A flux-cored arc welding wire based on C4 steel and its preparation method

Abstract

This invention relates to the field of flux-cored welding wire, specifically to an arc welding flux-cored welding wire based on C4 steel and its preparation method. It addresses the problems of unstable welding quality, insufficient weld joint strength, and poor corrosion resistance often found in existing C4 steel arc welding flux-cored welding wires. This preparation method uses fluorine-doped graphene aerogel as a crucial component of the arc welding flux-cored welding wire. This not only effectively reduces the porosity defect rate and crack probability during welding but also significantly improves the tensile strength and toughness of the welded area. This results in C4 steel parts with superior mechanical properties and corrosion resistance after welding, improving the overall quality of the welded area and consequently enhancing the overall fatigue life and damage resistance of the structure. This arc welding flux-cored welding wire is suitable for various welding processes, meeting the needs of different welding conditions. Furthermore, the process is simple, easy to operate, and suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of flux-cored welding wire, specifically to an arc welding flux-cored welding wire based on C4 steel and its preparation method. Background Technology

[0002] With the development of modern industry, high-strength steel plays an increasingly important role in construction, transportation, energy, and other fields. C4 steel, as a high-strength steel, is widely used in aerospace, petrochemical, and marine engineering. However, due to its high strength and special chemical composition, traditional arc welding flux-cored wire often suffers from unstable welding quality when welding C4 steel, resulting in insufficient weld joint strength and poor corrosion resistance, making it difficult to simultaneously meet the requirements of high strength and good weldability.

[0003] Therefore, developing an arc welding flux-cored wire based on C4 steel and its preparation method is of great significance for improving the welding quality of C4 steel. Summary of the Invention

[0004] To overcome the aforementioned technical problems, the present invention aims to provide an arc welding flux-cored wire based on C4 steel and its preparation method: Micro-carbon ferrochrome, low-carbon ferromanganese, nickel powder, molybdenum powder, fluorine-doped graphene aerogel, titanium dioxide, ferrosilicon, magnesium oxide, yttrium oxide, and iron powder are thoroughly stirred, followed by wet ball milling and drying to obtain welding wire powder. C4 steel strip and E304L steel strip are rolled into a U-shaped steel strip. The welding wire powder is then filled into the U-shaped steel strip, which is then rolled closed to form an O-shaped filler wire. The O-shaped filler wire is then drawn, wound, and packaged to obtain an arc welding flux-cored wire based on C4 steel. This invention solves the problems of unstable welding quality, insufficient weld joint strength, and poor corrosion resistance often found in existing C4 steel arc welding flux-cored wires.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] An arc welding flux-cored wire based on C4 steel, comprising a wire cladding layer and a wire flux powder;

[0007] The welding wire cladding is made of C4 steel strip or E304L steel strip with a thickness of 0.3mm;

[0008] The mass of the welding wire flux is 28% of the mass of the arc welding flux-cored wire based on C4 steel;

[0009] The welding wire powder comprises the following components in parts by weight:

[0010] 35-40 parts of micro-carbon ferrochrome, 8-12 parts of low-carbon ferromanganese, 7.5-11.5 parts of nickel powder, 5-9 parts of molybdenum powder, 2.5-9.5 parts of fluorine-doped graphene aerogel, 4-8 parts of titanium dioxide, 5-13 parts of ferrosilicon, 1-3 parts of magnesium oxide, 1-3 parts of yttrium oxide, and 22-36 parts of iron powder;

[0011] The fluorine-doped graphene aerogel is prepared by the following steps:

[0012] Step s1: Add flake graphite, concentrated sulfuric acid, and sodium nitrate to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at -5 to 0°C for 20 to 30 minutes. Then add potassium permanganate and continue stirring for 1.5 to 2.5 hours. Then raise the temperature to 35 to 40°C and continue stirring for 2 to 3 hours. Then add deionized water and continue stirring for 10 to 12 minutes. Then raise the temperature to 95 to 100°C and continue stirring for 1 to 2 hours. After the reaction is complete, cool the reaction product to room temperature, add hydrogen peroxide solution, let stand for 2 to 3 hours, then centrifuge. Wash the precipitate with distilled water 3 to 5 times, then place it in a vacuum drying oven and dry it at 50 to 55°C for 3 to 5 hours to obtain graphene oxide.

[0013] Step s2: Add graphene oxide and deionized water to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Sonicate the mixture for 40-50 min at an ultrasonic frequency of 35-45 kHz. Then add ascorbic acid and stir the mixture at 0-5℃ and a stirring rate of 300-400 r / min for 3-5 h. Then heat the mixture to reflux and continue stirring for 10-15 h. After the reaction is complete, centrifuge the reaction product and immerse the precipitate in distilled water for 72-96 h. Then freeze dry the precipitate to obtain graphene aerogel.

[0014] Step s3: Add graphene aerogel and hydrofluoric acid to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Stir the reaction at -5 to 0℃ and a stirring rate of 300 to 400 r / min for 20 to 30 min. Then heat to reflux and continue stirring for 20 to 25 h. After the reaction is complete, centrifuge the reaction product and immerse the precipitate in distilled water for 20 to 30 h. Then freeze dry to obtain fluorine-doped graphene aerogel.

[0015] As a further aspect of the present invention: the ratio of the amount of flake graphite, concentrated sulfuric acid, sodium nitrate, potassium permanganate, deionized water and hydrogen peroxide solution used in step s1 is 3g: 80-90mL: 2-3g: 12-16g: 120-150mL: 15-20mL.

[0016] As a further aspect of the present invention: the concentrated sulfuric acid in step s1 has a mass fraction of 98%; the hydrogen peroxide solution has a mass fraction of 30%.

[0017] As a further aspect of the present invention: the ratio of graphene oxide, deionized water and ascorbic acid used in step s2 is 0.1-0.5g: 100-120mL: 0.3-0.9g.

[0018] As a further aspect of the present invention: the ratio of graphene aerogel to hydrofluoric acid in step s3 is 0.1-0.5g:10-12mL.

[0019] As a further aspect of the present invention: the mass fraction of the hydrofluoric acid in step s3 is 10-15%.

[0020] As a further aspect of the present invention: a method for preparing arc welding flux-cored wire based on C4 steel, comprising the following steps:

[0021] Step 1: Weigh out 35-40 parts by weight of micro-carbon ferrochrome, 8-12 parts by weight of low-carbon ferromanganese, 7.5-11.5 parts by weight of nickel powder, 5-9 parts by weight of molybdenum powder, 2.5-9.5 parts by weight of fluorine-doped graphene aerogel, 4-8 parts by weight of titanium dioxide, 5-13 parts by weight of ferrosilicon, 1-3 parts by weight of magnesium oxide, 1-3 parts by weight of yttrium oxide, and 22-36 parts by weight of iron powder, and set aside.

[0022] Step 2: Thoroughly stir micro-carbon ferrochrome, low-carbon ferromanganese, nickel powder, molybdenum powder, fluorine-doped graphene aerogel, titanium dioxide, ferrosilicon, magnesium oxide, yttrium oxide, and iron powder, then wet ball mill, and then place in a vacuum drying oven and dry at a temperature of 130-150℃ for 3-5 hours to obtain welding wire powder.

[0023] Step 3: Roll C4 steel strip and E304L steel strip into U-shaped steel strip. Then fill the U-shaped steel strip with welding wire powder. Roll the U-shaped steel strip to close it and form O-shaped filler wire. Then draw the O-shaped filler wire until the diameter is 1.4mm. Then coil and package it to obtain arc welding flux-cored wire based on C4 steel.

[0024] The beneficial effects of this invention are:

[0025] This invention discloses an arc welding flux-cored wire based on C4 steel and its preparation method. The method involves thoroughly mixing micro-carbon ferrochrome, low-carbon ferromanganese, nickel powder, molybdenum powder, fluorine-doped graphene aerogel, titanium dioxide, ferrosilicon, magnesium oxide, yttrium oxide, and iron powder, followed by wet ball milling and drying to obtain welding wire powder. C4 steel strip and E304L steel strip are rolled into a U-shaped steel strip. The welding wire powder is then filled into the U-shaped steel strip, which is subsequently rolled closed to form an O-shaped filler wire. The O-shaped filler wire is then drawn, coiled, and packaged to obtain the arc welding flux-cored wire based on C4 steel. This preparation method uses fluorine-doped graphene aerogel as an important component of arc welding flux-cored wire. It can not only effectively reduce the porosity defect rate and crack probability during the welding process, but also significantly improve the tensile strength and toughness of the welded area. This results in C4 steel parts with superior mechanical properties and corrosion resistance after welding, improving the overall quality of the welded area and thus enhancing the fatigue life and damage resistance of the overall structure. This arc welding flux-cored wire is suitable for various welding processes, can meet the needs of different welding conditions, and is simple to process, easy to operate, and suitable for large-scale production.

[0026] In the preparation of arc welding flux-cored wire based on C4 steel, a fluorine-doped graphene aerogel was first prepared. Firstly, graphene oxide was prepared using flake graphite as a raw material. Then, using graphene oxide as a raw material, ascorbic acid was added as a reducing agent, and a hydrothermal reaction and freeze-drying method were combined to prepare graphene aerogel. Finally, the graphene aerogel was fluorinated with hydrofluoric acid, introducing a large amount of fluorine into it, resulting in a fluorine-doped graphene aerogel. This fluorine-doped graphene aerogel possesses the advantages of graphene, such as stable properties, high electrical conductivity, good thermal conductivity, and high mechanical strength. Adding it to the arc welding flux-cored wire significantly improves the mechanical strength and high-temperature stability of the wire. Simultaneously, it possesses an extremely high porosity and specific surface area, and its porosity also contributes to the welding process. The flow of the molten pool provides a good channel, promoting slag removal and weld formation. It also undergoes complex physicochemical reactions with the deposited metal, forming a strong metallurgical bond. This not only enhances the density and strength of the deposited metal, improving its toughness and fatigue resistance, but also makes the weld appearance smoother and flatter. After doping with fluorine, fluorine can react with oxygen to generate volatile fluorides, effectively removing oxygen from the weld and preventing oxidation and embrittlement. The remaining fluorine will also form strong chemical bonds with carbon atoms in graphene, forming a physical barrier on the surface of the deposited metal. This barrier hinders the penetration of corrosive media (such as moisture, oxygen, acids, alkalis, etc.) into the interior, reducing their contact with the welding wire metal matrix, thereby slowing down corrosion and significantly improving the corrosion resistance of the flux-cored welding wire. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1:

[0029] This embodiment describes a method for preparing arc welding flux-cored wire based on C4 steel, including the following steps:

[0030] Step S11: Add 3g of flake graphite, 80mL of 98% concentrated sulfuric acid and 2g of sodium nitrate to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at -5℃ and 300r / min for 20min. Then add 12g of potassium permanganate and continue stirring for 1.5h. Then raise the temperature to 35℃ and continue stirring for 2h. Then add 120mL of deionized water and continue stirring for 10min. Then raise the temperature to 95℃ and continue stirring for 1h. After the reaction is complete, cool the reaction product to room temperature. Then add 15mL of 30% hydrogen peroxide solution and let it stand for 2h. Then centrifuge and wash the precipitate three times with distilled water. Then place it in a vacuum drying oven and dry it at 50℃ for 3h to obtain graphene oxide.

[0031] Step S12: Add 0.1g of graphene oxide and 100mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Disperse the mixture ultrasonically at a frequency of 35kHz for 40min. Then add 0.3g of ascorbic acid and stir at 0℃ and a stirring rate of 300r / min for 3h. Then heat to reflux and continue stirring for 10h. After the reaction is complete, centrifuge the reaction product and immerse the precipitate in distilled water for 72h. Then freeze dry to obtain graphene aerogel.

[0032] Step S13: Add 0.1g of graphene aerogel and 10mL of 10% hydrofluoric acid to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Stir the reaction at -5℃ and 300r / min for 20min. Then heat to reflux and continue stirring for 20h. After the reaction is complete, centrifuge the reaction product, immerse the precipitate in distilled water for 20h, and then freeze dry to obtain fluorine-doped graphene aerogel.

[0033] Step S14: Weigh out 35 parts by weight of micro-carbon ferrochrome, 8 parts by weight of low-carbon ferromanganese, 7.5 parts by weight of nickel powder, 5 parts by weight of molybdenum powder, 2.5 parts by weight of fluorine-doped graphene aerogel, 4 parts by weight of titanium dioxide, 5 parts by weight of ferrosilicon, 1 part by weight of magnesium oxide, 1 part by weight of yttrium oxide, and 22 parts by weight of iron powder, and set aside.

[0034] Step S15: Thoroughly stir micro-carbon ferrochrome, low-carbon ferromanganese, nickel powder, molybdenum powder, fluorine-doped graphene aerogel, titanium dioxide, ferrosilicon, magnesium oxide, yttrium oxide and iron powder, then wet ball mill, and then place in a vacuum drying oven and dry at 130℃ for 3 hours to obtain welding wire powder.

[0035] Step S16: Roll C4 steel strip and E304L steel strip to form a U-shaped steel strip. Then fill the U-shaped steel strip with welding wire powder. Roll the U-shaped steel strip to close it and form an O-shaped filler wire. Then draw the O-shaped filler wire until the diameter is 1.4mm. Then coil and package it to obtain an arc welding flux-cored wire based on C4 steel.

[0036] Example 2:

[0037] This embodiment describes a method for preparing arc welding flux-cored wire based on C4 steel, including the following steps:

[0038] Step S21: Add 3g of flake graphite, 85mL of 98% concentrated sulfuric acid and 2.5g of sodium nitrate to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at -3℃ and 350r / min for 25min. Then add 14g of potassium permanganate and continue stirring for 2h. Then raise the temperature to 38℃ and continue stirring for 2.5h. Then add 135mL of deionized water and continue stirring for 11min. Then raise the temperature to 98℃ and continue stirring for 1.5h. After the reaction is complete, cool the reaction product to room temperature, then add 18mL of 30% hydrogen peroxide solution. Let it stand for 2.5h, then centrifuge. Wash the precipitate four times with distilled water. Then place it in a vacuum drying oven and dry it at 52℃ for 4h to obtain graphene oxide.

[0039] Step S22: Add 0.3g of graphene oxide and 110mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Disperse the mixture ultrasonically at a frequency of 40kHz for 45min. Then add 0.6g of ascorbic acid and stir at 3℃ and a stirring rate of 350r / min for 4h. Then raise the temperature to reflux and continue stirring for 12h. After the reaction is completed, centrifuge the reaction product and immerse the precipitate in distilled water for 84h. Then freeze dry to obtain graphene aerogel.

[0040] Step S23: Add 0.3g of graphene aerogel and 11mL of 12% hydrofluoric acid to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Stir the reaction at -3℃ and 350r / min for 25min. Then heat to reflux and continue stirring for 22h. After the reaction is completed, centrifuge the reaction product, immerse the precipitate in distilled water for 25h, and then freeze dry to obtain fluorine-doped graphene aerogel.

[0041] Step S24: Weigh out 38 parts by weight of micro-carbon ferrochrome, 10 parts by weight of low-carbon ferromanganese, 9.5 parts by weight of nickel powder, 7 parts by weight of molybdenum powder, 6 parts by weight of fluorine-doped graphene aerogel, 6 parts by weight of titanium dioxide, 9 parts by weight of ferrosilicon, 2 parts by weight of magnesium oxide, 2 parts by weight of yttrium oxide, and 29 parts by weight of iron powder, and set aside.

[0042] Step S25: Micro-carbon ferrochrome, low-carbon ferromanganese, nickel powder, molybdenum powder, fluorine-doped graphene aerogel, titanium dioxide, ferrosilicon, magnesium oxide, yttrium oxide and iron powder are thoroughly stirred, then wet-milled, and then placed in a vacuum drying oven and dried at 140℃ for 4 hours to obtain welding wire powder.

[0043] Step S26: Roll C4 steel strip and E304L steel strip to form a U-shaped steel strip. Then fill the U-shaped steel strip with welding wire powder. Roll the U-shaped steel strip to close it and form an O-shaped filler wire. Then draw the O-shaped filler wire until the diameter is 1.4mm. Then coil and package it to obtain an arc welding flux-cored wire based on C4 steel.

[0044] Example 3:

[0045] This embodiment describes a method for preparing arc welding flux-cored wire based on C4 steel, including the following steps:

[0046] Step S31: Add 3g of flake graphite, 90mL of 98% concentrated sulfuric acid and 3g of sodium nitrate to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 0℃ and 400r / min for 30min. Then add 16g of potassium permanganate and continue stirring for 2.5h. Then raise the temperature to 40℃ and continue stirring for 3h. Then add 150mL of deionized water and continue stirring for 12min. Then raise the temperature to 100℃ and continue stirring for 2h. After the reaction is complete, cool the reaction product to room temperature. Then add 20mL of 30% hydrogen peroxide solution and let it stand for 3h. Then centrifuge and wash the precipitate with distilled water five times. Then place it in a vacuum drying oven and dry it at 55℃ for 5h to obtain graphene oxide.

[0047] Step S32: Add 0.5g of graphene oxide and 120mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Disperse the mixture ultrasonically at a frequency of 45kHz for 50min. Then add 0.9g of ascorbic acid and stir at 5℃ and a stirring rate of 400r / min for 5h. Then heat to reflux and continue stirring for 15h. After the reaction is complete, centrifuge the reaction product and immerse the precipitate in distilled water for 96h. Then freeze dry to obtain graphene aerogel.

[0048] Step S33: Add 0.5g of graphene aerogel and 12mL of 15% hydrofluoric acid to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Stir the reaction at 0℃ and 400r / min for 30min. Then heat to reflux and continue stirring for 25h. After the reaction is complete, centrifuge the reaction product, immerse the precipitate in distilled water for 30h, and then freeze dry to obtain fluorine-doped graphene aerogel.

[0049] Step S34: Weigh out 40 parts by weight of micro-carbon ferrochrome, 12 parts by weight of low-carbon ferromanganese, 11.5 parts by weight of nickel powder, 9 parts by weight of molybdenum powder, 9.5 parts by weight of fluorine-doped graphene aerogel, 8 parts by weight of titanium dioxide, 13 parts by weight of ferrosilicon, 3 parts by weight of magnesium oxide, 3 parts by weight of yttrium oxide, and 36 parts by weight of iron powder, and set aside.

[0050] Step S35: Micro-carbon ferrochrome, low-carbon ferromanganese, nickel powder, molybdenum powder, fluorine-doped graphene aerogel, titanium dioxide, ferrosilicon, magnesium oxide, yttrium oxide and iron powder are thoroughly stirred, then wet-milled, and then placed in a vacuum drying oven and dried at 150°C for 5 hours to obtain welding wire powder.

[0051] Step S36: Roll C4 steel strip and E304L steel strip to form a U-shaped steel strip. Then fill the U-shaped steel strip with welding wire powder. Roll the U-shaped steel strip to close it and form an O-shaped filler wire. Then draw the O-shaped filler wire until the diameter is 1.4mm. Then coil and package it to obtain an arc welding flux-cored wire based on C4 steel.

[0052] Comparative Example 1:

[0053] This comparative example illustrates a method for preparing arc welding flux-cored wire based on C4 steel, comprising the following steps:

[0054] Step D11: Weigh out 40 parts by weight of micro-carbon ferrochrome, 12 parts by weight of low-carbon ferromanganese, 11.5 parts by weight of nickel powder, 9 parts by weight of molybdenum powder, 8 parts by weight of titanium dioxide, 13 parts by weight of ferrosilicon, 3 parts by weight of magnesium oxide, 3 parts by weight of yttrium oxide, and 36 parts by weight of iron powder, and set aside.

[0055] Step D12: Thoroughly stir micro-carbon ferrochrome, low-carbon ferromanganese, nickel powder, molybdenum powder, titanium dioxide, ferrosilicon, magnesium oxide, yttrium oxide and iron powder, then wet ball mill, and then place in a vacuum drying oven and dry at 150℃ for 5 hours to obtain welding wire powder.

[0056] Step D13: Roll C4 steel strip and E304L steel strip to form a U-shaped steel strip. Then fill the U-shaped steel strip with welding wire powder. Roll the U-shaped steel strip to close it and form an O-shaped filler wire. Then draw the O-shaped filler wire until the diameter is 1.4mm. Then coil and package it to obtain an arc welding flux-cored wire based on C4 steel.

[0057] Comparative Example 2:

[0058] This comparative example illustrates a method for preparing arc welding flux-cored wire based on C4 steel, comprising the following steps:

[0059] Step D21: Add 3g of flake graphite, 90mL of 98% concentrated sulfuric acid and 3g of sodium nitrate to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 0℃ and 400r / min for 30min. Then add 16g of potassium permanganate and continue stirring for 2.5h. Then raise the temperature to 40℃ and continue stirring for 3h. Then add 150mL of deionized water and continue stirring for 12min. Then raise the temperature to 100℃ and continue stirring for 2h. After the reaction is complete, cool the reaction product to room temperature, then add 20mL of 30% hydrogen peroxide solution. Let it stand for 3h, then centrifuge. Wash the precipitate five times with distilled water. Then place it in a vacuum drying oven and dry it at 55℃ for 5h to obtain graphene oxide.

[0060] Step D22: Weigh out 40 parts by weight of micro-carbon ferrochrome, 12 parts by weight of low-carbon ferromanganese, 11.5 parts by weight of nickel powder, 9 parts by weight of molybdenum powder, 9.5 parts by weight of graphene oxide, 8 parts by weight of titanium dioxide, 13 parts by weight of ferrosilicon, 3 parts by weight of magnesium oxide, 3 parts by weight of yttrium oxide, and 36 parts by weight of iron powder, and set aside.

[0061] Step D23: Thoroughly stir micro-carbon ferrochrome, low-carbon ferromanganese, nickel powder, molybdenum powder, graphene oxide, titanium dioxide, ferrosilicon, magnesium oxide, yttrium oxide, and iron powder, then wet ball mill, and then place in a vacuum drying oven and dry at 150℃ for 5 hours to obtain welding wire powder.

[0062] Step D24: Roll C4 steel strip and E304L steel strip to form a U-shaped steel strip. Then fill the U-shaped steel strip with welding wire powder. Roll the U-shaped steel strip to close it and form an O-shaped filler wire. Then draw the O-shaped filler wire until the diameter is 1.4mm. Then coil and package it to obtain an arc welding flux-cored wire based on C4 steel.

[0063] Comparative Example 3:

[0064] This comparative example illustrates a method for preparing arc welding flux-cored wire based on C4 steel, comprising the following steps:

[0065] Step D31: Add 3g of flake graphite, 90mL of 98% concentrated sulfuric acid and 3g of sodium nitrate to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at 0℃ and 400r / min for 30min. Then add 16g of potassium permanganate and continue stirring for 2.5h. Then raise the temperature to 40℃ and continue stirring for 3h. Then add 150mL of deionized water and continue stirring for 12min. Then raise the temperature to 100℃ and continue stirring for 2h. After the reaction is complete, cool the reaction product to room temperature, then add 20mL of 30% hydrogen peroxide solution. Let it stand for 3h, then centrifuge. Wash the precipitate five times with distilled water. Then place it in a vacuum drying oven and dry it at 55℃ for 5h to obtain graphene oxide.

[0066] Step D32: Add 0.5g of graphene oxide and 120mL of deionized water to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Sonicate the mixture for 50min at an ultrasonic frequency of 45kHz. Then add 0.9g of ascorbic acid and stir for 5h at a temperature of 5℃ and a stirring rate of 400r / min. Then heat to reflux and continue stirring for 15h. After the reaction is complete, centrifuge the reaction product and immerse the precipitate in distilled water for 96h. Then freeze dry to obtain graphene aerogel.

[0067] Step D33: Weigh out 40 parts by weight of micro-carbon ferrochrome, 12 parts by weight of low-carbon ferromanganese, 11.5 parts by weight of nickel powder, 9 parts by weight of molybdenum powder, 9.5 parts by weight of graphene aerogel, 8 parts by weight of titanium dioxide, 13 parts by weight of ferrosilicon, 3 parts by weight of magnesium oxide, 3 parts by weight of yttrium oxide, and 36 parts by weight of iron powder, and set aside.

[0068] Step D34: Thoroughly stir micro-carbon ferrochrome, low-carbon ferromanganese, nickel powder, molybdenum powder, graphene aerogel, titanium dioxide, ferrosilicon, magnesium oxide, yttrium oxide, and iron powder, then wet ball mill, and then place in a vacuum drying oven and dry at 150℃ for 5 hours to obtain welding wire powder.

[0069] Step D35: Roll C4 steel strip and E304L steel strip to form a U-shaped steel strip. Then fill the U-shaped steel strip with welding wire powder. Roll the U-shaped steel strip to close it and form an O-shaped filler wire. Then draw the O-shaped filler wire until the diameter is 1.4mm. Then coil and package it to obtain an arc welding flux-cored wire based on C4 steel.

[0070] The flux-cored arc welding wires based on C4 steel used in Examples 1-3 and Comparative Examples 1-3 were subjected to surfacing experiments using C4 steel plates as the base material. The welding parameters were: welding current 190A, arc voltage 28V, welding speed 10m / h, and nitrogen-argon mixed gas with a flow rate of 1-1.5L / min. The properties of the deposited metal were then tested, and the results are shown in the table below.

[0071]

[0072] Referring to the data in the table above, and based on the comparison between Examples 1-3 and Comparative Examples 1-3, it can be seen that the addition of fluorine-doped graphene aerogel significantly improves the nitric acid corrosion resistance and mechanical properties of arc welding flux-cored wires based on C4 steel.

[0073] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0074] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. An arc welding flux-cored wire based on C4 steel, characterized in that, Including the welding wire coating and the welding wire flux; The welding wire cladding is made of E304L steel strip with a thickness of 0.3mm; The mass of the welding wire flux is 28% of the mass of the arc welding flux-cored wire based on C4 steel; The welding wire powder comprises the following components in parts by weight: 35-40 parts of micro-carbon ferrochrome, 8-12 parts of low-carbon ferromanganese, 7.5-11.5 parts of nickel powder, 5-9 parts of molybdenum powder, 2.5-9.5 parts of fluorine-doped graphene aerogel, 4-8 parts of titanium dioxide, 5-13 parts of ferrosilicon, 1-3 parts of magnesium oxide, 1-3 parts of yttrium oxide, and 22-36 parts of iron powder; The fluorine-doped graphene aerogel is prepared by the following steps: Step s1: Add flake graphite, concentrated sulfuric acid, and sodium nitrate to a three-necked flask equipped with a stirrer and thermometer. Stir the reaction at -5 to 0°C for 20 to 30 minutes. Then add potassium permanganate and continue stirring for 1.5 to 2.5 hours. Then raise the temperature to 35 to 40°C and continue stirring for 2 to 3 hours. Then add deionized water and continue stirring for 10 to 12 minutes. Then raise the temperature to 95 to 100°C and continue stirring for 1 to 2 hours. After the reaction is complete, cool the reaction product to room temperature, add hydrogen peroxide solution, let stand for 2 to 3 hours, then centrifuge. Wash the precipitate with distilled water 3 to 5 times, then place it in a vacuum drying oven and dry it at 50 to 55°C for 3 to 5 hours to obtain graphene oxide. Step s2: Add graphene oxide and deionized water to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Sonicate the mixture for 40-50 min at an ultrasonic frequency of 35-45 kHz. Then add ascorbic acid and stir the mixture at 0-5℃ and a stirring rate of 300-400 r / min for 3-5 h. Then heat the mixture to reflux and continue stirring for 10-15 h. After the reaction is complete, centrifuge the reaction product and immerse the precipitate in distilled water for 72-96 h. Then freeze dry the precipitate to obtain graphene aerogel. Step s3: Add graphene aerogel and hydrofluoric acid to a three-necked flask equipped with a stirrer, thermometer and reflux condenser. Stir the reaction at -5 to 0℃ and a stirring rate of 300 to 400 r / min for 20 to 30 min. Then heat to reflux and continue stirring for 20 to 25 h. After the reaction is complete, centrifuge the reaction product and immerse the precipitate in distilled water for 20 to 30 h. Then freeze dry to obtain fluorine-doped graphene aerogel.

2. The flux-cored welding wire for arc welding based on C4 steel according to claim 1, characterized in that, The ratio of flake graphite, concentrated sulfuric acid, sodium nitrate, potassium permanganate, deionized water and hydrogen peroxide solution used in step s1 is 3g: 80-90mL: 2-3g: 12-16g: 120-150mL: 15-20mL.

3. The arc welding flux-cored wire based on C4 steel according to claim 1, characterized in that, The concentrated sulfuric acid in step s1 has a mass fraction of 98%; the hydrogen peroxide solution has a mass fraction of 30%.

4. The flux-cored arc welding wire based on C4 steel according to claim 1, characterized in that, The ratio of graphene oxide, deionized water, and ascorbic acid used in step s2 is 0.1-0.5g: 100-120mL: 0.3-0.9g.

5. The arc welding flux-cored wire based on C4 steel according to claim 1, characterized in that, In step s3, the ratio of graphene aerogel to hydrofluoric acid is 0.1-0.5g:10-12mL.

6. The flux-cored arc welding wire based on C4 steel according to claim 1, characterized in that, The mass fraction of the hydrofluoric acid in step s3 is 10-15%.

7. A method for preparing an arc welding flux-cored wire based on C4 steel as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Weigh out 35-40 parts by weight of micro-carbon ferrochrome, 8-12 parts by weight of low-carbon ferromanganese, 7.5-11.5 parts by weight of nickel powder, 5-9 parts by weight of molybdenum powder, 2.5-9.5 parts by weight of fluorine-doped graphene aerogel, 4-8 parts by weight of titanium dioxide, 5-13 parts by weight of ferrosilicon, 1-3 parts by weight of magnesium oxide, 1-3 parts by weight of yttrium oxide, and 22-36 parts by weight of iron powder, and set aside. Step 2: Thoroughly stir micro-carbon ferrochrome, low-carbon ferromanganese, nickel powder, molybdenum powder, fluorine-doped graphene aerogel, titanium dioxide, ferrosilicon, magnesium oxide, yttrium oxide, and iron powder, then wet ball mill, and then place in a vacuum drying oven and dry at a temperature of 130-150℃ for 3-5 hours to obtain welding wire powder. Step 3: Roll the E304L steel strip to form a U-shaped steel strip. Then fill the U-shaped steel strip with welding wire powder. Roll the U-shaped steel strip to close it and form an O-shaped filler wire. Then draw the O-shaped filler wire until the diameter is 1.4mm. Finally, coil and package it to obtain the arc welding flux-cored wire based on C4 steel.

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