CN116809862B - Clean shell for lost foam casting, preparation method and application thereof - Google Patents
Clean shell for lost foam casting, preparation method and application thereof Download PDFInfo
- Publication number
- CN116809862B CN116809862B CN202310801632.7A CN202310801632A CN116809862B CN 116809862 B CN116809862 B CN 116809862B CN 202310801632 A CN202310801632 A CN 202310801632A CN 116809862 B CN116809862 B CN 116809862B
- Authority
- CN
- China
- Prior art keywords
- coating
- casting
- foam
- layer
- shell
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000010114 lost-foam casting Methods 0.000 title claims abstract description 63
- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 238000000576 coating method Methods 0.000 claims abstract description 88
- 239000006260 foam Substances 0.000 claims abstract description 88
- 239000011248 coating agent Substances 0.000 claims abstract description 87
- 238000005266 casting Methods 0.000 claims abstract description 64
- 238000000034 method Methods 0.000 claims abstract description 34
- 239000011324 bead Substances 0.000 claims abstract description 21
- 238000001035 drying Methods 0.000 claims abstract description 12
- 238000004519 manufacturing process Methods 0.000 claims abstract description 10
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 12
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 10
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical group [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 claims description 9
- 229910052919 magnesium silicate Inorganic materials 0.000 claims description 9
- 235000019792 magnesium silicate Nutrition 0.000 claims description 9
- 239000000391 magnesium silicate Substances 0.000 claims description 9
- 239000003973 paint Substances 0.000 claims description 9
- 238000005187 foaming Methods 0.000 claims description 5
- 238000007599 discharging Methods 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 239000002994 raw material Substances 0.000 claims description 3
- 230000001737 promoting effect Effects 0.000 claims description 2
- 238000009841 combustion method Methods 0.000 abstract description 5
- 238000010304 firing Methods 0.000 description 23
- 238000002485 combustion reaction Methods 0.000 description 13
- 239000007789 gas Substances 0.000 description 11
- 238000002309 gasification Methods 0.000 description 9
- 230000007547 defect Effects 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000004793 Polystyrene Substances 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 5
- 229920002223 polystyrene Polymers 0.000 description 5
- 235000019441 ethanol Nutrition 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 238000005495 investment casting Methods 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000001723 curing Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 238000005984 hydrogenation reaction Methods 0.000 description 2
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- 239000011819 refractory material Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910001339 C alloy Inorganic materials 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000010097 foam moulding Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000005058 metal casting Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920006327 polystyrene foam Polymers 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000006188 syrup Substances 0.000 description 1
- 235000020357 syrup Nutrition 0.000 description 1
Classifications
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C23/00—Tools; Devices not mentioned before for moulding
- B22C23/02—Devices for coating moulds or cores
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention provides a net shell for lost foam casting, a preparation method and application thereof, comprising the following steps: (1) manufacturing a foam pattern: pretreating foam beads, and manufacturing a foam pattern with the same appearance as that of a casting; (2) coating and drying: coating a coating on a foam pattern to prepare a lost foam casting mold, firstly coating an inner layer coating on the outer surface of the foam pattern, drying at normal temperature, and then coating an outer layer coating on the outer surface of the inner layer coating, drying at normal temperature; (3) high-temperature flame layer-by-layer roasting: and (3) roasting the lost foam casting mold layer by layer from the gate position to the bottom of the casting mold by using the high-temperature flame obtained in the step (2), and obtaining the net-shaped shell for lost foam casting after the foam pattern is completely gasified. The method adopts high-temperature flame to bake the casting mould layer by layer to prepare the clean shell for lost foam casting, so that the foam pattern is gasified and discharged at high temperature, and the problem that black carbide remains on the inner surface of the lost foam shell in the combustion method can be avoided.
Description
Technical Field
The invention relates to the technical field of lost foam casting, in particular to a net shell for lost foam casting, a preparation method and application thereof.
Background
The lost foam casting technology invented in 1971 is widely applied to various casting factories by virtue of the advantages of smooth casting surface, high dimensional accuracy, good formability of thin-wall complex castings and almost no need of subsequent machining. However, the lost foam casting technology still has some problems to be solved to date: the casting process is accompanied with the gasification of the foam pattern, which can pollute the environment; the probability of casting air hole defects caused by casting gas production is greatly increased; the foam pattern for the lost foam is mainly gasified and cracked to generate the hydrocarbon, and the nonferrous metal, the low-carbon alloy steel and other materials are very sensitive to the hydrocarbon, so that the defects of carburetion, hydrogen embrittlement and the like of the casting are easily caused to deteriorate the microstructure and mechanical property of the casting. For example, the carburetion effect caused by lost foam casting has been clearly described in non-patent documents such as "current research status of carburetion defect of lost foam casting", initial detection of carburetion law on the surface of medium and low carbon lost foam casting, and "carburetion on the surface of lost foam casting".
Chinese patent CN115740364a discloses a method for preparing lost pattern shells and castings by means of stratified combustion, a pattern shell, comprising the steps of: (1) Coating the surface of the foam mould with a coating, and then drying to completely dehydrate the mould to obtain a casting mould; (2) The casting mould is fixed along the axis and then rotates, and organic combustion improver is poured on the surface of the casting mould from the pouring gate position of the casting mould, so that the organic combustion improver penetrates through the casting mould wall and is attached to the foam surface; (3) And igniting the casting mould from the pouring gate, discharging gas products generated by the combustion and decomposition of the foam in the casting mould to the pouring gate, and obtaining the lost foam hollow shell made of refractory materials after the combustion is completed.
The technical scheme reduces the defects of carburetion, hydrogen increment, air holes, slag inclusion, uneven casting surface and the like caused by the decomposition of polystyrene and the like in molten metal during the traditional lost foam casting. But the following problems still remain: on one hand, when the combustion method is adopted to promote the combustion and decomposition of foam in the casting mold, black carbide inevitably generated after the foam is combusted is left on the inner surface of the lost foam shell, and the black carbide has the typical characteristics of extremely high melting point and difficult decomposition, so that the carbide tends to exist in a casting in the form of inclusion, and meanwhile, the surface of the casting is uneven and the precision is reduced; on the other hand, the technical scheme is difficult to thoroughly avoid the problem of carburetion on the surface of the casting, and if carbide generated by a combustion method is not cleaned, the carburetion on the surface of the subsequent casting still can be caused, so that the quality of the casting workpiece is reduced. In addition, to ensure adequate combustion of the foam, the organic combustion improver needs to coat the entire foam surface inside the mold; meanwhile, the work of removing black carbide after combustion is additionally added, so that the production cost is increased, and the production efficiency is reduced.
Disclosure of Invention
In view of the above, the invention provides a preparation method of a clean shell for lost foam casting by layer-by-layer roasting, so as to solve the technical problems that carbide residues exist after a foam pattern burns in the prior art, and carburetion on the surface of a casting is difficult to thoroughly avoid.
The technical scheme of the invention is realized as follows:
in a first aspect, the invention provides a method for preparing a net shell for lost foam casting, comprising the following steps:
(1) Manufacturing a foam pattern: pretreating foam beads, and manufacturing a foam pattern with the same appearance as that of a casting;
(2) Coating paint and drying: coating a coating on a foam pattern to prepare a lost foam casting mold, firstly coating an inner layer coating on the outer surface of the foam pattern, drying, coating an outer layer coating on the outer surface of the inner layer coating, and drying;
(3) Roasting the raw materials layer by high-temperature flame: and (3) roasting the lost foam casting mould obtained in the step (2) layer by layer from the gate position to the bottom of the casting mould, promoting the foam pattern to gasify at high temperature, discharging gas along the gate, and obtaining the net shell for lost foam casting after the foam pattern is completely gasified.
Specifically, during the baking in the step (3), the paint layer is baked, and the high temperature is transferred to the foam pattern through the paint layer, so that the foam pattern is gasified and discharged. The key reason that the method of the invention does not use the integral roasting method for gasifying the foam pattern is as follows: the method can avoid the problems because a large amount of gas generated at high temperature cannot be discharged in time and can cause the expansion of the casting mould. The reason for selecting the roasting starting point at the pouring gate is that the foam pattern at the pouring gate is communicated with the atmosphere, and the pouring gate can firstly realize foam gasification and then gradually contact with the atmosphere, so that gas exchange between the gas generated by the foam pattern and the atmosphere can be fully realized, and the expansion and breaking of the casting shell are avoided.
On the basis of the above technical solution, preferably, the step (1) of pretreating the foam beads includes: and adding silicate medium with the mass ratio of 2-10% into the foam beads, uniformly mixing, and then foaming, wherein the foam beads are made of one of polyethylene, polystyrene or polypropylene. In the process of roasting the foam layer by layer from the pouring gate to the bottom of the casting mold, the foam is gasified to form a gasification channel for discharging after the subsequent foam is gasified, if the foam in the previous layer is not gasified completely, the gasification channel is blocked, so that a 'closed space' is formed at the back unvaporized part, and after the foam in the 'closed space' is gasified, the foam cannot be discharged through the gasification channel, so that the part is heated and expanded, and the coating or the casting mold is broken. The silicate medium is added into the foam beads, and the silicate medium and the foam beads are foamed in a composite manner to form a porous structure, so that the pores inside the foam beads are filled with air, heat conduction can be promoted, and sufficient gasification of the foam is accelerated, thereby avoiding the problem that the casting shell is broken due to the formation of a closed space in the process of roasting from a pouring gate to the bottom of a casting mold.
Still more preferably, the silicate medium is a magnesium silicate or aluminum silicate medium, and the silicate medium has a particle size of 20 to 2000 mesh. The magnesium silicate and the aluminum silicate have better heat conduction capability, and the particle size of the silicate medium is limited to be favorable for uniform dispersion of the silicate medium in the foam beads, and if the particle size is too large, the particle size distribution is easily uneven, so that the formation of a porous structure is influenced; if the particle size is too small, agglomeration is easy, and dispersion of silicate medium in foam beads is also affected, and finally the heat conduction effect is affected.
On the basis of the technical scheme, the high-temperature flame roasting speed in the step (3) is preferably 16-80 mm/s. In the layer-by-layer roasting process, the too high roasting speed can cause insufficient gasification of a foam pattern and residue; too slow a firing rate can result in excessive firing, which can lead to carbonization and brittle failure of the mold.
On the basis of the technical scheme, preferably, the high-temperature flame roasting temperature in the step (3) is 600-2000 ℃. Too low a firing temperature to reach the critical value of complete foam gasification may result in incomplete foam gasification; too high a firing temperature can result in excessive firing, causing the cast shell to carbonize and brittle fracture.
On the basis of the technical scheme, preferably, in the step (3), the roasting width of each layer is 5-15 mm when roasting layer by layer until roasting to the bottom of the casting mold. Too wide a firing width may result in uneven firing; too narrow roasting width can affect roasting efficiency, and roasting uniformity can be ensured while roasting efficiency is ensured by limiting the roasting width to 5-15 mm.
On the basis of the above technical scheme, preferably, the inner coating in the step (2) is an alcohol-based coating, the outer coating is a water-based coating, and the particle size of the inner coating is smaller than that of the outer coating.
It should be noted that, the inner layer coating and the outer layer coating are coated for 3-5 times respectively, and each coating needs to be dried for enough time to ensure that the last coating is completely dried when the next coating is hung. Wherein the alcohol-based paint comprises 1.5-4% of polyvinyl butyral, 20-25% of quartz powder, 25-30% of graphite powder and the balance of ethanol. The outer coating is selected from one of CMC coating, syrup coating or pulp raffinate coating. By arranging the inner layer coating and the outer layer coating, the rigidity of the foam pattern can be improved, and deformation during embedding operation is prevented; meanwhile, the particle size of the inner layer coating is smaller than that of the outer layer coating, the inner layer adopts fine coating to ensure that the coating can be accurately attached to a foam pattern to improve the precision, and the outer layer adopts coarse coating to ensure that the finally formed shell has certain strength.
Still more preferably, the thickness of the inner coating is 0.5-2 mm, and the thickness of the outer coating is 1-3 mm.
In a second aspect, the invention provides a net-shape shell for lost foam casting, which is prepared by the preparation method of the net-shape shell for lost foam casting.
In a third aspect, the invention provides an application of a net-shaped shell for lost foam casting, and a casting is prepared by adopting the net-shaped shell prepared by the preparation method of the net-shaped shell for lost foam casting. Embedding the clean shell prepared by the method in sand, coating a film, vacuumizing, and pouring molten metal under negative pressure to obtain the casting.
Compared with the prior art, the preparation method of the net shell for lost foam casting has the following beneficial effects:
(1) The method has the advantages that the foam pattern is roasted layer by layer to prepare the clean shell for lost foam casting, so that the foam pattern is gasified and discharged at high temperature, and the problem that black carbide remains on the inner surface of the lost foam shell in a combustion method can be avoided; meanwhile, the pouring gate is taken as a starting point to bake the casting mold bottom layer by layer, so that the gas exchange between the gas generated by the foam pattern and the atmosphere can be fully realized, and the casting mold is prevented from being broken;
(2) The foam beads are pretreated, namely silicate medium is added into the foam beads and is compounded and foamed with the foam beads to form a porous structure, so that the pores inside the foam beads are filled with air, heat conduction can be promoted, and the foam is fully gasified, thereby avoiding the problem of mould expansion and breaking caused by forming a 'closed space' in the process of roasting from a pouring gate to the bottom of a casting mould;
(3) When the traditional lost foam casting is performed, the casting mold containing foam inside is directly subjected to molten metal casting, so that the defects of carburetion, hydrogenation and the like of the casting are caused, and the performance influence on hydrocarbon sensitive castings such as nonferrous metals, low carbon steel and the like is particularly obvious. The invention realizes 'no-mould' casting mould by gasifying the foam pattern through layer-by-layer roasting before casting, thereby eliminating the defects of carburetion, hydrogenation and the like of castings produced by traditional lost foam casting.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a front view of a net-shape shell for lost foam casting prepared in example 1 of the present invention;
FIG. 2 is a top view of the net-shape shell for lost foam casting prepared in example 1 of the present invention;
fig. 3 is a front view of the lost foam casting prepared in comparative example 1 of the present invention;
fig. 4 is a top view of the lost foam casting prepared in comparative example 1 of the present invention.
Detailed Description
The following description of the embodiments of the present invention will clearly and fully describe the technical aspects of the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, are intended to fall within the scope of the present invention.
Example 1
The embodiment provides a preparation method of a net shell for lost foam casting by layer-by-layer roasting, which specifically comprises the following steps:
(1) Manufacturing a foam pattern: adding 6% magnesium silicate medium into the foam beads, mixing uniformly, wherein the particle size of the magnesium silicate is 1000 meshes. And then the pretreated foam beads are subjected to pre-foaming, curing, foaming forming, cooling and demolding, and the combined model cluster is used for preparing a foam pattern with the same appearance as a casting.
(2) Coating paint and drying: and coating a coating on the foam pattern to prepare the lost foam casting mold. Specifically, the inner layer coating is prepared by 3% of polyvinyl butyral, 20% of quartz powder, 30% of graphite powder and 47% of ethanol in a mass ratio. The outer coating is CMC coating. The coating method comprises the following steps: the inner layer coating is uniformly coated on the surface of the foam pattern (except the gate position), and then the outer layer coating is coated outside the inner layer coating. The thickness of the inner layer coating is 0.8mm, and the thickness of the outer layer coating is 1.5mm. The inner layer coating and the outer layer coating are respectively coated for 3 times, and each coating needs to be dried for enough time, and the coating can be dried by an oven, wherein the temperature of the oven is 70 ℃, and the baking time is 12 hours, so that the last coating is completely dried when the coating is hung next time.
(3) Roasting the raw materials layer by high-temperature flame: and (3) roasting the lost foam casting mould obtained in the step (2) layer by layer from the gate position to the bottom of the casting mould, wherein the roasting speed is 50mm/s, the roasting temperature is 1300 ℃, the roasting width of each layer is 10mm, the foam pattern is promoted to be gasified at high temperature, gas is discharged along the gate, and the clean shell for lost foam casting is obtained after the foam pattern is completely gasified.
Example 2
This example provides a method for preparing a net shell for lost foam casting by layer-by-layer firing, which has the same operation steps as those of example 1 except that the magnesium silicate is added in a mass ratio of 2%.
Example 3
The present example provides a method for preparing a net-shaped shell for lost foam casting by layer-by-layer firing, which has the same operation steps as those of example 1, except that the magnesium silicate is added in the step (1) in a mass ratio of 10%.
Example 4
This example provides a method for preparing a net shell for lost foam casting by layer-by-layer firing, which has the same operation steps as those of example 1, except that the magnesium silicate added in step (1) has a particle size of 20 mesh.
Example 5
This example provides a method for preparing a net shell for lost foam casting by layer-by-layer firing, which has the same operation steps as those of example 1, except that the magnesium silicate added in step (1) has a particle size of 2000 mesh.
Example 6
This example provides a method for preparing a net-shaped shell for lost foam casting by layer-by-layer firing, which has the same operation steps as those of example 1, except that the firing rate in step (3) is 16mm/s.
Example 7
This example provides a method for preparing a net-shaped shell for lost foam casting by layer-by-layer firing, which has the same operation steps as those of example 1, except that the firing rate in step (3) is 80mm/s.
Example 8
This example provides a method for preparing a net shell for lost foam casting by layer-by-layer firing, which operates in the same manner as example 1 except that the firing temperature in step (3) is 600 ℃.
Example 9
This example provides a method for preparing a net shell for lost foam casting by layer-by-layer firing, which operates in the same manner as example 1 except that the firing temperature in step (3) is 2000 ℃.
Example 10
This example provides a method for preparing a net-shaped shell for lost foam casting by layer-by-layer firing, which has the same operation steps as those of example 1, except that the firing width of each layer in step (3) is 5mm.
Example 11
This example provides a method for preparing a net-shaped shell for lost foam casting by layer-by-layer firing, which has the same operation steps as those of example 1, except that the firing width of each layer in step (3) is 15mm.
Example 12
This example provides a method for preparing a net-shaped shell for lost foam casting by layer-by-layer calcination, which has the same procedure as in example 1, except that the foam beads are not pretreated in step (1). During roasting, a small amount of foam pattern is incompletely gasified, and blocks a gas exchange channel, so that a net shell is broken.
Comparative example 1
The embodiment discloses a method for preparing a vanishing model shell by adopting a layered combustion method, which specifically comprises the following steps:
step 1, preparing a pattern: preparing a foam pattern with the same appearance as a casting by using polystyrene foam beads through pre-foaming, curing, foam molding, cooling and demolding and combining a model cluster;
step 2, paint configuration: the mass ratio of the special paint for lost foam casting to the pure water is 1: 1. The detailed process is as follows: pouring 500g of water into a stirring vessel, starting a stirrer to slowly add special sand (the adding speed is 500 g/min), increasing the rotating speed of the stirrer (the rotating speed increasing speed is 25 r/s), stopping rotating speed increasing and maintaining the rotating speed when the rotating speed reaches 1600 revolutions, and after the special sand is added, maintaining the original rotating speed for 30 minutes, and finally reducing the rotating speed to 1200 revolutions and stirring for 480 minutes until the paint uniformly presents paste;
step 3, preparing a casting mould: uniformly coating the coating prepared in the step 2 on the surface of the pattern obtained in the step 1 (except for the gate position), wherein the coating times are 3 times, the pattern is required to be dried or the surface coating is not dropped between each two coating times, then setting the working temperature of a drying box to be 70 ℃, and baking the dried pattern for 12 hours to completely dehydrate the pattern;
step 4, combustion preparation: keeping the casting mould obtained in the step 3 rotating, and pouring 10ml of absolute ethyl alcohol from the casting mould pouring gate position to the casting mould bottom direction, wherein the pouring length is about 5-10mm each time, so that the organic combustion improver is immersed into the interior through the shell wall and is adhered to the polystyrene;
step 5, burning the pattern: the polystyrene attached with the organic combustion improver is ignited to burn slowly, and the gas products of combustion decomposition are discharged from the inside of the mold shell to the gate, and the process is gradually advanced to the inside of the mold shell, so that the polystyrene pattern in the mold shell is completely eliminated, and finally only the hollow mold shell made of refractory materials is left.
Preparing lost foam casting castings
The net shells for lost foam casting prepared in examples 1-11 and comparative example are poured with the same amount of molten iron, and cast under the same negative pressure condition to prepare castings. The surface accuracy, roughness and surface residue of each casting were compared. Residual Strength of investment casting shells prepared according to HB5352.1-86 method for measuring flexural Strength of investment casting shells: the residual strength is that the shell is put into a furnace at 300 ℃, gradually heated to 1500 ℃, kept for 2 hours, cooled to below 300 ℃ and taken out of the furnace for detection. See table 1.
TABLE 1
In combination with the net shell pattern of example 1 and comparative example 1, it was found that the shells prepared in the comparative example did not remove the foam completely, and black "scorch foam", i.e., black residue, was found to remain at extremely high temperatures (> 1500 ℃) and the casting temperatures of metals such as common aluminum alloys were far from, and it was found that for such metals "scorch foam" was present throughout the casting process, which would induce numerous defects in the cast that would affect performance, such as inclusions, shrinkage porosity, stress concentrations, and the like. As can be seen from Table 1, the net shell cast castings for lost foam casting prepared in example 1 of the present invention had the highest surface quality, while the investment casting shells prepared in example 1 had the lowest residual strength.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (6)
1. The preparation method of the net shell for lost foam casting is characterized by comprising the following steps of: the method comprises the following steps:
(1) Manufacturing a foam pattern: pretreating foam beads, and manufacturing a foam pattern with the same appearance as that of a casting;
(2) Coating paint and drying: coating a coating on the foam pattern to prepare a lost foam casting mold; coating an inner layer coating on the outer surface of the foam pattern, drying, coating an outer layer coating on the outer surface of the inner layer coating, and drying; the inner layer coating and the outer layer coating are respectively coated for 3-5 times, and each layer of coating needs to be dried for enough time to ensure that the last coating is completely dried when the coating is hung next time;
(3) Roasting the raw materials layer by high-temperature flame: roasting the lost foam casting mould obtained in the step (2) layer by layer from a gate position to the bottom of the casting mould, promoting the foam pattern to gasify at high temperature, discharging gas along the gate, and obtaining a clean shell for lost foam casting after the foam pattern is completely gasified;
the step (1) of pre-treating the foam beads comprises: adding silicate medium with the mass ratio of 2% -10% into the foam beads, uniformly mixing, and then performing foaming treatment;
the high-temperature flame roasting speed in the step (3) is 16-80 mm/s;
the high-temperature flame roasting temperature in the step (3) is 600-2000 ℃;
and (3) when roasting the materials layer by layer in the step (3), the roasting width of each layer is 5-15 mm until the materials are roasted to the bottom of the casting mold.
2. A method for preparing a net-shape shell for lost foam casting as defined in claim 1, wherein: the silicate medium is magnesium silicate or aluminum silicate medium, and the particle size of the silicate medium is 20-2000 meshes.
3. A method for preparing a net-shape shell for lost foam casting as defined in claim 1, wherein: in the step (2), the inner layer coating is an alcohol-based coating, the outer layer coating is a water-based coating, and the particle size of the inner layer coating is smaller than that of the outer layer coating.
4. A method for preparing a net-shape shell for lost foam casting as defined in claim 1, wherein: in the step (2), the thickness of the inner layer coating is 0.5-2 mm, and the thickness of the outer layer coating is 1-3 mm.
5. The utility model provides a net type shell for lost foam casting which characterized in that: is prepared by a method for preparing a net-shaped shell for lost foam casting according to any one of claims 1 to 4.
6. An application of a net shell for lost foam casting, which is characterized in that: a casting prepared by using the net shell prepared by the method for preparing a net shell for lost foam casting according to any one of claims 1 to 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310801632.7A CN116809862B (en) | 2023-07-03 | 2023-07-03 | Clean shell for lost foam casting, preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310801632.7A CN116809862B (en) | 2023-07-03 | 2023-07-03 | Clean shell for lost foam casting, preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116809862A CN116809862A (en) | 2023-09-29 |
| CN116809862B true CN116809862B (en) | 2023-12-29 |
Family
ID=88116284
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310801632.7A Active CN116809862B (en) | 2023-07-03 | 2023-07-03 | Clean shell for lost foam casting, preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116809862B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004074188A (en) * | 2002-08-12 | 2004-03-11 | Punch Industry Co Ltd | Casting pattern, production method used for the same, and casting method using casting pattern |
| CN102672103A (en) * | 2012-05-29 | 2012-09-19 | 刘翔 | Shell casting method through contraction and then gasification of high-performance coating foam and mold sample of evanescent mode |
| JP2015009266A (en) * | 2013-07-01 | 2015-01-19 | 株式会社亀山鋳造所 | Lost foam pattern, material for lost foam pattern, casting process for lost foam pattern |
| CN110355331A (en) * | 2018-08-07 | 2019-10-22 | 辽宁红山玉科技有限公司 | The process for making shell of formwork for hot investment casting |
| CN110479957A (en) * | 2019-07-29 | 2019-11-22 | 山东燕山精密机械有限公司 | Evaporative pattern shell and preparation method thereof |
| CN114888237A (en) * | 2022-05-24 | 2022-08-12 | 河南拓铸实业有限公司 | Preparation method of evaporative pattern shell and application of evaporative pattern shell in pattern casting |
| CN115740364A (en) * | 2022-11-24 | 2023-03-07 | 华中科技大学 | Method for preparing evaporative pattern shell and casting by using stratified combustion method and shell |
-
2023
- 2023-07-03 CN CN202310801632.7A patent/CN116809862B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004074188A (en) * | 2002-08-12 | 2004-03-11 | Punch Industry Co Ltd | Casting pattern, production method used for the same, and casting method using casting pattern |
| CN102672103A (en) * | 2012-05-29 | 2012-09-19 | 刘翔 | Shell casting method through contraction and then gasification of high-performance coating foam and mold sample of evanescent mode |
| JP2015009266A (en) * | 2013-07-01 | 2015-01-19 | 株式会社亀山鋳造所 | Lost foam pattern, material for lost foam pattern, casting process for lost foam pattern |
| CN110355331A (en) * | 2018-08-07 | 2019-10-22 | 辽宁红山玉科技有限公司 | The process for making shell of formwork for hot investment casting |
| CN110479957A (en) * | 2019-07-29 | 2019-11-22 | 山东燕山精密机械有限公司 | Evaporative pattern shell and preparation method thereof |
| CN114888237A (en) * | 2022-05-24 | 2022-08-12 | 河南拓铸实业有限公司 | Preparation method of evaporative pattern shell and application of evaporative pattern shell in pattern casting |
| CN115740364A (en) * | 2022-11-24 | 2023-03-07 | 华中科技大学 | Method for preparing evaporative pattern shell and casting by using stratified combustion method and shell |
Non-Patent Citations (1)
| Title |
|---|
| 薄壁光整消失模壳型铸造的型壳研究;廖德锋等;铸造(第12期);1220-1223 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116809862A (en) | 2023-09-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108907095B (en) | Casting method for rapidly casting large-scale precise casting based on 3D printing technology | |
| CN109759543B (en) | Cast copper sculpture casting production method | |
| CN105127409B (en) | Preheating-free long nozzle capable of being repeatedly used and preparing method thereof | |
| CH618361A5 (en) | ||
| CN102672104A (en) | Precision casting method for pouring evanescent mold through high-performance coating foam and mold laminating paraffin | |
| WO2017114066A1 (en) | Environmentally friendly method for preparing automobile engine shell | |
| WO2017114078A1 (en) | Method for preparing engine component | |
| CN116809862B (en) | Clean shell for lost foam casting, preparation method and application thereof | |
| CN101947648A (en) | Method for producing large zirconium and zirconium alloy casting | |
| CN113102692B (en) | Manufacturing method of vein-proof sand core | |
| CN105537526A (en) | Forming method of flame-retarding insulating riser | |
| CN103084540B (en) | A kind of lost foam paint compound method for casting heat-resistant steel or wear-resisting alloy steel | |
| CN110090917B (en) | Preparation method of cast-infiltration coating and preparation method of cast-infiltration coating | |
| CN115740364A (en) | Method for preparing evaporative pattern shell and casting by using stratified combustion method and shell | |
| US3389743A (en) | Method of making resinous shell molds | |
| CN112250473B (en) | Gradient porous ceramic core and preparation method thereof | |
| Buchilin et al. | Ceramic filters for aluminum melt | |
| CN114985673B (en) | Casting coating with lithium silicate as binder and suitable for sand casting aluminum-lithium alloy | |
| CN117505779A (en) | Manufacturing method and application of shell for investment casting of 3D printing hollow photosensitive resin mold | |
| CN110656256A (en) | Aluminum casting machining process | |
| SU865489A1 (en) | Method of making undetachable ceramic moulds by the investment pattern technique | |
| CN110961575B (en) | Molding method of sand mold | |
| Bhati et al. | Optimization of process parameters of A-359 aluminium alloy in EPS-assisted-investment casting process using Taguchi method | |
| KR101755832B1 (en) | Method of manufacturing precision cast parts for vehicle exhaust system | |
| CN217912723U (en) | Hollow shell casting process mold capable of improving strength of inner hole |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |