A flux-cored wire for flat welding and flat fillet welding and use thereof

Abstract

The present application belongs to the technical field of welding material, and specifically provides a flux-cored wire for flat welding and flat angle welding, which comprises a sheath and a flux filled in the sheath, and the flux comprises 0.5-2% of fluoride, 10-25% of rutile, 3-6% of feldspar, 2-6% of zirconium sand, 8-12% of ferrosilicon, 1-7% of ferrotitanium, 3-7% of ferroboron, 10-15% of electrolytic manganese, 0-3% of nickel powder, 1-5% of potassium titanate, 2-4% of magnesium powder, and the balance of Fe and inevitable impurities in terms of mass percentage. The flux-cored wire provided by the present application is matched with CO2 gas protection, the welding arc is stable, the melting is uniform, the molten slag has good fluidity, the weld forming is beautiful, and the welding speed on the zinc-rich primer plate can reach 1000-1200 mm / min without pores. The average value of deposited metal-20 ℃ KV2 is greater than or equal to 80 J, the weld elongation is greater than or equal to 26%, and the diffusible hydrogen content detected by mercury method is less than 5.0 mL / 100g.

Description

Technical Field

[0001] This invention belongs to the field of welding materials technology, specifically relating to a flux-cored welding wire for flat welding and fillet welding and its application. Background Technology

[0002] In actual production, to prevent steel from rusting during processing, transportation, and storage, most steel surfaces are pre-coated with shop primer. Among them, inorganic zinc primer has become one of the most widely used types of shop primer due to its excellent rust prevention and weather resistance. However, when performing fillet welding on steel pre-coated with inorganic zinc primer, conventional all-position flux-cored wire welding is prone to defects such as weld porosity. The main reason is that the zinc powder and organic matter in the primer decompose at the high welding temperature, producing zinc vapor and other volatiles. These volatiles are difficult to escape from the weld pool quickly and are easily encapsulated by the solidified molten metal, forming pores. This seriously affects the density and mechanical properties of the weld, and may even lead to weld failure, causing safety hazards.

[0003] As the welding industry moves towards automation and efficiency, automated and efficient welding technology has become an inevitable trend, placing higher demands on the performance of welding materials. High-speed fillet welding flux-cored wire, with its characteristics of less slag and easier gas escape from the weld pool, is particularly suitable for fillet welding operations. When welding steel pre-coated with inorganic zinc primer, it can effectively replace all-position flux-cored wire, significantly improving weld porosity. Furthermore, its deposition efficiency is far higher than that of all-position flux-cored wire, effectively improving welding production efficiency and reducing production costs. Therefore, it is gradually becoming the preferred material for high-efficiency fillet welding operations. Despite its significant advantages, high-speed fillet welding flux-cored wire currently suffers from problems such as poor weld formation quality and insufficient low-temperature mechanical properties. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of poor weld formation and insufficient low-temperature mechanical properties of existing high-speed fillet welding flux-cored wires.

[0005] Therefore, the present invention provides a flux-cored welding wire for flat welding and fillet welding, comprising an outer sheath and a flux core filled within the outer sheath. By mass percentage, the flux core comprises 0.5-2% fluoride, 10-25% rutile, 3-6% feldspar, 2-6% zircon sand, 8-12% ferrosilicon, 1-7% ferrotitanium, 3-7% ferroboron, 10-15% electrolytic manganese, 0-3% nickel powder, 1-5% potassium titanate, 2-4% magnesium powder, with the balance being Fe and unavoidable impurities.

[0006] Specifically, the aforementioned fluorides include one or more of sodium fluoride, lithium fluoride, and sodium fluorosilicate.

[0007] Specifically, the mass percentage of boron in the aforementioned ferroboron is 1%.

[0008] Specifically, by mass percentage, the outer sheath of the flux-cored wire accounts for 82-86%, and the flux core accounts for 14-18%.

[0009] Specifically, the aforementioned outer skin is a carbon steel outer skin.

[0010] Specifically, by mass percentage, the carbon steel outer skin comprises C: 0.02%-0.04%, Si≤0.03%, Mn: 0.2%-0.4%, S≤0.005%, P≤0.005%, with the balance being iron.

[0011] Specifically, by mass percentage, the core comprises 0.5% fluoride, 10% rutile, 3% feldspar, 2% zircon sand, 8% ferrosilicon, 1% ferrotitanium, 3% ferroboron, 10% electrolytic manganese, 1% potassium titanate, 2% magnesium powder, with the balance being Fe and unavoidable impurities.

[0012] Specifically, by mass percentage, the core comprises 2% fluoride, 25% rutile, 6% feldspar, 6% zircon sand, 12% ferrosilicon, 7% ferrotitanium, 7% ferroboron, 15% electrolytic manganese, 3% nickel powder, 5% potassium titanate, 4% magnesium powder, with the balance being Fe and unavoidable impurities.

[0013] Specifically, by mass percentage, the core comprises 1% fluoride, 20% rutile, 4.5% feldspar, 4.5% zircon sand, 10% ferrosilicon, 4.5% ferrotitanium, 5% ferroboron, 13% electrolytic manganese, 2% nickel powder, 3% potassium titanate, 3% magnesium powder, with the balance being Fe and unavoidable impurities.

[0014] The flux-cored welding wire provided by this invention for flat welding and fillet welding can be used for welding primer-coated steel.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0016] The flux-cored welding wire provided by this invention, used for flat and fillet welding, combined with CO2 gas protection, provides a stable welding arc, uniform melting, good slag fluidity, and aesthetically pleasing weld formation. Welding speeds on zinc-rich primer plates can reach 1000-1200 mm / min without porosity. The deposited metal at -20℃ has an average KV2 value ≥80 J, weld elongation ≥26%, and diffusible hydrogen content (mercury method test) <5.0 mL / 100g. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Although representative embodiments of the present invention have been described in detail, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the embodiments, but should be defined by the appended claims and their equivalents.

[0018] This invention provides a flux-cored welding wire for flat welding and fillet welding, comprising an outer sheath and a flux core filled within the outer sheath. By mass percentage, the flux core comprises 0.5–2% fluoride, 10–25% rutile, 3–6% feldspar, 2–6% zircon sand, 8–12% ferrosilicon, 1–7% ferrotitanium, 3–7% ferroboron, 10–15% electrolytic manganese, 0–3% nickel powder, 1–5% potassium titanate, 2–4% magnesium powder, with the balance being Fe and unavoidable impurities. The fluoride preferably includes one or more of sodium fluoride, lithium fluoride, and sodium fluorosilicate; the ferroboron preferably has a boron content of 1% by mass.

[0019] The design principles for each component are as follows:

[0020] Fluorides play a role in slag formation, improving slag fluidity, and removing hydrogen. By adding one or a mixture of sodium fluoride, lithium fluoride, and sodium fluorosilicate, the diffusible hydrogen is reduced. The amount added is controlled at 0.5% to 2%.

[0021] The main component of rutile, TiO2, is the primary component forming welding slag. The addition of TiO2 can stabilize the arc, reduce welding spatter, and improve slag coverage and slag removal. When the amount of TiO2 in the flux core is too small, the slag coverage is incomplete; when the amount of TiO2 in the flux core is too large, the slag is too thick, which is not conducive to gas escape. Therefore, the percentage of TiO2 in the total weight of the flux core powder is 10-25%.

[0022] Feldspar's main components are Al2O3, K2O, Na2O, and SiO2, which are also the main components of slag. It can adjust the melting point and viscosity of slag, improve weld formation, facilitate a smooth transition of the weld to the base metal, increase the interface between slag and weld, and give the slag good coverage. Therefore, feldspar accounts for 3-6% of the total weight of the flux core powder.

[0023] Zircon sand's main component, ZrO2, is also a major component of slag. It can adjust the slag's melting point and viscosity, and improve weld formation. Therefore, feldspar accounts for 2-6% of the total weight of the flux core powder.

[0024] The main component of potassium titanate, TiO2, can stabilize the electric arc and reduce welding spatter. However, excessive addition will lead to increased welding fumes. Therefore, potassium titanate accounts for 1-5% of the total weight of the flux core powder.

[0025] Nickel powder is mainly used to improve the low-temperature impact toughness of weld metal. Considering cost factors, the percentage of nickel powder in the total weight of the flux-cored powder is 0-3%.

[0026] Titanium iron is a strong deoxidizer that improves low-temperature impact toughness. When its addition is less than 1%, its ability to improve low-temperature impact toughness is insufficient, and when its addition is greater than 7%, no more significant improvement in low-temperature impact toughness is observed. Therefore, the percentage of titanium iron in the total weight of the core powder is 1-7%.

[0027] Ferroboron is mainly used in combination with ferrotitanium to refine grains and improve low-temperature impact toughness. When its addition is less than 1%, its ability to improve low-temperature impact toughness is insufficient, and when its addition is greater than 7%, it is detrimental to the crack resistance of the weld. Therefore, 1% ferroboron accounts for 1% to 7% of the total weight of the flux core powder.

[0028] Ferrosilicon (Si-Fe) is the main deoxidizer. Adding an appropriate amount can improve the process and deoxidation, and can also increase the fluidity of molten iron, which is beneficial for high-speed welding. However, adding too much is detrimental to the process performance. Therefore, ferrosilicon accounts for 8-12% of the total weight of the flux core powder.

[0029] Electrolytic manganese is the main deoxidizer used to reduce the oxygen content of weld metal, increase the strength and crack resistance of weld metal, improve low-temperature impact toughness, and regulate the fluidity of molten iron. Therefore, Mn accounts for 10-15% of the total weight of the flux core powder.

[0030] Magnesium powder is a strong deoxidizer that improves low-temperature impact toughness. When its addition is less than 2%, its ability to improve low-temperature impact toughness is insufficient, while when the addition is greater than 4%, it is not conducive to the removal of weld gas and weld formation. Therefore, the percentage of magnesium powder in the total weight of the flux-cored powder is 2-4%.

[0031] S and P are impurity elements that severely affect the weld metal's resistance to hydrogen sulfide and reduce its low-temperature impact toughness. S forms sulfide inclusions with elements such as Fe, which can induce pitting corrosion and stress corrosion cracking. P has a strong segregation effect, causing unevenness in the weld metal, especially increasing cold brittleness. Therefore, the lower the content of S and P, the better.

[0032] Fe, or iron powder, can improve the state of the electric arc and adjust the melting point and viscosity of molten iron. The remainder is added.

[0033] Specifically, the outer sheath accounts for 82-86% of the flux-cored wire, while the flux core accounts for 14-18%.

[0034] Furthermore, the outer skin is a carbon steel outer skin. By mass percentage, the carbon steel outer skin comprises C: 0.02%-0.04%, Si≤0.03%, Mn: 0.2%-0.4%, S≤0.005%, P≤0.005%, with the balance being iron.

[0035] The following specific embodiments illustrate the effectiveness of the flux-cored welding wire for flat welding and fillet welding according to the present invention. In these embodiments, the flux-cored welding wire is prepared using conventional welding wire manufacturing processes in the art, and the mass percentage of boron in the ferroboron is 1%.

[0036] Example 1:

[0037] This embodiment provides a flux-cored welding wire for flat welding and fillet welding, comprising a carbon steel outer sheath and a flux core filled within the outer sheath, the flux core accounting for 18% of the total mass of the flux-cored welding wire. By mass percentage, the flux core comprises: lithium fluoride: 0.5%, rutile: 10%, feldspar: 3%, zircon sand: 2%, 45# ferrosilicon: 8%, ferrotitanium: 1%, ferroboron: 3%, electrolytic manganese: 10%, nickel powder: 0%, potassium titanate: 1%, magnesium powder: 2%, with the balance being Fe and unavoidable impurities.

[0038] The carbon steel outer sheath is made of low S and P carbon steel strip. The chemical composition of the carbon steel strip is C: 0.04%, Si: 0.03%, Mn: 0.3%, S: 0.004%, P: 0.005%, with the balance being iron.

[0039] The flux-cored wire prepared in this embodiment was tested. The chemical composition test results of the deposited metal are shown in Table 1, the mechanical property test results are shown in Table 2, and the diffusion hydrogen test (mercury method) results are shown in Table 3.

[0040] Example 2:

[0041] This embodiment provides a flux-cored welding wire for flat welding and fillet welding, comprising a carbon steel outer sheath and a flux core filled within the outer sheath, the flux core accounting for 14% of the total mass of the flux-cored welding wire. By mass percentage, the flux core comprises: sodium fluorosilicate: 2%, rutile: 25%, feldspar: 6%, zircon sand: 6%, 45# ferrosilicon: 12%, ferrotitanium: 7%, ferroboron: 7%, electrolytic manganese: 15%, nickel powder: 3%, potassium titanate: 5%, magnesium powder: 4%, with the balance being Fe and unavoidable impurities.

[0042] The carbon steel outer sheath is made of low S and P carbon steel strip. The chemical composition of the carbon steel strip is C: 0.03%, Si: 0.03%, Mn: 0.2%, S: 0.004%, P: 0.005%, with the balance being iron.

[0043] The flux-cored wire prepared in this embodiment was tested. The chemical composition test results of the deposited metal are shown in Table 1, the mechanical property test results are shown in Table 2, and the diffusion hydrogen test (mercury method) results are shown in Table 3.

[0044] Example 3:

[0045] This embodiment provides a flux-cored welding wire for flat welding and fillet welding, comprising a carbon steel outer sheath and a flux core filled within the outer sheath, the flux core accounting for 16% of the total mass of the flux-cored welding wire. By mass percentage, the flux core comprises: sodium fluoride: 1%, rutile: 20%, feldspar: 4.5%, zircon sand: 4.5%, 45# ferrosilicon: 10%, ferrotitanium: 4.5%, ferroboron: 5%, electrolytic manganese: 13%, nickel powder: 2%, potassium titanate: 3%, magnesium powder: 3%, with the balance being Fe and unavoidable impurities.

[0046] The carbon steel outer sheath is made of low S and P carbon steel strip. The chemical composition of the carbon steel strip is C: 0.02%, Si: 0.03%, Mn: 0.4%, S: 0.004%, P: 0.005%, with the balance being iron.

[0047] The flux-cored wire prepared in this embodiment was tested. The chemical composition test results of the deposited metal are shown in Table 1, the mechanical property test results are shown in Table 2, and the diffusion hydrogen test (mercury method) results are shown in Table 3.

[0048] Table 1 Chemical composition of flux-cored wire deposited metal

[0049]

[0050] Table 2 Mechanical properties of flux-cored welding wire

[0051]

[0052] Table 3. Test of diffused hydrogen content in flux-cored welding wire

[0053]

[0054] Example 4:

[0055] The 1.4mm flux-cored welding wire prepared in Examples 1-3 was used to weld fillet welds on zinc-rich primer plates. The welding currents were 300A and 34V, and the welding speeds were 1000 and 1200mm / min, respectively. Macroscopic and fracture tests of the welds after welding showed no porosity.

[0056] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A flux-cored welding wire for flat welding and fillet welding, comprising an outer sheath and a flux core filled within the outer sheath, characterized in that: By mass percentage, the core comprises 0.5-2% fluoride, 10-25% rutile, 3-6% feldspar, 2-6% zircon sand, 8-12% ferrosilicon, 1-7% ferrotitanium, 3-7% ferroboronium, 10-15% electrolytic manganese, 0-3% nickel powder, 1-5% potassium titanate, 2-4% magnesium powder, with the balance being Fe and unavoidable impurities.

2. The flux-cored welding wire for flat welding and fillet welding as described in claim 1, characterized in that: The fluoride includes one or more of sodium fluoride, lithium fluoride, and sodium fluorosilicate.

3. The flux-cored welding wire for flat welding and fillet welding as described in claim 1, characterized in that: The mass percentage of boron in the ferroboron is 1%.

4. The flux-cored welding wire for flat welding and fillet welding as described in claim 1, characterized in that: By mass percentage, the outer sheath of the flux-cored wire accounts for 82-86%, and the flux core accounts for 14-18%.

5. The flux-cored welding wire for flat welding and fillet welding as described in claim 1, characterized in that: The outer skin is made of carbon steel.

6. The flux-cored welding wire for flat welding and fillet welding as described in claim 5, characterized in that, By mass percentage, the carbon steel outer skin comprises C: 0.02%-0.04%, Si≤0.03%, Mn: 0.2%-0.4%, S≤0.005%, P≤0.005%, with the balance being iron.

7. The flux-cored welding wire for flat welding and fillet welding as described in claim 1, characterized in that: By weight percentage, the core comprises 0.5% fluoride, 10% rutile, 3% feldspar, 2% zircon sand, 8% ferrosilicon, 1% ferrotitanium, 3% ferroboron, 10% electrolytic manganese, 1% potassium titanate, 2% magnesium powder, with the balance being Fe and unavoidable impurities.

8. The flux-cored welding wire for flat welding and fillet welding as described in claim 1, characterized in that: By weight percentage, the core comprises 2% fluoride, 25% rutile, 6% feldspar, 6% zircon sand, 12% ferrosilicon, 7% ferrotitanium, 7% ferroboron, 15% electrolytic manganese, 3% nickel powder, 5% potassium titanate, 4% magnesium powder, with the balance being Fe and unavoidable impurities.

9. The flux-cored welding wire for flat welding and fillet welding as described in claim 1, characterized in that: By weight percentage, the core comprises 1% fluoride, 20% rutile, 4.5% feldspar, 4.5% zircon sand, 10% ferrosilicon, 4.5% ferrotitanium, 5% ferroboron, 13% electrolytic manganese, 2% nickel powder, 3% potassium titanate, 3% magnesium powder, with the balance being Fe and unavoidable impurities.

10. The application of the flux-cored welding wire for flat welding and fillet welding as described in any one of claims 1-9, characterized in that: The flux-cored welding wire is used for welding primer-coated steel.

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