mechanical properties, high productivity and low cost, and is widely used in shipbuilding, marine engineering, bridges, engineering machinery, petrochemicals, energy equipment and pressure vessels. Flux-cored welding wire is mainly made of steel strip wrapped with powder, rolled by a rolling mill and drawn by a wire drawing machine.

[0003] Hydrogen pores are a type of fine crack defect in welds that can generate huge stress. During the welding process, the internal stress of the hydrogen pores and the external stress interweave, and the cracks gradually expand, which is prone to "hydrogen embrittlement", thus affecting the quality of the weld. The diffuse hydrogen in the weld comes from a wide range of sources. In actual welding operations, hydrogen-containing substances mainly come from two aspects: one is that the welding shielding gas or the welding environment is humid and has a lot of moisture. These moisture decomposes into hydrogen ions during the welding process, and then forms hydrogen pores in the weld metal; the other is that the flux-cored wire material itself has a high hydrogen content, including the raw materials of the cold-rolled steel strip used in the welding wire and the core metal powder. As the main source of diffuse hydrogen in the weld, welding materials have a greater impact on the diffuse hydrogen content.

[0004] The Chinese invention patent application with publication number CN113695787A discloses a low-hydrogen anti-crack flux-cored welding wire. The invention relates to a low-hydrogen anti-crack flux-cored welding wire, comprising a low-carbon steel strip and powder, wherein the powder is composed of silicon-manganese alloy, electrolytic manganese, nickel powder, magnesia, iron alloys other than ferrotitanium, ferrotitanium, reduced iron powder, high-grade 97-degree rutile, potassium titanate, quartz sand and sodium fluoride. Its preparation method comprises the following steps: low-temperature drying of silicon-manganese alloy, electrolytic manganese, nickel powder, magnesia, iron alloys other than ferrotitanium, ferrotitanium, and reduced iron powder in the welding wire powder component, high-grade 97-degree rutile, potassium titanate, quartz sand, and sodium fluoride in the welding wire powder component, high-temperature drying, mixing the dried powders evenly, wrapping them with steel strips, and then drawing them multiple times to make finished welding wires.

[0005] The above-mentioned low-hydrogen crack-resistant flux-cored welding wire is not affected by the ambient temperature and humidity and the thickness of the base material. Under the conditions of high strength, large plate thickness and high restraint, the probability of cold and hot cracks during welding is low, and the bottom welding heat input adaptability is good, which reduces the customer's preheating and post-weld heat treatment temperature and time, and even does not require preheating and post-weld heat treatment.

[0006] However, some of the above-mentioned finished flux-cored wires are prone to many white spots on the fracture of the tensile specimens in the deposited metal test, which affects the quality of the weld. These white spots on the fracture are a form of hydrogen in the weld, indicating that hydrogen pores are still generated during the welding process of the weld deposit. The technicians in this field compared the defective flux-cored wire with the finished wire of the same batch without the white spot problem. Both are the same type of flux-cored wire products produced by the same processing production line, the same batch of metal powder filling, and the same preparation process. The samples were prepared under the same processing equipment and standards, and the welding tests were carried out under the same welding environment and methods. It can be ruled out that the diffused hydrogen causing the white spot defect on the fracture comes from the protective gas, welding environment and the core metal powder in the flux-cored wire material. The residual hydrogen content in the cold-rolled steel strip raw material used in the flux-cored wire material is low, which has little effect on the hydrogen content of the finished flux-cored wire, and is not enough to have a significant impact on the quality of the weld. Later, technicians in this field found that in the manufacturing process of flux-cored welding wire, the steel strip needs to be cleaned and dried before the forming process to remove the grease on the surface of the steel strip and ensure the cleanliness of the surface of the steel strip. The anti-rust oil contains a large amount of C and H compounds. Because it is not cleaned, it will adhere to the steel strip. During welding, diffused hydrogen can be formed and enter the weld, causing adverse effects on the weld. The higher the grease content, the higher the diffused hydrogen content of the deposited metal. Anti-rust oil not only has good anti-rust function, but also has the advantages of easy cleaning and environmental protection. Therefore, it is an indispensable material for protecting cold-rolled plates in the short term.

[0007] In summary, anti-rust oil is an indispensable part of stainless steel strip processing, and the anti-rust oil cannot be completely removed after the stainless steel strip processing is completed. During welding, the remaining anti-rust oil on the stainless steel strip is easy to form diffused hydrogen into the weld, causing hydrogen embrittlement. Summary of the invention

[0008] In order to reduce the influence of the remaining anti-rust oil on the stainless steel strip on the hydrogen embrittlement caused during welding, the present invention provides a stainless steel flux-cored welding wire and a preparation method thereof, which can effectively prevent the compounds in the anti-rust oil remaining on the surface of the welding wire during welding from easily forming diffused hydrogen that enters the weld and causes hydrogen embrittlement.

[0009] In a first aspect, the present invention provides a stainless steel flux-cored welding wire, which comprises a stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 20-25% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located on the outer layer and an alloy transition layer located on the inner layer, the fast reaction layer comprises an oil oxidizer, and the mass percentage of the oil oxidizer is 10%-12% of the total mass percentage of the double-layer flux core, and the oil oxidizer comprises high-temperature decomposition type organic matter, no The organic composition comprises a mass ratio of the high-temperature decomposition type organic matter to the inorganic composition of 1:15-20, the inorganic composition comprises copper oxide and ferric oxide in a mass ratio of 1-1.5:1, the high-temperature decomposition type organic matter comprises polytetrafluoroethylene powder and trisodium citrate in a mass ratio of 1:3-5, and the alloy transition layer comprises 316L stainless steel powder, metal powder, silicon powder, niobium carbide, and rare earth oxide, which account for 70-75%, 6-10%, 0.5-1.2%, 0.3-0.8%, and 1.5-2.5% of the total mass percentage of the double-layer core, respectively.

[0010] In the above technical scheme, the inorganic and organic substances in the outer fast reaction layer react quickly with the rust-proof oil on the surface of the stainless steel strip or the weld zone at the high temperature of the arc, avoiding the pyrolysis of the rust-proof oil surface to generate hydrogen, and at the same time forming a low-melting-point, high-fluidity slag, covering the molten pool and promoting the gas overflow in the molten pool, stabilizing the arc combustion, and reducing splashing. The copper oxide in the inorganic composition decomposes at high temperature to generate active oxygen, oxidizes the hydrocarbons in the rust-proof oil to generate gaseous carbon dioxide and water, which can overflow with the boiling of the molten pool and are insoluble in metal, avoiding hydrogen embrittlement. Ferrous oxide is used as an auxiliary oxidation to enhance the oxidation rate of high-viscosity rust-proof oil. The polytetrafluoroethylene powder in the high-temperature decomposition type organic matter decomposes at high temperature to generate CF4 and C2F4 gases, which combine with the hydrogen generated by the pyrolysis of the rust-proof oil to generate hydrogen fluoride gas phase overflow. Trisodium citrate (CH5Na3O7) carbonizes at high temperature to generate a porous carbon skeleton, adsorbs oil molecules and catalyzes their oxidation, and the sodium ions therein can stabilize the arc and reduce splashing. The fluoride (such as CaF2) decomposed from the polytetrafluoroethylene powder and the Na2O generated by trisodium citrate form sodium fluoroaluminate (Na3AlF6), which reduces the surface tension of the slag and improves the bubble dissipation.

[0011] The 316L stainless steel powder in the alloy transition layer located in the inner layer is used as the base metal to provide transition alloy elements such as chromium, nickel, and molybdenum to the weld, ensuring the crack resistance of the welding wire and improving the mechanical properties and corrosion resistance of the weld. Rare earth oxides can capture impurities such as sulfur and chlorine that are not completely removed by the fast reaction layer, further forming stable compounds, inhibiting the segregation of impurities, and preventing hydrogen embrittlement and corrosion. The metal powder may include molybdenum powder, manganese powder, and nickel powder. Molybdenum powder can enhance the acid resistance of the welding wire, manganese powder can improve the toughness of the welding wire, and nickel powder can avoid thermal cracks. Silicon powder can combine with oxygen in the molten pool to generate silicon dioxide to float, reduce the pores in the molten pool, and improve the fluidity of the slag, thereby improving the fugitive properties. Niobium carbide can refine the weld grains, improve the strength and toughness of the welding wire, and can preferentially combine with carbon to avoid the precipitation of chromium carbides. At the same time, it maintains a dispersed distribution in the welding molten pool, controls excessive grain growth, and reduces the content of diffusible hydrogen.

[0012] Optionally, the inorganic composition further comprises manganese dioxide, and the mass ratio of the copper oxide, manganese dioxide and ferric oxide is 8-9:1:4-5.

[0013] In the above technical solution, manganese dioxide can replace part of the copper oxide to react with the anti-rust oil, and at the same time can reduce the cost, but it cannot be a complete replacement.

[0014] Optionally, the high-temperature decomposition type organic matter further comprises copper phthalocyanine and sodium gluconate, and the mass ratio of the copper phthalocyanine, sodium gluconate and polytetrafluoroethylene powder is 0.2-0.5:3-5:1.

[0015] In the above technical scheme, there are many types of rust-proof oils. Some rust-proof oils can produce sulfur, chlorine and other elements by thermal decomposition. Copper phthalocyanine releases copper ions at high temperatures, catalyzing the complete oxidation of hydrocarbons in the rust-proof oil. At the same time, the generated nitrogen heterocyclic structure can adsorb sulfides in the rust-proof oil. Sodium gluconate decomposes to produce sodium carbonate and activated carbon under high temperature conditions. Sodium carbonate can react with chloride ions in the rust-proof oil to fix chlorine.

[0016] Optionally, the fast-reaction layer further comprises a fixing agent in an amount of 5-7% by weight of the total weight percentage of the double-layer drug core, and the fixing agent comprises a carbonate that can be decomposed at high temperature.

[0017] In the above technical scheme, there are many types of rust-proof oils, and some rust-proof oils also contain elements such as sulfur and chlorine. Carbonates can be decomposed into oxides and carbon dioxide under high temperature. Carbon dioxide can combine with hydrogen in the molten pool to generate gaseous water and carbon monoxide, reducing the content of diffusible hydrogen. Oxides can combine with sulfur and chlorine produced by the pyrolysis of rust-proof oil to fix sulfur and chlorine, and at the same time, they can double block the hydrogen source with copper oxide.

[0018] Optionally, the fixing agent further comprises fluoride and silicon dioxide, and the mass ratio of the fluoride, silicon dioxide and high-temperature decomposable carbonate is 1:0.3-0.5:1.5-2.

[0019] In the above technical solution, fluoride can reduce the viscosity of slag, form eutectic with silicon dioxide, promote gas escape, and combine with hydrogen to form hydrogen fluoride, reducing hydrogen diffusion. At the same time, fluoride and silicon dioxide can also form silicon fluoride (SiF4) gas to disperse oil vapor on the surface of the molten pool and inhibit hydrogen from incorporating. The fluorocarbon chain in polytetrafluoroethylene can form an oleophobic surface with fluoride to block oil penetration, while the sodium oxide decomposed by sodium gluconate can form low-melting-point sodium silicate with silicon dioxide to improve slag coverage.

[0020] Optionally, the fast-reaction layer further comprises stearate, and the mass percentage of the stearate is 0.1-0.3% of the total mass percentage of the double-layer drug core.

[0021] In the above technical solution, stearate can be used as an isolating agent to effectively isolate the inner and outer layers of drug core powder and prevent the inner and outer layers of powder from mixing.

[0022] In a second aspect, the present invention provides a method for preparing a stainless steel flux-cored welding wire, which adopts the following technical solution: A method for preparing a stainless steel flux-cored welding wire comprises the following steps: Processing of raw materials: Wipe the stainless steel strip with acetone to remove the floating oil on the surface, dry the powder of the quick reaction layer and the alloy transition layer respectively and mix them evenly; Primary U-shaped groove forming and alloy transition layer powder filling: The stainless steel strip is rolled into a primary U-shaped groove and filled with alloy transition layer mixed powder with a filling density of 4.0-4.5g / cm 3 , gently press and flatten at a pressure of 0.4-0.6MPa to form a flux core layer with a thickness of 0.12-0.15mm, and gradually press the stainless steel strip to a closed state, with a pressure of 20-25kN, and use a 1064nm, 500W fiber laser to scan along the weld to form a 0.08-0.01mm wide micro-fusion zone to obtain the first welding wire; Secondary U-shaped groove forming and quick reaction layer powder filling: The first welding wire is further rolled into a secondary U-shaped groove, and the quick reaction layer mixed powder is filled into the secondary U-shaped groove with a filling density of 3.8-4.2g / cm 3 , gently press and flatten at a pressure of 0.4-0.6MPa to form a flux core layer with a thickness of 0.06-0.10mm, gradually press the stainless steel strip to a closed state, with a pressure of 20-25kN, and use a 1064nm, 500W fiber laser to scan along the weld to form a 0.08-0.01mm wide micro-fusion zone to obtain the second welding wire; Drawing process: the second welding wire is continuously rolled and drawn through multiple diameter reduction processes to form a welding wire with a diameter of 1.2-1.6 mm, and the surface floating powder is removed by ultrasonic cleaning to obtain the stainless steel flux-cored welding wire.

[0023] Optionally, the primary U-shaped groove is rolled at an angle of 55-60°, and the secondary U-shaped groove is rolled at an angle of 85-90°.

[0024] In the above technical solution, the wide opening angle of 85-90° provides a wide filling cross section to ensure sufficient filling of the fast reaction layer powder. The narrow angle of 55-60° ensures that the fast reaction layer powder is pushed to both sides, forming an isolation channel in the center to ensure zero mixing of the alloy transition layer powder with the fast reaction layer powder during filling. At the same time, the cross-sectional shape after forming at 55-60° is closer to the final circle, reducing the amount of drawing deformation.

[0025] Optionally, the diameter reduction rate of each drawing is 5-10%, and a graphite emulsion with a concentration of 8-10% is used as a lubricant in each drawing process.

[0026] On the one hand, multiple drawing processes can gradually reduce the diameter and avoid stress concentration caused by a single large deformation, thereby improving the tensile strength and hardness of the welding wire. On the other hand, in each drawing process, defects such as pores and scratches on the surface of the welding wire can be gradually eliminated to reduce friction. On the other hand, multiple diameter reduction drawing processes combined with nano-graphite emulsion lubricants can reduce the risk of wire breakage and improve the surface smoothness of the welding wire. When using medium-concentration graphite emulsion, if the concentration is too low, insufficient lubrication will result. If the concentration is too high, the equipment may be blocked.

[0027] In the third aspect, the stainless steel flux-cored welding wire provided by the present invention and the stainless steel flux-cored welding wire prepared by the method for preparing the stainless steel flux-cored welding wire are used in the petrochemical industry, shipbuilding industry, automobile manufacturing industry, food machinery and medical equipment manufacturing industry, and energy storage and transportation equipment industry.

[0028] In summary, the present invention includes at least one of the following beneficial technical effects: The fast reaction layer is made by adding an inorganic composition. The copper oxide in the inorganic composition decomposes at high temperature to produce active oxygen, which oxidizes the hydrocarbons in the rust-proof oil to generate gaseous carbon dioxide and water, which can overflow with the boiling of the molten pool and is insoluble in metal, thus avoiding hydrogen embrittlement. Ferric oxide acts as an auxiliary oxidation to enhance the oxidation rate of high-viscosity rust-proof oil.

[0029] The rapid reaction layer is made by adding high-temperature decomposable organic matter. The polytetrafluoroethylene powder in the high-temperature decomposable organic matter decomposes at high temperature to generate CF4 and C2F4 gases, which combine with the hydrogen generated by the pyrolysis of the anti-rust oil to generate hydrogen fluoride gas and overflow. Trisodium citrate (CH5Na3O7) is carbonized at high temperature to generate a porous carbon skeleton, which adsorbs oil molecules and catalyzes their oxidation. The sodium ions therein can stabilize the arc and reduce spatter. The fluoride (such as CaF2) decomposed from the polytetrafluoroethylene powder and the Na20 generated by trisodium citrate form sodium fluoroaluminate (Na3AlF6), which reduces the surface tension of the slag and improves the bubble dissipation.

[0030] 3. By adding niobium carbide to the alloy transition layer, the weld grains can be refined, the strength and toughness of the welding wire can be improved, and niobium carbide can be preferentially combined with carbon to avoid the precipitation of chromium carbides. At the same time, it can maintain a dispersed distribution in the welding pool, control the excessive growth of grains, and reduce the content of diffusible hydrogen.

[0031] 4. By adding rare earth oxides, the alloy transition layer can capture impurities such as sulfur and chlorine that are not completely removed by the rapid reaction layer, further form stable compounds, inhibit the segregation of impurities, and prevent hydrogen embrittlement and corrosion. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below with reference to the embodiments.

[0033] The materials used in the following examples can all be purchased from the market.

[0034] Example 1: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0035] The stainless steel flux-cored welding wire comprises a stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 20% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located in the outer layer and an alloy transition layer located in the inner layer, the fast reaction layer comprises an oil oxidant, and the mass percentage of the oil oxidant is 12% of the total mass percentage of the double-layer flux core, and the oil oxidant comprises a high-temperature decomposition type organic matter, an inorganic combination The mass ratio of the high-temperature decomposable organic matter to the inorganic composition is 1:15, the inorganic composition comprises copper oxide and ferric oxide in a mass ratio of 1:1, the high-temperature decomposable organic matter comprises polytetrafluoroethylene powder and trisodium citrate in a mass ratio of 1:3, and based on the total mass percentage of the double-layer core, the alloy transition layer comprises 73.5% 316L stainless steel powder, 3% molybdenum powder, 1.2% silicon powder, 5% nickel powder, 2% manganese powder, 0.8% niobium carbide, and 2.5% rare earth oxide.

[0036] The stainless steel strip described in the embodiment of the present application is 321L stainless steel strip. In other embodiments, the stainless steel strip can also be 316L stainless steel strip, E304L stainless steel strip, etc. The niobium carbide is nano-niobium carbide, and the rare earth oxide is lanthanum oxide. In other embodiments, the rare earth oxide can also be cerium oxide, yttrium oxide, etc.

[0037] A method for preparing a stainless steel flux-cored welding wire comprises the following steps: S1. Processing of raw materials: Wipe the 321L stainless steel strip with acetone to remove the floating oil on the surface, and dry the powders of the quick reaction layer and the alloy transition layer respectively and mix them evenly; S2. Primary U-shaped groove preforming and alloy transition layer powder filling: The stainless steel strip is rolled into a primary U-shaped groove at 90° and filled with alloy transition layer mixed powder with a filling density of 4.3 g / cm 3 , gently press and flatten at a pressure of 0.5MPa to form a flux core layer with a thickness of 0.14mm, and gradually press the stainless steel strip to a closed state. The pressure is 22kN, and a 1064nm, 500W fiber laser is used to scan along the weld to form a 0.01mm wide micro-fusion zone to obtain the first welding wire; S3, secondary U-shaped groove preforming and quick reaction layer powder filling: the first welding wire is rolled into a secondary U-shaped groove at 60°, and the quick reaction layer mixed powder is filled into the secondary U-shaped groove with a filling density of 4.0g / cm 3 , gently press and flatten at a pressure of 0.5MPa to form a flux core layer with a thickness of 0.10mm, gradually press the stainless steel strip to a closed state, with a pressure of 20-25kN, and use a 1064nm, 500W fiber laser to scan along the weld to form a 0.08-0.01mm wide micro-fusion zone to obtain the second welding wire; S4, drawing process: the second welding wire is further rolled and drawn through multiple diameter reductions to form a welding wire with a diameter of 1.2-1.6 mm, and the surface floating powder is removed by ultrasonic cleaning to obtain a stainless steel flux-cored welding wire 1#.

[0038] Example 2: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0039] The stainless steel flux-cored welding wire comprises an E304L stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the E304L stainless steel strip, and the filling amount of the double-layer flux core is 25% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located on the outer layer and an alloy transition layer located on the inner layer, the fast reaction layer comprises an oil oxidizer, the mass percentage of the oil oxidizer is 12% of the total mass percentage of the double-layer flux core, and the oil oxidizer comprises a high-temperature decomposition type The high-temperature decomposable organic matter and the inorganic composition have a mass ratio of 1:20, the inorganic composition comprises copper oxide and ferric oxide in a mass ratio of 1.5:1, the high-temperature decomposable organic matter comprises polytetrafluoroethylene powder and trisodium citrate in a mass ratio of 1:5, and the alloy transition layer comprises 75% 316L stainless steel powder, 2.5% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% manganese powder, 0.5% nano-niobium carbide, and 2% cerium oxide in terms of the total mass percentage of the double-layer core.

[0040] The preparation method of the stainless steel flux-cored welding wire is the same as that of Example 1.

[0041] Example 3: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0042] The stainless steel flux-cored welding wire comprises a 316L stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 22% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located in the outer layer and an alloy transition layer located in the inner layer, the fast reaction layer comprises an oil oxidizer, and the mass percentage of the oil oxidizer is 11.5% of the total mass percentage of the double-layer flux core, and the oil oxidizer comprises a high-temperature decomposition type organic The mass ratio of the high-temperature decomposable organic matter to the inorganic composition is 1:18, the inorganic composition comprises copper oxide and ferric oxide in a mass ratio of 1.5:1, the high-temperature decomposable organic matter comprises polytetrafluoroethylene powder and trisodium citrate in a mass ratio of 1:4, and the alloy transition layer comprises 75% 316L stainless steel powder, 3% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% manganese powder, 0.5% nano-niobium carbide, and 2% lanthanum oxide, calculated by the total mass percentage of the double-layer core.

[0043] The preparation method of the stainless steel flux-cored welding wire is the same as that of Example 1.

[0044] Example 4: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0045] The stainless steel flux-cored welding wire comprises a 316L stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 22% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located on the outer layer and an alloy transition layer located on the inner layer, the fast reaction layer comprises an oil oxidant, and the mass percentage of the oil oxidant is 11.5% of the total mass percentage of the double-layer flux core, and the oil oxidant comprises high-temperature decomposition type organic matter, The inorganic composition comprises a mass ratio of the pyrolytic organic matter to the inorganic composition of 1:18, the inorganic composition comprises copper oxide, manganese dioxide and ferric oxide in a mass ratio of 8:1:4, the pyrolytic organic matter comprises polytetrafluoroethylene powder and trisodium citrate in a mass ratio of 1:4, and the alloy transition layer comprises 75% 316L stainless steel powder, 3% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% manganese powder, 0.5% nano-niobium carbide and 2% lanthanum oxide, based on the total mass percentage of the double-layer core.

[0046] The preparation method of the stainless steel flux-cored welding wire is the same as that of Example 1.

[0047] Example 5: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0048] The stainless steel flux-cored welding wire comprises a ‌316L stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 22% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located in the outer layer and an alloy transition layer located in the inner layer, the fast reaction layer comprises an oil oxidant, the mass percentage of the oil oxidant is 11.5% of the total mass percentage of the double-layer flux core, and the oil oxidant comprises a high-temperature decomposition type organic matter and an inorganic composition, The mass ratio of the high-temperature decomposable organic matter to the inorganic composition is 1:18, the inorganic composition includes copper oxide and ferric oxide in a mass ratio of 1.5:1, the high-temperature decomposable organic matter includes polytetrafluoroethylene powder, trisodium citrate, copper phthalocyanine and sodium gluconate in a mass ratio of 1:4:0.3:4, and the alloy transition layer includes 75% 316L stainless steel powder, 3% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% manganese powder, 0.5% nano-niobium carbide, and 2% lanthanum oxide, calculated by the total mass percentage of the double-layer core.

[0049] Example 6: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0050] The stainless steel flux-cored welding wire comprises a ‌316L stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 22% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located on the outer layer and an alloy transition layer located on the inner layer, the fast reaction layer comprises an oil oxidant, and the mass percentage of the oil oxidant is 11.5% of the total mass percentage of the double-layer flux core, the oil oxidant comprises a high-temperature decomposition type organic matter, an inorganic composition, and the The mass ratio of the high-temperature decomposable organic matter to the inorganic composition is 1:18, the inorganic composition includes copper oxide, manganese dioxide, and ferric oxide in a mass ratio of 8:1:4, the high-temperature decomposable organic matter includes polytetrafluoroethylene powder, trisodium citrate, copper phthalocyanine, and sodium gluconate in a mass ratio of 1:4:0.3:4, and the alloy transition layer includes 75% 316L stainless steel powder, 3% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% manganese powder, 0.5% nano-niobium carbide, and 2% lanthanum oxide, calculated by the total mass percentage of the double-layer core.

[0051] The preparation method of the stainless steel flux-cored welding wire is the same as that of Example 1.

[0052] Example 7: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0053] The stainless steel flux-cored welding wire comprises a ‌316L stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 22% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located on the outer layer and an alloy transition layer located on the inner layer, and based on the total mass percentage of the double-layer flux core, the fast reaction layer comprises 10% of an oil oxidant and 5% of a fixing agent, the oil oxidant comprises a high-temperature decomposable organic substance and an inorganic composition, and the high-temperature decomposable organic substance The mass ratio of the inorganic composition is 1:18, the inorganic composition is copper oxide and ferric oxide in a mass ratio of 1.5:1, the high-temperature decomposable organic matter includes polytetrafluoroethylene powder and trisodium citrate in a mass ratio of 1:4, the fixing agent includes calcium carbonate, and in other embodiments, the high-temperature decomposable carbonate can also be selected from barium carbonate, magnesium carbonate, etc., the alloy transition layer includes 71.5% 316L stainless steel powder, 3% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% manganese powder, 0.5% nano-niobium carbide, and 2% lanthanum oxide.

[0054] The preparation method of the stainless steel flux-cored welding wire is the same as that of Example 1.

[0055] Example 8: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0056] The stainless steel flux-cored welding wire comprises a ‌316L stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 22% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located on the outer layer and an alloy transition layer located on the inner layer, and the fast reaction layer comprises 10% of an oil oxidant and 5% of calcium carbonate, the oil oxidant comprises a high-temperature decomposition type organic matter and an inorganic composition, and the high The mass ratio of the high-temperature decomposition type organic matter to the inorganic composition is 1:18, the inorganic composition is copper oxide and ferric oxide in a mass ratio of 1.5:1, the high-temperature decomposition type organic matter includes polytetrafluoroethylene powder, trisodium citrate, copper phthalocyanine and sodium gluconate in a mass ratio of 1:4:0.3:4, and the alloy transition layer includes 71.5% 316L stainless steel powder, 3% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% manganese powder, 0.5% nano-niobium carbide, and 2% lanthanum oxide, calculated by the total mass percentage of the double-layer core.

[0057] The preparation method of the stainless steel flux-cored welding wire is the same as that of Example 1.

[0058] Example 9: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0059] The stainless steel flux-cored welding wire comprises a 316L stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 22% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located on the outer layer and an alloy transition layer located on the inner layer, and the fast reaction layer comprises 10% of an oil oxidizer and 5% of a curing agent as a percentage of the total mass of the double-layer flux core, and the fixing agent comprises fluoride, silicon dioxide, and calcium carbonate in a mass ratio of 1:0.4:1.5, wherein calcium fluoride is selected as the fluoride, and in other embodiments, fluoride is selected as calcium fluoride. Potassium fluoride and lithium fluoride can also be selected from the compounds. The oil oxidant includes high-temperature decomposable organic matter and an inorganic composition. The mass ratio of the high-temperature decomposable organic matter to the inorganic composition is 1:18. The inorganic composition is copper oxide and ferric oxide in a mass ratio of 1.5:1. The high-temperature decomposable organic matter includes polytetrafluoroethylene powder and trisodium citrate in a mass ratio of 1:4. Calculated by the total mass percentage of the double-layer core, the alloy transition layer includes 71.5% 316L stainless steel powder, 3% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% manganese powder, 0.5% nano-niobium carbide, and 2% lanthanum oxide.

[0060] The preparation method of the stainless steel flux-cored welding wire is the same as that of Example 1.

[0061] Example 10: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0062] The stainless steel flux-cored welding wire comprises a 316L stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 22% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located in the outer layer and an alloy transition layer located in the inner layer, and based on the total mass percentage of the double-layer flux core, the fast reaction layer comprises 10% of an oil oxidant and 5% of a curing agent, the fixing agent comprises calcium fluoride, silicon dioxide, and calcium carbonate in a mass ratio of 1:0.4:1.5, and the oil oxidant comprises high The high-temperature decomposable organic matter and the inorganic composition, the mass ratio of the high-temperature decomposable organic matter to the inorganic composition is 1:18, the inorganic composition is copper oxide and ferric oxide in a mass ratio of 1.5:1, the high-temperature decomposable organic matter comprises polytetrafluoroethylene powder, trisodium citrate, copper phthalocyanine and sodium gluconate in a mass ratio of 1:4:0.3:4, and the alloy transition layer comprises 71.5% 316L stainless steel powder, 3% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% manganese powder, 0.5% nano-niobium carbide and 2% lanthanum oxide in terms of the total mass percentage of the double-layer core.

[0063] The preparation method of the stainless steel flux-cored welding wire is the same as that of Example 1.

[0064] Example 11: This example discloses a stainless steel flux-cored welding wire and a method for preparing the same.

[0065] The stainless steel flux-cored welding wire comprises a 316L stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 22% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located in the outer layer and an alloy transition layer located in the inner layer, and the fast reaction layer comprises 10% of an oil oxidant, 5% of a curing agent, and 0.2% of a stearate in terms of the total mass percentage of the double-layer flux core. In this embodiment, the stearate is selected from calcium stearate, and in other embodiments, the stearate can also be selected from sodium stearate, zinc stearate, etc., and the fixing agent comprises a mass ratio of 1:0.4: 1.5 of calcium fluoride, silicon dioxide, and calcium carbonate, the oil oxidant includes high-temperature decomposable organic matter and an inorganic composition, the mass ratio of the high-temperature decomposable organic matter to the inorganic composition is 1:18, the inorganic composition is copper oxide and ferric oxide in a mass ratio of 1.5:1, the high-temperature decomposable organic matter includes polytetrafluoroethylene powder, trisodium citrate, copper phthalocyanine and sodium gluconate in a mass ratio of 1:4:0.3:4, and calculated by the total mass percentage of the double-layer core, the alloy transition layer includes 71.3% 316L stainless steel powder, 3% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% manganese powder, 0.5% nano-niobium carbide, and 2% lanthanum oxide.

[0066] The preparation method of the stainless steel flux-cored welding wire is the same as that of Example 1.

[0067] Comparative Example 1: This comparative example provides a comparative stainless steel flux-cored welding wire D1, which comprises a 316L stainless steel strip and a single-layer flux core, wherein the single-layer flux core is filled in the stainless steel strip, and the filling amount of the single-layer flux core is 22% of the total mass of the stainless steel flux-cored welding wire; based on the total mass percentage of the single-layer flux core, the single-layer flux core comprises 10% oil oxidizer, 5% curing agent, 0.2% calcium stearate, 71.3% 316L stainless steel powder, 3% molybdenum powder, 1% silicon powder, 5% nickel powder, 2% Manganese powder, 0.5% nano-niobium carbide, 2% lanthanum oxide, the fixing agent includes calcium fluoride, silicon dioxide, and calcium carbonate in a mass ratio of 1:0.4:1.5, the oil oxidant includes high-temperature decomposable organic matter and an inorganic composition, the mass ratio of the high-temperature decomposable organic matter to the inorganic composition is 1:18, the inorganic composition is copper oxide and ferric oxide in a mass ratio of 1.5:1, and the high-temperature decomposable organic matter includes polytetrafluoroethylene powder, trisodium citrate, copper phthalocyanine and sodium gluconate in a mass ratio of 1:4:0.3:4.

[0068] A method for preparing a comparative stainless steel flux-cored welding wire D1 comprises the following steps: S1. Processing of raw materials: Wipe the 321L stainless steel strip with acetone to remove the floating oil on the surface, and dry the above powders separately and mix them evenly; S2. U-shaped groove preforming and powder filling: The stainless steel strip is rolled into a U-shaped groove at 90° and filled with mixed powder with a filling density of 4.3g / cm 3 , gently press and flatten at a pressure of 0.5MPa to form a flux core layer with a thickness of 0.2mm, and gradually press the stainless steel strip to a closed state. The pressure is 22kN, and a 1064nm, 500W fiber laser is used to scan along the weld to form a 0.01mm wide micro-fusion zone to obtain the first welding wire; S3, drawing process: the first welding wire is further rolled and drawn through multiple diameter reduction processes to form a welding wire with a diameter of 1.2-1.6 mm, and the surface floating powder is removed by ultrasonic cleaning to obtain a comparative stainless steel flux-cored welding wire D1.

[0069] Comparative Example 2: This comparative example provides a comparative stainless steel flux-cored welding wire D2, which has the same components as the stainless steel flux-cored welding wire of Example 11, except that the oil oxidant does not include high-temperature decomposition organic matter. Its preparation method is the same as that of Example 1.

[0070] Comparative Example 3: This comparative example provides a comparative stainless steel flux-cored welding wire D3, which has the same components as the stainless steel flux-cored welding wire of Example 11, except that the oil oxidant does not include an inorganic composition. The preparation method thereof is the same as that of Example 1.

[0071] Comparative Example 4: This comparative example provides a comparative stainless steel flux-cored welding wire D4, which has the same components as the stainless steel flux-cored welding wire of Example 11, except that the alloy transition layer does not include niobium carbide. The preparation method thereof is the same as that of Example 1.

[0072] Comparative Example 5: This comparative example provides a comparative stainless steel flux-cored welding wire D5, which has the same components as the stainless steel flux-cored welding wire of Example 11, except that the alloy transition layer does not include rare earth oxides. The preparation method thereof is the same as that of Example 1.

[0073] Comparative Example 6: This comparative example provides a comparative stainless steel flux-cored welding wire D6, which has the same components as the stainless steel flux-cored welding wire of Example 11, except that the inorganic composition only includes ferric oxide. The preparation method thereof is the same as that of Example 1.

[0074] Comparative Example 7: This comparative example provides a comparative stainless steel flux-cored welding wire D7, which has the same components as the stainless steel flux-cored welding wire of Example 11, except that zinc oxide is used instead of copper oxide. The preparation method is the same as that of Example 1.

[0075] Comparative Example 8: This comparative example provides a comparative stainless steel flux-cored welding wire D8, which has the same components as the stainless steel flux-cored welding wire of Example 11, except that polybenzimidazole, an organic substance that does not decompose at high temperatures, is used instead of polytetrafluoroethylene micropowder and trisodium citrate, an organic substance that decomposes at high temperatures. The preparation method is the same as that of Example 1.

[0076] Comparative Example 9: This comparative example provides a comparative stainless steel flux-cored welding wire D9, which has the same components as the stainless steel flux-cored welding wire of Example 11, except that titanium oxide is used instead of rare earth oxide. The preparation method is the same as that of Example 1.

[0077] The stainless steel flux-cored welding wires #1-#11 of Examples 1-11 and the comparative stainless steel flux-cored welding wires D1-D9 of Comparative Examples 1-9 were subjected to various welding tests as shown in Table 1. The welding performance is shown in Table 2, including porosity test, arc stability test, welding spatter test, diffusible hydrogen test (mercury method), tensile strength test, groove welding experimental crack test, corrosion resistance test, and surface oil stain test (water drip diffusion method).

[0078] Table 1 Voltage (V) Current (A) Welding speed (cm / min) Dry extension length (mm) Welding time (h) Welding wind speed (m / s) Relative humidity (%) 29 250 10 20 3 ≤2 ≤90 Table 2 Example Performance Diffusible hydrogen content (mL / 100g) Weld porosity (%) Groove welding test cracks (%) Tensile strength (MPa) Corrosion resistance Arc stability Spatter rate (%) Water drop shape Example 1 2.29 1.28 2.14 620 excellent excellent 3.4 Round Example 2 2.30 1.25 2.13 623 excellent excellent 3.3 Round Example 3 2.22 1.21 2.08 631 excellent excellent 3.1 Round Example 4 2.25 1.21 2.09 635 excellent excellent 3.1 Round Example 5 2.17 1.19 2.01 638 excellent excellent 3.1 Round Example 6 2.19 1.20 2.02 640 excellent excellent 3.0 Round Example 7 2.15 1.16 1.95 642 excellent excellent 2.9 Round Example 8 2.10 1.12 1.87 645 excellent excellent 2.8 Round Example 9 2.10 1.13 1.90 645 excellent excellent 2.8 Round Example 10 2.06 1.10 1.82 648 excellent excellent 2.6 Round Embodiment 11 2.05 1.09 1.77 651 excellent excellent 2.5 Round Comparative Example 1 3.35 3.45 3.27 610 good good 4.5 Beaded Comparative Example 2 3.24 3.33 3.19 641 excellent excellent 3.8 Beaded Comparative Example 3 3.40 3.56 3.32 595 good good 4.3 Beaded Comparative Example 4 2.59 2.43 2.51 623 excellent excellent 3.2 Beaded Comparative Example 5 2.71 2.79 2.60 633 excellent excellent 3.5 Beaded Comparative Example 6 3.19 2.85 2.87 647 excellent excellent 3.6 Beaded Comparative Example 7 3.21 2.91 2.92 645 excellent excellent 3.7 Beaded Comparative Example 8 3.20 2.89 2.90 642 excellent excellent 3.8 Beaded Comparative Example 9 2.48 2.37 2.28 649 excellent excellent 3.1 Beaded It can be seen from the data of Examples 1-3, especially the data of Example 3, that through the reasonable ratio of the constituent materials of the stainless steel double-layer flux-cored welding wire, the stainless steel flux-cored welding wire of the present application has a low diffusible hydrogen content, a small weld porosity, and a small crack, and the tensile strength, corrosion resistance, arc stability, and spatter rate are all excellent. At the same time, the water droplets diffuse into a round shape, indicating that there is no oil stain on the surface, which effectively avoids the compounds in the rust-proof oil remaining on the surface of the welding wire during welding to form diffused hydrogen that enters the weld and causes hydrogen embrittlement.

[0079] Compared with Example 3 and Example 4, and Example 5 and Example 6, the components of the inorganic composition are slightly different, but the properties of the obtained stainless steel flux-cored welding wire are not much different, so manganese dioxide can replace part of copper oxide to participate in the reaction.

[0080] Compared with Example 3 and Examples 7 and 8, Example 5 has different components of high-temperature decomposition-type organic matter, and the various properties of the obtained stainless steel flux-cored welding wire are relatively excellent, which shows that copper phthalocyanine releases copper ions at high temperatures, catalyzes the complete oxidation of hydrocarbons in the rust-proof oil, and the generated nitrogen heterocyclic structure can adsorb sulfides in the rust-proof oil. Sodium gluconate decomposes to generate sodium carbonate and activated carbon under high temperature conditions, and sodium carbonate can react with chloride ions in the rust-proof oil to fix chlorine.

[0081] Compared with Example 3, Example 7 adds carbonate, and the performance of the obtained stainless steel flux-cored welding wire is better than that of Example 3. This shows that carbonate can be decomposed into oxides and carbon dioxide under high temperature, and carbon dioxide can combine with hydrogen in the molten pool to generate gaseous water and carbon monoxide, thereby reducing the content of diffusible hydrogen. The oxide can combine with sulfur and chlorine produced by the pyrolysis of rust-proof oil to fix sulfur and chlorine, and can also double block the hydrogen source with copper oxide.

[0082] Compared with Example 7 and Example 10 and Example 8, fluoride and silicon dioxide are added to the curing agent in Example 9. The performance of the stainless steel flux-cored welding wire obtained in Example 9 is better than that in Example 7, and the performance of the stainless steel flux-cored welding wire obtained in Example 10 is better than that in Example 8. This shows that fluoride can form a eutectic with silicon dioxide to promote gas escape, and combine with hydrogen to generate hydrogen fluoride, reducing hydrogen diffusion. At the same time, fluoride and silicon dioxide can also form silicon fluoride (SiF4) gas to disperse oil vapor on the surface of the molten pool and inhibit hydrogen integration.

[0083] Compared with Example 10, in Example 11, stearate is added as an isolation agent to effectively isolate the inner and outer layers of the drug core powder and prevent the inner and outer layers of powder from mixing.

[0084] Compared with Examples 1-11, Comparative Example 1 adopts a single-layer flux core design, and the obtained stainless steel flux cored welding wire D1 performs worse than the stainless steel flux cored welding wires #1-#11 obtained in Examples 1-11 in all performances, indicating that the double-layer flux core design of the present application avoids, to a certain extent, the compounds in the rust-proof oil remaining on the surface of the welding wire during welding to form diffused hydrogen that enters the weld and causes hydrogen embrittlement.

[0085] Compared with Comparative Examples 2-9, in Example 11, the oil oxidant in Comparative Example 2 does not include high-temperature decomposition organic matter; the oil oxidant in Comparative Example 3 does not include an inorganic composition; the alloy transition layer in Comparative Example 4 does not include niobium carbide; the alloy transition layer in Comparative Example 5 does not include rare earth oxides; the inorganic composition in Comparative Example 6 only includes ferric oxide; zinc oxide is used instead of copper oxide in Comparative Example 7; polybenzimidazole, a high-temperature non-decomposable organic matter, is used instead of polytetrafluoroethylene micropowder and trisodium citrate, a high-temperature decomposable organic matter, in Comparative Example 8; titanium oxide is used instead of rare earth oxides in Comparative Example 9. The various properties of the obtained comparative stainless steel flux-cored welding wire are far lower than those of the stainless steel flux-cored welding wire in Example 11, and the water droplets are all in the shape of beads, indicating that the surface of the comparative stainless steel flux-cored welding wire may still have anti-rust oil that has not reacted completely. It can be seen from this that the missing or replaced materials cannot play a role in the stainless steel flux-cored welding wire, but will reduce the role of the stainless steel flux-cored welding wire, so each component cannot be arbitrarily replaced by other materials.

[0086] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A stainless steel flux-cored welding wire, characterized in that: The stainless steel flux-cored welding wire comprises a stainless steel strip and a double-layer flux core, wherein the double-layer flux core is filled in the stainless steel strip, and the filling amount of the double-layer flux core is 20-25% of the total mass of the stainless steel flux-cored welding wire; the double-layer flux core comprises a fast reaction layer located in the outer layer and an alloy transition layer located in the inner layer, the fast reaction layer comprises an oil oxidant, and the mass percentage of the oil oxidant is 10%-12% of the total mass percentage of the double-layer flux core, the oil oxidant comprises a high-temperature decomposition type organic matter, an inorganic composition, and the high-temperature decomposition type organic matter is 10%-12% of the total mass percentage of the double-layer flux core. The mass ratio of the decomposable organic matter to the inorganic composition is 1:15-20, the inorganic composition comprises copper oxide and ferric oxide in a mass ratio of 1-1.5:1, the high-temperature decomposable organic matter comprises polytetrafluoroethylene powder and trisodium citrate in a mass ratio of 1:3-5, and the alloy transition layer comprises 316L stainless steel powder, metal powder, silicon powder, niobium carbide, and rare earth oxide, which account for 70-75%, 6-10%, 0.5-1.2%, 0.3-0.8%, and 1.5-2.5% of the total mass percentage of the double-layer core, respectively.

2. A stainless steel flux-cored welding wire according to claim 1, characterized in that: The inorganic composition also includes manganese dioxide, and the mass ratio of the copper oxide, manganese dioxide and ferric oxide is 8-9:1:4-5.

3. A stainless steel flux-cored welding wire according to claim 1, characterized in that: The high temperature decomposition type organic matter also includes copper phthalocyanine and sodium gluconate, and the mass ratio of the copper phthalocyanine, sodium gluconate and polytetrafluoroethylene powder is 0.2-0.5:3-5:

1.

4. A stainless steel flux-cored welding wire according to claim 1, characterized in that: The fast-reaction layer further comprises a fixing agent in an amount of 5-7% of the total mass percentage of the double-layer drug core, and the fixing agent comprises a carbonate that can be decomposed at high temperature.

5. A stainless steel flux-cored welding wire according to claim 4, characterized in that: The fixing agent also includes fluoride and silicon dioxide, and the mass ratio of the fluoride, silicon dioxide and high-temperature decomposable carbonate is 1:0.3-0.5:1.5-2.

6. A stainless steel flux-cored welding wire according to any one of claims 1 to 5, characterized in that: The fast-reaction layer further comprises stearate, and the mass percentage of the stearate is 0.1-0.3% of the total mass percentage of the double-layer drug core.

7. A method for preparing a stainless steel flux-cored welding wire using any one of claims 1 to 6, characterized in that: The following steps are involved: Processing of raw materials: Wipe the stainless steel strip with acetone to remove the floating oil on the surface, dry the powder of the quick reaction layer and the alloy transition layer respectively and mix them evenly; Primary U-shaped groove forming and alloy transition layer powder filling: The stainless steel strip is rolled into a primary U-shaped groove and filled with alloy transition layer mixed powder with a filling density of 4.0-4.5g / cm 3 , gently press and flatten at a pressure of 0.4-0.6MPa to form a flux core layer with a thickness of 0.12-0.15mm, and gradually press the stainless steel strip to a closed state, with a pressure of 20-25kN, and use a 1064nm, 500W fiber laser to scan along the weld to form a 0.08-0.01mm wide micro-fusion zone to obtain the first welding wire; Secondary U-shaped groove forming and quick reaction layer powder filling: The first welding wire is further rolled into a secondary U-shaped groove, and the quick reaction layer mixed powder is filled into the secondary U-shaped groove with a filling density of 3.8-4.2g / cm 3 , gently press and flatten at a pressure of 0.4-0.6MPa to form a flux core layer with a thickness of 0.06-0.10mm, gradually press the stainless steel strip to a closed state, with a pressure of 20-25kN, and use a 1064nm, 500W fiber laser to scan along the weld to form a 0.08-0.01mm wide micro-fusion zone to obtain the second welding wire; Drawing process: the second welding wire is continuously rolled and drawn through multiple diameter reduction processes to form a welding wire with a diameter of 1.2-1.6 mm, and the surface floating powder is removed by ultrasonic cleaning to obtain the stainless steel flux-cored welding wire.

8. The method for preparing a stainless steel flux-cored welding wire according to claim 7, characterized in that: The primary U-shaped groove is rolled at an angle of 85-90°, and the secondary U-shaped groove is rolled at an angle of 55-60°.

9. The method for preparing a stainless steel flux-cored welding wire according to claim 7, characterized in that: The diameter reduction rate of each drawing is 5-10%, and a graphite emulsion with a concentration of 8-10% is used as a lubricant in each drawing process.

10. Application of a stainless steel flux-cored welding wire in the petrochemical industry, shipbuilding industry, automobile manufacturing industry, food machinery and medical equipment manufacturing industry, and energy storage and transportation equipment industry, characterized in that: A stainless steel flux-cored welding wire prepared using the stainless steel flux-cored welding wire as described in any one of claims 1 to 6, or the method for preparing a stainless steel flux-cored welding wire as described in any one of claims 7 to 9.