Nickel-based corrosion-resistant alloy and preparation process thereof

Abstract

The invention discloses a nickel-based corrosion-resistant alloy and a preparation process thereof, belongs to the technical field of nickel-based alloys, and aims to solve the technical problem that the corrosion resistance of the nickel-based alloy in the prior art needs to be further enhanced. The preparation process of the nickel-based corrosion-resistant alloy comprises the following steps: smelting nickel-based alloy components by adopting a vacuum induction and electroslag remelting smelting process to obtain a nickel-based alloy blank; forging and rolling the nickel-based alloy blank into a plate, and carrying out solution treatment, intermediate heat treatment and desensitization heat treatment to obtain a nickel-based alloy plate; the nickel-based alloy plate is pretreated, and the pretreated nickel-based alloy plate is obtained; spraying the sol on the surface of the pretreated nickel-based alloy plate to form a wet film; and under the nitrogen atmosphere, heat treatment is conducted, furnace cooling is conducted to the room temperature, and the nickel-based corrosion-resistant alloy is obtained. The nickel-based corrosion-resistant alloy prepared through the method has good high-temperature corrosion resistance, durability and stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nickel-based alloys, in particular to a nickel-based corrosion-resistant alloy and a preparation process thereof. BACKGROUND

[0002] Nickel-based high-temperature alloys have good high-temperature resistance and corrosion resistance, and are the most widely used and most concerned high-temperature alloys. They have good mechanical properties, plasticity and toughness, excellent creep fatigue resistance, excellent oxidation and corrosion resistance, and organizational stability, and are indispensable high-temperature structural materials for engine and gas turbine turbine blades in the fields of aerospace and engineering. However, when such high-performance materials are applied to marine environments, they face complex corrosion challenges. In the operating scenario of marine gas turbines, turbine blades are prone to hot corrosion due to long-term exposure to high-temperature and salt spray environments, which not only significantly reduces equipment efficiency, but also significantly increases maintenance costs. At the same time, in high-salinity marine atmospheric environments, corrosion continues to erode blade materials, further shortening equipment service life. In addition, equipment such as ships and aircraft parked in coastal environments, even in non-operating state, their turbine blades will still be affected by the harsh marine environment and produce corrosion hazards. These corrosion problems caused by marine environments, with high prevention costs and great technical difficulties, have become a key bottleneck restricting the reliability of marine gas turbines and related equipment.

[0003] Chinese patent CN113265566B discloses a kind of corrosion-resistant nickel-based alloy, wherein the corrosion-resistant nickel-based alloy includes: C0.01%, Si0.09%, Mn0.11%, P0.005%, S0.001%, Cr22.1%, Mo8.9%, Cu3.3%, Nb0.1%, A10.12%, Ti0.06%, N0.14%, Fe4.2%, Pb, Sn, As, Sb, Bi are not greater than 0.001%, the total is not greater than 0.005%, by weight percentage; the rest is Ni and unavoidable impurities; the hot corrosion performance of the corrosion-resistant nickel-based alloy prepared by the invention needs to be improved. SUMMARY

[0004] The purpose of the present application is to provide a kind of nickel-based corrosion-resistant alloy and preparation process thereof, to solve the technical problems that the corrosion resistance of nickel-based alloy in prior art needs to be further strengthened.

[0005] In order to achieve the above purpose, the present application provides a preparation process of a nickel-based corrosion-resistant alloy, comprising the following steps:

[0006] Step (1) melt the nickel-based alloy components using vacuum induction and electroslag remelting smelting process to obtain nickel-based alloy billets;

[0007] Step (2) forging and rolling the nickel-based alloy blank into a plate, carrying out solid solution treatment, intermediate heat treatment, and desensitization heat treatment to obtain a nickel-based alloy plate;

[0008] Step (3) pretreating the nickel-based alloy plate to obtain a pretreated nickel-based alloy plate;

[0009] Step (4) spraying the sol on the surface of the pretreated nickel-based alloy plate to form a wet film; carrying out heat treatment under a nitrogen atmosphere and cooling to room temperature in the furnace to obtain a nickel-based corrosion-resistant alloy;

[0010] Preferably, the nickel-based alloy composition includes Cr 20-25%, Mo 9-11%, Al 4.5-6.5%, Ta 1-2%, W 2-3%, Nb 0.8-1.5%, Re 1-2%, Ru 1-2%, La 0.05-0.1%, Hf 0.5-1%, C≤0.01%, Mn≤0.2%, and the balance of Ni, by mass percentage.

[0011] Preferably, the preparation method of the sol includes the following steps:

[0012] The Ce source solution and the Y source solution are mixed, citric acid is added, stirring is performed, temperature is raised, stirring is performed, cooling is performed, ammonia water is used to adjust the pH, and aging is performed to obtain the sol.

[0013] Preferably, in step (1), the vacuum induction and electroslag remelting smelting process is as follows: in the first step, vacuum induction melting is performed, the nickel-based alloy composition is taken out according to the mass percentage, is loaded into a magnesia crucible, the vacuum degree is kept at ≤10 -2 Pa, an induction heating system is started, the melting temperature is controlled at 1500-1600℃ and the holding time is 30-60 min, during which Ar gas is blown to remove inclusions; in the second step, electroslag remelting is performed, the slag system is composed of CaF2, Al2O3 and CaO with a mass ratio of 40:30:30, the electrode diameter is 150 mm, the current density is 5 A / cm 2 , the melting speed is 0.5-0.8 kg / min, and the slag pool temperature is 1550-1600℃; in the cooling stage of the electroslag remelting, the cooling speed is 2-5℃ / min to cool to room temperature.

[0014] Preferably, in step (2), the specific process of forging and rolling is as follows: in the first step, a forging process is performed, specifically, the nickel-based alloy blank is heated at 1100-1200℃ for 3.5-4.5 h, multiple forging is adopted, the forging ratio is 4-5, and a forged blank is obtained; in the second step, a rolling process is performed, the forged blank is reheated to 1150-1180℃ and held for 2.6-3.2 h, multiple passes of hot rolling are adopted, the final rolling temperature is controlled at 850-875℃, the total reduction is ≥80%, and the final rolling is performed into a plate.

[0015] Preferably, in step (2), the solution treatment conditions are: keeping the temperature at 1180-1220° C. for 1-1.2 hours.

[0016] Preferably, in step (2), the intermediate heat treatment conditions are: keeping warm at a temperature of 780-900°C for 2-4 hours.

[0017] Preferably, in step (2), the desensitization heat treatment conditions are: desensitization heat treatment at 650-700°C for 1-2h.

[0018] Preferably, in step (3), the method for preparing the pretreated nickel-based alloy plate comprises the following steps:

[0019] The surface of the nickel-based alloy plate was coarsely ground with 200#, 400#, 600# and 800# SiC sandpaper in sequence and polished with a polishing machine until the surface roughness Ra ≤ 0.2 μm, washed with anhydrous ethanol solution, dried, washed with a 0.01 mol / L NaOH aqueous solution at 50°C, rinsed with deionized water, washed with a 0.01 mol / L nitric acid aqueous solution at 50°C for 5 minutes, rinsed with deionized water, and dried to obtain the pretreated nickel-based alloy plate.

[0020] Preferably, in step (4), the S content in the nickel-based corrosion-resistant alloy is ≤0.0001%, and the P content is ≤0.0001%.

[0021] Preferably, in step (4), the heat treatment conditions are: room temperature as the initial temperature, heating to 130-150°C at a rate of 5°C / min and keeping warm for 0.4-0.6h; heating to 300-350°C at a rate of 2°C / min and keeping warm for 0.8-1.2h; heating to 620-650°C at a rate of 2°C / min and keeping warm for 1.5-2h.

[0022] Preferably, in step (4), the Ce source solution is prepared as follows: 8 g of cerium nitrate hexahydrate [Ce(NO3)3·6H2O] is dissolved in 25 mL of 30% ethanol aqueous solution and stirred to obtain a Ce source solution; the Y source solution is prepared as follows: 1.2 g of yttrium nitrate hexahydrate [Y(NO3)3·6H2O] is dissolved in 10 mL of deionized water to obtain a Y source solution; wherein the mass ratio of the Ce source solution, the Y source solution, the citric acid and the ammonia solution is (30-40):(10-15):(8-10):(2-6). Preferably, in step (4), the stirring rate is 80-100 r / min, the stirring time is 40-60 min, and the heating temperature is 60-80°C.

[0023] Preferably, in step (4), the aging conditions are: aging at a temperature of 25-30°C for 20-24 hours.

[0024] Preferably, in the step (4), the concentration of the ammonia water is 0.01 mol / L.

[0025] Preferably, in the step (4), the pH range is 6.7-7.2.

[0026] Preferably, a nickel-based corrosion-resistant alloy is prepared by the preparation process of the nickel-based corrosion-resistant alloy.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] 1. In the present application, Cr contained in the nickel-based alloy matrix plays a role of solid solution strengthening and improving comprehensive corrosion performance, and forms a Cr2O3 type oxide film to resist the erosion of oxidizing media (such as O2, SO4 2- ); Mo is a solid solution strengthening element in the nickel-based alloy and can form a MoO2 / MoO3 protective film in non-oxidizing acid to improve the pitting resistance; Al generates Al2O3 inner layer oxide film at high temperature, which cooperates with Cr2O3 to enhance the oxidation resistance and corrosion resistance; Re / Ru can refine the γ' phase (Ni3Al) and inhibit the coarsening at high temperature, thereby improving the hot strength; La / Hf reduces the grain boundary energy and inhibits intergranular corrosion; Ta / Nb forms MC type carbide to inhibit the precipitation of harmful Cr-rich carbide (such as M 23 C6) at the grain boundary, thereby avoiding the formation of Cr-poor zone near the grain boundary and improving the intergranular corrosion resistance; W, as a solid solution strengthening element, improves the creep resistance of the matrix.

[0029] 2. The present application constructs a Ce / Y composite oxide coating, CeO2 at high temperature through valence state conversion and its accompanying oxygen vacancy formation and migration mechanism, regulates oxygen ion diffusion, inhibits the growth rate of the oxide film, avoids the loosening and cracking of the film layer caused by too fast growth, especially in high temperature and strong corrosion environment, the rapid growth will cause cracking due to internal stress accumulation, and good growth rate is beneficial to the formation of dense and stable coating; CeO2 maintains a certain oxygen potential on the surface, which is beneficial to the formation of Cr2O3 under moderate oxygen partial pressure, and is beneficial to the repair function of the oxide film and prolongs the corrosion resistance time; it can also react with SO4 2- in the molten salt to generate Ce2(SO4)3, prevent the formation of sulfide, and prolong the penetration time of molten salt corrosion. Y2O3 in the Ce / Y composite oxide coating can refine the oxide film grain and improve the denseness of the film layer; and by fixing Cl-, YCl3 is formed to inhibit the expansion of pitting. The Ce / Y composite oxide coating hinders the diffusion of corrosion elements such as O, S and Cl, inhibits the volatilization of metal elements and the formation of low melting point salt; provides grain boundary pinning effect, stabilizes high temperature structure, and delays the recrystallization process induced by corrosion.

[0030] 3.The present application optimizes the element composition of the nickel-based alloy, so that the elements produce a synergistic effect, and the nickel-based alloy has good heat corrosion resistance; by constructing a good high-temperature coating system, the excellent performance of the nickel-based alloy in a high-temperature and strong corrosion environment is further improved. The preparation process of the nickel-based corrosion-resistant alloy provided by the present application adopts vacuum induction and electroslag remelting smelting process to obtain a nickel-based alloy blank with uniform composition, and then a Ce / Y composite oxide coating is prepared, so that the nickel-based alloy has good high-temperature oxidation resistance and high-temperature heat corrosion resistance, which is beneficial to long-term use. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The preparation process flow chart of the nickel-based corrosion-resistant alloy in the present application is shown in the figure.

[0032] Figure 2 The figure is a hot corrosion kinetics curve of the nickel-based corrosion-resistant alloy prepared in Example 2-1, Example 2-2, Example 2-3 and Comparative Examples 1-1 to 1-5. DETAILED DESCRIPTION

[0033] The technical solutions of the present application will be described below in conjunction with the embodiments, obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0034] Example 1-1

[0035] The present embodiment provides a preparation method of a pretreated nickel-based alloy plate, comprising the following steps:

[0036] S1: smelt the nickel-based alloy composition by vacuum induction and electroslag remelting smelting process to obtain a nickel-based alloy blank;

[0037] During vacuum induction smelting, the nickel-based alloy composition is taken out by mass percentage and loaded into a magnesium crucible, the vacuum degree is ≤10 -2 Pa, induction heating to 1500℃ for 60min, Ar gas stirring to remove impurities; the slag system of electroslag remelting is composed of CaF2, Al2O3 and CaO with a mass ratio of 40:30:30, the electrode diameter is 150mm, the current density is 5A / cm 2 , the melting speed is 0.5kg / min, and the slag pool temperature is 1550℃, and the cooling stage is reduced to room temperature at a rate of 2℃ / min;

[0038] The nickel-based alloy composition includes, in terms of mass percentage, Cr 20%, Mo 9%, Al: 4.5%, Ta 1%, W 2%, Nb 0.8%, Re 1%, Ru 1%, La 0.05%, Hf 0.5%, C≤0.01%, Mn≤0.2%, and the balance of Ni;

[0039] S2: forging and rolling the nickel-based alloy blank into a plate, heat preservation at 1180℃ for 1.2h, intermediate heat treatment at 780℃ for 4h, and desensitization heat treatment at 650℃ for 2h, to obtain a nickel-based alloy plate;

[0040] The forging and rolling specifically includes: first, heating and preserving the nickel-based alloy blank at 1100℃ for 4.5h, forging for multiple times, with a forging ratio of 4, to obtain a forged blank; and then, re-heating the forged blank to 1150℃ and preserving for 3.2h, starting rolling at a temperature≥1100℃, multi-pass hot rolling, with a final rolling temperature of 850℃ and a total reduction of≥80%, to obtain the nickel-based alloy plate;

[0041] S3: roughening the surface of the nickel-based alloy plate with 200#, 400#, 600# and 800# SiC sandpaper in sequence, polishing with a polishing machine to a surface roughness Ra≤0.2μm, cleaning with anhydrous ethanol, drying, cleaning with 0.01mol / L NaOH aqueous solution at 50℃ for 5min, rinsing with deionized water, cleaning with 0.01mol / L nitric acid aqueous solution at 50℃ for 5min, rinsing with deionized water, and drying, to obtain the pretreated nickel-based alloy plate.

[0042] Embodiment 1-2

[0043] The embodiment provides a preparation method of a pretreated nickel-based alloy plate, including the following steps:

[0044] S1: smelting the nickel-based alloy composition by a vacuum induction and electroslag remelting process, to obtain a nickel-based alloy blank;

[0045] In the vacuum induction smelting, the nickel-based alloy composition is taken out by mass percentage and loaded into a magnesia crucible, with a vacuum degree≤10 -2 Pa, induction heating to 1550℃ for 45min, and Ar gas stirring for impurity removal; the slag system for the electroslag remelting includes CaF2, Al2O3 and CaO in a mass ratio of 40:30:30, the electrode diameter is 150mm, the current density is 5A / cm 2 , the melting speed is 0.65kg / min, and the slag pool temperature is 1575℃, and the cooling stage is reduced to room temperature at a rate of 3.5℃ / min;

[0046] The nickel-based alloy composition includes, in terms of mass percentage, Cr 22.5%, Mo 10%, Al 5.5%, Ta 1.5%, W 2.5%, Nb 1.15%, Re 1.5%, Ru 1.5%, La 0.07%, Hf 0.7%, C≤0.01%, Mn≤0.2%, and the balance of Ni;

[0047] S2: forging and rolling the nickel-based alloy blank into a plate, heat preservation at 1200℃ for 1.1h, intermediate heat treatment at 840℃ for 3h, desensitization heat treatment at 675℃ for 1.5h, to obtain a nickel-based alloy plate;

[0048] The forging and rolling specifically includes: first heating the nickel-based alloy blank at 1150℃ for 4h, forging for multiple times, with a forging ratio of 4, to obtain a forged blank; and then re-heating the forged blank to 1165℃ and heat preservation for 2.9h, starting rolling at a temperature≥1100℃, multi-pass hot rolling, with a final rolling temperature of 875℃ and a total reduction of≥80%, to obtain the nickel-based alloy plate;

[0049] S3: sequentially roughening the surface of the nickel-based alloy plate with 200#, 400#, 600# and 800# SiC sandpaper, polishing with a polishing machine to a surface roughness Ra≤0.2μm, cleaning with anhydrous ethanol, drying, cleaning with 0.01mol / L NaOH aqueous solution at 50℃ for 5min, rinsing with deionized water, cleaning with 0.01mol / L nitric acid aqueous solution at 50℃ for 5min, rinsing with deionized water, and drying, to obtain the pretreated nickel-based alloy plate.

[0050] Examples 1-3

[0051] The embodiment provides a preparation method of a pretreated nickel-based alloy plate, including the following steps:

[0052] S1: smelting the nickel-based alloy composition by a vacuum induction and electroslag remelting process, to obtain a nickel-based alloy blank;

[0053] In the vacuum induction smelting, the nickel-based alloy composition is taken out by mass percentage and loaded into a magnesia crucible, the vacuum degree is≤10 -2 Pa, induction heating to 1600℃ for 30min, and Ar gas stirring for impurity removal; the slag system of the electroslag remelting includes CaF2, Al2O3 and CaO in a mass ratio of 40:30:30, the electrode diameter is 150mm, the current density is 5A / cm 2 , the melting speed is 0.8kg / min, and the slag pool temperature is 1600℃, and the cooling stage is reduced to room temperature at a rate of 5℃ / min;

[0054] The nickel-based alloy composition includes, in terms of mass percentage, Cr 25%, Mo 11%, Al: 6.5%, Ta 2%, W 3%, Nb 1.5%, Re 2%, Ru 2%, La 0.1%, Hf 1%, C≤0.01%, Mn≤0.2%, and the balance of Ni;

[0055] S2: forging and rolling the nickel-based alloy blank into a plate, heat preservation at 1220℃ for 1h, intermediate heat treatment at 900℃ for 2h, desensitization heat treatment at 700℃ for 1h, to obtain a nickel-based alloy plate;

[0056] The forging and rolling specifically includes: first heating the nickel-based alloy blank at 1200℃ for 3.5h, forging for multiple times, with a forging ratio of 4, to obtain a forged blank; then re-heating the forged blank to 1180℃ and heat preservation for 2.6h, starting rolling at a temperature≥1100℃, multi-pass hot rolling, final rolling temperature 900℃, total reduction≥80%, to obtain the nickel-based alloy plate;

[0057] S3: rough grinding the surface of the nickel-based alloy plate with 200#, 400#, 600# and 800# SiC sandpaper in sequence, polishing with a polishing machine to a surface roughness Ra≤0.2μm, washing with anhydrous ethanol, drying, washing with 0.01mol / L NaOH aqueous solution at 50℃ for 5min, rinsing with deionized water, washing with 0.01mol / L nitric acid aqueous solution at 50℃ for 5min, rinsing with deionized water, drying, to obtain the pretreated nickel-based alloy plate.

[0058] Example 2-1

[0059] The pretreated nickel-based alloy plate used in this example is prepared from the pretreated nickel-based alloy plate prepared in Example 1-1.

[0060] This example provides a preparation process of a nickel-based corrosion-resistant alloy, specifically including the following steps:

[0061] The sol is sprayed on the surface of the pretreated nickel-based alloy plate to form a wet film; under a nitrogen atmosphere, the temperature is raised from room temperature to 130℃ at a rate of 5℃ / min, heat preservation for 0.6h, the temperature is raised to 300℃ at a rate of 2℃ / min, heat preservation for 1.2h, the temperature is raised to 620℃ at a rate of 2℃ / min, heat preservation for 2h, and the furnace is cooled to room temperature, to obtain a nickel-based corrosion-resistant alloy;

[0062] The S content in the nickel-based corrosion-resistant alloy is≤0.0001%, and the P content is≤0.0001%;

[0063] The preparation method of the sol includes the following steps:

[0064] The Ce source solution and the Y source solution are mixed, stirred at a rotation speed of 120 r / min for 14 min, citric acid is added, stirred at a rotation speed of 80 r / min for 60 min, stirred at a rotation speed of 150 r / min at 60 ℃ for 4 h, cooled to room temperature, 0.01 mol / L ammonia water is used to adjust the pH to 6.7, and the sol is obtained by aging at 25 ℃ for 24 h;

[0065] The mass ratio of the Ce source solution, the Y source solution, the citric acid, and the ammonia water is 30:10:8:2.

[0066] The preparation of the Ce source solution is as follows: 8 g of cerium nitrate hexahydrate [Ce(NO3)3·6H2O] is dissolved in 25 mL of an ethanol aqueous solution with a mass concentration of 30%, and stirred to obtain the Ce source solution.

[0067] The preparation of the Y source solution is as follows: 1.2 g of yttrium nitrate hexahydrate [Y(NO3)3·6H2O] is dissolved in 10 mL of deionized water to obtain the Y source solution.

[0068] Example 2-2

[0069] The pretreated nickel-based alloy plate used in this example is prepared from the pretreated nickel-based alloy plate prepared in Example 1-1.

[0070] This example provides a preparation process of a nickel-based corrosion-resistant alloy, which specifically comprises the following steps:

[0071] The sol is sprayed on the surface of the pretreated nickel-based alloy plate to form a wet film; under a nitrogen atmosphere, the temperature is increased to 140 ℃ at a rate of 5 ℃ / min from room temperature, and then the temperature is kept for 0.5 h, the temperature is increased to 325 ℃ at a rate of 2 ℃ / min, and then the temperature is kept for 1 h, the temperature is increased to 635 ℃ at a rate of 2 ℃ / min, and then the temperature is kept for 1.7 h, and then the temperature is cooled to room temperature in the furnace, to obtain a nickel-based corrosion-resistant alloy.

[0072] The content of S in the nickel-based corrosion-resistant alloy is ≤0.0001%, and the content of P is ≤0.0001%.

[0073] The preparation method of the sol comprises the following steps:

[0074] The Ce source solution and the Y source solution are mixed, stirred at a rotation speed of 140 r / min for 12 min, citric acid is added, stirred at a rotation speed of 90 r / min for 50 min, stirred at a rotation speed of 175 r / min at 70 ℃ for 3 h, cooled to room temperature, 0.01 mol / L ammonia water is used to adjust the pH to 7, and the sol is obtained by aging at 27 ℃ for 22 h.

[0075] The mass ratio of the Ce source solution, the Y source solution, the citric acid, and the ammonia water is 35:12:9:4.

[0076] The preparation of the Ce source solution is as follows: 8 g of cerium nitrate hexahydrate [Ce(NO3)3·6H2O] is dissolved in 25 mL of an ethanol aqueous solution with a mass concentration of 30%, and stirred to obtain the Ce source solution.

[0077] The preparation of the Y source solution is as follows: 1.2 g of yttrium nitrate hexahydrate [Y(NO3)3·6H2O] is dissolved in 10 mL of deionized water to obtain the Y source solution.

[0078] Example 2-3

[0079] The pretreated nickel-based alloy plate used in this example is prepared from the pretreated nickel-based alloy plate prepared in Example 1-1.

[0080] This example provides a preparation process of a nickel-based corrosion-resistant alloy, which specifically comprises the following steps:

[0081] The sol is sprayed on the surface of the pretreated nickel-based alloy plate to form a wet film; under a nitrogen atmosphere, the temperature is raised from room temperature to 150℃ at a rate of 5℃ / min, and then the temperature is raised to 350℃ at a rate of 2℃ / min and kept for 0.8h, and then the temperature is raised to 650℃ at a rate of 2℃ / min and kept for 1.5h, and then the temperature is cooled to room temperature in the furnace, to obtain a nickel-based corrosion-resistant alloy;

[0082] In the nickel-based corrosion-resistant alloy, the content of S is ≤0.0001%, and the content of P is ≤0.0001%.

[0083] The preparation method of the sol comprises the following steps:

[0084] The Ce source solution and the Y source solution are mixed and stirred at a speed of 160 r / min for 10 min, citric acid is added, and the mixture is stirred at a speed of 100 r / min for 40 min, then the mixture is stirred at a speed of 80 r / min for 2h at 80℃, and then the mixture is cooled to room temperature, the pH value is adjusted to 7.2 by 0.01 mol / L ammonia water, and the mixture is aged at a temperature of 30℃ for 20h to obtain the sol.

[0085] The mass ratio of the Ce source solution, the Y source solution, the citric acid and the ammonia water is 40:15:10:6.

[0086] The preparation of the Ce source solution is as follows: 8 g of cerium nitrate hexahydrate [Ce(NO3)3·6H2O] is dissolved in 25 mL of an ethanol aqueous solution with a mass concentration of 30%, and stirred to obtain the Ce source solution.

[0087] The preparation of the Y source solution is as follows: 1.2 g of yttrium nitrate hexahydrate [Y(NO3)3·6H2O] is dissolved in 10 mL of deionized water to obtain the Y source solution.

[0088] Comparative Example 1-1

[0089] The pretreated nickel-based alloy plate used in the embodiment is prepared from the pretreated nickel-based alloy plate prepared in Example 1-1.

[0090] The present comparative example provides a preparation process of a nickel-based corrosion-resistant alloy, specifically comprising the following steps:

[0091] The sol is sprayed on the surface of the pretreated nickel-based alloy plate to form a wet film; under a nitrogen atmosphere, the temperature is increased from room temperature to 130℃ at a rate of 5℃ / min, and then the temperature is kept for 0.6h, the temperature is increased to 300℃ at a rate of 2℃ / min, and then the temperature is kept for 1.2h, the temperature is increased to 620℃ at a rate of 2℃ / min, and then the temperature is kept for 2h, and then the temperature is cooled to room temperature in the furnace, to obtain a nickel-based corrosion-resistant alloy;

[0092] In the nickel-based corrosion-resistant alloy, the content of S is ≤0.0001%, and the content of P is ≤0.0001%.

[0093] The preparation method of the sol comprises the following steps:

[0094] 1.2g yttrium nitrate hexahydrate [Y(NO3)3·6H2O] is dissolved in 10mL deionized water to obtain a Y source solution, which is stirred at a speed of 120r / min for 14min, citric acid is added, and the mixture is stirred at a speed of 80r / min for 60min, then the mixture is stirred at a speed of 150r / min for 4h at 60℃, then the mixture is cooled to room temperature, and 0.01mol / L ammonia water is used to adjust the pH to 6, and then the mixture is aged at a temperature of 25℃ for 24h to obtain a sol;

[0095] The mass ratio of the Y source solution, the citric acid and the ammonia water is 10:2:0.2.

[0096] Comparative Example 1-2

[0097] The present comparative example provides a preparation process of a nickel-based corrosion-resistant alloy, specifically comprising the following steps:

[0098] Step 1: The nickel-based alloy components are smelted by a vacuum induction and electroslag remelting smelting process to obtain a nickel-based alloy blank;

[0099] In the vacuum induction smelting process, the nickel-based alloy components are taken out by mass percentage and loaded into a magnesium crucible, the vacuum degree is ≤10 -2 Pa, the temperature is increased to 1550℃ and kept for 45min by induction heating, and Ar gas is used for stirring and impurity removal; the slag system for electroslag remelting is composed of CaF2, Al2O3 and CaO with a mass ratio of 40:30:30, the electrode diameter is 150mm, the current density is 5A / cm 2 , the melting speed is 0.65kg / min, and the slag pool temperature is 1575℃, and the temperature is decreased to room temperature at a rate of 3.5℃ / min in the cooling stage;

[0100] The nickel-based alloy composition includes, in terms of mass percentage, Cr 22.5%, Mo 10%, Al 5.5%, Ta 1.5%, W 2.5%, Nb 1.15%, Re 1.5%, Ru 1.5%, La 0.07%, Hf 0.7%, C≤0.01%, Mn≤0.2%, and the balance of Ni;

[0101] Step 2: The nickel-based alloy blank is forged and rolled into a plate, and the plate is obtained by heat preservation at 1200°C for 1.1h, intermediate heat treatment at 840°C for 3h, and desensitization heat treatment at 675°C for 1.5h.

[0102] The forging and rolling specifically includes: first, the nickel-based alloy blank is heated and preserved at 1150°C for 4h, forged by multiple times, and a forging blank is obtained; then, the forging blank is heated to 1165°C and preserved for 2.9h, and the rolling is started at a temperature of≥1100°C, multiple passes of hot rolling are performed, the final rolling temperature is 875°C, and the total reduction is≥80%, so that the nickel-based corrosion-resistant alloy is prepared.

[0103] Comparative Examples 1-3

[0104] The present comparative example provides a preparation process of a nickel-based corrosion-resistant alloy, which specifically includes the following steps:

[0105] Step 1: The nickel-based alloy composition is smelted by a vacuum induction and electroslag remelting process to obtain a nickel-based alloy blank.

[0106] In the vacuum induction smelting, the nickel-based alloy composition is taken out by mass percentage and loaded into a magnesium crucible, the vacuum degree is≤10 -2 Pa, inducted to 1550°C for 45min, and impurities are removed by Ar gas stirring; the slag system of the electroslag remelting includes CaF2, Al2O3 and CaO in a mass ratio of 40:30:30, the electrode diameter is 150mm, the current density is 5A / cm 2 , the melting speed is 0.65kg / min, the slag pool temperature is 1575°C, and the cooling stage is reduced to room temperature at a rate of 3.5°C / min;

[0107] The nickel-based alloy composition includes, in terms of mass percentage, Cr 22.5%, Mo 10%, Al 5.5%, Ta 1.5%, W 2.5%, Nb 1.15%, Re 1.5%, Ru 1.5%, La 0.07%, Hf 0.7%, C≤0.01%, Mn≤0.2%, and the balance of Ni;

[0108] Step 2: The nickel-based alloy blank is forged and rolled into a plate, and the plate is obtained by heat preservation at 1200°C for 1.1h, intermediate heat treatment at 840°C for 3h, and desensitization heat treatment at 675°C for 1.5h.

[0109] The forging rolling specifically includes the following steps: first, the nickel-based alloy blank is heated at 1150 DEG C for 4 hours, forged for multiple times, the forging ratio is 4, and a forged blank is obtained; then, the forged blank is reheated to 1165 DEG C and kept for 2.9 hours, the rolling is started at a temperature of 1100 DEG C or above, the hot rolling is performed in multiple passes, the final rolling temperature is 875 DEG C, and the total reduction is 80% or above, so that the nickel-based corrosion-resistant alloy is prepared.

[0110] Comparative Examples 1-4

[0111] The present comparative example provides a preparation process of a nickel-based corrosion-resistant alloy, which specifically includes the following steps:

[0112] Step 1: the nickel-based alloy components are smelted by a vacuum induction and electroslag remelting smelting process, so that a nickel-based alloy blank is obtained;

[0113] In the vacuum induction smelting process, the nickel-based alloy components are taken out by mass percentage, put into a magnesium crucible, the vacuum degree is 10 -2 Pa or below, heated to 1550 DEG C and kept for 45 minutes, and impurities are removed by Ar gas stirring; the slag system of the electroslag remelting process is composed of CaF2, Al2O3 and CaO with a mass ratio of 40:30:30, the electrode diameter is 150 mm, the current density is 5 A / cm 2 , the melting speed is 0.65 kg / min, the slag pool temperature is 1575 DEG C, and the cooling stage is reduced to room temperature at a rate of 3.5 DEG C / min;

[0114] In the process, the nickel-based alloy components include Cr 22.5%, Mo 10%, Al 5.5%, Ta 1.5%, W 2.5%, Nb 1.15%, La 0.07%, Hf 0.7%, C≤0.01%, Mn≤0.2%, and the balance of Ni, by mass percentage;

[0115] Step 2: the nickel-based alloy blank is forged and rolled into a plate, kept at 1200 DEG C for 1.1 hours, intermediate heat treated at 840 DEG C for 3 hours, desensitization heat treated at 675 DEG C for 1.5 hours, and a nickel-based alloy plate is obtained.

[0116] The forging rolling specifically includes the following steps: first, the nickel-based alloy blank is heated at 1150 DEG C for 4 hours, forged for multiple times, the forging ratio is 4, and a forged blank is obtained; then, the forged blank is reheated to 1165 DEG C and kept for 2.9 hours, the rolling is started at a temperature of 1100 DEG C or above, the hot rolling is performed in multiple passes, the final rolling temperature is 875 DEG C, and the total reduction is 80% or above, so that the nickel-based corrosion-resistant alloy is prepared.

[0117] Comparative Examples 1-5

[0118] The present comparative example provides a preparation process of a nickel-based corrosion-resistant alloy, which specifically includes the following steps:

[0119] Step 1: a nickel-based alloy component is smelted by a vacuum induction and electroslag remelting process to obtain a nickel-based alloy blank;

[0120] In the vacuum induction smelting, the nickel-based alloy component is taken out by mass percentage and loaded into a magnesium crucible, the vacuum degree is ≤10 -2 Pa, inducted to 1550 DEG C and kept for 45 min, and impurities are removed by Ar gas stirring; the slag system for electroslag remelting is composed of CaF2, Al2O3 and CaO with a mass ratio of 40:30:30, the electrode diameter is 150 mm, the current density is 5 A / cm 2 , the melting speed is 0.65 kg / min, the slag pool temperature is 1575 DEG C, and the cooling stage is reduced to room temperature at a rate of 3.5 DEG C / min;

[0121] In the nickel-based alloy component, according to mass percentage, Cr is 22.5%, Mo is 10%, Al is 5.5%, Ta is 1.5%, W is 2.5%, Nb is 1.15%, Hf is 0.7%, C is ≤0.01%, Mn is ≤0.2%, and the balance is Ni;

[0122] Step 2: the nickel-based alloy blank is forged and rolled into a plate, is kept at 1200 DEG C for 1.1 h, is subjected to intermediate heat treatment at 840 DEG C for 3 h, is subjected to desensitization heat treatment at 675 DEG C for 1.5 h, and the nickel-based alloy plate is obtained;

[0123] In the forging and rolling, the nickel-based alloy blank is first heated at 1150 DEG C for 4 h, is forged for multiple times, the forging ratio is 4, the forged blank is obtained; the forged blank is reheated to 1165 DEG C and kept for 2.9 h, is rolled at a temperature ≥1100 DEG C, is hot rolled in multiple passes, the final rolling temperature is 875 DEG C, and the total reduction is ≥80%, and the nickel-based corrosion-resistant alloy is prepared.

[0124] In the examples and comparative examples, the cerium nitrate hexahydrate is from Shanghai Aladdin Bio-Chem Technology Co., Ltd., the CAS number is 10294-41-4; the yttrium nitrate hexahydrate is from Shanghai Aladdin Bio-Chem Technology Co., Ltd., the CAS number is 13494-98-9; the citric acid is from Hunan Dongting Citric Acid Chemical Co., Ltd., the CAS number is 77-92-9.

[0125] Performance test

[0126] The nickel-based corrosion-resistant alloys prepared from the nickel-based corrosion-resistant alloys of Example 2-1, Example 2-2, Example 2-3 and Comparative Examples 1-1 to 1-5 are selected as the test samples for hot corrosion test, and the specific process is as follows:

[0127] The sample to be tested was oxidized at 950℃ for 10h in a high-temperature box furnace, wherein the test temperature was 900℃ and the test duration was 100h; wherein the corrosion salt solution was composed of 75g / L Na2SO4, 25g / L NaCl and deionized water. One hot corrosion cycle included dropping 1mg / cm2 of the corrosion salt solution on the surface of the sample, placing the sample into a 900℃ high-temperature furnace after the surface solution was dried, taking out the sample after 10h, immersing the sample into boiling deionized water after it was cooled to room temperature, cleaning the sample twice to ensure that there was no residual corrosion salt film on the surface of the sample, and finally drying and weighing the sample. The next cycle of hot corrosion experiment was performed after the weighing was completed, and the process was repeated 3 times. The weight gain per unit area was calculated, and the specific test results are shown in Table 1. 2

[0128] Table 1

[0129]

[0130] From the test results in Table 1, it can be seen that the hot corrosion performance of the nickel-based corrosion-resistant alloy prepared in Example 2-1, Example 2-2 and Example 2-3 is better than that of Comparative Example 1-1 to Comparative Example 1-5, and the hot corrosion effect of Example 2-3 is the best, with the smallest weight change, which indicates that it has good stability and durability in a high-temperature corrosion environment. Compared with Example 2-1, Comparative Example 1-1 lacks Ce, which cannot form CeO2 in the surface coating of the nickel-based corrosion-resistant alloy, and the compactness of the coating is reduced, so the molten salt can easily penetrate into the substrate, resulting in faster corrosion in the early stage, and there is no interface synergistic effect of CeO2 and the substrate La / Hf, the bonding force between the oxidation film and the substrate is poor, and the hot corrosion resistance is reduced after 70h. Compared with Comparative Example 1-1, Comparative Example 1-2 forms a Cr2O3-Al2O3 oxidation film on the substrate itself, but there is no coating protection, so the hot corrosion resistance is reduced. Compared with Comparative Example 1-2, Comparative Example 1-3 lacks the anti-creep element Re in the substrate, which causes the decrease of the grain boundary strength of the substrate, the oxidation film is easy to crack along the grain boundary, the corrosion substances penetrate into the grain boundary, and the corrosion is accelerated, so the hot corrosion resistance is reduced. Compared with Comparative Example 1-3, Comparative Example 1-4 lacks the element Ru in the substrate, which causes the coarsening of the γ' phase at high temperature, and the decrease of the stability of the substrate structure and the corrosion resistance. Compared with Comparative Example 1-4, Comparative Example 1-5 lacks the interface strengthening element La in the substrate, which cannot be synergistically segregated at the grain boundary to reduce the grain boundary energy, improve the grain boundary strength and improve the adhesion of the oxidation film. Under the action of thermal stress, the oxidation film will accelerate the peeling, so the hot corrosion resistance is further reduced.

[0131] Although the embodiments of the present application have been shown and described, it should be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and any equivalent changes and improvements made within the scope of the present application should still fall within the scope of the patent coverage of the present application.​

Claims

1. A process for preparing a nickel-based corrosion-resistant alloy, characterized in that: The following steps are involved: Step (1) smelting the nickel-based alloy components by vacuum induction and electroslag remelting smelting process to obtain a nickel-based alloy billet; Step (2) forging and rolling the nickel-based alloy billet into a plate, performing a solid solution treatment, an intermediate heat treatment, and a desensitization heat treatment to obtain a nickel-based alloy plate; Step (3) pre-treating the nickel-based alloy plate to obtain a pre-treated nickel-based alloy plate; Step (4) spraying the sol on the surface of the pretreated nickel-based alloy plate to form a wet film; performing heat treatment under a nitrogen atmosphere, and cooling to room temperature with the furnace to obtain a nickel-based corrosion-resistant alloy; The nickel-based alloy comprises, by mass percentage, Cr20-25%, Mo9-11%, Al4.5-6.5%, Ta1-2%, W2-3%, Nb0.8-1.5%, Re1-2%, Ru1-2%, La0.05-0.1%, Hf0.5-1%, C≤0.01%, Mn≤0.2%, and the balance Ni; The preparation method of the sol comprises the following steps: The Ce source solution and the Y source solution are mixed, citric acid is added, stirred, heated, stirred, cooled, pH adjusted with ammonia water, aged, and a sol is obtained.

2. The process for preparing a nickel-based corrosion-resistant alloy according to claim 1, characterized in that: In the step (2), the specific process of forging and rolling is as follows: the first step is to perform a forging process, specifically, heating the nickel-based alloy billet at 1100-1200°C for 3.5-4.5 hours, adopting multi-fire forging, and a forging ratio of 4-5 to obtain a forging billet; the second step is to perform a rolling process, reheating the forging billet to 1150-1180°C and keeping it for 2.6-3.2 hours, adopting multi-pass hot rolling, controlling the final rolling temperature at 850-875°C, and the total reduction rate ≥80%, and finally rolling it into a plate.

3. The process for preparing a nickel-based corrosion-resistant alloy according to claim 1, wherein: In the step (2), the solution treatment conditions are: keeping the temperature at 1180-1220° C. for 1-1.2 hours.

4. The process for preparing a nickel-based corrosion-resistant alloy according to claim 1, wherein: In the step (2), the intermediate heat treatment condition is: keeping warm at a temperature of 780-900°C for 2-4 hours.

5. The process for preparing a nickel-based corrosion-resistant alloy according to claim 1, characterized in that: In the step (2), the desensitization heat treatment conditions are: desensitization heat treatment is carried out at 650-700°C for 1-2 hours.

6. The process for preparing a nickel-based corrosion-resistant alloy according to claim 1, characterized in that: In step (3), the method for preparing the pretreated nickel-based alloy plate comprises the following steps: The surface of the nickel-based alloy plate was coarsely ground with 200#, 400#, 600# and 800# SiC sandpaper in sequence and polished with a polishing machine until the surface roughness Ra ≤ 0.2 μm, washed with anhydrous ethanol solution, dried, washed with a 0.01 mol / L NaOH aqueous solution at 50°C, rinsed with deionized water, washed with a 0.01 mol / L nitric acid aqueous solution at 50°C for 5 minutes, rinsed with deionized water, and dried to obtain the pretreated nickel-based alloy plate.

7. The process for preparing a nickel-based corrosion-resistant alloy according to claim 1, characterized in that: In the step (4), the S content in the nickel-based corrosion-resistant alloy is ≤0.0001%, and the P content is ≤0.0001%.

8. The process for preparing a nickel-based corrosion-resistant alloy according to claim 1, characterized in that: In the step (4), the heat treatment conditions are as follows: room temperature as the initial temperature, heating to 130-150°C at a rate of 5°C / min and keeping warm for 0.4-0.6h; heating to 300-350°C at a rate of 2°C / min and keeping warm for 0.8-1.2h; heating to 620-650°C at a rate of 2°C / min and keeping warm for 1.5-2h.

9. The process for preparing a nickel-based corrosion-resistant alloy according to claim 1, characterized in that: In the step (4), the Ce source solution is prepared as follows: 8 g of cerium nitrate hexahydrate [Ce(NO3)3·6H2O] is dissolved in 25 mL of ethanol aqueous solution with a mass concentration of 30%, and stirred to obtain a Ce source solution; the Y source solution is prepared as follows: 1.2 g of yttrium nitrate hexahydrate [Y(NO3)3·6H2O] is dissolved in 10 mL of deionized water to obtain a Y source solution; wherein the mass ratio of the Ce source solution, the Y source solution, the citric acid and the ammonia water is (30-40):(10-15):(8-10):(2-6).

10. A nickel-based corrosion-resistant alloy, characterized in that: The nickel-based corrosion-resistant alloy is prepared by the preparation process of any one of claims 1 to 9.

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