CN110961575A - Molding method of sand mold - Google Patents
Molding method of sand mold Download PDFInfo
- Publication number
- CN110961575A CN110961575A CN201911290458.4A CN201911290458A CN110961575A CN 110961575 A CN110961575 A CN 110961575A CN 201911290458 A CN201911290458 A CN 201911290458A CN 110961575 A CN110961575 A CN 110961575A
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- Prior art keywords
- sand mold
- sand
- mold
- binder
- water glass
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Classifications
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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
-
- 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
- B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
- B22C1/18—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of inorganic agents
- B22C1/186—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of inorganic agents contaming ammonium or metal silicates, silica sols
- B22C1/188—Alkali metal silicates
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/12—Treating moulds or cores, e.g. drying, hardening
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Mold Materials And Core Materials (AREA)
Abstract
The invention discloses a molding method of a sand mold, which comprises the following steps: drying the sand mold material, and uniformly mixing the sand mold material with the binder; manufacturing a mould according to a part drawing; placing the uniformly mixed sand mold and binder into a lower mold and an upper mold of a mold, then placing the mud core into the mold, and closing the mold; introducing carbon dioxide gas into the matched die to solidify the binder to obtain a sand mold blank; carrying out flame smoking on the inner surface of the sand mold blank to obtain a sintered sand mold; the sintered sand mold is subjected to heat treatment at 230-270 ℃ for 80-150 seconds to obtain the sand mold, the defects in the prior art are overcome, sodium aliphatate and gelatin modified sodium silicate are used as a binder, the collapsibility of the sodium silicate is improved, the problems that the used sand mold material is caked, high in strength and incapable of being recycled are solved, and in addition, the sand mold produced by the method has almost no residual molding sand on the surface of a cast after pouring, so that the surface of the cast is ensured to be clean, and the subsequent processing treatment is facilitated.
Description
Technical Field
The invention relates to the technical field of sand molds, and particularly belongs to a molding method of a sand mold.
Background
The sand mould is adopted to produce castings, which is a main production mode of industrial casting production, in order to avoid environmental pollution, the sand mould is mostly manufactured by taking water glass as a binder, the water glass has the advantages of no irritation, no toxicity and low price, but a large amount of sand mould materials can be remained on the surface of the castings after sand mould pouring, so that the subsequent cleaning work on the castings is complicated, and larger smoke dust is generated during cleaning, which is not beneficial to the health of workers.
Disclosure of Invention
The invention aims to provide a molding method of a sand mold, which solves the problem that a large amount of sand mold materials are left on the surface of a casting in the prior art.
In order to solve the problems, the technical scheme adopted by the invention is as follows:
a molding method of a sand mold comprises the following steps:
(1) drying the sand mold material, and uniformly mixing the sand mold material with the binder;
(2) manufacturing a mould according to a part drawing;
(3) placing the uniformly mixed sand mold and binder into a lower mold and an upper mold of a mold, then placing the mud core into the mold, and closing the mold;
(4) introducing carbon dioxide gas into the matched die to solidify the binder to obtain a sand mold blank;
(5) carrying out flame smoking on the inner surface of the sand mold blank to obtain a sintered sand mold;
(6) and carrying out heat treatment on the sintered sand mold at 230-270 ℃ for 80-150s to obtain the sand mold.
Further, the sand mold material is dried by adopting an airflow dryer, and the drying temperature is 80 ℃.
Furthermore, the molding sand material comprises one or more of silica sand and Baozhu sand, and the particle size range of the molding sand material is 100-200 meshes.
Further, the binder comprises 80-90 parts by mass of modified water glass and 3-5 parts by mass of sodium fatty acid.
Further, the modified water glass is gelatin modified water glass.
Further, the modification method of the gelatin modified water glass comprises the following steps: and 3-8 parts of gelatin are dissolved in 40-50 parts of 60 ℃ water glass, and the modified gelatin modified water glass is obtained after cooling.
Further, the density of the water glass is 1.35-1.45g/cm3。
Further, the addition amount of the binder is 2-4% of the mass percent of the sand mold material.
Further, the flame smoking is carried out by burning liquid paraffin with open fire until the inner surface of the sand mold blank is blackened.
Furthermore, the forming layer thickness of the sand mould blank is 5mm-15 mm.
The inner surface of the sand mold is smoked by adopting open fire of liquid paraffin, and a layer of carbon residue is formed on the inner surface of the sand mold due to insufficient combustion of the liquid paraffin, so that the inner surface of the sand mold is smoother, and a casting is isolated from the sand mold in the casting process by the carbon residue, so that the surface of the casting is clean and has no residue of sand mold materials.
Compared with the prior art, the invention has the following implementation effects: the sodium aliphatate and gelatin modified sodium silicate is used as the binder, so that collapsibility of the sodium silicate is improved, the problems that the used sand material is caked, high in strength and incapable of being recycled are solved, and the sand mold produced by the method has almost no residual molding sand on the surface of a cast after pouring, so that cleanness of the surface of the cast is ensured, and subsequent processing treatment is facilitated.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the following 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 derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The density of the water glass used in the invention is 1.35-1.45g/cm3。
Example 1
The molding method of the sand mold comprises the following steps:
(1) drying a sand mold material with the particle size range of 100-200 meshes by using an airflow dryer, wherein the drying temperature is 80 ℃, the molding sand material is silica sand, then uniformly mixing the dried sand mold material with a binder, the adding amount of the binder is 4% of the mass percent of the sand mold material, and the binder comprises 90 parts by mass of modified water glass and 5 parts by mass of sodium aliphatate.
The modified water glass is gelatin modified water glass, and the modification method of the gelatin modified water glass comprises the following steps: and 3 parts of gelatin are dissolved in 50 parts of 60 ℃ water glass, and the modified gelatin modified water glass is obtained after cooling.
(2) Manufacturing a mould according to a part drawing;
(3) placing the uniformly mixed sand mold and binder into a lower mold and an upper mold of a mold, then placing the mud core into the mold, and closing the mold;
(4) introducing carbon dioxide gas into the die after die assembly to cure the binder, wherein the flow rate of the carbon dioxide gas is 1.2m3H, curing for 150s to obtain a sand mold blank, wherein the forming layer thickness of the sand mold blank is 5-7 mm;
(5) carrying out flame smoking on the inner surface of the sand mold blank, wherein the flame smoking adopts open fire smoking of liquid paraffin combustion until the inner surface of the sand mold blank is blackened to obtain a sintered sand mold;
(6) and (4) carrying out heat treatment on the sintered sand mold for 80s at 230 ℃ to obtain the sand mold.
In the obtained sand mold
Example 2
The molding method of the sand mold comprises the following steps:
(1) drying a sand mold material with the particle size range of 100-200 meshes by using an airflow dryer, wherein the drying temperature is 80 ℃, the molding sand material is a mixture of silica sand and jewel sand, then uniformly mixing the dried sand mold material with a binder, the adding amount of the binder is 2% of the mass percent of the sand mold material, and the binder comprises 80 parts of modified water glass and 3 parts of sodium aliphatate.
The modified water glass is gelatin modified water glass, and the modification method of the gelatin modified water glass comprises the following steps: dissolving 8 parts of gelatin in 40 parts of 60 ℃ water glass, wherein the density of the water glass is 1.35-1.45g/cm3And cooling to obtain the modified gelatin modified water glass.
(2) Manufacturing a mould according to a part drawing;
(3) placing the uniformly mixed sand mold and binder into a lower mold and an upper mold of a mold, then placing the mud core into the mold, and closing the mold;
(4) introducing carbon dioxide gas into the die after die assembly to cure the binder, wherein the flow rate of the carbon dioxide gas is 1.2m3H, curing for 120s to obtain a sand mold blank, wherein the forming layer thickness of the sand mold blank is 12-15 mm;
(5) carrying out flame smoking on the inner surface of the sand mold blank, wherein the flame smoking adopts open fire smoking of liquid paraffin combustion until the inner surface of the sand mold blank is blackened to obtain a sintered sand mold;
(6) and carrying out heat treatment on the sintered sand mold at 270 ℃ for 110s to obtain the sand mold.
Example 3
The molding method of the sand mold comprises the following steps:
(1) drying a sand mold material with the particle size range of 100-200 meshes by using an airflow dryer, wherein the drying temperature is 80 ℃, the molding sand material is silica sand, then uniformly mixing the dried sand mold material with a binder, the adding amount of the binder is 3% of the mass percent of the sand mold material, and the binder comprises 90 parts by mass of modified water glass and 4 parts by mass of sodium aliphatate.
The modified water glass is gelatin modified water glass, and the modification method of the gelatin modified water glass comprises the following steps: dissolving 4 parts of gelatin in 50 parts of 60 ℃ water glass with the density of 1.35-1.45g/cm3And cooling to obtain the modified gelatin modified water glass.
(2) Manufacturing a mould according to a part drawing;
(3) placing the uniformly mixed sand mold and binder into a lower mold and an upper mold of a mold, then placing the mud core into the mold, and closing the mold;
(4) introducing carbon dioxide gas into the die after die assembly to cure the binder, wherein the flow rate of the carbon dioxide gas is 1.2m3H, curing for 150s to obtain a sand mold blank, wherein the forming layer thickness of the sand mold blank is 8-10 mm;
(5) carrying out flame smoking on the inner surface of the sand mold blank, wherein the flame smoking adopts open fire smoking of liquid paraffin combustion until the inner surface of the sand mold blank is blackened to obtain a sintered sand mold;
(6) and (4) carrying out heat treatment on the sintered sand mold for 150s at 240 ℃ to obtain the sand mold.
Comparative example 1
The difference from example 3 is that the binder is water glass and the inner surface of the sand mold blank is not subjected to flame roasting.
Comparative example 2
The difference from the example 3 is that the binder is water glass, and the inner surface of the sand mold blank is subjected to flame smoking.
Comparative example 3
The difference from example 3 is that the binder is water glass and sodium aliphatate, and the inner surface of the sand mold blank is subjected to flame roasting.
Comparative example 4
The difference from example 3 is that the binders are modified sodium silicate and sodium aliphatate, and the inner surface of the sand mold blank is not subjected to flame roasting.
Molten steel was poured into the sand molds obtained in examples 1 to 3 and comparative examples 1 to 4, and after cooling, the sand molds were hit with a hammer to crush the sand molds and take out the castings, and the sand molds remaining on the surfaces of the castings were observed, and it was found that the castings produced using the sand molds of examples 1 to 3 and comparative examples 2 and 3 had almost no remaining sand mold material on the surfaces, that the castings produced using the sand mold of comparative example 1 had more remaining sand mold material on the surfaces than the castings produced using the sand mold of comparative example 4, and that the sand molds of comparative examples 1 and 2 were seriously lumpy. According to the invention, the internal surface of the sand mold is smoked by adopting the open fire of the liquid paraffin, and as the liquid paraffin is not combusted sufficiently, a layer of residual carbon is formed on the internal surface of the sand mold, and the internal surface of the sand mold is smoother, and the residual carbon isolates the casting from the sand mold in the casting process, so that the surface of the casting is smooth and has no residue of sand mold materials. The subsequent casting surface cleaning work is simplified.
The strength of the sand molds obtained in examples 1 to 3 and comparative examples 1 to 4 was measured according to GB2684-81 test methods for raw foundry sand and mix materials, and the results are shown in the following table:
| collapsibility resistance to compression (MPa) | |
| Example 1 | 0.43 |
| Example 2 | 0.44 |
| Example 3 | 0.41 |
| Comparative example 1 | 0.57 |
| Comparative example 2 | 0.55 |
| Comparative example 3 | 0.48 |
| Comparative example 4 | 0.43 |
The invention uses sodium aliphatate and water glass modified by gelatin as the binder, when the water glass is solidified, the matrix contains gelatin particles, so that the interior of the water glass is in a discontinuous state after being solidified, thereby improving the bursting property of the water glass, and after the gelatin modified water glass is mixed with the sodium aliphatate as the binder and is mixed with silica sand, the sodium aliphatate has the lubricating effect, so that after the silica sand and the water glass are mixed and solidified, after molten steel is cast, the gelatin and the sodium aliphatate are decomposed by heat absorption, a ceramic phase can not be formed in a sand mould, thereby avoiding the problems that the used sand mould material is agglomerated, has high strength and can not be recycled.
The invention not only improves the collapsibility of the sand mould, but also avoids the caking problem of the sand mould during the molten steel casting, so that the sand mould material can be recycled.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. A molding method of a sand mold is characterized by comprising the following steps:
(1) drying the sand mold material, and uniformly mixing the sand mold material with the binder;
(2) manufacturing a mould according to a part drawing;
(3) placing the uniformly mixed sand mold and binder into a lower mold and an upper mold of a mold, then placing the mud core into the mold, and closing the mold;
(4) introducing carbon dioxide gas into the matched die to solidify the binder to obtain a sand mold blank;
(5) carrying out flame smoking on the inner surface of the sand mold blank to obtain a sintered sand mold;
(6) and carrying out heat treatment on the sintered sand mold at 230-270 ℃ for 80-150s to obtain the sand mold.
2. A method for molding a sand mold according to claim 1, wherein said drying of the sand mold material is performed by an air dryer at a drying temperature of 80 ℃.
3. A method as claimed in claim 1, wherein said sand material comprises one or more of silica sand and baozhu sand, and said sand material has a particle size in the range of 100-200 mesh.
4. A molding method of a sand mold according to claim 1, wherein the binder comprises 80 to 90 parts by mass of modified water glass and 3 to 5 parts by mass of sodium aliphatate.
5. A method of moulding a sand mould according to claim 4, wherein said modified water glass is gelatin modified water glass.
6. A molding method of a sand mold according to claim 5, wherein the method for modifying gelatin-modified water glass comprises: and 3-8 parts of gelatin are dissolved in 40-50 parts of 60 ℃ water glass, and the modified gelatin modified water glass is obtained after cooling.
7. A sand mold molding method according to claim 6, wherein the density of said water glass is 1.35 to 1.45g/cm3。
8. A molding method of a sand mold according to claim 1, wherein the addition amount of the binder is 2-4% of the mass percentage of the sand mold material.
9. A molding method of a sand mold according to claim 1, wherein said flame-baking is performed by open flame-baking in which liquid paraffin is burned until the inner surface of the sand mold blank is blackened.
10. A molding method of a sand mold according to claim 1, wherein a molding layer thickness of said sand mold blank is 5mm to 15 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911290458.4A CN110961575B (en) | 2019-12-16 | 2019-12-16 | Molding method of sand mold |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911290458.4A CN110961575B (en) | 2019-12-16 | 2019-12-16 | Molding method of sand mold |
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| CN110961575A true CN110961575A (en) | 2020-04-07 |
| CN110961575B CN110961575B (en) | 2021-07-13 |
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