Nickel-based superalloy for brush type sealing and preparation method and application of nickel-based superalloy

Abstract

The embodiment of the invention discloses a nickel-based superalloy for brush sealing and a preparation method and application thereof. The nickel-based high-temperature alloy is prepared from the following components in percentage by weight: 0.03 to 0.10 percent of C, 0.01 to 0.08 percent of Mn, 19.00 to 21.00 percent of Cr, 3.20 to 3.70 percent of Al, 2.00 to 4.00 percent of Fe, 1.00 to 3.60 percent of Mo, 0.01 to 0.50 percent of Co, 0.001 to 0.05 percent of La and the balance of nickel and inevitable impurities. When the alloy is stretched at the room temperature, the tensile strength reaches 1200 MPa or above, the yield strength is within the required range, the average oxidation rate is reduced to 0.0006 g / m < 2 >. H or below, and the alloy has good oxidation resistance, does not crack during forging machining, has good hot working performance and meets the design and use requirements of advanced aero-engines and gas turbines.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of metallurgy technology, and specifically to a nickel-based high-temperature alloy for brush seals and a preparation method and application thereof. Background Art

[0002] Brush seals are a type of high-efficiency damping seal, with a leakage rate of 1 / 5 to 1 / 10 of that of comb-tooth labyrinth seals. When the engine axis is not concentric during startup and shutdown, it can still maintain flexible contact to keep the sealing capacity unchanged. Brush seals can withstand rotor linear speeds exceeding 305m / s and operating temperatures above 700°C. They are one of the key technologies for the development of modern advanced turbine machinery. The most anticipated application area for brush seals in academia and engineering is aviation engines. They are also used in industrial gas turbines and steam turbines. Against the backdrop of national carbon peak and carbon neutrality, the development of advanced sealing technology is an urgent need for power and power generation equipment.

[0003] The engine operating conditions of aircraft engines and gas turbines are both high-temperature environments. In order to meet the performance and use requirements, the main materials used are high-temperature alloys. High-temperature alloys refer to alloys that can have good organizational stability under temperatures above 600°C, can work stably, and can withstand large stresses, and have good high-temperature properties such as corrosion resistance and oxidation resistance. Among them, nickel-based high-temperature alloys are most widely used in the aerospace field, with about 45% of the usage being nickel-based high-temperature alloys. The main components of nickel-based high-temperature alloys are Ni, Co, Cr, W, Mo, Re, Ru, Al, Ta, Ti and other elements. The matrix is ​​Ni, and the general content is above 55%. The main operating temperature range is 650-1100°C. When serving in this temperature range, it has higher strength, stronger oxidation resistance and corrosion resistance. Summary of the invention

[0004] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0005] Nickel-based superalloys are key materials for important parts such as turbine disks and hot end parts on aircraft engines. As the thrust level of aircraft engines and the flight speed of missiles continue to develop and increase, the nickel-based superalloys currently used are gradually unable to meet the requirements of higher and higher operating temperatures, and are prone to defects such as oxidation and cracking, which affect the service life and performance of aircraft engines. Therefore, it is necessary to study and develop a nickel-based superalloy that is resistant to oxidation, not prone to cracking, and has good comprehensive mechanical properties to meet the needs of aircraft engines, gas turbines, steam turbines and other equipment that need to be used at higher temperatures.

[0006] In order to achieve the above purpose, the embodiment of the present invention provides the following technical solutions:

[0007] According to a first aspect of an embodiment of the present invention, the present invention provides a nickel-based high-temperature alloy for brush seals, wherein the nickel-based high-temperature alloy includes, by weight percentage, C: 0.03-0.10%, Mn: 0.01-0.08%, Cr: 19.00-21.00%, Al: 3.20-3.70%, Fe: 2.00-4.00%, Mo: 1.00-3.60%, Co: 0.01-0.50%, La: 0.001-0.05%, and the balance is nickel and unavoidable impurities.

[0008] Advantages and technical effects of the nickel-based high-temperature alloy for brush seals according to the embodiment of the present invention:

[0009] 1. In the embodiment of the present invention, compared with the existing nickel-based high-temperature alloy, the amount of Cr element is increased, and a part of the Cr element is melted into the γ' phase to play a strengthening role, and a small amount of carbide is formed, which plays a carbide strengthening role. Most of the rest is dissolved in the γ matrix. The Cr element dissolved in the matrix will cause lattice distortion and generate an elastic stress field, which plays a solid solution strengthening role. At the same time, the Cr element also reduces the solid solution stacking dislocation energy and improves the high-temperature endurance strength of the alloy. In addition, the most important role of the Cr element in the high-temperature alloy is to form a Cr2O3 type oxide film to improve the oxidation resistance and corrosion resistance of the alloy. Therefore, in the embodiment of the present invention, the Cr content is controlled within the range of 19.00 to 21.00wt%;

[0010] 2. In the embodiment of the present invention, most of the Mo atoms are dissolved in the γ matrix, accounting for about 1 / 4 of the γ' phase. Mo significantly increases the lattice constant of the Ni solid solution and significantly improves the room temperature and high temperature yield strength. The addition of Mo will also form a large amount of M 23 C6 carbide can also play a strengthening role, but the Mo element will promote the formation of μ phase, which is not conducive to long-term organizational stability. Therefore, the control range of the Mo element is proposed in the embodiment of the present invention, and the content of the Mo element is controlled to 1.00-3.60wt%;

[0011] 3. In the embodiments of the present invention, through reasonable element composition design, the alloy has sufficient strength and suitable elastic modulus, and at the same time has excellent oxidation resistance, no cracks appear during forging, and has good hot working performance, which can meet the requirements of advanced aircraft engine and gas turbine design and use.

[0012] Furthermore, the weight percentages of Co, Mo, Al and La satisfy the relationship 1.10≤(7Co+1.3Mo) / (Al+11La)≤1.50.

[0013] Furthermore, the weight percentages of Co, Mo, Al and La satisfy the relationship 1.25≤(7Co+1.3Mo) / (Al+11La)≤1.45.

[0014] Furthermore, the weight percentage of Cr is 19.10-20.10%, the weight percentage of Mo is 1.80-3.05%, the weight percentage of Co is 0.10-0.25%, and the weight percentage of La is 0.001-0.015%.

[0015] According to a second aspect of an embodiment of the present invention, the present invention provides a method for preparing a nickel-based high-temperature alloy for brush seals as described in any one of the above items, the method comprising the following steps:

[0016] (1) Cr, Fe, Mo, Ni, and Co raw materials that are not easy to burn are placed in a vacuum induction furnace, heated to melt, cooled, and Al, Mn, C, and La raw materials that are easy to burn are added, and then the temperature is raised, stirred evenly, and then cooled again, and cast in a vacuum environment to obtain an electrode rod;

[0017] (2) subjecting the electrode rod to vacuum consumable remelting or atmosphere-protected electroslag remelting to obtain a remelted alloy ingot;

[0018] (3) forging and hot rolling the remelted alloy ingot to obtain a wire rod;

[0019] (4) subjecting the wire rod to a cold drawing-grinding-heat treatment process cycle, wherein the drawing reduction ratio between each heat treatment is controlled to be 30 to 55%, so that the diameter is gradually reduced to obtain a wire material of target diameter;

[0020] (5) heat treating the wire material with the target diameter to obtain the high-temperature alloy.

[0021] Furthermore, in step (1), the vacuum degree of the vacuum induction furnace is 0.1-0.5 Pa, the heating temperature is 1540-1600°C, the cooling temperature is 1400-1460°C, the heating temperature is 1540-1600°C, and the cooling temperature is 1420-1490°C; the size of the electrode rod is Φ140-Φ320 mm.

[0022] Furthermore, in step (2), the size of the remelted alloy ingot is Φ180 to Φ380 mm;

[0023] In step (3), the billet is heated to 1160-1200° C. before forging and hot rolling, and is kept warm for 60-90 minutes before forging and for 35-55 minutes before hot rolling; the size of the wire rod is Ф5-Ф9 mm.

[0024] Furthermore, in step (4), the temperature of the heat treatment is 1050-1080°C, the holding time is calculated dimensionlessly, and the holding time in seconds T of the heat treatment has the following relationship with the wire diameter Φ: when Φ≥0.5mm, 55≤T / Φ≤80; when Φ<0.5mm, 80<T / Φ≤190; the size of the target diameter wire is Φ0.05-Φ0.15mm.

[0025] Furthermore, in step (5), the heat treatment temperature is 800-1000° C., and the insulation time is 0.1-6 min.

[0026] According to a third aspect of an embodiment of the present invention, the present invention provides use of the nickel-based high-temperature alloy for brush seals as described in any one of the above items in an aircraft engine, a gas turbine or a steam turbine.

[0027] The embodiments of the present invention have the following advantages:

[0028] 1. The alloy provided by the present invention has excellent oxidation resistance, room temperature tensile properties and elastic modulus, meeting the requirements for the design and use of advanced aircraft engines and gas turbines;

[0029] 2. The alloy provided by the present invention has good straightness, which meets the requirements of brush seal ring for wire straightness design and use;

[0030] 3. The alloy preparation method provided by the present invention can reduce the risks of wire breakage due to excessive surface reduction rate, abnormal grain size growth due to too long heat treatment holding time, and breakage due to too long holding time when the wire is fine, thereby reducing the number of wire breakages, effectively improving production efficiency, and meeting the technical requirements of large axle weight. DETAILED DESCRIPTION

[0031] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] This embodiment provides a method for preparing a nickel-based high-temperature alloy for brush seals:

[0034] (1) Cr, Fe, Mo, Ni, and Co raw materials that are not easy to burn are placed in a vacuum induction furnace (vacuum degree is 0.1-0.5 Pa) and melted at a melting temperature of 1580°C. The temperature is then lowered to 1420°C, and Al, Mn, C, and La raw materials that are easy to burn are added. The temperature is raised to 1580°C, stirred evenly, and then kept warm and allowed to stand. After the temperature is lowered to 1450°C, electrode rods with a diameter of Φ140-Φ320 mm are directly cast in a vacuum environment.

[0035] (2) The electrode rod obtained in step (1) is subjected to vacuum consumable remelting or atmosphere shielded electroslag remelting to obtain a remelted alloy ingot of Φ180 to Φ380 mm.

[0036] (3) The remelted alloy ingot obtained in step (2) is forged and hot-rolled, the billet is heated to 1180° C. before forging and hot-rolling, and is kept warm for 60 minutes before forging and for 40 minutes before hot-rolling to obtain a wire rod with a diameter of 5 mm to 9 mm;

[0037] (4) subjecting the wire rod obtained in step (3) to a "cold drawing-grinding-heat treatment" process cycle, wherein the drawing reduction ratio between each heat treatment is 45%, the heat treatment temperature is 1060° C., the holding time is dimensionless, and the heat treatment holding time T (seconds) and the wire diameter Φ (mm) have the following relationship: when Φ ≥ 0.5 mm, 55 ≤ T / Φ ≤ 80; when Φ < 0.5 mm, 80 < T / Φ ≤ 190, and a target diameter wire of Φ 0.05 to Φ 0.15 mm is obtained;

[0038] (5) The target diameter wire obtained in step (4) is heat treated to obtain a finished product, the heat treatment temperature is 900° C., and the heat treatment time is 3 min.

[0039] The composition of the alloy prepared in Example 1 is shown in Table 1, and the properties are shown in Table 2.

[0040] Embodiment 2-4

[0041] The preparation methods of Examples 2-4 are the same as those of Example 1, except that the alloy compositions are different. The alloy compositions of Examples 2-4 are shown in Table 1, and the properties are shown in Table 2.

[0042] Comparative Example 1

[0043] The preparation method of Comparative Example 1 is the same as that of Example 1, except that (7Co+1.3Mo) / (Al+11La)=0.941. The alloy composition of Comparative Example 1 is shown in Table 1, and the properties are shown in Table 2.

[0044] Comparative Example 2

[0045] The preparation method of Comparative Example 2 is the same as that of Example 1, except that the content of element La in the alloy composition is 0.068%, (7Co+1.3Mo) / (Al+11La)=0.526. The alloy composition prepared in Comparative Example 2 is shown in Table 1, and the properties are shown in Table 2.

[0046] Comparative Example 3

[0047] The preparation method of Comparative Example 3 is the same as that of Example 1, except that the content of element Co in the alloy composition is 0.68%, (7Co+1.3Mo) / (Al+11La)=2.371. The alloy composition prepared in Comparative Example 3 is shown in Table 1, and the properties are shown in Table 2.

[0048] Table 1

[0049]

[0050] Note: The content of each element in the table is in wt%.

[0051] The performance of the nickel-based high-temperature alloys of Examples 1-4 and Comparative Examples 1-3 was tested, and the results are shown in Table 2.

[0052] Table 2

[0053]

[0054] Note: 1. R p0.2 is the room temperature tensile yield strength of the solid solution alloy, R m is the room temperature tensile strength of the solid solution alloy, A is the room temperature tensile elongation of the solid solution alloy;

[0055] 2. E is the elastic modulus of the alloy at room temperature;

[0056] 3. The average oxidation rate is the oxidation rate per unit area of ​​the alloy at 700℃ / 100h. The smaller the value, the better the oxidation resistance;

[0057] 4. During the production process, the alloy needs to undergo forging and rolling, and the forging cracking situation can be used to evaluate the alloy's hot working performance.

[0058] It can be seen from the data in Table 1 and Table 2 that when the content of each element in the alloy is controlled within a certain range, the tensile strength of the prepared alloy reaches more than 1200MPa when stretched at room temperature, the yield strength is within the required range, and the average oxidation rate is reduced to 0.0006g / m 2 h and below, with good oxidation resistance, no cracks appear during forging, good hot working performance, and can meet the requirements of advanced aircraft engine and gas turbine design and use.

[0059] The alloy of Comparative Example 1, (7Co+1.3Mo) / (Al+11La)=0.941<1.10, has a low Cr content and cracks occur during forging.

[0060] The alloy of Comparative Example 2 has a La content of 0.068%≥0.050%, which causes the alloy's hot working properties to deteriorate and severe cracking during forging, failing to meet the preparation requirements. Meanwhile, (7Co+1.3Mo) / (Al+11La)=0.526<1.10, and its oxidation resistance is poor.

[0061] In the alloy of Comparative Example 3, the Co content is 0.68%, (7Co+1.3Mo) / (Al+11La)=2.371>1.50, which significantly improves the yield strength of the alloy and the elastic modulus of the alloy, resulting in increased deformation difficulty and cracking of the alloy during forging, and the yield strength exceeds the upper limit of the design range.

[0062] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A nickel-based high-temperature alloy for brush seals, characterized in that: Calculated in weight percentage, the nickel-based high-temperature alloy includes C: 0.03-0.10%, Mn: 0.01-0.08%, Cr: 19.00-21.00%, Al: 3.20-3.70%, Fe: 2.00-4.00%, Mo: 1.00-3.60%, Co: 0.01-0.50%, La: 0.001-0.05%, and the balance is nickel and unavoidable impurities.

2. The nickel-based high-temperature alloy for brush seal according to claim 1, characterized in that: The weight percentage contents of Co, Mo, Al and La satisfy the relationship 1.10≤(7Co+1.3Mo) / (Al+11La)≤1.

50.

3. The nickel-based high-temperature alloy for brush seal according to claim 1, characterized in that: The weight percentages of Co, Mo, Al and La satisfy the relationship 1.25≤(7Co+1.3Mo) / (Al+11La)≤1.

45.

4. The nickel-based high-temperature alloy for brush seal according to claim 1, characterized in that: The weight percentage of Cr is 19.10-20.10%, the weight percentage of Mo is 1.80-3.05%, the weight percentage of Co is 0.10-0.25%, and the weight percentage of La is 0.001-0.015%.

5. The method for preparing the nickel-based high-temperature alloy for brush seal according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: (1) Cr, Fe, Mo, Ni, and Co raw materials that are not easy to burn are placed in a vacuum induction furnace, heated to melt, cooled, and Al, Mn, C, and La raw materials that are easy to burn are added, and then the temperature is raised, stirred evenly, and then cooled again, and cast in a vacuum environment to obtain an electrode rod; (2) subjecting the electrode rod to vacuum consumable remelting or atmosphere-protected electroslag remelting to obtain a remelted alloy ingot; (3) forging and hot rolling the remelted alloy ingot to obtain a wire rod; (4) subjecting the wire rod to a cold drawing-grinding-heat treatment process cycle, wherein the drawing reduction ratio between each heat treatment is controlled to be 30 to 55%, so that the diameter is gradually reduced to obtain a wire material of target diameter; (5) heat treating the wire material with the target diameter to obtain the high-temperature alloy.

6. The method for preparing a nickel-based high-temperature alloy for brush seal according to claim 5, characterized in that: In step (1), the vacuum degree of the vacuum induction furnace is 0.1-0.5 Pa, the heating temperature is 1540-1600° C., the cooling temperature is 1400-1460° C., the heating temperature is 1540-1600° C., and the cooling temperature is 1420-1490° C.; the size of the electrode rod is Φ140-Φ320 mm.

7. The method for preparing a nickel-based high-temperature alloy for brush seal according to claim 5, characterized in that: In step (2), the size of the remelted alloy ingot is Φ180-Φ380 mm; In step (3), the billet is heated to 1160-1200° C. before forging and hot rolling, and is kept warm for 60-90 minutes before forging and for 35-55 minutes before hot rolling; the size of the wire rod is Ф5-Ф9 mm.

8. The method for preparing a nickel-based high-temperature alloy for brush seal according to claim 5, characterized in that: In step (4), the temperature of the heat treatment is 1050-1080°C, the holding time is calculated dimensionlessly, and the holding time in seconds T of the heat treatment has the following relationship with the wire diameter Φ: when Φ≥0.5mm, 55≤T / Φ≤80; when Φ<0.5mm, 80<T / Φ≤190; the size of the target diameter wire is Φ0.05-Φ0.15mm.

9. The method for preparing a nickel-based high-temperature alloy for brush seal according to claim 5, characterized in that: In step (5), the heat treatment temperature is 800-1000° C., and the insulation time is 0.1-6 min.

10. Use of the nickel-based high-temperature alloy for brush seal according to any one of claims 1 to 4 in aircraft engines, gas turbines or steam turbines.

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