Hydrogen-resistant flux-cored wire for small hydrogen storage tank and preparation method and cladding method of hydrogen-resistant flux-cored wire

Abstract

The invention discloses an anti-hydrogen flux-cored wire for a small hydrogen storage tank and a preparation method and a cladding method of the anti-hydrogen flux-cored wire, the anti-hydrogen flux-cored wire for the small hydrogen storage tank comprises a flux core and a welding skin, the flux core is composed of, by mass, 40%-60% of Ni powder, 17.0%-21.0% of Cr powder, 15%-19% of Fe powder, 4.75%-7.45% of Nb powder, 2.8%-4.3% of Mo powder, 5.0%-15.0% of CeO2 powder and 0.02%-0.10% of C powder, and the sum of the mass percentages of the components is 100%. By adjusting the flux core components and optimizing the cladding process, different hydrogen storage tank body materials and welding requirements are met, the problem that in the prior art, the hydrogen permeation resistance is poor is solved, the toughness of the flux-cored wire on a cladding layer of a hydrogen storage tank body is improved, a thinner cladding layer is coated, the surface smoothness is better, and the welding quality is improved. The overall performance and the service life of the hydrogen storage tank body are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal materials, and relates to a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank. The invention also relates to a preparation method and a cladding method of the flux-cored welding wire. Background Art

[0002] With the transformation of the global energy structure, traditional fossil fuels are gradually being replaced by clean energy. Hydrogen energy has become an important research direction in the energy field due to its high energy density, clean combustion products (only water is produced) and renewability. Small hydrogen storage tanks came into being in this context and became one of the key technologies for hydrogen energy storage and utilization.

[0003] Small hydrogen storage tanks have broad application prospects in many fields. Hydrogen fuel cell vehicles (such as hydrogen fuel cell passenger cars, trucks and buses) require small, lightweight hydrogen storage tanks to store hydrogen to meet the fuel needs of the vehicle. Small hydrogen storage tanks can provide clean energy support for portable devices (such as portable generators, drones, etc.). In distributed energy systems, small hydrogen storage tanks can be used to store excess hydrogen produced by electrolysis of water, balance the load of the power grid, and improve energy efficiency.

[0004] The cladding material of a small hydrogen storage tank needs to have high strength, excellent toughness and outstanding hydrogen permeation resistance to cope with the complex tests of high pressure, low temperature and long-term exposure to hydrogen environment. The hydrogen permeation resistance of the cladding material can prevent hydrogen from penetrating into the tank material, thereby avoiding safety hazards such as hydrogen-induced cracking and hydrogen embrittlement, and ensuring the long-term safe operation of the hydrogen storage tank. However, traditional cladding materials have certain limitations in hydrogen permeation resistance, and it is difficult to meet the high performance requirements of small hydrogen storage tanks in extreme hydrogen environments. In view of the shortcomings of traditional cladding materials in hydrogen permeation resistance, it is particularly important to develop a hydrogen storage tank cladding material with excellent hydrogen permeation resistance. Summary of the invention

[0005] The first object of the present invention is to provide a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank, which solves the problem of poor hydrogen permeation resistance in the prior art.

[0006] The second object of the present invention is to provide a method for preparing the above-mentioned hydrogen-resistant flux-cored welding wire for small hydrogen storage tanks.

[0007] The third object of the present invention is to provide a cladding method for the above-mentioned hydrogen-resistant flux-cored welding wire for the small hydrogen storage tank.

[0008] The technical solution adopted by the present invention is that the hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank comprises a flux core and a welding skin, and the flux core is composed of the following components by mass percentage: Ni powder 40%~60%, Cr powder 17.0%~21.0%, Fe powder 15%~19%, Nb powder 4.75%~7.45%, Mo powder 2.8%~4.3%, CeO2 powder 5.0%~15.0%, C powder 0.02%~0.10%. The sum of the mass percentages of the above components is 100%.

[0009] The present invention is also characterized in that: The particle size of the core powder is 15~45µm; The welding skin is a nickel-based alloy strip with a thickness of 0.2 mm and a width of 7 mm; The filling rate of the flux core in the welding skin is 18%-25%.

[0010] The second technical solution adopted by the present invention is a method for preparing a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank, which is specifically implemented according to the following steps: Step 1: Weigh the following powders by mass percentage: Ni powder: 40%~60%, Cr powder: 17.0%~21.0%, Fe powder: 15%~19%, Nb powder: 4.75%~7.45%, Mo powder: 2.8%~4.3%, CeO2 powder: 5.0%~15.0%, C powder: 0.02%~0.10%, the sum of the mass percentages of the above components is 100%; Step 2: placing the powder weighed in step 1 into a ball mill, grinding the powder to fully mix the powders of each component and improve the original shape of the metal powder; Step 3, filling the powder prepared in step 2 into the U-shaped welding skin, and closing the welding skin with a mold to obtain the original welding wire; Step 4: The original welding wire is made into a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body with a set diameter by a step-by-step diameter reduction method, and impurities on the surface of the welding wire are removed.

[0011] The second technical solution of the present invention is also characterized in that: In step 2, stainless steel ball milling beads are used in the ball milling jar, the diameter of the ball milling beads is 5 mm, 10 mm, and 20 mm, the ball milling speed reaches 200-300 r / min, and the ball milling time is 2-3 hours; the powder particle size is 15-45 μm; In step 3, the welding skin is a nickel-based alloy strip with a thickness of 0.2 mm and a width of 7 mm; In step 3, the filling rate of the flux core powder in the welding skin is controlled at 18%~25%.

[0012] The third technical solution adopted by the present invention is a cladding method of a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body, which uses the above-mentioned hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body for laser cladding, and is specifically implemented in the following steps: S1. Set the laser welding equipment parameters: laser power 350~400W, laser energy density range 50~200J / mm 3 , scanning speed is 400~500mm / s; S2, select the above-mentioned small hydrogen storage tank body and load the hydrogen-resistant flux-cored welding wire into the wire feeding mechanism, set the required wire feeding speed, and continuously introduce the protective gas; S3. Fix the workpiece on the workbench, start the laser equipment and wire feeding mechanism, and perform laser cladding operation according to the preset scanning path and process parameters in a protective gas environment to obtain a cladding layer.

[0013] The third technical solution of the present invention is also characterized in that: The shielding gas described in S2 is Ar with a volume fraction of 99%, and the flow rate of the shielding gas is 13~16L / min.

[0014] The beneficial effects of the present invention are: The hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body of the present invention, as well as its preparation method and cladding method, adapt to different hydrogen storage tank body materials and welding requirements by adjusting the flux core components and optimizing the cladding process, solve the problem of poor hydrogen permeation resistance in the prior art, improve the toughness of the flux-cored welding wire in the cladding layer of the hydrogen storage tank body, better control the layer thickness, apply a thinner coating and better surface finish, thereby improving the overall performance and service life of the hydrogen storage tank body. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a microstructure diagram of the cladding layer obtained by laser cladding of the existing flux-cored welding wire in Example 1; Figure 2 This is a microstructure diagram of the cladding layer prepared by the hydrogen-resistant flux-cored welding wire for the small hydrogen storage tank of the present invention in Example 2; Figure 3 This is a microstructure diagram of the cladding layer prepared by the hydrogen-resistant flux-cored welding wire for the small hydrogen storage tank of the present invention in Example 3; Figure 4 This is a microstructure diagram of the cladding layer prepared by the hydrogen-resistant flux-cored welding wire for the small hydrogen storage tank body of the present invention in Example 4. DETAILED DESCRIPTION

[0016] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] The hydrogen-resistant flux-cored welding wire for small hydrogen storage tanks includes a flux core and a welding cover. The flux core is composed of the following components by mass percentage: Ni powder: 40%~60%, Cr powder: 17.0%~21.0%, Fe powder: 15%~19%, Nb powder: 4.75%~7.45%, Mo powder: 2.8%~4.3%, CeO2 powder: 5.0%~15.0%, C powder: 0.02%~0.10%, the sum of the mass percentages of the above components is 100%; The powder particle size of the drug powder in the drug core is 15~45µm; The welding skin is nickel-based alloy strip; thickness 0.2mm, width 7mm; The filling rate of the flux core in the welding skin is 18%~25%.

[0018] The functions of each component in the welding wire core are as follows: C: There is a synergistic effect between carbon and other alloying elements (such as manganese, silicon, chromium, nickel, etc.). The combined effect of these elements helps to reduce the hydrogen concentration in the weld and slow down the diffusion rate of hydrogen, thereby significantly enhancing the hydrogen resistance of the weld.

[0019] Ni: Nickel provides the alloy's basic structure and corrosion resistance. Nickel can resist the erosion of hydrogen and prevent hydrogen atoms from penetrating into the alloy, thereby reducing the risk of hydrogen embrittlement.

[0020] Cr: Chromium is a strong oxidant that can form a dense oxide film on the surface of the alloy to prevent further erosion by hydrogen. This oxide film has high stability and corrosion resistance and can effectively protect the alloy from hydrogen embrittlement.

[0021] Mo: Molybdenum can improve the strength and hardness of the alloy, and also enhance the corrosion resistance of the alloy. In terms of hydrogen resistance, molybdenum can combine with hydrogen atoms to form stable compounds, thereby reducing the diffusion and aggregation of hydrogen atoms in the alloy.

[0022] Nb: Niobium can combine with carbon to form stable carbides, thereby improving the high-temperature strength and corrosion resistance of the alloy. In terms of hydrogen resistance, niobium can also combine with hydrogen atoms to reduce the diffusion and aggregation of hydrogen atoms in the alloy.

[0023] CeO2: Cerium oxide has unique redox properties. 3+ and Ce 4+ The redox cycle of CeO2 can mimic the activity of enzymes such as superoxide dismutase (SOD) and catalase (CAT). In the process of hydrogen resistance, this redox property may help to scavenge free radicals and alleviate oxidative stress. In some studies, the oxygen storage capacity of CeO2 can be enhanced by doping with other rare earth ions. This oxygen storage capacity may play a role in the process of hydrogen resistance, such as affecting hydrogen adsorption and reaction by regulating the local oxygen concentration.

[0024] Fe: Iron works together with other alloying elements (such as chromium, molybdenum, etc.) to form stable compounds, which prevent the diffusion of hydrogen atoms and improve the material's resistance to hydrogen embrittlement.

[0025] The present invention also provides a method for preparing a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank, which is specifically implemented by the following steps: Step 1: Weigh the following powders by mass percentage: Ni powder 40%~60%, Cr powder 17.0%~21.0%, Fe powder 15%~19%, Nb powder 4.75%~7.45%, Mo powder 2.8%~4.3%, CeO2 powder 5.0%~15.0%, C powder 0.02%~0.10%. The sum of the mass percentages of the above components is 100%.

[0026] Step 2: Place the powder weighed in step 1 in a ball mill, grind the powder to fully mix the powders of each component, and improve the original shape of the metal powder.

[0027] Stainless steel ball milling beads are used in the ball milling tank. The diameter of the ball milling beads is 5mm, 10mm, and 20mm. The ball milling speed reaches 200~300r / min, and the ball milling time is 2~3 hours; Powder particle size is 15~45µm; The alloy powders of each component can be directly purchased as finished products that meet the particle size requirements, or the alloy powders with larger particle sizes can be processed through conventional pretreatment methods to achieve the required powder particle size requirements.

[0028] The ball mill is a planetary ball mill; The grinding process in the ball mill can fully mix the components of the powder. The movement of the grinding balls constantly turns and stirs the powder, so that the powders of different components can be evenly distributed, thus ensuring the uniformity of the components of the mixed powder. The original shape of metal powder may be irregular. During the ball milling process, the powder particles constantly collide and rub against the grinding balls and the inner wall of the ball mill, and their edges and corners will gradually be worn away, making the particle shape more spherical or quasi-spherical; this regularly shaped powder has better performance in terms of fluidity and filling properties.

[0029] Step 3, filling the powder prepared in step 2 into the U-shaped welding skin, and closing the welding skin with a mold to obtain the original welding wire; The welding skin is a nickel-based alloy strip with a thickness of 0.2 mm and a width of 7 mm; The filling rate of the flux core powder in the welding skin is 18%-25%.

[0030] Step 4: The original welding wire is made into a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body with a set diameter by a step-by-step diameter reduction method, and impurities on the surface of the welding wire are removed.

[0031] The present invention also provides a cladding method for a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank, which is specifically implemented by the following steps: S1. Set laser welding equipment parameters: Laser power 350~400W, laser energy density range 50~200J / mm 3 , the scanning speed is 400~500mm / s.

[0032] S2, select the above-mentioned small hydrogen storage tank body and load the hydrogen-resistant flux-cored welding wire into the wire feeding mechanism, set the wire feeding speed, and continuously introduce the protective gas; The wire diameter is 1.6mm, and the wire feeding speed is 1.2m / min~1.6m / min; The shielding gas during the cladding process is Ar with a volume fraction of 99%, and the flow rate of the shielding gas is 13~16L / min; the shielding gas can effectively prevent the molten metal from splashing and pores.

[0033] S3. Fix the workpiece on the workbench, start the laser equipment and wire feeding mechanism, and perform laser cladding operation according to the preset scanning path and process parameters under a protective gas environment to obtain a cladding layer.

[0034] According to the above steps, the above-mentioned small hydrogen storage tank body is clad with the hydrogen-resistant flux-cored welding wire on the inner surface of the hydrogen storage tank body, and the cladding layer metal is prepared by surfacing welding on the inner surface of the hydrogen storage tank body. By optimizing the cladding process parameters and adjusting the composition of the cladding layer, the density and hydrogen penetration resistance of the cladding layer can be effectively improved. The laser cladding layer has a high bonding strength with the substrate, which can provide a good metallurgical bond and improve the stability and reliability of the cladding layer during use.

[0035] Example 1 This embodiment is a comparative example of the present invention. Conventional metal flux-cored welding wire is used to perform laser cladding on the inside of a hydrogen storage tank. The specific steps are as follows: Step 1, preparing a metal flux-cored welding wire; The flux core components are: Ni powder 48.3%, Cr powder 21.0%, Fe powder 19.0%, Nb powder 7.4%, Mo powder 4.2%, C powder 0.10%, the sum of the above raw material contents is 100%; the powder particle size is 15~45µm; the filling rate of the flux core powder in the welding skin is 23%; the welding wire diameter is 1.6mm.

[0036] Step 2: using the welding wire prepared in step 1 to perform laser cladding on the hydrogen storage tank body; The laser power is 350W and the laser energy density is 50J / mm 3 , the scanning speed is 300mm / s; during the cladding process, 99% Ar gas by volume is used to protect the welding area, and the flow rate of the protective gas is 15.1L / min.

[0037] like Figure 1 As shown in the figure, the obtained cladding layer is uniform and continuous, with no pores or slag inclusions on the surface. The test results of the cladding layer show that after mechanical property testing and microstructure observation, the average microhardness can reach 380.8HV. 0.5 , the hydrogen diffusion coefficient is 2.37×10 -6 cm 2 / s, the hydrogen diffusion coefficient is smaller than that of the hydrogen storage tank base material (the hydrogen diffusion coefficient is 2.74×10 -6 cm 2 / s), indicating that the hydrogen resistance of the nickel-based cladding layer is improved by laser cladding.

[0038] Example 2 In this embodiment, a small hydrogen storage tank body is used to prepare a cladding layer using a hydrogen-resistant flux-cored welding wire, which is specifically implemented in the following steps: Step 1, preparing a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank; Step 1-1, weigh the following powders by mass percentage: Ni: 55.15%, Cr: 17.0%, Fe: 15.0%, Nb: 4.8%, Mo: 3.0%, CeO2: 5.0%, C: 0.05%, the sum of the above raw material contents is 100%; Step 1-2, placing the powder weighed in step 1 in a ball mill, grinding the powder to fully mix the powder components and improve the original shape of the metal powder; stainless steel ball mills are used in the ball mill, the ball mill diameters are 5 mm, 10 mm, and 20 mm, the ball mill speed reaches 200 r / min, and the ball milling time is 2 hours; the powder particle size is 15~45 μm; Step 1-3, filling the powder prepared in step 2 into a U-shaped welding skin, and closing the welding skin with a mold to obtain an original welding wire; the filling rate of the core powder in the welding skin is 18%-25%; Step 1-4, the original welding wire is made into a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body with a set diameter by a step-by-step diameter reduction method, and impurities on the surface of the welding wire are removed; the diameter of the welding wire is 1.6 mm.

[0039] Step 2: using the welding wire prepared in step 1 to perform laser cladding on the hydrogen storage tank body; The laser power is 350W and the laser energy density is 100J / mm 3 , the scanning speed is 400mm / s; during the cladding process, 99% Ar gas by volume is used to protect the welding area, and the flow rate of the protective gas is 15.1L / min.

[0040] The prepared welding wire was subjected to multiple cladding experiments, such as Figure 2As shown in the figure, the obtained cladding layer is uniform and continuous, with no pores or slag inclusions on the surface. The test results of the cladding layer show that after mechanical property testing and microstructure observation, the average microhardness can reach 380.8HV. 0.5 , the hydrogen diffusion coefficient is 2.15×10 -6 cm 2 / s, the hydrogen diffusion coefficient is smaller than that of the hydrogen storage tank base material (the hydrogen diffusion coefficient is 2.74×10 -6 cm 2 / s), indicating that the hydrogen resistance of the cladding layer obtained by laser cladding the small hydrogen storage tank body with the hydrogen-resistant flux-cored welding wire in the present invention is improved.

[0041] Example 3 In this embodiment, a small hydrogen storage tank body is used to prepare a cladding layer using a hydrogen-resistant flux-cored welding wire, which is specifically implemented in the following steps: Step 1, preparing a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank; Step 1-1, weigh the following powders by mass percentage: Ni: 46.22%, Cr: 21.0%, Fe: 17.0%, Nb: 5.2%, Mo: 5.30%, CeO2: 10.0%, C: 0.08%, the sum of the above raw material contents is 100%; Step 1-2, placing the powder weighed in step 1 in a ball mill, grinding the powder to fully mix the powder components and improve the original shape of the metal powder; stainless steel ball milling beads are selected in the ball mill, the ball milling beads have a diameter of 5mm, 10mm, and 20mm, the ball milling speed reaches 200-300r / min, and the ball milling time is 2-3 hours; the powder particle size is 15-45µm; Step 1-3, filling the powder prepared in step 2 into a U-shaped welding skin, and closing the welding skin with a mold to obtain an original welding wire; the filling rate of the core powder in the welding skin is 18%-25%; Step 1-4, the original welding wire is made into a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body with a set diameter by a step-by-step diameter reduction method, and impurities on the surface of the welding wire are removed; the diameter of the welding wire is 1.6 mm.

[0042] Step 2: using the welding wire prepared in step 1 to perform laser cladding on the hydrogen storage tank body; The laser power is 350W and the laser energy density is 150J / mm 3 , the scanning speed is 500mm / s; during the cladding process, 99% Ar gas by volume is used to protect the welding area, and the flow rate of the protective gas is 15.1L / min.

[0043] The prepared welding wire was subjected to multiple cladding experiments, such as Figure 3As shown in the figure, the obtained cladding layer is uniform and continuous, with no pores or slag inclusions on the surface. The test results of the cladding layer show that after mechanical property testing and microstructure observation, the average microhardness can reach 420.3HV. 0.5 , the hydrogen diffusion coefficient is 2.08×10 -6 cm 2 / s, the hydrogen diffusion coefficient is smaller than that of the hydrogen storage tank base material (the hydrogen diffusion coefficient is 2.74×10 -6 cm 2 / s), indicating that the hydrogen resistance of the cladding layer obtained by laser cladding the small hydrogen storage tank body with the hydrogen-resistant flux-cored welding wire in the present invention is improved.

[0044] Example 4 In this embodiment, a small hydrogen storage tank body is used to prepare a cladding layer using a hydrogen-resistant flux-cored welding wire, which is specifically implemented in the following steps: Step 1, preparing a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank; Step 1-1, weigh the following powders by mass percentage: Ni: 40.98%, Cr: 17.0%, Fe: 15.0%, Nb: 4.8%, Mo: 7.21%, CeO2: 15.0%, C: 0.01%, the sum of the above raw material contents is 100%; Step 1-2, placing the drug powder weighed in step 1 in a ball mill, grinding the drug powder to fully mix the powders of each component and improve the original shape of the metal powder; stainless steel ball milling beads are selected in the ball mill, the diameter of the ball milling beads is 5mm, 10mm, 20mm, the ball milling speed reaches 300r / min, and the ball milling time is 2 hours; the powder particle size is 15~45µm; Step 1-3, filling the powder prepared in step 2 into a U-shaped welding skin, and closing the welding skin with a mold to obtain an original welding wire; the filling rate of the core powder in the welding skin is 25%; Step 1-4, the original welding wire is made into a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body with a set diameter by a step-by-step diameter reduction method, and impurities on the surface of the welding wire are removed; the diameter of the welding wire is 1.6 mm.

[0045] Step 2, using the welding wire prepared in step 1 to perform laser cladding; The laser power is 400W and the laser energy density is 200J / mm 3 , the scanning speed is 500mm / s; during the cladding process, 99% Ar gas by volume is used to protect the welding area, and the flow rate of the protective gas is 15.1L / min.

[0046] The prepared welding wire was subjected to multiple cladding experiments, such as Figure 4As shown in the figure, the obtained cladding layer is uniform and continuous, with no pores or slag inclusions on the surface. The test results of the cladding layer show that after mechanical property testing and microstructure observation, the average microhardness can reach 480.9HV. 0.5 , the hydrogen diffusion coefficient is 1.95×10 -6 cm 2 / s, the hydrogen diffusion coefficient is smaller than that of the hydrogen storage tank base material (the hydrogen diffusion coefficient is 2.74×10 -6 cm 2 / s), indicating that the hydrogen resistance of the cladding layer obtained by laser cladding the small hydrogen storage tank body with the hydrogen-resistant flux-cored welding wire in the present invention is improved.

[0047] Example 5 In this embodiment, a small hydrogen storage tank body is used to prepare a cladding layer using a hydrogen-resistant flux-cored welding wire, which is specifically implemented in the following steps: Step 1, preparing a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank; Step 1-1, weigh the following powders by mass percentage: Ni: 40.98%, Cr: 15.0%, Fe: 12.0%, Nb: 5.8%, Mo: 6.21%, CeO2: 20.0%, C: 0.01%, the sum of the above raw material contents is 100%; Step 1-2, placing the drug powder weighed in step 1 in a ball mill, grinding the drug powder to fully mix the powders of each component and improve the original shape of the metal powder; stainless steel ball milling beads are selected in the ball mill, the diameter of the ball milling beads is 5mm, 10mm, 20mm, the ball milling speed reaches 300r / min, and the ball milling time is 2 hours; the powder particle size is 15~45µm; Step 1-3, filling the powder prepared in step 2 into a U-shaped welding skin, and closing the welding skin with a mold to obtain an original welding wire; the filling rate of the core powder in the welding skin is 25%; Step 1-4, the original welding wire is made into a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body with a set diameter by a step-by-step diameter reduction method, and impurities on the surface of the welding wire are removed; the diameter of the welding wire is 1.6 mm.

[0048] Step 2, using the welding wire prepared in step 1 to perform laser cladding; The laser power is 400W and the laser energy density is 200J / mm 3 , the scanning speed is 500mm / s; during the cladding process, 99% Ar gas by volume is used to protect the welding area, and the flow rate of the protective gas is 14.5L / min.

[0049] The obtained welding wire was subjected to multiple cladding experiments. The obtained cladding layer was uniform and continuous, with no pores or slag inclusions on the surface. The cladding layer test results showed that after mechanical property test and microstructure observation, the average microhardness could reach 513.4HV0.5, and the hydrogen diffusion coefficient was 2.03×10 -6 cm 2 / s, the hydrogen diffusion coefficient is smaller than that of the hydrogen storage tank base material (the hydrogen diffusion coefficient is 2.74×10 -6 cm 2 / s), indicating that the hydrogen resistance of the cladding layer obtained by laser cladding the small hydrogen storage tank body with the hydrogen-resistant flux-cored welding wire in the present invention is improved.

[0050] Example 6 In this embodiment, a small hydrogen storage tank body is used to prepare a cladding layer using a hydrogen-resistant flux-cored welding wire, which is specifically implemented in the following steps: Step 1, preparing a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank; Step 1-1, weigh the following powders by mass percentage: Ni: 40.40%, Cr: 15.0%, Fe: 12.0%, Nb: 4.8%, Mo: 2.8%, CeO2: 25.0%, C 0.01%, the sum of the above raw material contents is 100%; Step 1-2, placing the drug powder weighed in step 1 in a ball mill, grinding the drug powder to fully mix the powders of each component and improve the original shape of the metal powder; stainless steel ball milling beads are selected in the ball mill, the diameter of the ball milling beads is 5mm, 10mm, 20mm, the ball milling speed reaches 300r / min, and the ball milling time is 2 hours; the powder particle size is 15~45µm; Step 1-3, filling the powder prepared in step 2 into a U-shaped welding skin, and closing the welding skin with a mold to obtain an original welding wire; the filling rate of the core powder in the welding skin is 25%; Step 1-4, the original welding wire is made into a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body with a set diameter by a step-by-step diameter reduction method, and impurities on the surface of the welding wire are removed; the diameter of the welding wire is 1.6 mm.

[0051] Step 2, using the welding wire prepared in step 1 to perform laser cladding; The laser power is 400W and the laser energy density is 200J / mm 3 , the scanning speed is 500mm / s; during the cladding process, 99% Ar gas by volume is used to protect the welding area, and the flow rate of the protective gas is 15.5L / min.

[0052] The obtained welding wire was subjected to multiple cladding experiments. The obtained cladding layer was uniform and continuous, with no pores or slag inclusions on the surface. The cladding layer test results showed that after mechanical property test and microstructure observation, the average microhardness could reach 524.7HV0.5, and the hydrogen diffusion coefficient was 2.16×10 -6 cm 2 / s, the hydrogen diffusion coefficient is smaller than that of the hydrogen storage tank base material (the hydrogen diffusion coefficient is 2.74×10 -6 cm 2 / s), indicating that the hydrogen resistance of the cladding layer obtained by laser cladding the small hydrogen storage tank body with the hydrogen-resistant flux-cored welding wire in the present invention is improved.

[0053] In summary, since the high-pressure hydrogen storage tank is expensive and difficult to process, low-carbon steel is used to prepare the hydrogen storage tank and the internal surface cladding layer is modified. The hardness, corrosion resistance and hydrogen resistance of the inner surface of the hydrogen storage tank can be improved by the method of the present invention.

Claims

1. Hydrogen-resistant flux-cored welding wire for small hydrogen storage tanks, characterized in that: Including flux core and welding skin, the flux core is composed of the following components by mass percentage: Ni powder 40%~60%, Cr powder 17.0%~21.0%, Fe powder 15%~19%, Nb powder 4.75%~7.45%, Mo powder 2.8%~4.3%, CeO2 powder 5.0%~15.0%, C powder 0.02%~0.10%. The sum of the mass percentages of the above components is 100%.

2. The hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank according to claim 1, characterized in that: The powder particle size of the drug core is 15-45 μm.

3. The hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank according to claim 1, characterized in that: The welding skin is a nickel-based alloy strip.

4. The hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank according to claim 1, characterized in that: The filling rate of the flux core in the welding skin is 18% to 25%.

5. A method for preparing a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank, characterized in that: Follow the steps below to implement it: Step 1: Weigh the following powders by mass percentage: Ni powder 40%~60%, Cr powder 17.0%~21.0%, Fe powder 15%~19%, Nb powder 4.75%~7.45%, Mo powder 2.8%~4.3%, CeO2 powder 5.0%~15.0%, C powder 0.02%~0.10%, the sum of the mass percentages of the above components is 100%; Step 2: placing the powder weighed in step 1 into a ball mill, grinding the powder to fully mix the powders of each component and improve the original shape of the metal powder; Step 3, filling the powder prepared in step 2 into the U-shaped welding skin, and closing the welding skin with a mold to obtain the original welding wire; Step 4: The original welding wire is made into a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank body with a set diameter by a step-by-step diameter reduction method, and impurities on the surface of the welding wire are removed.

6. The method for preparing the hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank according to claim 5, characterized in that: In step 2, the ball mill jar is made of stainless steel ball mill beads, the diameter of the ball mill beads is 5mm, 10mm, and 20mm, the ball mill speed reaches 200-300r / min, and the ball milling time is 2-3 hours; the powder particle size is 15-45µm.

7. The method for preparing the hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank according to claim 5, characterized in that: The welding skin described in step 3 is a nickel-based alloy strip.

8. The method for preparing the hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank according to claim 5, characterized in that: In step 3, the filling rate of the flux core powder in the welding skin is controlled at 18% to 25%.

9. A cladding method for a hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank, characterized in that: Laser cladding is performed using the hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank according to any one of claims 1 to 4, and is specifically implemented in the following steps: S1. Set the laser welding equipment parameters: laser power 350~400W, laser energy density range 50~200J / mm 3 , scanning speed is 400~500mm / s; S2, select the above-mentioned small hydrogen storage tank with the required diameter and load the hydrogen-resistant flux-cored welding wire into the wire feeding mechanism, set the wire feeding speed, and continuously introduce the protective gas; S3. Fix the workpiece on the workbench, start the laser equipment and wire feeding mechanism, and perform laser cladding operation according to the preset scanning path and process parameters in a protective gas environment to obtain a cladding layer.

10. The cladding method of the hydrogen-resistant flux-cored welding wire for a small hydrogen storage tank according to claim 9, characterized in that: The protective gas described in S2 is Ar with a volume fraction of 99%, and the flow rate of the protective gas is 13~16L / min.

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