CN112122545B - Preparation method of reusable investment casting shell, shell and casting process - Google Patents
Preparation method of reusable investment casting shell, shell and casting process Download PDFInfo
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- CN112122545B CN112122545B CN202010811591.6A CN202010811591A CN112122545B CN 112122545 B CN112122545 B CN 112122545B CN 202010811591 A CN202010811591 A CN 202010811591A CN 112122545 B CN112122545 B CN 112122545B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
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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
Abstract
The invention discloses a preparation method of a reusable investment casting shell, which comprises the following steps: providing a melting mold, a bottom plate, a top plate and a rigid cylinder; adhering the melting mold to a bottom plate, and sleeving a rigid cylinder outside the melting mold; pouring refractory slurry into a cavity between the rigid cylinder and the melting mold, sealing an upper opening of the rigid cylinder by using a top plate, and steaming by using steam; and (5) steaming and roasting to obtain a finished product of the investment casting shell. The refractory slurry mainly comprises a refractory material, water, an expanding agent, a wetting agent and a defoaming agent. The invention also discloses a reusable investment casting shell and an investment casting process. The invention can repeatedly utilize the shell for many times, does not produce solid waste, can shorten the production period and reduce the production cost.
Description
Technical Field
The invention relates to the technical field of investment casting, in particular to a preparation method of a reusable investment casting shell, the shell and a casting process.
Background
Investment casting generally refers to a casting method in which an fusible material is used to make an investment pattern having the same shape as a casting, a plurality of layers of refractory materials are coated on the surface of the investment pattern to make a shell, the investment pattern is melted and discharged from the shell, and a casting cavity is obtained through the processes of hardening, high-temperature roasting and the like, so as to perform casting molding. After the casting and forming are finished, the shell is required to be removed, and the shell removing process can be determined according to specific materials and physical and chemical properties of the shell, for example, acid or alkali corrosion removal is generally adopted for sintered ceramic shells, and mechanical methods such as vibration, shot blasting, sand blasting, shell blasting and the like can be adopted for grouting and curing shells.
In order to prevent the shell from cracking during casting and affecting the casting, the shell needs to have certain high-temperature strength. The common method for improving the high-temperature strength is to add a small amount of mineralizer into refractory materials (silica sand, quartz, corundum, mullite, bauxite, zircon sand and the like), so that the sintering temperature can be reduced, a solid solution is generated, and the high-temperature strength and the deformation resistance of the shell are improved. Common mineralizers such as alumina, calcium oxide, calcium aluminosilicate, and the like. However, the mineralizer is fused into the refractory material lattice during the high-temperature firing process, so that the chemical composition of the refractory material is changed, and the physical and chemical properties (especially the bonding strength) are changed, which makes the subsequent cleaning more difficult (especially difficult to clean by a mechanical method) on one hand, and also makes the used shell component more complex and difficult to recycle on the other hand. Existing manufacturers generally dispose of waste shell materials by landfill or disposal. Researchers also apply the waste shell material as a refractory material to other fields, for example, Chinese patent CN102773406B is to classify the waste shell material and use the waste shell material as a refractory aggregate of cast steel and cast iron coating; and the waste shell is used as the refractory aggregate of the refractory brick as in Chinese patent CN102951916A, and is used as the artificial spherical ceramic sand as in Chinese patent CN 109465378A. However, these techniques discuss the use of waste shells in other industries, but do not discuss how to reuse waste shells multiple times in the investment casting industry. In fact, for those skilled in the art, the recycling of shell materials is a long-felt but still unsuccessful technical problem.
In addition, for the preparation process of the shell, the existing shell-making process generally comprises the steps of dipping (or spraying) refractory paint on the surface of an investment (or forming a module after tree assembly), then scattering refractory powder on the surface of the refractory paint, and fixing the paint through the refractory powder. However, the shell thickness produced by this process is generally very small. In order to enable the shell with a small thickness to have a certain low-temperature strength and meet production requirements, a large amount of organic reinforcing agent (15-20%) is often added into a refractory coating in the prior art, and the low-temperature strength of the shell is improved through repeated dip coating and repeated sanding. However, even with multiple dip and multiple sanding processes, the shell thickness is relatively small. If the thickness of the shell is too high, some organic reinforcing agents positioned in the inner layer of the shell are difficult to be completely oxidized and decomposed, so that the defects of pouring and mold sticking are easily caused; and the oxidation temperature of the organic reinforcing agent close to the outer layer of the shell is correspondingly increased, so that cracks are generated in the oxidation process of the shell, and the high-temperature strength of the shell is reduced. In the prior art, the thickness of the shell is generally less than 5 mm.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a preparation method of a reusable investment casting shell, and the shell material can be recycled.
The invention also aims to provide a reusable investment casting shell.
The technical problem to be solved by the invention is to provide an investment casting process, which has the advantages of short production period, recyclable shell material and low cost.
In order to solve the above technical problems, the present invention provides a method for preparing a reusable investment casting shell, comprising:
(1) providing a melting mold, a bottom plate, a top plate, a rigid cylinder with an upper opening and a lower opening, and a refractory slurry; the refractory slurry comprises the following components in parts by weight:
60-80 parts of a refractory material, 15-25 parts of water, 0.1-1 part of an expanding agent, 0.5-2 parts of a wetting agent and 0.05-0.15 part of a defoaming agent;
(2) bonding the melting mold on the bottom plate, sleeving the rigid cylinder outside the melting mold, connecting the rigid cylinder with the bottom plate, and forming a cavity between the melting mold and the rigid cylinder;
(3) injecting the refractory slurry into the cavity to form a refractory green body layer;
(4) sealing the upper opening of the rigid cylinder by adopting a top plate to obtain a primary finished product; wherein, the top plate is provided with a pore;
(5) steaming and pressing the primary finished product in steam;
(6) and roasting the autoclaved primary product at 500-1150 ℃ to obtain a finished product of the investment casting shell.
As an improvement of the technical scheme, the refractory material is one or more of mullite, quartz sand, fused quartz, corundum, bauxite, silicon carbide and magnesium oxide;
the expanding agent is selected from the mixture of high-density polyethylene or polypropylene fiber or polyester polyol, isocyanate and catalyst.
As an improvement of the technical scheme, the refractory material is magnesium oxide, and the expanding agent is high-density polyethylene.
As an improvement of the technical scheme, the particle size of the magnesium oxide is 200-500 meshes.
As an improvement of the technical scheme, the bottom plate is made of acrylic resin or heat-resistant steel, the rigid cylinder is made of heat-resistant steel or titanium alloy or tungsten alloy, the rigid cylinder and the top plate are both provided with pores, and the pore diameter of each pore is less than or equal to 80 microns.
As an improvement of the technical scheme, in the step (3), a vacuum injection molding machine is adopted to inject the refractory slurry into the cavity to form a refractory blank layer;
the vacuum degree of the vacuum injection molding machine is 600-700 mmHg, and the stirring time is 2-4 min.
As an improvement of the technical scheme, in the step (4), the steam pressure is 0.25-0.5 MPa, the temperature is 90-150 ℃, and the steam pressure time is 10-50 min.
As an improvement of the technical scheme, the step (6) comprises the following steps:
(6.1) removing the bottom plate and the top plate in the autoclaved primary finished product;
and (6.2) roasting the primary finished product with the bottom plate and the top plate removed at 500-950 ℃ to obtain a finished product of the investment casting shell.
Correspondingly, the invention also discloses a recyclable investment casting shell which is prepared by the preparation method.
Correspondingly, the invention also discloses an investment casting process, which comprises the following steps:
(1) preparing an investment casting shell by adopting the preparation method, wherein a cavity for forming a casting is arranged in the shell;
(2) smelting an alloy material, pouring the alloy material into the cavity, and cooling;
(3) and cleaning the shell to obtain a finished casting.
As an improvement of the above technical solution, in the step (3), the shell is cleaned by a mechanical method.
The implementation of the invention has the following beneficial effects:
1. the refractory slurry of the present invention comprises only refractory material, water, expanding agent, wetting agent and defoaming agent, and no mineralizer is added. Wherein, water is completely removed in the shell steaming and roasting processes, and the expanding agent, the wetting agent and the defoaming agent are completely removed in the high-temperature roasting process. The chemical components and the lattice structure of the refractory material are unchanged after the refractory slurry is roasted and poured at high temperature, so that the refractory material can be recycled in the shell preparation process, and the technical problem that waste shells in the industry are difficult to recycle into the shells is solved.
2. The shell comprises an outer layer of a rigid cylinder body and a refractory material layer, wherein the raw materials of the refractory material layer comprise a refractory material and an expanding agent. The volume of the expanding agent rapidly expands when steam is steamed and pressed, isostatic pressing is formed on the refractory material, so that the refractory material particles are tightly combined, the refractory blank layer is well combined with the rigid cylinder body, and the shell is endowed with low-temperature strength. In addition, the rigid cylinder body of the outer layer provides high-temperature strength, and the smooth high-temperature pouring process is ensured.
3. The invention selects magnesium oxide as the refractory material of the shell, has high fire resistance strength and is not adhered in the high-temperature roasting process; meanwhile, the high-temperature expansion coefficient of the shell mold is large, and microcracks can be formed in the processes of high-temperature roasting, pouring and cooling after pouring, so that the refractory material layer can be cleaned by a simple mechanical method (shot blasting, vibration, shell blasting, sand blasting and the like), and the shell cleaning procedure is greatly simplified.
4. The shell preparation method of the invention does not need to stay among different working procedures, thereby greatly shortening the production period. The production cycle of the investment casting process is 8-10 h, the production cycle of the traditional multilayer shell-making casting process is not less than 72h, and the production cycle of the traditional gypsum type investment casting process is not less than 12 h.
Drawings
FIG. 1 is a flow chart of a method of making a reusable investment casting shell of the present invention;
FIG. 2 is a schematic view showing the connection state of the rear base plate, the melting mold and the rigid cylinder in step S2;
FIG. 3 is a schematic view showing the connection state of the back plate, the investment, the rigid cylinder, and the refractory blank layer after step S3;
FIG. 4 is a schematic view showing the connection state of the bottom plate, the investment, the rigid cylinder, the refractory blank layer, and the top plate after step S4.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below.
The conventional investment casting shell is difficult to be used as a shell material for repeated utilization, huge waste is caused, and the production cost is increased. To this end, the present invention provides a method of making a reusable investment casting shell, see fig. 1, comprising the steps of:
s1: providing a melting mold, a bottom plate, a top plate, a rigid cylinder and refractory slurry;
the investment material can adopt wax-based pattern material, rosin-based pattern material, resin-based pattern material or mixed pattern material, but is not limited to the above; the investment pattern may be prepared by a hot pressing method, a 3D printing method, but is not limited thereto. Preferably, in the invention, the investment material is a resin-based mold material and is formed by 3D printing; but 3D prints the shape of accurate control fired mold, promotes the casting precision.
The base plate is used for bonding and supporting the pattern molds so as to assemble the pattern molds into a module (tree group) (see fig. 2). The base plate is made of acrylic resin, PVC, PP or heat-resistant steel, preferably, the base plate is made of acrylic resin, and the base plate can facilitate the bonding of resin fusible patterns and the tree grouping of the fusible patterns.
The rigid cylinder is a cylinder which completely coats the investment pattern (or the tree-assembling rear module), and the upper part and the lower part of the rigid cylinder are provided with openings; the overall shape of the device is cylindrical, cubic, trapezoidal or spherical, but is not limited thereto; the cylindrical shell can better disperse stress and improve high-temperature strength.
In order to meet the temperature requirements in the high-temperature roasting and high-temperature pouring processes, the rigid cylinder is made of high-temperature-resistant heat-resistant steel, titanium alloy or tungsten alloy. Preferably, the rigid cylinder is made of heat-resistant steel, the cost of the heat-resistant steel is low, the working temperature of the rigid cylinder can reach about 900 ℃, and the process requirements of the invention can be completely met. For example, the heat-resistant steel may be 1Cr17Mo, 4Cr25Ni35Co15W5, or the like, but is not limited thereto.
The refractory slurry of the present invention has a small organic content and is therefore easily oxidized and decomposed. Therefore, the consumption of the refractory slurry can be increased, and the thickness of the refractory material layer is increased, so that the rigid cylinder can be made of heat-resistant steel with lower working temperature, and the production cost is reduced.
In addition, the rigid cylinder body is also provided with a pore which penetrates through the rigid cylinder body, and the aperture of the pore is less than or equal to 80 mu m; when the pores are autoclaved, the pores can be used as a channel for discharging moisture in the refractory slurry; the method can play a role in exhausting in later pouring, ensure that the shell has proper air permeability, and prevent casting defects such as insufficient pouring, air holes and the like.
The top plate is used for being matched with the rigid cylinder and the bottom plate and sealing the melting mold in a closed cavity formed by the rigid cylinder and the bottom plate, so that the refractory blank layer is densified after being subjected to expansion pressure of an expanding agent in the steam-pressing process and is combined with the rigid cylinder, and the shell is endowed with certain low-temperature strength. The top plate can be made of common steel, heat-resistant steel, titanium alloy or tungsten alloy. Preferably, a common steel material is selected. Correspondingly, the top plate is also provided with a pore which penetrates through the top plate, and the pore diameter of the pore is less than or equal to 80 mu m, so that water vapor can be discharged from the pore in the steam-pressing process, and refractory materials cannot be discharged from the pore.
The refractory slurry comprises the following components in parts by weight:
60-80 parts of refractory material, 15-25 parts of water, 0.1-0.5 part of expanding agent, 0.5-2 parts of wetting agent and 0.05-0.15 part of defoaming agent.
Wherein, the refractory material is selected from one or more of mullite, quartz sand, fused quartz, corundum, bauxite, silicon carbide and magnesium oxide, but is not limited to the above. Preferably, the refractory material is magnesium oxide, the refractory temperature is high, and the magnesium oxide is not adhered during high-temperature roasting; and the magnesium oxide has a large thermal expansion coefficient, and is heated and expanded in the cooling process after roasting, pouring and pouring to form microcracks, so that the refractory material layer can be cleaned by a simple mechanical method (shot blasting, vibration and the like), and the cleaning procedure of the shell is greatly simplified.
The using amount of the refractory material is 60-80 parts, and when the using amount is less than 60 parts, the compactness of a refractory blank layer can be influenced; when the amount is more than 80 parts, the fluidity of the refractory slurry is affected. The refractory is preferably used in an amount of 70 to 80 parts, and may be exemplified by 70 parts, 71 parts, 73 parts, 74 parts, 77 parts, and 79 parts, but is not limited thereto.
The granularity of the refractory material is 200-500 meshes, if the granularity is less than 500 meshes, the water requirement of the refractory slurry is increased, and a refractory green body layer is easy to crack and collapse in the steam-pressing process; if the grain size is larger than 200 meshes, the refractory body layer is not tightly bonded, and the compactness of the refractory body layer is also influenced. Preferably, the particle size of the refractory material is 300-425 meshes. Exemplary are 300 mesh, 325 mesh, 350 mesh, 375 mesh, 400 mesh, but not limited thereto.
The expanding agent is expanded in the later stage of steam pressing process, so that the refractory material in the closed space is subjected to isostatic pressing, the refractory blank layer is densified, and the refractory blank layer is combined with the rigid cylinder body, and the low-temperature strength of the shell is improved. The expanding agent can be selected from high-density polyethylene, polypropylene fiber or mixture of polyester polyol, isocyanate and catalyst; these materials all expand during autoclaving. Preferably, the expanding agent is high-density polyethylene with the molecular weight of 50000-100000 and the linear expansion rate of 2000-2400 multiplied by 10-7The temperature per DEG C is hundreds of times higher than the linear expansion coefficient of the refractory material in the formula of the refractory slurry, so that a larger compressive stress can be formed on the refractory material in the steam-pressing process, and the densification of the refractory material is promoted. In addition, the high-density polyethylene has low water absorption and the water requirement of the fire-resistant slurry is low; and the high-density polyethylene is easy to oxidize and remove during the later-stage roasting.
The amount of the expanding agent is 0.1-1 part, and when the amount of the expanding agent is less than 0.1 part, the densification of the refractory blank layer is difficult to promote; when the using amount of the expanding agent is more than 1 part, the pressure generated by steam pressure is too large, and the investment pattern is easy to damage. Preferably, the amount of the expanding agent is 0.1-0.8 part, more preferably 0.1-0.5 part; exemplary are, but not limited to, 0.1 parts, 0.15 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.45 parts.
The wetting agent promotes the combination of the expanding agent, the refractory material and water to form slurry with stable performance, so that the slurry can be formed by grouting. In addition, the wetting agent can also be completely excluded during the high-temperature calcination. The wetting agent can be selected from wetting dispersing agents produced by special chemical company, such as TEGO Dispers 755W, but is not limited thereto. The wetting agent is used in an amount of 0.5 to 2 parts, and illustratively, 0.6 part, 0.8 part, 1 part, 1.4 part, 1.6 part, 1.9 part, but not limited thereto.
The defoaming agent can eliminate foam in the refractory slurry, improve the overall performance of the refractory slurry and eliminate the defects of metal beans caused by bubbles. The defoaming agent can be completely eliminated in the high-temperature roasting process. Specifically, the defoaming agent may be a polyether defoaming agent, but is not limited thereto. The amount of the defoaming agent is 0.05 to 0.15 parts, and is illustratively 0.07 parts, 0.1 parts, 0.12 parts, and 0.14 parts, but is not limited thereto.
S2: bonding the fusible pattern on the bottom plate, sleeving the rigid cylinder outside the fusible pattern, and connecting the rigid cylinder with the bottom plate;
specifically, step S2 may include:
s21: combining the melting molds to form a module;
s22: adhering the module to the bottom plate;
specifically, the module can be adhered to the bottom plate by wax or glue; the bonded state is shown in fig. 2, in which 1 is a bottom plate, 2 is a die set, 21 is a melting mold, and 22 is a flow channel.
S23: sleeving a rigid cylinder outside the fusible pattern, and connecting a bottom plate with the rigid cylinder;
specifically, a cavity is arranged between the melting mold (or the mold set) and the rigid cylinder body and is used for injecting refractory slurry at the later stage.
S3: injecting the refractory slurry into the cavity to form a refractory green body layer;
specifically, the refractory slurry is injected into the cavity through a vacuum injection molding machine, the vacuum degree of the vacuum injection molding machine is 600-700 mmHg, and the stirring time is 2-4 min. The state after completion of step S3 is shown in fig. 3, where 5 is a refractory green body layer.
Specifically, the thickness of the refractory body layer is not particularly limited in the present invention, and those skilled in the art can select the thickness according to actual needs. Preferably, the minimum thickness of the refractory blank layer is more than or equal to 20 mm; because the refractory slurry of the present invention has very low organic content (less than or equal to 5%) and the thickness of the refractory body layer has less influence on the oxidation of the organic content, the present invention can use a thicker refractory body layer.
S4: sealing the upper opening of the rigid cylinder by adopting a top plate to obtain a primary finished product;
specifically, the top plate is used for covering the upper opening of the rigid cylinder body, so that the rigid cylinder body is integrally sealed. The state after completion of step S4 is shown in fig. 4, in which 6 is the top plate. Through-going pores are provided in the top plate so that water vapor can escape from the pores, but refractory particles cannot escape.
S5: steaming and pressing the primary finished product in steam;
specifically, steaming and pressing the primary finished product in a steaming and pressing kettle by adopting steam; and during steam pressing, the steam pressure is 0.25-0.5 MPa, the temperature is 90-150 ℃, and the steam pressing treatment time is 10-50 min. Under these conditions, the expanding agent can expand rapidly, densifying the refractory green body. Meanwhile, under the condition, moisture in the refractory blank layer can be quickly removed, and moisture is removed in steam, so that the refractory blank layer can be effectively prevented from cracking, and the refractory blank layer is ensured to have higher low-temperature strength.
In the present invention, the thickness of the refractory body layer is large, and if another heating method (such as direct dry air heating) is used, the surface moisture is likely to be discharged too quickly, and there is a possibility that a large number of cracks or even a defect of explosion may occur. The invention adopts steam to heat and drain water, which can eliminate the defect.
S6: and roasting the autoclaved primary product at high temperature to obtain a finished product of the investment casting shell.
Specifically, the step S6 includes:
s61: removing the bottom plate and the top plate in the autoclaved primary finished product;
after the bottom plate and the top plate are removed, the refractory blank layer can be fully contacted with air, so that the effective oxidation and removal of organic matters such as a melting mold, an expanding agent, a wetting agent, a defoaming agent and the like are facilitated.
S62: and (4) roasting the primary finished product with the bottom plate and the top plate removed at high temperature to obtain a finished product of the investment casting shell.
Wherein the roasting temperature is 500-1150 ℃, and preferably 500-950 ℃. In the invention, the main function of roasting is to remove organic substances, so that the roasting temperature is relatively low and the energy consumption is less. It is noted that in conventional investment casting processes, the shell material is sintered by firing to impart high temperature strength to the shell. The high-temperature strength of the shell mainly comes from the rigid cylinder, and the refractory material is not required to be sintered, so that the shell is prepared at a lower roasting temperature.
Correspondingly, the invention also discloses a reusable investment casting shell, which comprises a rigid cylinder body and a refractory material layer arranged in the rigid cylinder body; the refractory material layer is mainly prepared from the following raw materials in parts by weight:
60-80 parts of a refractory material, 15-25 parts of water, 0.1-0.5 part of an expanding agent, 0.5-2 parts of a wetting agent and 0.05-0.15 part of a defoaming agent;
various raw materials of the refractory material layer are tightly combined with the rigid cylinder body after grouting, autoclaved densification and high-temperature roasting to form the investment casting shell.
The shell of the invention adopts the rigid cylinder body as the outer layer which can provide high-temperature strength, so that the raw material of the refractory material layer of the invention does not need to be added with an inorganic mineralizer; furthermore, organic matters (expanding agent, wetting agent, defoaming agent) and the like in the raw materials of the refractory material layer are completely oxidized and removed in the high-temperature roasting process; that is to say, after high-temperature roasting, high-temperature pouring and cooling, the shell material only remains refractory material except the rigid cylinder body, and the chemical composition and the crystal structure of the shell material are not changed, so that the shell material can be recycled, and the problem that the waste shell material in the industry is difficult to recycle is thoroughly solved.
Meanwhile, the high-temperature strength of the shell mainly comes from the rigid cylinder, and the high-temperature strength of the shell cannot be greatly influenced by the microcracks of the refractory material layer. Therefore, MgO with a high thermal expansion coefficient can be completely used as the main refractory material for the refractory material layer. The microcracks generated by MgO in the processes of high-temperature roasting, high-temperature pouring and cooling greatly reduce the bonding strength of the refractory material layer, so that the shell can be removed by simple physical methods (shot blasting, vibration, sand blasting, high-pressure water spraying and ultrasonic waves), the removal difficulty of the shell is greatly reduced, and the investment casting process is simplified.
In addition, the expanding agent is introduced into the raw materials of the refractory material layer, and the expansion rate of the expanding agent is far greater than that of the refractory material in the high-temperature steam-pressing process, so that the powder of the refractory material is subjected to compressive stress, the refractory blank layer is densified, the refractory blank layer is ensured to have enough low-temperature strength, and the production requirement is met.
After the expanding agent is adopted, the content of organic matters in the refractory slurry is greatly reduced, and the oxidation amount in the roasting process is reduced. Therefore, the thickness of the refractory blank layer has less influence on the oxidation of the organic component; thereby allowing the present invention to be used with thicker refractory blank layers. After the thicker refractory blank layer is adopted, the requirement on the working temperature of the rigid cylinder is correspondingly reduced, so that the rigid cylinder can be made of common heat-resistant steel.
Correspondingly, the invention also provides an investment casting process, which comprises the following steps:
(1) preparing an investment casting shell, wherein a cavity for forming a casting is arranged in the shell;
(2) smelting an alloy material, pouring the alloy material into the cavity, and cooling;
(3) and cleaning the shell to obtain a finished casting.
Specifically, the shell may be removed by physical methods, such as, but not limited to, shot blasting, vibration, sand blasting, high pressure water blasting, ultrasonic waves, and the like.
In the investment casting process, the refractory blank layer is formed by a grouting process, and water vapor is directly used for steam-pressure drainage, so that different steps do not need to stay, and the production period is greatly shortened. Specifically, the production cycle of the investment casting process is 8-10 h; in the traditional multilayer shell-making investment casting process, drainage is required to be placed between every two shells, so that the production period is more than or equal to 72 hours; the traditional gypsum mold investment casting process needs to be placed for drainage after gypsum grouting, so that the production period is more than or equal to 24 hours.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
Claims (9)
1. A method of making a reusable investment casting shell comprising:
(1) providing a melting mold, a bottom plate, a top plate, a rigid cylinder with an upper opening and a lower opening, and a refractory slurry; the refractory slurry comprises the following components in parts by weight:
60-80 parts of a refractory material, 15-25 parts of water, 0.1-1 part of an expanding agent, 0.5-2 parts of a wetting agent and 0.05-0.15 part of a defoaming agent;
the refractory material is one or more of mullite, quartz sand, fused quartz, corundum, bauxite, silicon carbide and magnesium oxide;
the expanding agent is selected from a mixture of high-density polyethylene or polypropylene fiber or polyester polyol, isocyanate and a catalyst;
(2) bonding the melting mold on the bottom plate, sleeving the rigid cylinder outside the melting mold, connecting the rigid cylinder with the bottom plate, and forming a cavity between the melting mold and the rigid cylinder;
(3) injecting the refractory slurry into the cavity to form a refractory green body layer;
(4) sealing the upper opening of the rigid cylinder by adopting a top plate to obtain a primary finished product; wherein, the top plate is provided with a pore;
(5) steaming and pressing the primary finished product in steam;
(6) and roasting the autoclaved primary finished product at 500-950 ℃ to obtain a finished product of the investment casting shell.
2. The method of making a reusable investment casting shell according to claim 1 wherein the refractory material is magnesia and the expansion agent is high density polyethylene.
3. The method of making a reusable investment casting shell according to claim 2 wherein the magnesium oxide has a particle size of 200 to 500 mesh.
4. The method of claim 1, wherein the bottom plate is made of acrylic resin or heat resistant steel, the rigid cylinder is made of heat resistant steel or titanium alloy or tungsten alloy, and the rigid cylinder and the top plate are provided with pores having a pore size of 80 μm or less.
5. The method of making a reusable investment casting shell according to claim 1 wherein in step (3) the refractory slurry is injected into the cavity using a vacuum injection molding machine to form a refractory green body layer;
the vacuum degree of the vacuum injection molding machine is 600-700 mmHg, and the stirring time is 2-4 min.
6. The method for preparing the reusable investment casting shell according to claim 1, wherein in the step (5), the autoclaving pressure is 0.25-0.5 MPa, the temperature is 90-150 ℃, and the autoclaving time is 10-50 min.
7. The method of making a reusable investment casting shell according to claim 1 wherein step (6) comprises:
(6.1) removing the bottom plate and the top plate in the autoclaved primary finished product;
and (6.2) roasting the primary finished product with the bottom plate and the top plate removed at 500-950 ℃ to obtain a finished product of the investment casting shell.
8. A reusable investment casting shell prepared by the method of any one of claims 1 to 7.
9. An investment casting process, comprising:
(1) preparing an investment casting shell by the preparation method according to any one of claims 1 to 7, wherein a cavity for forming a casting is arranged in the shell;
(2) smelting an alloy material, pouring the alloy material into the cavity, and cooling;
(3) and cleaning the shell to obtain a finished casting.
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| CN (1) | CN112122545B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN87100343A (en) * | 1987-01-17 | 1988-04-06 | 哈尔滨工业大学 | The manufacture method of fusible pattern plaster mold and coating |
| CN1223913A (en) * | 1999-01-27 | 1999-07-28 | 苏凯蒂 | Mould material for investment casting and mould forming method |
| CN101332500A (en) * | 2007-06-28 | 2008-12-31 | 张克坚 | Negative-pressure casting method of cast |
| CN101745601A (en) * | 2008-12-19 | 2010-06-23 | 贵州云马飞机制造厂 | Method for directly casting zinc base alloy die blank on plaster mould |
| CN103586398A (en) * | 2013-11-27 | 2014-02-19 | 吴江市液铸液压件铸造有限公司 | Casting technology of stainless steel casting |
| CN105124874A (en) * | 2015-08-14 | 2015-12-09 | 广州番禺职业技术学院 | Production method for fine-ceramics inlayed jewelries |
| CN110893453A (en) * | 2019-12-02 | 2020-03-20 | 中北大学 | Gypsum mold precision casting method and device for magnesium alloy casting |
-
2020
- 2020-08-13 CN CN202010811591.6A patent/CN112122545B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN87100343A (en) * | 1987-01-17 | 1988-04-06 | 哈尔滨工业大学 | The manufacture method of fusible pattern plaster mold and coating |
| CN1223913A (en) * | 1999-01-27 | 1999-07-28 | 苏凯蒂 | Mould material for investment casting and mould forming method |
| CN101332500A (en) * | 2007-06-28 | 2008-12-31 | 张克坚 | Negative-pressure casting method of cast |
| CN101745601A (en) * | 2008-12-19 | 2010-06-23 | 贵州云马飞机制造厂 | Method for directly casting zinc base alloy die blank on plaster mould |
| CN103586398A (en) * | 2013-11-27 | 2014-02-19 | 吴江市液铸液压件铸造有限公司 | Casting technology of stainless steel casting |
| CN105124874A (en) * | 2015-08-14 | 2015-12-09 | 广州番禺职业技术学院 | Production method for fine-ceramics inlayed jewelries |
| CN110893453A (en) * | 2019-12-02 | 2020-03-20 | 中北大学 | Gypsum mold precision casting method and device for magnesium alloy casting |
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