A kind of iron-chromium-nickel-aluminum high-temperature alloy material and application method thereof

Abstract

The present invention discloses an iron-chromium-nickel-aluminum superalloy material and its application method. The iron-chromium-nickel-aluminum superalloy material comprises specific mass contents of chromium, aluminum, nickel, manganese, tungsten, molybdenum, titanium, nitrogen, tantalum, and zirconium. The chromium, aluminum, and nickel content is such that the volume percentage of the NiAl precipitated phase at high temperatures is less than 3%. The iron-chromium-nickel-aluminum superalloy material exhibits excellent coking resistance, oxidation resistance, and high-temperature durability, significantly improving the operating efficiency and economic benefits of ethylene radiation furnaces.

Description

Technical Field

[0001] The present invention relates to the technical field of iron-chromium-nickel-aluminum high-temperature alloy materials, in particular to an iron-chromium-nickel-aluminum high-temperature alloy material which can be used as a furnace tube material for an ethylene radiation furnace. Background Art

[0002] Ethylene radiant furnaces are key equipment in ethylene production, converting feedstock into chemical products such as ethylene and propylene through high-temperature cracking (900-1200°C). However, during the cracking process, carbon and coke deposits on the inner walls of the furnace tubes cause coking, which reduces heat transfer efficiency, increases tube wall temperatures, and increases operating pressure. This increases energy consumption, accelerates material degradation, and poses safety risks. Modern ethylene plants typically have a coke cleaning cycle of 30-90 days, requiring production downtime, which directly impacts operational efficiency and profitability. Therefore, reducing coking rates, extending operating cycles, and minimizing downtime for coke cleaning are crucial for improving economic returns.

[0003] On the other hand, ethylene radiation furnaces have high requirements for furnace tube materials, which usually need to have the following characteristics: (1) high-temperature strength, which can withstand the high-temperature conditions of the cracking reaction and have excellent creep strength; (2) anti-coking performance, such as improving the inertness of the surface, that is, reducing the contact and reaction between carbon atoms and Fe and Ni metals at high temperatures; (3) corrosion resistance to cope with the corrosion and carburization of the furnace tube materials by the corrosive gases generated during the cracking process; (4) long service life, reducing downtime, and improving the reliability and stability of the device operation.

[0004] Currently, the surface chromium oxide layer of high-temperature alloy furnace tubes primarily composed of iron, chromium, and nickel (FeCrNi) becomes unstable at temperatures exceeding 900°C, leading to scale vaporization or decomposition, accelerating coking and carburization, and significantly shortening the tube's lifespan. Some existing technologies have improved upon this, such as the iron-chromium-nickel-aluminum high-temperature alloys proposed in patents US 8431072 and US 8815146, which add an alumina protective layer to enable furnace tubes to operate well at temperatures between 600°C and 900°C. However, these technologies cannot further meet the requirements for high-temperature environments between 900°C and 1200°C. Furthermore, the high-aluminum centrifugally cast high-temperature material proposed in patent EP0169119A1, while offering improved oxidation resistance through an alumina protective layer, still fails to fully meet actual requirements in terms of coking speed and high-temperature durability.

[0005] In summary, the existing ethylene radiation furnace tube materials still have insufficient anti-coking performance, anti-oxidation performance and high-temperature durability in high-temperature environments. It is urgent to develop a new material to solve the above problems and improve the operating efficiency and economic benefits of ethylene radiation furnaces. Summary of the Invention

[0006] In view of the defects of the prior art, the purpose of the present invention is to propose a new iron-chromium-nickel-aluminum high-temperature alloy material with significantly improved anti-coking performance, anti-oxidation performance and high-temperature durability, which can significantly improve the operating efficiency and economic benefits of ethylene radiation furnaces.

[0007] The technical solutions of the present invention are as follows:

[0008] An iron-chromium-nickel-aluminum high-temperature alloy material, comprising the following elements: carbon, manganese, silicon, chromium, nickel, aluminum, niobium, titanium, tungsten, iron, molybdenum, nitrogen, calcium, tantalum, zirconium, hafnium, yttrium and cerium, wherein the mass percentage of carbon element is 0.4-0.6wt%, the mass percentage of nickel element is 38-50wt%, the mass percentage of chromium element is 23.0-32.0wt%, the mass percentage of manganese element is less than 2wt%, the mass percentage of silicon element is 0.1-1.5wt%, the mass percentage of aluminum element is 3.0-5.0wt%, the mass percentage of niobium element is 0.5-1.5wt%, the mass percentage of tungsten element is 0.01-1wt%, the mass percentage of molybdenum element is less than 1wt%, the mass percentage of tungsten element is less than 0.0 ... The mass percentage of the element is 0.01-1wt%, the mass percentage of the titanium element is 0.05-0.2wt%, the mass percentage of the nitrogen element is 0.005-0.2wt%, the mass percentage of the calcium element is 0.001-0.5wt%, the mass percentage of the yttrium element is 0.001-0.5wt%, the mass percentage of the cerium element is 0.001-0.5wt%, the mass percentage of the tantalum element is 0.01-0.5wt%, the mass percentage of the zirconium element is 0.01-0.5wt%, and the mass percentage of the hafnium element is 0.001-0.5wt%, and the mass percentage of the chromium element, aluminum element, and nickel element satisfies the following calculation model: f The value of (x) is less than 3%:

[0009]

[0010] in, f (x) represents the volume percentage of NiAl precipitated phase in the material, b1 represents the overall scaling parameter, b2 represents the influence coefficient of chromium, b3 represents the influence coefficient of aluminum, b4 represents the influence coefficient of nickel, b5 is a constant term, and b6 represents the exponential attenuation factor of temperature effect, whose values are: b1=1.5419, b2=-0.5839, b3=3.4687, b4=-1.3242, b5=61.3191, b6=0.2286; X cr Indicates the mass percentage of chromium element, X Al Indicates the mass percentage of aluminum element, X Ni represents the mass percentage of nickel element, and T represents the absolute temperature (K) when the iron-chromium-nickel-aluminum high-temperature alloy material is used.

[0011] In the above scheme of the present invention:

[0012] Carbon plays an important role in high-temperature alloys. It enhances the high-temperature creep resistance of the material through carbide precipitation and also has a significant impact on the fluidity of molten steel.

[0013] Aluminum can form a dense aluminum oxide film in high-temperature alloy casting, improving the alloy's high-temperature resistance and anti-oxidation and anti-carburization properties. To ensure the sustainability and integrity of the aluminum oxide film, the aluminum content in the alloy is best maintained above 2%; if the aluminum content exceeds 7%, a large number of irregular, microscopic precipitates will appear in the alloy, affecting the alloy's grain structure and reducing the material's comprehensive mechanical properties. Therefore, preferably, the aluminum content should be in the range of 3-5%.

[0014] Chromium can also form an oxide film or form a composite oxide film with aluminum oxide that has excellent high-temperature oxidation resistance, effectively protecting the metal matrix from oxidation and corrosion. At the same time, in the process of carbide precipitation, chromium is a carbide precipitate M. 23 C6 is the primary component of the alloy, enhancing its high-temperature strength and creep resistance. The inventors unexpectedly discovered that if the chromium content exceeds 35%, and nickel and aluminum are present in the alloy, the unfavorable Sigma phase may form, reducing the material's mechanical properties. Therefore, the preferred chromium content is maintained between 23% and 32% to ensure a good balance between oxidizability, corrosion resistance, and mechanical properties.

[0015] Nickel is a key element in casting high-temperature alloys. Sufficient nickel stabilizes austenite (the face-centered cubic (CFC) structure), imparting high-temperature toughness and plasticity to the alloy. It also promotes carbide precipitation, enhancing the alloy's durability and corrosion resistance. Furthermore, nickel serves as the primary catalyst in the coking process, and excessive nickel content can accelerate the process.

[0016] The inventors unexpectedly discovered that when the nickel content exceeds 50%, in a high-temperature olefin environment, although the alloy surface is covered with an aluminum oxide film, the surface coking rate is significantly accelerated. Therefore, controlling the nickel content below 50% can effectively slow the coking rate in a cracking environment and reduce raw material costs. At the same time, increasing the nickel content helps to inhibit the precipitation of Sigma phase, and its content should not be less than 35%. Therefore, maintaining its content between 38-50% can improve the high-temperature performance of the material.

[0017] Silicon plays a role in high-temperature alloys, including deoxidizing molten steel, improving fluidity, and enhancing the stability of the oxide film through the formation of silicon oxide, thereby enhancing the alloy's oxidation resistance. However, excessive silicon content can reduce the material's deformation properties at high temperatures and affect the alloy's overall plasticity. Therefore, the optimal silicon content should be controlled within the range of 0.1-1.5wt%.

[0018] The role of manganese in high-temperature alloys includes deoxidation and controlling the sulfur (S) content, thereby improving the purity of the material. However, excessive manganese content will have an adverse effect on the creep properties of the material and reduce the alloy's high-temperature durability. Therefore, controlling it below 2% can ensure the optimal performance of the alloy.

[0019] The role of rare earth elements such as hafnium, yttrium, and cerium in high-temperature alloys includes improving the stability of the oxide scale and enhancing the bonding strength between the oxide scale and the base material interface, thereby improving the long-term service performance of the material in high-temperature environments. The inventors unexpectedly discovered that controlling their content within the range of 0.001-0.5% can ensure the material's optimal high-temperature resistance.

[0020] Tungsten can enhance the alloy's long-term strength and improve its high-temperature stability at high temperatures (approximately 1100°C) through solid solution strengthening. However, the inventors unexpectedly discovered that excessive tungsten content can lead to the precipitation of laves and sigma particles. The growth of these precipitates can affect the material's long-term properties and plasticity, interfere with the diffusion of aluminum (Al), and reduce the long-term stability of the oxide film. Therefore, the tungsten content needs to be controlled between 0.01% and 1% to ensure optimal alloy performance.

[0021] Molybdenum can improve the high-temperature durability of the alloy through solid solution strengthening, and enhance the stability and durability of the material in high-temperature environments. The inventors unexpectedly discovered that controlling its content within the range of 0.01-1% can ensure the optimal high-temperature performance of the alloy.

[0022] Niobium, which precipitates primarily as carbide (MC), significantly enhances the material's durability and has a significant impact on its high-temperature creep properties. It is a key element in improving the alloy's high-temperature resistance. The inventors unexpectedly discovered that controlling the niobium content within the 0.5-1.5% range ensures excellent durability and high-temperature creep resistance.

[0023] The addition of titanium can not only enhance the creep resistance of the alloy, but also improve the fatigue resistance and crack resistance of the material, thereby extending its service life. 23C6 has good thermal stability and can effectively inhibit grain coarsening and softening. The inventors unexpectedly discovered that controlling the titanium content within the range of 0.05-0.2% ensures the material has optimal high-temperature mechanical properties.

[0024] Nitrogen can significantly enhance the material's high-temperature strength and durability by precipitating nitrides in the alloy, improving its deformation resistance and fatigue resistance. However, excessive nitrogen content can adversely affect the material's plasticity, leading to a decrease in the alloy's high-temperature stability. The inventors unexpectedly discovered that controlling the nitrogen content within the range of 0.005-0.2% can ensure that the material maintains good creep properties while improving its high-temperature strength.

[0025] Calcium, a strong desulfurizer and deoxidizer, effectively reduces the sulfur and oxygen content in molten steel, significantly improving the alloy's purity and enhancing the material's corrosion resistance and durability in high-temperature environments. The inventors unexpectedly discovered that controlling the calcium content within the range of 0.001-0.5% ensures optimal desulfurization and deoxidation, while also improving the material's overall performance.

[0026] Tantalum, in solid solution in high-temperature alloys, significantly increases lattice distortion, resulting in a strong solid-solution strengthening effect. This strengthening mechanism effectively improves the alloy's high-temperature strength and creep resistance, enabling it to maintain good mechanical stability under extreme service conditions. Furthermore, tantalum has a strong affinity for carbon, promoting the formation of dispersion-strengthened carbides (such as TaC). These high-melting-point carbide particles, uniformly distributed in the matrix, effectively pin dislocation motion, hindering grain boundary slip and grain growth, thereby significantly enhancing the material's high-temperature durability and hardness.

[0027] Zirconium can form stable ZrC carbides with carbon in high-temperature alloys. These dispersed carbides can effectively hinder dislocation movement, thereby significantly improving the high-temperature hardness and creep resistance of the material. In addition, zirconium can also promote the formation of other strengthening phases (such as M 23 The stable precipitation of C6 and MC carbides further enhances the alloy's precipitation strengthening effect, improving its high-temperature strength and durability. Furthermore, during the alloy smelting process, zirconium reacts with impurity elements such as oxygen and sulfur to form stable oxides or sulfides, effectively reducing the content of non-metallic inclusions and thus improving the material's purity. This not only improves the alloy's casting properties and makes its structure more uniform, but also enhances the stability of its mechanical properties, providing more reliable protection for high-temperature service.

[0028] On this basis, the inventor unexpectedly found that in the above element composition, especially the co-addition of Al, Cr, and Ni, compared with the traditional precipitate M 23C6 and MC phases also form NiAl and BCC phases. NiAl is a detrimental phase that forms microcracks at the boundary between the alloy matrix and the NiAl phase. These microcracks further expand with increasing NiAl content, increasing the material's macrocrack tendency. Simultaneously, as the NiAl content increases, BCC phases gradually appear at NiAl grain boundaries, further exacerbating the material's cracking tendency. Therefore, to improve the material's high-temperature creep performance, it is necessary to control the NiAl volume fraction within a relatively low range, which will also simultaneously suppress the appearance of BCC phases. The inventors unexpectedly discovered that within a specific element range, the computational model can effectively predict the volume fraction of NiAl precipitates at high temperatures, such as 900-1200°C, using Al, Cr, Ni content, and certain measured parameters. This avoids the cracking tendency caused by NiAl precipitates and thus improves the high-temperature creep resistance of the furnace tube.

[0029] The inventors also unexpectedly discovered that the calculation model is applicable to high-temperature alloys with an Al content of 3-5%, a Cr content of 23-32%, a Ni content of 38-50%, and an application temperature of 900-1200°C.

[0030] It should be noted that BCC, another precipitated phase that degrades the material's high-temperature performance, forms at the grain boundaries between the NiAl phase and the parent material matrix. This BCC phase only appears when the NiAl phase has a high volume fraction. Therefore, the present invention effectively suppresses the formation of BCC by controlling the NiAl phase content to a low range.

[0031] The inventor unexpectedly discovered that when f When the value of (x) is less than 3%, the material can have good high-temperature creep and excellent comprehensive mechanical properties in the high-temperature range of 900-1200℃, meeting the current engineering equipment design requirements.

[0032] Preferably, the inventors unexpectedly discovered that when f When the value of (x) is less than 1%, the material can show high temperature and long-lasting performance in the high temperature range of 900-1200℃. The high temperature test fracture time under the same conditions is much shorter than that of the f (x) = 3% further improved by 3 to 6 times.

[0033] According to some preferred embodiments of the present invention, the iron-chromium-nickel-aluminum high-temperature alloy material contains impurity elements with a mass percentage of less than 400 ppm and the balance iron, and the impurity elements include sulfur with a mass percentage of less than 100 ppm and phosphorus with a mass percentage of less than 300 ppm.

[0034] In the preferred embodiment described above, phosphorus is an impurity element that concentrates at grain boundaries, significantly reducing the alloy's plasticity and toughness, increasing its brittleness and potentially leading to brittle fracture, particularly at high or low temperatures. Furthermore, the presence of phosphorus promotes grain boundary weakening, reducing the material's creep properties and endurance strength, thereby impacting the long-term serviceability of the high-temperature alloy. During welding, phosphorus also increases susceptibility to hot cracking, impacting weld quality and joint reliability.

[0035] Sulfur exists primarily in the alloy as sulfides, which easily form low-melting-point compounds such as Ni3S2. These compounds precipitate along grain boundaries, causing grain boundary cracking during high-temperature service, thereby reducing endurance strength and creep properties. Furthermore, sulfide inclusions reduce the alloy's metallurgical purity, affecting casting and mechanical stability.

[0036] According to some preferred embodiments of the present invention, in the iron-chromium-nickel-aluminum high-temperature alloy material, the mass percentage of carbon element is 0.45-0.55wt%, the mass percentage of manganese element is less than 0.5wt%, the mass percentage of silicon element is 0.5-0.9wt%, the mass percentage of chromium element is 24-31wt%, the mass percentage of nickel element is 44-47wt%, the mass percentage of aluminum element is 3.5-4.5wt%, the mass percentage of niobium element is 0.7-0.9wt%, the mass percentage of titanium element is 0.1-0.15wt%, the mass percentage of tungsten element is 0.5-0.8wt%, and the mass percentage of tantalum element is 100-150wt%. The invention relates to a novel aluminum sintered steel having a molybdenum element and a zirconium element content of 0.1-0.2wt%, a zirconium element content of 0.05-0.1wt%, a yttrium element content of 0.05-0.1wt%, a cerium element content of 0.05-0.1wt%, a molybdenum element content of 0.05-0.5wt%, a nitrogen element content of 0.05-0.1wt%, a hafnium element content of 0.05-0.1wt%, a calcium element content of 0.01-0.2wt% and iron as the remainder excluding impurities, wherein the mass percentage content of the impurities is less than 130ppm, including less than 30ppm of sulfur and less than 100ppm of phosphorus.

[0037] The inventors unexpectedly discovered that under high-temperature working conditions of the iron-chromium-nickel-aluminum high-temperature alloy material obtained within the above range, the coking rate on the furnace tube surface is lower than that of iron-chromium-nickel, while its high-temperature endurance performance is more than double that of general iron-chromium-nickel high-temperature alloy materials.

[0038] The present invention further discloses a method for applying the above-mentioned iron-chromium-nickel-aluminum high-temperature alloy material to the furnace tube of an ethylene radiation furnace.

[0039] For example, in some preferred embodiments, the application includes: forming the iron-chromium-nickel-aluminum high-temperature alloy material into an ethylene radiation furnace tube and performing a pre-oxidation treatment.

[0040] The inventors unexpectedly discovered that when the iron-chromium-nickel-aluminum high-temperature alloy material is pretreated in an optimized oxygen partial pressure environment, the stability of the oxide scale can be enhanced, the quality of the oxide film can be effectively improved, and the service life of the furnace tube in a high-temperature and high-oxygen environment can be extended.

[0041] Preferably, the pre-oxidation treatment is carried out at a temperature of 900° C. for a period of 12-36 hours.

[0042] Preferably, the oxygen partial pressure of the pre-oxidation treatment is 10 -27 bar below.

[0043] With respect to the above preferred embodiments, the inventors unexpectedly discovered that by creating a high temperature and low oxygen partial pressure environment, the oxidation order of the surface of the Fe-Cr-Ni-Al high temperature alloy material can be changed. In order to preferentially form a complete and dense aluminum oxide film, the oxidation order of the surface of the Fe-Cr-Ni-Al high temperature alloy material can be changed by creating a high temperature and low oxygen partial pressure environment. -27 An oxidation reaction is carried out in a bar environment to obtain a stable aluminum oxide film, and after it is stabilized, a chromium oxide film is formed.

[0044] With respect to the above preferred embodiments, the inventors unexpectedly discovered that within the Al content range of the present invention, the oxygen partial pressure has a significant effect on the thermal stability and fatigue resistance of the oxide scale. -27 When the temperature is below bar, the thermal stability of the oxide scale is significantly poor, which can easily lead to the destruction of the oxide film and accelerated oxidation of the material.

[0045] The present invention has the following beneficial effects:

[0046] (1) The present invention provides a new FeCrNiAl-based alloy that can replace the traditional FeCrNi-based alloy, which can significantly reduce the coking rate of furnace tubes while maintaining excellent high-temperature endurance performance (equivalent to or better than the current mainstream European standard EN 1.4889 high-temperature alloy);

[0047] (2) The present invention solves the problem of high nickel content in existing alloys leading to catalytic coking on the surface of metal oxide scale by regulating the nickel content in the alloy, and controls the coking rate on the surface of the material at a very low level;

[0048] (3) The present invention suppresses the precipitation of NiAl phase and BCC phase by controlling the composition ratio of Cr, Ni and Al, thereby solving the problem of the existing alloy causing the degradation of furnace tube durability due to the precipitation of NiAl phase, and improving and stabilizing the durability of the material;

[0049] (4) The present invention further solves the local coking problem of existing alloys in high-temperature applications through the pre-oxidation process, provides anti-coking performance of furnace tube oxide scale, and improves the anti-coking performance of furnace tubes. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a statistical analysis chart of the Ni content of samples 1, 2, 3, 7, 8, and 9 obtained in Example 1 and the weight change after the first coking process.

[0051] Figure 2 This is a statistical analysis chart of the weight changes of samples 1, 2, 4, and 5 obtained in Example 1 after the 50th coking process and the oxygen partial pressure during their pre-oxidation.

[0052] Figure 3 This is a comparison chart of the NiAl phase volume fractions of samples 1, 2, 3, 4, and 5 calculated using the JMatPro software and the F model obtained in Example 2.

[0053] Figure 4 The LMP curve comparison diagram of samples 1, 2, 3, and 6 obtained in Example 3 and the existing material ZG50Ni45Cr35NbM is shown.

[0054] Figure 5 This is the backscattered electron mode image of the sampling sample obtained in Example 4 under a scanning electron microscope.

[0055] Figure 6 for Figure 5 Select the element spectrum of region 1.

[0056] Figure 7 for Figure 5 Select the element spectrum of area 2.

[0057] Figure 8 for Figure 5 Select the element spectrum of area 3. DETAILED DESCRIPTION

[0058] The technical solutions of the present invention will be further described below in conjunction with the embodiments of the present invention. The embodiments described below are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0059] Example 1

[0060] Eleven high-temperature alloy material samples, namely samples 1-11, were prepared according to the compositions shown in Table 1-2 below:

[0061] Table 1 Elemental composition of samples 1-5

[0062]

[0063] Table 2 Elemental composition of samples 6-11

[0064]

[0065] The samples were all square metal samples with a size of 3 cm×3 cm×3 mm, and the surface roughness was controlled to be less than 3.2 μm by machining.

[0066] All samples were pre-oxidized at 900°C for 24 hours. The pre-oxidation atmosphere and oxygen partial pressure of different samples were as follows:

[0067] The pre-oxidation atmosphere of samples 1, 3, 6, 7, 8, 9, 10, and 11 was 10 vol% water vapor and 90 vol% inert gas argon, with an oxygen partial pressure of approximately 10 -27 bar;

[0068] The pre-oxidation atmosphere of sample 5 is 10 vol% dry air and 90 vol% water vapor, and the oxygen partial pressure is about 10 -10 bar;

[0069] The pre-oxidation atmosphere of sample 4 is 100 vol% water vapor, and the oxygen partial pressure is about 10 -20 bar;

[0070] The pre-oxidation atmosphere of sample 2 was 2 vol% water vapor and 97 vol% inert gas argon, with an oxygen partial pressure of about 10 -30 bar.

[0071] Thermogravimetric experiments were performed on the pre-oxidized samples to evaluate the coking condition by the increase in sample mass. The thermogravimetric experiments were performed using a high-temperature tubular heating furnace. The experimental steps included:

[0072] (1) Heating stage, including:

[0073] Coking process: at 1150 ° C, introduce 30 vol% water vapor and 70% vol% C2H6 atmosphere for 2 hours;

[0074] Decoking process: at 950℃, introduce 50%vol steam and 50%vol air atmosphere for 50 minutes;

[0075] (2) Cooling and weighing stage: After each coking process and each decoking process, inert gas is introduced and the temperature is gradually lowered to room temperature, and then the sample is taken out and weighed.

[0076] The Ni content of samples with different Ni contents (samples 1, 2, 3, 7, 8, 9, 10, and 11) and their weight changes after pre-oxidation and the first coking process were statistically analyzed. The results are shown in the attached figure. Figure 1 As shown. Comparing samples 1, 2, 3, 7, 8, and 9, it can be seen that although a dense aluminum oxide film is formed on the surface of the material after pre-oxidation, the growth of MC and M23C6 precipitates near the surface may cause the material matrix to be exposed to a high-temperature environment with high carbon density, resulting in varying degrees of coking and weight gain. Sample 2 was pre-oxidized at a lower oxygen partial pressure than sample 1, and its surface aluminum oxide film density should be higher than that of sample 1. However, the carbon deposition rate of sample 2 is still higher than that of sample 1, indicating that the nickel content is the main factor affecting the carbon deposition rate. The results also show that when the Ni content exceeds 50%, the coking rate of the material increases three times. Therefore, controlling the Ni content below 50% can significantly reduce the coking rate. Comparing samples 1, 10, and 11, it can be seen that the weight change of the aluminum-added sample 1 after the first coking process is significantly different from that of the traditional FeCrNi products 10 and 11. The Ni content is not the main reason here. The main reason is that the aluminum oxide film on the surface of the aluminum-added sample 1 is more stable at 1150°C than the traditional chromium oxide film, and the latter undergoes gasification or decomposition reactions at high temperatures, causing the Fe and Ni in the base material to be exposed to an atmosphere with high solubility of C atoms, thereby accelerating the surface carbon deposition rate.

[0077] Furthermore, samples 1, 2, 4, and 5, which had undergone different pre-oxidation processes and all had Ni contents less than 50%, were subjected to the same 50 coking and 49 decoking processes. The weight changes of the samples after the 50th coking process were statistically analyzed with the oxygen partial pressure during the pre-oxidation. The results are shown in the attached figure. Figure 2 As shown in the figure, the Al and Cr contents of the above samples are similar, so it can be considered that the oxide scale components and compositions of the samples are the same. The only difference is the oxygen partial pressure of the pre-oxidation. Figure 2 , the oxygen partial pressure of samples 1 and 2 in pre-oxidation is less than 10 -27 Bar, the coking rate after 50 coking processes is the same and is only slightly higher than that of the first coking process. The pre-oxidation oxygen partial pressures of samples 4 and 5 are 10 -20 and 10 -10 Bar, as the oxygen partial pressure increases, the coking speed of the material increases. Therefore, in order to ensure the high temperature performance of the material in an environment greater than 1000℃, the oxygen partial pressure of the pre-oxidation is 10 -27 It is best in a low-oxygen, high-temperature environment below bar.

[0078] Example 2

[0079] The volume fraction of NiAl precipitated phase in samples 1, 2, 3, 4 and 5 at 900° C. in the steady state in Example 1 was calculated using JMatPro software and the F model.

[0080] JMatPro is a professional materials simulation software widely used to calculate the thermophysical properties and phase transformation behavior of materials. In precipitate phase research, JMatPro uses thermodynamic calculations to predict the type, volume fraction, and stability of precipitates in alloy materials under different temperatures, compositions, and heat treatment conditions. In this example, the compositions of samples 1, 2, 3, 4, and 5 were entered into JMatPro, and a nickel-based superalloy database was selected. The volume percentage of the NiAl precipitate phase in these samples at a steady state of 900°C was obtained.

[0081] The F model is calculated as follows:

[0082]

[0083] in, f (x) represents the volume percentage of NiAl phase, b1 represents the overall scaling parameter, b2 represents the influence coefficient of chromium, b3 represents the influence coefficient of aluminum, b4 represents the influence coefficient of nickel, b5 is a constant term, and b6 represents the exponential attenuation factor of temperature effect, whose values are: b1=1.5419, b2=-0.5839, b3=3.4687, b4=-1.3242, b5=61.3191, b6=0.2286; X cr Indicates the mass content percentage of chromium element, X Al Indicates the percentage of aluminum content by mass, X Ni It represents the percentage of nickel content by mass, and T represents the absolute temperature (K) of the material when it is used at high temperature. Here, the absolute temperature corresponding to 900°C is 1173.15K.

[0084] The calculation results of JMatPro are that the volume fractions of NiAl phase of samples 1, 2, 3, 4 and 5 at 900℃ are 1.19, 3.13, 4.24, 0.13 and 1.19 respectively. The comparison with the calculation results of F model is shown in the attached figure. Figure 3 As shown, it can be seen that the F model is accurate.

[0085] Example 3

[0086] Five sets of high-temperature durability tests were performed on samples 1, 2, 3, and 6 in Example 1. The experimental process was as follows: at 950°C, tensile forces of 35 MPa, 30 MPa, and 25 MPa were applied to each sample, respectively; at 1150°C, the sample completed two high-temperature durability tests under a tensile force of 12 MPa, and its fracture time under different pressures was recorded.

[0087] The volume percentages of NiAl phase of samples 1, 2, 3, and 6 calculated according to the F model at 950°C are 1.04, 3.13, 4.24, and 2.14, respectively.

[0088] The experimental results are shown in Table 3 below:

[0089] Table 3 High temperature endurance test results

[0090]

[0091] The above experimental results are compared with the LMP curve of the existing ZG50Ni45Cr35NbM (corresponding to the European standard En 1.4889) heat-resistant and corrosion-resistant alloy. The results are shown in the attached figure. Figure 4 As shown in the figure, it can be seen that in the temperature range of 950-1150℃, when the volume percentage of the NiAl phase of the sample is higher than 3.13%, the high-temperature rupture performance of the sample is lower than the minimum value of the LMP curve of the ZG50Ni45Cr35NbM alloy, and as this value increases, the high-temperature performance of the material gradually decreases. When the percentage of NiAl precipitation phase in the material is less than or equal to 1%, the high-temperature performance of the material is equivalent to or slightly higher than that of ZG50Ni45Cr35NbM.

[0092] At the same time, the results also show that due to the addition of 5% W, sample 6 has a calculated volume percentage of NiAl phase of 2.14%, but its endurance performance is far lower than the minimum value of ZG50Ni45Cr35NbM. The main reason is that there is not only 2.14% volume fraction of NiAl in the base material, but also the sigma phase and Laves phase generated by the addition of W element, which reduces the high-temperature endurance performance.

[0093] Example 4

[0094] After sample 1 was fractured at 950℃ and 35MPa tension for 890 hours, the sample was sampled. The sampling position was the support end of the sample, that is, the part that was only exposed to high temperature but not subjected to tension, and the microstructure was observed. The results are shown in the attached figure. Figure 5-8 As shown, Figure 5 This is the image of the backscattered electron mode of the scanning electron microscope. Figures 6 to 8 These are the element energy spectra of selected area 1, selected area 2 and selected area 3 respectively. Figure 6 and Figure 7 Corresponding to M 23 Energy spectra of C6 precipitated phase (M represents a certain metal element, mainly Cr element here) and MC (M is mainly Nb element here) precipitated phase, Figure 8is the energy spectrum of the material matrix. It can be seen that, as predicted by the F model calculation results, no NiAl phase and BCC phase are found in the microstructure of sample 1, and the material has good high-temperature endurance performance.

[0095] It should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the technical solutions of the present invention. Any modifications to the technical solutions described in the aforementioned embodiments, or equivalent replacements of technical features made by persons of ordinary skill in the art that fall within the spirit and principles of the present invention, shall be included within the scope of protection of the present invention.

Claims

1. An iron-chromium-nickel-aluminum high-temperature alloy material, characterized in that: It includes the following elements: Carbon, manganese, silicon, chromium, nickel, aluminum, niobium, titanium, tungsten, iron, molybdenum, nitrogen, calcium, tantalum, zirconium, hafnium, yttrium and cerium, wherein the mass percentage of carbon element is 0.4-0.6wt%, the mass percentage of nickel element is 38-50wt%, the mass percentage of chromium element is 23.0-32.0wt%, the mass percentage of manganese element is less than 2wt%, the mass percentage of silicon element is 0.1-1.5wt%, the mass percentage of aluminum element is 3.0-5.0wt%, the mass percentage of niobium element is 0.5-1.5wt%, the mass percentage of tungsten element is 0.01-1wt%, and the mass percentage of molybdenum element is 0.01 -1wt%, the mass percentage of titanium is 0.05-0.2wt%, the mass percentage of nitrogen is 0.005-0.2wt%, the mass percentage of calcium is 0.001-0.5wt%, the mass percentage of yttrium is 0.001-0.5wt%, the mass percentage of cerium is 0.001-0.5wt%, the mass percentage of tantalum is 0.01-0.5wt%, the mass percentage of zirconium is 0.01-0.5wt%, the mass percentage of hafnium is 0.001-0.5wt%, and the mass percentages of chromium, aluminum, and nickel satisfy the following calculation model: f The value of (x) is less than 3%: ； in, f (x) represents the volume percentage of NiAl precipitated phase in the material, b1 represents the overall scaling parameter, b2 represents the influence coefficient of chromium, b3 represents the influence coefficient of aluminum, b4 represents the influence coefficient of nickel, b5 is a constant term, and b6 represents the exponential attenuation factor of temperature effect, whose values are: b1=1.5419, b2=-0.5839, b3=3.4687, b4=-1.3242, b5=61.3191, b6=0.2286; X cr Indicates the mass percentage of chromium element, X Al Indicates the mass percentage of aluminum element, X Ni represents the mass percentage of nickel element, and T represents the absolute temperature when the iron-chromium-nickel-aluminum high-temperature alloy material is used.

2. The iron-chromium-nickel-aluminum high-temperature alloy material according to claim 1, characterized in that: The mass percentages of chromium, aluminum and nickel satisfy the calculation model. f The value of (x) is less than 1%.

3. The iron-chromium-nickel-aluminum high-temperature alloy material according to claim 1, characterized in that It contains impurity elements with a mass percentage content of less than 400 ppm and the balance of iron, wherein the impurity elements include sulfur with a mass percentage content of less than 100 ppm and phosphorus with a mass percentage content of less than 300 ppm.

4. The iron-chromium-nickel-aluminum high-temperature alloy material according to claim 1, characterized in that in, The mass percentage of carbon element is 0.45-0.55wt%, the mass percentage of manganese element is less than 0.5wt%, the mass percentage of silicon element is 0.5-0.9wt%, the mass percentage of chromium element is 24-31wt%, the mass percentage of nickel element is 44-47wt%, the mass percentage of aluminum element is 3.5-4.5wt%, the mass percentage of niobium element is 0.7-0.9wt%, the mass percentage of titanium element is 0.1-0.15wt%, the mass percentage of tungsten element is 0.5-0.8wt%, and the mass percentage of tantalum element is 0.1-0.2wt%. The mass percentage of zirconium element is 0.05-0.1wt%, the mass percentage of yttrium element is 0.05-0.1wt%, the mass percentage of cerium element is 0.05-0.1wt%, the mass percentage of molybdenum element is 0.05-0.5wt%, the mass percentage of nitrogen element is 0.05-0.1wt%, the mass percentage of hafnium element is 0.05-0.1wt%, the mass percentage of calcium element is 0.01-0.2wt%, and the remainder is iron excluding impurities, the mass percentage of the impurities is less than 130ppm, including less than 30ppm of sulfur element and less than 100ppm of phosphorus element.

5. The iron-chromium-nickel-aluminum high-temperature alloy material according to claim 1, characterized in that in, The mass percentage of carbon is 0.42wt%, the mass percentage of manganese is 0.1wt%, the mass percentage of silicon is 0.41wt%, the mass percentage of chromium is 25wt%, the mass percentage of nickel is 45.1wt%, the mass percentage of aluminum is 4.0wt%, the mass percentage of niobium is 0.9wt%, the mass percentage of titanium is 0.11wt%, the mass percentage of tungsten is 0.8wt%, and the mass percentage of tantalum is 0. .14wt%, the mass percentage content of zirconium element is 0.06wt%, the mass percentage content of yttrium element is 0.01wt%, the mass percentage content of cerium element is 0.009wt%, the mass percentage content of molybdenum element is 0.3wt%, the mass percentage content of nitrogen element is 0.11wt%, the mass percentage content of hafnium element is 0.012wt%, the mass percentage content of calcium element is 0.012wt% and the remainder is iron excluding impurities, wherein the impurities include 21ppm of sulfur element and 200ppm of phosphorus element.

6. Use of the iron-chromium-nickel-aluminum high-temperature alloy material according to any one of claims 1 to 5 in an ethylene radiation furnace tube.

7. The use according to claim 6, comprising: The iron-chromium-nickel-aluminum high-temperature alloy material is formed into an ethylene radiation furnace tube and subjected to a pre-oxidation treatment.

8. The use according to claim 7, characterized in that The temperature of the pre-oxidation treatment is 900° C., and the time is 12-36 hours.

9. The use according to claim 7, characterized in that The oxygen partial pressure of the pre-oxidation is 10 -27 bar below.

Images