CN115870453A - Lost foam casting method of alloy shield - Google Patents
Lost foam casting method of alloy shield Download PDFInfo
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- CN115870453A CN115870453A CN202111139940.5A CN202111139940A CN115870453A CN 115870453 A CN115870453 A CN 115870453A CN 202111139940 A CN202111139940 A CN 202111139940A CN 115870453 A CN115870453 A CN 115870453A
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Abstract
The invention belongs to the technical field of irradiation protection, and particularly relates to a lost foam casting method of an alloy shield, which comprises the following steps: step 1, preparing a mold core by using flammable foam materials; step 2, coating yttrium oxide coating which does not react with the special alloy at high temperature on the surface of the mold core, and drying to prepare a shell; step 3, coating mullite coating outside the yttrium oxide shell as a supporting and reinforcing layer; step 4, decomposing the foam model through high-temperature treatment and sintering the external coating to prepare a mould shell as a casting mould; step 5, embedding magnesia into the mould shell to ensure heat conduction, smelting special alloy, injecting the special alloy into the mould shell, and cooling to obtain a casting; and 6, machining the casting to a required size. The manufacturing process of the casting mould of the invention uses a large amount of light materials such as foam, the total weight is light and convenient to operate, and the casting mould occupies small space. The invention is one-time integral liquid molding, has high dimensional precision and avoids flash and dislocation. The invention adopts a disposable casting mould, takes the pieces by breaking the shells in the mould stripping mode, and can be used for casting the castings with more complex structures.
Description
Technical Field
The invention belongs to the technical field of irradiation protection, and particularly relates to a lost foam casting method of an alloy shielding body.
Background
In the common casting model materials, the liquid molten alloy is easy to react with most metal materials, most oxide ceramics and various silicates violently, and the casting requirement of the alloy is not met. The existing forming technology of the alloy shield is generally to adopt a graphite mould for casting, a graphite block is used for processing an upper split type concave cavity casting mould and a lower split type concave cavity casting mould, an upper mould is provided with a pouring gate structure, alloy melt is injected after the upper mould and the lower mould are assembled, and after cooling, the casting is taken out by splitting the moulds. The process has the following problems:
1) The graphite mold is low in density, and in order to meet the molding requirement of alloy castings, the designed graphite mold occupies too large space and is difficult to realize in process, so that the graphite mold is not suitable for casting molding of large-volume castings.
2) The split type mould structure leads to the foundry goods to produce the overlap defect at the die joint, and the mould assembly dislocation also leads to foundry goods overall dimension precision low.
3) Is limited by a mold stripping mode, and cannot meet the molding requirement of a casting with a complex structure.
Disclosure of Invention
Aiming at the defects, the invention aims to provide a lost foam casting method of an alloy shielding body, which meets the shielding requirement of certain mobile emergency irradiation sterilization equipment.
The technical scheme of the invention is as follows:
the invention relates to a lost foam casting method of an alloy shield, which mainly comprises the steps of manufacturing a decomposable mold core, preparing an inner wall high-temperature-resistant inert coating, preparing an outer side reinforcing support coating, decomposing the mold core, sintering a mold shell, casting and processing.
The main process flow of the invention is as follows:
step 1, manufacturing a mold core. Flammable foam is used as the core material. In the aspect of core size design, considering that the alloy casting shrinkage is 3%, a model size l0=1.03l is calculated on the basis of an alloy product design size l, and 20% of the total height of an additional product in the height direction of the core is used as a riser. After the size design of the mold core is completed, the foam is cut and molded by using a linear cutting device, and splicing and assembling are carried out by using sticky wax to prepare the easily-decomposed foam mold core corresponding to a casting product.
And 2, preparing the high-temperature-resistant inert coating on the inner wall. Given that yttria is chemically stable enough not to react with molten metal, a nanoscale yttria powder was used to mix yttria sol according to a mass 2:1 as the inner wall high temperature resistant coating, and adding a surfactant. Spraying yttrium oxide coating on the surface of the easily decomposed foam mold core, uniformly sticking a layer of 300-mesh yttrium oxide fine sand after spraying, drying for 12 hours at the temperature of 23-28 ℃ under the environment of 55-65% of humidity, and repeating the coating and drying operation for 2-3 times until an yttrium oxide coating shell with the thickness of more than 3mm is formed on the surface of the easily decomposed foam mold core.
And 3, preparing an outer side reinforcing support coating. Mixing mullite powder with silica sol according to the mass ratio of 3.5:1 as reinforcing support coating, and adding surfactant. The mullite coating is uniformly coated outside the yttria coating shell, a layer of mullite sand with 120 meshes is uniformly adhered and hung, and after the mullite sand is dried for 12 hours at the temperature of 23-28 ℃ and under the humidity of 55-65%, the coating and drying operation is repeated for 15-20 times until the total thickness of the mullite reinforced support coating shell reaches more than 30 mm.
And 4, decomposing the mold core and sintering the mold shell. And (3) sintering the easily-decomposed foam mold core externally coated with the yttrium oxide high-temperature-resistant inert coating and the mullite reinforced support coating by adopting heat preservation at 950 ℃ for 4 hours to ensure that the coating is sintered and strengthened, and obtaining the mold shell serving as the casting mold after the foam mold core is completely combusted and decomposed.
And 5, casting. Embedding the mould shell into a magnesia barrel to ensure uniform heat conduction, enabling a riser above the mould shell to be 4-5 mm higher than magnesia, smelting an alloy ingot to 1200 ℃, injecting the alloy ingot into a mould shell under a vacuum condition, cooling, and breaking the mould shell to obtain a casting.
And 6, processing. And (3) after the stress relief annealing is carried out on the casting at 800 ℃, a dead head is cut off, and the size of the casting is finely trimmed.
The invention has the beneficial effects that:
compared with the existing preparation method of the conventional alloy casting, the preparation method has the following remarkable advantages:
1) The manufacturing process of the casting mould of the invention uses a large amount of light materials such as foam, the total weight is light and convenient to operate, and the casting mould occupies small space.
2) The invention is one-time integral liquid forming, has high size precision and avoids flash and dislocation.
3) The invention adopts a disposable casting mould, takes the pieces by breaking the shells in the mould stripping mode, and can be used for casting the castings with more complex structures.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
Example one
Step 1, a certain plate-shaped shield body has the outline dimension of 535 multiplied by 290 multiplied by 50mm. A mold core is made of foam materials, wire cutting is used for manufacturing the mold core with the size of 661 multiplied by 299 multiplied by 52mm, and a face with one end multiplied by 52mm is used as a riser.
And 2, uniformly mixing 2kg of nano yttrium oxide powder and 1kg of yttrium oxide sol, adding 10ml of surfactant, spraying the mixture on the surface of a mold core by using a spray gun, uniformly sticking and hanging a layer of 300-mesh yttrium oxide fine sand after spraying, drying for 12 hours at the temperature of 23-28 ℃ under the environment with the humidity of 55-65%, and repeating the coating and drying operations for 2 times.
And 3, uniformly mixing 35kg of mullite powder and 10kg of silica sol, adding 100ml of surfactant, soaking the mold core in the coating for 10s, taking out, uniformly sticking and hanging a layer of mullite sand with a size of 120 meshes, drying for 12 hours at the temperature of 23-28 ℃ under the environment with the humidity of 55-65%, and repeating the coating and drying operation for 18 times.
And 4, putting the mold core with the shell into a box furnace, then carrying out heat treatment at 950 ℃ for 4 hours, cooling the mold core with the shell to room temperature in the furnace, and taking out the mold shell.
And step 5, filling the mould shell into a magnesia sand barrel, enabling a riser to be 5mm higher, smelting the alloy to 1200 ℃ under a vacuum condition, pouring the alloy into the mould shell, cooling for 24 hours in a vacuum furnace, and then discharging vacuum to take out the casting.
And 6, cutting and sawing the casting riser, and machining to the size of the drawing by using a milling machine.
Example two
Step 1, the outer contour dimension of a certain square-shaped shield is 360 multiplied by 620 multiplied by 80mm, and the inner frame contour dimension is 250 multiplied by 400 multiplied by 80mm. The mold core is made of foam material, and the dimensions of the mold core are 371X 766X 83mm by using wire cutting, one end of the inner frame contour is 242X 389X 83mm, and the surface of the inner frame contour is 242X 83mm to be used as a riser.
And 2, uniformly mixing 2kg of nano yttrium oxide powder and 1kg of yttrium oxide sol, adding 10ml of surfactant, spraying the mixture on the surface of a mold core by using a spray gun, uniformly sticking and hanging a layer of 300-mesh yttrium oxide fine sand after spraying, drying for 12 hours at the temperature of 23-28 ℃ under the environment with the humidity of 55-65%, and repeating the coating and drying operations for 2 times.
And 3, uniformly mixing 35kg of mullite powder and 10kg of silica sol, adding 100ml of surfactant, soaking the mold core in the coating for 10s, taking out, uniformly sticking and hanging a layer of mullite sand with a size of 120 meshes, drying for 12 hours at the temperature of 23-28 ℃ under the environment with the humidity of 55-65%, and repeating the coating and drying operation for 20 times.
And 4, putting the mold core with the shell into a box furnace, then carrying out heat treatment at 950 ℃ for 4 hours, cooling the mold core with the shell to room temperature in the furnace, and taking out the mold shell.
And 5, filling the mould shell into a magnesia sand barrel, enabling a riser to be 5mm higher, smelting the alloy to 1200 ℃ under a vacuum condition, pouring the alloy into the mould shell, cooling for 24 hours in a vacuum furnace, and then vacuumizing to take out the casting.
And 6, cutting and sawing the casting riser, and machining to the size of the drawing by using a milling machine.
EXAMPLE III
Step 1, the external contour dimension of a box-shaped shield is 330 multiplied by 230 multiplied by 130mm, and the wall thickness is 40mm. The mould core is made of foam materials, a plurality of plates with the thickness of 45mm are manufactured by wire cutting, and the mould core is assembled into a box-shaped mould core with the outer contour of 340 multiplied by 237 multiplied by 134mm and the thickness of 45mm and an additional riser and pouring gate structure through bonding wax.
Step 2, uniformly mixing 2kg of nano yttrium oxide powder and 1kg of yttrium oxide sol, adding 10ml of surfactant, spraying the mixture on the surface of a mold core by using a spray gun, uniformly sticking and hanging a layer of 300-mesh yttrium oxide fine sand after spraying, drying the mixture for 12 hours at the temperature of 23-28 ℃ in an environment with the humidity of 55-65%, and repeating the coating and drying operations for 2 times.
And 3, uniformly mixing 35kg of mullite powder and 10kg of silica sol, adding 100ml of surfactant, soaking the mold core in the coating for 10s, taking out, uniformly sticking and hanging a layer of mullite sand with a size of 120 meshes, drying for 12 hours at the temperature of 23-28 ℃ under the environment with the humidity of 55-65%, and repeating the coating and drying operation for 20 times.
And 4, putting the mold core with the shell into a box furnace, then carrying out heat treatment at 950 ℃ for 4 hours, cooling the mold core with the shell to room temperature in the furnace, and taking out the mold shell.
And 5, filling the mould shell into a magnesia sand barrel, enabling a riser to be 5mm higher, smelting the alloy to 1200 ℃ under a vacuum condition, pouring the alloy into the mould shell, cooling for 24 hours in a vacuum furnace, and then vacuumizing to take out the casting.
And 6, cutting and sawing a casting runner and a riser, and machining to the dimensions of the drawing by using a milling machine.
In the disclosed embodiments of the present invention, only methods related to the disclosed embodiments are referred to, and other methods may refer to general designs, and under the condition of no conflict, the same embodiment and different embodiments of the present invention may be combined with each other;
the above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that are within the spirit and principle of the present invention are intended to be included in the scope of the present invention.
Claims (10)
1. A lost foam casting method of an alloy shield comprises the steps of 1, manufacturing a mold core, 2, preparing a high-temperature-resistant inert coating on the inner wall, 3, preparing a reinforcing support coating on the outer side, 4, decomposing the mold core, sintering a mold shell, 5, casting and 6, processing; the method is characterized in that:
step 1, manufacturing a mold core, wherein an alloy product calculation model is 1.03l times of an alloy product design size model, and 20% of the total height of an additional product in the corresponding direction of the mold core in the height direction is used as a riser; after the size design of the mold core is finished, cutting and molding foam by using a linear cutting device, and splicing and assembling by using viscous wax to prepare the easily-decomposed foam mold core corresponding to a casting product;
step 2, preparing an inert coating with high-temperature resistance on the inner wall; given that yttria is chemically stable enough not to react with any molten specialty metal, nano-sized yttria powder was used to mix yttria sol according to a mass 2:1, uniformly mixing the components to obtain an inner wall high-temperature-resistant coating, and adding a surfactant; spraying yttrium oxide coating on the surface of the easily-decomposed foam mold core, uniformly sticking and hanging a layer of yttrium oxide fine sand after spraying, drying at the temperature of 23-28 ℃ under the environment with the humidity of 55-65%, and repeating the coating and drying operation for 2-3 times until an yttrium oxide coating shell with the thickness of more than 3mm is formed on the surface of the easily-decomposed foam mold core;
step 3, preparing an outer side reinforcing support coating; using mullite powder mixed with silica sol as a reinforcing support coating, and adding a surfactant; uniformly coating mullite paint outside an yttrium oxide coating shell, uniformly sticking and hanging a layer of mullite sand, drying at the temperature of 23-28 ℃ under the environment with the humidity of 55-65%, and repeating the coating and drying operation for 15-20 times until the total thickness of the mullite reinforced support coating shell reaches more than 30 mm;
step 4, decomposing the mold core and sintering the mold shell; sintering the easily-decomposed foam mold core, and completely burning and decomposing the foam mold core to obtain a mold shell serving as a casting mold;
step 5, casting; embedding the mould shell into a magnesia barrel to ensure uniform heat conduction, enabling a riser at the upper part to be 4-5 mm higher than magnesia, smelting an alloy ingot, injecting the alloy ingot into a mould shell under a vacuum condition, cooling, and then breaking the mould shell to obtain a casting;
step 6, processing; and (4) after the stress relief annealing is carried out on the casting, a dead head is cut off, and the size of the casting is finely trimmed.
2. A method of lost foam casting of an alloy shield as recited in claim 1, wherein: in the step 1, flammable foam materials are used as the raw materials of the mold core.
3. A method of lost foam casting of an alloy shield as recited in claim 1, wherein: and 2, spraying the yttrium oxide coating on the surface of the easily decomposed foam mold core, and uniformly adhering and hanging a layer of 300-mesh yttrium oxide fine sand after spraying.
4. A lost foam casting method of an alloy shield as set forth in claim 1 or 3, wherein: and 2, spraying the yttrium oxide coating on the surface of the easily decomposed foam mold core, uniformly adhering and hanging a layer of yttrium oxide fine sand after spraying, and drying for 12 hours at the temperature of 23-28 ℃ under the environment with the humidity of 55-65%.
5. A method of lost foam casting of an alloy shield as recited by claim 1, wherein: step 3, mixing mullite powder with silica sol according to a mass ratio of 3.5:1 as reinforcing support coating.
6. A lost foam casting method of an alloy shield as set forth in claim 1 or 5, wherein: and uniformly coating the mullite coating outside the yttrium oxide coating shell, uniformly sticking and hanging a layer of mullite sand with 120 meshes, and drying for 12 hours at the temperature of 23-28 ℃ under the environment with the humidity of 55-65%.
7. A method of lost foam casting of an alloy shield as recited by claim 1, wherein: and 4, sintering the easily-decomposed foam mold core externally coated with the yttrium oxide high-temperature-resistant inert coating and the mullite reinforced support coating by adopting heat preservation at 950 ℃ for 4 hours to ensure the sintering reinforcement of the coating.
8. A method of lost foam casting of an alloy shield as recited in claim 1, wherein: and 5, burying the mould shell into a magnesia barrel to ensure uniform heat conduction, enabling a riser above the magnesia barrel to be 4-5 mm higher, and smelting the alloy ingot to 1200 ℃.
9. A method of lost foam casting of an alloy shield as recited in claim 1, wherein: and 6, after stress relief annealing is carried out on the casting at 800 ℃, a riser is cut off, and the size of the casting is finely finished.
10. A lost foam casting method of an alloy shield comprises the steps of 1, manufacturing a mold core, 2, preparing a high-temperature-resistant inert coating on the inner wall, 3, preparing a reinforcing and supporting coating on the outer side, 4, decomposing the mold core, sintering a mold shell, 5, casting and 6, processing; the method is characterized in that:
step 1, manufacturing a mold core, wherein flammable foam materials are used as raw materials of the mold core, an alloy product calculation model is 1.03l times of the alloy product design size model, and 20% of the total height of the product in the corresponding direction of the mold core in the height direction is used as a riser; after the size design of the mold core is finished, cutting and molding foam by using a linear cutting device, and splicing and assembling by using viscous wax to prepare the easily-decomposed foam mold core corresponding to a casting product;
step 2, preparing an inert coating with high-temperature resistance on the inner wall; given that yttria is chemically stable enough not to react with any of the molten specialty metals, a nano-sized yttria powder was used to mix yttria sol according to a mass 2:1, uniformly mixing the components to obtain an inner wall high-temperature-resistant coating, and adding a surfactant; spraying yttrium oxide coating on the surface of the easily decomposed foam mold core, uniformly sticking a layer of yttrium oxide fine sand after spraying, drying for 12 hours at the temperature of 23-28 ℃ under the environment of 55-65% of humidity, and repeating the coating and drying operation for 2-3 times until an yttrium oxide coating shell with the thickness of more than 3mm is formed on the surface of the easily decomposed foam mold core;
step 3, mixing mullite powder with silica sol according to the mass ratio of 3.5:1 as reinforcing support coating, and adding surfactant. Uniformly coating the mullite coating outside an yttrium oxide coating shell, uniformly sticking and hanging a layer of mullite sand with 120 meshes, drying for 12 hours at the temperature of 23-28 ℃ under the environment with the humidity of 55-65%, and repeating the coating and drying operation for 15-20 times until the total thickness of the mullite reinforced support coating shell reaches more than 30 mm;
step 4, decomposing the mold core and sintering the mold shell, and sintering the easily decomposed foam mold core externally coated with the yttrium oxide high-temperature resistant inert coating and the mullite reinforced support coating by adopting heat preservation at 950 ℃ for 4 hours to ensure that the coating is sintered and strengthened, and completely burning and decomposing the foam mold core to obtain the mold shell serving as the casting mold;
step 5, casting; embedding the mould shell into a magnesia barrel to ensure uniform heat conduction, enabling a riser above the mould shell to be 4-5 mm higher than magnesia, smelting an alloy ingot to 1200 ℃, injecting the alloy ingot into a mould shell under a vacuum condition, cooling and then breaking the mould shell to obtain a casting;
step 6, processing; and (3) after stress relief annealing is carried out on the casting at 800 ℃, a dead head is cut off, and the size of the casting is finely finished.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111139940.5A CN115870453A (en) | 2021-09-28 | 2021-09-28 | Lost foam casting method of alloy shield |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111139940.5A CN115870453A (en) | 2021-09-28 | 2021-09-28 | Lost foam casting method of alloy shield |
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| CN115870453A true CN115870453A (en) | 2023-03-31 |
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| CN202111139940.5A Pending CN115870453A (en) | 2021-09-28 | 2021-09-28 | Lost foam casting method of alloy shield |
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- 2021-09-28 CN CN202111139940.5A patent/CN115870453A/en active Pending
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