Basic flux-cored welding wire and preparation method and welding method thereof

Abstract

The present invention provides an alkaline flux-cored welding wire, a preparation method thereof, and a welding method, specifically relating to the field of welding materials. The raw material composition of the flux-cored welding wire and the weight percentage of each component are as follows: 20-30 wt% barium fluoride, 5-7 wt% lithium fluoride, 2-3 wt% fluorite, 2-3 wt% rutile, 10-15 wt% aluminum powder, 2-3 wt% dead-burned magnesia, 8-10 wt% magnesium powder, 2-4 wt% ferrosilicon, 6-8 wt% manganese metal, 3-5 wt% chromium metal, 12-15 wt% nickel powder, 6-8 wt% ferromolybdenum, and the balance is atomized iron powder. The alkaline flux-cored welding wire of the present invention utilizes an alkaline slag system, resulting in a pure weld with few impurities, excellent mechanical properties and low-temperature impact toughness, good arc stability, minimal spatter, beautiful weld formation, good slag removal, and excellent welding process performance. It also has a high deposition rate and deposition rate, low diffusible hydrogen content, and excellent crack resistance, making it suitable for welding 830 MPa-grade high-strength steel.

Description

Technical Field

[0001] The present invention relates to the field of welding materials, and in particular to a basic flux-cored welding wire and a preparation method thereof. Background Art

[0002] High-strength steel, with its advantages of light weight, low manufacturing cost, and ease of processing and transportation, is widely used in various fields. In recent years, 830Mpa-grade high-strength steel has become the primary structural material for the lightweight design and manufacturing of equipment in fields such as engineering machinery, oil pipelines, and the military industry. Flux-cored welding wire offers advantages such as low welding spatter, stable arc combustion, and aesthetically pleasing weld formation. Its use in gas shielded welding of high-strength steel can improve production efficiency and reduce welding costs, offering promising development prospects. However, currently, domestically available flux-cored welding wire for high-strength steel is relatively limited and largely dependent on imports. Furthermore, traditional acidic flux-cored wire is susceptible to moisture absorption, has a high level of diffusible hydrogen, and is prone to cracking after welding. Therefore, the development of flux-cored welding wire for high-strength steel is an urgent need for the development of welding materials. Summary of the Invention

[0003] In view of the above shortcomings of the prior art, the present invention provides a basic flux-cored welding wire and a preparation method and a welding method thereof, so as to improve the problem that the flux-cored welding wire used for high-strength steel welding has high diffusible hydrogen and is prone to cracking after welding.

[0004] To achieve the above-mentioned and other related purposes, the present invention provides a basic flux-cored welding wire, comprising a steel strip sheath and a flux core coated within the steel strip sheath. The raw material composition of the flux core and the weight percentage of each component are as follows: 20-30 wt% barium fluoride, 5-7 wt% lithium fluoride, 2-3 wt% fluorite, 2-3 wt% rutile, 10-15 wt% aluminum powder, 2-3 wt% dead-burned magnesia, 8-10 wt% magnesium powder, 2-4 wt% ferrosilicon, 6-8 wt% metallic manganese, 3-5 wt% metallic chromium, 12-15 wt% nickel powder, 6-8 wt% ferromolybdenum, and the balance is atomized iron powder.

[0005] In one example of the present invention, the purity of the barium fluoride is ≥98%, the purity of the lithium fluoride is ≥99%, the calcium fluoride (CaF2) content in the fluorite is ≥95wt%, the titanium dioxide (TiO2) content in the rutile is ≥95wt%, the purity of the aluminum powder is ≥97%, the magnesium oxide (MgO) content in the dead-burned magnesia is ≥90wt%, the purity of the magnesium powder is ≥98%, the silicon (Si) content in the ferrosilicon is 42-47wt%, the purity of the metallic manganese is ≥99.8%, the purity of the metallic chromium is ≥99%, the purity of the nickel powder is ≥99%, the molybdenum (Mo) content in the ferromolybdenum is ≥55wt%, and the purity of the atomized iron powder is ≥98%.

[0006] In one example of the present invention, the outer skin of the steel strip is made of low-carbon steel strip, and the carbon (C) content in the outer skin of the steel strip is ≤0.01wt%, the silicon (Si) content is ≤0.02wt%, the phosphorus (P) content is ≤0.015wt%, the sulfur (S) content is ≤0.015wt%, and the manganese (Mn) content is 0.10~0.25wt%.

[0007] In an example of the present invention, the weight of the flux core accounts for 15-17% of the total weight of the basic flux-cored welding wire.

[0008] In an example of the present invention, the diameter of the basic flux-cored welding wire is 1.2 mm to 1.6 mm.

[0009] In one example of the present invention, the deposited metal of the basic flux-cored welding wire has a carbon (C) content of ≤0.15wt%, a manganese (Mn) content of 1.20-2.25wt%, a silicon (Si) content of ≤0.08wt%, a nickel (Ni) content of 1.75-2.60wt%, a molybdenum (Mo) content of 0.20-0.65wt%, a phosphorus (P) content of ≤0.03wt%, a sulfur (S) content of ≤0.03wt%, and an aluminum (Al) content of ≤1.80wt%.

[0010] The present invention also provides a method for preparing a basic flux-cored welding wire, comprising the following steps:

[0011] Weigh each component according to the ratio and mix them evenly to prepare the drug core;

[0012] Rolling the outer skin of the steel strip into a U-shaped groove, and filling the core into the U-shaped groove and closing it;

[0013] The outer skin of the steel strip filled with the flux core is drawn and reduced in diameter to a desired specification to obtain the basic flux cored welding wire.

[0014] In one example of the present invention, after weighing each component, the components are further dried. The drying process includes: keeping aluminum powder, ferrosilicon, metallic manganese, metallic chromium, nickel powder, ferromolybdenum, and atomized iron powder at 160-180°C for 115-125 minutes, keeping barium fluoride, lithium fluoride, fluorite, dead-burned magnesia, and magnesium powder at 390-410°C for 355-365 minutes, and keeping rutile at 840-860°C for 355-365 minutes.

[0015] The invention also provides a welding method for a basic flux-cored wire, in which welding is performed under the protection of carbon dioxide gas.

[0016] In an example of the present invention, the welding conditions are as follows: the shielding gas is 100% CO2, the shielding gas flow rate is 15-25 L / min, the welding voltage is 25-35 V, and the welding current is 160-350 A.

[0017] The alkaline flux-cored welding wire of the present invention adopts an alkaline slag system mainly composed of fluorides. During welding, the F element combines with the harmful H element in the weld to generate HF gas that escapes, thereby reducing the diffusible hydrogen content of the deposited metal. By regulating the drying process of each powder, the water content of the powder is reduced, and the diffusible hydrogen content of the deposited metal is further reduced. Adding appropriate amounts of Li and Al elements can effectively stabilize the arc, reduce spatter, and ensure excellent welding processability. Adding appropriate amounts of Mn, Si, and Al elements can effectively reduce the oxygen content of the weld. Adding alloying elements Cr, Ni, and Mo can reduce the tendency of the weld to harden the structure, increase the amount of acicular ferrite in the weld, reduce the amount of proeutectoid ferrite and lamellar structure, and refine the microstructure of the coarse-grained and fine-grained areas of the weld, so that the strength of the weld increases linearly while maintaining good low-temperature toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 FIG. 1 is a flow chart of the preparation of the basic flux-cored welding wire according to one embodiment of the present invention. DETAILED DESCRIPTION

[0020] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following examples and the features in the examples can be combined with each other unless they conflict. It should also be understood that the terms used in the examples of the present invention are for the purpose of describing specific embodiments, not for the purpose of limiting the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0021] When referring to a numerical range herein, unless otherwise specified, the distribution of the values ​​within the numerical range is considered continuous and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between the two numerical endpoints. When multiple numerical ranges are provided to describe a feature or characteristic, these numerical ranges may be combined.

[0022] It should be noted that, unless otherwise specified, "%" and "wt%" herein represent mass percentage.

[0023] The invention provides an alkaline flux-cored welding wire. The alkaline flux-cored welding wire comprises a steel strip outer skin and a flux core coated in the steel strip outer skin. The raw material composition of the flux core and the weight percentage of each component are as follows: 20-30wt% of barium fluoride, 5-7wt% of lithium fluoride, 2-3wt% of fluorite, 2-3wt% of rutile, 10-15wt% of aluminum powder, 2-3wt% of dead-burned magnesia, 8-10wt% of magnesium powder, 2-4wt% of ferrosilicon, 6-8wt% of metallic manganese, 3-5wt% of metallic chromium, 12-15wt% of nickel powder, 6-8wt% of ferromolybdenum, and the balance is atomized iron powder.

[0024] The functions of the components of the core are as follows:

[0025] The purity of barium fluoride is ≥98%, and the purity of lithium fluoride is ≥99%. Barium fluoride and lithium fluoride have slag-forming, gas-forming, deoxidizing and arc-stabilizing effects, ensuring good welding processability. At the same time, the barium fluoride slag coagulates quickly, which can ensure good all-position welding.

[0026] The TiO2 content in rutile is ≥95wt%, which plays a major role in slag formation and arc stabilization during welding. Rutile has good thermal slag removal, stable arc, calm weld pool, good directional welding, and excellent weld formation.

[0027] Aluminum powder, with a purity of ≥97%, primarily functions as a deoxidizer. Increasing the aluminum content in the deposited metal significantly decreases its oxygen and nitrogen contents, significantly improving its porosity resistance. Aluminum effectively reduces weld porosity sensitivity, both due to its strong deoxidizing properties and its strong binding with nitrogen, forming stable nitrides that are insoluble in the weld metal but melt in the slag. A certain amount of aluminum ensures porosity resistance.

[0028] The MgO content in the dead-burned magnesia is ≥90wt%, which has the functions of slag formation, adjusting the basicity, viscosity, fluidity of the slag and improving the weld formation.

[0029] The Mg content in the magnesium powder is ≥98wt%. Mg, as a strong deoxidizer, can improve the low-temperature impact toughness of the flux-cored welding wire.

[0030] The Si content in ferrosilicon is 42-47 wt%, which is the main deoxidizer. Adding an appropriate amount can improve the process and deoxidation.

[0031] The Mn content in metallic manganese is ≥99.8wt%. Mn is used for alloying, deoxidation and desulfurization, and has a solid solution strengthening effect on the weld metal, increasing the strength and crack resistance of the weld metal, improving the elongation of the weld, and helping to improve low-temperature impact toughness.

[0032] The Cr content in metallic chromium is ≥99wt%. Cr is used as alloying to give the weld better resistance to intergranular corrosion.

[0033] The Ni content in the nickel powder is ≥99wt%. Ni is used as an alloy to reduce the proeutectoid ferrite in the weld metal, increase the acicular ferrite, improve the stability of the austenite, and improve the intergranular corrosion resistance of the weld.

[0034] The Mo content in ferromolybdenum is ≥55wt%, which can transition Mo into the weld and improve the weld strength.

[0035] The purity of atomized iron powder is ≥98%, which can not only improve the overall fluidity of powder preparation and ensure uniform filling and molding of powder, but also effectively improve the conductivity of the flux core, improve the welding wire deposition efficiency, and ensure good welding processability.

[0036] In one embodiment, the components of the flux core are dried before use to reduce the moisture content of the flux core, thereby lowering the hydrogen content of the basic flux-cored welding wire and further reducing weld crack sensitivity. The drying conditions for the flux core components are as follows: aluminum powder, ferrosilicon, manganese metal, chromium metal, nickel powder, ferromolybdenum, and atomized iron powder are kept at 160-180°C for 115-125 minutes; barium fluoride, lithium fluoride, fluorite, dead-burned magnesia, and magnesium powder are kept at 390-410°C for 355-365 minutes; and rutile is kept at 840-860°C for 355-365 minutes. The dried flux core should be stored in a dry, clean environment, avoiding exposure to humid air to prevent moisture absorption.

[0037] In one embodiment, the outer skin of the steel strip is made of low carbon steel strip, and the C content of the steel strip outer skin is ≤0.01wt%, the Si content is ≤0.02wt%, the P content is ≤0.015wt%, the S content is ≤0.015wt%, and the Mn content is 0.10-0.25wt%.

[0038] In one embodiment, the weight of the flux core accounts for 15-17% of the total weight of the basic flux-cored welding wire, such as 15%, 16% or 17%. In the present application, the diameter of the basic flux-cored welding wire is 1.2-1.6 mm, such as 1.2 mm, 1.4 mm, 1.5 mm or 1.6 mm.

[0039] In the present application, the C content in the deposited metal of the basic flux-cored welding wire is ≤0.15wt%, the Mn content is 1.20-2.25wt%, the Si content is ≤0.08wt%, the Ni content is 1.75-2.60wt%, the Mo content is 0.20-0.65wt%, the P content is ≤0.03wt%, the S content is ≤0.03wt%, and the Al content is ≤1.80wt%.

[0040] The alkaline flux-cored welding wire of the present invention adopts an alkaline slag system mainly composed of fluorides. During welding, the F element combines with the harmful H element in the weld to generate HF gas that escapes, thereby reducing the diffusible hydrogen content of the deposited metal. By regulating the drying process of each powder, the water content of the flux core is reduced, and the diffusible hydrogen content of the deposited metal is further reduced. Adding appropriate amounts of Li and Al elements can effectively stabilize the arc, reduce spatter, and ensure excellent welding processability. Adding appropriate amounts of Mn, Si, and Al elements can effectively reduce the oxygen content of the weld. Adding alloying elements Cr, Ni, and Mo can reduce the tendency of the weld to harden the structure, increase the amount of acicular ferrite in the weld, reduce the amount of proeutectoid ferrite and lamellar structure, and refine the microstructure of the coarse-grained and fine-grained areas of the weld, so that the strength of the weld increases linearly while maintaining good low-temperature toughness.

[0041] See also Figure 1 The present invention also provides a method for preparing a basic flux-cored welding wire, which is used to prepare the above-mentioned basic flux-cored welding wire. The preparation method comprises the following steps:

[0042] S1. Weigh each component according to the ratio and mix them evenly to prepare the drug core;

[0043] S2, rolling the outer skin of the steel strip into a U-shaped groove, filling the core into the U-shaped groove, and closing it;

[0044] S3. Drawing and reducing the outer skin of the steel strip filled with the flux core to the required specifications to obtain a basic flux-cored welding wire.

[0045] In step S1, the components of the core are weighed according to the following ratios: 20-30wt% barium fluoride, 5-7wt% lithium fluoride, 2-3wt% fluorite, 2-3wt% rutile, 10-15wt% aluminum powder, 2-3wt% dead-burned magnesia, 8-10wt% magnesium powder, 2-4wt% ferrosilicon, 6-8wt% manganese metal, 3-5wt% chromium metal, 12-15wt% nickel powder, 6-8wt% ferromolybdenum, and the remainder is atomized iron powder. In order to reduce the moisture content of the core, the components of the core are dried according to the following drying conditions and then mixed evenly: aluminum powder, ferrosilicon, metallic manganese, metallic chromium, nickel powder, ferromolybdenum, and atomized iron powder are kept at 160-180°C for 115-125 minutes, barium fluoride, lithium fluoride, fluorite, dead-burned magnesia, and magnesium powder are kept at 390-410°C for 355-365 minutes, and rutile is kept at 840-860°C for 355-365 minutes.

[0046] In step S2, the outer sheath of the steel strip is made of low-carbon steel strip, wherein the outer sheath has a carbon content of ≤0.01wt%, a silicon content of ≤0.02wt%, a phosphorus content of ≤0.015wt%, a sulfur content of ≤0.015wt%, and a manganese content of 0.10-0.25wt%. Low-carbon steel strip has excellent plasticity, can better adapt to thermal and mechanical stresses, and reduces the tendency of weld joints to crack. The use of low-carbon steel strip in flux-cored welding wire improves welding process performance, making the welding process more stable, spatter-reduced, and the weld seam more aesthetically pleasing. The width and thickness of the outer sheath of the steel strip are adjusted according to the required flux-cored wire dimensions, for example, the thickness × width of the outer sheath is 0.3mm × 10mm. The ratio of the weight of the flux core to the total weight of the basic flux-cored welding wire is adjusted according to requirements, for example, 15%, 16%, or 17%, or any value within the range of 15% to 17%.

[0047] In step S3, the drawing and reducing process is performed according to conventional procedures in the art and will not be further described here. The basic flux-cored wire is drawn to a suitable size according to welding requirements. For example, the diameter of the basic flux-cored wire can be any size within the range of 1.2 to 1.6 mm, such as 1.2 mm, 1.4 mm, 1.5 mm, or 1.6 mm.

[0048] The present invention also provides a welding method for a basic flux-cored wire. When welding high-strength steel using the basic flux-cored wire of the present application, the welding is performed under the protection of carbon dioxide gas. In one embodiment, 100% CO2 is selected as the shielding gas during welding. In other embodiments, an Ar / CO2 mixed gas can also be selected for shielding. The gas flow rate during welding is 15 to 25 L / min, for example, 15 L / min, 20 L / min, or 25 L / min. The welding voltage is 25 to 35 V, for example, 25 V, 30 V, or 35 V, and the welding current is 160 to 350 A, for example, 160 A, 200 A, 300 A, or 350 A. The welding current and welding voltage are adjusted according to the diameter of the prepared basic flux-cored wire, and the welding current and welding voltage are proportional to the diameter of the basic flux-cored wire.

[0049] The technical solutions of the present invention are described in detail below through several specific examples. Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by conventional methods in the art, and the instruments used in the examples are all commercially available.

[0050] Example 1

[0051] First, the following components were weighed according to the following ratios: 20wt% barium fluoride, 7wt% lithium fluoride, 3wt% fluorite, 2wt% rutile, 15wt% aluminum powder, 3wt% dead-burned magnesia, 8wt% magnesium powder, 2wt% ferrosilicon, 6wt% manganese metal, 3wt% chromium metal, 15wt% nickel powder, 8wt% ferromolybdenum, and 8wt% atomized iron powder. The aluminum powder, ferrosilicon, manganese metal, chromium metal, nickel powder, ferromolybdenum, and atomized iron powder were then heated at 170°C for 120 minutes. The barium fluoride, lithium fluoride, fluorite, dead-burned magnesia, and magnesium powder were heated at 410°C for 350 minutes, and the rutile was heated at 840°C for 365 minutes. The above components were then mixed and uniformly prepared to produce a flux core. The outer sheath of the steel strip was rolled into a U-shaped groove, and the flux core was placed into the groove. The U-shaped groove was closed, and the outer sheath of the flux cored steel strip was drawn and reduced to produce a basic flux-cored welding wire with a diameter of 1.2mm. In this embodiment, the thickness×width of the outer skin of the steel strip is 0.3 mm×10 mm, and the weight of the flux core is 17% of the total weight of the basic flux cored welding wire.

[0052] Example 2

[0053] First, the following components were weighed according to the following ratios: 24wt% barium fluoride, 6wt% lithium fluoride, 3wt% fluorite, 2wt% rutile, 13wt% aluminum powder, 3wt% dead-burned magnesia, 9wt% magnesium powder, 4wt% ferrosilicon, 7wt% manganese metal, 3wt% chromium metal, 14wt% nickel powder, 7wt% ferromolybdenum, and 5wt% atomized iron powder. The aluminum powder, ferrosilicon, manganese metal, chromium metal, nickel powder, ferromolybdenum, and atomized iron powder were then heated at 160°C for 125 minutes. The barium fluoride, lithium fluoride, fluorite, dead-burned magnesia, and magnesium powder were heated at 400°C for 360 minutes, and the rutile was heated at 850°C for 360 minutes. The above components were then mixed and uniformly prepared to produce a flux core. The outer sheath of the steel strip was rolled into a U-shaped groove, and the flux core was filled into the groove. The U-shaped groove was closed, and the outer sheath of the flux cored steel strip was drawn and reduced to produce a basic flux-cored welding wire with a diameter of 1.5mm. In this embodiment, the thickness×width of the outer skin of the steel strip is 0.3 mm×10 mm, and the weight of the flux core is 15% of the total weight of the basic flux cored welding wire.

[0054] Example 3

[0055] First, the following components were weighed according to the following ratios: 26wt% barium fluoride, 5wt% lithium fluoride, 2wt% fluorite, 3wt% rutile, 12wt% aluminum powder, 2wt% dead-burned magnesia, 10wt% magnesium powder, 4wt% ferrosilicon, 8wt% manganese metal, 5wt% chromium metal, 13wt% nickel powder, 6wt% ferromolybdenum, and 4wt% atomized iron powder. The aluminum powder, ferrosilicon, manganese metal, chromium metal, nickel powder, ferromolybdenum, and atomized iron powder were then heated at 180°C for 115 minutes. The barium fluoride, lithium fluoride, fluorite, dead-burned magnesia, and magnesium powder were heated at 390°C for 365 minutes, and the rutile was heated at 860°C for 355 minutes. The above components were then mixed and uniformly prepared to produce a flux core. The outer sheath of the steel strip was rolled into a U-shaped groove, and the flux core was filled into the U-shaped groove. The U-shaped groove was closed, and the outer sheath of the flux cored steel strip was drawn and reduced to produce a basic flux-cored welding wire with a diameter of 1.4mm. In this embodiment, the thickness×width of the outer skin of the steel strip is 0.3 mm×10 mm, and the weight of the flux core is 15% of the total weight of the basic flux cored welding wire.

[0056] Example 4

[0057] First, the following components were weighed according to the following ratios: 30wt% barium fluoride, 5wt% lithium fluoride, 2.5wt% fluorite, 3wt% rutile, 11wt% aluminum powder, 2.5wt% dead-burned magnesia, 8wt% magnesium powder, 3wt% ferrosilicon, 6wt% manganese metal, 4wt% chromium metal, 12wt% nickel powder, 8wt% ferromolybdenum, and 5wt% atomized iron powder. The aluminum powder, ferrosilicon, manganese metal, chromium metal, nickel powder, ferromolybdenum, and atomized iron powder were then heated at 170°C for 120 minutes. The barium fluoride, lithium fluoride, fluorite, dead-burned magnesia, and magnesium powder were heated at 400°C for 360 minutes, and the rutile was heated at 850°C for 360 minutes before being mixed and uniformly mixed to produce a flux core. The outer sheath of the steel strip was then rolled into a U-shaped groove, and the flux core was placed into the groove. The U-shaped groove was closed, and the outer sheath of the flux cored steel strip was drawn and reduced to produce a basic flux-cored welding wire with a diameter of 1.6mm. In this embodiment, the thickness×width of the outer skin of the steel strip is 0.3 mm×10 mm, and the weight of the flux core is 16% of the total weight of the basic flux cored welding wire.

[0058] Table 1: Content of core components in basic flux-cored welding wires of Examples 1 to 4

[0059]

[0060] The basic flux-cored wires prepared in Examples 1 to 4 were used to conduct welding tests on high-strength steel. The welding process parameters are shown in Table 2, the chemical composition of the deposited metal is shown in Table 3, and the mechanical properties and welding processability of the deposited metal are shown in Table 4.

[0061] Table 2: Welding process parameters of Examples 1 to 4

[0062]

[0063] Table 3: Chemical composition of deposited metal of basic flux-cored welding wires of Examples 1 to 4

[0064]

[0065] Table 4: Deposited metal properties and welding processability of basic flux-cored welding wires of Examples 1 to 4

[0066]

[0067] As shown in Table 4, the basic flux-cored welding wires prepared in Examples 1 to 4 exhibited excellent mechanical properties, with yield strengths exceeding 780 MPa and tensile strengths exceeding 850 MPa. Furthermore, the basic flux-cored welding wires exhibited excellent mechanical properties, with impact energies exceeding 75 J at -50°C. Furthermore, the basic flux-cored welding wires of the present invention exhibited ultra-low diffusible hydrogen content, effectively reducing the cracking rate of the weld metal and exhibiting high porosity resistance.

[0068] The basic flux-cored welding wire of the present invention produces deposited metal with excellent mechanical properties and low-temperature impact toughness. It also boasts a high deposition rate and deposition rate, good arc stability, minimal spatter, aesthetically pleasing welds, excellent slag removal, and superior welding process performance. It is suitable for welding 830 MPa-grade high-strength steel. Therefore, the present invention effectively overcomes several practical issues in the prior art, resulting in high utilization value and significant practical significance.

[0069] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A basic flux-cored welding wire, characterized in that: The invention comprises a steel strip outer skin and a flux core coated in the steel strip outer skin. The raw material composition of the flux core and the weight percentage of each component are as follows: 20-30wt% of barium fluoride, 5-7wt% of lithium fluoride, 2-3wt% of fluorite, 2-3wt% of rutile, 10-15wt% of aluminum powder, 2-3wt% of dead-burned magnesia, 8-10wt% of magnesium powder, 2-4wt% of ferrosilicon, 6-8wt% of metallic manganese, 3-5wt% of metallic chromium, 12-15wt% of nickel powder, 6-8wt% of ferromolybdenum, and the balance is atomized iron powder.

2. The basic flux-cored welding wire according to claim 1, characterized in that The purity of the barium fluoride is ≥98wt%, the purity of the lithium fluoride is ≥99%, the calcium fluoride content in the fluorite is ≥95wt%, the titanium dioxide content in the rutile is ≥95wt%, the purity of the aluminum powder is ≥97%, the magnesium oxide content in the dead-burned magnesia is ≥90wt%, the purity of the magnesium powder is ≥98%, the silicon content in the ferrosilicon is 42-47wt%, the purity of the metallic manganese is ≥99.8%, the purity of the metallic chromium is ≥99%, the purity of the nickel powder is ≥99%, the molybdenum content in the ferromolybdenum is ≥55wt%, and the purity of the atomized iron powder is ≥98%.

3. The basic flux-cored welding wire according to claim 1, characterized in that The outer skin of the steel strip is made of low-carbon steel strip, and the carbon content of the outer skin of the steel strip is ≤0.01wt%, the silicon content is ≤0.02wt%, the phosphorus content is ≤0.015wt%, the sulfur content is ≤0.015wt%, and the manganese content is 0.10-0.25wt%.

4. The basic flux-cored welding wire according to claim 1, characterized in that The weight of the flux core accounts for 15-17% of the total weight of the basic flux cored welding wire.

5. The basic flux-cored welding wire according to claim 1, characterized in that The diameter of the alkaline flux-cored welding wire is 1.2 mm to 1.6 mm.

6. The basic flux-cored welding wire according to claim 1, characterized in that The deposited metal of the basic flux-cored welding wire has a carbon content of ≤0.15wt%, a manganese content of 1.20-2.25wt%, a silicon content of ≤0.08wt%, a nickel content of 1.75-2.60wt%, a molybdenum content of 0.20-0.65wt%, a phosphorus content of ≤0.03wt%, a sulfur content of ≤0.03wt%, and an aluminum content of ≤1.80wt%.

7. A method for preparing the basic flux-cored welding wire according to any one of claims 1 to 6, characterized in that: The steps include: Weigh each component according to the ratio and mix them evenly to prepare the drug core; Rolling the outer skin of the steel strip into a U-shaped groove, and filling the core into the U-shaped groove and closing it; The outer skin of the steel strip filled with the flux core is drawn and reduced in diameter to a desired specification to obtain the basic flux cored welding wire.

8. The preparation method according to claim 7, characterized in that After weighing each component, the method further includes drying the components. The drying treatment includes: keeping aluminum powder, ferrosilicon, metallic manganese, metallic chromium, nickel powder, ferromolybdenum, and atomized iron powder at 160-180° C. for 115-125 minutes, keeping barium fluoride, lithium fluoride, fluorite, dead-burned magnesia, and magnesium powder at 390-410° C. for 355-365 minutes, and keeping rutile at 840-860° C. for 355-365 minutes.

9. A welding method for a basic flux-cored welding wire according to any one of claims 1 to 6, characterized in that: Welding is performed under the protection of carbon dioxide gas.

10. The welding method according to claim 9, characterized in that: The welding conditions are as follows: the shielding gas is 100% CO2, the shielding gas flow rate is 15-25 L / min, the welding voltage is 25-35 V, and the welding current is 160-350 A.

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