CN110625058B - High-air-permeability foundry molding sand and preparation method thereof - Google Patents
High-air-permeability foundry molding sand and preparation method thereof Download PDFInfo
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- CN110625058B CN110625058B CN201911087164.1A CN201911087164A CN110625058B CN 110625058 B CN110625058 B CN 110625058B CN 201911087164 A CN201911087164 A CN 201911087164A CN 110625058 B CN110625058 B CN 110625058B
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- ball clay
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- 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
- B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
-
- 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
- B22C1/185—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 containing phosphates, phosphoric acids or its derivatives
Abstract
The invention belongs to the technical field of casting, and particularly relates to high-permeability casting molding sand and a preparation method thereof.
Description
Technical Field
The invention belongs to the technical field of casting, and particularly relates to high-permeability casting molding sand and a preparation method thereof.
Background
Sand casting refers to a casting process that produces a casting in a sand mold. Steel, iron and most nonferrous metal castings can be obtained by sand casting. The molding material used for sand casting is cheap and easy to obtain, the casting mould is simple and convenient to manufacture, and the casting mould can adapt to single-piece production, batch production and mass production of castings, and is a basic process in casting production for a long time. The basic raw materials for making sand molds are foundry sand and a sand binder. The most commonly used foundry sand is siliceous sand. When the high-temperature performance of the silica sand can not meet the use requirement, special sand such as zircon sand, chromite sand, corundum sand and the like is used. In order to make the sand molds and cores with certain strength and without deformation or damage during handling, molding and pouring of liquid metal, a sand binder is generally added to the casting to bind the loose sand particles together to form the molding sand. The surface defects of the holes generally refer to air holes, shrinkage cavities, sand holes, slag holes, meat deficiency and the like exposed after the casting is processed. In addition, surface bumps, scratches and the like which appear after the casting is machined belong to the defects. The defects are distributed in an isolated manner, have different shapes and sizes and different positions and have larger randomness. Such defects generally exhibit an adverse distribution, limited depth, visibility, and substrate support, with the potential for repair. The generation reasons of the air holes are that the water content in the molding material is excessive or a large amount of gas-forming substances are contained; the air permeability of the molding sand and the core sand is poor; the pouring speed is too high; the sand hole is caused by insufficient strength of the molding sand; the compactness of the molding sand is insufficient; too fast a pouring speed, etc.
Disclosure of Invention
In view of the above problems, the present invention aims to provide a foundry sand with high air permeability and a preparation method thereof.
The invention is realized by the following technical scheme:
the high-permeability foundry molding sand is prepared from the following components in parts by weight: seawater magnesia, 3-6 parts of magnesium dihydrogen phosphate glue, 8-10 parts of modified diatomite, 2-4 parts of glyceryl monobehenate, 1.5-2.5 parts of polyethyleneimine, 3-5 parts of pyrophyllite powder, 3-6 parts of potassium titanate whisker, 2-5 parts of ball clay, 3.5-4.5 parts of sodium antimonate and 8-12 parts of water; the ball clay is subjected to an activation treatment,
the preparation method of the high-air-permeability foundry molding sand comprises the steps of firstly adding 80-90 parts of seawater magnesia, magnesium dihydrogen phosphate, modified diatomite and glyceryl monobehenate into a Y-shaped mixer, mixing for 10-15 minutes, then adding polyethyleneimine, pyrophyllite powder and potassium titanate whiskers, mixing for 60-90 minutes, finally adding ball clay, sodium antimonate and water, then mixing for 80-100 minutes, and discharging.
Furthermore, the particle size of the seawater magnesite is 0.8-1.0 mm.
Further, the acid activation treatment of the ball clay specifically comprises: calcining ball clay at 350-400 ℃ for 20-30 min, naturally cooling to 25-28 ℃, adding the ball clay into a sodium glutamate solution with the mass fraction of 2-3%, soaking for 10-15 min, taking out, adding the ball clay into a sodium carbonate solution with the mass fraction of 2-5%, soaking for 20-40 min, taking out, cleaning the surface of the ball clay to be neutral by using deionized water, and drying at 110-120 ℃ for 1 h.
Further, the magnesium dihydrogen phosphate gel is a magnesium dihydrogen phosphate solution with the mass fraction of 89%.
Further, the preparation method of the modified diatomite comprises the following steps:
(1) dispersing diatomite into deionized water to prepare a diatomite suspension with the mass fraction of 10%, heating to 80 ℃, adding sodium zirconium lactate with the mass fraction of 5% of the diatomite, uniformly stirring to obtain a mixed solution, adopting an acetic acid solution with the mass fraction of 8-10%, adjusting the pH value of the mixed solution to 3.5, and stirring at the rotating speed of 500r/min for 2 hours to obtain an activation solution;
(2) adding 2-chromium methacrylate chloride accounting for 0.05 percent of the mass of the activating solution prepared in the step (1), heating to 90 ℃, stirring at the rotating speed of 150r/min for 30min, and then standing for 2 hours to obtain a modified solution;
(3) and (3) performing microwave treatment on the modified liquid prepared in the step (2), standing for 2-4 hours, filtering, washing with deionized water to be neutral, and drying for 1 hour, wherein the microwave treatment is performed for 100-180 s under the conditions that the microwave frequency is 2000-2450 MHz and the microwave source power is 100-300 kW.
The invention has the beneficial effects that:
modified treated diatomiteCan only effectively improve SiO in the diatomite2The pore size is increased, and the surface strength is increased. The microwave treatment can effectively remove partial impurities and moisture in the diatomite, increase the pores of the diatomite, increase the surface area of the diatomite, improve the adsorption effect, improve the roasting temperature, facilitate the increase of the specific surface area of the diatomite, have small thermal expansion rate and good thermal stability and chemical stability, do not react with acid and alkali, and carry out modification treatment on the surface of the diatomite so as to improve the adsorption capacity of the diatomite, the seawater magnesia is low in price, and the magnesium dihydrogen phosphate is used as a high-temperature binder and forms a composite binder. The diatomite has close relation with the technological performance of the diatomite in the molding sand, and the diatomite modified by the sodium zirconium lactate has good wet compression strength and wet tensile strength, little sodium modification effect reduction and high reusability when being used for producing the molding sand; soil with poor sodium treatment effect has very quick decline of sodium treatment effect and low reusability, so that diatomite is added in a foundry to cause high mud content of molding sand and even casting defects such as peeling, and the best performance of the soil is exerted in the process of casting and sand mixing through microwave modification and the like.
Compared with the prior art, the invention has the following advantages:
the molding sand disclosed by the invention has the advantages of energy conservation, basic elimination of harmful gas pollution, great reduction of dust pollution and solid waste emission, improvement of surface quality of castings, improvement of internal quality, improvement of dimensional precision, extremely high yield, good reusability of molding sand, less sand consumption and cost reduction, and the product is suitable for production of manually and mechanically molded iron castings.
Detailed Description
The invention is illustrated by the following specific examples, which are not intended to be limiting.
Example 1
The high-permeability foundry molding sand is prepared from the following components in parts by weight: 90 parts of seawater magnesia, 6 parts of magnesium dihydrogen phosphate glue, 10 parts of modified diatomite, 2 parts of glyceryl monobehenate, 1.5 parts of polyethyleneimine, 3 parts of pyrophyllite powder, 3 parts of potassium titanate whisker, 2 parts of ball clay, 3.5 parts of sodium antimonate and 8 parts of water; the ball clay is subjected to an activation treatment,
the preparation method of the high-air-permeability foundry molding sand comprises the steps of adding seawater magnesia, magnesium dihydrogen phosphate gel, modified diatomite and glyceryl monobehenate into a Y-shaped mixer, mixing for 10 minutes, adding polyethyleneimine, pyrophyllite powder and potassium titanate whiskers, mixing for 60 minutes, adding ball clay, sodium antimonate and water, mixing for 80 minutes, and discharging.
Furthermore, the particle size of the seawater magnesite is 0.8-1.0 mm.
Further, the acid activation treatment of the ball clay specifically comprises: calcining ball clay at 350 ℃ for 20min, naturally cooling to 25-28 ℃, adding the ball clay into a sodium glutamate solution with the mass fraction of 2%, soaking for 10min, taking out, adding the ball clay into a sodium carbonate solution with the mass fraction of 2%, soaking for 20min, taking out, cleaning the surface of the ball clay by using deionized water until the surface of the ball clay is neutral, and drying for 1h at 110 ℃.
Further, the magnesium dihydrogen phosphate gel is a magnesium dihydrogen phosphate solution with the mass fraction of 89%.
Further, the preparation method of the modified diatomite comprises the following steps:
(1) dispersing diatomite into deionized water to prepare a diatomite suspension with the mass fraction of 10%, heating to 80 ℃, adding sodium zirconium lactate with the mass fraction of 5% of the diatomite, uniformly stirring to obtain a mixed solution, adopting an acetic acid solution with the mass fraction of 10%, adjusting the pH value of the mixed solution to 3.5, and stirring at the rotating speed of 500r/min for 2 hours to obtain an activation solution;
(2) adding 2-chromium methacrylate chloride accounting for 0.05 percent of the mass of the activating solution prepared in the step (1), heating to 90 ℃, stirring at the rotating speed of 150r/min for 30min, and then standing for 2 hours to obtain a modified solution;
(3) and (3) subjecting the modified liquid prepared in the step (2) to microwave treatment, standing for 2-4 hours, filtering, washing with deionized water to be neutral, and drying for 1 hour, wherein the microwave treatment is carried out at microwave frequency of 2450MHz and microwave source power of 300kW for 180 s.
Example 2
The high-permeability foundry molding sand is prepared from the following components in parts by weight: 90 parts of seawater magnesia, 6 parts of magnesium dihydrogen phosphate glue, 10 parts of modified diatomite, 4 parts of glyceryl monobehenate, 2.5 parts of polyethyleneimine, 3 parts of pyrophyllite powder, 3 parts of potassium titanate whisker, 5 parts of ball clay, 4.5 parts of sodium antimonate and 12 parts of water; the ball clay is subjected to an activation treatment,
the preparation method of the high-air-permeability foundry molding sand comprises the steps of adding seawater magnesia, magnesium dihydrogen phosphate gel, modified diatomite and glyceryl monobehenate into a Y-shaped mixer, mixing for 15 minutes, adding polyethyleneimine, pyrophyllite powder and potassium titanate whiskers, mixing for 90 minutes, adding ball clay, sodium antimonate and water, mixing for 100 minutes, and discharging.
Furthermore, the particle size of the seawater magnesite is 1.0 mm.
Further, the acid activation treatment of the ball clay specifically comprises: calcining ball clay at 400 ℃ for 30min, naturally cooling to 28 ℃, adding the ball clay into a sodium glutamate solution with the mass fraction of 2-3%, soaking for 15min, taking out, adding the ball clay into a sodium carbonate solution with the mass fraction of 5%, soaking for 40min, taking out, cleaning the surface of the ball clay by using deionized water to be neutral, and drying at 120 ℃ for 1 h.
Further, the magnesium dihydrogen phosphate gel is a magnesium dihydrogen phosphate solution with the mass fraction of 89%.
Further, the preparation method of the modified diatomite comprises the following steps:
(1) dispersing diatomite into deionized water to prepare a diatomite suspension with the mass fraction of 10%, heating to 80 ℃, adding sodium zirconium lactate with the mass fraction of 5% of the diatomite, uniformly stirring to obtain a mixed solution, adopting an acetic acid solution with the mass fraction of 10%, adjusting the pH value of the mixed solution to 3.5, and stirring at the rotating speed of 500r/min for 2 hours to obtain an activation solution;
(2) adding 2-chromium methacrylate chloride accounting for 0.05 percent of the mass of the activating solution prepared in the step (1), heating to 90 ℃, stirring at the rotating speed of 150r/min for 30min, and then standing for 2 hours to obtain a modified solution;
(3) and (3) subjecting the modified liquid prepared in the step (2) to microwave treatment, standing for 4 hours, filtering, washing with deionized water to be neutral, and drying for 1 hour, wherein the microwave treatment is carried out at microwave frequency of 2450MHz and microwave source power of 300kW for 180 s.
Comparative example 1
In this comparative example, the modified diatomaceous earth component was omitted when the raw materials were weighed, as compared with example 2, except that the procedure was the same.
Comparative example 2
Compared with the example 2, the magnesium dihydrogen phosphate glue is omitted when the raw materials are weighed, and the steps of the method are the same except that the raw materials are weighed.
Comparative example 3
Compared with the example 2, the comparative example omits ball clay when weighing the raw materials, and has the same steps except the method.
Comparative example 4
Compared with example 2, the procedure of this comparative example is the same except that the polyethyleneimine component is omitted when the raw materials are weighed.
Comparative example 5
Compared with example 2, the method of this comparative example omits pyrophyllite powder when weighing the raw materials, and has the same steps except for the above.
Table 1 comparative results of performance test of foundry sand having high air permeability of examples and comparative examples
| Item | Example 1 | Example 2 | Comparative example 1 | Comparative example 2 | Comparative example 3 | Comparative example 4 | Comparative example 5 |
| Air permeability | 131 | 132 | 123 | 127 | 126 | 125 | 127 |
| Burn and decrement% | 3.3 | 3.3 | 3.2 | 3.4 | 3.5 | 3.4 | 3.2 |
| Compactness% | 45 | 46 | 46 | 46 | 47 | 46 | 45 |
| Wet pressure strength kPa | 63.3 | 62.1 | 62.5 | 62.3 | 62.7 | 61.5 | 61.2 |
| Hot wet tensile strength kPa | 22.2 | 21.7 | 21.5 | 20.6 | 21.5 | 21.8 | 21.6 |
| Wet split strength | 17.1 | 16.4 | 15.8 | 15.6 | 16.1 | 15.4 | 16.2 |
| Content of effective bentonite% | 6.2 | 6.3 | 5.9 | 6.1 | 6.2 | 6.3 | 5.8 |
| Content of effective coal dust% | 3.1 | 3.2 | 3.2 | 3.3 | 3.0 | 3.0 | 2.8 |
| Specific pressure MPa | 0.4 | 0.3 | 0.4 | 0.3 | 0.4 | 0.3 | 0.4 |
| Gas evolution volume mL/g | 15 | 14 | 21 | 22 | 21 | 22 | 23 |
Note: 2kg of green sand of the embodiment and the comparative example is dry-mixed for 2min, then 40mL of water is added, the mixture is mixed for 8min and then wet-ground for 2min, the mixture is placed in a hammer type sampling machine to prepare a standard sample with the diameter of 50mm for detection, and the water content of the green sand is regulated according to GB/T2684-2009; the compaction rate of the green sand is specified in GB/T2684-2009; the air permeability of the green sand is specified according to GB/T2684-2009; the effective bentonite content of the green sand is specified in JB/T9221-2017; the effective coal powder amount of the green sand is specified in JB/T9221-2017; the mud content of the green sand is specified in GB/T2684-2009; gas forming amount, ignition decrement, hot wet tensile strength and wet pressure strength of a mud content process sample are executed according to the regulation of GB/T2684-1981.
As can be seen from Table 1, the high-permeability molding sand disclosed by the invention is high in permeability, is beneficial to removal of casting gasified gas, improves the environment of a casting site, and is beneficial to physical health of workers. The cast casting has good surface quality, high dimensional precision and moderate coating strength, and has popularization and use values.
Claims (3)
1. The casting molding sand with high air permeability is characterized by being prepared from the following components in parts by weight: 80-90 parts of seawater magnesia, 3-6 parts of magnesium dihydrogen phosphate glue, 8-10 parts of modified diatomite, 2-4 parts of glyceryl monobehenate, 1.5-2.5 parts of polyethyleneimine, 3-5 parts of pyrophyllite powder, 3-6 parts of potassium titanate whisker, 2-5 parts of ball clay, 3.5-4.5 parts of sodium antimonate and 8-12 parts of water; the ball clay is subjected to activation treatment, and the ball clay is specifically subjected to acid activation treatment as follows: calcining ball clay at 350-400 ℃ for 20-30 min, naturally cooling to 25-28 ℃, adding the ball clay into a sodium glutamate solution with the mass fraction of 2-3%, soaking for 10-15 min, taking out, adding the ball clay into a sodium carbonate solution with the mass fraction of 2-5%, soaking for 20-40 min, taking out, cleaning the surface of the ball clay to be neutral by using deionized water, and drying at 110-120 ℃ for 1 h; the preparation method of the modified diatomite comprises the following steps: (1) dispersing diatomite into deionized water to prepare a diatomite suspension with the mass fraction of 10%, heating to 80 ℃, adding sodium zirconium lactate with the mass fraction of 5% of the diatomite, uniformly stirring to obtain a mixed solution, adopting an acetic acid solution with the mass fraction of 8-10%, adjusting the pH value of the mixed solution to 3.5, and stirring at the rotating speed of 500r/min for 2 hours to obtain an activation solution; (2) adding 2-chromium methacrylate chloride accounting for 0.05 percent of the mass of the activating solution prepared in the step (1), heating to 90 ℃, stirring at the rotating speed of 150r/min for 30min, and then standing for 2 hours to obtain a modified solution; (3) and (3) performing microwave treatment on the modified liquid prepared in the step (2), standing for 2-4 hours, filtering, washing with deionized water to be neutral, and drying for 1 hour, wherein the microwave treatment is performed under the conditions of microwave frequency of 2000-2450 MHz and microwave source power of 100-300 kW for 100-180 s, the preparation method of the high-permeability foundry molding sand comprises the steps of firstly adding seawater magnesia, magnesium dihydrogen phosphate glue, modified diatomite and glycerol monobehenate in a Y-shaped mixer, mixing for 10-15 minutes, then adding polyethyleneimine, pyrophyllite powder and potassium titanate whiskers, mixing for 60-90 minutes, finally adding ball clay, sodium antimonate and water, mixing for 80-100 minutes, and discharging.
2. The foundry sand with high air permeability according to claim 1, wherein the seawater magnesite grain size is 0.8 to 1.0 mm.
3. The foundry sand with high air permeability of claim 1, wherein the magnesium dihydrogen phosphate gel is a magnesium dihydrogen phosphate solution with a mass fraction of 89%.
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| CN201911087164.1A CN110625058B (en) | 2019-11-08 | 2019-11-08 | High-air-permeability foundry molding sand and preparation method thereof |
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| CN110625058B true CN110625058B (en) | 2021-02-26 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103231011A (en) * | 2013-04-16 | 2013-08-07 | 繁昌县恒鑫汽车零部件有限公司 | Phenol formaldehyde resin precoated sand |
| CN103231010A (en) * | 2013-04-16 | 2013-08-07 | 繁昌县恒鑫汽车零部件有限公司 | Easy-collapsibility type precoated sand |
| CN107214291A (en) * | 2017-04-18 | 2017-09-29 | 芜湖市和蓄机械股份有限公司 | A kind of high temperature resistant, casting sand of high intensity and preparation method thereof |
| CN107363217A (en) * | 2017-08-02 | 2017-11-21 | 合肥市田源精铸有限公司 | A kind of molding sand for improving casting flaw |
| CN107282865B (en) * | 2017-08-30 | 2019-07-16 | 马鞍山市三川机械制造有限公司 | A kind of bentonitic Automobile flywheel casting sand of bismuth-containingization |
| CN107598072A (en) * | 2017-09-30 | 2018-01-19 | 江苏闽江矿业有限公司 | A kind of sand formulation |
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