A rapid induction melting bottom pouring type centrifugal casting composite structure crucible and application

Abstract

The application belongs to the technical field of vacuum induction melting and centrifugal casting, and particularly relates to a rapid induction melting bottom pouring type centrifugal casting composite structure crucible and application, which comprises an outer crucible and an inner crucible, the outer crucible is a one-off ceramic fiber crucible, the inner crucible is a reusable carbon crucible or ceramic crucible, the outer crucible and the inner crucible are combined through sintering, a first through hole is arranged in the middle of the inner crucible, a second through hole is arranged below the inner crucible, a third through hole is arranged in the lower part of the outer crucible, the central axis of the first through hole coincides with the central axis of the second through hole, the central axis of the second through hole coincides with the central axis of the third through hole, and the cross-sectional radius of the second through hole is smaller than the cross-sectional radius of the third through hole; compared with common carbon crucibles / ceramic fiber crucibles, the application has higher structural strength and anti-cyclic thermal cracking performance, and can ensure that the crucible is used at a higher use temperature and a faster heating rate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of centrifugal casting and vacuum induction melting, and particularly relates to a composite structure crucible for rapid induction melting bottom pouring type centrifugal casting and application. BACKGROUND

[0002] As an advanced casting process, the rapid induction melting bottom pouring process realizes rapid melting and bottom pouring of metals through induction heating principle, and is currently mainly used for producing complex structure castings such as high-temperature alloy turbine; since the rapid induction melting bottom pouring process can realize the heating, melting and bottom pouring process of alloy ingot in a short time, the production efficiency and casting quality are greatly improved.

[0003] As a special casting process, centrifugal casting can effectively cope with special-shaped structure castings with complex structure and uneven wall thickness by filling molten metal into a mold through centrifugal force in the production process; meanwhile, the centrifugal casting process is widely used in the fields of aviation, aerospace, automobile, ship and energy due to the advantages of good product filling effect, few pores and improved material utilization. In the production process of rapid induction melting bottom pouring type centrifugal casting, the crucible plays an important role from the start of induction melting to the casting of metal liquid before centrifugal forming.

[0004] At present, ceramic fiber crucibles made of aluminum silicate are used to produce rapid induction melting bottom pouring type centrifugal casting castings due to their excellent thermal shock resistance, light weight and low price. However, the product demand of rapid induction melting bottom pouring type centrifugal casting is continuously developing, and many high-melting-point (1600-1900℃) and high-activity alloys are used to produce rapid induction melting bottom pouring type centrifugal casting products. The aluminum silicate ceramic fiber crucible is limited by its material itself, and its own temperature resistance is 1550-1650℃, and aluminum silicate will react violently with active elements such as Y, Ti, Hf and Cr, which will not only reduce the quality of the castings but also cause the risk of cracking of the crucible; the aluminum silicate ceramic fiber crucible cannot meet the production demand of high-melting-point and high-activity alloy. SUMMARY

[0005] In view of the above problems, the application provides a composite structure crucible for rapid induction melting bottom pouring type centrifugal casting, which can not only meet the demand for thermal shock resistance of the crucible in the process of rapid induction melting bottom pouring type centrifugal casting, but also meet the demand for rapid induction melting bottom pouring of various high-melting-point and high-activity alloys.

[0006] The complete technical solution of the application comprises:

[0007] A kind of quick induction smelting bottom injection type centrifugal casting composite structure crucible, including outer layer crucible and inner layer crucible, the outer layer crucible is disposable ceramic fiber crucible;The inner layer crucible is reusable carbon crucible or ceramic crucible;Outer layer crucible and inner layer crucible are combined by sintering;

[0008] First through hole is equipped in the middle of inner layer crucible, second through hole is equipped below, third through hole is equipped in the lower part of outer layer crucible,

[0009] The center axis of first through hole and the center axis of second through hole coincide, the cross section radius of first through hole is greater than the cross section radius of second through hole;The center axis of second through hole and the center axis of third through hole coincide, the cross section radius of second through hole is greater than the cross section radius of third through hole.

[0010] Further, inner layer crucible is carbon crucible or ceramic crucible that has been sintered, and volume shrinkage due to phase change does not occur during sintering of the composite structure crucible, and the outer layer crucible is a ceramic fiber crucible made of alumina silicate or alumina, which shrinks in volume due to phase change during sintering of the composite structure crucible.

[0011] Further, after sintering of the composite structure crucible, a pressure is generated on the contact surface between the inner wall of the outer layer crucible and the outer wall of the inner layer crucible due to the volume shrinkage of the outer layer crucible.

[0012] Further, the preparation process of the quick induction smelting bottom injection type centrifugal casting composite structure crucible comprises:

[0013] (1) Assembly: mechanically combine the outer layer crucible and the inner layer crucible;

[0014] (2) Sintering: sinter the combined composite structure crucible at high temperature;

[0015] (3) Smelting: load and perform quick vacuum induction smelting centrifugal casting production of alloy ingot;

[0016] (4) Replace the outer layer crucible, the outer layer crucible is damaged after sintering and use, replace the damaged outer layer crucible, and perform the next cycle of centrifugal casting production.

[0017] Further, during sintering of the composite structure crucible, the volume expansion and shrinkage of the inner and outer layers of the crucible are cooperatively controlled by adjusting the wall thickness of the outer layer crucible, the outer diameter of the inner layer crucible, the inner diameter of the outer layer crucible, the draft angle of the inner layer crucible, the draft angle of the outer layer crucible, and the sintering schedule.

[0018] Further, a gap is left between the inner wall of the outer layer crucible and the outer wall of the inner layer crucible after mechanical combination in step (1).

[0019] Further, the wall thickness of the outer layer crucible is 9-20 mm.

[0020] Further, the inner diameter D of the outer crucible and the outer diameter d of the inner crucible satisfy the following relationship: D / d = 1.1~1.15.

[0021] Further, the inner diameter of the outer crucible is 55-80mm.

[0022] Further, the inner wall of the outer crucible and the outer wall of the inner crucible have different draft angles.

[0023] Further, the draft angle a1 of the inner wall of the outer crucible is greater than the draft angle a2 of the outer wall of the inner crucible.

[0024] Further, the draft angle a1 of the inner wall of the outer crucible and the draft angle a2 of the outer wall of the inner crucible satisfy the following relationship: a1-a2 = 2~3°.

[0025] Further, the draft angle a1 of the inner wall of the outer crucible is 3-9°.

[0026] Further, the sintering system is: heating to 200-300℃, holding for 10-15min; then heating to 500-600℃, holding for 15-20min; finally heating to 850-1050℃, holding for 30-45min and cooling.

[0027] Further, the application of the crucible in centrifugal casting.

[0028] Further, the height of the disposable ceramic fiber crucible is 280-380mm.

[0029] Further, the wall thickness of the inner crucible is 10-15mm, the inner diameter of the crucible is 40-70mm, and the height of the crucible is 245-345mm.

[0030] Further, the center axis of the first through hole coincides with the center axis of the second through hole, and the cross-sectional width of the first through hole is greater than that of the second through hole.

[0031] Further, the center axis of the second through hole coincides with the center axis of the third through hole, and the cross-sectional width of the second through hole is greater than that of the third through hole.

[0032] Further, the diameter of the first through hole cross section is: 40-70mm.

[0033] Further, the diameter of the second through hole cross section is: 15-25mm.

[0034] Further, the diameter of the third through hole cross section is: 18-28mm.

[0035] Further, the application of the composite structure crucible in rapid induction melting bottom pouring type centrifugal casting.

[0036] Compared with the prior art, the application has the advantages that:

[0037] (1) The outer layer crucible is a one-time ceramic fiber crucible, which has good thermal shock resistance and heat insulation effect, can well avoid direct contact between the inner layer crucible and the equipment, and avoid rigid collision between the inner layer crucible and the equipment to cause damage of the crucible and damage of the equipment due to high temperature of the inner layer crucible.

[0038] (2) The inner layer crucible is a compact, temperature-resistant and high-stability carbon crucible or ceramic crucible (yttrium oxide, zirconium oxide, etc.), which has good temperature resistance and high temperature stability, and can meet the smelting use requirements of high melting point and high activity alloy ingots containing Ti, Y, Hf and other active elements.

[0039] (3) The inner wall of the outer layer crucible and the outer wall of the inner layer crucible cooperate with each other, and after one production process is completed, the continuous use of the composite structure crucible is realized by replacing the light and cheap outer layer crucible, production cost is saved, and material waste is avoided.

[0040] (4) The composite structure crucible has higher structural strength and cyclic thermal cracking resistance than ordinary carbon crucible / ceramic crucible, and can ensure that the crucible meets the use at a higher use temperature and a faster heating rate. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a use flow chart of the rapid induction smelting composite structure crucible.

[0042] Figure 2 is a structural schematic view of the rapid induction smelting composite structure crucible.

[0043] Figure 3 is a top view of the rapid induction smelting composite structure crucible.

[0044] Figure 4 is a sectional view of the rapid induction smelting composite structure crucible.

[0045] In the figure: 1-outer layer crucible, 2-inner layer crucible, 3-first through hole, 4-second through hole, 5-third through hole. DETAILED DESCRIPTION

[0046] The application will be described in detail below in combination with the embodiments and the drawings, but it should be understood that the embodiments and the drawings are only used to exemplarily describe the application, and cannot constitute any limitation on the protection scope of the application. All reasonable modifications and combinations within the inventive concept of the application fall within the protection scope of the application.

[0047] As shown in Figures 1-4 A composite structure crucible for rapid induction melting bottom pouring type casting, comprising an outer layer crucible 1 and an inner layer crucible 2, the outer layer crucible 1 is a disposable ceramic fiber crucible; the inner layer crucible 2 is a reusable carbon crucible or a ceramic crucible. The preparation process comprises:

[0048] (1) Assembly: the outer layer crucible 1 and the inner layer crucible 2 are mechanically combined;

[0049] (2) Sintering: sintering the combined composite structure crucible at high temperature;

[0050] (3) Melting: loading, and performing rapid vacuum induction melting centrifugal casting production of alloy ingot;

[0051] (4) Failure and damage: the outer layer crucible 1 is damaged after sintering and use;

[0052] (5) Replace the outer layer crucible: replace the failed outer layer crucible 1, and recycle the production process of step (1) to step (4).

[0053] The disposable ceramic fiber crucible can be an aluminum silicate ceramic fiber crucible, and the crucible binder is one of silica sol, aluminum sol or zirconium sol. The inner layer crucible is a carbon crucible that can be used multiple times or a sintered ceramic crucible (yttrium oxide, zirconium oxide, etc.).

[0054] The main consideration for selecting the above-mentioned materials as the inner and outer crucibles is: first, the outer disposable ceramic fiber crucible has good thermal shock resistance and heat insulation effect, and as the outer crucible, it can well avoid the direct contact of the inner crucible with the equipment, rigid collision of the inner crucible and damage of the equipment due to the high temperature of the inner crucible. The inner layer crucible is a compact, temperature-resistant and stable carbon crucible or ceramic crucible, which has good temperature resistance and high temperature stability, and can meet the melting and use requirements of high melting point and high activity alloy ingot containing active elements such as Ti, Y and Hf.

[0055] Secondly, the inner layer crucible adopts carbon crucible or sintered ceramic crucible, which does not change phase during the preparation process of the composite structure crucible of the present application, and the volume hardly changes. The outer layer crucible is an aluminum silicate or aluminum oxide ceramic fiber crucible. The aluminum oxide ceramic fiber crucible changes from low temperature phase γ-Al2O3 to high temperature stable phase α-Al2O3 during sintering. γ-Al2O3 belongs to cubic crystal system, and there are a large number of vacancies in the crystal lattice, and the porosity is high. α-Al2O3 has a hexagonal close-packed structure, and the structure is more dense. The above irreversible phase change occurring during the sintering process will cause the volume to shrink. The aluminum silicate ceramic fiber gradually crystallizes from the amorphous glass phase at low temperature during sintering, and changes to the crystalline 3Al2O3 2SiO2, and volume shrinkage also occurs during this process. After high-temperature sintering of the composite crucible consisting of an outer crucible and an inner crucible, the outer crucible shrinks, creating pressure on the contact surface with the inner crucible, thus bonding them together.

[0056] In this process, the present invention designs the structural parameters of both components. When designing the structure, it is necessary to comprehensively consider various performance requirements and influencing factors, among which the main performance aspects include:

[0057] Strength of the outer crucible: As a disposable load-bearing structure, if its strength is insufficient, it may crack due to external force or thermal stress during use after sintering, causing the inner crucible to be exposed and damaged, thus affecting the overall service life.

[0058] Pressure at the contact surface of the inner and outer crucibles after sintering: Pressure is a key factor in the bonding between the inner and outer layers. Insufficient pressure at the contact surface will lead to low bonding strength and easy delamination or peeling, while excessive pressure may cause cracks in the inner crucible due to pressure concentration.

[0059] Replacement of the outer crucible after use of a composite crucible: As the outer crucible is a disposable structure, if it is difficult to peel off or the required detachment force is too large when replacing the outer crucible, it is easy to damage the inner layer, increase the subsequent processing cost or affect the purity of the melt.

[0060] The aforementioned influencing factors include:

[0061] Outer crucible wall thickness: It directly affects the strength of the outer layer. Increasing the wall thickness can improve the bending and impact resistance, but it will increase the amount of material used and the amount of sintering shrinkage. The larger the wall thickness, the greater the absolute value of volume shrinkage during sintering, and the pressure on the contact surface will increase accordingly, which will make it difficult to replace the outer crucible.

[0062] Shrinkage rate during the sintering process of the outer crucible: The greater the shrinkage rate, the greater the pressure on the contact surface, which will increase the bonding strength. However, if it is too large, it will cause excessive internal stress in the outer crucible, which may cause cracking during the sintering process and affect the subsequent replacement of the outer crucible.

[0063] The aforementioned performance and influencing factors work together to form a complex, nonlinear system that mutually influences and constrains each other. The three objectives of strength, pressure, and replacement of the outer crucible are mutually restrictive, making it impossible to achieve global optimization through a single parameter. Furthermore, the phase transformation shrinkage rate during the sintering of the outer ceramic fiber is affected by the temperature gradient and heating rate, exhibiting nonlinear characteristics that are difficult to predict using simple formulas. Process parameters such as sintering temperature and holding time also affect the shrinkage behavior, coupling with structural parameters (such as wall thickness) and increasing the dimensionality of optimization variables.

[0064] Therefore, the present application fully considers the complexity and interaction of various factors of the system, optimizes the structural parameters of the crucible through analysis and experimental verification, and obtains the following design results:

[0065] Based on the shrinkage of the outer crucible made of aluminum silicate or alumina ceramic fiber and the sintering process, the inner crucible and the outer crucible are designed to have a certain gap before sintering. Specifically, the inner diameter D of the outer crucible 1 and the outer diameter d of the inner crucible satisfy the following relationship:

[0066] D / d=1.1~1.15.

[0067] Specifically, the outer crucible wall thickness is 9-20mm, the inner diameter of the crucible is 55~97.75 mm, the inner crucible wall thickness is 10-15mm, the inner diameter of the crucible is 40-70mm, and the outer diameter is 50~85mm.

[0068] At the same time, the inner and outer crucible contact surfaces are designed to have different draft angles to improve the replacement ability of the outer crucible after use. Specifically, the outer crucible 1 inner wall draft angle a1 is greater than the inner crucible outer wall draft angle a2. Further, the outer crucible 1 inner wall draft angle a1 and the inner crucible outer wall draft angle a2 satisfy the following relationship:

[0069] a1- a2=2~3°.

[0070] Specifically, the outer crucible inner wall draft angle a1 is 4-11°, and the inner crucible outer wall draft angle a2 is 2-8°.

[0071] Considering that the inner crucible will expand to a certain extent and shrink during cooling during the sintering process. And the outer crucible also has shrinkage caused by phase change at different temperature intervals. Based on the above structural parameters, the present application simultaneously designs a sintering system matched therewith, so that the expansion and shrinkage at each stage are in a preset mode. The specific sintering process is: heating to 200-300℃, holding for 10-15min; then heating to 500-600℃, holding for 15-20min; finally heating to 850-1050℃, holding for 30-45min and cooling.

[0072] Other structures, the height of the inner crucible is 245-345mm. The height of the outer ceramic fiber crucible is 280-380mm. The inner crucible is provided with a first through hole 3 in the middle, a second through hole 4 below, and a third through hole 5 below the outer crucible,

[0073] The center axis of the first through hole coincides with the center axis of the second through hole, and the cross-sectional radius of the first through hole is greater than the cross-sectional radius of the second through hole; the center axis of the second through hole coincides with the center axis of the third through hole, and the cross-sectional radius of the second through hole is greater than the cross-sectional radius of the third through hole. Specifically, the diameter of the first through hole cross section is 40-70mm; the diameter of the second through hole cross section is 15-25mm; and the diameter of the third through hole cross section is 18-28mm.

[0074] When the aluminum silicate fiber is used as the outer layer crucible, the preparation method of the body is as follows: S1: using aluminum silicate ceramic fiber, solvent, organic monomer, crosslinking agent, preparing an aluminum silicate ceramic fiber crucible through gel injection molding in a mold;

[0075] Further, step S1 specifically includes:

[0076] S11: preparing a premix solution

[0077] The solvent, organic monomer and crosslinking agent are configured into a gel injection molding premix solution at a mass ratio of 90:9.5:0.5.

[0078] S12: fiber slurry preparation

[0079] The aluminum silicate fiber is put into a fiber beater to be chopped, and a dispersing agent is added to form a uniformly dispersed chopped fiber slurry.

[0080] S13: injection molding of the crucible body

[0081] The fiber slurry, binder and premix solution are mixed uniformly, an initiator is added, and after uniform stirring, the mold is injected, a catalyst is further added, and the mold and the body are quickly stirred and wrapped with a preservative film, and the gel reaction is carried out at 40℃.

[0082] S14: demolding and drying

[0083] The body that has been gelled is demolded, and then the body is placed in an oven, the oven is set to a temperature of 100 140℃, until the mass of the body no longer changes.

[0084] S15: high-temperature sintering

[0085] The dried body is placed in a high-temperature furnace for sintering, and the sintering temperature is 800℃ to 1500℃, to prepare an aluminum silicate ceramic fiber crucible.

[0086] Further, the organic monomer in S11 is acrylamide (AM), the crosslinking agent is N,N'-methylenebisacrylamide (MBAM), and the solvent is tert-butyl alcohol (TBA).

[0087] Further, the dispersant in S12 is cationic starch, and the length of the short-cut aluminum silicate fiber is 1-10 mm.

[0088] Further, the binder in S13 is silica sol, the initiator is 40wt.% ammonium persulfate aqueous solution, and the catalyst is 5wt.% tetramethyl ethylenediamine aqueous solution.

[0089] In the above step S1, in terms of the preparation of the premix solution, acrylamide (AM) generates free radicals and initiates monomer chain polymerization under the action of an initiator (ammonium persulfate) and a catalyst (tetramethyl ethylenediamine), and a crosslinking agent (MBAM) is crosslinked with the AM molecular chain through a bifunctional group to form a three-dimensional network gel structure. A very low monomer content (AM accounts for only 9.5% of the premix solution) and a crosslinking agent content (MBAM 0.5%) are used, and the solvent is mainly tert-butyl alcohol (TBA), which not only dissolves the monomer and the crosslinking agent, but also adjusts the viscosity of the system to ensure the flowability of the fiber slurry during mixing, greatly reducing the total amount of organic matter in the system, and volatilizing during drying to avoid residual organic impurities.

[0090] Tert-butyl alcohol accounts for 90%: to ensure low viscosity of the system, facilitating mixing of the fiber slurry; AM accounts for 9.5%: to provide enough monomers to form a gel network, and excessive amount will increase the brittleness of the green body; MBAM accounts for 0.5%: to control the crosslinking density and avoid affecting the toughness due to too dense network.

[0091] In terms of fiber slurry preparation, aluminum silicate fiber is used as a reinforcing phase to provide high-temperature strength, thermal shock resistance, and toughness. The fiber is short-cut (1-10 mm) to reduce entanglement and agglomeration of long fibers, balancing dispersibility and reinforcing effect. If the length is too short (<1 mm), the fiber reinforcing effect is weak and the matrix strength is insufficient; if the length is too long (>10 mm), the fiber is difficult to disperse and easy to entangle, resulting in decreased uniformity of the green body and poor formability.

[0092] Cationic starch is used as a dispersant to prevent fiber agglomeration in the slurry through electrostatic repulsion and steric hindrance effects, ensuring uniform distribution of the fiber in the green body. The fiber content is very high, and the gel network and silica sol work together to fix the fiber, preventing sedimentation and orientation.

[0093] Silica sol (binder) provides initial adhesion and helps stabilize the slurry before gelation. The gel network fixes the fiber through physical entanglement and chemical crosslinking to form a green body with certain strength, and the silica sol cooperates with the organic gel network to provide strength to the green body after gelation.

[0094] In terms of sintering, at 800℃, the organic gel network and starch dispersant begin to decompose, oxidize and volatilize. As the temperature rises (100℃ / h to 1500℃), the SiO2 provided by the silica sol sintering densification, partial melting to form a glass phase, and reaction or infiltration with the surface of the aluminum silicate fiber, forming a firm ceramic bond. The fiber itself remains stable at 1500℃, providing a skeleton reinforcement. A gradient temperature rise is used to avoid thermal stress cracking caused by the large difference in thermal expansion coefficient between the aluminum silicate fiber (low thermal expansion coefficient) and the SiO2 glass phase.

[0095] The above preparation process uses very low monomer content. Traditional gel casting focuses on high solid content, low viscosity slurry and in-situ solidification, which mainly uses relatively high monomer content (>10-15%) to ensure sufficient green body strength for subsequent demolding, molding and other operations. The present application greatly reduces the use of monomers and organics, and creatively introduces silica sol as part of the mixed slurry instead of subsequent impregnation, and makes it play a role in the early stage of molding (before / during gelation). Form a synergistic reinforcement with the organic network to meet the strength requirements.

[0096] Further, the application discloses application of the composite structure crucible in rapid induction melting bottom pouring type centrifugal casting.

[0097] The vacuum rapid induction remelting process of the alloy ingot is carried out by using the crucible, and the vacuum rapid induction remelting adopts a remelting pouring temperature gradient control device, and the pouring temperature gradient control device comprises a computing system, a temperature measuring mechanism, a rapid induction remelting mechanism and a bottom pouring crucible.

[0098] The computing system comprises a machine learning database subsystem, and can output target remelting process parameters according to target remelting characteristic parameters by using a trained machine learning model.

[0099] The target remelting characteristic parameters comprise total time of the alloy ingot from power-on to melting pouring in the remelting process, alloy liquid temperature at the time of pouring, temperature-time curve of the top of the alloy liquid in the remelting process, temperature-time curve of the middle of the alloy liquid in the remelting process and temperature-time curve of the bottom of the alloy liquid in the remelting process.

[0100] The target remelting process parameters comprise height and mass of the alloy ingot, remelting power-time process curve and distance-time curve of the distance between the coil bottom and the ingot bottom.

[0101] The rapid induction remelting mechanism is used for melting the alloy ingot, and the alloy ingot is remelted according to the target remelting process parameters and the melting sequence of the alloy ingot from top to bottom and from outside to inside is realized.

[0102] The temperature measuring mechanism comprises an infrared temperature measuring unit located at the top of the vacuum induction remelting equipment, a first wireless thermocouple built in the middle of the bottom pouring crucible, and a second wireless thermocouple located at the bottom of the bottom pouring crucible.

[0103] The target remelting process parameters are input into the remelting pouring temperature gradient control device, and a control signal is output in the computing system to move the induction remelting coil to the set position calculated and output, and to make the power supply output power according to the target remelting process parameters.

[0104] The temperature measuring mechanism monitors the real-time temperature of the top, middle and bottom of the alloy ingot during the vacuum induction remelting pouring process, and automatically adjusts the melting power in real time according to the target remelting characteristic parameters, to complete the vacuum induction remelting pouring process of the target alloy ingot.

[0105] The real-time automatic adjustment control algorithm is as follows:

[0106]

[0107] Wherein, u(t) is the control law output of automatic control, q is the remelting temperature rising influence factor, K p is the proportional parameter, e max is the maximum error of the target temperature and the measured temperature measured by the temperature measuring system during the remelting process, K i is the integral parameter, e mean is the average error of the target temperature and the measured temperature measured by the temperature measuring system during the remelting process, K d is the differential parameter, e(k) is the average error of the three temperature measuring points in the last 1 second in the current remelting process, is the average error of the three temperature measuring points in the last 11 seconds in the current remelting process, and k is the maximum value of the temperature collection time.

[0108] The target remelting characteristic parameters can be determined by historical experience, simulation experiment results screening, or according to the actual requirements of the casting process. Preferably, the computing system further comprises an ANSYS simulation software computing platform for realizing the simulation calculation of the rapid induction remelting and bottom pouring of alloy ingots of different sizes and compositions, and obtaining the optimized target remelting characteristic parameters.

[0109] The way of obtaining the target remelting process parameters according to the target remelting characteristic parameters by using the machine learning model is:

[0110] Step 1: According to the size of the induction coil and the size of the crucible, a simulation calculation model is constructed and simulation calculation is carried out; different simulation remelting process parameters are input, and corresponding multiple groups of simulation remelting characteristic parameters are calculated, which are used to construct a first database together with the original remelting process parameters and the original remelting characteristic parameter data obtained in the previous actual experiment;

[0111] Step 2: divide the data in the first database into training set and validation set in corresponding proportion; build and train the BP neural network model, wherein the input parameter is the remelting process parameter; the output parameter is the remelting characteristic parameter, and finally the trained BP neural network model is obtained;

[0112] Step 3: according to the target remelting characteristic parameter, the trained BP neural network model is used to output the target remelting process parameter.

[0113] Embodiment 1

[0114] A high-temperature alloy turbine blade engine rapid vacuum induction melting centrifugal casting composite structure crucible preparation process:

[0115] In this embodiment, referring to Figure 4 , the outer crucible 1 is an aluminum silicate fiber ceramic crucible, and the inner crucible 2 is a compact yttrium oxide ceramic crucible sintered at 1700 DEG C;

[0116] Further, the outer crucible has an inner diameter of 68 mm, a wall thickness of 15 mm, and a draft angle of 7 DEG;

[0117] Further, the inner crucible has an inner diameter of 50 mm, a wall thickness of 10 mm, and a draft angle of 5 DEG;

[0118] Further, referring to Figure 1 , the use process is as follows:

[0119] (1) Assembly: The outer crucible 1 and the inner crucible 2 are mechanically combined;

[0120] (2) Sintering: The combined composite structure crucible is sintered at high temperature;

[0121] (3) Melting: loading, rapid vacuum induction melting centrifugal casting production of alloy ingot;

[0122] (4) Failure and damage: the outer crucible 1 is damaged after sintering and use;

[0123] (5) Replace the outer crucible: replace the failed outer crucible 1, and cycle (1)-(4) production process.

[0124] Further, in this embodiment, the first through hole has a diameter of 50 mm and a length of 300 mm;

[0125] Further, in this embodiment, the second through hole has a diameter of 20 mm and a length of 20 mm;

[0126] Further, in this embodiment, the third through hole has a diameter of 18 mm and a length of 35 mm;

[0127] Further, the sintering process of the composite structure crucible is as follows: 200℃, 15min; 550℃, 15min; 1000℃, 45min;

[0128] Further, the alloy melted in the embodiment is a nickel-based high-temperature alloy, the alloy quality is 4.8-5Kg, the melting time is 90±20s, the pouring temperature is 1500-1550℃, and the centrifugal speed is 300r / min.

[0129] It can be understood that the inner layer crucible 2 provides a melting environment for melting the high-temperature alloy, avoiding alloy contamination caused by violent reaction with the crucible during the melting process; the outer layer crucible 1 plays a role in isolating the inner layer crucible 2 and the equipment, and avoiding direct collision and damage of the inner layer crucible 2 with the equipment due to equipment vibration during the rapid induction melting bottom pouring centrifugal casting process; the first through hole 3 and the second through hole 4, and the third through hole 5 have the same central axis, which ensures smooth and uniform pouring of the alloy liquid, reduces erosion and pouring deficiency, reduces the generation of oxidation inclusions, and reduces pouring defects.

[0130] Embodiment 2

[0131] A preparation process of a composite structure crucible for rapid vacuum induction melting and centrifugal casting of an aviation part:

[0132] In the embodiment, the outer layer crucible 1 is an alumina fiber ceramic crucible, and the inner layer crucible 2 is a carbon crucible with a purity of more than 99.9%;

[0133] Further, the inner diameter of the outer layer crucible is 70mm, the wall thickness is 20mm, and the draft angle is 8°;

[0134] Further, the inner diameter of the inner layer crucible is 50mm, the wall thickness is 12mm, and the draft angle is 6°;

[0135] Further, the use process is as follows:

[0136] (1) Assembly: The outer layer crucible 1 and the inner layer crucible 2 are mechanically combined;

[0137] (2) Sintering: The combined composite structure crucible is sintered at high temperature;

[0138] (3) Melting: loading, and performing rapid vacuum induction melting and centrifugal casting production of alloy ingots;

[0139] (4) Failure and damage: the outer layer crucible 1 is damaged after sintering and use;

[0140] (5) Replace the outer layer crucible: replace the failed outer layer crucible 1, and repeat the production process of (1)-(4).

[0141] Further, in the embodiment, the first through hole has a diameter of 50mm and a length of 280mm.

[0142] Further, in the embodiment, the second through hole has a diameter of 25mm and a length of 20mm.

[0143] Further, in the embodiment, the third through hole has a diameter of 24mm and a length of 35mm.

[0144] Further, the sintering process of the composite structure crucible is as follows: 250℃, 15min; 500℃, 10min; 1050℃, 35min.

[0145] Further, in the embodiment, the smelted alloy is titanium-aluminum alloy, the alloy quality is 1.9-2.1Kg, the smelting time is 95±20s, the pouring temperature is 1750-1800℃, and the centrifugal rate is 600r / min.

[0146] It can be understood that the inner layer crucible 2 provides a smelting environment for smelting high-temperature alloy, avoiding alloy pollution caused by violent reaction with the crucible during smelting; the outer layer crucible 1 insulates the inner layer crucible 2 and the equipment, and avoids the inner layer crucible 2 from being damaged by directly colliding with the equipment due to equipment vibration during the rapid induction smelting bottom pouring centrifugal casting process; the first through hole 3 and the second through hole 4 and the third through hole 5 have the same central axis, which ensures that the alloy liquid flows smoothly and uniformly, reduces erosion and pouring deficiency, reduces the generation of oxidation inclusions, and reduces pouring defects.

[0147] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

Claims

1. A composite structure crucible for rapid induction melting bottom-pouring centrifugal casting, characterized in that: It includes an outer crucible and an inner crucible, wherein the outer crucible is a disposable ceramic fiber crucible; the inner crucible is a reusable carbon crucible or ceramic crucible; the outer crucible and the inner crucible are bonded together by sintering. The inner crucible has a first through hole in the middle and a second through hole at the bottom; the outer crucible has a third through hole at the bottom. The central axis of the first through hole and the central axis of the second through hole coincide, and the cross-sectional radius of the first through hole is greater than that of the second through hole; the central axis of the second through hole and the central axis of the third through hole coincide, and the cross-sectional radius of the second through hole is greater than that of the third through hole.

2. The composite structure crucible for rapid induction melting bottom-pouring centrifugal casting according to claim 1, characterized in that, The outer crucible has an inner diameter of 55-80 mm and a wall thickness of 9-20 mm, while the inner crucible has a wall thickness of 10-15 mm and an inner diameter of 40-70 mm.

3. The rapid induction melting bottom-pouring centrifugal casting composite structure crucible according to claim 2, characterized in that, The inner wall of the outer crucible and the outer wall of the inner crucible have different draft angles.

4. A method for preparing a rapid induction melting bottom-pouring centrifugal casting composite structure crucible according to any one of claims 1-3, comprising: (1) Assembly: Mechanically assembling the outer crucible and the inner crucible; (2) Sintering: The assembled composite crucible is sintered at high temperature; (3) Melting: Loading materials and carrying out rapid vacuum induction melting and centrifugal casting of alloy ingots; (4) Replace the outer crucible. If the outer crucible fails or breaks after sintering, replace the failed outer crucible and proceed with the next cycle of centrifugal casting production.

5. The preparation method according to claim 4, characterized in that, During the sintering process of the composite crucible, the volume expansion and contraction of the inner and outer crucibles are controlled in a coordinated manner by adjusting the wall thickness of the outer crucible, the outer diameter of the inner crucible, the inner diameter of the outer crucible, the draft angle of the inner crucible, the draft angle of the outer crucible, and the sintering regime.

6. The preparation method according to claim 5, characterized in that, A gap is left between the inner wall of the outer crucible and the outer wall of the inner crucible after mechanical assembly.

7. The preparation method according to claim 6, characterized in that, The inner diameter D of the outer crucible and the outer diameter d of the inner crucible satisfy the following relationship: D / d = 1.1~1.

15.

8. The preparation method according to claim 7, characterized in that, The sintering process is as follows: heat to 200-300℃ and hold for 10-15 minutes; then heat to 500-600℃ and hold for 15-20 minutes; finally heat to 850-1050℃ and hold for 30-45 minutes before cooling.

9. The application of the composite structure crucible according to any one of claims 1-3 in rapid induction melting bottom-pouring centrifugal casting.

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