CN113462864A - Method for carrying out vacuum heat treatment on high-temperature alloy hollow casting with core - Google Patents
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 122
- 238000005266 casting Methods 0.000 title claims abstract description 115
- 238000000034 method Methods 0.000 title claims abstract description 77
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 62
- 239000000956 alloy Substances 0.000 title claims abstract description 62
- 238000004321 preservation Methods 0.000 claims abstract description 18
- 238000005495 investment casting Methods 0.000 claims abstract description 6
- 239000000919 ceramic Substances 0.000 claims description 38
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 17
- 229910052710 silicon Inorganic materials 0.000 claims description 17
- 239000010703 silicon Substances 0.000 claims description 17
- 229910000601 superalloy Inorganic materials 0.000 claims description 6
- 238000004140 cleaning Methods 0.000 claims description 5
- 239000013078 crystal Substances 0.000 abstract description 18
- 238000005058 metal casting Methods 0.000 abstract description 14
- 238000001953 recrystallisation Methods 0.000 abstract description 10
- 230000000630 rising effect Effects 0.000 description 6
- 239000002253 acid Substances 0.000 description 5
- 239000002585 base Substances 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000010791 quenching Methods 0.000 description 3
- 230000000171 quenching effect Effects 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000011179 visual inspection Methods 0.000 description 3
- 239000003513 alkali Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004886 process control Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000003044 adaptive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
- C21D1/773—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material under reduced pressure or vacuum
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/02—Sand moulds or like moulds for shaped castings
- B22C9/04—Use of lost patterns
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/22—Moulds for peculiarly-shaped castings
- B22C9/24—Moulds for peculiarly-shaped castings for hollow articles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D31/00—Cutting-off surplus material, e.g. gates; Cleaning and working on castings
- B22D31/002—Cleaning, working on castings
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/78—Combined heat-treatments not provided for above
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/10—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of nickel or cobalt or alloys based thereon
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B11/00—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/52—Alloys
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- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
- C30B33/02—Heat treatment
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Abstract
The invention relates to the field of high-temperature alloy investment precision casting and vacuum heat treatment, in particular to a method for carrying out vacuum heat treatment on a high-temperature alloy hollow casting with a core. The method adds a pretreatment process in the conventional vacuum heat treatment process of the high-temperature alloy hollow casting, and controls the heating rate and the heat preservation time of the heat treatment of the casting. The pretreatment process is that during casting heat treatment, the temperature is raised to 750-800 ℃ at a certain heating rate, heat preservation is carried out for a period of time, then the temperature is raised to 1100-1120 ℃ at a slow heating rate, heat preservation is carried out for a period of time, and then the temperature is raised to the casting heat treatment process temperature at a slow heating rate, so that the asynchrony of deformation caused by different expansion rates when the core and the metal casting expand by heating is relieved, the stress of the core on the casting at high temperature is reduced, and the phenomena of expansion crack, recrystallization and expansion crack of the single crystal and the directional casting during heat treatment of the isometric crystal hollow casting with the core are avoided.
Description
Technical Field
The invention relates to the field of high-temperature alloy investment precision casting and vacuum heat treatment, in particular to a method for carrying out vacuum heat treatment on a high-temperature alloy hollow casting with a core.
Background
In order to form a hollow cavity, a ceramic core is used as an aid for forming a high-temperature alloy hollow casting precisely cast by an investment mold, and the ceramic core is removed to form a cavity structure after the high-temperature alloy casting is cast. When the casting is subjected to vacuum heat treatment, the ceramic core is generally removed, in the process of removing the ceramic core, strong acid or strong base is required to be used for carrying out long-time treatment at high temperature and high pressure, and if the core is not completely removed or the strong acid or strong base for removing the core is not cleaned, the casting is melted in the heat treatment process. Therefore, a process method for carrying out vacuum heat treatment on the high-temperature alloy hollow casting with the core is needed to be designed, so that the process steps before the vacuum heat treatment of the high-temperature alloy hollow casting can be reduced, the probability of recrystallization of the single-crystal high-temperature alloy hollow casting is reduced, and the casting melting phenomenon caused by the heat treatment of the strong acid or strong base remained after core stripping is avoided.
Disclosure of Invention
The invention aims to provide a method for carrying out vacuum heat treatment on a high-temperature alloy hollow casting with a core, which can directly carry out vacuum heat treatment on the high-temperature alloy hollow casting without carrying out depoling treatment in a strong acid or strong alkali environment, and then carry out depoling treatment after the heat treatment is finished so as to avoid the phenomenon of casting melting in the heat treatment caused by unclean core removal or unclean acid-base cleaning.
In order to achieve the purpose of the invention, the technical scheme of the invention is as follows:
a method for carrying out vacuum heat treatment on a high-temperature alloy hollow casting with a core is characterized in that a pretreatment process is added in the conventional vacuum heat treatment process of the high-temperature alloy hollow casting, the temperature rise rate and the heat preservation time of the heat treatment of the casting are controlled, and the pretreatment process comprises the following steps:
1) cleaning the surface shell of the high-temperature alloy hollow casting, placing the cleaned surface shell into a vacuum heat treatment furnace, and vacuumizing the vacuum heat treatment furnace;
2) when the heat treatment temperature of the high-temperature alloy hollow casting is more than 800 ℃ and less than 1120 ℃, after the step 1), heating the furnace to 750-800 ℃ at a heating rate of 1-30 ℃/min, and preserving the heat for 40-60 min;
or when the heat treatment temperature of the high-temperature alloy hollow casting is above 1120 ℃, after the step 1), heating the furnace to 750-800 ℃ at a heating rate of 1-30 ℃/min, and preserving the heat for 40-60 min; then, the furnace temperature is increased to 1100-1120 ℃ at the heating rate of 0.5-5 ℃/min, and the temperature is kept for 40-60 min;
3) and (4) increasing the furnace temperature to the heat treatment process temperature of the casting at a temperature increasing rate of 0.5-5 ℃/min, and preserving the heat according to the process requirements.
The method for carrying out vacuum heat treatment on the high-temperature alloy hollow casting with the core comprises the steps of casting the high-temperature alloy hollow casting by adopting a precision investment casting method and adopting a silicon-based ceramic core as an auxiliary.
The high-temperature alloy hollow casting with the core is subjected to vacuum heat treatmentThe heat treatment of the high-temperature alloy hollow casting adopts a vacuum heat treatment method, and the vacuum degree is controlled to be less than or equal to 1 multiplied by 10 during the heat treatment-2Pa。
Preferably, in the step 2), the furnace temperature is increased to 750-800 ℃ at the temperature increasing rate of 1-10 ℃/min, and the furnace temperature is increased to 1100-1120 ℃ at the temperature increasing rate of 0.5-3 ℃/min.
Preferably, in the step 3), the furnace temperature is increased to the conventional vacuum heat treatment process temperature of the casting at the heating rate of 0.5-3 ℃/min.
Preferably, in the step 3), the vacuum degree is controlled to be less than or equal to 5 multiplied by 10 during heat treatment-3Pa。
The design idea of the invention is as follows:
when the high-temperature alloy hollow casting belt core is subjected to vacuum heat treatment, the high-temperature alloy casting and the ceramic core are heated asynchronously due to different thermal conductivities, and the expansion coefficients of the high-temperature alloy casting and the ceramic core are also different, so that the high-temperature alloy casting and the ceramic core are expanded asynchronously when being heated, stress is generated between the high-temperature alloy casting and the ceramic core, cracks are generated after the isometric crystal casting is heated, and recrystallization defects and serious cracks can occur on the single crystal and the directional casting. The invention designs a process method for carrying out vacuum heat treatment on a high-temperature alloy hollow casting strip core, which is characterized in that a pretreatment process is added in the vacuum heat treatment process, the temperature rise rate and the heat preservation time of the vacuum heat treatment are controlled, the expansion rate of a metal casting and the expansion rate of a ceramic core are mutually adapted within a certain time, the stress generated between the metal casting and the ceramic core is reduced, the expansion crack phenomenon cannot occur when the isometric crystal hollow casting strip core is subjected to heat treatment, and the recrystallization and the expansion crack phenomenon cannot occur on a single crystal and a directional casting.
The invention needs to add a pretreatment process in the vacuum heat treatment process of the high-temperature alloy hollow casting to control the heating rate and the heat preservation time of the heat treatment of the casting. Under the vacuum condition, the furnace temperature is increased to 750-800 ℃ at the rate of 1-30 ℃/min, namely the initial temperature of the silicon-based ceramic core for starting to generate large expansion, and the temperature is kept for 40-60 min; and then slowly raising the furnace temperature to 1100-1120 ℃ at a temperature rise rate of 0.5-3 ℃/min, namely, the temperature of the silicon-based ceramic core subjected to thermal expansion is finished, and preserving the heat for 40-60 min. The method of the invention optimizes the heat treatment process, adopts the pretreatment process of slow temperature rise and heat preservation of two temperature sections, can effectively reduce the stress action generated by different thermal conductivities and expansion coefficients when the ceramic core and the casting are heated, and can ensure that the mutual stress generated at different temperature sections between the casting and the core is reduced to a lower level when the silicon-based ceramic core of the high-temperature alloy casting is subjected to heat treatment, so that the expansion crack phenomenon can not occur when the strip core of the isometric crystal hollow casting is subjected to heat treatment, and the recrystallization and expansion crack phenomena can not occur on the single crystal and the directional casting.
The invention has the advantages and beneficial effects that:
1. the invention can lead the high-temperature alloy hollow casting to be subjected to heat treatment firstly and then to be subjected to core removal, thereby avoiding the strong acid and strong alkali in the core removal from polluting the casting and causing the casting to be melted in the heat treatment process.
2. The invention advances the heat treatment process of the high-temperature alloy hollow casting, reduces the possibility that the single crystal and the directional high-temperature alloy hollow casting are collided before heat treatment, and reduces the probability of recrystallization of the single crystal and the directional high-temperature alloy hollow casting in the heat treatment.
3. The invention reduces the mutual stress generated between the casting and the core at different temperature sections by adding the pretreatment process in the vacuum heat treatment process of the high-temperature alloy hollow casting, avoids the phenomenon of expansion crack when the isometric crystal hollow casting with the core is subjected to heat treatment, and avoids the phenomena of recrystallization and expansion crack of the single crystal and the directional casting.
Drawings
FIG. 1 is a schematic representation of dimensional changes of a superalloy casting at different temperature stages. In the figure, the abscissa Temperature represents the Temperature (. degree. C.) and the ordinate Length variation represents the change in the Length dimension (. mu.m).
FIG. 2 is a schematic diagram of dimensional changes of a silicon-based ceramic core at different temperature stages. In the figure, the temperature is 1-750-800 ℃ which is the temperature at which the silicon-based ceramic core begins to generate larger deformation, and the temperature is 2-1100-1120 ℃ which is the temperature at which the expansion of the silicon-based ceramic core is finished. The abscissa Temperature represents Temperature (. degree. C.) and the ordinate Length variation represents the change in Length dimension (. mu.m).
FIG. 3 is a schematic view of the pretreatment process control of the present invention. In the figure, 3-is a temperature rise section for rising the temperature to 750-800 ℃, 4-is a heat preservation section for rising the temperature to 750-800 ℃, 5-is a temperature rise section for rising the temperature to 1100-1120 ℃, 6-is a heat preservation section for rising the temperature to 1100-1120 ℃, 7-is a temperature rise section for rising the temperature to the temperature of the casting heat treatment process, and 8-is a heat preservation section for rising the temperature to the temperature of the casting heat treatment process. The abscissa Time represents Time (min) and the ordinate Temperature represents Temperature (. degree. C.).
FIG. 4 is a photograph of the equiaxed hollow casting strip of example 1 after solution vacuum heat treatment followed by depoling and etching.
FIG. 5 is a photograph showing the hollow cast single-crystal strip of example 2 after solution vacuum heat treatment for core removal and etching.
FIG. 6 is a photograph of the thin-walled equiaxed hollow casting of example 3 after vacuum heat treatment of the core and subsequent depoling and etching.
Detailed Description
In the specific implementation process, the invention adds a pretreatment process in the vacuum heat treatment process of the high-temperature alloy hollow casting to control the heating rate and the heat preservation time of the heat treatment of the casting. The pretreatment process is that during casting heat treatment, the temperature is raised to 750-800 ℃ at a certain heating rate, heat preservation is carried out for a period of time, then the temperature is raised to 1100-1120 ℃ at a slow heating rate, heat preservation is carried out for a period of time, and then the temperature is raised to the casting heat treatment process temperature at a slow heating rate, so that the asynchronous deformation caused by different expansion rates when the core and the metal casting expand by heating is relieved, the stress of the core on the casting at high temperature is reduced, the expansion crack phenomenon cannot occur when the isometric crystal hollow casting with the core is subjected to heat treatment, and the recrystallization and expansion crack phenomena cannot occur on the single crystal and the directional casting.
The invention will be further illustrated by the following examples, which are not intended to limit the invention thereto.
Example 1
In the embodiment, the solid solution vacuum heat treatment process of the K438 alloy hollow casting comprises the following steps: keeping the temperature for 2h at 1120 +/-10 ℃ and then carrying out gas quenching.
A pretreatment process is added in the vacuum heat treatment process of the high-temperature alloy hollow casting, and the method comprises the following steps:
cleaning the surface shell of the K438 alloy hollow casting which is subjected to precision investment casting, putting the surface shell into a vacuum heat treatment furnace, and vacuumizing to 5 multiplied by 10-3And after Pa, uniformly heating to 750 ℃ after 90min, preserving heat for 60min, uniformly heating to 1120 ℃ after 370min, and preserving heat for 2h according to the conventional process requirement of the K438 alloy. The casting is subjected to depoling and corrosion treatment on the K438 alloy hollow casting subjected to the vacuum heat treatment, and no crack of the casting is found through visual inspection, which is shown in figure 4.
Example 2
In this embodiment, the solution vacuum heat treatment process of the DD5 alloy hollow casting is as follows: and carrying out gas quenching after heat preservation for 2 hours at the temperature of 1295-1305 ℃.
A pretreatment process is added in the vacuum heat treatment process of the high-temperature alloy hollow casting, and the method comprises the following steps:
cleaning the surface shell of the DD5 alloy single crystal hollow casting subjected to precision investment casting, putting the casting into a vacuum heat treatment furnace, and vacuumizing to 5 multiplied by 10-3And after Pa, uniformly heating to 750 ℃ after 90min, preserving heat for 60min, uniformly heating to 1100 ℃ after 350min, preserving heat for 60min, then heating to 1300 ℃ according to the conventional process requirement of the DD5 alloy, and preserving heat for 2 h. The DD5 alloy single crystal hollow casting subjected to the vacuum heat treatment is subjected to depoling and corrosion treatment, and the casting is not cracked and recrystallized by visual inspection, which is shown in figure 5.
Example 3
In this embodiment, the vacuum heat treatment process of the K4951 alloy thin-wall hollow casting comprises the following steps: keeping the temperature at 1100 +/-10 ℃ for 4h, and then carrying out gas quenching.
A pretreatment process is added in the vacuum heat treatment process of the high-temperature alloy hollow casting, and the method comprises the following steps:
melting the molten steel with precisionCleaning surface shell of the cast K4951 alloy thin-wall hollow casting, placing the casting into a vacuum heat treatment furnace, and vacuumizing to 5 x 10-3And after Pa, uniformly heating to 750 ℃ after 90min, preserving heat for 60min, uniformly heating to 1100 ℃ after 350min, and preserving heat for 4h according to the conventional process requirement of the K4951 alloy. The hollow K4951 alloy casting subjected to the vacuum heat treatment is subjected to depoling and corrosion treatment, and no crack is found in the casting through visual inspection, which is shown in figure 6.
As shown in FIG. 1, the expansion of the superalloy casting is a more linear expansion change as a whole, while the dimensional changes of the silicon-based ceramic core at different temperature stages have different laws, as shown in FIG. 2. As can be seen from fig. 2, the silicon-based ceramic core deforms a small amount before 650 c, producing little stress with the metal casting. Starting from 650 ℃, the silicon-based ceramic core begins to generate expansion deformation, and when reaching 750-800 ℃, the silicon-based ceramic core generates larger expansion deformation, and the deformation rule is as follows: the silicon-based ceramic core exhibits a nearly linearly varying deformation, the amount of which increases with increasing temperature. In the temperature range, the expansion deformation of the core can generate certain stress on the metal casting, so that the heat preservation needs to be increased in the temperature range, the expansion of the metal casting and the expansion of the ceramic core are reduced, the metal casting and the ceramic core are adaptive to each other, and the generated stress is reduced. And in the temperature range of 800-1100 ℃, the ceramic core is always in a deformation stage which is approximately linearly expanded along with the temperature rise, and the temperature rise rate is controlled, so that the expansion deformation of the metal casting and the ceramic core is always in a relatively low change level, and the stress generated between the metal casting and the ceramic core is reduced. Within the range of 1100-1120 ℃, the expansion deformation of the silicon-based ceramic core is basically finished, the deformation quantity of the silicon-based ceramic core has a plurality of small fluctuations along with the temperature change, and the change temperature and the change quantity are different from the specific components of the silicon-based ceramic core. The heat preservation section is added in the temperature range, so that the expansion deformation of the metal casting and the ceramic core are mutually adapted, and the generated stress is reduced. At the temperature above 1120 ℃, the ceramic core does not expand any more but contracts and deforms, while the metal casting continues to expand and deform, and the slow heating rate can effectively reduce the stress effect between the ceramic core and the metal casting.
In addition to the requirements of the vacuum heat treatment process of the high-temperature alloy hollow casting, the heat preservation and the control of the heating rate in the pretreatment stage can effectively reduce the stress effect generated by different thermal conductivities and expansion coefficients of the ceramic core and the casting when the ceramic core and the casting are heated. As shown in figure 3, the schematic diagram of the pretreatment process control process shows that the method can reduce the stress caused by asynchronous expansion of the two sides due to different expansion coefficients and thermal conductivities between the casting and the core when the silicon-based ceramic core of the high-temperature alloy casting strip is subjected to heat treatment by optimizing the heat treatment process, thereby avoiding the phenomena of recrystallization and expansion cracking of the high-temperature alloy hollow casting strip when the vacuum heat treatment is carried out, reducing the working procedure time and increasing the efficiency.
The embodiment result shows that the invention can reduce the asynchronous deformation caused by different expansion rates when the core and the metal casting expand by heating, reduce the stress of the core on the casting at high temperature and avoid the recrystallization or cracks generated during the heat treatment of the casting with the core.
Claims (6)
1. A method for carrying out vacuum heat treatment on a high-temperature alloy hollow casting with a core is characterized in that a pretreatment process is added in a conventional vacuum heat treatment process of the high-temperature alloy hollow casting, the temperature rise rate and the heat preservation time of the heat treatment of the casting are controlled, and the pretreatment process comprises the following steps:
1) cleaning the surface shell of the high-temperature alloy hollow casting, placing the cleaned surface shell into a vacuum heat treatment furnace, and vacuumizing the vacuum heat treatment furnace;
2) when the heat treatment temperature of the high-temperature alloy hollow casting is more than 800 ℃ and less than 1120 ℃, after the step 1), heating the furnace to 750-800 ℃ at a heating rate of 1-30 ℃/min, and preserving the heat for 40-60 min;
or when the heat treatment temperature of the high-temperature alloy hollow casting is above 1120 ℃, after the step 1), heating the furnace to 750-800 ℃ at a heating rate of 1-30 ℃/min, and preserving the heat for 40-60 min; then, the furnace temperature is increased to 1100-1120 ℃ at the heating rate of 0.5-5 ℃/min, and the temperature is kept for 40-60 min;
3) and (4) increasing the furnace temperature to the heat treatment process temperature of the casting at a temperature increasing rate of 0.5-5 ℃/min, and preserving the heat according to the process requirements.
2. The method of claim 1, wherein the hollow superalloy casting is cast by precision investment casting with the assistance of a silicon-based ceramic core.
3. The method for vacuum heat treatment of hollow castings of superalloys according to claim 1, characterized in that the vacuum heat treatment is carried out for the hollow castings of superalloys by controlling the degree of vacuum to 1 x 10 or less during the heat treatment-2Pa。
4. The method for carrying out vacuum heat treatment on the hollow casting strip core of the high-temperature alloy according to claim 1, wherein preferably, in the step 2), the furnace temperature is increased to 750-800 ℃ at a temperature increasing rate of 1-10 ℃/min, and the furnace temperature is increased to 1100-1120 ℃ at a temperature increasing rate of 0.5-3 ℃/min.
5. The method for carrying out vacuum heat treatment on the hollow casting strip core of the high-temperature alloy according to claim 1, wherein in the step 3), the furnace temperature is preferably increased to the temperature of the conventional vacuum heat treatment process of the casting at the temperature increasing rate of 0.5-3 ℃/min.
6. A method for vacuum heat treating a hollow casting strip of superalloy as in claim 1, wherein preferably in step 3) the heat treatment is performed under a vacuum of 5 x 10 or less-3Pa。
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114235527A (en) * | 2021-12-13 | 2022-03-25 | 中国航发北京航空材料研究院 | Vacuum pretreatment method before fluorescence detection of isometric crystal high-temperature alloy casting |
| CN115786826A (en) * | 2022-12-08 | 2023-03-14 | 九江中船消防设备有限公司 | Pressure-removing and strengthening cooperative heat treatment method for aluminum bronze complex-structure casting |
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|---|---|---|---|---|
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| CN115786826A (en) * | 2022-12-08 | 2023-03-14 | 九江中船消防设备有限公司 | Pressure-removing and strengthening cooperative heat treatment method for aluminum bronze complex-structure casting |
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