A repairing method for prolonging the service life of a crucible for vacuum induction melting of high-temperature alloy

Abstract

The application relates to the field of high-temperature vacuum smelting, and discloses a repairing method for prolonging the service life of a crucible for high-temperature alloy vacuum induction smelting, which has the technical scheme as follows: cooling the crucible; removing the contaminants on the inner wall of the crucible; cleaning the alloy blocks in the cracks or local falling pits; preparing a first mixture by mixing alumina powder and a water glass type high-temperature adhesive, and preparing a second mixture by mixing a phosphorus-free refractory mortar and a water glass type high-temperature adhesive; first, infiltrating and filling the first mixture into the defect area, and then, infiltrating and coating the second mixture on the periphery of the inner wall of the crucible, and then, carrying out segmented baking. The application can improve the bonding stability of the repairing material and the inner wall of the crucible, reduce the cracking, bulging and falling risks of the repairing layer, prolong the service life of the crucible, and improve the safety of the vacuum induction smelting.

Description

Technical Field

[0001] This invention relates to the field of high-temperature vacuum melting, and more specifically to a repair method for improving the lifespan of crucibles used in high-temperature alloy vacuum induction melting. Background Technology

[0002] Vacuum induction melting is a commonly used melting method in the preparation of high-temperature alloys. During the melting process, the crucible, as a key component that supports the molten metal and participates in the isolation of the high-temperature smelting environment, needs to withstand the thermal shock, physical erosion, and chemical corrosion of the high-temperature molten metal over a long period of time. For alumina crucibles, after multiple consecutive melting cycles, problems such as alloy slag adhesion, furnace charge accumulation, microcracks, localized detachment, pitting, or uneven wall thickness are prone to appear on the inner wall of the crucible.

[0003] If a crucible is used directly after it has cracks or partial damage, the molten metal may further penetrate the crucible wall along the cracks or damage during the smelting process. In severe cases, this can cause a furnace penetration accident, affecting the safety of the vacuum induction melting process. On the other hand, crucible manufacturing and replacement take a long time and require significant labor and material costs. If a crucible is scrapped entirely when it has only minor damage, it will reduce production efficiency and increase production costs. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a repair method for improving the service life of crucibles used in vacuum induction melting of high-temperature alloys. This method overcomes the above-mentioned defects in the existing technology and can fill and repair the defective areas after cracks and / or local detachment pits appear on the inner wall of the crucible, and form an overall repair and protective layer on the inner wall of the crucible, thereby improving the service life of the crucible, reducing the frequency of crucible replacement, and improving the safety of the vacuum induction melting process.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys includes: S1. Cool the refractory crucible to be repaired to room temperature; S2. Remove the contaminants from the inner wall of the refractory crucible to expose the local defects on the inner wall of the crucible. S3. Clean the foreign objects from the local defective areas, including cracks and localized detachment pits; S4. Mix the refractory powder with the first high-temperature binder to obtain a first mixture for filling the local defect area; S5. Mix the phosphorus-free refractory mortar with the second high-temperature adhesive to obtain a second mixture for covering the inner wall of the crucible. S6. Apply a third high-temperature adhesive to the interior and surrounding area of ​​the local defect to impregnate the local defect area; S7. Fill the local defect area with the first mixture and compact and level the filled first mixture. S8. Apply a fourth high-temperature adhesive to the inner wall of the refractory crucible to wet the inner wall of the crucible. S9. The second mixture is coated around the inner wall of the refractory crucible to form an inner wall repair and protection layer; S10. The refractory crucible coated with the first mixture and the second mixture is heated and baked in stages to solidify the first mixture and the second mixture and bond them to the inner wall of the crucible.

[0006] In this invention, preferably, the refractory powder is alumina powder, the first high-temperature binder is SP50 water glass, and the mass ratio of the alumina powder to the SP50 water glass is set between 1.5:1 and 2.5:1.

[0007] In this invention, preferably, the purity of the alumina powder is not less than 99.9%.

[0008] In this invention, preferably, the second high-temperature adhesive is SP38 water glass, and the mass ratio of the phosphorus-free refractory mortar to the SP38 water glass is 3:1.

[0009] In this invention, preferably, the segmented heating and baking includes sequentially performing the following steps: holding at 60°C to 100°C for 45 min to 60 min; Heat to 200℃~300℃ and hold for 15min~30min; Continue heating to 500℃~600℃ and hold for 20min~40min.

[0010] In this invention, preferably, in steps S6 and S8, the third high-temperature adhesive and the fourth high-temperature adhesive are SP38 type water glass.

[0011] In this invention, preferably, in step S7, after the first mixture is filled, the repair site is flush with the inner wall of the surrounding crucible, or the height of the repair site above the inner wall of the surrounding crucible does not exceed 2mm.

[0012] In this invention, preferably, in step S9, the thickness of the inner wall repair protective layer is 2mm to 3mm.

[0013] In this invention, preferably, when the previous furnace casting is completed before the repair operation, the molten alloy in the crucible is poured out and the crucible is kept tilted to reduce the residual protrusions of alloy slag and furnace charge adhering to the inner wall of the crucible.

[0014] In this invention, preferably, the refractory crucible to be repaired is an alumina crucible.

[0015] The beneficial effects of this invention are: By first cleaning the alloy blocks from cracks and / or localized detachment pits, and then impregnating the defective area with a water glass-based high-temperature adhesive, the contact sufficiency and bonding stability between the first mixture and the inner wall of the defective area can be improved. By using alumina powder and the first water glass-based high-temperature adhesive to form the first mixture, and then using this mixture to fill cracks and / or localized detachment pits, the defective area can be substantially filled, reducing the risk of molten metal continuing to intrude along the cracks or pits. By using phosphorus-free refractory mortar and the second water glass-based high-temperature adhesive to form the second mixture, and then coating the inner wall of the crucible with the second mixture, a continuous repair and protective layer can be formed on the inner wall of the crucible, reducing the risk of erosion and detachment of the localized repair area during subsequent melting. Using phosphorus-free refractory mortar reduces the possibility of introducing phosphorus into the high-temperature alloy melt, which is beneficial for maintaining the stability of the high-temperature alloy composition. By using a segmented baking method to gradually dehydrate, solidify, and bond the repair material to the inner wall of the crucible, the risk of bulging, cracking, or detachment of the repair layer caused by a single high-temperature baking process can be reduced. The crucible repaired using the method of this invention can continue to complete multiple melting cycles, extending the service life of the crucible, reducing the cost of crucible manufacturing and replacement, and improving the safety of the vacuum induction metallurgy process. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the operation process of the present invention; Detailed Implementation The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0019] This embodiment provides a repair method for alumina crucibles used in vacuum induction melting of high-temperature alloys. This method is applicable to alumina crucibles used in vacuum induction melting processes, and is particularly suitable for alumina crucibles whose inner walls have developed cracks, localized spalling pits, or partial damage after continuous melting of nickel-based superalloys, cobalt-based superalloys, and / or iron-based mold steels. Figure 1 As shown, the repair method includes the following steps.

[0020] S1. Cooling of the melting crucible.

[0021] Cool the alumina crucible to be repaired until the temperature of the inner wall of the crucible does not exceed 60°C. Specifically, for crucibles that have just been melted, they need to be cooled naturally until the temperature of the inner wall of the crucible does not exceed 60°C before proceeding with subsequent cleaning and repair operations. This can reduce the risk of the repair material losing water too quickly, uneven coating, or reduced adhesion performance under high temperature conditions.

[0022] S2. Cleaning contaminants from the inner wall of the crucible.

[0023] Use a steel chisel, angle grinder, or other cleaning tools to remove alloy slag, adhering furnace charge, and / or other contaminants from the inner wall of the crucible, ensuring the inner wall is free of noticeable protruding contaminants and exposing the area to be repaired. Avoid striking the inner wall of the crucible with force during cleaning to minimize the possibility of secondary damage.

[0024] In a preferred embodiment, when the previous furnace casting is completed before repair, the molten alloy in the crucible is poured out as much as possible, and the crucible is kept at a certain angle before or during cooling so that the residual molten alloy, slag and adhering furnace charge can collect towards the pouring side or the lower side, which is beneficial for subsequent cleaning.

[0025] S3. Clean foreign objects from cracks or damaged areas on the inner wall of the crucible.

[0026] Inspect the inner wall of the crucible for cracks, localized flaking pits, and / or other damage. If alloy lumps or other foreign objects are found inside the cracks, pits, or damaged areas, clean them using tongs, a steel chisel, or other tools. If no lumpy residue remains inside the crack, the foreign object removal is considered complete.

[0027] S4. Prepare the first mixture.

[0028] Alumina powder is mixed with a first water glass-based high-temperature adhesive to obtain a first mixture. The first mixture is used to fill and repair cracks and / or localized detachment pits.

[0029] Preferably, the alumina powder has a purity of not less than 99.9%, thereby reducing the possibility of introducing impurity elements into the high-temperature alloy melt using the furnace repair material. The first water glass-based high-temperature binder is preferably SP50 water glass, and the mass ratio of alumina powder to SP50 water glass is preferably 2:1. Using this ratio, the first mixture possesses workability, heat resistance, and anti-detachment properties, and can effectively fill cracks and localized detachment pits.

[0030] S5. Prepare the second mixture.

[0031] A second mixture is obtained by mixing phosphorus-free refractory mortar with a second water glass-based high-temperature adhesive. This second mixture is used to form an inner wall repair and protective layer around the crucible.

[0032] Preferably, the second water glass-based high-temperature adhesive is SP38 water glass, and the mass ratio of phosphorus-free refractory mortar to SP38 water glass is 3:1. Using phosphorus-free refractory mortar can reduce the influence of phosphorus on the composition of high-temperature alloys. When the above ratio is used, the second mixture has suitable humidity and adhesion for coating, which is beneficial for forming a continuous and relatively uniform repair and protective layer on the inner wall of the crucible.

[0033] S6. Apply high-temperature adhesive to the inside and around cracks or damage on the inner wall of the crucible.

[0034] Using a curved-nose bottle, brush, or other coating tool, apply a high-temperature adhesive of water glass to the inside of the crack, the inside of the localized flaking pit, and the surrounding area, ensuring the surface of the area to be repaired is wetted. Preferably, the high-temperature adhesive of water glass used in this step is SP38 type water glass. By impregnating the area before filling with the first mixture, the bonding strength between the first mixture and the defective area can be improved.

[0035] S7. Repair the damaged area.

[0036] The first mixture is filled into the cracks and / or localized detachment pits, and then compacted and leveled using a scraper or other leveling tool. After filling, the repair area should be flush with the inner wall of the surrounding crucible, or its height above the inner wall of the surrounding crucible should not exceed 2 mm. By controlling the height of the repair area, the risk of the repair material falling off due to the erosion of localized protrusions by the molten metal during subsequent melting processes can be reduced.

[0037] S8. High-temperature adhesive is applied to the inner wall of the crucible.

[0038] Using a brush or other coating tool, evenly apply a water glass-based high-temperature adhesive to the inner wall of the crucible, ensuring the inner wall is thoroughly wetted. Preferably, the water glass-based high-temperature adhesive used in this step is SP38 type water glass. This step is used to improve the bonding stability between the second mixture and the inner wall of the crucible.

[0039] S9. Repair the inner wall of the crucible around its perimeter.

[0040] The second mixture is evenly coated around the inner wall of the crucible to form an inner wall repair and protective layer. Preferably, the thickness of the inner wall repair and protective layer is controlled to be 2mm to 3mm. Too thin a layer will reduce the overall protective effect; too thick a layer may increase the risk of bulging, cracking, or falling off during baking or subsequent melting.

[0041] S10, Crucible baking.

[0042] Graphite electrodes are placed inside the crucible, and the crucible is baked in sections. The section baking includes: holding at 60℃~100℃ for 45min~60min; raising the temperature to 200℃~300℃ and holding for 15min~30min; and continuing to raise the temperature to 500℃~600℃ and holding for 20min~40min.

[0043] Preferably, the segmented baking includes a first holding stage, a second holding stage, and a third holding stage performed sequentially. The first holding stage is at 80℃~85℃ for 50 minutes, the second holding stage is at 200℃~220℃ for 20 minutes, and the third holding stage is at 560℃~570℃ for 30 minutes. By gradually increasing and holding the temperature through the above temperature gradient, the first and second mixtures can be gradually dehydrated, solidified, and bonded to the inner wall of the crucible, reducing the risk of cracking, bulging, or peeling of the repair layer.

[0044] Example 1: The object to be repaired is an alumina crucible with a charge of 500 kg that was used for 16 consecutive heats of GH4169 alloy.

[0045] S1. Pass cooling water or natural cooling into the crucible after melting to cool it to room temperature. The measured temperature of the inner wall of the crucible is 42℃.

[0046] S2. Use a steel chisel or angle grinder to clean the alloy slag and adhering furnace charge around the inner wall of the crucible, so that there are no obvious protruding contaminants on the inner wall of the crucible.

[0047] S3. Upon inspection, an alloy block was found at the crack and removed using fire tongs. Cracks were present around the crucible, but no other forms of damage were found. The cracks were located 8 cm below the crucible's pouring spout. One crack was 11-12 cm long with an average depth of 0.8 cm, while the other three cracks were 6-7 cm long with an average depth of 0.6 cm.

[0048] S4. Mix alumina powder with a purity of not less than 99.9% with SP50 water glass at a mass ratio of 2:1 to form the first mixture.

[0049] S5. Mix the phosphorus-free refractory mortar and SP38 water glass evenly at a mass ratio of 3:1 to prepare the second mixture.

[0050] S6. Use a curved bottle and a brush to apply SP38 water glass to the inside and around the crack to wet the surface.

[0051] S7. Use the first mixture to fill the cracks, and use a scraper to compact and smooth the first mixture.

[0052] S8. Use a brush to evenly apply SP38 water glass to the inner wall of the crucible, so that the inner wall of the crucible is wetted.

[0053] S9. Use the second mixture to evenly coat the inner wall of the crucible, with the coating thickness controlled between 2mm and 3mm.

[0054] S10. The crucible is baked in sections, specifically at 80℃ for 50 minutes, 200℃ for 20 minutes, and 560℃ for 30 minutes, with the temperature increasing and holding sequentially according to the temperature gradient.

[0055] After repair, the crucible was used for eight consecutive furnaces without any detachment of the repair material. It was later scrapped due to cracks appearing on the surface of the repair material. The crucible was used a total of 24 times, an increase of 6 times compared to the previous average of 18 times, representing a lifespan improvement of approximately 33%.

[0056] Example 2: The object to be repaired is an alumina crucible with a charge of 350 kg that has been used for 17 consecutive heats of GH3230 alloy.

[0057] S1. Pass cooling water or allow natural cooling through the crucible after melting to cool it to room temperature. The measured temperature of the inner wall of the crucible is 58℃.

[0058] S2. Use a steel chisel or angle grinder to clean the alloy slag and adhering furnace charge from the inner wall of the crucible. Due to the rare earth elements in the GH3230 alloy and the use of recycled materials, there is a lot of slag on the crucible wall, and after cleaning, there are many cracks and pits on the inner wall surface of the crucible.

[0059] S3. Upon inspection, alloy blocks were found at the cracks and removed using tongs; alloy blocks in the dents were pried out using a steel chisel. The cracks were located 5cm below the crucible's pouring spout. One crack was 7cm-8cm long with an average depth of 0.9cm, while the other two cracks were 11cm-12cm long with an average depth of 0.6cm. The detached parts were located in the lower middle part of the crucible, covering an area of ​​approximately 40cm², and consisted of three locations scattered around the inner wall of the crucible, with an average detachment depth of 0.3cm.

[0060] S4. Mix alumina powder with a purity of not less than 99.9% with SP50 water glass at a mass ratio of 2:1 to form the first mixture.

[0061] S5. Mix the phosphorus-free refractory mortar and SP38 water glass evenly at a mass ratio of 3:1 to prepare the second mixture.

[0062] S6. Using a curved bottle and a brush, apply SP38 water glass to the inside and around the crack, the inside and around the pit, to wet the surface.

[0063] S7. Use the first mixture to fill the cracks and pits, and use a scraper to compact and smooth the first mixture.

[0064] S8. Use a brush to evenly apply SP38 water glass to the inner wall of the crucible, so that the inner wall of the crucible is wetted.

[0065] S9. Use the second mixture to evenly coat the inner wall of the crucible, with the coating thickness controlled between 2mm and 3mm.

[0066] S10. The crucible is baked in sections, specifically at 85℃ for 50 minutes, 220℃ for 20 minutes, and 570℃ for 30 minutes, with the temperature increasing and holding sequentially according to the temperature gradient.

[0067] After repair, the crucible was used for eight consecutive furnaces without any detachment of the repair material. It was later scrapped due to cracks appearing on the surface of the repair material. The crucible was used a total of 25 times, an increase of 7 times compared to the previous average of 18 times, representing a lifespan improvement of approximately 38%.

[0068] Example 3: This embodiment provides a repair method for an alumina crucible used in vacuum induction melting of high-temperature alloys. The repair object is an alumina crucible with a charge of 350 kg used in the continuous production of GH3230 alloy for 16 heats.

[0069] S1. Cooling the melting crucible: Pass cooling water or allow it to cool naturally through the crucible after melting to bring it to room temperature. In this embodiment, the temperature of the inner wall of the crucible is 58°C.

[0070] S2. Cleaning of contaminants on the inner wall of the crucible: Use a steel rod or angle grinder to clean the alloy slag and adhering furnace charge around the inner wall of the crucible. Due to the rare earth elements in the GH3230 alloy and the use of recycled materials, there was a lot of slag on the crucible wall, and after cleaning, there were several cracks on the surface of the inner wall of the crucible.

[0071] S3. Cleaning foreign objects from cracks or damaged areas on the inner wall of the crucible: If alloy blocks are found inside the cracks, remove them using tongs; if alloy blocks are found in the pits, pry them out with a steel chisel. The cracks are located 12cm below the crucible's pouring spout. One crack is 6cm-7cm long with an average depth of 0.6cm, and the other three cracks are 8cm-9cm long with an average depth of 0.5cm.

[0072] S4. Prepare the mixture of alumina and high-temperature binder: Mix alumina powder and SP50 water glass evenly at a mass ratio of 1.5:1 to prepare the first mixture.

[0073] S5. Prepare the mixture of refractory mortar and high-temperature adhesive: Mix the phosphorus-free refractory mortar and SP38 water glass evenly at a mass ratio of 3:1 to prepare the second mixture.

[0074] S6. Applying high-temperature adhesive to the inside and around cracks or damage on the inner wall of the crucible: Use a curved bottle and a brush to apply SP38 water glass to the inside and around the crack, so that the inside and around the crack are wetted.

[0075] S7. Repairing damaged areas: Use the first mixture to fill cracks and pits, and use a scraper to compact and smooth the first mixture.

[0076] S8. High-temperature adhesive coating around the inner wall of the crucible: Use a brush to evenly apply SP38 water glass around the inner wall of the crucible, so that the inner wall of the crucible is wetted.

[0077] S9. Repairing the inner wall of the crucible: Apply the second mixture evenly to the inner wall of the crucible, with the thickness controlled between 2mm and 3mm.

[0078] S10. Crucible baking: Heat and hold the crucible in sequence according to the temperature gradient, specifically 85℃ for 50 minutes, 220℃ for 20 minutes, and 570℃ for 30 minutes.

[0079] After repair, the crucible was used for four consecutive furnaces without any detachment from the repair material. The crucible was scrapped after cracks appeared on the surface of the repair material. In total, the crucible was used 20 times, an increase of 2 furnaces compared to the previous average of 18 furnaces, representing an improvement of approximately 11%.

[0080] Example 4: This embodiment provides a repair method for an alumina crucible used in vacuum induction melting of high-temperature alloys. The repair object is an alumina crucible with a charge of 350 kg used in the continuous production of GH4169 alloy for 16 heats.

[0081] S1. Cooling the melting crucible: Pass cooling water or allow it to cool naturally through the crucible after melting to bring it to room temperature. In this embodiment, the temperature of the inner wall of the crucible is 58°C.

[0082] S2. Cleaning of contaminants on the inner wall of the crucible: Use a steel rod or angle grinder to clean the alloy slag and adhering furnace charge around the inner wall of the crucible. After cleaning, some cracks and a few pits remain on the inner wall of the crucible.

[0083] S3. Cleaning foreign objects from cracks or damaged areas on the inner wall of the crucible: If alloy blocks are present in the cracks, remove them using tongs; if alloy blocks are present in the pits, pry them out with a steel chisel. The crack is located 4cm below the crucible's pouring spout. One crack is 10cm-11cm long with an average depth of 0.8cm, while the other two cracks are 8cm-9cm long with an average depth of 0.4cm. The detached area is located in the lower middle part of the crucible, with an area of ​​approximately 60cm². 2 There was one location, with an average detachment depth of 0.5cm.

[0084] S4. Prepare the mixture of alumina and high-temperature binder: Mix alumina powder and SP50 water glass evenly at a mass ratio of 2.5:1 to prepare the first mixture.

[0085] S5. Prepare the mixture of refractory mortar and high-temperature adhesive: Mix the phosphorus-free refractory mortar and SP38 water glass evenly at a mass ratio of 3:1 to prepare the second mixture.

[0086] S6. Apply high-temperature adhesive to the inside and around cracks or damage on the inner wall of the crucible: Use a curved bottle and brush to apply SP38 water glass to the inside and around the cracks, the inside and around the pits, and to wet the surface.

[0087] S7. Repairing damaged areas: Use the first mixture to fill cracks and pits, and use a scraper to compact and smooth the first mixture.

[0088] S8. High-temperature adhesive coating around the inner wall of the crucible: Use a brush to evenly apply SP38 water glass around the inner wall of the crucible, so that the inner wall of the crucible is wetted.

[0089] S9. Repairing the inner wall of the crucible: Apply the second mixture evenly to the inner wall of the crucible, with the thickness controlled between 2mm and 3mm.

[0090] S10. Crucible baking: Heat and hold the crucible in sequence according to the temperature gradient, specifically 85℃ for 50 minutes, 220℃ for 20 minutes, and 570℃ for 30 minutes.

[0091] After repair, the crucible was used for four consecutive furnaces without any detachment at the repair site. The crucible was scrapped after cracks appeared on the surface of the repair material. In total, the crucible was used 20 times, an increase of 4 times compared to the previous average of 18 times, representing an improvement of approximately 22%. In this embodiment, the alumina powder content in the first mixture was relatively high, and the mixture was generally dry, resulting in some detachment during the furnace repair process.

[0092] Table 1. Relevant performance parameters of the crucibles repaired in Examples 1-4

[0093] As shown in Table 1, the repair methods of this invention enable crucibles to continue to be used even after cracks, pits, or partial detachment occur, thereby extending the service life of the crucibles. Specifically, in Examples 1 and 2, the first mixture of alumina powder and SP50 water glass was prepared at a mass ratio of 2:1, and the second mixture of phosphorus-free refractory mortar and SP38 water glass was prepared at a mass ratio of 3:1. After repair, the crucible lifespan increased by approximately 33% and 38% respectively, with an average increase of approximately 35%. In Example 3, the first mixture of alumina powder and SP50 water glass was prepared at a mass ratio of 1.5:1, resulting in an approximately 11% increase in crucible lifespan after repair. In Example 4, the first mixture of alumina powder and SP50 water glass was prepared at a mass ratio of 2.5:1, resulting in an approximately 22% increase in crucible lifespan after repair. However, the first mixture was generally too dry, leading to some detachment during the furnace repair process. This indicates that crucible repair and life extension can be achieved when the mass ratio of alumina powder to SP50 water glass is within the range of 1.5:1 to 2.5:1. Among them, when the mass ratio is 2:1, the first mixture has better workability, filling density and anti-fall-off effect after repair.

[0094] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys, characterized in that, include: S1. Cool the refractory crucible to be repaired to room temperature; S2. Remove the contaminants from the inner wall of the refractory crucible to expose the local defects on the inner wall of the crucible. S3. Clean the foreign objects from the local defective areas, including cracks and localized detachment pits; S4. Mix the refractory powder with the first high-temperature binder to obtain a first mixture for filling the local defect area; S5. Mix the phosphorus-free refractory mortar with the second high-temperature adhesive to obtain a second mixture for covering the inner wall of the crucible. S6. Apply a third high-temperature adhesive to the interior and surrounding area of ​​the local defect to impregnate the local defect area; S7. Fill the local defect area with the first mixture and compact and level the filled first mixture. S8. Apply a fourth high-temperature adhesive to the inner wall of the refractory crucible to wet the inner wall of the crucible. S9. The second mixture is coated around the inner wall of the refractory crucible to form an inner wall repair and protection layer; S10. The refractory crucible coated with the first mixture and the second mixture is heated and baked in stages to solidify the first mixture and the second mixture and bond them to the inner wall of the crucible.

2. The repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys according to claim 1, characterized in that, The refractory powder is made of alumina powder, and the first high-temperature binder is made of SP50 water glass. The mass ratio of the alumina powder to the SP50 water glass is set between 1.5:1 and 2.5:

1.

3. The repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys according to claim 2, characterized in that, The purity of the alumina powder is not less than 99.9%.

4. The repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys according to claim 1, characterized in that, The second high-temperature adhesive uses SP38 water glass, and the mass ratio of the phosphorus-free refractory mortar to the SP38 water glass is 3:

1.

5. The repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys according to claim 1, characterized in that, The segmented heating and baking process includes sequentially performing the following steps: maintaining the temperature at 60℃ to 100℃ for 45 min to 60 min. Heat to 200℃~300℃ and hold for 15min~30min; Continue heating to 500℃~600℃ and hold for 20min~40min.

6. The repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys according to claim 1, characterized in that, In steps S6 and S8, the third and fourth high-temperature adhesives are SP38 type water glass.

7. The repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys according to claim 1, characterized in that, In step S7, after the first mixture is filled, the repair site is flush with the inner wall of the surrounding crucible, or the height of the repair site above the inner wall of the surrounding crucible does not exceed 2mm.

8. The repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys according to claim 1, characterized in that, In step S9, the thickness of the inner wall repair protective layer is 2mm to 3mm.

9. The repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys according to claim 1, characterized in that, Before the repair operation, when the previous furnace casting is completed, pour out the molten alloy from the crucible and keep the crucible tilted to reduce alloy slag and residual protrusions adhering to the furnace charge on the inner wall of the crucible.

10. The repair method for improving the lifespan of crucibles used in vacuum induction melting of high-temperature alloys according to claim 1, characterized in that, The refractory crucible to be repaired is specifically an alumina crucible.

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