Water glass carbon dioxide hardened sand for producing basic high manganese steel and its preparation method

Abstract

The application discloses a sodium silicate carbon dioxide hardened sand applied to production of alkaline high manganese steel, which comprises the following raw materials: calcium carbonate sand, quartz sand, forsterite sand, chromite sand, sodium silicate solution, dicyclohexyl phthalate, potassium polyacrylate and micron powder. The application retains good collapsibility of the calcium carbonate sand and alkalinity of the integral sand, is suitable for production of alkaline high manganese steel materials, meanwhile, the high temperature strength and high temperature resistance of the sand are adjusted by adding the forsterite sand, the chromite sand and the quartz sand, and the problems of insufficient high temperature strength of the sand caused by high temperature decomposition of the calcium carbonate sand are compensated. The coactions of the dicyclohexyl phthalate, the potassium polyacrylate and the micron powder are added, the cohesiveness of the sand is well improved, the collapsibility caused by the forsterite sand, the chromite sand and the quartz sand is well solved, the residual strength of the sand is reduced, and the sand can better meet the needs of actual production.

Description

Technical Field

[0001] This invention belongs to the field of casting materials, specifically relating to a water glass carbon dioxide hardening molding sand used in the production of basic high manganese steel and its preparation method. Background Technology

[0002] Sand casting is a casting method that produces castings in sand molds. It has long been a fundamental process in casting production. The basic raw materials for making sand molds are foundry sand and molding sand binders.

[0003] Foundry sand is mainly composed of silica sand (quartz sand), which is widely used due to its abundant sources and low production costs. However, it is an acidic material, which limits its use in the production of basic casting materials (such as high-manganese steel), such as the tendency for chemical sand adhesion to the casting surface. Magnesia olivine sand and chromite sand are suitable for producing basic casting materials, exhibiting good high-temperature stability. However, their high production costs prevent their use in the production of ordinary castings and mass production. Calcium carbonate sand is an alkaline material, suitable for mass production of basic casting materials, and also has low production costs. However, its widespread use is limited by technological and geographical constraints. The most significant characteristic of calcium carbonate molding sand is its decomposition at certain temperatures. While the molding sand exhibits good collapsibility, its poor high-temperature stability leads to a series of problems, including difficulty in guaranteeing the dimensional accuracy of castings.

[0004] Water glass, as a silicate-based inorganic binder, has attracted much attention due to its low gas evolution and environmental friendliness, becoming a dominant product in the foundry binder market. However, the use of water glass binders presents many problems. For example, low amounts of water glass binder result in low strength of the water glass sand, which is detrimental to molding or core making; while excessive amounts make post-pouring sand cleaning extremely difficult. Therefore, many scholars have conducted research on water glass sand, achieving significant breakthroughs, but it still has many shortcomings. Thus, how to solve the problems of poor molding sand adhesion and collapse properties of carbon dioxide water glass sand has become a key research focus and hot topic. Summary of the Invention

[0005] This invention provides a water glass carbon dioxide hardened molding sand for use in the production of basic high manganese steel and its preparation method, in order to solve the problems of poor molding sand adhesion and collapse properties of carbon dioxide water glass sand.

[0006] To solve the above technical problems, the present invention adopts the following technical solution:

[0007] A water glass carbon dioxide hardening molding sand for the production of alkaline high manganese steel comprises the following raw materials in parts by weight: 68-85 parts calcium carbonate sand, 10-15 parts quartz sand, 5-10 parts magnesium olivine sand, 5-10 parts chromite sand, 2-4 parts water glass solution, 1-2 parts dicyclohexyl phthalate, 0.5-1.5 parts potassium polyacrylate, and 0.5-0.8 parts micron powder.

[0008] The micron-sized powder is Zn3N2:Bi(AlO2)3:Zr(NO3)4 in a ratio of (0.2-0.5):

[0009] Mix in a ratio of (0.1-0.3):(0.1-0.3).

[0010] Mechanism of action: Potassium polyacrylate modifies the water glass solution. During the preparation of molding sand, it degrades and hydrolyzes, and attaches to the surface of a mixture of powders such as calcium carbonate sand, quartz sand, magnesium olivine sand, and chromite sand via hydrogen bonds. This forms bonding bridges between sand particles, improving the bonding effect and contributing to the 24-hour strength of the water glass sand. Simultaneously, potassium polyacrylate increases the contact area between the sand particles and the water glass, further enhancing the 24-hour strength of the molding sand. Furthermore, after heating to 800℃, the molten mixture recrystallizes during cooling. Due to the low coefficient of linear expansion of the added potassium polyacrylate, internal stress is generated within the bonding bridges, leading to crack formation and weakening the adhesive effect, effectively reducing residual strength. Based on the addition of potassium polyacrylate, dicyclohexyl phthalate was added to modify water glass sand. Dicyclohexyl phthalate reduces the surface tension of water glass, resulting in a tighter bond between water glass and powder mixtures such as calcium carbonate sand, quartz sand, magnesium olivine sand, and chromite sand. After hardening with carbon dioxide gas, potassium polyacrylate and dicyclohexyl phthalate are more evenly dispersed in the water glass solution, improving the bonding effect and increasing the 24-hour strength of the molding sand. Upon heating to 800℃, the dispersed dicyclohexyl phthalate fully volatilizes, leaving the bonding bridges between sand particles filled with pores and looseness, leading to a decrease in the residual strength of the molding sand. Micron-sized powders have a low coefficient of linear expansion; during the cooling process of molten water glass, micron-sized powder cracks are generated in the bonding bridges, and the volatilization of dicyclohexyl phthalate further improves the collapsibility of the molding sand by reducing the pores created by the bonding bridges.

[0011] Preferably, the raw materials, by weight, include the following: 75 parts calcium carbonate sand, 12 parts quartz sand, 8 parts magnesium olivine sand, 8 parts chromite sand, 3 parts water glass solution, 0.5 parts dicyclohexyl phthalate, 1 part potassium polyacrylate, and 0.7 parts micron powder.

[0012] Preferably, the micron powder is a mixture of Zn3N2:Bi(AlO2)3:Zr(NO3)4 in a ratio of 0.3:0.2:0.2.

[0013] Preferably, the magnesium olivine sand contains 48.29%-58.61% magnesium oxide and has a particle size of 40-80 mesh.

[0014] Preferably, the chromite sand contains 48.5%-61.6% Cr2O3, ≤1.2% SiO2, and ≤0.4% CaO.

[0015] Preferably, the particle size of the chromite sand is 40-100 mesh.

[0016] Preferably, the method for preparing the micron powder is as follows: Zn3N2:Bi(AlO2)3:Zr(NO3)4 are added to a ball mill according to the ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is (1-2):(0.7-1.2), and the rotation speed of the ball mill is 180-200 r / min.

[0017] This invention also provides a method for preparing water glass carbon dioxide hardened molding sand for use in the production of basic high-manganese steel, comprising the following steps:

[0018] S1: Sonicate the water glass solution for 30-60 minutes, add potassium polyacrylate to the sonicated water glass solution, heat it in a water bath to 80-90°C, and simultaneously reflux it. Stir it electromagnetically for 30-40 minutes and then cool it to room temperature.

[0019] S2: Add dicyclohexyl phthalate to step S1, while refluxing and heating in a water bath to 40-60°C, stirring magnetically for 30-60 min, and then cooling to room temperature to obtain a modified water glass solution.

[0020] S3: The raw materials are ground into powder with a particle size greater than 40 mesh by crushing and ball milling. According to the weight parts of the formula, calcium carbonate sand, quartz sand, magnesium olivine sand, chromite sand and micron powder are stirred and mixed to obtain a powder mixture.

[0021] S4: Add the powder mixture to the sand mixing device, and use a liquid pump to uniformly pump the modified water glass solution into the sand mixing device to make the powder mixture uniformly mixed to form a semi-finished product;

[0022] S5: Add the semi-finished product into the sand box containing the mold and compact it;

[0023] S6: Insert a vent hole into the molding sand, insert a rubber hose into the molding sand, introduce carbon dioxide, and control the pressure and time of introducing carbon dioxide to harden the molding sand, thus obtaining a water glass carbon dioxide hardened molding sand cavity suitable for casting basic high manganese steel casting materials.

[0024] Preferably, in step S4, after adding the modified water glass solution to the powder mixture, the mixture is mixed for 1-10 minutes.

[0025] Preferably, in step S6, the flow rate of carbon dioxide is 30-35 L / min, the pressure is 0.12-0.18 MPa, and the time for introducing carbon dioxide is 20-60 s.

[0026] The present invention has the following beneficial effects:

[0027] (1) The present invention improves the adhesion and collapsibility of water glass carbon dioxide hardened molding sand used in the production of alkaline high manganese steel by the combined action of dicyclohexyl phthalate, potassium polyacrylate and micron powder, and reduces the residual strength of the molding sand, which can better meet the needs of actual production.

[0028] (2) This invention retains the good collapsibility and alkalinity of calcium carbonate molding sand, making it suitable for the production of alkaline high manganese steel materials. At the same time, by adding magnesium olivine sand, chromite sand and quartz sand, the high temperature strength and high temperature resistance of the molding sand are adjusted, which makes up for the problem of insufficient high temperature strength of molding sand caused by the high temperature decomposition of calcium carbonate sand.

[0029] (3) Calcium carbonate sand is an alkaline material, which is suitable for mass production of alkaline casting materials. Moreover, the production cost is lower than that of conventional raw material quartz sand. The present invention uses a large amount of calcium carbonate sand in the raw material of water glass carbon dioxide hardening molding sand for the production of alkaline high manganese steel, which can greatly reduce the production cost compared with conventional production. Detailed Implementation

[0030] To facilitate a better understanding of the present invention, the following examples are provided. These examples fall within the scope of protection of the present invention, but do not limit the scope of protection of the present invention.

[0031] In the embodiments, the water glass carbon dioxide hardening molding sand used in the production of alkaline high manganese steel comprises, by weight, the following raw materials: 68-85 parts calcium carbonate sand, 10-15 parts quartz sand, 5-10 parts magnesium olivine sand, 5-10 parts chromite sand, 2-4 parts water glass solution, 1-2 parts dicyclohexyl phthalate, 0.5-1.5 parts potassium polyacrylate, and 0.5-0.8 parts micron powder.

[0032] The micron-sized powder is Zn3N2:Bi(AlO2)3:Zr(NO3)4 in a ratio of (0.2-0.5):

[0033] Mix in a ratio of (0.1-0.3):(0.1-0.3).

[0034] The magnesium olivine sand contains 48.29%-58.61% magnesium oxide and has a particle size of 40-80 mesh.

[0035] The chromite sand contains 48.5%-61.6% Cr2O3, ≤1.2% SiO2, and ≤0.4% CaO.

[0036] The particle size of the chromite sand is 40-100 mesh.

[0037] The method for preparing the micron powder is as follows: Zn3N2:Bi(AlO2)3:Zr(NO3)4 are added to a ball mill according to the ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is (1-2):(0.7-1.2), and the rotation speed of the ball mill is 180-200 r / min.

[0038] The method for preparing water glass carbon dioxide hardened molding sand used in the production of basic high-manganese steel includes the following steps:

[0039] S1: Sonicate the water glass solution for 30-60 minutes, add potassium polyacrylate to the sonicated water glass solution, heat it in a water bath to 80-90°C, and simultaneously reflux it. Stir it electromagnetically for 30-40 minutes and then cool it to room temperature.

[0040] S2: Add dicyclohexyl phthalate to step S1, while refluxing and heating in a water bath to 40-60°C, stirring magnetically for 30-60 min, and then cooling to room temperature to obtain a modified water glass solution.

[0041] S3: The raw materials are ground into powder with a particle size greater than 40 mesh by crushing and ball milling. According to the weight parts of the formula, calcium carbonate sand, quartz sand, magnesium olivine sand, chromite sand and micron powder are stirred and mixed to obtain a powder mixture.

[0042] S4: Add the powder mixture to the sand mixing device, and use a liquid pump to uniformly pump the modified water glass solution into the sand mixing device and mix for 1-10 minutes to make the powder mixture uniformly mixed to form a semi-finished product.

[0043] S5: Add the semi-finished product into the sand box containing the mold and compact it;

[0044] S6: Insert a vent hole into the molding sand, insert a rubber hose into the molding sand, and introduce carbon dioxide. The flow rate of carbon dioxide is 30-35 L / min and the pressure is 0.12-0.18 MPa. The carbon dioxide is introduced for 20-60 seconds to harden the molding sand and obtain a water glass carbon dioxide hardened molding sand cavity suitable for casting basic high manganese steel casting materials.

[0045] The following describes the process through more specific embodiments.

[0046] Example 1

[0047] A water glass carbon dioxide hardening molding sand for the production of alkaline high manganese steel comprises the following raw materials in parts by weight: 75 parts calcium carbonate sand, 12 parts quartz sand, 8 parts magnesium olivine sand, 8 parts chromite sand, 3 parts water glass solution, 0.5 parts dicyclohexyl phthalate, 1 part potassium polyacrylate, and 0.7 parts micron powder.

[0048] The micron powder is a mixture of Zn3N2:Bi(AlO2)3:Zr(NO3)4 in a ratio of 0.3:0.2:0.2.

[0049] The magnesium olivine sand has a magnesium oxide content of 55.66% and a particle size of 40 mesh.

[0050] The chromite sand contains 61.3% Cr2O3, 1.1% SiO2, and 0.36% CaO.

[0051] The chromite sand has a particle size of 40 mesh.

[0052] The preparation method of the micron powder is as follows: Zn3N2:Bi(AlO2)3:Zr(NO3)4 are added to a ball mill according to the ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is 1:0.7, and the rotation speed of the ball mill is 200 r / min.

[0053] The method for preparing water glass carbon dioxide hardened molding sand used in the production of basic high-manganese steel includes the following steps:

[0054] S1: Sonicate the water glass solution for 30 minutes, add potassium polyacrylate to the sonicated water glass solution, heat it to 85°C in a water bath while refluxing, stir it electromagnetically for 30 minutes and then cool it to room temperature.

[0055] S2: Add dicyclohexyl phthalate to step S1, while refluxing and heating in a water bath to 50°C, stirring magnetically for 60 min, and then cooling to room temperature to obtain a modified water glass solution.

[0056] S3: The raw materials are ground into powder with a particle size greater than 40 mesh by crushing and ball milling. According to the weight parts of the formula, calcium carbonate sand, quartz sand, magnesium olivine sand, chromite sand and micron powder are stirred and mixed to obtain a powder mixture.

[0057] S4: Add the powder mixture to the sand mixing device, and use a liquid pump to uniformly pump the modified water glass solution into the sand mixing device and mix for 5 minutes to make the powder mixture uniformly mixed to form a semi-finished product.

[0058] S5: Add the semi-finished product into the sand box containing the mold and compact it;

[0059] S6: Insert a vent hole into the molding sand, insert a rubber hose into the molding sand, and introduce carbon dioxide. The flow rate of carbon dioxide is 35L / min and the pressure is 0.16MPa. The carbon dioxide is introduced for 20s to harden the molding sand and obtain a water glass carbon dioxide hardened molding sand cavity suitable for casting basic high manganese steel casting materials.

[0060] Example 2

[0061] A water glass carbon dioxide hardening molding sand for the production of alkaline high manganese steel comprises the following raw materials in parts by weight: 85 parts calcium carbonate sand, 13 parts quartz sand, 9 parts magnesium olivine sand, 6 parts chromite sand, 3 parts water glass solution, 2 parts dicyclohexyl phthalate, 1.5 parts potassium polyacrylate, and 0.8 parts micron powder.

[0062] The micron powder is a mixture of Zn3N2:Bi(AlO2)3:Zr(NO3)4 in a ratio of 0.2:0.1:0.1.

[0063] The magnesium olivine sand has a magnesium oxide content of 58.61% and a particle size of 60 mesh.

[0064] The chromite sand contains 48.5% Cr2O3, 1.2% SiO2, and 0.38% CaO.

[0065] The chromite sand has a particle size of 80 mesh.

[0066] The preparation method of the micron powder is as follows: Zn3N2:Bi(AlO2)3:Zr(NO3)4 are added to a ball mill according to the ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is 1.5:1, and the rotation speed of the ball mill is 180 r / min.

[0067] The method for preparing water glass carbon dioxide hardened molding sand used in the production of basic high-manganese steel includes the following steps:

[0068] S1: Sonicate the water glass solution for 40 minutes, add potassium polyacrylate to the sonicated water glass solution, heat it to 90°C in a water bath while refluxing, stir it electromagnetically for 35 minutes and then cool it to room temperature.

[0069] S2: Add dicyclohexyl phthalate to step S1, while refluxing and heating in a water bath to 60°C, stirring magnetically for 30 min and then cooling to room temperature to obtain a modified water glass solution.

[0070] S3: The raw materials are ground into powder with a particle size greater than 40 mesh by crushing and ball milling. According to the weight parts of the formula, calcium carbonate sand, quartz sand, magnesium olivine sand, chromite sand and micron powder are stirred and mixed to obtain a powder mixture.

[0071] S4: Add the powder mixture to the sand mixing device, and use a liquid pump to uniformly pump the modified water glass solution into the sand mixing device and mix for 10 minutes to make the powder mixture uniformly mixed to form a semi-finished product.

[0072] S5: Add the semi-finished product into the sand box containing the mold and compact it;

[0073] S6: Insert a vent hole into the molding sand, insert a rubber hose into the molding sand, and introduce carbon dioxide. The flow rate of carbon dioxide is 30L / min and the pressure is 0.18MPa. The carbon dioxide is introduced for 30s, which hardens the molding sand and produces a water glass carbon dioxide hardened molding sand cavity suitable for casting basic high manganese steel casting materials.

[0074] Example 3

[0075] A water glass carbon dioxide hardening molding sand for the production of alkaline high manganese steel comprises the following raw materials in parts by weight: 68 parts calcium carbonate sand, 15 parts quartz sand, 10 parts magnesium olivine sand, 9 parts chromite sand, 4 parts water glass solution, 1 part dicyclohexyl phthalate, 0.5 parts potassium polyacrylate, and 0.5 parts micron powder.

[0076] The micron powder is a mixture of Zn3N2:Bi(AlO2)3:Zr(NO3)4 in a ratio of 0.4:0.2:0.1.

[0077] The magnesium olivine sand has a magnesium oxide content of 48.29% and a particle size of 80 mesh.

[0078] The chromite sand contains 54.23% Cr2O3, 1.05% SiO2, and 0.3% CaO.

[0079] The chromite sand has a particle size of 100 mesh.

[0080] The preparation method of the micron powder is as follows: Zn3N2:Bi(AlO2)3:Zr(NO3)4 are added to a ball mill according to the ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is 2:1.1, and the rotation speed of the ball mill is 190 r / min.

[0081] The method for preparing water glass carbon dioxide hardened molding sand used in the production of basic high-manganese steel includes the following steps:

[0082] S1: Sonicate the water glass solution for 60 minutes, add potassium polyacrylate to the sonicated water glass solution, heat it to 80°C in a water bath while refluxing, stir it electromagnetically for 40 minutes and then cool it to room temperature.

[0083] S2: Add dicyclohexyl phthalate to step S1, while refluxing and heating in a water bath to 40°C, stirring magnetically for 40 min, and then cooling to room temperature to obtain a modified water glass solution.

[0084] S3: The raw materials are ground into powder with a particle size greater than 40 mesh by crushing and ball milling. According to the weight parts of the formula, calcium carbonate sand, quartz sand, magnesium olivine sand, chromite sand and micron powder are stirred and mixed to obtain a powder mixture.

[0085] S4: Add the powder mixture to the sand mixing device, and use a liquid pump to uniformly pump the modified water glass solution into the sand mixing device and mix for 1 minute to make the powder mixture uniformly mixed to form a semi-finished product.

[0086] S5: Add the semi-finished product into the sand box containing the mold and compact it;

[0087] S6: Insert a vent hole into the molding sand, insert a rubber hose into the molding sand, and introduce carbon dioxide. The flow rate of carbon dioxide is 32L / min and the pressure is 0.12MPa. The carbon dioxide is introduced for 60s to harden the molding sand and obtain a water glass carbon dioxide hardened molding sand cavity suitable for casting basic high manganese steel casting materials.

[0088] Example 4

[0089] A water glass carbon dioxide hardening molding sand for the production of alkaline high manganese steel comprises the following raw materials in parts by weight: 72 parts calcium carbonate sand, 11 parts quartz sand, 6 parts magnesium olivine sand, 5 parts chromite sand, 2 parts water glass solution, 1.5 parts dicyclohexyl phthalate, 1.2 parts potassium polyacrylate, and 0.6 parts micron powder.

[0090] The micron powder is a mixture of Zn3N2:Bi(AlO2)3:Zr(NO3)4 in a ratio of 0.5:0.3:0.3.

[0091] The magnesium olivine sand has a magnesium oxide content of 51.21% and a particle size of 60 mesh.

[0092] The chromite sand contains 51.6% Cr2O3, 1.16% SiO2, and 0.32% CaO.

[0093] The chromite sand has a particle size of 80 mesh.

[0094] The preparation method of the micron powder is as follows: Zn3N2:Bi(AlO2)3:Zr(NO3)4 are added to a ball mill according to the ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is 1.6:0.9, and the rotation speed of the ball mill is 190 r / min.

[0095] The method for preparing water glass carbon dioxide hardened molding sand used in the production of basic high-manganese steel includes the following steps:

[0096] S1: Sonicate the water glass solution for 50 minutes, add potassium polyacrylate to the sonicated water glass solution, heat it to 85°C in a water bath while refluxing, stir it electromagnetically for 35 minutes and then cool it to room temperature.

[0097] S2: Add dicyclohexyl phthalate to step S1, while refluxing and heating in a water bath to 50°C, stirring magnetically for 50 min, and then cooling to room temperature to obtain a modified water glass solution.

[0098] S3: The raw materials are ground into powder with a particle size greater than 40 mesh by crushing and ball milling. According to the weight parts of the formula, calcium carbonate sand, quartz sand, magnesium olivine sand, chromite sand and micron powder are stirred and mixed to obtain a powder mixture.

[0099] S4: Add the powder mixture to the sand mixing device, and use a liquid pump to uniformly pump the modified water glass solution into the sand mixing device and mix for 6 minutes to make the powder mixture uniformly mixed to form a semi-finished product.

[0100] S5: Add the semi-finished product into the sand box containing the mold and compact it;

[0101] S6: Insert a vent hole into the molding sand, insert a rubber hose into the molding sand, and introduce carbon dioxide. The flow rate of carbon dioxide is 33L / min and the pressure is 0.14MPa. The carbon dioxide is introduced for 30s to harden the molding sand and obtain a water glass carbon dioxide hardened molding sand cavity suitable for casting basic high manganese steel casting materials.

[0102] Comparative Example 1

[0103] The preparation process is basically the same as that in Example 2, except that the raw materials for preparing water glass carbon dioxide hardened molding sand used in the production of alkaline high manganese steel are missing dicyclohexyl phthalate, potassium polyacrylate, and micron powder.

[0104] Comparative Example 2

[0105] The preparation process is basically the same as that in Example 2, except that dicyclohexyl phthalate is missing from the raw materials for preparing water glass carbon dioxide hardened molding sand used in the production of alkaline high manganese steel.

[0106] Comparative Example 3

[0107] The preparation process is basically the same as that in Example 2, except that potassium polyacrylate is missing from the raw materials for preparing water glass carbon dioxide hardened molding sand used in the production of alkaline high manganese steel.

[0108] Comparative Example 4

[0109] The preparation process is basically the same as that in Example 2, except that the raw materials for preparing water glass carbon dioxide hardened molding sand used in the production of alkaline high manganese steel lack micron powder.

[0110] The water glass carbon dioxide hardened molding sands prepared in Examples 1-4 and Comparative Examples 1-4 for the production of basic high manganese steel were tested for adhesion and collapse properties. The higher the strength of the molding sand at 24 hours, the better the adhesion effect. The lower the residual compressive strength at 800°C, the higher the collapse property of the molding sand. The results are shown in the table below.

[0111]

[0112] As can be seen from the table above: (1) As can be seen from the data of Examples 1-4 and Comparative Examples 1-4, the raw materials for preparing water glass carbon dioxide hardened molding sand used in the production of alkaline high manganese steel lack dicyclohexyl phthalate, potassium polyacrylate, and micron powder, which all have a significant impact on the adhesion and collapsibility of water glass carbon dioxide hardened molding sand used in the production of alkaline high manganese steel. Among them, Example 1 is the best example.

[0113] (2) As can be seen from the data of Example 1 and Comparative Examples 1-4, dicyclohexyl phthalate, potassium polyacrylate, and micronized powder play a synergistic role in the preparation of water glass carbon dioxide hardened molding sand for the production of basic high-manganese steel. This synergistic effect improves the adhesion and collapsibility of the water glass carbon dioxide hardened molding sand used in the production of basic high-manganese steel. This may be because:

[0114] This invention utilizes potassium polyacrylate to modify water glass solution. During the preparation of molding sand, it undergoes degradation and hydrolysis, and attaches to the surface of a mixture of powders such as calcium carbonate sand, quartz sand, magnesium olivine sand, and chromite sand via hydrogen bonds. This forms bonding bridges between sand particles, improving the bonding effect and contributing to the increase of the 24-hour strength of the water glass sand. Simultaneously, potassium polyacrylate increases the contact area between the sand particles and water glass, further enhancing the 24-hour strength of the molding sand. Furthermore, after heating to 800℃, the molten mixture recrystallizes during cooling. Due to the low coefficient of linear expansion of the added potassium polyacrylate, internal stress is generated within the bonding bridges, leading to crack formation and weakening the adhesive effect, thus effectively reducing residual strength. By adding dicyclohexyl phthalate to water glass sand without potassium polyacrylate, the surface tension of water glass is reduced, resulting in a tighter bond between water glass and powder mixtures such as calcium carbonate sand, quartz sand, magnesium olivine sand, and chromite sand. After hardening with carbon dioxide gas, potassium polyacrylate and dicyclohexyl phthalate are more evenly dispersed in the water glass solution, improving the bonding effect and increasing the 24-hour strength of the molding sand. However, after heating to 800℃, the dispersed dicyclohexyl phthalate fully volatilizes, and the bonding bridges between sand particles become porous and loose, leading to a decrease in the residual strength of the molding sand. Micron-sized powders (Zn3N2, Bi(AlO2)3, Zr(NO3)4) have low coefficients of linear expansion. During the cooling process of molten water glass, micron-sized powder cracks are generated in the bonding bridges. Furthermore, the volatilization of dicyclohexyl phthalate causes pores in the bonding bridges, which effectively improves the collapsibility of the molding sand.

[0115] The above content should not be construed as limiting the specific implementation of this invention to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of this invention, and all such deductions or substitutions should be considered as falling within the patent protection scope defined by the submitted claims.

Claims

1. A water glass carbon dioxide hardening molding sand used in the production of basic high-manganese steel, characterized in that, The following raw materials are included in parts by weight: 68-85 parts calcium carbonate sand, 10-15 parts quartz sand, 5-10 parts magnesium olivine sand, 5-10 parts chromite sand, 2-4 parts water glass solution, 1-2 parts dicyclohexyl phthalate, 0.5-1.5 parts potassium polyacrylate, and 0.5-0.8 parts micron powder. The magnesium oxide content in the forsterite sand is 48.29%-58.61%, and the particle size is 40-80 mesh. The chromite sand contains 48.5%-61.6% Cr2O3, ≤1.2% SiO2, and ≤0.4% CaO. The particle size of the chromite sand is 40-100 mesh; The micron-sized powder is a mixture of Zn3N2:Bi(AlO2)3:Zr(NO3)4 in a ratio of (0.2-0.5):(0.1-0.3):(0.1-0.3). The preparation method of the micron powder is as follows: Zn3N2:Bi(AlO2)3:Zr(NO3)4 are added to a ball mill according to the ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is (1-2):(0.7-1.2), and the rotation speed of the ball mill is 180-200 r / min.

2. The water glass carbon dioxide hardening molding sand used in the production of basic high-manganese steel according to claim 1, characterized in that, The following raw materials are included in parts by weight: 75 parts calcium carbonate sand, 12 parts quartz sand, 8 parts magnesium olivine sand, 8 parts chromite sand, 3 parts water glass solution, 0.5 parts dicyclohexyl phthalate, 1 part potassium polyacrylate, and 0.7 parts micron powder.

3. The water glass carbon dioxide hardening molding sand used in the production of basic high-manganese steel according to claim 1, characterized in that, The micron powder is a mixture of Zn3N2:Bi(AlO2)3:Zr(NO3)4 in a ratio of 0.3:0.2:0.

2.

4. A method for preparing water glass carbon dioxide hardened molding sand for producing basic high-manganese steel according to any one of claims 1-3, characterized in that, Includes the following steps: S1: Sonicate the water glass solution for 30-60 minutes, add potassium polyacrylate to the sonicated water glass solution, heat it in a water bath to 80-90°C, and simultaneously reflux it. Stir it electromagnetically for 30-40 minutes and then cool it to room temperature. S2: Add dicyclohexyl phthalate to step S1, while refluxing and heating in a water bath to 40-60°C, stirring magnetically for 30-60 min, and then cooling to room temperature to obtain a modified water glass solution. S3: The raw materials are ground into powder with a particle size greater than 40 mesh by crushing and ball milling. According to the weight parts of the formula, calcium carbonate sand, quartz sand, magnesium olivine sand, chromite sand and micron powder are stirred and mixed to obtain a powder mixture. S4: Add the powder mixture to the sand mixing device, and use a liquid pump to uniformly pump the modified water glass solution into the sand mixing device to make the powder mixture uniformly mixed to form a semi-finished product; S5: Add the semi-finished product into the sand box containing the mold and compact it; S6: Insert a vent hole into the molding sand, insert a rubber hose into the molding sand, introduce carbon dioxide, and control the pressure and time of introducing carbon dioxide to harden the molding sand, thus obtaining a water glass carbon dioxide hardened molding sand cavity suitable for casting basic high manganese steel casting materials.

5. The method for preparing water glass carbon dioxide hardened molding sand for producing basic high-manganese steel according to claim 4, characterized in that, In step S4, the modified water glass solution is added to the powder mixture and then mixed for 1-10 minutes.

6. The method for preparing water glass carbon dioxide hardened molding sand for producing basic high-manganese steel according to claim 4, characterized in that, In step S6, the carbon dioxide flow rate is 30-35 L / min, the pressure is 0.12-0.18 MPa, and the carbon dioxide is introduced for 20-60 seconds.

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