High-temperature-resistant plug valve and preparation method and application thereof

Abstract

The application discloses a high-temperature-resistant plug valve and a preparation method and application thereof, and belongs to the technical field of valves. The plug valve comprises, from inside to outside, a metal base body, a bonding transition layer, a heat insulation layer and a sealing layer. The metal base body comprises, in percentage by weight, Cr 15-22%, Co 10-15%, Mo 8-10%, W 2-4%, Al 1.5-2.5%, Ti 1-2%, Nb 0.5-1.5%, C 0.05-0.15%, B 0.005-0.02%, Zr 0.01-0.1%, and the balance of Ni and inevitable impurities. The bonding transition layer is a NiCrAlYSi alloy. The heat insulation layer is a composite coating of nano ceramic composite powder and CoNiCrAlY alloy powder. The sealing layer is Ti3SiC2. The long-term stable operation of the plug valve in an ultrahigh-temperature environment is realized through optimization of the base body composition and multi-layer coating design, the plug valve has excellent high-temperature oxidation resistance and self-lubricating sealing performance, and can be applied to extreme working conditions in the chemical industry.

Description

Technical Field

[0001] This application relates to a high-temperature resistant slide gate valve, its preparation method and application, belonging to the field of valve technology. Background Technology

[0002] A slide gate valve is a type of valve where the gate and seat are always in tight contact for sealing. It is widely used in power, metallurgy, chemical, environmental protection, and transportation systems for quickly cutting off, isolating, or regulating the flow rate of powder, granular, and flue gas media. Because many processes require operation at high or even ultra-high temperatures and in corrosive atmospheres, stringent requirements are placed on the valve's high-temperature resistance, oxidation resistance, and sealing reliability.

[0003] Traditional slide gate valves typically use stainless steel or high-temperature alloy substrates. While these materials possess a certain degree of high-temperature strength, they still undergo severe oxidation, corrosion, and creep deformation during long-term high-temperature service, leading to valve sealing failure and, in severe cases, even valve malfunction. To address this issue, existing technologies attempt to prepare protective coatings on the substrate surface. However, common single-ceramic coatings (such as alumina and zirconia coatings) are prone to cracking or even peeling during thermal cycling due to the significant difference in thermal expansion coefficients with the metal substrate; while single-metal coatings (such as NiCrAlY coatings) offer limited thermal insulation. Furthermore, frequent opening and closing of the valve's sealing surface at high temperatures easily causes wear or high-temperature adhesion, which can also lead to decreased sealing performance and leakage risks.

[0004] Therefore, developing a slide gate valve with excellent high-temperature mechanical properties, resistance to high-temperature oxidation, and efficient heat insulation is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a high-temperature resistant slide gate valve. This slide gate valve uses a nickel-based alloy material as its base and incorporates a multi-layer heat-resistant coating, which not only possesses excellent mechanical properties but also excellent high-temperature resistance, enabling the slide gate valve to maintain good sealing performance even under ultra-high temperature (>800℃) operating conditions.

[0006] According to one aspect of this application, a high-temperature resistant slide gate valve is provided, which comprises, from the inside out, a metal substrate, an adhesive transition layer, a heat insulation layer, and a sealing layer. The metal matrix comprises, by weight percentage: Cr 15-22%, Co 10-15%, Mo 8-10%, W 2-4%, Al 1.5-2.5%, Ti 1-2%, Nb 0.5-1.5%, C 0.05-0.15%, B 0.005-0.02%, Zr 0.01-0.1%, with the balance being Ni and unavoidable impurities; The bonding transition layer is a NiCrAlYSi alloy; The heat insulation layer is a composite coating of nano-ceramic composite powder and CoNiCrAlY alloy powder. The sealing layer is Ti3SiC2.

[0007] This application adopts a multi-layer composite structure of metal substrate + adhesive layer + heat insulation layer + sealing layer. The synergistic effect between the substrate and each layer enables the slide gate valve to operate stably for a long time in extreme high temperature environments.

[0008] In the metallic matrix, Ni is the main element, providing a stable and highly tough face-centered cubic structure parent phase. The addition of Cr and Al can form a Cr2O3 / Al2O3 composite oxide film, which has the effect of resisting high-temperature oxidation. Co and Ni can form a continuous solid solution, which can significantly improve the solid solution strengthening effect of the alloy. Combined with the composite solid solution strengthening of Mo and W, it can improve the high-temperature strength and microstructure stability of the matrix, enabling the alloy to maintain a high yield strength above 800℃. The addition of Al and Ti can form a γ'-Ni3(Al,Ti) strengthening phase, which further hinders dislocation movement. Nb, Ti, Mo, and W can form a variety of carbides with C, which synergistically strengthen the grain boundaries and the matrix. B and Zr preferentially segregate at the grain boundaries, inhibiting grain boundary carbide coarsening and improving grain boundary bonding.

[0009] The NiCrAlYSi alloy of the bonding transition layer has a similar composition to the substrate and good thermophysical compatibility, which can significantly reduce the difference in thermal expansion coefficient between the substrate and the insulation layer, achieve a good transition effect, and prevent the coating from peeling off during thermal cycling. At the same time, the NiCrAlYSi alloy itself can also form a protective oxide film, blocking oxygen from diffusing into the substrate and protecting the substrate.

[0010] Nanoceramics possess extremely low thermal conductivity, effectively blocking heat transfer. CoNiCrAlY alloy powder, acting as a metallic binder, not only enhances the fracture toughness of the coating and prevents ceramic layer cracking, but also forms thermally grown oxides (TGOs) at high temperatures, providing a high-temperature oxidation barrier. Furthermore, the uniform dispersion of nanoceramic particles within the metal matrix creates numerous ceramic-metal interfaces. These interfaces strongly scatter phonons (the primary charge carriers of heat in solids), resulting in a composite coating that achieves a "1+1>2" thermal insulation effect.

[0011] Ti3SiC2 is a ternary layered ceramic material that combines the high melting point and oxidation resistance of ceramics with the good electrical and thermal conductivity, thermal shock resistance, and excellent self-lubricating properties of metals. During the opening and closing process of a gate valve under high-temperature conditions, the sealing surfaces need to slide relative to each other. The Ti3SiC2 layer provides a low coefficient of friction, preventing the gate valve from seizing at high temperatures. Furthermore, the excellent high-temperature oxidation resistance of the Ti3SiC2 layer ensures reliable sealing during long-term operation at high temperatures.

[0012] Optionally, the mass ratio of Cr to Co in the metal matrix is ​​(1.2-2):1.

[0013] Cr acts as an antioxidant, while Co mainly strengthens the matrix and reduces stacking fault energy. If Co is excessive, harmful topological close-packed phases are easily formed at high temperatures, which impairs toughness and increases costs. If Cr is excessive, the stability of the matrix structure decreases and the precipitation of beneficial γ' phase is inhibited.

[0014] Optionally, the mass ratio of Al to Ti in the metal matrix is ​​(1-1.8):1.

[0015] Al and Ti are key elements for the formation of the γ'-Ni3 (Al, Ti) precipitation strengthening phase. If there is too much Al, the amount of γ' phase may be insufficient; if there is too much Ti, Ti will promote the formation of the harmful η phase (Ni3Ti).

[0016] Optionally, the metal matrix further comprises: Re 0.5-2% and Ta 0.1-0.5%.

[0017] Re is one of the most effective solid solution strengthening elements. Its atomic size is large and its diffusion rate is extremely slow, which can significantly reduce the diffusion coefficient of the matrix and inhibit dislocation climb and grain boundary slip. This can greatly improve the high-temperature creep strength and fatigue resistance of the matrix. At the same time, Re can promote the formation of a denser and more stable oxide film, thus playing an antioxidant role in the matrix.

[0018] Ta can enter the γ' strengthening phase, further improving the high-temperature strength and stability of the γ' strengthening phase; at the same time, Ta easily forms high-melting-point and high-stability MC-type carbides. These carbides precipitate at grain boundaries, which can effectively pin the grain boundaries and inhibit grain growth and the generation of creep cavities.

[0019] Optionally, the nano-ceramic composite powder is a composite powder of Cr2O3, SiO2, and TiO2, wherein the mass fraction of Cr2O3 is 70-85%, the mass fraction of SiO2 is 10-20%, and the mass fraction of TiO2 is 5-10%.

[0020] Cr2O3 has high hardness, high corrosion resistance, and a thermal expansion coefficient similar to that of metals. SiO2, as a glass phase former, can flow and fill pores at high temperatures, improving the density of the coating. TiO2 can improve the toughness of the coating and its wettability with the metal phase. The combination of these three can produce a material with lower thermal conductivity, high thermal shock resistance, and corrosion resistance.

[0021] Optionally, the mass ratio of the nano-ceramic composite powder to the CoNiCrAlY alloy powder is 1:(2-3).

[0022] This mass ratio range ensures that the ceramic phase, as the main insulating phase, is continuously distributed in the composite coating, while the CoNiCrAlY alloy phase, as the toughening skeleton, is uniformly dispersed, thus achieving the optimal balance between thermal insulation and mechanical properties. If the nano-ceramic composite powder content is too high, the coating will be brittle and prone to peeling; if there is too much CoNiCrAlY alloy powder, the thermal insulation effect will decrease. In addition, too much CoNiCrAlY alloy powder will form excessive or overgrown TGO, which will lead to coating peeling and failure.

[0023] Optionally, the thickness of the bonding transition layer is 50-150 μm.

[0024] This thickness range provides good diffusion barrier and stress relief while ensuring a strong bond with the substrate and insulation layer. If it is too thick, it will accumulate internal stress and reduce the bonding strength.

[0025] Optionally, the thickness of the insulation layer is 300-500 μm.

[0026] This is the effective thickness to achieve a significant temperature reduction effect. If it is less than 300μm, the heat insulation effect will be insufficient, and if it is more than 500μm, it will significantly increase the internal stress of the coating and increase the cost.

[0027] Optionally, the thickness of the sealing layer is 80-150 μm.

[0028] This thickness ensures that the sealing surface has sufficient wear-resistant and self-lubricating material to withstand multiple opening and closing operations, while also preventing the coating from affecting the fitting accuracy of the sealing surface due to excessive thickness.

[0029] Optionally, the average particle size of the nano-ceramic composite powder is 50-300 nm, and the average particle size of the CoNiCrAlY alloy powder is 20-50 μm.

[0030] The nano-sized particles of the nano-ceramic composite powder melt more fully and stack more densely during the spraying process, resulting in a coating with extremely low porosity, which significantly improves the heat insulation effect and the ability to resist the penetration of corrosive media.

[0031] The particle size range of CoNiCrAlY alloy powder ensures both good powder flowability and allows the particles to fully melt in the flame, forming a flat, well-spread coating that effectively combines with nano-ceramic particles.

[0032] According to a second aspect of this application, this application provides a method for preparing the high-temperature resistant slide gate valve as described in any of the above claims, comprising the following steps: (1) Preparation of metal matrix S1 adds Co, Cr, Mo, W, Nb and 20-30% Ni into a vacuum induction melting furnace and melts it at 1500-1600℃. Then, it cools down to 1300-1400℃ and adds the remaining Ni, Al, Ti, NiB and Zr. Finally, it heats up to 1450-1500℃ and refines it for 20-30 minutes to obtain the melt. S2 pours the melt into a preheated mold at a casting temperature of 1450-1500℃, and obtains the base blank after cooling and solidification. S3 involves heat-treating the base blank to obtain the metal matrix; (2) Spraying the bonding transition layer The supersonic flame spraying process is adopted, and NiCrAlYSi alloy powder is used as the spraying material to spray the metal substrate. The spraying distance is 300-400mm, the oxygen flow rate is 800-1000L / min, the kerosene flow rate is 20-30L / h, and the powder feeding rate is 50-80g / min. (3) Spraying the heat insulation layer Atmospheric plasma spraying technology is adopted, using a mixture of nano-ceramic composite powder and CoNiCrAlY alloy powder as the spraying material. The spraying current is 500-650A, the voltage is 60-80V, the main gas flow rate is 40-60L / min, the auxiliary gas flow rate is 8-15L / min, the powder feeding rate is 30-50g / min, and the spraying distance is 100-150mm. (4) Spraying a sealing layer The supersonic flame spraying process was adopted, and Ti3SiC2 powder was used as the spraying material to obtain the pretreated body. The spraying distance was 300-400 mm, the oxygen flow rate was 800-1000 L / min, the kerosene flow rate was 20-30 L / h, and the powder feeding rate was 50-80 g / min. (5) Post-processing The pretreated body is heated to 850-950℃ at a heating rate of 3-5℃ / min under an inert atmosphere and held for 1-3 hours. After the heating is completed, it is cooled with the furnace to obtain the final product.

[0033] In step S1, high-melting-point Co, Cr, Mo, W, Nb and some Ni are first melted to form a basic molten pool. After cooling, easily oxidized and volatile Al, Ti, Zr and trace elements are added to form an intermediate alloy (NiB). This step-by-step method can effectively reduce the burn-off of active elements such as Al, Ti and B.

[0034] Holding the coating at 850-950℃ for 1-3 hours in an inert atmosphere promotes further diffusion and bonding of unmelted particles within the coating, releasing residual stress generated during spraying. It also promotes the pre-formation of a continuous, dense TGO layer at the interface between the adhesive and insulation layers, improving the material's oxidation resistance and thermal insulation performance. A heating rate of 3-5℃ / min ensures a uniform temperature rise between the coating and substrate, enhancing the bonding strength between layers and minimizing thermal stress. This prevents cracking or peeling due to thermal shock caused by excessively rapid heating, ensuring the integrity of the coating structure and avoiding excessive TGO growth.

[0035] Optionally, the heat treatment in step S3 involves heating the blank to 1000-1200℃ at a heating rate of 5-10℃ / min and holding it at that temperature for 2-4 hours. After the heat treatment, the blank is air-cooled to room temperature. Then, the blank is heated to 800-900℃ at a heating rate of 5-8℃ / min and held at that temperature for 8-16 hours. After the heat treatment, the blank is air-cooled to room temperature.

[0036] The purpose of the first heating for solution treatment is to fully dissolve the coarse, non-equilibrium phases in the as-cast microstructure into the matrix, thereby homogenizing the alloy composition and allowing for appropriate grain growth to prepare for subsequent aging treatment. After air cooling, a supersaturated solid solution is obtained. The second heating for aging treatment occurs within this temperature range, where the γ' phase -Ni3(Al,Ti) and secondary carbides precipitate uniformly and finely from the supersaturated solid solution, dispersing in the matrix and grain boundaries, thus strengthening the alloy.

[0037] Optionally, Re and Ta are also added to step S1.

[0038] According to a third aspect of this application, this application provides the application of the high-temperature resistant gate valve described in any of the above claims or the gate valve prepared by the preparation method of the high-temperature resistant gate valve described in any of the above claims in the chemical industry.

[0039] The beneficial effects of this application include, but are not limited to: 1. According to the high-temperature resistant gate valve of this application, the application adopts a multi-layer composite structure of metal matrix + adhesive layer + heat insulation layer + sealing layer. The synergistic effect between the matrix and each layer enables the gate valve to operate stably for a long time in extreme high temperature environment.

[0040] 2. According to the high-temperature resistant gate valve of this application, the metal matrix is ​​mainly composed of Ni element, with other elements added in synergy to improve the oxidation resistance and creep resistance, thus solving the problem of easy oxidation and creep failure of the traditional gate valve matrix at ultra-high temperature.

[0041] 3. According to the high-temperature resistant gate valve of this application, the bonding transition layer is used to alleviate the thermophysical mismatch between the substrate and the insulation layer and improve the bonding strength. The insulation layer has both low thermal conductivity and good toughness, and the sealing layer has self-lubricating properties and good high-temperature stability. The synergistic effect of each layer enables the gate valve to operate stably for a long time in extreme high-temperature environments.

[0042] 4. The method for preparing the high-temperature resistant gate valve according to this application includes the steps of melting, forming, and heat treatment of the metal substrate, as well as preparing each functional layer sequentially using supersonic flame spraying and atmospheric plasma spraying, and finally performing overall post-heat treatment to release residual stress. This method has a wide process window and is easy to industrialize. Detailed Implementation

[0043] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0044] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0045] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art.

[0046] Example 1 This embodiment relates to a method for preparing a high-temperature resistant slide gate valve, including the following steps: (1) Preparation of metal matrix S1 adds Co, Cr, Mo, W, Nb and 20% Ni into a vacuum induction melting furnace and melts it at 1500℃. Then, it cools down to 1300℃ and adds the remaining Ni, Al, Ti, NiB and Zr. Finally, it heats up to 1450℃ and refines it for 30 minutes to obtain the melt. By weight percentage, it includes: Cr 20%, Co 15%, Mo 8%, W 2%, Al 1.8%, Ti 1%, Nb 0.5%, C 0.05%, B 0.005%, Zr 0.1%, with the balance being Ni and unavoidable impurities.

[0047] S2 pours the melt into a preheated mold at a casting temperature of 1450℃, and obtains a base blank after cooling and solidification. S3 heats the substrate blank to 1000℃ at a heating rate of 5℃ / min and holds it for 4 hours. After that, it is air-cooled to room temperature. Then, it is heated to 900℃ at a heating rate of 8℃ / min and held for 8 hours. After that, it is air-cooled to room temperature to obtain the metal substrate. (2) Spraying the bonding transition layer A supersonic flame spraying process was adopted, using NiCrAlYSi alloy powder as the spraying material to spray the metal substrate to obtain a bonding transition layer with a thickness of 50μm. The spraying distance was 300mm, the oxygen flow rate was 800L / min, the kerosene flow rate was 20L / h, and the powder feeding rate was 50g / min. (3) Spraying the heat insulation layer An atmospheric plasma spraying process was adopted, using a mixture of nano-ceramic composite powder (70% Cr2O3, 20% SiO2, and 10% TiO2) and CoNiCrAlY alloy powder at a mass ratio of 1:2 as the spraying material to obtain a heat insulation layer with a thickness of 300 μm. The average particle size of the nano-ceramic composite powder was 50 nm, and the average particle size of the CoNiCrAlY alloy powder was 20 μm. The spraying current was 500 A, the voltage was 80 V, the main gas (argon) flow rate was 60 L / min, the auxiliary gas (hydrogen) flow rate was 15 L / min, the powder feeding rate was 50 g / min, and the spraying distance was 150 mm. (4) Spraying a sealing layer The supersonic flame spraying process was adopted, and Ti3SiC2 powder was used as the spraying material to obtain a sealing layer with a thickness of 80μm, thus obtaining a pretreated body. The spraying distance was 400mm, the oxygen flow rate was 1000L / min, the kerosene flow rate was 20L / h, and the powder feeding rate was 50g / min. (5) Post-processing The pretreated body was heated to 850℃ at a heating rate of 3℃ / min under an inert atmosphere and held for 3 hours. After the heating was completed, it was cooled with the furnace to obtain the final product.

[0048] Example 2 This embodiment relates to a method for preparing a high-temperature resistant slide gate valve, including the following steps: (1) Preparation of metal matrix S1 adds Co, Cr, Mo, W, Nb and 30% Ni into a vacuum induction melting furnace and melts it at 1600℃. Then, it cools down to 1400℃ and adds the remaining Ni, Al, Ti, NiB and Zr. Finally, it heats up to 1500℃ and refines it for 20 minutes to obtain the melt. By weight percentage, it includes: Cr 22%, Co 11%, Mo 10%, W 4%, Al 1.5%, Ti 1.5%, Nb 1.5%, C 0.15%, B 0.02%, Zr 0.01%, Re 0.5%, Ta 0.1%, with the balance being Ni and unavoidable impurities.

[0049] S2 pours the melt into a preheated mold at a casting temperature of 1500℃, and obtains a base blank after cooling and solidification. S3 heats the substrate blank to 1200℃ at a heating rate of 10℃ / min and holds it for 2 hours. After that, it is air-cooled to room temperature. Then, it is heated to 800℃ at a heating rate of 5℃ / min and held for 16 hours. After that, it is air-cooled to room temperature to obtain the metal substrate. (2) Spraying the bonding transition layer A supersonic flame spraying process was adopted, using NiCrAlYSi alloy powder as the spraying material to spray the metal substrate to obtain a bonding transition layer with a thickness of 150μm. The spraying distance was 400mm, the oxygen flow rate was 1000L / min, the kerosene flow rate was 30L / h, and the powder feeding rate was 80g / min. (3) Spraying the heat insulation layer An atmospheric plasma spraying process was adopted, using a mixture of nano-ceramic composite powder (85% Cr2O3, 10% SiO2, and 5% TiO2) and CoNiCrAlY alloy powder at a mass ratio of 1:3 as the spraying material to obtain a heat insulation layer with a thickness of 500 μm. The average particle size of the nano-ceramic composite powder was 300 nm, and the average particle size of the CoNiCrAlY alloy powder was 50 μm. The spraying current was 650 A, the voltage was 60 V, the main gas (argon) flow rate was 40 L / min, the auxiliary gas (hydrogen) flow rate was 8 L / min, the powder feeding rate was 30 g / min, and the spraying distance was 100 mm. (4) Spraying a sealing layer The supersonic flame spraying process was used to spray Ti3SiC2 powder as the spraying material to obtain a sealing layer with a thickness of 150μm, resulting in a pretreated body. The spraying distance was 300mm, the oxygen flow rate was 800L / min, the kerosene flow rate was 30L / h, and the powder feeding rate was 80g / min. (5) Post-processing The pretreated body was heated to 950℃ at a heating rate of 5℃ / min under an inert atmosphere and held for 1 hour. After the heating was completed, it was cooled with the furnace to obtain the final product.

[0050] Example 3 This embodiment relates to a method for preparing a high-temperature resistant slide gate valve, including the following steps: (1) Preparation of metal matrix S1 adds Co, Cr, Mo, W, Nb and 30% Ni into a vacuum induction melting furnace and melts it at 1550℃. Then, it cools down to 1350℃ and adds the remaining Ni, Al, Ti, NiB and Zr. Finally, it heats up to 1450℃ and refines it for 30 minutes to obtain the melt. The composition by weight percentage is: Cr 15%, Co 10%, Mo 10%, W 3%, Al 2.5%, Ti 2%, Nb 1%, C 0.1%, B 0.15%, Zr 0.05%, Re 2%, Ta 0.5%, with the balance being Ni and unavoidable impurities.

[0051] S2 pours the melt into a preheated mold at a casting temperature of 1500℃, and obtains a base blank after cooling and solidification. S3 heats the substrate blank to 1100℃ at a heating rate of 8℃ / min and holds it for 3 hours. After that, it is air-cooled to room temperature. Then, it is heated to 850℃ at a heating rate of 6℃ / min and held for 12 hours. After that, it is air-cooled to room temperature to obtain the metal substrate. (2) Spraying the bonding transition layer A supersonic flame spraying process was adopted, using NiCrAlYSi alloy powder as the spraying material to spray the metal substrate to obtain a bonding transition layer with a thickness of 100μm. The spraying distance was 400mm, the oxygen flow rate was 1000L / min, the kerosene flow rate was 30L / h, and the powder feeding rate was 80g / min. (3) Spraying the heat insulation layer An atmospheric plasma spraying process was adopted, using a mixture of nano-ceramic composite powder (80% Cr2O3, 12% SiO2, and 8% TiO2) and CoNiCrAlY alloy powder at a mass ratio of 1:2.2 as the spraying material to obtain a heat insulation layer with a thickness of 400 μm. The average particle size of the nano-ceramic composite powder was 150 nm, and the average particle size of the CoNiCrAlY alloy powder was 35 μm. The spraying current was 650 A, the voltage was 60 V, the main gas (argon) flow rate was 40 L / min, the auxiliary gas (hydrogen) flow rate was 8 L / min, the powder feed rate was 30 g / min, and the spraying distance was 100 mm. (4) Spraying a sealing layer The supersonic flame spraying process was used to spray Ti3SiC2 powder as the spraying material to obtain a sealing layer with a thickness of 120μm, resulting in a pretreated body. The spraying distance was 300mm, the oxygen flow rate was 800L / min, the kerosene flow rate was 30L / h, and the powder feeding rate was 80g / min. (5) Post-processing The pretreated body was heated to 900℃ at a heating rate of 3℃ / min under an inert atmosphere and held for 2 hours. After the heating was completed, it was cooled with the furnace to obtain the final product.

[0052] Example 4 The difference between this embodiment and Embodiment 3 is that the amount of Cr added is 22%, while the rest are the same.

[0053] Example 5 The difference between this embodiment and Embodiment 3 is that the amount of Co added is 15%, while the rest are the same.

[0054] Example 6 The difference between this embodiment and embodiment 3 is that the amount of Al added is 1.5%, while the rest are the same.

[0055] Example 7 The difference between this embodiment and Embodiment 3 is that the amount of Ti added is 1%, while the rest are the same.

[0056] Example 8 The difference between this embodiment and embodiment 3 is that the nano-ceramic composite powder in step (3) does not include TiO2, the mass fraction of SiO2 is 20%, and the rest are the same.

[0057] Example 9 The difference between this embodiment and embodiment 3 is that the nano-ceramic composite powder in step (3) does not contain SiO2, the mass fraction of TiO2 is 20%, and the rest are the same.

[0058] Example 10 The difference between this embodiment and embodiment 3 is that the mass ratio of nano-ceramic composite powder to CoNiCrAlY alloy powder in step (3) is 1:1.6, while the rest are the same.

[0059] Example 11 The difference between this embodiment and embodiment 3 is that the mass ratio of nano-ceramic composite powder to CoNiCrAlY alloy powder in step (3) is 1:3.3, while the rest are the same.

[0060] Example 12 The difference between this embodiment and Embodiment 3 is that the thickness of the bonding transition layer is 200 μm, while the rest are the same.

[0061] Example 13 The difference between this embodiment and Embodiment 3 is that the thickness of the insulation layer is 550 μm, while the rest are the same.

[0062] Example 14 The difference between this embodiment and Embodiment 3 is that the thickness of the sealing layer is 200μm, while the rest are the same.

[0063] Example 15 The difference between this embodiment and embodiment 3 is that there is no secondary heating in step S3, and the holding time for the first heating is 15 hours, while the rest are the same.

[0064] Comparative Example 1 The difference between this comparative example and Example 3 is that C is not added; all other aspects are the same.

[0065] Comparative Example 2 The difference between this comparative example and Example 3 is that B is not added; all other aspects are the same.

[0066] Comparative Example 3 The difference between this comparative example and Example 3 is that Zr is not added; all other aspects are the same.

[0067] Comparative Example 4 The difference between this comparative example and Example 3 is that the amount of Mo added is 15%, while the rest are the same.

[0068] Comparative Example 5 The difference between this comparative example and Example 3 is that the amount of Al added is 3%, while the rest are the same.

[0069] Comparative Example 6 The difference between this comparative example and Example 3 is that the amount of Ti added is 3%, while the rest are the same.

[0070] Comparative Example 7 The difference between this comparative example and Example 3 is that CoNiCrAlY alloy powder is not added in step (3), but all other steps are the same.

[0071] Comparative Example 8 The difference between this comparative example and Example 3 is that no nano-ceramic composite powder is added in step (3), while the rest are the same.

[0072] Comparative Example 9 The difference between this comparative example and Example 3 is that step (2) is omitted, while the rest are the same.

[0073] Comparative Example 10 The difference between this comparative example and Example 3 is that step (3) is omitted, while the rest are the same.

[0074] Comparative Example 11 The difference between this comparative example and Example 3 is that step (4) is omitted, while the rest are the same.

[0075] Comparative Example 12 The difference between this comparative example and Example 3 is that the heating rate in step (5) is 8°C / min, while the rest are the same.

[0076] Test Example 1 After selecting samples of the high-temperature resistant gate valves prepared in the above embodiments and comparative examples, mechanical properties were tested. The mechanical property testing method was carried out in accordance with the standard GB / T 228.1-2021, and the results are shown in Table 1.

[0077] Table 1

[0078] Test Example 2 The high-temperature resistant slide gate valves prepared in the above embodiments and comparative examples were repeatedly opened and closed 1000 times at 1000℃ (fully open-fully closed constitutes one cycle, with a rate of 5 times / minute). Mechanical and sealing performance tests were then conducted. The mechanical performance testing method followed standard GB / T 228.1-2021, and the sealing performance testing followed standard GB / T 26480. The test results are shown in Table 2. The tensile strength change rate was calculated as: |(tensile strength after 1000 opening and closing cycles - tensile strength before 1000 opening and closing cycles)| / tensile strength before 1000 opening and closing cycles × 100%. The yield strength change rate was calculated as: |(yield strength after 1000 opening and closing cycles - yield strength before 1000 opening and closing cycles)| / yield strength before 1000 opening and closing cycles × 100%.

[0079] Table 2

[0080] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A high-temperature resistant slide gate valve, characterized in that, The slide gate valve consists of, from the inside out, a metal substrate, an adhesive transition layer, a heat insulation layer, and a sealing layer. The metal matrix comprises, by weight percentage: Cr 15-22%, Co 10-15%, Mo 8-10%, W 2-4%, Al 1.5-2.5%, Ti 1-2%, Nb 0.5-1.5%, C 0.05-0.15%, B 0.005-0.02%, Zr 0.01-0.1%, with the balance being Ni and unavoidable impurities; The bonding transition layer is a NiCrAlYSi alloy; The heat insulation layer is a composite coating of nano-ceramic composite powder and CoNiCrAlY alloy powder. The sealing layer is Ti3SiC2.

2. The high-temperature resistant slide gate valve according to claim 1, characterized in that, The mass ratio of Cr to Co in the metal matrix is ​​(1.2-2):1; and / or The mass ratio of Al to Ti in the metal matrix is ​​(1-1.8):

1.

3. The high-temperature resistant slide gate valve according to claim 1, characterized in that, The metal matrix also includes: Re 0.5-2% and Ta 0.1-0.5%.

4. The high-temperature resistant slide gate valve according to claim 1, characterized in that, The nano-ceramic composite powder is a composite powder of Cr2O3, SiO2, and TiO2, wherein the mass fraction of Cr2O3 is 70-85%, the mass fraction of SiO2 is 10-20%, and the mass fraction of TiO2 is 5-10%; and / or The mass ratio of the nano-ceramic composite powder to the CoNiCrAlY alloy powder is 1:(2-3).

5. The high-temperature resistant slide gate valve according to claim 1, characterized in that, The thickness of the bonding transition layer is 50-150 μm; and / or The thickness of the insulation layer is 300-500 μm; and / or The thickness of the sealing layer is 80-150 μm.

6. The high-temperature resistant slide gate valve according to claim 1, characterized in that, The average particle size of the nano-ceramic composite powder is 50-300 nm, and the average particle size of the CoNiCrAlY alloy powder is 20-50 μm.

7. The method for preparing the high-temperature resistant slide gate valve according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Preparation of metal matrix S1 adds Co, Cr, Mo, W, Nb and 20-30% Ni into a vacuum induction melting furnace and melts it at 1500-1600℃. Then, it cools down to 1300-1400℃ and adds the remaining Ni, Al, Ti, NiB and Zr. Finally, it heats up to 1450-1500℃ and refines it for 20-30 minutes to obtain the melt. S2 pours the melt into a preheated mold at a casting temperature of 1450-1500℃, and obtains the base blank after cooling and solidification. S3 involves heat-treating the base blank to obtain the metal matrix; (2) Spraying the bonding transition layer The supersonic flame spraying process is adopted, and NiCrAlYSi alloy powder is used as the spraying material to spray the metal substrate. The spraying distance is 300-400mm, the oxygen flow rate is 800-1000L / min, the kerosene flow rate is 20-30L / h, and the powder feeding rate is 50-80g / min. (3) Spraying the heat insulation layer Atmospheric plasma spraying technology is adopted, using a mixture of nano-ceramic composite powder and CoNiCrAlY alloy powder as the spraying material. The spraying current is 500-650A, the voltage is 60-80V, the main gas flow rate is 40-60L / min, the auxiliary gas flow rate is 8-15L / min, the powder feeding rate is 30-50g / min, and the spraying distance is 100-150mm. (4) Spraying a sealing layer The supersonic flame spraying process was adopted, and Ti3SiC2 powder was used as the spraying material to obtain the pretreated body. The spraying distance was 300-400 mm, the oxygen flow rate was 800-1000 L / min, the kerosene flow rate was 20-30 L / h, and the powder feeding rate was 50-80 g / min. (5) Post-processing The pretreated body is heated to 850-950℃ at a heating rate of 3-5℃ / min under an inert atmosphere and held for 1-3 hours. After the heating is completed, it is cooled with the furnace to obtain the final product.

8. The method for preparing the high-temperature resistant slide gate valve according to claim 7, characterized in that, The heat treatment described in step S3 involves heating the blank to 1000-1200℃ at a heating rate of 5-10℃ / min and holding it at that temperature for 2-4 hours. After the heat treatment, the blank is air-cooled to room temperature. Then, the blank is heated to 800-900℃ at a heating rate of 5-8℃ / min and held at that temperature for 8-16 hours. After the heat treatment, the blank is air-cooled to room temperature.

9. The method for preparing the high-temperature resistant slide gate valve according to claim 7, characterized in that, Re and Ta are also added in step S1.

10. The application of the high-temperature resistant gate valve according to any one of claims 1-6 or the high-temperature resistant gate valve according to any one of claims 7-9 in the chemical industry.

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