A cored wire for hardfacing repair and a method for manufacturing the same

Abstract

The present application relates to the technical field of welding, and proposes a flux-cored wire for overlaying repair and a preparation method thereof.The flux-cored wire for overlaying repair comprises a core and a sheath, and the raw material of the core comprises the following components in parts by weight: 8-12 parts of aluminum powder, 2-5 parts of feldspar, 4-8 parts of silicon manganese, 10-17 parts of ferromolybdenum, 12-16 parts of ferrochrome, 8-14 parts of reinforcing agent, and 20-26 parts of iron powder; the reinforcing agent comprises sodium fluoroborate, rare earth fluoride and tungsten carbide.Through the above technical solution, the problem of low tensile strength of deposited metal in the related art is solved.

Description

Technical Field

[0001] This invention relates to the field of welding technology, specifically to a flux-cored welding wire for surfacing repair and its preparation method. Background Technology

[0002] In modern industrial systems, the stable operation of machinery and equipment plays a decisive role in production efficiency and product quality. However, in actual operation, various types of equipment inevitably face complex, variable, and harsh working environments, which puts critical components under tremendous pressure and makes them prone to problems such as wear, corrosion, and fatigue damage.

[0003] Taking the energy extraction industry as an example, oil drilling rigs operate for extended periods in underground environments characterized by high temperatures, high pressures, and corrosive mud. Each drilling operation involves intense friction between the drill rod and the rock, as well as erosion from the mud, resulting in severe wear on the drill rod surface and a significantly shortened service life. In areas with harsh mining conditions, frequent drill rod maintenance or replacement not only increases extraction costs but also frequently leads to operational interruptions. In the steel smelting sector, the lining inside blast furnaces is subjected to constant scouring by molten iron and erosion by slag. Frequent spalling and erosion of the lining material not only affect the normal production cycle of the blast furnace but can also cause safety accidents due to lining damage.

[0004] To address these issues, weld overlay repair technology has emerged as a highly promising solution. By depositing specific welding materials onto the surface of damaged parts, it not only restores the original dimensions of the components but also imparts improved wear resistance and corrosion resistance. However, traditional weld overlay repair technology has significant limitations. In the automotive manufacturing industry, while some high-precision stamping dies can have their dimensions restored after traditional weld overlay repair, the insufficient tensile strength of the deposited metal makes the die surface prone to micro-cracks during subsequent high-intensity stamping operations, affecting the precision and quality of the stamped parts. Similarly, in shipbuilding, propellers, as critical components for ship propulsion, operate under high loads in seawater environments for extended periods. Propellers repaired using traditional weld overlay repair often lack the tensile strength required for long-distance ocean voyages, making them susceptible to blade deformation or even breakage during navigation, seriously threatening ship safety.

[0005] With the rise of emerging industries such as intelligent manufacturing and high-end equipment manufacturing, the performance requirements for mechanical equipment have reached unprecedented levels. Whether it's precision machining equipment or large heavy-duty machinery, components need to possess higher strength and stability. Against this backdrop, the development of a flux-cored welding wire technology for weld overlay repair that can significantly improve the tensile strength of the deposited metal is urgently needed. Summary of the Invention

[0006] This invention proposes a flux-cored welding wire for weld overlay repair and its preparation method, which solves the problem of low tensile strength of the deposited metal in flux-cored welding wires for weld overlay repair in related technologies.

[0007] The technical solution of the present invention is as follows: This invention proposes a flux-cored welding wire for surfacing repair, comprising a flux core and an outer sheath. The raw materials of the flux core include the following components in parts by weight: 8-12 parts aluminum powder, 2-5 parts feldspar, 4-8 parts ferrosilicon manganese, 10-17 parts ferromolybdenum, 12-16 parts ferrochrome, 8-14 parts reinforcing agent, and 20-26 parts iron powder. The reinforcing agents include sodium fluoroborate, rare earth fluorides, and tungsten carbide.

[0008] As a further technical solution, the mass ratio of sodium fluoroborate, rare earth fluoride and tungsten carbide is 3~5:6:11.

[0009] In this invention, by adjusting the mass ratio of sodium fluoroborate, rare earth fluoride, and tungsten carbide to 3~5:6:11, the tensile strength of the deposited metal is further improved.

[0010] As a further technical solution, the mass ratio of sodium fluoroborate, rare earth fluoride and tungsten carbide is 4:6:11.

[0011] In this invention, by adjusting the mass ratio of sodium fluoroborate, rare earth fluoride, and tungsten carbide to 4:6:11, the tensile strength of the deposited metal is further improved.

[0012] As a further technical solution, the rare earth fluoride includes one or more of lanthanum fluoride, cerium fluoride, and yttrium fluoride.

[0013] As a further technical solution, the particle size of the tungsten carbide is 100~200nm.

[0014] This invention improves the yield strength of the fused metal by controlling the particle size of tungsten carbide to 100~200nm.

[0015] As a further technical solution, the outer skin is made of steel, which is composed of the following elements by weight percentage: carbon 0.05%~0.08%, manganese 0.40%~0.70%, silicon 0.03%~0.05%, chromium 0.32%~0.44%, sulfur 0.0008%~0.012%, phosphorus 0.0002%~0.015%, with the balance being iron and unavoidable impurities.

[0016] As a further technical solution, the mass ratio of the core to the outer sheath is 1.5~2.5:7.

[0017] This invention also proposes a method for preparing a flux-cored welding wire for weld overlay repair, comprising the following steps: S1. Ball mill all components except the core enhancer, add the enhancer, mix until uniform, and dry to obtain core powder; S2. Roll the steel into a U-shaped groove, add the flux-cored powder into the U-shaped groove, seal the end, reduce the diameter, and draw the wire to obtain flux-cored welding wire for overlay repair.

[0018] As a further technical solution, the ball milling process is carried out at a rotation speed of 200-300 rpm for 3-4 hours.

[0019] As a further technical solution, the drying process is carried out at a temperature of 800~900℃ for 8~12 hours.

[0020] As a further technical solution, the diameter of the flux-cored welding wire used for weld overlay repair is 1.5~3mm.

[0021] The working principle and beneficial effects of this invention are as follows: In this invention, sodium fluoroborate, rare earth fluorides, and tungsten carbide are added as reinforcing agents. Sodium fluoroborate and rare earth fluorides decompose into fluorine during welding, which forms hydrogen fluoride with hydrogen in the weld, thus improving the performance of the weld overlay. Tungsten carbide is a hard phase with high hardness. The synergistic effect of sodium fluoroborate, rare earth fluorides, and tungsten carbide improves the tensile strength of the weld metal deposited by the flux-cored wire used for weld overlay repair. Detailed Implementation

[0022] 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.

[0023] In the following examples and comparative examples, the sodium fluoroborate had a particle size of 100 mesh and a purity of 99 wt%; the lanthanum fluoride had a particle size of 8 μm and a purity of 99.99 wt%; the cerium fluoride was purchased from Shandong Xinghai Chemical Co., Ltd., product number XH-181; the yttrium fluoride had a purity of 99.99 wt%; the tungsten carbide with a particle size of 50 nm had a purity of 99.9 wt%; the tungsten carbide with a particle size of 100 nm had a purity of 99.9 wt%; the tungsten carbide with a particle size of 200 nm had a purity of 99.9 wt%; the tungsten carbide with a particle size of 300 nm had a purity of 99.9 wt%; the silicon content in the ferrosilicon manganese was 17 wt%; the molybdenum content in the ferromolybdenum was 60 wt%; the chromium content in the ferrochrome was 65.1 wt%; and the iron powder had a purity of 99 wt%.

[0024] Example 1 A flux-cored welding wire for surfacing repair includes a flux core and an outer sheath in a mass ratio of 2.5:7. The raw materials of the flux core include the following components in parts by weight: 12 parts aluminum powder, 5 parts feldspar, 8 parts silicon manganese, 17 parts ferromolybdenum, 16 parts ferrochrome, 14 parts reinforcing agent, and 26 parts iron powder. The reinforcing agents include sodium fluoroborate, lanthanum fluoride, and tungsten carbide in a mass ratio of 8:6:11; The particle size of tungsten carbide is 300 nm; The outer casing is made of steel, which is composed of the following elements by weight percentage: carbon 0.08%, manganese 0.70%, silicon 0.05%, chromium 0.44%, sulfur 0.012%, phosphorus 0.015%, with the balance being iron and unavoidable impurities. The preparation method of flux-cored welding wire for weld overlay repair includes the following steps: S1. Ball mill all components except the core enhancer at 300 rpm for 3 hours, add the enhancer, mix until uniform, and dry at 900℃ for 8 hours to obtain core powder; S2. Roll the steel into a U-shaped groove, add flux-cored powder into the U-shaped groove, seal the end, reduce the diameter, and draw the wire to obtain a flux-cored welding wire with a diameter of 3mm for overlay repair.

[0025] Example 2 A flux-cored welding wire for surfacing repair includes a flux core and an outer sheath in a mass ratio of 1.5:7. The raw materials of the flux core include the following components in parts by weight: 8 parts aluminum powder, 2 parts feldspar, 4 parts ferrosilicon manganese, 10 parts ferromolybdenum, 12 parts ferrochrome, 8 parts reinforcing agent, and 20 parts iron powder. The reinforcing agents include sodium fluoroborate, cerium fluoride, and tungsten carbide in a mass ratio of 1:6:11; The particle size of tungsten carbide is 300 nm; The outer casing is made of steel, which is composed of the following elements by weight percentage: carbon 0.05%, manganese 0.40%, silicon 0.03%, chromium 0.32%, sulfur 0.0008%, phosphorus 0.0002%, with the balance being iron and unavoidable impurities; The preparation method of flux-cored welding wire for weld overlay repair includes the following steps: S1. Ball mill all components except the core enhancer at 200 rpm for 4 hours, add the enhancer, mix until uniform, and dry at 800℃ for 12 hours to obtain core powder; S2. Roll the steel into a U-shaped groove, add flux-cored powder into the U-shaped groove, seal the end, reduce the diameter, and draw the wire to obtain a flux-cored welding wire with a diameter of 1.5mm for overlay welding repair.

[0026] Example 3 A flux-cored welding wire for surfacing repair includes a flux core and an outer sheath. The raw materials of the flux core include the following components in parts by weight: 10 parts aluminum powder, 4 parts feldspar, 6 parts ferrosilicon manganese, 15 parts ferromolybdenum, 14 parts ferrochrome, 12 parts reinforcing agent, and 24 parts iron powder. The reinforcing agents include sodium fluoroborate, yttrium fluoride, and tungsten carbide in a mass ratio of 6:6:11; The particle size of tungsten carbide is 300 nm; The outer casing is made of steel, which is composed of the following elements by weight percentage: 0.06% carbon, 0.50% manganese, 0.04% silicon, 0.38% chromium, 0.001% sulfur, 0.0015% phosphorus, with the balance being iron and unavoidable impurities. The mass ratio of the core to the outer sheath is 2:7; The preparation method of flux-cored welding wire for weld overlay repair includes the following steps: S1. Ball mill all components except the core enhancer at 250 rpm for 3.5 h, add the enhancer, mix until uniform, and dry at 850 ℃ for 10 h to obtain core powder; S2. Roll the steel into a U-shaped groove, add flux-cored powder into the U-shaped groove, seal the end, reduce the diameter, and draw the wire to obtain a flux-cored welding wire with a diameter of 2mm for overlay welding repair.

[0027] Example 4 The only difference between this embodiment and Embodiment 3 is that the reinforcing agent in this embodiment includes sodium fluoroborate, yttrium fluoride, and tungsten carbide in a mass ratio of 2:6:11.

[0028] Example 5 The only difference between this embodiment and Embodiment 3 is that the reinforcing agent in this embodiment includes sodium fluoroborate, yttrium fluoride, and tungsten carbide in a mass ratio of 3:6:11.

[0029] Example 6 The only difference between this embodiment and Embodiment 3 is that the reinforcing agent in this embodiment includes sodium fluoroborate, yttrium fluoride, and tungsten carbide in a mass ratio of 4:6:11.

[0030] Example 7 The only difference between this embodiment and Embodiment 3 is that the reinforcing agent in this embodiment includes sodium fluoroborate, yttrium fluoride, and tungsten carbide in a mass ratio of 5:6:11.

[0031] Example 8 The only difference between this embodiment and Embodiment 6 is that the particle size of tungsten carbide in this embodiment is 50 nm.

[0032] Example 9 The only difference between this embodiment and Embodiment 6 is that the particle size of tungsten carbide in this embodiment is 100 nm.

[0033] Example 10 The only difference between this embodiment and Embodiment 6 is that the particle size of tungsten carbide in this embodiment is 200 nm.

[0034] Comparative Example 1 The only difference between this comparative example and Example 3 is that the reinforcing agent in this comparative example is a 1:1 mixture of sodium fluoroborate and yttrium fluoride.

[0035] Comparative Example 2 The only difference between this comparative example and Example 3 is that the reinforcing agent in this comparative example is sodium fluoroborate and tungsten carbide in a 6:11 ratio.

[0036] Comparative Example 3 The only difference between this comparative example and Example 3 is that the reinforcing agent in this comparative example is yttrium fluoride and tungsten carbide in a 6:11 ratio.

[0037] Comparative Example 4 The only difference between this comparative example and Example 3 is that this comparative example does not contain any reinforcing agent.

[0038] Experimental Example 1 The flux-cored welding wires for weld overlay repair prepared in Examples 1-7 and Comparative Examples 1-4 were used for butt joint welding of T22 pearlitic heat-resistant steel. The welding current was 250A, the welding voltage was 28A, the shielding gas was argon, and the gas flow rate was 5L / min. The tensile strength of the deposited metal was tested according to the method specified in GB / T 2652-2022 "Destructive Testing of Welds in Metallic Materials - Longitudinal Tensile Test of Weld Metal in Fusion Welded Joints". The test results are shown in Table 1.

[0039] Table 1 Tensile strength test results

[0040] Comparing Examples 3-7 with Comparative Examples 1-4, it is evident that the synergistic effect of sodium fluoroborate, rare earth fluorides, and tungsten carbide in this invention improves the tensile strength of the deposited metal.

[0041] Experiment Example 2 The flux-cored welding wires for weld overlay repair prepared in Examples 6, 8-10 were used for butt joint welding of T22 pearlitic heat-resistant steel. The welding current was 250A, the welding voltage was 28A, the shielding gas was argon, and the gas flow rate was 5L / min. The yield strength of the deposited metal was tested according to the method specified in GB / T 2652-2022 "Destructive Testing of Welds in Metallic Materials - Longitudinal Tensile Test of Weld Metal in Fusion Welded Joints". The test results are shown in Table 2.

[0042] Table 2 Yield Strength Test Results

[0043] Comparing Examples 9 and 10 with Examples 6 and 8, it is shown that adjusting the tungsten carbide particle size to 100-200 nm increases the yield strength of the deposited metal.

[0044] Experimental Example 3 The flux-cored welding wire for weld overlay repair prepared in Example 3 was used for butt joint welding of T22 pearlitic heat-resistant steel. The welding current was 250A, the welding voltage was 28A, the shielding gas was argon, and the gas flow rate was 5L / min. The impact absorption energy of the deposited metal was tested at room temperature according to the method specified in GB / T 229-2020 "Metallic Materials Charpy Pendulum Impact Test Method", with a V-notch. The test results are shown in Table 3.

[0045] Table 3 Results of Energy Absorption Test

[0046] As shown in Table 3, the flux-cored welding wire for weld overlay repair in this invention is suitable for weld overlay repair.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flux-cored welding wire for weld overlay repair, characterized in that, It includes a core and an outer sheath. The raw materials of the core are composed of the following components in parts by weight: 8-12 parts aluminum powder, 2-5 parts feldspar, 4-8 parts ferrosilicon, 10-17 parts ferromolybdenum, 12-16 parts ferrochrome, 8-14 parts reinforcing agent, and 20-26 parts iron powder. The reinforcing agent is sodium fluoroborate, rare earth fluorides, and tungsten carbide; The mass ratio of sodium fluoroborate, rare earth fluoride and tungsten carbide is 4:6:11; The tungsten carbide has a particle size of 100~200nm; The rare earth fluoride is one or more of lanthanum fluoride, cerium fluoride, and yttrium fluoride.

2. The flux-cored welding wire for weld overlay repair according to claim 1, characterized in that, The outer skin is made of steel, which is composed of the following elements by weight percentage: carbon 0.05%~0.08%, manganese 0.40%~0.70%, silicon 0.03%~0.05%, chromium 0.32%~0.44%, sulfur 0.0008%~0.012%, phosphorus 0.0002%~0.015%, with the balance being iron and unavoidable impurities.

3. The flux-cored welding wire for weld overlay repair according to claim 1, characterized in that, The mass ratio of the core to the outer sheath is 1.5~2.5:

7.

4. A method for preparing a flux-cored welding wire for weld overlay repair, used to prepare the flux-cored welding wire for weld overlay repair as described in claim 1, characterized in that, Includes the following steps: S1. Ball mill all components of the core except for the reinforcing agent, add the reinforcing agent, mix until uniform, and dry to obtain core powder; S2. Roll the steel into a U-shaped groove, add the flux-cored powder into the U-shaped groove, seal the end, reduce the diameter, and draw the wire to obtain flux-cored welding wire for overlay repair.

5. The method for preparing a flux-cored welding wire for weld overlay repair according to claim 4, characterized in that, The drying process is carried out at a temperature of 800-900℃ for 8-12 hours.

6. The method for preparing a flux-cored welding wire for weld overlay repair according to claim 4, characterized in that, The diameter of the flux-cored welding wire used for the weld overlay repair is 1.5~3mm.

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