A stainless steel flux-cored wire and its preparation method

Abstract

The present 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, 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 wire; the double-layer flux core comprises a rapid reaction layer and an alloy transition layer, the rapid reaction layer comprises an oil stain oxidant, the oil stain oxidant comprises a high-temperature decomposition type organic substance and an inorganic composition, the inorganic composition comprises copper oxide and ferric oxide with a mass ratio of 1-1.5:1, the high-temperature decomposition type organic substance comprises polytetrafluoroethylene fine powder and trisodium citrate with 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. The present invention can effectively avoid that compounds in the rust preventive oil remaining on the surface of the wire during welding are liable to form diffusible hydrogen and enter the weld seam to cause hydrogen embrittlement.

Description

Technical Field

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

[0002] As the fourth-generation welding material, flux-cored wires have the advantages of strong adaptability, easy alloy addition, high deposition rate, good process performance and mechanical properties, high productivity, and low cost, and are widely used in shipbuilding, offshore engineering, bridges, construction machinery, petrochemical industry, energy equipment, pressure vessels and other fields. Flux-cored wires are mainly composed of steel strips wrapping powder materials, and are formed by rolling through a rolling mill and drawing through a wire drawing machine.

[0003] Hydrogen pores are a kind of fine crack defects in the weld seam, which can generate huge stresses. During the welding process of workpieces, under the intertwined action of the internal stress and external stress in the hydrogen pores, cracks gradually expand, and "hydrogen embrittlement" is likely to occur, thus affecting the quality of the welded workpieces. The sources of diffusible hydrogen in the weld seam are extensive. 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 with a large amount of moisture, and these moisture decomposes into hydrogen ions during the welding process, and then hydrogen pores are formed in the weld metal; the other is that the hydrogen content brought in by the flux-cored wire material itself is relatively high, including the raw material of the cold-rolled steel strip used for the wire and the core metal powder. As the main source of diffusible hydrogen in the weld seam, welding materials have a great influence on the content of diffusible hydrogen.

[0004] The Chinese patent application with the publication number of CN113695787A discloses a low-hydrogen crack-resistant flux-cored wire. The invention relates to a low-hydrogen crack-resistant flux-cored wire, which includes a low-carbon steel strip and powder. The powder is composed of ferrosilicon manganese alloy, electrolytic manganese, nickel powder, magnesia, ferroalloy other than ferrotitanium, ferrotitanium, reduced iron powder, high-grade 97-degree rutile, potassium titanate, quartz sand, and sodium fluoride. The preparation method includes the following steps: performing low-temperature drying on the ferrosilicon manganese alloy, electrolytic manganese, nickel powder, magnesia, ferroalloy other than ferrotitanium, ferrotitanium, and reduced iron powder in the wire powder components, performing high-temperature drying on the high-grade 97-degree rutile, potassium titanate, quartz sand, and sodium fluoride in the wire powder components, mixing the dried powder evenly, wrapping it with a steel strip, and then performing multiple draws to make a finished wire.

[0005] The above-mentioned low-hydrogen crack-resistant flux-cored 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, the adaptability of the heat input at the bottom welding is good, the preheating and post-weld heat treatment temperature and time of the customer are reduced, and even preheating and post-weld heat treatment are not required.

[0006] However, in the tensile test specimens of some of the above-mentioned flux-cored wire products, there are still many white spots easily appearing on the fracture surface, which affects the weld quality. These white spots on the fracture surface are a form of hydrogen existence in the weld, indicating that hydrogen pores are still generated in the weld metal during welding. Those skilled in the art compared the defective flux-cored wire with the wire products of the same batch that did not have the white spot problem. The two are the same type of flux-cored wire products produced by the same processing production line, filled with the same batch of metal powder, and prepared by the same preparation process. They are sampled under the same processing equipment and standards, and welding tests are carried out under the same welding environment and methods. It can be excluded that the diffusible hydrogen causing the white spot defect on the fracture surface comes from the shielding gas, the 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 relatively low, and has a very small impact on the hydrogen content of the flux-cored wire product, which is not enough to have an obvious impact on the weld quality. Subsequently, those skilled in the art found that during the manufacturing process of the flux-cored wire, the steel strip needs to be cleaned and dried before the forming process to remove the grease on the steel strip surface and ensure the cleanliness of the steel strip surface. The rust preventive oil contains a large amount of C and H compounds. Because it is not cleaned thoroughly, it will adhere to the steel strip and can form diffusible hydrogen during welding and enter the weld, causing adverse effects on the weld. The higher the grease content, the higher the diffusible hydrogen content in the weld metal. Moreover, the rust preventive oil not only has good rust prevention 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, the rust preventive oil is an essential part of the stainless steel strip processing. After the stainless steel strip processing is completed, the rust preventive oil cannot be completely removed. During welding, the remaining rust preventive oil on the stainless steel strip is likely to form diffusible hydrogen and enter the weld, causing hydrogen embrittlement. Summary of the Invention

[0008] In order to reduce the influence of the remaining rust preventive oil on the stainless steel strip on the hydrogen embrittlement phenomenon during welding, the present invention provides a stainless steel flux-cored wire and its preparation method, which can effectively avoid the compounds in the rust preventive oil remaining on the surface of the wire during welding from easily forming diffusible hydrogen and entering the weld to cause hydrogen embrittlement.

[0009] In a first aspect, the present invention provides a stainless steel flux-cored wire, which includes a stainless steel strip and a double-layered flux core. Among them, the double-layered flux core is filled in the stainless steel strip, and the filling amount of the double-layered flux core is 20-25% of the total mass of the stainless steel flux-cored wire; the double-layered flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. The rapid reaction layer includes an oil stain oxidant, and the mass percentage of the oil stain oxidant is 10%-12% of the total mass percentage of the double-layered flux core. The oil stain oxidant includes a high-temperature decomposition type organic matter and an inorganic composition, and the mass ratio of the high-temperature decomposition type organic matter to the inorganic composition is 1:15-20. The inorganic composition includes copper oxide and ferric oxide with a mass ratio of 1-1.5:1. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder and trisodium citrate with a mass ratio of 1:3-5. The alloy transition layer includes 316L stainless steel powder, metal powder, silicon powder, niobium carbide, and rare earth oxide, which are 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-layered flux core respectively.

[0010] In the above technical solution, the inorganic substances and organic substances in the rapid reaction layer on the outer layer rapidly react with the rust preventive oil on the surface of the stainless steel strip or the weld zone under the high temperature of the electric arc, avoiding the thermal decomposition of the rust preventive oil surface to generate hydrogen. At the same time, a slag with low melting point and high fluidity is formed, covering the molten pool and promoting the overflow of gas in the molten pool, stabilizing the electric arc combustion and reducing spatter. Copper oxide in the inorganic composition decomposes at high temperature to generate active oxygen, oxidizing hydrocarbons in the rust preventive oil to generate gaseous carbon dioxide and water, which can overflow with the boiling of the molten pool and are insoluble in the metal, avoiding hydrogen embrittlement. Ferric oxide acts as an auxiliary oxidant to enhance the oxidation rate of high-viscosity rust preventive oil. Polytetrafluoroethylene micropowder in the high-temperature decomposition type organic matter decomposes at high temperature to generate CF 4 and C 2 F 4 gas, which combines with the hydrogen generated by the thermal decomposition of the rust preventive oil to generate hydrogen fluoride and overflows in the gas phase. Trisodium citrate (CH 5 Na 3 O 7 ) is carbonized at high temperature to form a porous carbon skeleton, adsorbing oil stain molecules and catalyzing their oxidation. The sodium ions therein can stabilize the electric arc and reduce spatter. Fluorides decomposed from polytetrafluoroethylene powder (such as CaF 2 ) and Na 2 O generated by trisodium citrate form sodium hexafluoroaluminate (Na 3 AlF 6 ), reducing the surface tension of the slag and improving the bubble dissipation property.

[0011] The 316L stainless steel powder in the alloy transition layer located in the inner layer serves as the base metal, which can provide transition alloying elements such as chromium, nickel, and molybdenum to the weld seam, ensuring the crack resistance of the welding wire and enhancing the mechanical properties and corrosion resistance of the weld seam. Rare earth oxides 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. The metal powder can 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 hot cracks. Silicon powder can combine with oxygen in the molten pool to form silicon dioxide and float up, reducing the porosity of the molten pool. It can also improve the fluidity of the slag, thereby enhancing the fugacity. Niobium carbide can refine the weld seam grains, improve the strength and toughness of the welding wire, preferentially combine with carbon to avoid the precipitation of chromium carbides, and at the same time maintain a dispersed distribution in the welding molten pool, control the excessive growth of grains, and reduce the content of diffusible hydrogen.

[0012] Optionally, the inorganic composition further includes manganese dioxide, and the mass ratio of copper oxide, manganese dioxide, and iron(III) oxide is 8 - 9:1:4 - 5.

[0013] In the above technical solution, manganese dioxide can react with the rust preventive oil instead of part of the copper oxide, and at the same time can reduce the cost, but it cannot completely replace it.

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

[0015] In the above technical solution, there are various types of rust preventive oils. Some rust preventive oils can produce elements such as sulfur and chlorine during pyrolysis. Copper phthalocyanine releases copper ions at high temperatures, catalyzes the complete oxidation of hydrocarbons in the rust preventive oil, and at the same time the generated nitrogen heterocyclic structure can adsorb sulfides in the rust preventive oil. Sodium gluconate decomposes into sodium carbonate and activated carbon under high-temperature conditions. Sodium carbonate can react with chloride ions in the rust preventive oil to play a role in fixing chlorine.

[0016] Optionally, the rapid reaction layer further includes a fixing agent accounting for 5 - 7% of the total mass of the double-layer flux cored wire, and the fixing agent includes carbonate that can be decomposed at high temperature.

[0017] In the above technical solution, there are various types of rust preventive oils. Some rust preventive oils also contain elements such as sulfur and chlorine. Carbonate can be decomposed into oxides and carbon dioxide at high temperatures. Carbon dioxide can combine with hydrogen in the molten pool to form gaseous water and carbon monoxide, reducing the content of diffusible hydrogen. The oxides can combine with sulfur and chlorine generated by the pyrolysis of the rust preventive oil to play a role in fixing sulfur and chlorine, and at the same time can double-block the hydrogen source with copper oxide.

[0018] Optionally, the fixative further includes fluoride and silica, and the mass ratio of fluoride, silica, and carbonate decomposable at high temperature is 1:0.3 - 0.5:1.5 - 2.

[0019] In the above technical solution, fluoride can reduce the viscosity of the slag, form eutectics with silica to promote gas evolution, combine with hydrogen to generate hydrogen fluoride to reduce hydrogen diffusion, and at the same time, fluoride and silica can also form silicon tetrafluoride (SiF 4 ) gas to disperse the oil vapor on the surface of the molten pool and inhibit the incorporation of hydrogen. The fluorocarbon chain in polytetrafluoroethylene can form an oil-repellent surface with fluoride to block the penetration of oil stains, and the sodium oxide decomposed from sodium gluconate can form sodium silicate with low melting point with silica to improve the slag coverage.

[0020] Optionally, the rapid reaction layer further includes stearate, and the mass percentage of stearate is 0.1 - 0.3% of the total mass percentage of the double-layer flux cored wire.

[0021] In the above technical solution, stearate can be used as an isolating agent to effectively isolate the inner and outer layer flux cored wire powders and prevent the mixing of the inner and outer layer powders.

[0022] In a second aspect, a method for preparing a stainless steel flux cored wire provided by the present invention adopts the following technical solution:

[0023] A method for preparing a stainless steel flux cored wire includes the following steps:

[0024] Treatment of raw materials: Wipe the stainless steel strip with acetone to remove the surface floating oil, and dry and mix evenly the powders of the rapid reaction layer and the alloy transition layer respectively;

[0025] Primary U-groove forming and filling of alloy transition layer powder: Roll the stainless steel strip into a primary U-groove, fill it with the alloy transition layer mixed powder, with a filling density of 4.0 - 4.5 g / cm 3 , gently press and level it under a pressure of 0.4 - 0.6 MPa to form a flux cored wire layer with a thickness of 0.12 - 0.15 mm, gradually press the stainless steel strip to a closed state, with a pressure of 20 - 25 kN, and scan along the weld with a 1064 nm, 500 W fiber laser to form a microfusion zone with a width of 0.08 - 0.01 mm to obtain the first wire;

[0026] Secondary U-groove forming and filling of rapid reaction layer powder: Continue to roll the first wire into a secondary U-groove, and fill the rapid reaction layer mixed powder into the secondary U-groove, with a filling density of 3.8 - 4.2 g / cm 3, under a pressure of 0.4 - 0.6 MPa, gently press and flatten to form a flux-cored layer with a thickness of 0.06 - 0.10 mm. Gradually press the stainless steel strip until it is in a closed state with a pressure of 20 - 25 kN. Use a 1064 nm, 500 W fiber laser to scan along the weld to form a microfusion zone with a width of 0.08 - 0.10 mm, and obtain the second wire.

[0027] Drawing process: Continuously roll the second wire through multiple passes of reducing-diameter drawing to form a wire with a diameter of 1.2 - 1.6 mm, and ultrasonically clean to remove the surface floating powder to obtain the stainless steel flux-cored wire.

[0028] Optionally, the rolling forming angle of the primary U-shaped groove is 55 - 60°, and the rolling forming angle of the secondary U-shaped groove is 85 - 90°.

[0029] In the above technical solution, the large angle of 85 - 90° of the opening provides a wide filling cross-section to ensure the full filling of the fast reaction layer powder. The narrow angle of 55 - 60° will ensure 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 when filling and the fast reaction layer powder. At the same time, the cross-sectional shape after forming at 55 - 60° is closer to the final circle, reducing the drawing deformation amount.

[0030] Optionally, the reduction rate of each drawing is 5 - 10%, and a graphite emulsion with a concentration of 8 - 10% is used as a lubricant during each drawing process.

[0031] On the one hand, multiple passes of drawing can avoid stress concentration caused by large single deformation through gradual reduction of diameter, and can improve the tensile strength and hardness of the wire; on the other hand, defects such as pores and scratches on the surface of the wire can be gradually eliminated during each drawing process to reduce friction; on the third hand, multiple passes of reducing-diameter drawing combined with a nano-graphite emulsion lubricant can reduce the risk of wire breakage and improve the surface finish of the wire. Using a graphite emulsion with a medium concentration, if the concentration is too low, it will result in insufficient lubrication, and if the concentration is too high, it may clog the equipment.

[0032] Thirdly, the present invention provides an application of a stainless steel flux-cored wire and a stainless steel flux-cored wire prepared by a preparation method of a stainless steel flux-cored wire in the petrochemical industry, shipbuilding industry, automobile manufacturing industry, food machinery and medical device manufacturing industry, and energy storage and transportation equipment industry.

[0033] In summary, the present invention includes at least one of the following beneficial technical effects:

[0034] The rapid reaction layer is formed by adding an inorganic composition. Copper oxide in the inorganic composition decomposes at high temperatures to generate active oxygen, which oxidizes the hydrocarbons in the rust preventive oil to produce gaseous carbon dioxide and water. These can overflow with the boiling of the molten pool and are insoluble in the metal, thus avoiding hydrogen embrittlement. Ferric oxide acts as an auxiliary oxidant to enhance the oxidation rate of the high-viscosity rust preventive oil.

[0035] The rapid reaction layer is formed by adding high-temperature decomposable organic substances. Polytetrafluoroethylene micropowder in the high-temperature decomposable organic substances decomposes at high temperatures to generate CF 4 and C 2 F 4 gases, which combine with the hydrogen generated by the pyrolysis of the rust preventive oil to form hydrogen fluoride gas and overflow. Trisodium citrate (CH 5 Na 3 O 7 ) carbonizes at high temperatures to form a porous carbon skeleton, which adsorbs oil and grease molecules and catalyzes their oxidation. The sodium ions therein can stabilize the arc and reduce spatter. The fluoride decomposed from the polytetrafluoroethylene powder (such as CaF 2 ) and the Na 2 0 formed by trisodium citrate form sodium hexafluoroaluminate (Na 3 AlF 6 ), reducing the surface tension of the molten slag and improving the bubble escape property.

[0036] 3. The alloy transition layer is formed by adding niobium carbide, which can refine the weld grains, improve the strength and toughness of the welding wire, preferentially combine with carbon to avoid the precipitation of chromium carbides, and at the same time remain dispersedly distributed in the welding molten pool to control the excessive growth of grains and reduce the content of diffusible hydrogen.

[0037] 4. The alloy transition layer is formed by adding rare earth oxides, which 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. Specific Embodiments

[0038] The present invention will be further described in detail below in conjunction with embodiments.

[0039] The materials used in the following embodiments can all be obtained through market purchases.

[0040] Example 1: This example discloses a stainless steel flux-cored wire and its preparation method.

[0041] The stainless steel flux-cored wire includes a stainless steel strip and a double-layered flux core. Among them, the double-layered flux core is filled in the stainless steel strip, and the filling amount of the double-layered flux core is 20% of the total mass of the stainless steel flux-cored wire; the double-layered flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. The rapid reaction layer includes an oil stain oxidant, and the mass percentage of the oil stain oxidant is 12% of the total mass percentage of the double-layered flux core. The oil stain oxidant includes a high-temperature decomposition type organic matter and an inorganic composition. The mass ratio of the high-temperature decomposition type organic matter to the inorganic composition is 1:15. The inorganic composition includes copper oxide and ferric oxide with a mass ratio of 1:1. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder and trisodium citrate with a mass ratio of 1:3. By the total mass percentage of the double-layered flux core, the alloy transition layer includes 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.

[0042] In the embodiment of the present application, the stainless steel strip is selected as a 321L type stainless steel strip. In other embodiments, the stainless steel strip can also be selected as a 316L type stainless steel strip, an E304L type stainless steel strip, etc. The niobium carbide is nano niobium carbide, and the rare earth oxide is selected as lanthanum oxide. In other embodiments, the rare earth oxide can also be selected as cerium oxide, yttrium oxide, etc.

[0043] A preparation method of a stainless steel flux-cored wire includes the following steps:

[0044] S1. Treatment of raw materials: Wipe the 321L type stainless steel strip with acetone to remove the surface floating oil, and dry and mix evenly the powders of the rapid reaction layer and the alloy transition layer respectively;

[0045] S2. Primary U-groove preforming and filling the alloy transition layer powder: Roll the stainless steel strip into a primary U-groove at 90°, fill the alloy transition layer mixed powder into it, and the filling density is 4.3 g / cm 3 , gently press and level it under a pressure of 0.5 MPa to form a flux core layer with a thickness of 0.14 mm, gradually press the stainless steel strip to a closed state, with a pressure of 22 kN, and scan along the weld with a 1064 nm, 500 W fiber laser to form a 0.01 mm wide microfusion zone to obtain the first wire;

[0046] S3. Secondary U-groove preforming and filling the rapid reaction layer powder: Roll the first wire into a secondary U-groove at 60°, and fill the rapid reaction layer mixed powder into the secondary U-groove, with a filling density of 4.0 g / cm 3, lightly press and flatten at a pressure of 0.5 MPa to form a flux-cored layer with a thickness of 0.10 mm, gradually press the stainless steel strip until it is in a closed state, with a pressure of 20 - 25 kN, and use a 1064 nm, 500 W fiber laser to scan along the weld to form a microfusion zone with a width of 0.08 - 0.01 mm to obtain the second wire;

[0047] S4. Drawing process: Continuously roll the second wire through multiple passes of reducing-diameter drawing to form a wire with a diameter of 1.2 - 1.6 mm, and ultrasonically clean to remove the surface floating powder to obtain the stainless steel flux-cored wire 1#.

[0048] Example 2: This example discloses a stainless steel flux-cored wire and its preparation method.

[0049] The stainless steel flux-cored wire includes an E304L type stainless steel strip and a double-layer flux core. Among them, the double-layer flux core is filled in the E304L type 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 wire; the double-layer flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. The rapid reaction layer includes an oil stain oxidant, and the mass percentage of the oil stain oxidant is 12% of the total mass percentage of the double-layer flux core. The oil stain oxidant includes a high-temperature decomposition type organic matter and an inorganic composition, and the mass ratio of the high-temperature decomposition type organic matter to the inorganic composition is 1:20. The inorganic composition includes copper oxide and ferric oxide with a mass ratio of 1.5:1. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder and trisodium citrate with a mass ratio of 1:5. Calculated by the total mass percentage of the double-layer flux core, the alloy transition layer includes 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.

[0050] The preparation method of this stainless steel flux-cored wire is the same as that of Example 1.

[0051] Example 3: This example discloses a stainless steel flux-cored wire and its preparation method.

[0052] The stainless steel flux-cored wire includes a 316L type stainless steel strip and a double-layer flux core. Among them, 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 wire; the double-layer flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. The rapid reaction layer includes an oil stain oxidant, and the mass percentage of the oil stain oxidant is 11.5% of the total mass percentage of the double-layer flux core. The oil stain oxidant includes a high-temperature decomposition type organic matter and an inorganic composition. The mass ratio of the high-temperature decomposition type organic matter to the inorganic composition is 1:18. The inorganic composition includes copper oxide and ferric oxide with a mass ratio of 1.5:1. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder and trisodium citrate with a mass ratio of 1:4. Calculated by the total mass percentage of the double-layer flux core, 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.

[0053] The preparation method of this stainless steel flux-cored wire is the same as that of Example 1.

[0054] Example 4: This example discloses a stainless steel flux-cored wire and its preparation method.

[0055] The stainless steel flux-cored wire includes a 316L type stainless steel strip and a double-layer flux core. Among them, 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 wire; the double-layer flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. The rapid reaction layer includes an oil stain oxidant, and the mass percentage of the oil stain oxidant is 11.5% of the total mass percentage of the double-layer flux core. The oil stain oxidant includes a high-temperature decomposition type organic matter and an inorganic composition. The mass ratio of the high-temperature decomposition type organic matter to the inorganic composition is 1:18. The inorganic composition includes copper oxide, manganese dioxide, and ferric oxide with a mass ratio of 8:1:4. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder and trisodium citrate with a mass ratio of 1:4. Calculated by the total mass percentage of the double-layer flux core, 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.

[0056] The preparation method of this stainless steel flux-cored wire is the same as that of Example 1.

[0057] Example 5: This example discloses a stainless steel flux-cored wire and its preparation method.

[0058] The stainless steel flux-cored wire includes a 316L type stainless steel strip and a double-layer flux core. Among them, 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 wire; the double-layer flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. The rapid reaction layer includes an oil stain oxidant, and the mass percentage of the oil stain oxidant is 11.5% of the total mass percentage of the double-layer flux core. The oil stain oxidant includes a high-temperature decomposition type organic matter and an inorganic composition. The mass ratio of the high-temperature decomposition type organic matter to the inorganic composition is 1:18. The inorganic composition includes copper oxide and iron sesquioxide with a mass ratio of 1.5:1. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder, trisodium citrate, phthalocyanine copper, and sodium gluconate with a mass ratio of 1:4:0.3:4. Calculated by the total mass percentage of the double-layer flux core, 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.

[0059] Example 6: This example discloses a stainless steel flux-cored wire and a preparation method thereof.

[0060] The stainless steel flux-cored wire includes a 316L type stainless steel strip and a double-layer flux core. Among them, 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 wire; the double-layer flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. The rapid reaction layer includes an oil stain oxidant, and the mass percentage of the oil stain oxidant is 11.5% of the total mass percentage of the double-layer flux core. The oil stain oxidant includes a high-temperature decomposition type organic matter and an inorganic composition. The mass ratio of the high-temperature decomposition type organic matter to the inorganic composition is 1:18. The inorganic composition includes copper oxide, manganese dioxide, and iron sesquioxide with a mass ratio of 8:1:4. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder, trisodium citrate, phthalocyanine copper, and sodium gluconate with a mass ratio of 1:4:0.3:4. Calculated by the total mass percentage of the double-layer flux core, 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.

[0061] The preparation method of this stainless steel flux-cored wire is the same as that of Example 1.

[0062] Example 7: This example discloses a stainless steel flux-cored wire and a preparation method thereof.

[0063] The stainless steel flux-cored wire includes a 316L type stainless steel strip and a double-layer flux core. Among them, 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 wire; the double-layer flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. By mass percentage of the total mass of the double-layer flux core, the rapid reaction layer includes 10% of an oil stain oxidant and 5% of a fixing agent. The oil stain oxidant includes a high-temperature decomposition type organic matter and an inorganic composition. 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 iron oxide with a mass ratio of 1.5:1. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder and trisodium citrate with a mass ratio of 1:4. The fixing agent includes calcium carbonate. In other embodiments, carbonate that can be decomposed at high temperature can also be selected as 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.

[0064] The preparation method of this stainless steel flux-cored wire is the same as that of Example 1.

[0065] Example 8: This example discloses a stainless steel flux-cored wire and its preparation method.

[0066] The stainless steel flux-cored wire includes a 316L type stainless steel strip and a double-layer flux core. Among them, 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 wire; the double-layer flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. By mass percentage of the total mass of the double-layer flux core, the rapid reaction layer includes 10% of an oil stain oxidant and 5% of calcium carbonate. The oil stain oxidant includes a high-temperature decomposition type organic matter and an inorganic composition. 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 iron oxide with a mass ratio of 1.5:1. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder, trisodium citrate, phthalocyanine copper, and sodium gluconate with a mass ratio of 1:4:0.3:4. By mass percentage of the total mass of the double-layer flux 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.

[0067] The preparation method of this stainless steel flux-cored wire is the same as that of Example 1.

[0068] Example 9: This example discloses a stainless steel flux-cored wire and its preparation method.

[0069] The stainless steel flux-cored wire includes a 316L type stainless steel strip and a double-layer flux core. Among them, 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 wire; the double-layer flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. By mass percentage of the total mass of the double-layer flux core, the rapid reaction layer includes 10% of oil stain oxidant and 5% of curing agent. The fixing agent includes calcium fluoride, silicon dioxide, and calcium carbonate with a mass ratio of 1:0.4:1.5. The calcium fluoride is selected as the fluoride. In other embodiments, the fluoride can also be selected from potassium fluoride and lithium fluoride. The oil stain oxidant includes high-temperature decomposition type organic matter and inorganic composition. 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 iron sesquioxide with a mass ratio of 1.5:1. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder and trisodium citrate with a mass ratio of 1:4. By mass percentage of the total mass of the double-layer flux core, the alloy transition layer includes 71.5% of 316L stainless steel powder, 3% of molybdenum powder, 1% of silicon powder, 5% of nickel powder, 2% of manganese powder, 0.5% of nano niobium carbide, and 2% of lanthanum oxide.

[0070] The preparation method of this stainless steel flux-cored wire is the same as that of Example 1.

[0071] Example 10: This example discloses a stainless steel flux-cored wire and its preparation method.

[0072] The stainless steel flux-cored wire includes a 316L type stainless steel strip and a double-layer flux core. Among them, 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 wire; the double-layer flux core includes a rapid reaction layer on the outer layer and an alloy transition layer on the inner layer. By mass percentage of the total mass of the double-layer flux core, the rapid reaction layer includes 10% of oil stain oxidant and 5% of curing agent. The fixing agent includes calcium fluoride, silicon dioxide, and calcium carbonate with a mass ratio of 1:0.4:1.5. The oil stain oxidant includes high-temperature decomposition type organic matter and inorganic composition. 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 iron sesquioxide with a mass ratio of 1.5:1. The high-temperature decomposition type organic matter includes polytetrafluoroethylene micropowder, trisodium citrate, phthalocyanine copper, and sodium gluconate with a mass ratio of 1:4:0.3:4. By mass percentage of the total mass of the double-layer flux core, the alloy transition layer includes 71.5% of 316L stainless steel powder, 3% of molybdenum powder, 1% of silicon powder, 5% of nickel powder, 2% of manganese powder, 0.5% of nano niobium carbide, and 2% of lanthanum oxide.

[0073] The preparation method of this stainless steel flux-cored wire is the same as that of Example 1.

[0074] Example 11: This example discloses a stainless steel flux-cored wire and its preparation method.

[0075] The stainless steel flux-cored wire comprises a 316L type stainless steel strip and a double-layer flux core. Among them, 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 wire; the double-layer flux core includes a rapid reaction layer located on the outer layer and an alloy transition layer located on the inner layer. Calculated by the total mass percentage of the double-layer flux core, the rapid reaction layer includes 10% oil stain oxidant, 5% curing agent, 0.2% stearate. In this example, calcium stearate is selected as the stearate. In other examples, sodium stearate, zinc stearate, etc. can also be selected as the stearate. The fixing agent includes calcium fluoride, silicon dioxide, and calcium carbonate with a mass ratio of 1:0.4:1.5. The oil stain oxidant includes a high-temperature decomposition type organic substance and an inorganic composition. The mass ratio of the high-temperature decomposition type organic substance to the inorganic composition is 1:18. The inorganic composition is copper oxide and ferric oxide with a mass ratio of 1.5:1. The high-temperature decomposition type organic substance includes polytetrafluoroethylene micropowder, trisodium citrate, phthalocyanine copper, and sodium gluconate with a mass ratio of 1:4:0.3:4. Calculated by the total mass percentage of the double-layer flux 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.

[0076] The preparation method of this stainless steel flux-cored wire is the same as that of Example 1.

[0077] Comparative Example 1: This comparative example provides a comparative stainless steel flux-cored wire D1. The stainless steel flux-cored wire comprises a 316L type stainless steel strip and a single-layer flux core. Among them, 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 wire; calculated by the total mass percentage of the single-layer flux core, the single-layer flux core includes 10% oil stain oxidant, 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, and 2% lanthanum oxide. The fixing agent includes calcium fluoride, silicon dioxide, and calcium carbonate with a mass ratio of 1:0.4:1.5. The oil stain oxidant includes a high-temperature decomposition type organic substance and an inorganic composition. The mass ratio of the high-temperature decomposition type organic substance to the inorganic composition is 1:18. The inorganic composition is copper oxide and ferric oxide with a mass ratio of 1.5:1. The high-temperature decomposition type organic substance includes polytetrafluoroethylene micropowder, trisodium citrate, phthalocyanine copper, and sodium gluconate with a mass ratio of 1:4:0.3:4.

[0078] A preparation method of a comparative stainless steel flux-cored wire D1 includes the following steps:

[0079] S1. Treatment of raw materials: Wipe the 321L type stainless steel strip with acetone to remove the surface floating oil, and dry and mix the above-mentioned powders evenly respectively;

[0080] S2. U-groove preforming and powder filling: Roll the stainless steel strip into a U-groove at 90°, fill it with the mixed powder, and the filling density is 4.3 g / cm 3 , gently press and flatten it under a pressure of 0.5 MPa to form a flux-cored layer with a thickness of 0.2 mm, gradually press and combine the stainless steel strip until it is in a closed state, with a pressure of 22 kN, and scan along the weld with a 1064 nm, 500 W fiber laser to form a microfusion zone with a width of 0.01 mm to obtain the first welding wire;

[0081] S3. Drawing process: Continuously roll the first welding wire through multi-pass reducing drawing to form a welding wire with a diameter of 1.2 - 1.6 mm, and ultrasonically clean it to remove the surface floating powder to obtain the comparative stainless steel flux-cored welding wire D1.

[0082] 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 in Example 11, except that: the oil stain oxidant does not include high-temperature decomposition type organic substances. Its preparation method is the same as that of Example 1.

[0083] 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 in Example 11, except that: the oil stain oxidant does not include inorganic compositions. Its preparation method is the same as that of Example 1.

[0084] 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 in Example 11, except that: the alloy transition layer does not include niobium carbide. Its preparation method is the same as that of Example 1.

[0085] 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 in Example 11, except that: the alloy transition layer does not include rare earth oxides. Its preparation method is the same as that of Example 1.

[0086] 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 in Example 11, except that: the inorganic composition only includes iron(III) oxide. Its preparation method is the same as that of Example 1.

[0087] 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 in Example 11, except that: zinc oxide is selected to replace copper oxide. Its preparation method is the same as that of Example 1.

[0088] Comparative Example 8: This comparative example provides a comparative stainless steel flux-cored wire D8, which has the same components as the stainless steel flux-cored wire in Example 11, except that: high-temperature non-decomposable organic matter polybenzimidazole is selected to replace high-temperature decomposable organic matter polytetrafluoroethylene micropowder and trisodium citrate. Its preparation method is the same as that of Example 1.

[0089] Comparative Example 9: This comparative example provides a comparative stainless steel flux-cored wire D9, which has the same components as the stainless steel flux-cored wire in Example 11, except that: titanium oxide is selected to replace rare earth oxides. Its preparation method is the same as that of Example 1.

[0090] Welding tests were carried out on the stainless steel flux-cored wires #1-#11 of Examples 1-11 and the comparative stainless steel flux-cored wires D1-D9 of Comparative Examples 1-9, as shown in Table 1. The welding properties are shown in Table 2, including porosity test, arc stability test, welding spatter amount test, diffusible hydrogen test (mercury method), tensile strength test, groove welding experiment crack test, corrosion resistance test, and surface oil stain test (drip diffusion method).

[0091] Table 1

[0092] Voltage (V) Current (A) Welding speed (cm / min) Stickout length (mm) Welding time (h) Welding wind speed (m / s) Relative humidity (%) 29 250 10 20 3 ≤2 ≤90

[0093] Table 2

[0094] Example performance Diffused hydrogen content (mL / 100g) Weld porosity rate (%) Groove welding experiment crack (%) Tensile strength (MPa) Corrosion resistance Arc stability Spatter rate (%) Water droplet 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 Example 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 Bead-like Comparative example 2 3.24 3.33 3.19 641 Excellent Excellent 3.8 Bead-like Comparative example 3 3.40 3.56 3.32 595 Good Good 4.3 Bead-like Comparative example 4 2.59 2.43 2.51 623 Excellent Excellent 3.2 Bead-like Comparative example 5 2.71 2.79 2.60 633 Excellent Excellent 3.5 Bead-like Comparative example 6 3.19 2.85 2.87 647 Excellent Excellent 3.6 Bead-like Comparative example 7 3.21 2.91 2.92 645 Excellent Excellent 3.7 Bead-like Comparative example 8 3.20 2.89 2.90 642 Excellent Excellent 3.8 Bead-like Comparative example 9 2.48 2.37 2.28 649 Excellent Excellent 3.1 Bead-like

[0095] From the data of Examples 1-3, especially the data of Example 3, it can be seen that through the reasonable proportioning of the constituent materials of the stainless steel double-layer flux-cored wire, the diffusible hydrogen content of the stainless steel flux-cored wire of the present application is low, the weld porosity is small, the crack is small, and the tensile strength, corrosion resistance, arc stability, and spatter rate are all excellent. At the same time, the water droplet diffuses into a round shape, indicating that there is no oil stain on the surface, effectively avoiding the formation of diffusible hydrogen from the compounds in the rust preventive oil remaining on the surface of the wire during welding and causing hydrogen embrittlement.

[0096] Comparing Example 3 with Example 4 and Example 5 with Example 6, the composition of the inorganic composition is slightly different, but the properties of the obtained stainless steel flux-cored wires are not much different. Therefore, manganese dioxide can replace part of copper oxide to participate in the reaction.

[0097] Comparing Example 5 with Example 3 and Example 7 and 8, the composition of the high-temperature decomposable organic matter is different, and the properties of the obtained stainless steel flux-cored wires are all excellent. Thus, it shows that phthalocyanine copper releases copper ions at high temperature, catalyzes the complete oxidation of hydrocarbons in the rust preventive oil, and at the same time the generated nitrogen heterocyclic structure can adsorb sulfides in the rust preventive oil. Sodium gluconate decomposes into sodium carbonate and activated carbon under high temperature conditions, and sodium carbonate can react with chloride ions in the rust preventive oil to play a role in fixing chlorine.

[0098] 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.

[0099] 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 at the same time combine with hydrogen to generate hydrogen fluoride, reduce hydrogen diffusion, and at the same time fluoride and silicon dioxide can also form silicon fluoride (SiF 4 ) gas, disperse the oil vapor on the surface of the molten pool and inhibit the integration of hydrogen.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] The above are all preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby. Therefore, all equivalent changes made according to the structure, shape and principle of the present invention shall be covered within 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.