A high fracture toughness gas-electric vertical welding flux-cored wire for storage tanks

Abstract

The application provides a kind of high fracture toughness gas-electric vertical welding flux-cored wire for storage tank, including core and sheath, the core accounts for 22-25% of total mass of welding wire;The core includes the following components by weight fraction: titanium dioxide 6-12 parts, quartz 8-12 parts, fluoride 30-50 parts, carbonate 14-24 parts, magnesium oxide 3-8 parts, calcium oxide 3-8 parts, silicon-manganese alloy 70-90 parts, electrolytic manganese 30-40 parts, magnesium powder 6-10 parts, aluminum-magnesium alloy 6-10 parts, silicon iron 10-20 parts, ferromolybdenum 10-15 parts, titanium boride alloy 15-25 parts, nickel powder 25-30 parts, iron powder is 700 parts;Wherein, fluoride:(titanium dioxide+quartz)=(1.5-2.5):1.The welding wire has good tensile strength, low temperature impact toughness and fracture toughness.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of welding wire production, and particularly relates to a high-fracture-toughness gas-electric vertical welding flux-cored wire for storage tanks. BACKGROUND

[0002] In the tide of the increasingly prosperous economy and the accelerating industrialization process in China, as important storage and storage and transportation equipment, the importance of large storage tanks is increasingly prominent. In many fields such as petroleum, chemical industry, natural gas and food, they bear the heavy responsibility of storage and transportation and become an important link to ensure the smoothness of the supply chain. The large storage tank industry is showing a booming trend. Fracture toughness is an important indicator reflecting the mechanical properties of materials, which affects the service life and performance of materials. High-fracture-toughness materials can maintain high strength and stability under stress, and have longer service life and durability. The steel used in the storage tank industry has a large thickness and severe service conditions. The gas-electric vertical welding process is widely used. The invention of a high-fracture-toughness gas-electric vertical welding flux-cored wire is of great significance to the safety and reliability of the storage tank industry in China. SUMMARY

[0003] Therefore, the present application aims to provide a high-fracture-toughness gas-electric vertical welding flux-cored wire for storage tanks, which has good arc stability, less spatter, good appearance, easy slag removal, and excellent fracture toughness, fully meeting the high demand standards of gas-electric vertical welding.

[0004] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0005] A high-fracture-toughness gas-electric vertical welding flux-cored wire for storage tanks comprises a core and an outer skin, and the core accounts for 22-25% of the total mass of the welding wire. The core comprises the following components in parts by weight: 6-12 parts of titanium dioxide, 8-12 parts of quartz, 30-50 parts of fluoride, 14-24 parts of carbonate, 3-8 parts of magnesium oxide, 3-8 parts of calcium oxide, 70-90 parts of silicon-manganese alloy, 30-40 parts of electrolytic manganese, 6-10 parts of magnesium powder, 6-10 parts of aluminum-magnesium alloy, 10-20 parts of silicon iron, 10-15 parts of molybdenum iron, 15-25 parts of titanium boride alloy, 25-30 parts of nickel powder, and 700 parts of iron powder. The fluoride:(titanium dioxide+quartz) ratio is (1.5-2.5):1.

[0006] Further, the fluoride is a mixture of sodium fluoride and calcium fluoride, and the core contains 15-25 parts of sodium fluoride and 15-25 parts of calcium fluoride by weight.

[0007] Further, the carbonate is a mixture of sodium carbonate and potassium carbonate.

[0008] Further, the core contains 8-12 parts of sodium carbonate and 6-12 parts of potassium carbonate by weight.

[0009] Further, the diameter of the welding wire is 1.6mm.

[0010] Further, the deposited metal tensile strength of the welding wire is greater than or equal to 490MPa, the yield strength is greater than or equal to 390MPa, the elongation is greater than or equal to 20%, the impact toughness at-20 DEG C is greater than or equal to 60J, and the fracture toughness index of the welded joint is: the crack tip opening displacement CTOD at-20 DEG C is greater than or equal to 0.25mm.

[0011] The fluoride is a mixture of sodium fluoride and calcium fluoride, the fluoride is a main slag forming agent, can play a role in diluting slag, and is beneficial to slag removal. Calcium fluoride is used in the traditional flux-cored wire formula, which is a good dehydrogenation substance, but when the content is relatively high, it is not conducive to arc stability, the spatter increases, and the welding process is affected. The application preferably uses a mixture of sodium fluoride and calcium fluoride, and the sodium fluoride is a good arc stabilizer. Under the condition of ensuring the optimal dehydrogenation and arc stability effect, the sodium fluoride can reduce the slag viscosity and improve the slag physical and chemical properties, which is beneficial to slag removal. The fluoride improves the slag basicity, purifies the weld metal purity, and improves the CTOD value of the weld metal.

[0012] The carbonate is a main slag forming agent, can improve the viscosity of the molten slag, and the generated CO2 plays a role in protecting the molten pool. The application preferably uses a mixture of sodium carbonate and potassium carbonate. Na2O is a low ionization degree oxide, can provide electrons, and can play a role in stabilizing the arc together with K2O, thereby improving the welding process performance.

[0013] Magnesium powder and electrolytic manganese are main deoxidizers and desulfurizers, which can effectively reduce the impurity content of the deposited metal. The oxidation product MgO of the magnesium powder can improve the slag basicity and improve the low-temperature impact toughness of the deposited metal.

[0014] Titanium boron alloy: Ti can refine the weld metal organization, promote the formation of acicular ferrite in the weld metal, refine the grain, and improve the mechanical properties of the deposited metal. Titanium element can also form stable carbide, avoid the precipitation of Cr-rich carbide on the grain boundary, and thus the addition of titanium element can also prevent intergranular corrosion.

[0015] Nickel powder and molybdenum iron: the joint action can inhibit the formation of pro-eutectoid ferrite, refine the grain, and improve the low-temperature impact toughness and CTOD value of the deposited metal.

[0016] Silicon iron and silicon manganese alloy: silicon is an important deoxidizer and an important alloying agent of the weld metal. The appropriate amount of silicon element can improve the impact toughness of the weld metal. Silicon and manganese have formed a mature toughening mechanism, and can also play a joint deoxidization effect.

[0017] Iron powder: the application selects reduced iron powder, and the addition of iron powder in the flux-cored wire can improve the welding efficiency and provide a small amount of oxygen to play a role in stabilizing the arc.

[0018] Compared with the prior art, the high fracture toughness gas-electric vertical welding flux-cored wire for storage tanks has the following advantages:

[0019] The high-fracture-toughness gas-electric vertical welding flux-cored wire for storage tanks has good tensile strength, low-temperature impact toughness and fracture toughness, is used for gas-electric vertical welding of the side plates of storage tanks, and can effectively improve the safety of the butt welds of the storage tanks, prolong the service life, and reduce the welding material cost and comprehensive maintenance cost. DETAILED DESCRIPTION

[0020] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0022] Embodiment 1

[0023] A high-fracture-toughness gas-electric vertical welding flux-cored wire for storage tanks has a wire diameter of 1.6 mm, and includes a core and a sheath. The core accounts for 24% of the total mass of the wire. The core includes the following components in parts by weight: 10 parts of titanium dioxide, 10 parts of quartz, 20 parts of sodium fluoride, 20 parts of calcium fluoride, 10 parts of sodium carbonate, 9 parts of potassium carbonate, 5 parts of magnesium oxide, 5 parts of calcium oxide, 70 parts of silicon-manganese alloy, 40 parts of electrolytic manganese, 10 parts of magnesium powder, 6 parts of aluminum-magnesium alloy, 20 parts of silicon-iron, 15 parts of molybdenum-iron, 15 parts of titanium-boron alloy, 25 parts of nickel powder, and 700 parts of iron powder.

[0024] In the formula, (sodium fluoride + calcium fluoride) : (titanium dioxide + quartz) = 2:1.

[0025] Embodiment 2

[0026] A high-fracture-toughness gas-electric vertical welding flux-cored wire for storage tanks has a wire diameter of 1.6 mm, and includes a core and a sheath. The core accounts for 22% of the total mass of the wire. The core includes the following components in parts by weight: 6 parts of titanium dioxide, 12 parts of quartz, 25 parts of sodium fluoride, 15 parts of calcium fluoride, 8 parts of sodium carbonate, 12 parts of potassium carbonate, 8 parts of magnesium oxide, 3 parts of calcium oxide, 80 parts of silicon-manganese alloy, 35 parts of electrolytic manganese, 8 parts of magnesium powder, 8 parts of aluminum-magnesium alloy, 15 parts of silicon-iron, 13 parts of molybdenum-iron, 25 parts of titanium-boron alloy, 30 parts of nickel powder, and 700 parts of iron powder.

[0027] In the formula, (sodium fluoride + calcium fluoride) : (titanium dioxide + quartz) = 2.22:1.

[0028] Embodiment 3

[0029] A kind of high fracture toughness gas-electric vertical welding flux-cored wire for storage tank, the diameter of welding wire is 1.6 mm, including core and sheath, the core accounts for 23% of the total mass of welding wire;The core includes the following components by weight fraction: titanium dioxide 12 parts, quartz 8 parts, sodium fluoride 15 parts, calcium fluoride 25 parts, sodium carbonate 12 parts, potassium carbonate 6 parts, magnesium oxide 3 parts, calcium oxide 8 parts, silicon-manganese alloy 90 parts, electrolytic manganese 30 parts, magnesium powder 6 parts, aluminum-magnesium alloy 10 parts, silicon iron 10 parts, molybdenum iron 10 parts, titanium boron alloy 20 parts, nickel powder 27 parts, iron powder 700 parts.

[0030] Wherein, (sodium fluoride+calcium fluoride) :(titanium dioxide+quartz)=2:1.

[0031] Table 1 Example 1-3 flux-cored wire deposited metal chemical composition (%)

[0032] Test item C S Mn Si P Ni Mo Ti Example 1 0.071 0.006 1.68 0.25 0.009 0.58 0.21 0.038 Example 2 0.068 0.005 1.71 0.26 0.008 0.65 0.17 0.045 Example 3 0.065 0.005 1.75 0.26 0.009 0.62 0.14 0.036

[0033] Table 2 Example 1-3 flux-cored wire deposited metal mechanical properties

[0034]

[0035]

[0036] As can be seen from Table 2, the tensile strength of the flux-cored wire deposited metal according to the application is ≥490 MPa, the yield strength is ≥390 MPa, the elongation is ≥20%, the impact toughness at -20℃ is ≥60 J, and the fracture toughness index of the welded joint is: the crack tip opening displacement CTOD at -20℃ is ≥0.25 mm.

[0037] Comparative Example 1 has too many alloying elements

[0038] A kind of high fracture toughness gas-electric vertical welding flux-cored wire for storage tank, the diameter of welding wire is 1.6 mm, including core and sheath, the core accounts for 24% of the total mass of welding wire;The core includes the following components by weight fraction: titanium dioxide 10 parts, quartz 10 parts, sodium fluoride 20 parts, calcium fluoride 20 parts, sodium carbonate 10 parts, potassium carbonate 9 parts, magnesium oxide 5 parts, calcium oxide 5 parts, silicon-manganese alloy 100 parts, electrolytic manganese 50 parts, magnesium powder 10 parts, aluminum-magnesium alloy 6 parts, silicon iron 25 parts, molybdenum iron 25 parts, titanium boron alloy 15 parts, nickel powder 25 parts, iron powder 700 parts.

[0039] Table 3 Comparative Example 1 flux-cored wire deposited metal chemical composition (%)

[0040] Test item C S Mn Si P Ni Mo Ti Comparative Example 1 0.08 0.005 2.22 0.36 0.011 0.55 0.32 0.052

[0041] Table 4 Comparative Example 1 flux-cored wire deposited metal mechanical properties

[0042]

[0043] Example 2: Insufficient slagging agent

[0044] A high fracture toughness gas-electric vertical welding flux-cored wire for storage tanks, the wire diameter is 1.6mm, including a core and a sheath, the core accounts for 22% of the total mass of the wire; the core includes the following components in parts by weight: titanium dioxide 4 parts, quartz 6 parts, sodium fluoride 10 parts, calcium fluoride 10 parts, sodium carbonate 8 parts, potassium carbonate 12 parts, magnesium oxide 8 parts, calcium oxide 3 parts, silicon-manganese alloy 80 parts, electrolytic manganese 35 parts, magnesium powder 8 parts, aluminum-magnesium alloy 8 parts, silicon-iron 15 parts, molybdenum-iron 13 parts, titanium-boron alloy 25 parts, nickel powder 30 parts, iron powder 700 parts.

[0045] Table 5 Chemical composition of deposited metal of the flux-cored wire of Example 2 (%)

[0046] Test item C S Mn Si P Ni Mo Ti Comparative Example 2 0.006 0.006 1.65 0.28 0.012 0.45 0.19 0.036

[0047] Table 6 Mechanical properties of deposited metal of the flux-cored wire of Example 2

[0048]

[0049] Example 3: The ratio of fluoride to (titanium dioxide + quartz) does not meet the requirements

[0050] Scheme a: Fluoride:(titanium dioxide + quartz) = 1.25 (less than the specified ratio)

[0051] A high fracture toughness gas-electric vertical welding flux-cored wire for storage tanks, the wire diameter is 1.6mm, including a core and a sheath, the core accounts for 23% of the total mass of the wire; the core includes the following components in parts by weight: titanium dioxide 12 parts, quartz 12 parts, sodium fluoride 15 parts, calcium fluoride 15 parts, sodium carbonate 12 parts, potassium carbonate 6 parts, magnesium oxide 3 parts, calcium oxide 8 parts, silicon-manganese alloy 90 parts, electrolytic manganese 30 parts, magnesium powder 6 parts, aluminum-magnesium alloy 10 parts, silicon-iron 10 parts, molybdenum-iron 10 parts, titanium-boron alloy 20 parts, nickel powder 27 parts, iron powder 700 parts.

[0052] Scheme b: Fluoride:(titanium dioxide + quartz) = 2.86 (greater than the specified ratio)

[0053] A high fracture toughness gas-electric vertical welding flux-cored wire for storage tanks, the wire diameter is 1.6mm, including a core and a sheath, the core accounts for 23% of the total mass of the wire; the core includes the following components in parts by weight: titanium dioxide 8 parts, quartz 6 parts, sodium fluoride 15 parts, calcium fluoride 25 parts, sodium carbonate 12 parts, potassium carbonate 6 parts, magnesium oxide 3 parts, calcium oxide 8 parts, silicon-manganese alloy 90 parts, electrolytic manganese 30 parts, magnesium powder 6 parts, aluminum-magnesium alloy 10 parts, silicon-iron 10 parts, molybdenum-iron 10 parts, titanium-boron alloy 20 parts, nickel powder 27 parts, iron powder 700 parts.

[0054] Table 7 Chemical composition of deposited metal of comparative example 3 (%)

[0055] Test item C S Mn Si P Ni Mo Ti Scheme a 0.067 0.007 1.68 0.26 0.011 0.48 0.18 0.038 Scheme b 0.065 0.006 1.66 0.25 0.012 0.46 0.17 0.036

[0056] Table 8 Mechanical properties of deposited metal of comparative example 3

[0057]

[0058] Result analysis:

[0059] Comparative example 1 has too much alloying elements, which leads to too high tensile strength of the deposited metal, and reduces the elongation, and greatly affects the impact toughness and crack tip opening displacement.

[0060] Comparative example 2 has insufficient slag forming agent, which leads to large area of weld surface without slag coverage, and thus affects the impact toughness and crack tip opening displacement.

[0061] Comparative example 3 has (sodium fluoride + calcium fluoride) : (titanium dioxide + quartz) ratio exceeding the requirement, which leads to poor weld structure purity when the oxide ratio is too high, and affects the impact toughness and crack tip opening displacement; and when the fluoride ratio is too high, the melting point of the slag is high, and there is too much slag in the molten pool, which leads to poor weld forming.

[0062] In summary, the process performance and mechanical properties of the flux-cored wires of examples 1-3 are better than those of the comparative example.

[0063] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high fracture toughness gas electrically welded flux cored welding wire for storage tanks, characterized by: The welding wire comprises a core and a sheath, the core accounts for 22-25% of the total mass of the welding wire; the core is composed of components in the following proportions by weight Composition: titanium dioxide 6-12 parts, quartz 8-12 parts, fluoride 30-50 parts, carbonate 14-24 parts, magnesium oxide 3-8 parts, calcium oxide 3-8 parts, silicon-manganese alloy 70-90 parts, electrolytic manganese 30-40 parts, magnesium powder 6-10 parts, aluminum-magnesium alloy 6-10 parts, ferrosilicon 10-20 parts, ferromolybdenum 10-15 parts, titanium-boron alloy 15-25 parts, nickel powder 25-30 parts, and iron powder 700 parts; wherein, fluoride:(titanium dioxide+quartz)= (1.5-2.5):

1. The fluoride is a mixture of sodium fluoride and calcium fluoride, and the sodium fluoride is 15-25 parts and the calcium fluoride is 15-25 parts by weight.

2. The high fracture toughness gas-tungsten welded pipe core welding wire for storage tanks according to claim 1, characterized by: The carbonate is a mixture of sodium carbonate and potassium carbonate.

3. The high fracture toughness gas-tungsten welded pipe for storage tank according to claim 2, characterized by: The sodium carbonate is 8-12 parts and the potassium carbonate is 6-12 parts by weight.

4. The high fracture toughness gas-tungsten welded pipe for storage tank according to claim 1, characterized by: The diameter of the welding wire is 1.6 mm.

5. The high fracture toughness gas-tungsten welded pipe for storage tank according to claim 1, characterized by: The deposited metal of the welding wire has a tensile strength of ≥490 MPa, a yield strength of ≥390 MPa, an elongation of ≥20%, an impact toughness at -20 ℃ of ≥60 J, and a fracture toughness index of the welded joint: a crack tip opening displacement CTOD at -20 ℃ of ≥0.25 mm.

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