Nickel-based alloy powder, preparation method and application of nickel-based alloy powder and repairing method of cold-end rotor blade of gas turbine

Abstract

The invention belongs to the technical field of gas turbines, and particularly relates to nickel-based alloy powder, a preparation method and application thereof and a repairing method of a cold-end rotor blade of a gas turbine. The nickel-based alloy powder provided by the invention comprises the following element components in percentage by mass: 15 to 17 percent of Cr, 23 to 25 percent of Co, 3 to 6 percent of Mo, 3.5 to 5.5 percent of W, 2.3 to 2.5 percent of Al, 2.5 to 3.0 percent of Ti, 2 to 4 percent of Ta, 1.9 to 2.5 percent of Nb, 0.06 to 0.1 percent of C, 0.004 to 0.008 percent of B, 0.5 to 1.0 percent of Zr, 3 to 5 percent of Re and the balance of Ni and inevitable impurities. After the nickel-based alloy powder provided by the invention is used for repairing the cold-end rotor blade of the gas turbine, the nickel-based alloy powder has relatively high strength, wear resistance and high temperature resistance; and the repaired area has no crack.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine technology, specifically relating to a nickel-based alloy powder, its preparation method and application, and a method for repairing cold-end rotor blades of a gas turbine. Background Technology

[0002] Heavy-duty gas turbines primarily use axial-flow compressors to compress air. In the compressor rotor blade tip region, due to the significant pressure difference between the pressure and suction sides, leakage and overflow occur from the pressure side to the suction side. This leads to wear on the cold-end rotor blades of the gas turbine during long-term service. Traditional methods for repairing wear mainly fall into two categories: one is repair using a sprayed wear-resistant layer, but this method has low bonding strength and is prone to chipping under extreme service conditions. The second method is repair using traditional laser welding with the same material as the blade. While this restores the blade profile, the wear resistance and strength are lower than those of the blade substrate. Summary of the Invention

[0003] In view of this, the present invention provides a nickel-based alloy powder, its preparation method and application, and a method for repairing cold-end rotor blades of gas turbines. The cold-end rotor blades of gas turbines repaired using the nickel-based alloy powder provided by the present invention have good mechanical strength and wear resistance.

[0004] To address the aforementioned technical problems, this invention provides a nickel-based alloy powder comprising the following elemental components by mass percentage: Cr 15~17%; Co 23~25%; Mo 3~6%; W 3.5~5.5%; Al 2.3~2.5%; Ti 2.5~3.0%; Ta 2~4%; Nb 1.9~2.5%; C 0.06~0.1%; B 0.004~0.008%; Zr 0.5~1.0%; Re 3~5%; Ni and unavoidable impurity margins.

[0005] Preferably, the particle size of the nickel-based alloy powder is 20~63μm.

[0006] This invention also provides a method for preparing the nickel-based alloy powder described in the above technical solution, comprising the following steps: Chromium, cobalt, molybdenum, tungsten, aluminum, titanium, tantalum, niobium, carbon, boron, zirconium, rhenium, and nickel are mixed in a certain elemental ratio and smelted to obtain a molten liquid. The molten liquid is atomized to produce the nickel-based alloy powder.

[0007] Preferably, the melting temperature is 1500~1550℃, and the vacuum degree of the melting is 1×10⁻⁶. -4 ~9×10 - 4 Pa, the melting time is 60~80min.

[0008] Preferably, the conditions for atomization powder production include: atomizing gas pressure of 5~8MPa and atomizing nozzle diameter of 1~1.5mm.

[0009] Preferably, the process after atomization further includes: sieving the atomized powder product to obtain the alloy powder; the particle size of the alloy powder is 20~63μm.

[0010] The present invention also provides the application of the nickel-based alloy powder described in the above technical solution or the nickel-based alloy powder prepared by the preparation method described in the above technical solution in the preparation and repair of cold-end rotor blades of gas turbines.

[0011] This invention also provides a method for repairing cold-end rotor blades of a gas turbine using nickel-based alloy powder, comprising the following steps: The repaired gas turbine cold-end rotor blades are obtained by pulsed laser welding of the parts to be repaired using nickel-based alloy powder as raw material, followed by mechanical grinding and annealing. The nickel-based alloy powder is the nickel-based alloy powder described in the above technical solution or the nickel-based alloy powder prepared by the preparation method described in the above technical solution.

[0012] Preferably, the material of the cold-end rotor blades of the gas turbine is a nickel-based alloy; The process before pulsed laser welding also includes: cutting the worn area and inserting the cut component into a fixture; The conditions for pulsed laser welding include: laser spot size 1~1.5mm, pulse frequency 5~8kHz, laser power 800~1000W, and powder feed rate 4~5g / min.

[0013] Preferably, the annealing treatment is performed at a temperature of 750~770℃ for a time of 0.8~1.2h.

[0014] This invention provides a nickel-based alloy powder comprising the following elemental components by mass percentage: 15-17% Cr, 23-25% Co, 3-6% Mo, 3.5-5.5% W, 2.3-2.5% Al, 2.5-3.0% Ti, 2-4% Ta, 1.9-2.5% Nb, 0.06-0.1% C, 0.004-0.008% B, 0.5-1.0% Zr, 3-5% Re, with the balance being Ni and unavoidable impurities. In this invention, Re improves the high-temperature mechanical properties of the alloy, while specific amounts of Al and Ti improve the alloy's oxidation resistance, thereby enhancing its wear resistance. The combined effect of these elements gives the nickel-based alloy powder excellent mechanical strength, wear resistance, and high-temperature resistance. The nickel-based alloy powder provided by this invention is used to repair the cold-end rotor blades of gas turbines, resulting in high strength, wear resistance, and high-temperature resistance. Its mechanical strength is 1700 MPa, and there are no cracks in the repaired area. The wear is significantly reduced, and the temperature resistance is 250°C higher than that of the base material. Its service life is twice that of the base blades. Attached Figure Description

[0015] Figure 1 A schematic diagram of the structure for inserting the cut component into the fixture before pulsed laser welding. Detailed Implementation

[0016] This invention provides a nickel-based alloy powder comprising the following elemental components in weight percentage: Cr 15~17%; Co 23~25%; Mo 3~6%; W 3.5~5.5%; Al 2.3~2.5%; Ti 2.5~3.0%; Ta 2~4%; Nb 1.9~2.5%; C 0.06~0.1%; B 0.004~0.008%; Zr 0.5~1.0%; Re 3~5%; Ni and unavoidable impurity margins.

[0017] The nickel-based alloy powder provided by the present invention comprises 15-17% Cr by weight percentage, which can be 15.5%, 16% or 16.5%.

[0018] The nickel-based alloy powder provided by the present invention comprises 23-25% Co by weight percentage, which can be 23.5%, 24% or 24.5%.

[0019] The nickel-based alloy powder provided by the present invention comprises 3 to 6% Mo by weight, which can be 3.5%, 4%, 4.5%, 5% or 5.5%.

[0020] The nickel-based alloy powder provided by the present invention comprises 3.5 to 5.5% W by weight, which can be 4%, 4.5% or 5%.

[0021] The nickel-based alloy powder provided by the present invention comprises 2.3 to 2.5% Al by weight, which can be 2.4%.

[0022] The nickel-based alloy powder provided by the present invention comprises 2.5 to 3.0% Ti by mass percentage, which can be 2.6%, 2.7%, 2.8% or 2.9%.

[0023] The nickel-based alloy powder provided by the present invention comprises 2-4% Ta by weight percentage, which can be 2.5%, 3% or 3.5%.

[0024] The nickel-based alloy powder provided by the present invention comprises 1.9 to 2.5% Nb by weight percentage, which can be 2%, 2.1%, 2.2%, 2.3% or 2.4%.

[0025] The nickel-based alloy powder provided by this invention comprises 0.06~0.1% C by weight, which can be 0.07%, 0.08%, or 0.09%. The nickel-based alloy powder provided by this invention comprises 0.004~0.008% B by mass percentage, which can be 0.005%, 0.006% or 0.007%. In this invention, B is an intergranular strengthening element.

[0026] The nickel-based alloy powder provided by the present invention comprises 0.5 to 1.0% Zr by weight percentage, which can be 0.6%, 0.7%, 0.8% or 0.9%.

[0027] The nickel-based alloy powder provided by the present invention comprises 3 to 5% Re by weight percentage, which can be 3.5%, 4% or 4.5%.

[0028] The nickel-based alloy powder provided by this invention, by mass percentage, includes the balance Ni and unavoidable impurities. In this invention, the unavoidable impurities include O and N; the mass percentage of O can be 0.012~0.02%, specifically 0.014%, 0.016%, or 0.018%; the mass percentage of N can be 0.01~0.02%, specifically 0.013%, 0.016%, or 0.018%.

[0029] In this invention, Cr improves the corrosion resistance of the alloy, Co, Mo, and W improve the high-temperature stability of the alloy, and Al and Ti improve the oxidation resistance of the alloy.

[0030] In one specific embodiment of the present invention, the particle size of the nickel-based alloy powder can be 20~63μm, 30~60μm, or even 35~50μm.

[0031] This invention also provides a method for preparing the nickel-based alloy powder described in the above technical solution, comprising the following steps: Chromium, cobalt, molybdenum, tungsten, aluminum, titanium, tantalum, niobium, carbon, boron, zirconium, rhenium, and nickel are mixed in a certain elemental ratio and smelted to obtain a molten liquid. The molten liquid is atomized to produce the nickel-based alloy powder.

[0032] In this invention, unless otherwise specified, all materials are conventional commercially available products.

[0033] This invention involves mixing and smelting chromium, cobalt, molybdenum, tungsten, aluminum, titanium, tantalum, niobium, carbon, boron, zirconium, rhenium, and nickel in a specific elemental ratio to obtain a molten liquid. This invention does not have any special requirements regarding the source of the chromium, cobalt, molybdenum, tungsten, aluminum, titanium, tantalum, niobium, carbon, boron, zirconium, rhenium, and nickel; conventional materials in the art can be used.

[0034] In one specific embodiment of the present invention, the melting temperature can be 1500~1550℃, specifically 1510℃, 1520℃, 1530℃ or 1540℃; the vacuum degree of the melting can be 1×10 -4 ~9×10 -4 Pa, the melting time can be 60~80min, specifically 65min, 70min or 75min.

[0035] After obtaining the molten liquid, the present invention atomizes the molten liquid to obtain the nickel-based alloy powder. As a specific embodiment of the present invention, the atomization conditions may include: an atomizing gas pressure of 5-8 MPa and an atomizing nozzle diameter of 1-1.5 mm; the atomizing gas pressure may specifically be 5.5 MPa, 6 MPa, 6.5 MPa, 7 MPa, or 7.5 MPa.

[0036] In one specific embodiment of the present invention, the atomization powdering process may further include: sieving the atomized powder product to obtain the alloy powder; the particle size of the alloy powder may be 20~63μm. The present invention does not have a special limitation on the aperture of the sieve used for sieving, as long as it can obtain alloy powder within the required particle size range.

[0037] The present invention also provides the application of the nickel-based alloy powder described in the above technical solution or the nickel-based alloy powder prepared by the preparation method described in the above technical solution in the preparation and repair of cold-end rotor blades of gas turbines.

[0038] This invention also provides a method for repairing cold-end rotor blades of a gas turbine using nickel-based alloy powder, comprising the following steps: The part to be repaired is subjected to pulsed laser welding using nickel-based alloy powder as raw material, followed by mechanical grinding and annealing to obtain the repaired cold-end rotor blade of the gas turbine; the nickel-based alloy powder is the nickel-based alloy powder described in the above technical solution or the nickel-based alloy powder prepared by the preparation method described in the above technical solution.

[0039] In one specific embodiment of the present invention, the material of the cold-end rotor blade of the gas turbine can be a nickel-based alloy; the nickel-based alloy can be GH4169.

[0040] As a specific embodiment of the present invention, the process may further include: cutting the worn part before pulsed laser welding, and inserting the cut component into a fixture; the fixture is in close contact with the blade. Figure 1 This is a schematic diagram of the structure for inserting the cut component into the fixture. In this invention, the fixture's function is to ensure that the near-air edge and exhaust edge of the blade do not bite together during the repair process, thus avoiding any impact on the overall shape and structure of the blade from welding.

[0041] As a specific embodiment of the present invention, the conditions for pulsed laser welding may include: laser spot size of 1~1.5mm, pulse frequency of 5~8kHz, laser power of 800~1000W, and powder feed rate of 4~5g / min; the laser spot size may specifically be 1.1mm, 1.2mm, 1.3mm or 1.4mm; the pulse frequency may specifically be 5kHz, 6kHz or 7kHz; the laser power may specifically be 850W, 900W or 950W; and the powder feed rate may specifically be 4.3g / min, 4.5g / min or 4.8g / min.

[0042] The present invention does not have special requirements for the mechanical polishing; conventional methods in the field can be used.

[0043] In one specific embodiment of the present invention, the annealing temperature can be 750~770℃, specifically 755℃, 760℃, or 765℃; the annealing time can be 0.8~1.2h, specifically 1h. The annealing treatment of the present invention can remove stress and improve mechanical properties.

[0044] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1 Chromium, cobalt, molybdenum, tungsten, aluminum, titanium, tantalum, niobium, carbon, boron, zirconium, rhenium, and nickel are mixed in a specific elemental ratio at a temperature of 1550℃ and a vacuum level of 1×10⁻⁶. -4 Melt for 70 minutes under Pa conditions to obtain a molten liquid; The molten metal was atomized and then sieved to obtain nickel-based alloy powder with a particle size of 20-63 μm. The atomization conditions were: atomizing gas pressure of 7 MPa and atomizing nozzle diameter of 1 mm. The obtained nickel-based alloy powder, by mass percentage, consisted of 17% Cr, 24% Co, 5% Mo, 4% W, 2.4% Al, 2.6% Ti, 3% Ta, 2.2% Nb, 0.08% C, 0.006% B, 0.7% Zr, 4% Re, 0.012% O, 0.01% N, and the balance Ni.

[0046] Example 2 Using a gas turbine cold-end rotor blade (substrate) made of GH4169 material as the object to be repaired, the worn part is cut, and the cut component is inserted into the fixture to make the component and the fixture fit tightly together. Using the nickel-based alloy powder prepared in Example 1 as raw material, the part to be repaired was subjected to pulsed laser welding, followed by mechanical grinding and annealing to obtain the repaired cold-end rotor blade of the gas turbine. The pulsed laser welding conditions included: laser spot size of 1 mm, pulse frequency of 5 kHz, laser power of 900 W, and powder feed rate of 4.5 g / min; the annealing temperature was 760 °C, and the annealing time was 1 h.

[0047] The room temperature tensile strength of the repaired area and the substrate formed in Example 2 was tested according to GB / T 228.1-2010, and the results are listed in Table 1. The high-temperature (650℃, 900℃) durability of the repaired area formed in Example 2 was tested according to GB / T 2039-2012. The wear resistance of the substrate and the repaired area was tested according to the national standard GB / T 12444 "Metallic Materials - Test Methods for Wear," and the wear results are listed in Table 1. The test conditions included: friction force of 50 MPa, friction speed of 500 m / s, and friction time of 10 min.

[0048] Table 1 Performance results of the matrix and repaired area in Example 2

[0049] As can be seen from Table 1, the repaired area formed by using the nickel-based alloy powder prepared in Example 1 as raw material has high tensile strength and high-temperature durability; the wear of the substrate is 2.5 times that of the repaired area, indicating that the repaired area has good wear resistance.

[0050] According to GB / T 228.1-2010, the bonding strength between the repaired area and the substrate of the gas turbine cold-end rotor blade in Example 2 was tested, and the result was 1100 MPa, indicating that the nickel-based alloy powder provided by the present invention has good bonding performance for repairing the gas turbine cold-end rotor blade.

[0051] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A nickel-based alloy powder, characterized in that, The nickel-based alloy powder comprises the following element components in percentage by mass: Cr 15~17%； Co 23~25%; Mo 3~6%; W 3.5~5.5%； Al 2.3~2.5%； Ti 2.5~3.0%; Ta 2~4%; Nb 1.9~2.5%; C 0.06~0.1%； B 0.004~0.008%； Zr 0.5~1.0%； Re 3~5%; Ni and inevitable impurities, balance.

2. The nickel-based alloy powder of claim 1, wherein, The particle size of the nickel-based alloy powder is 20~63μm.

3. The method of producing a nickel-based alloy powder according to claim 1 or 2, characterized in that, The method comprises the following steps: melting the chromium element, the cobalt element, the molybdenum element, the tungsten element, the aluminum element, the titanium element, the tantalum element, the niobium element, the carbon element, the boron element, the zirconium element, the rhenium element and the nickel element according to the element ratio to obtain a molten liquid; atomizing the molten liquid to obtain the nickel-based alloy powder.

4. The preparation method according to claim 3, characterized in that, The temperature of the smelting is 1500-1550℃, the vacuum degree of the smelting is 1x10 -4 ~9x10 -4 Pa, and the time of the smelting is 60-80min.

5. The preparation method according to claim 3, characterized in that, The atomizing condition comprises: the atomizing gas pressure is 5~8MPa, and the atomizing nozzle diameter is 1~1.5mm.

6. The preparation method according to claim 3 or 5, characterized in that, After the atomizing, the method further comprises: screening the atomized product to obtain the alloy powder; and the particle size of the alloy powder is 20~63μm.

7. The nickel-based alloy powder of claim 1 or 2 or the nickel-based alloy powder prepared by the method of any one of claims 3~6 is applied to the preparation or repair of a gas turbine cold end rotor blade.

8. A method for repairing a cold end rotor blade of a gas turbine with a nickel-based alloy powder, characterized in that The method comprises the following steps: pulsed laser welding the worn part by using the nickel-based alloy powder as raw material, and then sequentially performing mechanical polishing and annealing treatment to obtain a repaired gas turbine cold end rotor blade; the nickel-based alloy powder is the nickel-based alloy powder of claim 1 or 2 or the nickel-based alloy powder prepared by the method of any one of claims 3~6.

9. The method of claim 8, wherein, The material of the gas turbine cold end rotor blade is a nickel-based alloy. Before the pulsed laser welding, the method further comprises: cutting the worn part, and inserting the cut part into a clamp. The pulsed laser welding condition comprises: the laser spot is 1~1.5mm, the pulse frequency is 5~8kHz, the laser power is 800~1000W, and the powder feeding amount is 4~5g / min.

10. The method of claim 8, wherein, The annealing temperature is 750~770℃, and the annealing time is 0.8~1.2h.

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