A flux-cored welding wire containing surface-aluminum-coated titanium carbide particles

Abstract

The present invention belongs to the field of welding materials, specifically a flux-cored wire containing surface-aluminum-plated titanium carbide particles. It includes an outer skin and a flux core, and the chemical composition and dosage of the flux core are calculated by mass percentage as follows: surface-aluminum-plated titanium carbide particles 8.0%-12.0%, aluminum powder 2.0%-3.0%, chromium powder, molybdenum powder and nickel powder 16%-20% in total, and the mass ratio of chromium powder, molybdenum powder and nickel powder is 52:96:59, ferrosilicon powder 3.0%-5.0%, ferromanganese powder 4.2%-5.8%, ferrovanadium powder 2.8%-4.0%, fluorite powder 3.2%-5.0%, rutile powder 2.8%-4.0%, calcium carbonate powder 3%-5%, and the rest is iron powder. The titanium atoms and iron atoms of the titanium carbide particles of the present invention form metallic bonds and produce a strong bond, and the time taken for the deposited metal to wear 0.5mm is increased to 1.5 times the original time, effectively improving the wear resistance of the deposited metal.

Description

Technical Field

[0001] The invention belongs to the technical field of welding materials, in particular to a flux-cored welding wire containing aluminum-plated titanium carbide particles on the surface. Background Art

[0002] Mining machinery, cement manufacturing equipment, coal production equipment, and other devices require critical components with excellent wear resistance to ensure a long service life. However, these wearable parts are generally large and wear quickly. Replacing them immediately after they have worn to a certain extent is costly and inefficient. Therefore, the industry often utilizes a process called overlay welding a layer of wear-resistant alloy onto the worn surface of these wearable parts to achieve repair and reuse, improving production efficiency and achieving good economic benefits.

[0003] To improve the wear resistance of the deposited metal during overlay welding, existing technologies often use flux-cored wire for overlay welding, and the flux-cored powder contains a hard phase (such as titanium carbide) to achieve the purpose of improving the wear resistance of the deposited metal. The current technical problem with this process is that during the production, transportation, storage, and use of the flux-cored wire, a certain oxide film will form on the surface of the titanium carbide particles and iron powder (the main component of the flux-cored wire). The titanium carbide particles will not melt during overlay welding. However, in the molten pool of the iron powder in the flux-cored wire and the base material, an oxidizing atmosphere will form between the titanium carbide particles and the iron atoms. Since the titanium carbide particles need a reducing atmosphere to bond with the iron atoms, the titanium carbide particles are not firmly bonded to the deposited metal after solidification, and the titanium carbide particles are easily detached during use, failing to achieve the intended wear resistance.

[0004] Some data show that after the surface of the hard phase (such as titanium carbide) is nickel-plated and then added to the flux core powder, during surfacing, the nickel atoms act as a "bridge", connecting with the titanium carbide particles on one side and the iron atoms in the deposited metal on the other side, which enhances the wettability of titanium carbide, thereby effectively improving the firmness of the bond between the titanium carbide particles and the deposited metal.

[0005] However, in actual production, it was found that the above technology was of little help in improving the firmness of the bond between titanium carbide particles and the deposited metal, and the improvement was limited. This was because relying on nickel atoms as a "bridge" to connect the titanium carbide particles and the deposited metal would inevitably form two chemical bonds (i.e., titanium-nickel and nickel-iron), making it impossible for the titanium carbide particles to be directly connected to the deposited metal. This weakened the connection strength between the titanium carbide particles and the deposited metal, causing the titanium carbide particles to easily fall off from the deposited metal. Summary of the Invention

[0006] The present invention provides a flux-cored welding wire containing surface-aluminum-plated titanium carbide particles, which solves the following technical problem: how to directly form chemical bonds between the titanium carbide particles and iron atoms in the deposited metal formed after the flux-cored welding wire is melted and solidified, so as to achieve the purpose of firmly bonding the titanium carbide particles to the deposited metal matrix.

[0007] The present invention adopts the following technical solutions:

[0008] A flux-cored welding wire containing surface-aluminum-coated titanium carbide particles comprises an outer sheath and a flux core. The chemical composition and usage of the flux core are as follows, by mass percentage: 8.0%-12.0% of surface-aluminum-coated titanium carbide particles, 2.0%-3.0% of aluminum powder, 16%-20% of chromium powder, molybdenum powder, and nickel powder in a total amount, wherein the mass ratio of the chromium powder, molybdenum powder, and nickel powder is 52:96:59, 3.0%-5.0% of ferrosilicon powder, 3.0%-5.0% of ferrosilicon powder, 4.2%-5.8% of ferromanganese powder, 2.8%-4.0% of ferrovanadium powder, 3.2%-5.0% of fluorite powder, 2.8%-4.0% of rutile powder, 3%-5% of calcium carbonate powder, and the balance is FHT100·25 reduced iron powder.

[0009] The surface aluminum-plated titanium carbide particles have titanium carbide particles inside and a uniform aluminum-plated layer outside, wherein the particle size of the internal titanium carbide particles is 50 μm-70 μm, and the thickness of the external aluminum-plated layer is 5 μm-10 μm.

[0010] The filling rate of the flux core is 30%-40%, that is, the mass of the flux core accounts for 30%-40% of the total mass of the flux-cored welding wire.

[0011] The 80 mesh passing rate of the aluminum powder, ferrosilicon powder, ferromanganese powder, ferrovanadium powder, fluorite powder, rutile powder, calcium carbonate powder, and FHT100.25 reduced iron powder is 100%, and the percentage is calculated by mass percentage.

[0012] The particle size of the chromium powder, molybdenum powder and nickel powder is 50 mesh to 80 mesh.

[0013] Preferably, the aluminum powder is FLPA280 brand in GB / T 2085.1-2007.

[0014] Preferably, the ferrosilicon powder is the PGFeSi75Al1.5 brand in GB / T 2272-2020.

[0015] Preferably, the ferromanganese powder is of the FeMn82C1.5 grade specified in GB / T 3795-2014.

[0016] Preferably, the ferrovanadium powder adopts the FeV50-A grade in GB / T 4139-2012.

[0017] The outer skin is made of cold-rolled steel strip, and the thickness of the cold-rolled steel strip is 0.3mm-1.2mm.

[0018] The diameter of the flux-cored welding wire is 2.4 mm to 8.0 mm.

[0019] The surface-aluminum-plated titanium carbide particles were prepared by the following method: using the technical solution of Chinese patent CN101210319B, the titanium carbide particles were first immersed in a mixed solution containing SnCl2 and PdCl2 for activation treatment, and then the titanium carbide particles were surface-chemically aluminum-plated according to the solution of Example 2 recorded in the patent.

[0020] The uniqueness of the present invention lies in two points:

[0021] (1) The surface of the titanium carbide particles added to the flux core is evenly coated with a layer of aluminum with strong reducing properties. During the welding process, the temperature of the liquid molten pool is extremely high, and the aluminum coating will quickly melt and react with the oxygen on the surface of the titanium carbide particles, consuming the oxygen and thus placing the titanium carbide particles and the iron atoms around them in a reducing atmosphere; the titanium atoms on the surface of the titanium carbide particles have coordinately unsaturated dangling bonds, and this special structure enables them to form a strong metallic bond with the iron atoms by sharing outer electrons. If the titanium carbide surface is not coated with aluminum, or is coated with nickel, or the aluminum content in the flux core powder is simply increased, then:

[0022] 1) If aluminum is not plated on the surface of the titanium carbide particles, titanium-oxygen bonds are easily formed on their surface. Since oxygen atoms have high electronegativity in the titanium-oxygen bond, they will seriously hinder the electron delocalization of the titanium atoms, hinder the formation of titanium-iron metal bonds, and make the titanium carbide particles easily fall off from the deposited metal matrix (see Comparative Example 1);

[0023] 2) When nickel is plated on the surface of titanium carbide particles, although the formation of titanium-oxygen bonds can be avoided, due to the weak reducing property of nickel, the oxygen in the molten pool will still create an oxidizing atmosphere between the titanium carbide particles and the iron atoms, hindering the formation of titanium-iron metallic bonds and making the titanium carbide particles easily fall off from the deposited metal matrix (see Comparative Example 2);

[0024] 3) Simply increasing the aluminum content in the flux core can only enhance the reducing atmosphere in the molten pool to a certain extent, but cannot meet the strict conditions for forming titanium-iron metallic bonds between titanium carbide particles and iron atoms, and will eventually cause titanium carbide particles to easily fall off from the deposited metal matrix (see Comparative Example 3);

[0025] (2) The ratio of chromium powder, molybdenum powder and nickel powder in the flux core powder is 52:96:59, which ensures that the ratio of the number of chromium atoms, molybdenum atoms and nickel atoms is 1:1:1. Chromium, molybdenum and nickel have more d electrons. When these elements are dissolved in the iron matrix, the electron cloud of the d orbital is more complex and directional, and will interact with the electron cloud of the iron atom. The d electrons will mix and overlap with the electron cloud of the iron atom to a certain extent, making the electron cloud distribution of the iron atom more diffuse, promoting the electrons to approach the titanium atoms on the surface of the titanium carbide particles, and increasing the tendency of the iron atoms to form metallic bonds with the titanium atoms. When the ratio of the number is 1:1:1, it is easier to form a strong metallic bond; otherwise, titanium and iron are not easy to combine, which will eventually cause the titanium carbide particles to fall off from the deposited metal matrix (see Comparative Example 4).

[0026] The present invention has the following beneficial technical effects:

[0027] Using aluminum-plated titanium carbide particles (the first condition) and maintaining a ratio of chromium powder, molybdenum powder, and nickel powder of 52:96:59 (the second condition) creates coordinatively unsaturated dangling bonds in the titanium atoms on the titanium carbide particle surface. This allows the d electrons of chromium, molybdenum, and nickel (which have a higher number of d electrons) to mix and overlap to a certain extent with the electron cloud of iron atoms, making the iron electron cloud more diffuse and encouraging electrons to approach the titanium atoms on the titanium carbide particle surface. These two conditions work together to form a strong metallic bond between the iron and titanium atoms, making the titanium carbide particles less likely to detach from the deposited metal matrix. Wearing a 0.5mm layer of deposited metal takes approximately 1.5 times longer than when these two conditions are not used, effectively improving the wear resistance of the deposited metal. DETAILED DESCRIPTION

[0028] The principles and features of the present invention are described below in conjunction with embodiments and comparative examples. The enumerated embodiments and comparative examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0029] Example 1

[0030] A flux-cored welding wire containing surface-aluminum-coated titanium carbide particles comprises an outer sheath and a flux core. The chemical composition and usage of the flux core are, by mass percentage, as follows: 8.0% surface-aluminum-coated titanium carbide particles, 2.0% aluminum powder, 16% in total of chromium powder, molybdenum powder, and nickel powder, wherein the mass ratio of the chromium powder, molybdenum powder, and nickel powder is 52:96:59, 3.0% ferrosilicon powder, 4.2% ferromanganese powder, 2.8% ferrovanadium powder, 3.2% fluorite powder, 2.8% rutile powder, 3% calcium carbonate powder, and the balance is FHT100·25 reduced iron powder.

[0031] The surface-aluminum-plated titanium carbide particles have titanium carbide particles inside and a uniform aluminum-plated layer outside, wherein the particle size of the internal titanium carbide particles is 50μm-70μm, and the thickness of the external aluminum-plated layer is 5μm-10μm;

[0032] Surface-aluminum-plated titanium carbide particles were prepared by the following method: using the technical solution of Chinese patent CN101210319B, the titanium carbide particles were first immersed in a mixed solution containing SnCl2 and PdCl2 for activation treatment, and then the surface of the titanium carbide particles was chemically aluminum-plated according to the technical solution of Example 2.

[0033] The filling rate of the drug core is 30%.

[0034] The aluminum powder adopts the FLPA280 brand in GB / T 2085.1-2007; the ferrosilicon powder adopts the PGFeSi75Al1.5 brand in GB / T 2272-2020; the ferromanganese powder adopts the FeMn82C1.5 brand in GB / T 3795-2014; and the ferrovanadium powder adopts the FeV50-A brand in GB / T4139-2012.

[0035] The 80-mesh pass rate of aluminum powder, ferrosilicon powder, ferromanganese powder, ferrovanadium powder, fluorite powder and FHT100·25 reduced iron powder is 100%.

[0036] The particle size of chromium powder, molybdenum powder and nickel powder is 50 mesh to 80 mesh.

[0037] The outer skin is made of cold-rolled steel strip, and the thickness of the cold-rolled steel strip is 0.3 mm.

[0038] The diameter of the flux-cored wire is 2.4 mm.

[0039] Example 2

[0040] A flux-cored welding wire containing surface-aluminum-coated titanium carbide particles comprises an outer sheath and a flux core. The chemical composition and usage of the flux core are as follows, by mass percentage: 12.0% surface-aluminum-coated titanium carbide particles, 3.0% aluminum powder, 20% in total of chromium powder, molybdenum powder, and nickel powder, wherein the mass ratio of the chromium powder, molybdenum powder, and nickel powder is 52:96:59, 5.0% ferrosilicon powder, 5.8% ferromanganese powder, 4.0% ferrovanadium powder, 5.0% fluorite powder, 4.0% rutile powder, 5% calcium carbonate powder, and the balance is FHT100·25 reduced iron powder.

[0041] The surface-aluminum-plated titanium carbide particles have titanium carbide particles inside and a uniform aluminum-plated layer outside, wherein the particle size of the internal titanium carbide particles is 50μm-70μm, and the thickness of the external aluminum-plated layer is 5μm-10μm;

[0042] Surface-aluminum-coated titanium carbide particles were prepared as described in Example 1 of the present invention.

[0043] The filling rate of the core is 35%.

[0044] The aluminum powder adopts the FLPA280 brand in GB / T 2085.1-2007; the ferrosilicon powder adopts the PGFeSi75Al1.5 brand in GB / T 2272-2020; the ferromanganese powder adopts the FeMn82C1.5 brand in GB / T 3795-2014; and the ferrovanadium powder adopts the FeV50-A brand in GB / T4139-2012.

[0045] The 80-mesh pass rate of aluminum powder, ferrosilicon powder, ferromanganese powder, ferrovanadium powder, fluorite powder and FHT100·25 reduced iron powder is 100%.

[0046] The particle size of chromium powder, molybdenum powder and nickel powder is 50 mesh to 80 mesh.

[0047] The outer skin is made of H08A cold-rolled steel strip, and the thickness of the H08A cold-rolled steel strip is 0.8 mm.

[0048] The diameter of the flux-cored wire is 6.0 mm.

[0049] Example 3

[0050] A flux-cored welding wire containing surface-aluminum-coated titanium carbide particles comprises an outer sheath and a flux core. The chemical composition and dosage of the flux core are, by mass percentage, as follows: 10.0% surface-aluminum-coated titanium carbide particles, 2.5% aluminum powder, 18% in total of chromium powder, molybdenum powder, and nickel powder, wherein the mass ratio of the chromium powder, molybdenum powder, and nickel powder is 52:96:59, 4.0% ferrosilicon powder, 5.0% ferromanganese powder, 3.4% ferrovanadium powder, 4.1% fluorite powder, 3.4% rutile powder, 4% calcium carbonate powder, and the balance is FHT100·25 reduced iron powder.

[0051] The surface-aluminum-plated titanium carbide particles have titanium carbide particles inside and a uniform aluminum-plated layer outside, wherein the particle size of the internal titanium carbide particles is 50μm-70μm, and the thickness of the external aluminum-plated layer is 5μm-10μm;

[0052] Surface-aluminum-coated titanium carbide particles were prepared as described in Example 1 of the present invention.

[0053] The filling rate of the core is 40%.

[0054] The aluminum powder is FLPA280 in GB / T 2085.1-2007; the ferrosilicon powder is PGFeSi75Al1.5 in GB / T 2272-2020; the ferromanganese powder is FeMn82C1.5 in GB / T 3795-2014; and the ferrovanadium powder is FeV50-A in GB / T4139-2012.

[0055] The 80-mesh pass rate of aluminum powder, ferrosilicon powder, ferromanganese powder, ferrovanadium powder, fluorite powder and FHT100·25 reduced iron powder is 100%.

[0056] The particle size of chromium powder, molybdenum powder and nickel powder is 50 mesh to 80 mesh.

[0057] The outer skin is made of cold-rolled steel strip, and the thickness of the cold-rolled steel strip is 1.2 mm.

[0058] The diameter of the flux-cored wire is 8.0 mm.

[0059] Comparative Example 1:

[0060] The method is basically the same as Example 3, except that the surface of the titanium carbide particles in the core chemical composition is not coated with aluminum.

[0061] Comparative Example 2:

[0062] The method is basically the same as Example 3, except that the surface of the titanium carbide particles in the core chemical composition is electrolessly nickel-plated.

[0063] Comparative Example 3:

[0064] The method is basically the same as Example 3, except that the surface of the titanium carbide particles in the core chemical composition is not coated with aluminum, but the content of aluminum powder in the core is increased to 8%.

[0065] Comparative Example 4:

[0066] It is basically the same as Example 3, except that the mass ratio of chromium powder, molybdenum powder and nickel powder in the chemical composition of the core is 104:144:236, and the number ratio of chromium atoms, molybdenum atoms and nickel atoms is 2:3:4.

[0067] Flux-cored welding wires prepared in Examples 1, 2, and 3 and Comparative Examples 1, 2, 3, and 4 were used to buildup welds on Q235 sheet metal, depositing a metal layer approximately 3 mm thick. The average hardness of the deposited metal after buildup was measured, and wear testing was performed, measuring the time required to achieve 0.5 mm wear. Five experiments were conducted for each of the Examples and Comparative Examples, and the average of the five results was calculated. The results are shown in Table 1.

[0068]

[0069] It can be seen from the above embodiments and comparative examples that when the surface of the titanium carbide particles in the flux-cored welding wire is not aluminum-plated, or the surface is nickel-plated, or the surface of the titanium carbide particles is not aluminum-plated but the aluminum content in the flux core powder is increased, or the ratio of chromium powder, molybdenum powder, and nickel powder is not 52:96:59, the hardness of the deposited metal is not much different, but the time taken to wear 0.5 mm is greatly reduced, indicating that the titanium carbide particles are not firmly bonded to the deposited metal matrix and are easy to fall off; when the surface of the titanium carbide particles is aluminum-plated and the ratio of chromium powder, molybdenum powder, and nickel powder is 52:96:59, the titanium carbide particles are firmly bonded to the deposited metal matrix, are not easy to fall off, have good wear resistance, and the time taken to wear 0.5 mm of the deposited metal layer is increased to about 1.5 times the original time.

[0070] All equivalent changes or modifications made based on the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A flux-cored welding wire containing surface-aluminum-plated titanium carbide particles, comprising an outer sheath and a flux core, characterized in that: The chemical composition and dosage of the flux core are as follows by mass percentage: 8.0%-12.0% of surface-aluminum-plated titanium carbide particles, 2.0%-3.0% of aluminum powder, 16%-20% of chromium powder, molybdenum powder and nickel powder in a total weight ratio of 52:96:59, 3.0%-5.0% of ferrosilicon powder, 4.2%-5.8% of ferromanganese powder, 2.8%-4.0% of ferrovanadium powder, 3.2%-5.0% of fluorite powder, 2.8%-4.0% of rutile powder, 3%-5% of calcium carbonate powder, and the balance is FHT100·25 reduced iron powder; The surface aluminum-plated titanium carbide particles have titanium carbide particles inside and a uniform aluminum-plated layer outside, wherein the particle size of the internal titanium carbide particles is 50 μm-70 μm, and the thickness of the external aluminum-plated layer is 5 μm-10 μm.

2. The flux-cored welding wire containing surface-aluminum-plated titanium carbide particles according to claim 1, characterized in that: The brand of the aluminum powder is FLPA280, the brand of the ferrosilicon powder is PGFeSi75Al1.5, the brand of the ferromanganese powder is FeMn82C1.5, and the brand of the ferrovanadium powder is FeV50-A.

3. The flux-cored welding wire containing surface-aluminum-plated titanium carbide particles according to claim 1, characterized in that: The 80-mesh pass rate of the aluminum powder, ferrosilicon powder, ferromanganese powder, ferrovanadium powder, fluorite powder, rutile powder, calcium carbonate powder, and FHT100.25 reduced iron powder is 100%.

4. The flux-cored welding wire containing surface-aluminum-plated titanium carbide particles according to claim 1, characterized in that: The particle size of the chromium powder, molybdenum powder and nickel powder is 50 mesh to 80 mesh.

5. The flux-cored welding wire containing surface-aluminum-plated titanium carbide particles according to claim 1, characterized in that: The filling rate of the drug core is 30%-40%.

6. The flux-cored welding wire containing surface-aluminum-plated titanium carbide particles according to claim 1, characterized in that: The outer skin is made of cold-rolled steel strip, and the thickness of the cold-rolled steel strip is 0.3mm-1.2mm.

7. The flux-cored welding wire containing surface-aluminum-plated titanium carbide particles according to claim 1, characterized in that: The diameter of the flux-cored welding wire is 2.4 mm to 8.0 mm.

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