CN108380815B - Lost foam casting hardening hollow shell coating and preparation method thereof - Google Patents
Lost foam casting hardening hollow shell coating and preparation method thereof Download PDFInfo
- Publication number
- CN108380815B CN108380815B CN201810510387.3A CN201810510387A CN108380815B CN 108380815 B CN108380815 B CN 108380815B CN 201810510387 A CN201810510387 A CN 201810510387A CN 108380815 B CN108380815 B CN 108380815B
- Authority
- CN
- China
- Prior art keywords
- mesh
- coating
- powder
- accounts
- mass fraction
- 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
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
Abstract
Lost foam casting hardening hollow shell coating and a preparation method thereof, belonging to the technical field of casting coating. The method is characterized in that 50-55% of quartz powder, 10-12% of mica powder, 5-6% of expanded perlite powder and 30-33% of sintered mullite powder are adopted as refractory aggregates by mass, other additives are added, the raw materials are firstly and secondly mixed in a roller type sand mixer in a dry and wet mode to obtain a paste-like coating, then the paste-like coating is put into a stirrer, and water is added for stirring to obtain a liquid coating.
Description
Technical Field
The invention discloses a lost foam casting coating and a preparation method thereof, in particular relates to a lost foam casting hardening hollow shell coating and a preparation method thereof, and belongs to the technical field of casting coatings.
Background
Lost foam casting, also called solid casting, is a casting method in which foam models with similar size and shape to a casting are bonded to form a model cluster, the model cluster is coated with refractory paint and dried, then the model cluster is buried in dry sand for vibration modeling, the model is poured under negative pressure to gasify the model, liquid metal occupies the position of the model, and the model is formed after solidification and cooling. The coating is coated on the surface of an EPS foam model and is required to have the characteristics of high strength, high air permeability, easy falling off from the surface of a casting and the like. The binder in the coating plays an important role, the inorganic binder can maintain the strength at normal temperature and high temperature, the organic binder can improve the strength and rigidity of the coating at normal temperature so as to prevent a pattern from being damaged and deformed when sand filling vibration occurs, so as to ensure the surface quality of a casting, and the coating is burned out and decomposed at a high-temperature pouring state so as to effectively improve the high-temperature air permeability of the coating. The coating is an important consumable material in the lost foam casting production, and the quality of the coating has very important influence on the quality of a casting.
In order to improve the performance of the lost foam casting coating, the chinese invention patent CN107497992 discloses a lost foam casting coating, its preparation method and use method, the lost foam casting coating comprises the following components in parts by weight: 68-78 parts of refractory aggregate, 2-6 parts of hydroxyethyl cellulose, 3-6 parts of nano bentonite, 4-7 parts of syrup, 2-6 parts of white latex and 2-5 parts of flake graphite powder. The lost foam casting coating is characterized by high strength and good stripping property by reasonably proportioning various raw materials in parts by weight. Chinese invention patent CN107214294 also discloses a lost foam casting coating, specifically a high-strength high-adhesion lost foam casting coating: the components by weight portion are as follows: 30-40 parts of bauxite, 30-40 parts of zircon sand powder, 20-30 parts of quartz powder, 1-3 parts of lithium haxate, 2-4.5 parts of polyvinyl butyral, 1-2 parts of acrylate resin, 1-3 parts of phenolic resin, 1-5 parts of silica sol, 1-3 parts of sodium bentonite, 0.1-0.5 part of isopropanol and CMC: 0.5-2 parts, JFC: 0.1-0.5 part; preparation: adding the coating powder and water at a ratio of 1: 0.6-0.8 into a stirrer, stirring for 1-1.5 hr, measuring Baume degree, adjusting Baume degree to 65-70 by adding water, stirring for 15-25 min, and discharging; the invention has excellent performance: good suspension property, thixotropy, air permeability, higher surface strength and high adhesion, environmental protection and low cost. The Chinese patent CN106825389 also discloses a lost foam casting coating, which comprises the following components in parts by weight: 50-60 parts of quartz powder, 1-2 parts of plant rubber powder, 10-15 parts of kaolin, 6-8 parts of bentonite, 4-6 parts of methyl methacrylate, 1-2 parts of neoprene latex and 0.2-0.4 part of catalyst. The evaporative pattern casting coating with the structure has the advantages of good adhesive force, good coating property and good leveling property. The Chinese invention patent CN106694798 also discloses a powdery lost foam casting coating and a use method thereof, wherein the powdery coating comprises the following components in percentage by weight: 88.9 to 89.7 percent of refractory aggregate, 3.7 to 4.5 percent of sodium bentonite, 0.78 to 1.23 percent of polyvinyl alcohol, 0.82 to 1.85 percent of aluminum dihydrogen phosphate, 0.32 to 0.44 percent of sodium carboxymethyl cellulose and 3.8 to 4.8 percent of expanded graphite. When in preparation, all the powder materials are added into a stirrer to be dry-mixed uniformly to obtain the finished product of the powdery lost foam casting coating. When the coating agent is used, water accounting for 23.5-37 wt% of the powdery coating is added into the stirrer, the stirrer is started, the powdery coating is slowly added into the stirrer, and the stirring is continued for 1-2 hours after the addition of the powdery coating is finished, so that the coating agent can be used for coating a lost foam. The raw materials of the invention can achieve the effect of long-time preservation without deterioration without adding formaldehyde, the raw materials do not need to add a surfactant, the trouble of defoaming by adding a defoaming agent in the subsequent use is avoided, the finished product has high strength at normal temperature or high temperature, the coating has good air permeability, and toxic substances can not be released. The Chinese invention patent CN105983646 also discloses a lost foam casting coating which is characterized by comprising 40-50 parts of bauxite, 20-30 parts of zircon powder, 15-20 parts of kaolin, 10-15 parts of corundum powder, 8-12 parts of bentonite, 7-10 parts of water glass, 4-5 parts of silica sol, 2-3 parts of polyvinyl acetate emulsion and 1-2 parts of aluminum sulfate by weight. The coating has the advantages of wide raw material source, low production cost, good temperature resistance, smooth casting surface, no cold shut and no sand adhesion. The invention Chinese patent CN105458160 also discloses a preparation method of the lost foam casting coating, which comprises the following steps: s1: adding a proper amount of water into the common coating, placing the common coating in a coating bucket, and stirring for 40-90min by using a stirrer; s2: measuring the coating specific gravity by using a baume meter; s3: soaking CMC 24 hours in advance; s4: pouring the white latex, the soaked CMC and a proper amount of water into a coating bucket, and uniformly stirring by using a high-speed stirrer; s5: slowly adding quartz powder into a coating bucket, and uniformly stirring by using a high-speed stirrer; s6: adding the lithium bentonite into a coating bucket, and stirring for 40-60min by using a high-speed stirrer; compared with other coatings, the invention simplifies the production process steps, effectively improves the strength of the coating, and reduces the defects of casting skin inclusion, slag inclusion, sand adhesion and the like caused by the fact that the coating layer of the foam model is easy to fall off in the molten iron pouring process to form a coating skin. The Chinese invention patent CN104226893 also discloses a lost foam casting coating and a preparation method thereof. The coating is prepared from mica powder, quartz powder, silica sol, water, vegetable oil, alum, calcium carbonate, n-butanol, rosin and alkyl benzene sulfonic acid; and the mica powder, the quartz powder and the calcium carbonate are sieved by a 300-mesh sieve. The preparation method of the coating comprises the following steps: putting rosin in n-butyl alcohol, slowly heating to 40-50 ℃, adding calcium carbonate after the rosin is completely dissolved to obtain a solution A, fully mixing mica powder, quartz powder and silica sol to obtain a suspension B, dissolving alkylbenzene sulfonic acid in water to obtain a solution C, fully mixing the solution A and the suspension B, adding the solution C, and finally adding alum to mix to obtain the lost foam casting coating. The lost foam casting coating disclosed by the invention is wide in raw material source, low in production cost and simple in preparation method, and the obtained casting is smooth in surface and free of sand sticking. The invention Chinese patent No. 103286259 also discloses a cristobalite lost foam casting coating, which is prepared from cristobalite, graphite, bentonite, organic binder and additive, and is characterized in that the cristobalite 10-90, graphite 5-90, bentonite 1.5-3.0, organic binder 2.0-4.0 and additive 1.0-2.0 are weighed according to the weight components, then water is added, the mixture is mixed and stirred into paste, and the Baume degree is 22-33 Be'. The invention has the advantages that: the air permeability is good, the suspension is good, the volume expansion change is small after the coating is poured, the surface of the casting is smooth, the coating can be automatically peeled, the cost is saved, the process is simple, and the yield of the casting is improved.
When a casting is produced by common lost foam casting, the foam model is not completely liquefied and combusted, so that air holes are easy to appear in the casting, slag is easy to appear on the surface of the casting, and the internal quality and the surface appearance quality of the casting are seriously influenced. In order to overcome the defect of the lost foam casting, researchers successfully develop a first-burning and later-pouring technology of the lost foam casting. The Chinese patent CN105598369 discloses a method for producing ceramic particle reinforced bimetal-based hammerhead by a lost foam, and the production and preparation process comprises the following steps: manufacturing a hammer mould, placing a ceramic prefabricated block, coating, adhering the hammer mould in a box, directionally solidifying with the head facing downwards, sintering in vacuum under negative pressure and then pouring, carrying out vibration pouring forming, and reprocessing the hammer to obtain a finished product. The hammer produced by the method has no parting surface and regular appearance, and waste products caused by box staggering and box expansion are reduced; the hammerhead has high dimensional accuracy, reduces the grinding amount, reduces the labor intensity and reduces the metal loss; and the hammerhead has good wear resistance, long service life and more practicability. The Chinese patent CN105598367 also discloses a method for producing a bimetal composite hammer head by using a lost foam vacuum negative pressure head downwards, and the production and preparation process comprises the following steps: manufacturing a hammer head system model, coating materials, manufacturing a lost foam three-dimensional multi-piece combined mould in a box, directionally solidifying with the head downwards, sintering in vacuum under negative pressure and then pouring, carrying out vibration pouring forming, and reprocessing the hammer head to obtain a finished product. The invention solves the problems that the prior hammer head has low production process efficiency, is difficult to recycle sand and can not realize directional solidification on the working surface of the hammer head. The Chinese patent CN105598419 also discloses a combined casting process for producing a hammer head by using the lost foam, and the production and preparation process comprises the following steps: manufacturing a hammerhead system model, coating materials, manufacturing a lost foam three-dimensional multi-piece combined mould in a box, directionally solidifying with the head downward, sintering under vacuum negative pressure firstly and then pouring, carrying out vibration pouring forming, and reprocessing a hammerhead casting blank to obtain a finished product. The invention uses a plurality of combinations of the lost foam to be stringed together and a plurality of pieces to be stringed and cast, adopts the method of vacuum negative pressure, firstly burning and then casting, and vibrating and casting, so that the produced hammer has smooth appearance, no parting surface, higher wear resistance and safety reliability. However, various lost foam casting coatings developed at present generally have low strength, and cannot realize safe pouring of a hardened hollow shell in the first-burning later-pouring process of lost foam casting.
Disclosure of Invention
The invention aims to realize the great improvement of the strength of the heated coating by changing the composition and the preparation method of the coating, ensure that the evaporative pattern casting can adopt a first-burning later-pouring process to realize the hardening hollow shell pouring, and further greatly improve the casting quality. The evaporative pattern casting hardening hollow shell coating and the preparation method thereof can be realized by the following process steps:
①, quartz powder with the mass fraction of 50-55%, mica powder with the mass fraction of 10-12%, expanded perlite powder with the mass fraction of 5-6% and sintered mullite powder with the mass fraction of 30-33% are taken as refractory aggregate, wherein 160-mesh of 120-mesh accounts for 40%, 220-mesh of 180-mesh accounts for 35%, 270-mesh of 230-mesh accounts for 20%, 320-mesh of 280-mesh accounts for 5%, 220-mesh of 160-mesh of 240-mesh accounts for 70%, 280-mesh of 240-mesh accounts for 30% in the mica powder, 220-mesh of 160-mesh accounts for 45%, 280-mesh of 240-mesh accounts for 55%, 160-mesh of 120-mesh accounts for 35%, 220-mesh of 180-mesh accounts for 45%, 270-mesh of 230-mesh accounts for 12%, and 320-mesh of 280-mesh accounts for 8% in the expanded perlite powder, firstly, the quartz powder with the mass fraction of 50-55%, the magnesium powder with the mass fraction of 10-12%, the magnesium powder with the mass fraction of 5-6%, the sintered mullite powder and the sintered mullite powder are added into a grinding wheel type sand mixer, then the dry-grinding machine, the dry-grinding wheel type sand mixing machine with the mass fractions of 50-200%, the dry-200.2-mesh of 260-mesh of the dry powder, the dry magnesium powder, the dry-mesh powder and the dry-mesh of 1.2-mesh of 1-200.2-mesh of the dry-mesh of 100-mesh of the dry;
② on the basis of the step ①, adding polyvinyl acetate adhesive, sodium carboxymethylcellulose, a polymer of vinyl acetate, chromium phosphate, sodium bentonite, n-butanol, n-amyl alcohol, formaldehyde, lithium bentonite, attapulgite clay, tween-80, potassium permanganate, cryolite, sodium silicate, starch, fatty alcohol polyoxyethylene ether AEO-03 and water into a grinding wheel type sand mixer, wherein the adding amount of the polyvinyl acetate adhesive, the sodium carboxymethylcellulose, the polymer of vinyl acetate, the chromium phosphate, the sodium bentonite, the n-butanol and the n-amyl alcohol respectively accounts for 0.8-1.0%, 1.2-1.5%, 1.0-1.2%, 0.5-0.6%, 2.0-2.2%, 0.20-0.25%, 0.30-0.35%, formaldehyde, the lithium bentonite, the attapulgite clay, the potassium permanganate, the high-80%, the high-purity, the sodium silicate, the starch, the polyoxyethylene ether, 0.03%, 0.20-0.25%, 0.30-0.35%, 0.6-0.8% and 0.4% of the total mass% of fatty alcohol is added into the grinding wheel type sand mixer to obtain a paste, wherein the adding amount of the paste type wet coating is 0.8-1.5%, 0.6%, 0.4-0.4% and 0.6%, 0.3-0.4% of the total mass% of the paste is obtained in the grinding wheel type sand mixer, 0.6%, 0.4% and 0.3-3.6%, and 0.4% respectively;
③, putting the paste paint in step ② into a stirrer, adding water, controlling the pH value of the water to be 6.2-6.8, controlling the adding amount of the water to be 30-35% of the mass fraction of the paste paint, controlling the peripheral speed of the impeller tip of the stirrer to be 320-350m/min, and stirring for 30-35 minutes to obtain the evaporative pattern casting hardening hollow shell liquid paint.
The lost foam casting coating is generally comparable to a common casting coating and is composed of a variety of materials with different properties, usually including refractory aggregate, carriers, binders, suspending agents, and other additives. The refractory aggregate is the main body of the lost foam coating, in which its mass fraction is generally > 50%. The invention adopts 50-55% of quartz powder, 10-12% of mica powder, 5-6% of expanded perlite powder and 30-33% of sintered mullite powder as refractory aggregate by mass fraction. The refractory aggregate mainly comprises cheap quartz powder, and has strict requirements on the granularity of the refractory aggregate in order to ensure the permeability and strength of the coating, wherein when the quartz powder contains 120-180 meshes of 40 percent, 180-220 meshes of 35 percent, 230-270 meshes of 20 percent and 280-320 meshes of 5 percent; the mica powder comprises 70 percent of 160-grade and 220-grade meshes and 30 percent of 240-grade and 280-grade meshes; 220 meshes of 160-plus-one expanded perlite powder account for 45%, and 280 meshes of 240-plus-one expanded perlite powder account for 55%; when the content of 120-160 meshes, 45% of 180-220 meshes, 12% of 230-270 meshes and 8% of 280-320 meshes in the sintered mullite powder is 35%, the finally obtained coating has good air permeability in the use process, and has high room temperature strength and excellent high temperature strength. After 5-6% of expanded perlite powder is added into the refractory aggregate, the air permeability of the coating can be improved, the stability of the coating can be kept, the surface of the coating after high-temperature sintering becomes very smooth, the pouring speed of molten metal in the casting process is greatly improved, and the appearance quality and the production efficiency of castings can be improved. The lamellar mica with the mass fraction of 30% endows the coating with good suspension property and leveling property, and the coating has good toughness after being dried, so that the coating can be prevented from cracking. The sintered mullite has high refractoriness which can reach over 1790 ℃ and good thermal shock resistance, and in order to ensure the high-temperature strength of the coating, the sintered mullite powder with the mass fraction of 30-33 percent is added into the refractory aggregate.
The carrier of the casting coating can be water and ethanol, and for the lost foam casting coating, the water is used as the carrier, namely the water-based coating, in consideration of the reasons of application, drying, gas forming amount, price and the like. Meanwhile, the water-based paint has good suspension property and thixotropy and is easy to adjust. In addition, the anhydrous magnesium chloride powder accounting for 1.5-2.0% of the total mass fraction of the refractory aggregate is added, so that the high-temperature ceramic formation of inorganic minerals is facilitated, and the ceramic formation of the coating layer during the casting process of the lost foam after the sintering is realized, so that the high-temperature strength of the coating layer can be improved, and the sand adhesion resistance of the coating layer can be improved. Especially, after the magnesium oxide powder accounting for 4.5 to 4.8 percent of the total mass of the refractory aggregate is added, the magnesium oxide powder can be combined with anhydrous magnesium chloride powder, which is beneficial to further improving the strength of a coating layer at high temperature. After the aluminum sulfate powder accounting for 2.8-3.0 percent of the total mass of the refractory aggregate is added, the sintering temperature can be reduced, the ceramic formation of the coating at high temperature is further promoted, and the high-temperature strength of the coating layer is improved. The graphite powder accounting for 1.0-1.2 percent of the total mass of the refractory aggregate is added, so that the air permeability of the coating layer can be improved. In order to uniformly mix all components in the coating and enable the coating to have excellent comprehensive performance, 50-55% of quartz powder, 10-12% of mica powder, 5-6% of expanded perlite powder and 30-33% of sintered mullite powder are dry-mixed in a roller type sand mixer for 25-30 minutes, then 200-260 mesh anhydrous magnesium chloride powder, 200-260 mesh aluminum sulfate powder, 200-260 mesh magnesium oxide powder, 380-420 mesh graphite powder, 1.5-2.0%, 2.8-3.0%, 4.5-4.8% and 1.0-1.2% of the total mass fraction of the refractory aggregate are sequentially added, and the dry-mixing is continuously carried out in the roller type sand mixer for 12-15 minutes.
The binder in the lost foam casting coating is important for improving the strength of the coating layer and the adhesion of the coating layer and the pattern. Not only endows the coating with strength and coating property and improves the suspension property, but also ensures that the coating layer has good adhesiveness and does not react with the pattern. The binder of the common lost foam casting coating mainly comprises clay, water glass, syrup, pulp waste liquid, milk white glue, silica sol and the like. However, the coating is fragile and easy to crack because the sodium silicate binder is singly adopted. The coating is low in strength by singly adopting the binders such as clay, syrup, paper pulp waste liquid, white latex, silica sol and the like, and the production cost of lost foam casting can be greatly increased by increasing the thickness of the coating in the using process. The invention adds polyvinyl acetate adhesive accounting for 0.8-1.0 percent of the mass fraction of the refractory aggregate, 1.2-1.5 percent of sodium carboxymethyl cellulose and 1.0-1.2 percent of polymer of vinyl acetate, wherein the Chinese alias of the polymer of the vinyl acetate is the polymer of (E) -2-butenedioic acid di-C8-18-alkyl ester and the vinyl acetate, and the chemical formula is C8H10O6The addition of the above-mentioned components can ensure coating property of coating material and high strength of coating material at normal temp. On the basis, adding chromium phosphate accounting for 0.5-0.6 percent of the mass fraction of the refractory aggregate and sodium bentonite accounting for 2.0-2.2 percent of the mass fraction of the refractory aggregate to support sandThe shape and the function of resisting the scouring of molten metal. The organic binder and the inorganic binder support the strength together at normal temperature, the organic binder is burnt to increase the air permeability when the evaporative pattern casting is firstly burnt and then poured, and the strength at the moment depends on the inorganic binder.
In addition, n-butanol and n-amyl glycol in the weight portions of 0.20-0.25% and 0.30-0.35% are added to prevent the surface of the paint from foaming during the use process and to make the surface of the paint layer contacting with the mold smooth. The pattern used in lost foam casting is usually Expanded Polystyrene (EPS) or expanded polymethyl methacrylate (EPMMA), and the surface is hydrophobic. In order to change the phenomenon, the invention adds Tween-80 accounting for 0.5 to 0.6 percent of the mass fraction of the refractory aggregate and fatty alcohol-polyoxyethylene ether AEO-03 accounting for 0.6 to 0.7 percent of the mass fraction of the refractory aggregate, wherein Tween-80 is a nonionic surfactant and an emulsifier, and is prepared by ethoxylation of sorbitan and oleic acid, and the addition of Tween-80 accounting for 0.5 to 0.6 percent enables the coating and the model to be wetted so as to improve the bonding strength between the model and the coating layer. The fatty alcohol-polyoxyethylene ether AEO-03, also called polyoxyethylene fatty alcohol ether, is the most rapidly developed and most used variety in the nonionic surfactant. Surfactants of this type are ethers formed by the condensation of polyethylene glycol (PEG) with fatty alcohols, represented by the general formula: RO (CH2CH2O)3H is colorless transparent liquid at room temperature, is nontoxic and nonirritating, has good emulsibility, is an important nonionic surfactant, and can improve the bonding strength between the coating and a pattern used for lost foam casting and prevent the coating from falling off when being used in the coating. The potassium permanganate added into the coating material can prevent the chemical sand-sticking defect caused by the chemical reaction of the molten metal and the coating, and can reduce the crinkle of the iron casting and the recarburization defect of the steel casting.
In the preparation process of the coating, on the basis of dry mixing of refractory aggregates, a polyvinyl acetate adhesive, sodium carboxymethylcellulose, a polymer of vinyl acetate, chromium phosphate, sodium bentonite, n-butanol, n-pentanol, formaldehyde, lithium bentonite, attapulgite clay, tween-80, potassium permanganate, cryolite, sodium silicate, starch, fatty alcohol polyoxyethylene ether AEO-03 and water are added into a grinding wheel type sand mixer, wherein the adding amounts of the polyvinyl acetate adhesive, the sodium carboxymethylcellulose, the polymer of the vinyl acetate, the chromium phosphate, the sodium bentonite, the n-butanol and the n-pentanol respectively account for 0.8-1.0%, 1.2-1.5%, 1.0-1.2%, 0.5-0.6%, 2.0-2.2%, 0.20-0.25% and 0.30-0.35% of the total mass fraction of the refractory aggregates; formaldehyde, lithium bentonite, attapulgite clay, tween-80, potassium permanganate, cryolite, sodium silicate, starch, fatty alcohol-polyoxyethylene ether AEO-03 and water accounting for 0.30-0.35 percent, 0.8-1.0 percent, 1.0-1.2 percent, 0.5-0.6 percent, 0.3-0.4 percent, 0.4-0.5 percent, 0.6-0.7 percent and 8-10 percent of the mass fraction of the refractory aggregate respectively; and then continuously carrying out wet mixing in a grinding wheel type sand mixer for 18-20 minutes to enable the coating to be pasty to obtain a pasty coating, putting the pasty coating into a stirrer, simultaneously adding water, controlling the pH value of the water to be 6.2-6.8, controlling the adding amount of the water to be 30-35% of the mass fraction of the pasty coating, controlling the peripheral speed of the tip of an impeller of the stirrer to be 320-350m/min, and stirring for 30-35 minutes to obtain the evaporative pattern casting hardening hollow shell liquid coating.
Compared with the existing lost foam casting coating, the coating of the invention has the following advantages:
1) the coating has stable performance and good suspension property, and the suspension degree reaches more than 99 percent.
2) The coating layer of the invention can rapidly generate ceramic transformation under the action of molten metal with the pouring temperature of more than 1300 ℃, the strength of the coating layer is greatly improved along with the increase of the pouring temperature of the molten metal and the extension of the pouring time, the coating layer has good erosion resistance of the molten metal, no dust pollution and good toughness, and the coating layer can not crack and peel under the continuous erosion action of the molten metal, and fig. 1 is a surface condition diagram of the coating after 1420 ℃ cast steel is poured.
3) The strength of the coating is greatly improved after the coating is heated and dried for 3-4 hours at 63-66 ℃, so that the evaporative pattern casting can adopt a first-burning and later-pouring process of an evaporative pattern, and the hardened hollow shell casting is realized, thereby greatly improving the quality of castings.
4) The high-temperature bending strength of the coating is high, the coating is easy to sinter, compared with the conventional coating with the coating thickness of 0.4-0.6mm, the high-temperature bending strength of the coating is more than 120MPa and far higher than that of the conventional coating, the coating can be sintered into blocks at high temperature, sand sticking is prevented, and the coating is easy to peel off after a casting is turned over.
5) The coating disclosed by the invention is non-toxic, odorless, green and environment-friendly, is convenient in raw material source, low in manufacturing cost, and good in economic and social benefits when popularized and applied.
Drawings
FIG. 1 is a surface condition diagram of the coating after casting steel of 1420 ℃ in example 1
Detailed Description
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.
Example 1:
the evaporative pattern casting hardening hollow shell coating and the preparation method thereof are characterized in that raw materials are firstly and secondly mixed in a grinding wheel type sand mixer in a dry and wet mode to obtain a paste coating, then the paste coating is put into a stirrer, water is added, and the liquid coating is obtained after stirring, and the specific preparation process comprises the following steps:
①, quartz powder, 12% mica powder, 5% expanded perlite powder and 33% sintered mullite powder are used as refractory aggregate, wherein 160-mesh of 120-mesh sand-doped;
② adding polyvinyl acetate adhesive, sodium carboxymethylcellulose, a polymer of vinyl acetate, chromium phosphate, sodium bentonite, n-butanol, n-amyl alcohol, formaldehyde, lithium bentonite, attapulgite clay, tween-80, potassium permanganate, cryolite, sodium silicate, starch, fatty alcohol polyoxyethylene ether AEO-03 and water into a grinding wheel type sand mixer based on the step ①, wherein the adding amounts of the polyvinyl acetate adhesive, the sodium carboxymethylcellulose, the polymer of vinyl acetate, the chromium phosphate, the sodium bentonite, the n-butanol and the n-amyl alcohol respectively account for 0.8%, 1.5%, 1.0%, 0.6%, 2.0%, 0.25% and 0.30% of the total mass fraction of the refractory aggregate in the step ①, the adding amounts of the formaldehyde, the lithium bentonite, the attapulgite clay, the tween-80, the high-alumina, the sodium silicate, the starch, the fatty alcohol polyoxyethylene ether AEO-03 and the water respectively account for 0.30%, 1.0%, 1.0.6%, 0.0%, 3.6% and 10% of the total mass fraction of the refractory aggregate in the grinding wheel type sand mixer to obtain a paste-like refractory coating material;
③, putting the paste paint in step ② into a stirrer, adding water, controlling the pH value of the water to be 6.2, controlling the adding amount of the water to be 30% of the mass fraction of the paste paint, controlling the peripheral speed of the impeller tip of the stirrer to be 320m/min, and stirring for 35 minutes to obtain the evaporative pattern casting hardening hollow shell liquid paint, wherein the paint properties are shown in Table 1.
Example 2:
the evaporative pattern casting hardening hollow shell coating and the preparation method thereof are characterized in that raw materials are firstly and secondly mixed in a grinding wheel type sand mixer in a dry and wet mode to obtain a paste coating, then the paste coating is put into a stirrer, water is added, and the liquid coating is obtained after stirring, and the specific preparation process comprises the following steps:
①, quartz powder with mass fraction of 55%, mica powder with mass fraction of 10%, expanded perlite powder with mass fraction of 5% and sintered mullite powder with mass fraction of 30% are used as refractory aggregate, wherein 160-mesh of 120-mesh sand-doped sand-;
② adding polyvinyl acetate adhesive, sodium carboxymethylcellulose, a polymer of vinyl acetate, chromium phosphate, sodium bentonite, n-butanol, n-amyl alcohol, formaldehyde, lithium bentonite, attapulgite clay, tween-80, potassium permanganate, cryolite, sodium silicate, starch, fatty alcohol polyoxyethylene ether AEO-03 and water into a grinding wheel type sand mixer based on the step ①, wherein the adding amounts of the polyvinyl acetate adhesive, the sodium carboxymethylcellulose, the polymer of vinyl acetate, the chromium phosphate, the sodium bentonite, the n-butanol and the n-amyl alcohol respectively account for 1.0%, 1.2%, 0.5%, 2.2%, 0.20% and 0.35% of the total mass fraction of the refractory aggregate in the step ①, adding the formaldehyde, the lithium bentonite, the attapulgite clay, the tween-80, the high-alumina, the sodium silicate, the starch, the fatty alcohol polyoxyethylene ether AEO-03 and the water respectively account for 0.35%, 0.8%, 1.8%, 0.5%, 0.4.5%, 4.8% and 4.8% of the total mass fraction of the refractory aggregate in the grinding wheel type sand mixer to obtain a refractory coating paste, and grinding the coating in a grinding wheel type sand mixer;
③, putting the paste paint in step ② into a stirrer, adding water, controlling the pH value of the water to be 6.8, controlling the adding amount of the water to be 35% of the mass fraction of the paste paint, controlling the peripheral speed of the impeller tip of the stirrer to be 350m/min, and stirring for 30 minutes to obtain the evaporative pattern casting hardening hollow shell liquid paint, wherein the paint properties are shown in Table 1.
Example 3:
the evaporative pattern casting hardening hollow shell coating and the preparation method thereof are characterized in that raw materials are firstly and secondly mixed in a grinding wheel type sand mixer in a dry and wet mode to obtain a paste coating, then the paste coating is put into a stirrer, water is added, and the liquid coating is obtained after stirring, and the specific preparation process comprises the following steps:
①, using 51% by mass of quartz powder, 11% by mass of mica powder, 6% by mass of expanded perlite powder and 32% by mass of sintered mullite powder as refractory aggregate, wherein 160-mesh of 120-mesh sand-doped sand accounts for 40%, 220-mesh of 180-mesh sand-doped sand accounts for 35%, 270-mesh of 230-mesh sand-doped sand-;
② on the basis of step ①, adding polyvinyl acetate adhesive, sodium carboxymethylcellulose, a polymer of vinyl acetate, chromium phosphate, sodium bentonite, n-butanol, n-amyl alcohol, formaldehyde, lithium bentonite, attapulgite clay, tween-80, potassium permanganate, cryolite, sodium silicate, starch, fatty alcohol polyoxyethylene ether AEO-03 and water into a grinding wheel type sand mixer, wherein the adding amounts of the polyvinyl acetate adhesive, the sodium carboxymethylcellulose, the polymer of vinyl acetate, the chromium phosphate, the sodium bentonite, the n-butanol and the n-amyl alcohol respectively account for 0.9%, 1.4%, 1.1%, 0.55%, 2.1%, 0.22% and 0.32% of the total mass fraction of the refractory aggregate in step ①, adding the formaldehyde, the lithium bentonite, the attapulgite clay, the tween-80, the high-grade rock, the sodium silicate, the starch, the fatty alcohol polyoxyethylene ether AEO-03 and the water respectively account for 0.32%, 0.9%, 0.35%, 0.45% of the total mass fraction of the refractory aggregate in step ①, and continuously grinding the grinding wheel type sand mixer to obtain a refractory aggregate paste;
③, putting the paste paint in step ② into a stirrer, adding water, controlling the pH value of the water to be 6.6, controlling the adding amount of the water to be 32% of the mass fraction of the paste paint, controlling the peripheral speed of the impeller tip of the stirrer to be 340m/min, and stirring for 33 minutes to obtain the evaporative pattern casting hardening hollow shell liquid paint, wherein the paint properties are shown in Table 1.
TABLE 1 coating Properties
The coating has stable performance and good suspension property, and the suspension degree reaches more than 99 percent. The coating has moderate cup viscosity, poor coating property or poor coating property due to overlarge cup viscosity, and poor coating property due to small cup viscosity. The coating of the invention can rapidly generate ceramic transformation under the action of molten metal with the pouring temperature of more than 1300 ℃, the strength of the coating is greatly improved along with the increase of the pouring temperature of the molten metal and the prolongation of the pouring time, the coating has good erosion resistance of the molten metal, no dust pollution and good toughness, and the coating can not crack and peel under the continuous erosion action of the molten metal. The high-temperature bending strength of the coating is high, the coating is easy to sinter, compared with the conventional coating with the coating thickness of 0.4-0.6mm, the high-temperature bending strength of the coating is more than 120MPa and far higher than that of the conventional coating, the coating can be sintered into blocks at high temperature, sand sticking is prevented, and the coating is easy to peel off after a casting is turned over. The coating disclosed by the invention is non-toxic, odorless, green and environment-friendly, is convenient in raw material source, low in manufacturing cost, and good in economic and social benefits when popularized and applied.
Claims (2)
1. A preparation method of evaporative pattern casting hardening hollow shell coating is provided, wherein the evaporative pattern casting adopts a first-firing and second-pouring process to realize hardening hollow shell pouring; the method is characterized by comprising the following steps:
①, quartz powder with the mass fraction of 50-55%, mica powder with the mass fraction of 10-12%, expanded perlite powder with the mass fraction of 5-6% and sintered mullite powder with the mass fraction of 30-33% are taken as refractory aggregate, wherein 160-mesh of 120-mesh accounts for 40%, 220-mesh of 180-mesh accounts for 35%, 270-mesh of 230-mesh accounts for 20%, 320-mesh of 280-mesh accounts for 5%, 220-mesh of 160-mesh of 240-mesh accounts for 70%, 280-mesh of 240-mesh accounts for 30% in the mica powder, 220-mesh of 160-mesh accounts for 45%, 280-mesh of 240-mesh accounts for 55%, 160-mesh of 120-mesh accounts for 35%, 220-mesh of 180-mesh accounts for 45%, 270-mesh of 230-mesh accounts for 12%, and 320-mesh of 280-mesh accounts for 8% in the expanded perlite powder, firstly, the quartz powder with the mass fraction of 50-55%, the magnesium powder with the mass fraction of 10-12%, the magnesium powder with the mass fraction of 5-6%, the sintered mullite powder and the sintered mullite powder are added into a grinding wheel type sand mixer, then the dry-grinding machine, the dry-grinding wheel type sand mixing machine with the mass fractions of 50-200%, the dry-200.2-mesh of 260-mesh of the dry powder, the dry magnesium powder, the dry-mesh powder and the dry-mesh of 1.2-mesh of 1-200.2-mesh of the dry-mesh of 100-mesh of the dry;
② on the basis of the step ①, adding polyvinyl acetate adhesive, sodium carboxymethylcellulose, a polymer of vinyl acetate, chromium phosphate, sodium bentonite, n-butanol, n-amyl alcohol, formaldehyde, lithium bentonite, attapulgite clay, tween-80, potassium permanganate, cryolite, sodium silicate, starch, fatty alcohol polyoxyethylene ether AEO-03 and water into a grinding wheel type sand mixer, wherein the adding amount of the polyvinyl acetate adhesive, the sodium carboxymethylcellulose, the polymer of vinyl acetate, the chromium phosphate, the sodium bentonite, the n-butanol and the n-amyl alcohol respectively accounts for 0.8-1.0%, 1.2-1.5%, 1.0-1.2%, 0.5-0.6%, 2.0-2.2%, 0.20-0.25%, 0.30-0.35%, formaldehyde, the lithium bentonite, the attapulgite clay, the potassium permanganate, the high-80%, the high-purity, the sodium silicate, the starch, the polyoxyethylene ether, 0.03%, 0.20-0.25%, 0.30-0.35%, 0.6-0.8% and 0.4% of the total mass% of fatty alcohol is added into the grinding wheel type sand mixer to obtain a paste, wherein the adding amount of the paste type wet coating is 0.8-1.5%, 0.6%, 0.4-0.4% and 0.6%, 0.3-0.4% of the total mass% of the paste is obtained in the grinding wheel type sand mixer, 0.6%, 0.4% and 0.3-3.6%, and 0.4% respectively;
③, putting the paste paint in step ② into a stirrer, adding water, controlling the pH value of the water to be 6.2-6.8, controlling the adding amount of the water to be 30-35% of the mass fraction of the paste paint, controlling the peripheral speed of the impeller tip of the stirrer to be 320-350m/min, and stirring for 30-35 minutes to obtain the evaporative pattern casting hardening hollow shell liquid paint.
2. The evaporative pattern casting hardening hollow shell coating prepared according to the method of claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810510387.3A CN108380815B (en) | 2018-05-24 | 2018-05-24 | Lost foam casting hardening hollow shell coating and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810510387.3A CN108380815B (en) | 2018-05-24 | 2018-05-24 | Lost foam casting hardening hollow shell coating and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108380815A CN108380815A (en) | 2018-08-10 |
| CN108380815B true CN108380815B (en) | 2020-06-16 |
Family
ID=63071982
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810510387.3A Active CN108380815B (en) | 2018-05-24 | 2018-05-24 | Lost foam casting hardening hollow shell coating and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108380815B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108788001A (en) * | 2018-08-27 | 2018-11-13 | 河北冀凯铸业有限公司 | A kind of large size alloy cast steel part evaporative pattern water based paint |
| CN108838361B (en) * | 2018-09-04 | 2020-07-31 | 安徽惠明机械制造有限公司 | Casting method of die casting |
| CN110421116A (en) * | 2019-09-16 | 2019-11-08 | 安徽信息工程学院 | A kind of as cast condition WCB cast steel evaporative pattern water base environmental protection coating material and preparation method thereof |
| CN113814348A (en) * | 2020-06-19 | 2021-12-21 | 江门市汉智新材料有限公司 | Special brass casting graphite coating |
| CN111715844B (en) * | 2020-07-02 | 2021-11-09 | 宁夏共享化工有限公司 | Ceramic coating for casting process of evaporative pattern with hollow shell formed by sintering before pouring |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101497104A (en) * | 2009-03-11 | 2009-08-05 | 杨玉光 | Lost foam paint and method for producing the same |
| CN101569918A (en) * | 2009-06-10 | 2009-11-04 | 刘则斌 | Coating for lost foam cast iron |
| CN102397982A (en) * | 2011-11-29 | 2012-04-04 | 朱小英 | Sand casting water-based coating |
| CN102407279A (en) * | 2011-11-29 | 2012-04-11 | 朱小英 | Method for preparing water-based coating for sand mold casting |
| CN102873261A (en) * | 2012-08-31 | 2013-01-16 | 太仓科博尔精密铸业有限公司 | Lost foam coating and preparation method thereof |
| CN104353777A (en) * | 2014-11-05 | 2015-02-18 | 襄阳聚力炉衬材料有限公司 | Cast iron evaporative pattern coating and preparation method thereof |
| CN105817578A (en) * | 2016-05-27 | 2016-08-03 | 马鞍山市兴隆铸造有限公司 | High-breathability mica powder modified quartz-based lost foam paint and preparation method thereof |
| CN107737868A (en) * | 2017-11-08 | 2018-02-27 | 湖北工程职业学院 | A kind of water base lost foam paint of high intensity and preparation method thereof |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102179473A (en) * | 2011-05-11 | 2011-09-14 | 李华山 | Lost foam casting composite coating |
| CN104525851B (en) * | 2014-12-10 | 2017-01-18 | 桂林中铸机械科技有限公司 | High-temperature, ceramic, erosion-resistant, dust-pollution-free and environment-friendly casting coating |
| CN105598419A (en) * | 2016-01-06 | 2016-05-25 | 洛阳市致力新材料有限公司 | Combined casting process of evanescent mode produced hammer head |
| CN105598367B (en) * | 2016-01-06 | 2017-10-24 | 洛阳市致力新材料有限公司 | A kind of method for producing Double-metal composite hammer upside down with evaporative pattern negative pressure of vacuum |
| CN105598369B (en) * | 2016-01-06 | 2018-03-13 | 洛阳市致力新材料有限公司 | A kind of method of evaporative pattern production ceramic particle enhancing bimetallic base tup |
| CN106391999A (en) * | 2016-12-15 | 2017-02-15 | 李文海 | Water base aggressiveness type lost foam coating |
-
2018
- 2018-05-24 CN CN201810510387.3A patent/CN108380815B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101497104A (en) * | 2009-03-11 | 2009-08-05 | 杨玉光 | Lost foam paint and method for producing the same |
| CN101569918A (en) * | 2009-06-10 | 2009-11-04 | 刘则斌 | Coating for lost foam cast iron |
| CN102397982A (en) * | 2011-11-29 | 2012-04-04 | 朱小英 | Sand casting water-based coating |
| CN102407279A (en) * | 2011-11-29 | 2012-04-11 | 朱小英 | Method for preparing water-based coating for sand mold casting |
| CN102873261A (en) * | 2012-08-31 | 2013-01-16 | 太仓科博尔精密铸业有限公司 | Lost foam coating and preparation method thereof |
| CN104353777A (en) * | 2014-11-05 | 2015-02-18 | 襄阳聚力炉衬材料有限公司 | Cast iron evaporative pattern coating and preparation method thereof |
| CN105817578A (en) * | 2016-05-27 | 2016-08-03 | 马鞍山市兴隆铸造有限公司 | High-breathability mica powder modified quartz-based lost foam paint and preparation method thereof |
| CN107737868A (en) * | 2017-11-08 | 2018-02-27 | 湖北工程职业学院 | A kind of water base lost foam paint of high intensity and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108380815A (en) | 2018-08-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108380815B (en) | Lost foam casting hardening hollow shell coating and preparation method thereof | |
| CN102139342B (en) | High-permeability sand-burning-preventing paint for casting and preparation method thereof | |
| CN101497104B (en) | Lost foam paint and method for producing the same | |
| CN102407275B (en) | Expendable pattern casting (EPC) molding shell paint for casting steel and preparation method thereof | |
| CN101767184B (en) | Lost foam casting cast iron coating for preventing carbon defects and preparation method thereof | |
| CN1251823C (en) | Mould for metal casting | |
| CN103506566B (en) | For the coating and preparation method thereof of lost foam casting | |
| CN108097867B (en) | Moisture absorption resistant adhesive and preparation method and application thereof | |
| CN102836952A (en) | Resin sand type casting coating and preparation method thereof | |
| CN104493076B (en) | A kind of calcining quartz powder cast paint and preparation method thereof | |
| CN102357647B (en) | Environmentally-friendly magnesia sand for casting and preparation process thereof | |
| CN109879661B (en) | Tundish coating material and preparation method thereof | |
| CN102873267B (en) | Alcohol-based paint for sand casting and preparation method thereof | |
| CN105170876A (en) | Water-glass sand and preparation and use methods thereof | |
| CN102240776A (en) | Coating for lost mould cast steel and manufacture method thereof | |
| CN105642821A (en) | High-temperature-resistant environment-friendly metal casting coating and preparation method thereof | |
| CN101733360A (en) | Method for sand mulling, modeling and adding facing sand of Furan resin self-hardening sand | |
| CN114309454B (en) | Water-based paint for 3D printing sand core and preparation process thereof | |
| CN104801659A (en) | Self-hardening transferring coating and use method thereof | |
| CN110814273B (en) | Modified molding sand with furan resin loaded with nano ceramic | |
| CN111702124B (en) | High-strength high-toughness cast steel lost foam coating and preparation method thereof | |
| CN102652982A (en) | Lost foam casting coating additive | |
| CN105108043A (en) | Phosphate adhesive sand as well as preparation method and using method thereof | |
| CN103396128B (en) | Casting method of aluminum melting furnace | |
| CN108788001A (en) | A kind of large size alloy cast steel part evaporative pattern water based paint |
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 |