CN1281831A - Expanding gypsum casting powder and its paste-making method by using water - Google Patents
Expanding gypsum casting powder and its paste-making method by using water Download PDFInfo
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- CN1281831A CN1281831A CN 00119619 CN00119619A CN1281831A CN 1281831 A CN1281831 A CN 1281831A CN 00119619 CN00119619 CN 00119619 CN 00119619 A CN00119619 A CN 00119619A CN 1281831 A CN1281831 A CN 1281831A
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/14—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
- C04B28/145—Calcium sulfate hemi-hydrate with a specific crystal form
- C04B28/146—Calcium sulfate hemi-hydrate with a specific crystal form alpha-hemihydrate
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- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Mold Materials And Core Materials (AREA)
Abstract
The present invention relates to an expansive gypsum casting powder and method for preparing gypsum paste by mixing with water. The composition of said gypsum casting powder is formed from (wt%) alpha gypsum powder 28%-38%, cristobalite powder 0-29%, silica flour 20%-70%, additive A 0.3-0.8%, additive B 0.8%-1.2% and additive C 0.9%-1.1%, in which the additive A is a kind of organic macromolecular material, for example hydroxyethyl cellulose, modified dextrin and polyvinyl alcohol, the additive B is a kind of inorganic material, for example various silicates, aluminium silicate and calcium aluminate, etc., and the additive C is a gelatination time control agent.
Description
What the present invention relates to is a kind of gypsum casting powder and paste-making method by using water thereof, and particularly a kind of expanded polystyrene veneer gypsum casting powder and paste-making method by using water thereof belong to the foundry field.
Cast powder and paste-making by using water and make gypsum model, the casting powder is the critical material of plaster casting.Because the technology of product object difference, plaster casting has nothing in common with each other, the casting powder also there is different requirements.Ornaments spare is very thin, must as effects such as centrifugal, negative pressure, pressurizations down, make molten metal be full of each tiny position of die cavity in external force during cast.Therefore, gypsum model should support with the high temperature steel metal sleeve, and rate of expansion must quite could guarantee the tight support of steel bushing to gypsum model with high temperature steel when its baking heat.Can determine the major components of expanded polystyrene veneer casting powder on the basis to the analysis of casting powder, be far from being enough but only reach the expansion purpose.During the gypsum model high-temperature roasting, under the effect of various stress (the gasification decomposition of wax expansion, gypsum contraction, refractory materials expansion and some chemical substances etc.), very easily crack, big crackle can cause Lou copper water cast failure, small crackle causes the foundry goods joint flash and scraps, and all is unallowed.Through to literature search, find as yet and the theme one of the present invention closely-related reported in literature of making peace.
The objective of the invention is to overcome deficiency of the prior art, a kind of expanded polystyrene veneer gypsum casting powder and paste-making method by using water thereof are provided.
Technical scheme of the present invention is as follows: set of dispense of the present invention than (massfraction) is: alpha gypsum powder 28%-38%, cristobalite powder 0-29%, silica powder 30%-70%, additive A 0.3%-0.8%, additive B 0.8%-1.2%, addition of C 0.9%-1.1%, wherein additive A is a kind of organic polymer material, for example Natvosol, modification dextrin, polyvinyl alcohol etc.; Additive B is a kind of inorganic materials, for example various silicate, aluminosilicate, calcium aluminate etc.; Addition of C is the gelation time control agent, for example setting accelerator Sodium Silicofluoride, Repone K, hydrochloric acid etc.When compound prepares, should earlier about 1/4 silica powder be expected in the middle of mixing and making with additive A, B, C material earlier, and then add other material mixing together, pack, expansion gypsum casting powder paste-making by using water amount of water is 37～40% of a casting powder, and above-mentioned various additives are necessary for pressed powder, so that pack after mixing with other base mateirals, transport storage safely, when preparation during gypsum slurry, the water-soluble or aquation of these pressed powder additives speed and playing a role.
The base mateiral composition of casting powder also has the refractory materials powder except gesso.The coefficient of thermal expansion of gypsum model depends on that the base mateiral of casting powder is a refractory materials.Quartzy crystal conversion at 573 ℃ is accompanied by significant volume to be changed, and 600 ℃ of coefficient of thermal expansions are about 1.35%, and near the crystal conversion that cristobalite takes place 230 ℃ is followed bigger volume change, 300 ℃ of coefficient of thermal expansions about 1.65%.Aluminium silicon series refractory material can not use because thermal expansion is little.Therefore base-material consists of alpha gypsum powder+silica powder+cristobalite powder.
Adjust the proportioning of base-material,, cooperate the crackle tendency in the time of appropriately can reducing the gypsum model baking heat simultaneously to reach needed coefficient of thermal expansion.The massfraction of general alpha gypsum powder is 25%～50%.
Cristobalite does not have natural resource, and through-stone English forms at high-temperature firing more than 1500 ℃, but various non-crystalline state SiO
2, as the waste material of plant silicate body, quartz glass product etc., all can be under lower temperature, for example 1000～1100 ℃, change into cristobalite, fire cost thereby reduce.
Except base mateiral, also must in the casting powder, add additive, its effect has four aspects:
1. during the gypsum model baking heat, strengthen casting mold, prevent to crack; Gypsum model intensity is reduced, improve collapsibility, be convenient to casting finish.
2. prevent the gypsum slurry bleeding that condenses.This water analysis is between the type wall between gypsum model and the wax-pattern time because wax is solid, this moisture just will be as yet not fully the gypsum die cavity of scleroma arrange and cause the rough mold cavity surface of orange peel shape, cast(ing) surface will form the scabbing of corresponding projection.
3. control time of coagulation.Add setting accelerator or retardant, arranged after making casting powder and water mix stable time of coagulation, reach with convenient operation and stablize the gypsum model quality.
4. under some working conditions in order to reduce cost, reduce and remove fully the cristobalite component, suppress gypsum and shrink by adding certain additive, make the thermal expansion amount of gypsum model reach processing requirement.
Substantive distinguishing features of the present invention and marked improvement, thermal expansion should be suitable with the high temperature steel sleeve when being heated by the made gypsum model of casting powder, and the die cavity flawless.The fine and close no orange peel shape of gypsum die cavity smooth surface is water stain simultaneously.Performance of the present invention is as follows:
Development casting powder
Amount of water (adding water in every 100g casting powder) is: 36-40ml;
Operating time is: 8-15 minute;
Ultimate compression strength (hygrometric state) is: 2.5MPa;
Ultimate compression strength (dry state) is: 8.5 MPa;
Rate of expansion (%) is for 700 ℃: 0.91.
The embodiment of the invention:
Embodiment 1
Component prescription (massfraction) is: alpha gypsum powder 28%, cristobalite powder 14.4%, silica powder 55%, additive A (Natvosol)-0.5%, additive B (urea)-1%, addition of C (Sodium Fluoride)-1.1%.
It is standby that above powder is mixed into the casting powder.Preparation gypsum model slurry: add WH earlier
2O=40% will be cast powder then and evenly be sprinkled in the water, stirs in the vacuum chamber degasification one vacuum breaker and take out and pour in wax tree and the heat-resisting steel bushing one and move into vacuum chamber together, vacuumize degasification one vacuum breaker again and take out and leave standstill.More than operation should be finished in before 1～3 minute of casting powder time of coagulation (operating time).This casting mold is applicable to cast karat gold ornaments.
Embodiment 1 effect:
Cast 18K gold ornaments.After the cast gypsum model placed the quick-fried cleaning of Shui Zhongshui.The gypsum model collapsibility is better, clears up more convenient.The cast(ing) surface of cast is clear, bright and clean.Substantially there are not joint flash, splashings.Blank qualification rate ≈ 97%.
Example 2
Component prescription (massfraction) is: alpha gypsum powder 38%, cristobalite powder 29%, silica powder 30%, additive A (Natvosol) 0.8%, additive B (urea) 1.2%, addition of C (Sodium Fluoride) 1%.
It is standby that above powder is mixed into the casting powder.Preparation gypsum model slurry and the perfusion method of gypsum model and step be with example 1, amount of water WH
2O=40%, gypsum model roasting system is as follows: advance the stove roasting during 200～300 ℃ of furnace temperature.At first be incubated 1h, later on by 100 ℃ every liter/insulation 1h, last 750 ℃ of insulation 1～2h, it is big or small and different to look gypsum model.This gypsum model cast back collapsibility is good, suitable cast gold and karat gold ornaments.
Embodiment 2 effects:
The ornaments of cast 24K gold and AgCu8.4Znl alloy.The gypsum model collapsibility is fine, and cleaning is convenient, does not have the worry that damages product.The cast(ing) surface of cast is clear, bright and clean, does not have joint flash, splashings substantially.Blank qualification rate ≈ 99%.
Embodiment 3
Component prescription (massfraction) is: alpha gypsum powder 28%, silica powder 70%, additive A (modification dextrin)-0.3%, additive B (silicate)-0.8%, addition of C (Sodium Fluoride) 0.9%.
It is standby that above powder is mixed into the casting powder.Preparation gypsum model slurry and the perfusion method of gypsum model and step be with example 1, amount of water WH
2O=37%, gypsum model roasting system is as follows: advance the stove roasting during 200～300 ℃ of furnace temperature.At first be incubated 1h, heat up until 750 ℃ of insulation 1～2h with stove later on, it is big or small and different to look gypsum model.This gypsum model cast back collapsibility is poor slightly, low karat gold ornaments of suitable cast and copper alloy products.
Embodiment 3 effects:
The low karat gold of cast and copper alloy ornaments and artwork.The gypsum model collapsibility is poor slightly, and it is certain manual to still need after the quick-fried cleaning of water, progressively rejects gypsum type material.The cast(ing) surface of cast is clear, bright and clean.If some local joint flashes of surface, splashings etc. can not be repaired on the decorative pattern complex surfaces, do not influence casting quality, the blank qualification rate is generally 95%～99%.
Casting powder amount of water should be when gypsum model prepared: 35%～45%, and be 45% as embodiment 1; Embodiment 2 is 40%; Embodiment 3 is 35%.Example 1 is used to pour into a mould the karat gold ornaments; Example 2 is used to pour into a mould karat gold and gold ornament; Example 3 is used to pour into a mould copper alloy products and low karat gold goods.Above-mentioned various additive is necessary for pressed powder, so that pack after mixing with other base mateirals, transports storage safely.When preparation during gypsum slurry, the water-soluble or aquation of these pressed powder additives speed and playing a role.Silica powder and cristobalite powder granularity are as follows: particle diameter＜40 μ m should account for 70%～80% (quality dispersion); Particle diameter 0.053～0.105mm should account for 1%～3% (massfraction); Surplus is between the two.When compound prepares, should earlier about 1/4 silica powder be expected in the middle of mixing and making with A, B, C material earlier, and then add other material mixing together, pack, forbid to make moist.
Claims (3)
1, a kind of expanded polystyrene veneer gypsum casting powder and paste-making method by using water thereof, mainly comprise terra alba, cristobalite powder, silica powder and addition of C, it is characterized in that alpha gypsum powder 28%-38%, cristobalite powder 0-29%, silica powder 30%-70%, additive A 0.3%-0.8%, additive B 0.8%-1.2%, addition of C 0.9%-1.1%, wherein additive A is a kind of organic polymer material, for example Natvosol, modification dextrin, polyvinyl alcohol etc.; Additive B is a kind of inorganic materials, for example various silicate, aluminosilicate, calcium aluminate etc.
2, this expanded polystyrene veneer gypsum casting powder according to claim 1 and paste-making method by using water thereof, its feature are that also silica powder and cristobalite powder granularity are as follows: particle diameter＜40 μ m should account for 70%～80% (quality dispersion); Particle diameter 0.053～0.105mm should account for 1%～3% (massfraction); Surplus is between the two.
3, this expanded polystyrene veneer gypsum casting powder according to claim 1 and paste-making method by using water thereof, its feature is also when compound prepares, should earlier about 1/4 silica powder be expected in the middle of mixing and making with additive A, B, C material earlier, and then add other material mixing together, pack, expansion gypsum casting powder paste-making by using water amount of water is 37%～40% of a casting powder, and above-mentioned various additives are necessary for pressed powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001196197A CN1137793C (en) | 2000-08-17 | 2000-08-17 | Expanding gypsum casting powder and its paste-making method by using water |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001196197A CN1137793C (en) | 2000-08-17 | 2000-08-17 | Expanding gypsum casting powder and its paste-making method by using water |
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| Publication Number | Publication Date |
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| CN1281831A true CN1281831A (en) | 2001-01-31 |
| CN1137793C CN1137793C (en) | 2004-02-11 |
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| CNB001196197A Expired - Fee Related CN1137793C (en) | 2000-08-17 | 2000-08-17 | Expanding gypsum casting powder and its paste-making method by using water |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101804442A (en) * | 2010-04-28 | 2010-08-18 | 贾传新 | Precise investment casting powder and investment casting and moulding process thereof |
| CN101948290A (en) * | 2010-09-08 | 2011-01-19 | 山东金信新型建材有限公司 | Shoe mould casting gypsum powder |
| CN102397980A (en) * | 2011-10-24 | 2012-04-04 | 华中科技大学 | Gypsum mold formula for casting magnesium alloy and preparation method thereof |
| CN103111585A (en) * | 2013-02-04 | 2013-05-22 | 中国兵器工业第五九研究所 | Method for preparing ceramic gypsum composite mould by using magnesium alloy |
| CN104350024A (en) * | 2012-05-30 | 2015-02-11 | 圣戈班普拉科公司 | Gypsum composition for refractory moulds |
| CN104773991A (en) * | 2015-03-27 | 2015-07-15 | 武汉理工大学 | Reinforced anti-cracking mold material and molding method thereof |
| CN105073298A (en) * | 2013-01-04 | 2015-11-18 | S&B工业矿石有限公司 | Method for the production of core sand and/or molding sand for casting purposes |
| CN113811405A (en) * | 2019-03-29 | 2021-12-17 | 古德温公开有限公司 | Investment powder |
-
2000
- 2000-08-17 CN CNB001196197A patent/CN1137793C/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101804442A (en) * | 2010-04-28 | 2010-08-18 | 贾传新 | Precise investment casting powder and investment casting and moulding process thereof |
| CN101804442B (en) * | 2010-04-28 | 2012-01-11 | 贾传新 | Precise investment casting powder and investment casting and moulding process thereof |
| CN101948290A (en) * | 2010-09-08 | 2011-01-19 | 山东金信新型建材有限公司 | Shoe mould casting gypsum powder |
| CN102397980A (en) * | 2011-10-24 | 2012-04-04 | 华中科技大学 | Gypsum mold formula for casting magnesium alloy and preparation method thereof |
| CN104350024A (en) * | 2012-05-30 | 2015-02-11 | 圣戈班普拉科公司 | Gypsum composition for refractory moulds |
| CN105073298A (en) * | 2013-01-04 | 2015-11-18 | S&B工业矿石有限公司 | Method for the production of core sand and/or molding sand for casting purposes |
| CN103111585A (en) * | 2013-02-04 | 2013-05-22 | 中国兵器工业第五九研究所 | Method for preparing ceramic gypsum composite mould by using magnesium alloy |
| CN103111585B (en) * | 2013-02-04 | 2017-12-29 | 中国兵器工业第五九研究所 | A kind of preparation technology of magnesium alloy cast ceramics gypsum composite mould |
| CN104773991A (en) * | 2015-03-27 | 2015-07-15 | 武汉理工大学 | Reinforced anti-cracking mold material and molding method thereof |
| CN113811405A (en) * | 2019-03-29 | 2021-12-17 | 古德温公开有限公司 | Investment powder |
| CN113811405B (en) * | 2019-03-29 | 2024-02-27 | 鼓德温公开有限公司 | Investment powder |
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| Publication number | Publication date |
|---|---|
| CN1137793C (en) | 2004-02-11 |
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