High-hardness cobalt-based alloy welding wire and preparation method thereof

Abstract

The invention provides a high-hardness cobalt-based alloy welding wire and a preparation method thereof, and the high-hardness cobalt-based alloy welding wire comprises the following components in percentage by mass: less than or equal to 0.5% of C, 3-4% of Si, 15-20% of Cr, 1-4% of Ni, 25-30% of Mo, 45-55% of Co, less than or equal to 1% of Fe, less than or equal to 0.02% of La, less than or equal to 0.02% of B, less than or equal to 0.01% of S and less than or equal to 0.01% of P. According to the cobalt-based welding wire, through regulation and control of alloy elements, the hardness of the cobalt-based welding wire is remarkably improved, the uniformity of components of the welding wire is improved, the welding strength is improved, the size of the welding wire is extremely thin, and the welding manufacturability of the welding wire is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of welding and relates to a welding wire, in particular to a high-hardness cobalt-based alloy welding wire and a preparation method thereof. Background Art

[0002] Cobalt-based welding wire is a special alloy material that has received widespread attention in high-performance welding applications in recent years. Cobalt-based alloys possess excellent resistance to high temperatures, thermal fatigue, corrosion, and wear, and are widely used in aerospace, metallurgy, chemical engineering, and machinery manufacturing. Cobalt-based alloys are particularly well-suited for the manufacture and repair of critical components, such as aircraft engine turbine blades, gas turbine hot-end components, and high-temperature valves, that operate under extreme conditions of high temperature, high pressure, severe wear, and corrosive media. Using cobalt-based welding wire to repair damaged components and perform surface hardfacing and other processes can improve the components' corrosion and heat resistance, thereby extending their service life.

[0003] However, cobalt-based welding wire currently faces several technical bottlenecks in practical applications. Cobalt-based welding wire contains a high content of cobalt, and generally lacks good deformation processing capabilities. Traditional manufacturing processes are prone to internal defects during production, and the wire diameter is typically large, with an uneven surface, making it difficult to meet the precision requirements in certain precision welding processes. Furthermore, cobalt-based alloys are highly sensitive to impurity elements, and the casting process is relatively complex, making it prone to the introduction of harmful impurities, uneven distribution of alloying elements, and element segregation. This significantly reduces the alloy's hardness and overall mechanical properties, and further deteriorates the wire's weldability.

[0004] For example, CN113275788A discloses a highly wear-resistant alloy welding wire for welding cobalt-based composite materials, its preparation method, and its application. The chemical composition of the welding wire includes: C 0.01-1.2%, Cr 18-34%, Ni 0.5-10%, W 5-24%, V 0.5-6%, Fe 1-10%, B 0.01-0.05%, and the balance Co. This welding wire improves weldability by increasing the B content and reducing the contents of elements such as W and C. It is manufactured using wire-cut machining. CN112643245A discloses a cobalt-based alloy welding wire for high-temperature alloy welding, its preparation method, and its application. The chemical composition includes: C 0.01-1.2%, Cr 15.0-35.0%, Ni 6.5-20.5%, W 5.5-10.5%, Mo 0.1-2.5%, Al 0.1-6.5%, Ti 0.01-0.1%, Fe 0-3.0%, Ta 0.01-0.8%, B 0.01-0.05%, Zr 0.01-0.8%, and Co as the balance. This welding wire improves weldability by increasing Mo and reducing Al, Ti, B, and C. However, existing cobalt-based welding wires have low hardness and a large diameter, making them less suitable for more precise welding processes.

[0005] Therefore, the development of cobalt-based welding wire with uniform composition, high strength and excellent welding performance is of great significance to meet the needs of high-end equipment manufacturing and repair. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-hardness cobalt-based alloy welding wire and a preparation method thereof, thereby increasing the hardness of the cobalt-based welding wire and improving its welding processability.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a high-hardness cobalt-based alloy welding wire, wherein the composition of the high-hardness cobalt-based alloy welding wire, measured by mass percentage, comprises:

[0009] C≤0.5%, Si 3%-4%, Cr 15%-20%, Ni 1%-4%, Mo 25%-30%, Co 45%-55%, Fe≤1%, La≤0.02%, B≤0.02%, S≤0.01%, P≤0.01%.

[0010] The cobalt-based alloy welding wire provided by the present invention significantly improves the hardness of the cobalt-based welding wire through the regulation of alloying elements. The welding wire composition is uniform, segregation is not generated, and the content of impurity elements is controlled to be extremely low, thereby improving the welding processability and welding strength of the welding wire.

[0011] Carbon is one of the main elements in weld metal, ensuring weld metal strength. It can form carbides with Cr and Mo in the welding wire, thereby increasing the wire's hardness and weld strength. However, excessive carbon content can easily cause weld spatter, affecting the wire's processing performance. It can also easily form continuous carbides at grain boundaries, increasing the risk of hot cracking during welding.

[0012] In the present invention, the C content in the welding wire is controlled to be ≤0.5%, for example, it can be 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.32%, 0.35%, 0.38%, 0.4%, 0.42%, 0.45%, 0.48% or 0.5%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 0.3%-0.5%.

[0013] Si is a deoxidizing and solid solution strengthening element that increases weld strength, improves weld pool fluidity, reduces lack of fusion and undercut defects, and inhibits element burnout. The welding wire of this invention has an increased Si content, improving weldability. However, excessive Si content may increase brittleness, reduce weld toughness, and increase the tendency to hot cracking.

[0014] In the present invention, the Si content in the welding wire is controlled within a range of 3%-4%, for example, 3%, 3.2%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9% or 4%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 3.6%-4%.

[0015] Cr is a corrosion-resistant element that can form a passivation film to improve the corrosion resistance of the weld. At the same time, it can form carbides with C and Mo to increase the hardness of the welding wire and the strength of the weld. However, too high a chromium content will precipitate a brittle phase and reduce the toughness of the weld.

[0016] In the present invention, the Cr content in the welding wire is controlled within a range of 15% to 20%, for example, 15%, 16%, 16.5%, 17%, 17.5%, 18%, 19% or 20%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 16% to 18%.

[0017] The nickel element can produce a solid solution strengthening effect and play a role in matrix stabilization, which can inhibit the transformation of the cobalt matrix into a brittle phase. However, if the nickel content is too high, it will inhibit the formation and precipitation of carbides, reducing the hardness and wear resistance of the welding wire.

[0018] In the present invention, the Ni content in the welding wire is controlled within a range of 1% to 4%, for example, 1%, 1.5%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.5% or 4%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 2% to 3%.

[0019] Mo is a carbide-forming element that forms a hard molybdenum carbide phase, significantly improving the hardness and wear resistance of the welding wire. It also produces a solid solution strengthening effect, controlling dislocation motion. Increasing the molybdenum content in the present invention can form a Laves phase, further improving weld strength.

[0020] In the present invention, the Mo content in the welding wire is controlled to be 25%-30%, for example, it can be 25%, 26%, 27%, 28%, 28.5%, 29%, 29.5% or 30%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 28%-30%.

[0021] Co is a matrix element that has high temperature stability and extremely high corrosion resistance and wear resistance.

[0022] In the present invention, the Co content in the welding wire is controlled within a range of 45% to 55%, for example, it may be 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54% or 55%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 45% to 50%.

[0023] The Fe element in the welding wire helps to improve the smelting processability of the alloy, but too high an iron content can easily cause precipitation of impurity phases.

[0024] In the present invention, the Fe content in the welding wire is controlled to be ≤1%, for example, it can be 0.01%, 0.05%, 0.1%, 0.3%, 0.5%, 0.8% or 1%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 0.1%-1%.

[0025] La can fix sulfur and play a role in deep desulfurization. At the same time, it can refine the grains, inhibit the growth of columnar crystals, reduce thermal cracks, and improve welding strength.

[0026] In the present invention, the La content in the welding wire is controlled to be ≤0.02%, for example, it can be 0.001%, 0.005%, 0.01%, 0.012%, 0.015%, 0.018% or 0.02%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 0.01%-0.02%.

[0027] Boron is a grain boundary strengthening element that can improve the creep resistance of the heat-affected zone of the weld and increase the high-temperature strength of the weld. However, excessive boron content will form grain boundary borides with the cobalt matrix, causing brittle cracking of the weld.

[0028] In the present invention, the B content in the welding wire is controlled to be ≤0.02%, for example, it can be 0.001%, 0.005%, 0.01%, 0.012%, 0.015%, 0.018% or 0.02%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 0.01%-0.02%.

[0029] S and P elements are impurity elements in welding wire, which can easily cause grain boundary segregation, resulting in low-temperature embrittlement of the alloy, easily inducing welding hot cracks, and leading to failure of the weld joint.

[0030] In the present invention, the S content in the welding wire is controlled to be ≤0.01%, for example, it can be 0.001%, 0.003%, 0.005%, 0.008% or 0.01%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable. More preferably, S is ≤0.005%.

[0031] In the present invention, the P content in the welding wire is controlled to be ≤0.01%, for example, it can be 0.001%, 0.003%, 0.005%, 0.008% or 0.01%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable. More preferably, P is ≤0.005%.

[0032] Preferably, the hardness of the high-hardness cobalt-based alloy welding wire is 55-62HRC, for example, it can be 55HRC, 56HRC, 57HRC, 58HRC, 59HRC, 60HRC, 61HRC or 62HRC, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] In a second aspect, the present invention provides a method for preparing the high-hardness cobalt-based alloy welding wire according to the first aspect, the preparation method comprising the following steps:

[0034] (1) preparing raw materials according to the composition of the high-hardness cobalt-based alloy welding wire, and then sequentially performing vacuum induction melting, electroslag remelting, and homogenization heat treatment to obtain an alloy ingot;

[0035] (2) subjecting the alloy ingot to vacuum induction atomization pulverization to obtain alloy powder;

[0036] (3) The alloy powder is hot isostatically pressed to obtain the high-hardness cobalt-based alloy welding wire.

[0037] The preparation method of the present invention uses a dual melting process of vacuum induction melting and electroslag remelting to control the impurity content in the welding wire. Combined with a homogenizing heat treatment, this process improves component segregation and enhances compositional uniformity. For extremely high-hardness cobalt-based welding wire, a combination of vacuum induction gas atomization and hot isostatic pressing (HIP) is employed to reshape the cobalt-based welding wire and achieve densification and homogenization of its composition. This overcomes the difficulties associated with machining high-hardness welding wire, resulting in an extremely fine wire and improving its weldability.

[0038] Preferably, the melting temperature of the vacuum induction melting in step (1) is 1500-1540°C, for example, it can be 1500°C, 1505°C, 1510°C, 1515°C, 1520°C, 1525°C, 1530°C, 1535°C or 1540°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] Preferably, the casting temperature of the vacuum induction melting in step (1) is 1420-1460°C, for example, it can be 1420°C, 1425°C, 1430°C, 1435°C, 1440°C, 1445°C, 1450°C, 1455°C or 1460°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] Preferably, the voltage of the electroslag remelting in step (1) is 40-50V, for example, it can be 40V, 42V, 44V, 45V, 46V, 48V or 50V, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] Preferably, the current of the electroslag remelting in step (1) is 3800-4200A, for example, it can be 3800A, 3850A, 3900A, 3950A, 4000A, 4050A, 4100A, 4150A or 4200A, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] Preferably, the droplet frequency of the electroslag remelting in step (1) is 5.5-6.5 Hz, for example, it can be 5.5 Hz, 5.8 Hz, 6 Hz, 6.2 Hz or 6.5 Hz, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] Preferably, the slag heating temperature of the electroslag remelting in step (1) is 1540-1580°C, for example, it can be 1540°C, 1550°C, 1560°C, 1570°C or 1580°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] Preferably, the slag material for electroslag remelting in step (1) is CaF2-Al2O3-MgO-La2O3.

[0045] Preferably, the composition of the slag material includes, by mass percentage, CaF2 70%-80%, Al2O3 10%-15%, MgO 5%-12%, and La2O3 4%-7%.

[0046] The CaF2 content in the slag is 70%-80%, for example, it can be 70%, 72%, 75%, 78% or 80%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0047] The Al2O3 content in the slag is 10%-15%, for example, it can be 10%, 11%, 12%, 13%, 14% or 15%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0048] The MgO content in the slag is 5%-12%, for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11% or 12%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0049] The content of La2O3 in the slag is 4%-7%, for example, 4%, 5%, 6% or 7%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0050] Preferably, the temperature of the homogenization heat treatment in step (1) is 1250-1350°C, for example, it can be 1250°C, 1260°C, 1280°C, 1300°C, 1320°C, 1340°C or 1350°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0051] Preferably, the homogenization heat treatment time in step (1) is 90-110 h, for example, 90 h, 95 h, 100 h, 105 h or 110 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0052] Preferably, the particle size range of the alloy powder in step (2) is 26-53 μm, for example, it can be 26 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or 53 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] Preferably, the temperature of the hot isostatic pressing in step (3) is 1100-1200°C, for example, it can be 1100°C, 1120°C, 1140°C, 1150°C, 1160°C, 1180°C or 1200°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0054] Preferably, the pressure of the hot isostatic pressing in step (3) is 110-130 MPa, for example, it can be 110 MPa, 112 MPa, 115 MPa, 118 MPa, 120 MPa, 122 MPa, 125 MPa, 128 MPa or 130 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0055] Preferably, the diameter of the high-hardness cobalt-based alloy welding wire is ≤1.2 mm, for example, it can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm or 1.2 mm, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable. It is further preferred that the diameter is ≤1 mm.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The cobalt-based welding wire of the present invention significantly improves the hardness of the cobalt-based welding wire through the regulation of alloy elements, improves the uniformity of the welding wire composition, improves the welding strength, and has an extremely fine size, thereby improving the welding processability of the welding wire. DETAILED DESCRIPTION

[0058] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0059] Example 1

[0060] This embodiment provides a high-hardness cobalt-based alloy welding wire. The composition of the high-hardness cobalt-based alloy welding wire, measured by mass percentage, includes:

[0061] C 0.4%, Si 3.8%, Cr 17.1%, Ni 2.5%, Mo 28.9%, Fe 0.3%, La 0.01%, B 0.01%, S 0.005%, P 0.005%, Co 46.8%, and the balance are unavoidable impurities.

[0062] The preparation method of the high-hardness cobalt-based alloy welding wire comprises the following steps:

[0063] (1) According to the target composition of the cobalt-based alloy welding wire, metallic chromium, metallic nickel, metallic molybdenum, metallic iron, metallic cobalt, metallic lanthanum, graphite, boron and crystalline silicon are mixed to obtain a smelting raw material, and the smelting raw material is added to an induction melting furnace for vacuum induction melting at a vacuum degree of 0.1 Pa and a melting temperature of 1520° C. After being taken out of the furnace, casting is performed at a casting temperature of 1440° C. to obtain an ingot;

[0064] (2) electroslag remelting the obtained ingot, with the voltage controlled at 45 V and the current controlled at 4000 A, using CaF2-Al2O3-MgO-La2O3 as the slag material, and the specific composition of the slag material being: CaF2 75%, Al2O3 12%, MgO 8%, La2O3 5%, the slag heating temperature being 1560° C., and the droplet frequency being 6 Hz. After the electroslag remelting is completed, an electroslag ingot is obtained, and the electroslag ingot is sampled for component analysis to obtain the composition of the high-hardness cobalt-based alloy welding wire;

[0065] (3) The obtained electroslag ingot was homogenized and heat treated at 1300℃ under vacuum conditions with a vacuum degree of 3×10 -5 mbar, the homogenization heat treatment time is 100 h, and the alloy ingot is obtained;

[0066] (4) pulverizing the obtained alloy ingot by vacuum induction atomization to obtain alloy powder with a particle size ranging from 26 to 53 μm;

[0067] (5) hot isostatic pressing the obtained alloy powder at a temperature of 1150° C. and a pressure of 120 MPa to obtain a strip welding material with a size of 1.2×1.2×600 mm;

[0068] (6) The obtained strip welding material is subjected to external cylindrical machining to obtain the high hardness cobalt-based alloy welding wire, the size of which is

[0069] Example 2

[0070] This embodiment provides a high-hardness cobalt-based alloy welding wire. The composition of the high-hardness cobalt-based alloy welding wire, measured by mass percentage, includes:

[0071] C 0.3%, Si 4.0%, Cr 16.2%, Ni 3.0%, Mo 30.0%, Fe 0.1%, La 0.01%, B 0.02%, S 0.005%, P 0.005%, Co 46.2%, and the balance being unavoidable impurities.

[0072] The preparation method of the high-hardness cobalt-based alloy welding wire is the same as that in Example 1.

[0073] Example 3

[0074] This embodiment provides a high-hardness cobalt-based alloy welding wire. The composition of the high-hardness cobalt-based alloy welding wire, measured by mass percentage, includes:

[0075] C 0.5%, Si 3.6%, Cr 18.0%, Ni 2.1%, Mo 28.2%, Fe 0.9%, La 0.02%, B 0.02%, S 0.005%, P 0.005%, Co 46.5%, and the balance are unavoidable impurities.

[0076] The preparation method of the high-hardness cobalt-based alloy welding wire is the same as that in Example 1.

[0077] Example 4

[0078] This embodiment provides a high-hardness cobalt-based alloy welding wire. The composition of the high-hardness cobalt-based alloy welding wire, measured by mass percentage, includes:

[0079] C 0.3%, Si 3.1%, Cr 19.5%, Ni 1.5%, Mo 28.2%, Fe 0.5%, La 0.02%, B 0.02%, S 0.008%, P 0.009%, Co 46.7%, and the balance are unavoidable impurities.

[0080] The preparation method of the high hardness cobalt-based alloy welding wire is as follows:

[0081] (1) According to the target composition of the cobalt-based alloy welding wire, metallic chromium, metallic nickel, metallic molybdenum, metallic iron, metallic cobalt, metallic lanthanum, graphite, boron and crystalline silicon are mixed to obtain a smelting raw material, and the smelting raw material is added into an induction melting furnace for vacuum induction melting at a vacuum degree of 0.1 Pa and a melting temperature of 1500° C. After being taken out of the furnace, the raw material is cast at a casting temperature of 1420° C. to obtain an ingot;

[0082] (2) electroslag remelting the obtained ingot, with the voltage controlled at 40 V and the current controlled at 4200 A, using CaF2-Al2O3-MgO-La2O3 as the slag material, and the specific composition of the slag material being: CaF2 75%, Al2O3 12%, MgO 8%, La2O3 5%, the slag heating temperature being 1540° C., and the droplet frequency being 6.5 Hz. After the electroslag remelting is completed, an electroslag ingot is obtained, and the electroslag ingot is sampled for component analysis to obtain the composition of the high-hardness cobalt-based alloy welding wire;

[0083] (3) The obtained electroslag ingot was homogenized and heat treated at 1250℃ under vacuum conditions with a vacuum degree of 3×10 -5 mbar, and the homogenization heat treatment time was 110 h to obtain an alloy ingot;

[0084] (4) pulverizing the obtained alloy ingot by vacuum induction atomization to obtain alloy powder with a particle size ranging from 26 to 53 μm;

[0085] (5) hot isostatic pressing the obtained alloy powder at a temperature of 1100° C. and a pressure of 130 MPa to obtain a strip welding material with a size of 1.2×1.2×600 mm;

[0086] (6) The obtained strip welding material is subjected to external cylindrical machining to obtain the high hardness cobalt-based alloy welding wire, the size of which is

[0087] Example 5

[0088] This embodiment provides a high-hardness cobalt-based alloy welding wire. The composition of the high-hardness cobalt-based alloy welding wire, measured by mass percentage, includes:

[0089] C 0.2%, Si 3.8%, Cr 15.1%, Ni 3.9%, Mo 25.5%, Fe 0.5%, La 0.02%, B 0.02%, S 0.010%, P 0.010%, Co 50.8%, and the balance is unavoidable impurities.

[0090] The preparation method of the high hardness cobalt-based alloy welding wire is as follows:

[0091] (1) According to the target composition of the cobalt-based alloy welding wire, metallic chromium, metallic nickel, metallic molybdenum, metallic iron, metallic cobalt, metallic lanthanum, graphite, boron and crystalline silicon are mixed to obtain a smelting raw material, and the smelting raw material is added to an induction melting furnace for vacuum induction melting at a vacuum degree of 0.1 Pa and a melting temperature of 1540° C. After being taken out of the furnace, casting is performed at a casting temperature of 1460° C. to obtain an ingot;

[0092] (2) electroslag remelting the obtained ingot, with the voltage controlled at 50 V and the current controlled at 3800 A, using CaF2-Al2O3-MgO-La2O3 as the slag material, and the specific composition of the slag material being: CaF2 75%, Al2O3 12%, MgO 8%, La2O3 5%, the slag heating temperature being 1580° C., and the droplet frequency being 5.5 Hz. After the electroslag remelting is completed, an electroslag ingot is obtained, and the electroslag ingot is sampled for component analysis to obtain the composition of the high-hardness cobalt-based alloy welding wire;

[0093] (3) The obtained electroslag ingot was homogenized and heat treated at 1350℃ under vacuum conditions with a vacuum degree of 3×10 - 5 mbar, and the homogenization heat treatment time was 90 h to obtain an alloy ingot;

[0094] (4) pulverizing the obtained alloy ingot by vacuum induction atomization to obtain alloy powder with a particle size ranging from 26 to 53 μm;

[0095] (5) hot isostatic pressing the obtained alloy powder at a temperature of 1200° C. and a pressure of 110 MPa to obtain a strip welding material with a size of 1.2×1.2×600 mm;

[0096] (6) The obtained strip welding material is subjected to external cylindrical machining to obtain the high hardness cobalt-based alloy welding wire, the size of which is

[0097] Performance Testing

[0098] The cobalt-based alloy welding wires provided in the examples and comparative examples were subjected to performance tests, and the results are shown in Table 1.

[0099] Hardness test: Take 3 points for each welding wire to perform hardness test and calculate the average value to obtain the hardness of the cobalt-based alloy welding wire.

[0100] Table 1

[0101] Serial number Hardness (HRC) Example 1 61.5 Example 2 60.8 Example 3 60.2 Example 4 58.9 Example 5 57.0

[0102] In summary, the cobalt-based welding wire of the present invention significantly improves the hardness of the cobalt-based welding wire by regulating the alloy elements. The hardness of the welding wire is 57.0-61.5HRC, and the uniformity of the welding wire composition is improved, the welding strength is improved, the welding wire size is extremely fine, and the welding processability of the welding wire is improved.

[0103] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A high hardness cobalt-based alloy welding wire, characterized in that: The composition of the high hardness cobalt-based alloy welding wire includes, by mass percentage: C≤0.5%, Si 3%-4%, Cr 15%-20%, Ni 1%-4%, Mo 25%-30%, Co 45%-55%, Fe≤1%, La≤0.02%, B≤0.02%, S≤0.01%, P≤0.01%.

2. The high hardness cobalt-based alloy welding wire according to claim 1, characterized in that: The composition of the high hardness cobalt-based alloy welding wire includes, by mass percentage: C 0.3%-0.5%, Si 3.6%-4%, Cr 16%-18%, Ni 2%-3%, Mo 28%-30%, Co 45%-50%, Fe 0.1%-1%, La 0.01%-0.02%, B 0.01%-0.02%, S≤0.005%, P≤0.005%.

3. The high hardness cobalt-based alloy welding wire according to claim 1 or 2, characterized in that: The hardness of the high-hardness cobalt-based alloy welding wire is 55-62HRC.

4. A method for preparing a high-hardness cobalt-based alloy welding wire according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) preparing raw materials according to the composition of the high-hardness cobalt-based alloy welding wire, and then sequentially performing vacuum induction melting, electroslag remelting, and homogenization heat treatment to obtain an alloy ingot; (2) subjecting the alloy ingot to vacuum induction atomization pulverization to obtain alloy powder; (3) The alloy powder is hot isostatically pressed to obtain the high-hardness cobalt-based alloy welding wire.

5. The preparation method according to claim 4, characterized in that The melting temperature of the vacuum induction melting in step (1) is 1500-1540° C. Preferably, the casting temperature of the vacuum induction melting in step (1) is 1420-1460°C.

6. The preparation method according to claim 4 or 5, characterized in that The voltage of the electroslag remelting in step (1) is 40-50V; Preferably, the current of the electroslag remelting in step (1) is 3800-4200A; Preferably, the droplet frequency of the electroslag remelting in step (1) is 5.5-6.5 Hz; Preferably, the slag heating temperature of the electroslag remelting in step (1) is 1540-1580°C.

7. The preparation method according to any one of claims 4 to 6, characterized in that The slag material for electroslag remelting in step (1) is CaF2-Al2O3-MgO-La2O3; Preferably, the composition of the slag material includes, by mass percentage, CaF2 70%-80%, Al2O3 10%-15%, MgO 5%-12%, and La2O3 4%-7%.

8. The preparation method according to any one of claims 4 to 7, characterized in that The temperature of the homogenization heat treatment in step (1) is 1250-1350°C; Preferably, the homogenization heat treatment time in step (1) is 90-110 hours.

9. The preparation method according to any one of claims 4 to 8, characterized in that The particle size range of the alloy powder in step (2) is 26-53 μm.

10. The preparation method according to any one of claims 4 to 9, characterized in that: The temperature of the hot isostatic pressing in step (3) is 1100-1200° C. Preferably, the pressure of the hot isostatic pressing in step (3) is 110-130 MPa; Preferably, the diameter of the high-hardness cobalt-based alloy welding wire is ≤1.2 mm.