Smelting process of high-carbon content superalloy ingots with dispersed carbide distribution

Abstract

This invention discloses a smelting process for high-carbon content superalloy ingots with dispersed carbide distribution. Specifically, the process involves: weighing nickel-based superalloy raw materials, including electrode C, metallic Cr, Co plates, Mo strips, Al beads, sponge Ti, NiB master alloy, and Ni plates; subjecting the nickel-based superalloy raw materials to vacuum induction melting to obtain a vacuum induction ingot; sawing the head of the vacuum induction ingot, polishing the surface, and then using it as an electroslag remelting electrode for remelting and refining to obtain an electroslag remelted ingot; and finally, vacuum arc remelting to obtain a high-carbon content superalloy ingot. In the vacuum arc remelting process of this invention, a larger remelting current is used, creating a narrower paste-like region, reducing the local cooling time of the alloy, and improving the fine dispersion of carbides.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature alloy smelting technology, specifically relating to the smelting process of high-carbon content high-temperature alloy ingots with dispersed carbide distribution. Background Technology

[0002] Carbides in high-temperature alloys play a dual role. On the one hand, carbides at grain boundaries can pin grain boundaries, inhibit grain growth, hinder grain migration and slip, and improve the deformation resistance of the matrix. On the other hand, high-melting-point carbides can precipitate prematurely and adhere to the dendrites or grain boundaries, which not only hinders the replenishment of liquid phase to shrinkage cavities during solidification, but also, due to the high hardness of carbides, makes the formed liquid film easily torn apart. Carbides in high-temperature alloys generally occur in blocky, mesh-like, banded, and granular forms. When the smelting process is unsuitable, carbides in the alloy may segregate or be distributed in a chain-like manner, making them crack initiation and propagation paths during the alloy's service life, severely reducing the alloy's mechanical properties.

[0003] Currently, the distribution control of carbides in high-temperature alloys is mainly achieved by modifying the homogenization annealing and forging deformation processes during forging. Chinese Patent (Application No.: 202310835823.5, Publication No.: CN117051341A, Publication Date: 2023-07-10) discloses a method for improving carbide distribution in Ni-Fe-based high-temperature alloys used in ultra-supercritical thermal power units. This method improves carbide distribution in Ni-Fe-based high-temperature alloy bars by optimizing the billet forging process, thereby increasing the grain size and microstructure uniformity of the billet. However, for primary carbides generated during the smelting of high-carbon content (C≥0.05wt.%) high-temperature alloys, these carbides will not dissolve during homogenization and will be directly inherited into the bars. Therefore, controlling the dispersed distribution of carbides in the ingot has become a crucial step in the preparation of high-carbon content high-temperature alloys. Summary of the Invention

[0004] The purpose of this invention is to provide a smelting process for high-carbon content high-temperature alloy ingots with dispersed carbide distribution, thereby improving the dispersion and uniformity of carbide distribution in the alloy ingots.

[0005] The technical solution adopted in this invention is a smelting process for high-carbon content high-temperature alloy ingots with dispersed carbide distribution, specifically implemented according to the following steps:

[0006] Step 1: Weigh out the nickel-based high-temperature alloy raw materials, including electrode C, metal Cr, Co plate, Mo strip, Al bead, sponge Ti, NiB master alloy and Ni plate;

[0007] Step 2: The nickel-based high-temperature alloy raw material from Step 1 is subjected to vacuum induction melting to obtain a vacuum induction ingot.

[0008] Step 3, Electroslag Remelting: The vacuum induction casting obtained in Step 2 is sawn off at the head, and after surface polishing, it is used as an electroslag remelting electrode for remelting and refining to obtain an electroslag remelting casting.

[0009] Step 4: Vacuum self-consumable remelting to finally obtain a high-carbon high-temperature alloy ingot.

[0010] The invention is further characterized in that,

[0011] In step 1, the raw material for the nickel-based superalloy contains the following components by weight percentage: electrode C: 0.06~0.12%, metallic Cr: 18.00~20.00%, Co plate: 10.00~12.00%, Mo strip: 9.00~10.50%, Al bead: 1.40~1.80%, sponge Ti: 3.00~3.50%, NiB master alloy: 0.003~0.010%, with the balance being Ni plate and unavoidable inclusions. The sum of the above components by weight percentage is 100%.

[0012] The gas content of metallic Cr is not less than 100 ppm; the gaseous element content of sponge Ti is not less than 80 ppm.

[0013] Step 2 specifically involves:

[0014] First, Ni plates, Co plates, and electrode C from the raw materials are added into a vacuum induction furnace. Vacuum is drawn and power is applied to increase the induction melting power, keeping it in the range of 1095~1150kW. Then, Mo strips and metallic Cr are added. After the temperature is raised to complete melting, the melting power is reduced to 850~1950kW, and the melt temperature is controlled between 1450~1500℃. After maintaining this temperature for 7~13 minutes, the refining stage begins. Sponge Ti, Al beads, and NiB master alloy are added sequentially, and the melting power is increased to 1250~1350kW. The refining temperature is maintained at 1510~1530℃. Electromagnetic stirring is maintained during the refining process for 5~10 minutes.

[0015] The refined molten steel is then poured into the mold. Argon gas is continuously introduced during the casting process, and the casting temperature is 1450~1470℃. After casting, the ingot is cooled in the mold chamber and removed after 55~65 minutes to obtain a vacuum induction ingot.

[0016] In step 3, during electroslag remelting, the electroslag selected includes the following components by mass percentage: 62~70% CaF2, 16~20% CaO, 12~16% Al2O3, and 4~6% CeO, with the sum of the mass percentages of the above components being 100%.

[0017] In step 3, before adding slag, the electroslag is baked at 490~510℃ for more than 2 hours; during the electroslag remelting process, the melting rate and slag swing are controlled. The melting rate during the stable melting stage is 220~240kg / h, and the slag swing is 0.2~0.4mohm; when the electrode weight is ≤100kg, the hot capping stage is entered. After the hot capping is completed, the furnace is cooled for 60 minutes before demolding to obtain the electroslag remelted ingot.

[0018] Step 4 specifically involves:

[0019] The head of the electroslag remelting ingot is sawn, with the sawing height being more than 50mm from the head end face. The surface is peeled off to a depth of 5-9mm. After peeling, the surface oil is wiped dry and the ingot is dried in an oven. The clean ingot after drying is used as a vacuum consumable remelting electrode. High current density melting is used in the vacuum consumable remelting process to ensure that the depth of the molten pool is within the range of 90-120mm. Droplet control is used during the melting process, and the melting rate is set to 3-15 droplets / s. When the electrode weight is ≤80kg, the hot capping stage is entered. After the hot capping is completed, the furnace is cooled for 50 minutes, and the high carbon content high temperature alloy ingot is demolded.

[0020] The current density is calculated using the following formula:

[0021]

[0022] In the formula, i Current density, in A / cm² 2 ; d The value is the electrode diameter, in mm.

[0023] The beneficial effects of this invention are:

[0024] (1) The smelting process of the present invention uses metallic Cr with a gas content of not less than 100 ppm and sponge Ti with a gas element content of not less than 80 ppm, so that there is enough N element in the alloy to combine with Ti and other elements at a lower Gibbs free energy to form compounds such as TiN. These compounds are dispersed and serve as nucleation centers for carbides, thereby making the distribution of carbides more dispersed.

[0025] (2) The smelting process of the present invention uses a pre-melted slag system with CeO, which further makes the alloy contain more CeO as a heterogeneous nucleation center for carbides, thereby improving the dispersion of carbide distribution.

[0026] (3) In the smelting process of the present invention, a larger remelting current is used in the vacuum self-consuming remelting process, which creates a narrower paste-like region, reduces the local cooling time of the alloy, and improves the fine dispersion of carbides. Attached Figure Description

[0027] Figure 1This is a simplified flow chart of the smelting process for high-carbon content high-temperature alloy ingots with dispersed carbide distribution according to the present invention.

[0028] Figure 2 It is a scan image of carbides dispersed in the ingot;

[0029] Figure 3 This is a scan of blocky carbides with nitride cores in an ingot (I);

[0030] Figure 4 This is a scan of blocky carbides with nitride cores in an ingot (II). Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] The present invention relates to a smelting process for high-carbon content high-temperature alloy ingots with dispersed carbide distribution, such as... Figure 1 As shown, please follow these steps:

[0034] Step 1: Weigh out the nickel-based high-temperature alloy raw materials;

[0035] The raw materials for nickel-based superalloys contain the following components by weight percentage: electrode C: 0.06~0.12%, metallic Cr: 18.00~20.00%, Co plate: 10.00~12.00%, Mo strip: 9.00~10.50%, Al bead: 1.40~1.80%, sponge Ti: 3.00~3.50%, NiB master alloy: 0.003~0.010%, with the balance being Ni plate and unavoidable inclusions. The sum of the above components by weight percentage is 100%.

[0036] The gas content of metallic Cr is not less than 100 ppm; the gaseous element content of sponge Ti is not less than 80 ppm.

[0037] Step 2, vacuum induction melting;

[0038] First, Ni plates, Co plates, and electrode C from the raw materials are added into a vacuum induction furnace. Vacuum is drawn and power is applied to increase the induction melting power, keeping it in the range of 1095~1150kW. Then, Mo strips and metallic Cr are added. After the temperature is raised to complete melting, the melting power is reduced to 850~1950kW, and the melt temperature is controlled between 1450~1500℃. After maintaining this temperature for 7~13 minutes, the refining stage begins. Sponge Ti, Al beads, and NiB master alloy are added sequentially, and the melting power is increased to 1250~1350kW. The refining temperature is maintained at 1510~1530℃. Electromagnetic stirring is maintained during the refining process for 5~10 minutes.

[0039] The refined molten steel is then poured into the mold. Argon gas is continuously introduced during the casting process. The casting temperature is 1450~1470℃. After casting, the ingot is cooled in the mold chamber and removed after 55~65 minutes to obtain a vacuum induction ingot with a weight of 2600~2800 kg.

[0040] Before casting, a sample bucket was used to take samples and conduct composition tests. The main components of the alloy were all within the composition control range, with the content of O element being 8ppm~15ppm and the content of N element being 40ppm~60ppm.

[0041] Step 3: Electroslag remelting;

[0042] The vacuum induction casting obtained in step 2 is sawn at the head, with the sawing height being greater than 80mm from the head end face. After surface polishing, it is used as an electroslag remelting electrode for remelting and refining.

[0043] When electroslag remelting, the electroslag selected includes the following components by mass percentage: 62~70% CaF2, 16~20% CaO, 12~16% Al2O3, and 4~6% CeO, with the sum of the mass percentages of the above components being 100%; before adding the slag, the electroslag is baked at 490~510℃ for more than 2 hours.

[0044] The slag quantity is 68 kg per 1000 kg alloy and 25 kg of pre-melted slag.

[0045] The melting rate and slag swing are controlled during the electroslag remelting process. The melting rate during the stable melting stage is 220~240 kg / h and the slag swing is 0.2~0.4 mohm. When the electrode weight is ≤100 kg, the hot capping stage is entered. After the hot capping is completed, the furnace is cooled for 60 min and then the ingot is demolded to obtain the electroslag remelted ingot.

[0046] Step 4: Vacuum consumable remelting;

[0047] The electroslag remelting ingot undergoes head sawing, with a sawing height greater than 50mm from the head end face. Surface peeling is performed to a depth of 5-9mm. After peeling, the surface is wiped dry with a scouring pad and then dried in an oven. The resulting clean ingot serves as the vacuum consumable remelting electrode. High current density melting is employed during vacuum consumable remelting to ensure a molten pool depth of 90-120mm, allowing for thorough stirring. This aims to narrow the width of the mushy zone, increase the local cooling time of the alloy, and promote the fine, dispersed distribution of carbides. Droplet control is used during melting, with a melting rate set at 3-15 droplets / s. When the electrode weight is ≤80kg, the hot capping stage begins. After hot capping, the ingot is furnace cooled for 50 minutes and then demolded to obtain a high-carbon content high-temperature alloy ingot.

[0048] The current density is calculated using the following formula:

[0049]

[0050] In the formula, i Current density, in A / cm² 2 ; d The value is the electrode diameter, in mm.

[0051] The present invention relates to a smelting process for high-carbon content high-temperature alloy ingots with dispersed carbide distribution, including raw material preparation, vacuum induction melting, electroslag remelting, and vacuum consumable remelting. This process fundamentally improves the dispersion and uniformity of carbide distribution in the alloy ingot, which will provide a good raw material basis for the dispersed carbide distribution in subsequent processed materials.

[0052] Example 2

[0053] Step 1, Ingredient Preparation. According to the composition requirements of nickel-based superalloys: C: 0.085%, metallic Cr: 19.50%, Co plate: 10.80%, Mo strip: 9.80%, Al briquettes: 1.65%, sponge Ti: 3.32%, NiB master alloy: 0.006%, with the balance being Ni and unavoidable inclusions. The sum of the mass percentages of the above components is 100%.

[0054] Step 2: Vacuum Induction Melting. During the charging phase, the raw materials are added in the following order: Ni plate, Co plate, and electrode C. A vacuum is drawn and the induction melting power is increased to 1100kW. Then, Mo strips and metallic Cr are added. After complete melting, the melting power is reduced to 1050kW, and the melt temperature is controlled at 1478℃. After maintaining this temperature for 8 minutes, the refining stage begins. Sponge Ti, Al beads, and NiB master alloy are added sequentially, increasing the melting power to 1250kW and maintaining the refining temperature at 1510℃. Electromagnetic stirring is maintained during refining for 5 minutes. The refined molten steel is then poured. Before casting, a sample is taken using a sample bucket, and composition testing is performed. All major alloy components are within the controlled range, with O content at 12 ppm and N content at 54 ppm. Argon gas is continuously supplied during casting, and the casting temperature is 1465℃. After casting, the ingot is cooled in the mold chamber and removed after 60 minutes. The ingot weighs 2600 kg.

[0055] Step 3: Electroslag Remelting. The vacuum induction casting obtained in Step 2 is sawn at the head, with a sawing height greater than 80mm from the head end face. After surface polishing, it is used as the electroslag remelting electrode for remelting and refining. The electroslag remelting electrode uses a mixture of 65% CaF2, 18% CaO, 12% Al2O3, and 5% CeO by mass percentage. Before adding the slag, the pre-melted slag is baked at 500℃ for at least 2 hours. The slag quantity is 68kg per 1000kg alloy (25kg of pre-melted slag). During the electroslag remelting process, melting rate and slag sway are controlled. The melting rate during the stable melting stage is 230kg / h, and the slag sway is 0.2mohm. When the electrode weight is ≤100kg, the hot sealing stage begins. After hot sealing, the electrode is demolded after furnace cooling for 60 minutes.

[0056] Step 4: Vacuum Arsenic Remelting. The electroslag remelting ingot undergoes head sawing, with a sawing height greater than 50mm from the head end face. Surface peeling is performed to a depth of 8mm. After surface cleaning, the resulting material is used as the vacuum arsenic remelting electrode, with an electrode diameter of 430mm. The vacuum arsenic remelting process uses 9.1A / cm². 2 The melting process involves automatically adjusting the position of the electrode rod using droplet control to regulate the remelting rate of the alloy. The droplet setting range is 7 drops / s. When the electrode weight is ≤80kg, the process enters the hot sealing stage. After hot sealing, the alloy ingot is demolded after 50 minutes of furnace cooling to obtain the alloy ingot.

[0057] Figure 2 The image shows a scan of the carbides in the ingot obtained by this method. It can be seen that the carbides are uniformly distributed in a diffuse manner. Figure 3 and Figure 4 These are scanning electron microscope (SEM) images of carbides with oxide and nitride cores in ingots obtained using this method. Figure 3 and Figure 4 It can be seen that during the alloying process, carbides are formed with nitrides and oxides as the core at a lower Gibbs free energy, resulting in a more uniform distribution of carbides.

[0058] Table 1 shows the O and N content and carbide distribution in the ingots smelted using this method. It can be seen that the carbides in the ingots obtained by this method are fine, with an average size of 7.6 μm, and the distance between the carbides is relatively large, reaching 20.9 μm.

[0059] Table 1. O and N content and carbide distribution in alloy ingots

[0060]

[0061] Example 3

[0062] Step 1, Ingredient Preparation. Electrode composition according to nickel-based superalloy requirements: C: 0.065%, metallic Cr: 19.75%, Co plate: 10.60%, Mo strip: 9.79%, Al bean: 1.60%, sponge Ti: 3.42%, NiB master alloy: 0.003%, balance being Ni plate and unavoidable inclusions. The sum of the mass percentages of the above components is 100%.

[0063] Step 2: Vacuum Induction Melting. During the charging phase, the raw materials are added in the following order: Ni plate, Co plate, and electrode C. A vacuum is drawn and the induction melting power is increased to 1100kW. Then, Mo strips and metallic Cr are added. After complete melting, the melting power is reduced to 1050kW, and the melt temperature is controlled at 1478℃. After maintaining this temperature for 8 minutes, the refining stage begins. Sponge Ti, Al beads, and NiB master alloy are added, and the melting power is increased to 1350kW. The refining temperature is maintained at 1530℃. Electromagnetic stirring is maintained during refining for 5 minutes. The refined molten steel is then poured. Before casting, a sample is taken using a sample bucket, and composition testing is performed. The main alloy components are all within the controlled range, with O content at 12ppm and N content at 54ppm. Argon gas is continuously supplied during casting, and the casting temperature is 1465℃. After casting, the ingot is cooled in the mold chamber and removed after 60 minutes. The ingot weighs 2600 kg.

[0064] The refined molten steel was then poured into the mold. Argon gas was continuously introduced during the casting process. The casting temperature was 1450~1470℃. After casting, the ingot was cooled in the mold chamber and removed after 55~65 minutes to obtain a vacuum induction ingot with a weight of 2800 kg.

[0065] Before casting, a sample bucket was used to take samples and conduct composition tests. The main components of the alloy were all within the composition control range, with the content of O element being 8ppm~15ppm and the content of N element being 40ppm~60ppm.

[0066] Step 3: Electroslag Remelting. The vacuum induction casting obtained in Step 2 is sawn at the head, with a sawing height greater than 80mm from the head end face. After surface polishing, it is used as the electroslag remelting electrode for remelting and refining. The electroslag remelting electrode uses a mixture of 65% CaF2, 18% CaO, 12% Al2O3, and 5% CeO by mass percentage. Before adding the slag, the pre-melted slag is baked at 500℃ for at least 2 hours. The slag quantity is 68kg per 1000kg alloy (25kg of pre-melted slag). During the electroslag remelting process, melting rate and slag sway are controlled. The melting rate during the stable melting stage is 230kg / h, and the slag sway is 0.2mohm. When the electrode weight is ≤100kg, the hot sealing stage begins. After hot sealing, the electrode is demolded after furnace cooling for 60 minutes.

[0067] Step 4: Vacuum Arsenic Remelting. The electroslag remelting ingot undergoes head sawing, with a sawing height greater than 50mm from the head end face. Surface peeling is performed to a depth of 8mm. After surface cleaning, the resulting material is used as the vacuum arsenic remelting electrode, with an electrode diameter of 430mm. The vacuum arsenic remelting process uses 9.1A / cm². 2 The melting process involves automatically adjusting the position of the electrode rod using droplet control to regulate the remelting rate of the alloy. The droplet setting range is 7 drops / s. When the electrode weight is ≤80kg, the process enters the hot sealing stage. After hot sealing, the alloy ingot is demolded after 50 minutes of furnace cooling to obtain the alloy ingot.

[0068] Table 2 shows the O and N content and carbide distribution in the ingots obtained by this method. As can be seen, consistent with Example 2, the carbides in the ingots obtained by this method are small with an average size of 7.7 μm and a large distance between them, reaching 24.9 μm.

[0069] Table 2. O and N content and carbide distribution in alloy ingots

[0070]

[0071] Comparative Example 1

[0072] A high-temperature alloy with the same nominal composition as that in Example 2 was prepared using a process of batching → vacuum induction melting → electroslag remelting → vacuum arc remelting. The method of this comparative example is basically the same as that of Example 2, except that degassed Cr and pure Ti blocks were used as raw materials. Table 3 shows the O and N content and carbide distribution in the ingots obtained by conventional melting methods.

[0073] Table 3. O and N content and carbide distribution in ingots prepared by conventional smelting methods.

[0074]

[0075] As can be seen, compared with Example 2, the carbide size in the ingot obtained by melting using conventional methods (i.e. without using metallic Cr with a gas content of not less than 100 ppm and sponge Ti with a gas element content of not less than 80 ppm) is comparable to that in Example 2, at 7.9 μm. However, the average distance between carbides is much smaller than that in Example 2, at only 14.9 μm. This indicates that the process of the present invention is effective in achieving the dispersed distribution of carbides and has promotional value.

[0076] Comparative Example 2

[0077] A high-temperature alloy with the same nominal composition as in Example 2 was prepared using a process of batching → vacuum induction melting → electroslag remelting → vacuum arc remelting. The method used in this comparative example is basically the same as in Example 2, except that the electroslag remelting used 65% CaF2, 18% CaO, and 17% Al2O3 by mass percentage. Table 4 shows the O and N content and carbide distribution in the ingots obtained from conventional melting.

[0078] Table 4. O and N content and carbide distribution in ingots prepared by conventional smelting methods.

[0079]

[0080] As can be seen, compared with Example 2, the carbide size in the ingot obtained by smelting using conventional methods (i.e., without using CeO pre-melted slag system) is comparable to that in Example 2, at 7.5 μm. However, the average distance between carbides is much smaller than that in Example 2, at only 14.9 μm. This indicates that the process of the present invention is effective in achieving the dispersed distribution of carbides and has promotional value.

[0081] Comparative Example 3

[0082] A high-temperature alloy with the same nominal composition as that in Example 2 was prepared using a process of batching → vacuum induction melting → electroslag remelting → vacuum arc remelting. The method in this comparative example is basically the same as that in Example 2, except that 7.8 A / cm² is used in the vacuum arc remelting process. 2 Smelting. Table 5 shows the O and N content and carbide distribution in the ingots obtained from smelting.

[0083] Table 5. O and N content and carbide distribution in ingots prepared by conventional smelting methods.

[0084]

[0085] As can be seen, compared with Example 2, the size of the carbides in the ingot obtained by melting using conventional methods (i.e. without using high current) is comparable to that in Example 2, which is 7.4 μm. However, the average distance between the carbides is much smaller than that in Example 2, which is only 12.9 μm. This shows that the process of the present invention is effective in achieving the dispersed distribution of carbides and has promotional value.

[0086] Example 4

[0087] The smelting process of the high-carbon content high-temperature alloy ingot with dispersed carbide distribution of the present invention is specifically implemented according to the following steps:

[0088] Step 1: Weigh out the nickel-based high-temperature alloy raw materials;

[0089] The raw materials for nickel-based superalloys contain the following components by weight percentage: electrode C: 0.10%, metallic Cr: 18.50%, Co plate: 11.10%, Mo strip: 9.50%, Al bead: 1.50%, sponge Ti: 3.25%, NiB master alloy: 0.009%, with the balance being Ni plate and unavoidable inclusions. The sum of the above components by weight percentage is 100%.

[0090] The gas content of metallic Cr is not less than 100 ppm; the gaseous element content of sponge Ti is not less than 80 ppm.

[0091] Step 2, vacuum induction melting;

[0092] First, Ni plates, Co plates, and electrode C from the raw materials are added into a vacuum induction furnace. Vacuum is drawn and power is applied to increase the induction melting power, which is maintained at 1150kW. Then, Mo strips and metallic Cr are added. After the temperature is raised to complete melting, the melting power is reduced to 1050kW, and the melt temperature is controlled at 1450℃. After maintaining this temperature for 7 minutes, the refining stage begins. Sponge Ti, Al beads, and NiB master alloy are added in sequence, and the melting power is increased to 1250kW. The refining temperature is maintained at 1510℃. Electromagnetic stirring is maintained during the refining process for 5 minutes.

[0093] The refined molten steel was then poured into the mold. Argon gas was continuously introduced during the casting process. The casting temperature was 1450℃. After casting, the ingot was cooled in the mold chamber and removed after 55 minutes to obtain a vacuum induction ingot with a weight of 2600 kg.

[0094] Before casting, a sample bucket was used to take samples and conduct composition tests. The main components of the alloy were all within the composition control range, with the O element content at 8 ppm and the N element content at 40 ppm.

[0095] Step 3: Electroslag remelting;

[0096] The vacuum induction casting obtained in step 2 is sawn at the head, with the sawing height being greater than 80mm from the head end face. After surface polishing, it is used as an electroslag remelting electrode for remelting and refining.

[0097] The melting rate and slag swing are controlled during the electroslag remelting process. The melting rate during the stable melting stage is 220 kg / h and the slag swing is 0.2 mohm. When the electrode weight is ≤100 kg, the hot capping stage is entered. After the hot capping is completed, the furnace is cooled for 60 min and then the ingot is demolded to obtain the electroslag remelted ingot.

[0098] Step 4: Vacuum consumable remelting;

[0099] The electroslag remelting ingot undergoes head sawing, with a sawing height greater than 50mm from the head end face. Surface peeling is performed to a depth of 5mm. After peeling, the surface is wiped dry with a scouring pad and then dried in an oven. The resulting clean ingot serves as the vacuum consumable remelting electrode. High current density melting is employed during vacuum consumable remelting to ensure a molten pool depth within 90mm, allowing for thorough stirring. This aims to narrow the width of the mushy zone, increase the local cooling time of the alloy, and promote the fine, dispersed distribution of carbides. Droplet control is used during melting, with a melting rate set at 3 droplets / s. The hot capping stage begins when the electrode weight is ≤80kg. After hot capping, the ingot is furnace cooled for 50 minutes and then demolded to obtain a high-carbon content high-temperature alloy ingot.

[0100] Example 5

[0101] The smelting process of the high-carbon content high-temperature alloy ingot with dispersed carbide distribution of the present invention is specifically implemented according to the following steps:

[0102] Step 1: Weigh out the nickel-based high-temperature alloy raw materials;

[0103] The raw materials for nickel-based superalloys contain the following components by weight percentage: electrode C: 0.12%, metallic Cr: 20.00%, Co plate: 12.00%, Mo strip: 10.50%, Al bead: 1.80%, sponge Ti: 3.50%, NiB master alloy: 0.010%, with the balance being Ni plate and unavoidable inclusions. The sum of the above components by weight percentage is 100%.

[0104] The gas content of metallic Cr is not less than 100 ppm; the gaseous element content of sponge Ti is not less than 80 ppm.

[0105] Step 2, vacuum induction melting;

[0106] First, Ni plate, Co plate and electrode C from the raw materials are added into the vacuum induction furnace. Vacuum is drawn and power is applied to increase the induction melting power to 1150kW. Then, Mo strip and metallic Cr are added. After the temperature is fully melted, the melting power is reduced to 1950kW and the melt temperature is controlled at 1500℃. After maintaining this temperature for 13 minutes, the refining stage begins. Sponge Ti, Al beads and NiB master alloy are added in sequence, and the melting power is increased to 1350kW. The refining temperature is maintained at 1530℃. Electromagnetic stirring is maintained during the refining process for 10 minutes.

[0107] The refined molten steel was then poured into the mold. Argon gas was continuously introduced during the casting process. The casting temperature was 1470℃. After casting, the ingot was cooled in the mold chamber and removed after 65 minutes to obtain a vacuum induction ingot with a weight of 2800 kg.

[0108] Before casting, a sample bucket was used to take samples and conduct composition tests. The main components of the alloy were all within the composition control range, with the O element content at 15 ppm and the N element content at 60 ppm.

[0109] Step 3: Electroslag remelting;

[0110] The vacuum induction casting obtained in step 2 is sawn at the head, with the sawing height being greater than 80mm from the head end face. After surface polishing, it is used as an electroslag remelting electrode for remelting and refining.

[0111] The melting rate and slag swing are controlled during the electroslag remelting process. The melting rate during the stable melting stage is 240 kg / h and the slag swing is 0.4 mohm. When the electrode weight is ≤100 kg, the hot capping stage is entered. After the hot capping is completed, the furnace is cooled for 60 min and then the ingot is demolded to obtain the electroslag remelted ingot.

[0112] Step 4: Vacuum consumable remelting;

[0113] The electroslag remelting ingot undergoes head sawing, with a sawing height greater than 50mm from the head end face. Surface peeling is performed to a depth of 9mm. After peeling, the surface is wiped dry with a scouring pad and then dried in an oven. The resulting clean ingot serves as the vacuum consumable remelting electrode. High current density melting is employed during vacuum consumable remelting to ensure a molten pool depth within 120mm, allowing for thorough stirring. This aims to narrow the width of the mushy zone, increase the local cooling time of the alloy, and promote the fine, dispersed distribution of carbides. Droplet control is used during melting, with a melting rate set at 15 droplets / s. The hot capping stage begins when the electrode weight is ≤80kg. After hot capping, the ingot is furnace cooled for 50 minutes and then demolded to obtain a high-carbon content high-temperature alloy ingot.

[0114] Example 6

[0115] The present invention relates to a melting process for dispersed carbide distribution in high-carbon high-temperature alloy ingots. This process involves incorporating high-gas-content metallic Cr and sponge titanium during the batching and vacuum induction melting stages, and controlling the temperature during the induction melting refining phase to obtain a high-gas-content master alloy. The electroslag remelting process uses an alkaline slag system containing 5 wt.% Ce to ensure sufficient oxygen content and heterogeneous nucleation sites in the electroslag ingot. Vacuum arc remelting employs high-current melting to create a larger molten pool depth and adequate stirring conditions, narrowing the width of the mushy region and reducing the local cooling time of the alloy. The high-temperature alloy ingots prepared using this method exhibit fine and dispersed carbides, which significantly improves the banded carbide structure defects during subsequent hot deformation of the alloy.

Claims

1. A melting process for a carbide-dispersed high carbon content high temperature alloy ingot, characterized by, The following steps are specifically implemented: Step 1, weigh the raw materials of the nickel-based superalloy, including the following components by weight percentage: 0.06~0.12% electrode C, 18.00~20.00% metal Cr, 10.00~12.00% Co plate, 9.00~10.50% Mo strip, 1.40~1.80% Al bean, 3.00~3.50% sponge Ti, 0.003~0.010% NiB intermediate alloy, and the balance being Ni plate and unavoidable inclusions, the sum of the above component mass percentages being 100%; the gas content of the metal Cr is not less than 100 ppm; the gas element in the sponge Ti is not less than 80 ppm; Step 2, vacuum induction melting of the nickel-based superalloy raw materials in step 1 to obtain a vacuum induction ingot; specifically: First, add the Ni plate, Co plate and electrode C in the raw materials into the vacuum induction furnace, vacuumize and power on to increase the induction melting power, keep the power in the range of 1095~1150kW, then add the Mo strip and metal Cr, heat to complete melting, then reduce the melting power to 850~1950kW, control the melt temperature between 1450~1500℃, keep for 7~13min, then enter the refining stage, add the sponge Ti, Al bean and NiB intermediate alloy in sequence, increase the melting power to 1250~1350kW, keep the refining temperature at 1510~1530℃, keep electromagnetic stirring during the refining process, stirring time 5~10min; then pour the refined steel liquid, keep argon continuously charged during the pouring process, pouring temperature 1450~1470℃, after pouring is completed, the ingot is cooled in the ingot mold chamber, keep for 55~65min before demolding, obtain the vacuum induction ingot; Step 3, electroslag remelting: saw cut the head of the vacuum induction ingot obtained in step 2, after surface polishing, use it as an electroslag remelting electrode for remelting and refining, obtain an electroslag remelted ingot; During electroslag remelting, an electroslag is selected to include the following components by mass percentage: 62~70% CaF2, 16~20% CaO, 12~16% Al2O3, 4~6% CeO, the sum of the above component mass percentages being 100%; Step 4, vacuum consumable remelting, finally obtain a high-carbon-content high-temperature alloy ingot; specifically: Saw cut the head of the electroslag remelted ingot, the saw cutting height is greater than 50mm from the head end surface, skin the surface, the skinning depth is 5~9mm, after skinning, wipe off the surface oil and dry in an oven, the dry and smooth ingot is used as a vacuum consumable remelting electrode, during vacuum consumable remelting, use large current density melting, ensure the melt pool depth in the range of 90~120mm, use droplet control during melting, set the melting speed to 3~15 droplets / s, when the electrode weight is ≤80kg, enter the hot sealing stage, after hot sealing is completed, cool the furnace for 50min, demold to obtain a high-carbon-content high-temperature alloy ingot.

2. The melting process of a carbide-diffused high carbon content high-temperature alloy ingot according to claim 1, characterized by, In step 3, before adding slag, the electroslag is baked at 490-510 DEG C for more than 2h; during the electroslag remelting process, the melting speed and slag swing are controlled, the melting speed in the stable melting stage is 220-240 kg / h, and the slag swing is 0.2-0.4 mohm; when the electrode weight is less than or equal to 100 kg, the hot sealing top stage is entered, and after the hot sealing top stage is finished, the furnace is cooled for 60 min, and then demolding is carried out, so that the electroslag remelted ingot is obtained.

3. The melting process of carbide-diffused high carbon content high temperature alloy ingot according to claim 1, characterized in that, The current density is calculated according to the following formula: wherein i is the current density in A / cm2 2 ; d is the electrode diameter in mm.

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