High-performance sodium silicate ester hardened sand, production process and application thereof in casting of alkaline high manganese steel

Abstract

The application discloses high-performance sodium silicate ester hardened sand, a production process and application of the high-performance sodium silicate ester hardened sand in casting of alkaline high-manganese steel, and the high-performance sodium silicate ester hardened sand comprises the following raw materials in parts by weight: calcium carbonate sand 70-90 parts, forsterite sand 10-20 parts, cullisite sand 5-10 parts, sodium silicate solution 2-4 parts, lithium hydroxide 0.8-1.5 parts, polystyrene resin 2-4 parts, polymethyl acrylate 1-3 parts, micron powder 0.3-0.6 parts and glyceryl triacetate 0.2-0.6 parts. The process retains the collapsibility of the calcium carbonate sand, the room temperature and high-temperature strength of the sand is improved by adding the forsterite sand and the cullisite sand, and the strength and collapsibility of the prepared sodium silicate ester hardened sand are excellent due to the synergistic effect of the polystyrene resin, the polymethyl acrylate and the micron powder, so that the application requirement in the casting of the alkaline high-manganese steel can be met.

Description

Technical Field

[0001] This invention belongs to the field of casting materials, specifically relating to a high-performance water glass ester hardened molding sand, its production process, and its application in casting alkaline high-manganese steel. Background Technology

[0002] High manganese steel is an alkaline material. During the casting process, to prevent sand from adhering to the steel, non-quartz raw sand is generally used, such as magnesium olivine sand, chromite sand, corundum sand (corundum sand), and calcium carbonate sand. Due to the high cost of magnesium olivine sand, chromite sand, and corundum sand (corundum sand), manufacturers generally only choose them as surface sand to produce alkaline materials such as high manganese steel.

[0003] The reason why quartz sand is prone to sticking when producing alkaline high-manganese steel is that due to its high manganese content, the molten steel contains a lot of alkaline oxide MnO. MnO is alkaline at high temperatures and is very easy to react chemically with the raw quartz sand (whose main component is acidic oxide SiO2) or coatings containing acidic refractory materials.

[0004] The main component of the magnesium olivine sand used in the production of basic high manganese steel is Mg2SiO4, without free SiO2. The refractoriness of the magnesium olivine sand generally used is around 1700℃. It has high temperature resistance and corrosion resistance, and does not have the phase transformation expansion of quartz sand. Its chemical properties are relatively stable.

[0005] Chromite sand and corundum sand (corundum sand) have high melting points, good thermal conductivity and high-temperature stability, but are rarely used due to the high cost of raw materials.

[0006] Calcium carbonate sand is an alkaline material with low raw material costs and good molding sand collapse properties, but its use cannot be widely promoted due to its limited production location and poor high-temperature stability.

[0007] Currently, the production of high-manganese steel castings mainly employs CO2 hardening or ester hardening processes. However, when using magnesium olivine sand, chromite sand, corundum sand (jewel sand), or quartz sand with water glass as a binder, the following problems still exist: ① This type of water glass sand has very low strength, especially its instantaneous strength, resulting in a long demolding time and low production efficiency; ② Due to the low strength of this molding sand, in order to meet the strength requirements of production, the amount of water glass added must be increased, leading to poor core sand collapsibility and making casting debris removal very difficult.

[0008] Therefore, how to solve the problems of low instantaneous strength and poor collapsibility when using water glass as a binder in the currently used magnesium olivine sand, chromite sand, corundum sand (jewel sand) or quartz sand has become the focus and hot topic of research. Summary of the Invention

[0009] This invention provides a high-performance water glass ester hardened molding sand, its production process, and its application in casting basic high-manganese steel, in order to solve the problems of low instantaneous strength and poor collapsibility of currently used magnesium olivine sand, chromite sand, corundum sand (jewel sand), or quartz sand using water glass as a binder.

[0010] To solve the above technical problems, the present invention adopts the following technical solution:

[0011] A high-performance water glass ester hardened molding sand, comprising the following raw materials in parts by weight: 70-90 parts calcium carbonate sand, 10-20 parts magnesium olivine sand, 5-10 parts granulated sand, 2-4 parts water glass solution, 0.8-1.5 parts lithium hydroxide, 2-4 parts polystyrene resin, 1-3 parts polymethyl methacrylate, 0.3-0.6 parts micron powder, and 0.2-0.6 parts triacetyl ester;

[0012] The micron powder is a mixture of basic calcium carbonate, microsilica powder, and boron nitride in a ratio of (1-1.5):(1-2):(0.1-0.8).

[0013] Working principle: This invention modifies water glass with polystyrene resin, making it easier for the water glass to adhere to the surface of the sand particles, thus improving its strength. Polymethyl methacrylate crosslinks the water glass and polystyrene resin, allowing them to interact during hardening to form shared bonding bridges and further enhancing the strength of the original water glass sand. Furthermore, at high temperatures, the polymethyl methacrylate decomposes to release gas, reducing the residual strength of the molding sand and improving its collapsibility. After modification with lithium hydroxide and polystyrene resin, the addition of organic components to the system improves the surface quality of the molding sand and alters the atmosphere during casting. The lithium hydroxide and polystyrene resin provide a reducing atmosphere for the molding sand system, controlling sand adhesion, preventing vein formation to some extent, significantly reducing residual strength, and simplifying sand cleaning. Micron-sized powder has a low coefficient of linear expansion. During the cooling process of molten water glass, micron-sized powder cracks are generated in the bonding bridge. At the same time, the micron-sized powder can uniformly coat the sand particles, making the water glass and sand particles tightly bonded, thereby improving the strength of the molding sand. Furthermore, the volatilization of polymethyl methacrylate causes the pores generated by the bonding bridge, which effectively improves the collapsibility of the molding sand.

[0014] Preferably, the raw materials, by weight, include the following: 80 parts calcium carbonate sand, 16 parts magnesium olivine sand, 8 parts granulated sand, 3 parts water glass solution, 1 part lithium hydroxide, 3 parts polystyrene resin, 2 parts polymethyl methacrylate, 0.4 parts micron powder, and 0.3 parts triacetyl ester.

[0015] Preferably, the micron powder is a mixture of basic calcium carbonate, microsilica powder, and boron nitride in a ratio of 1.2:1.5:0.5.

[0016] Preferably, the magnesium olivine sand contains 48.29%-58.61% magnesium oxide and has a particle size of 40-80 mesh.

[0017] Preferably, the particle size of the abrasive is 40-100 mesh.

[0018] Preferably, the method for preparing the micron powder is as follows: basic calcium carbonate, microsilica powder, and boron nitride are added to a ball mill according to the specified ratio, and then anhydrous ethanol is added and mixed. The ratio of the amount of micron powder to anhydrous ethanol is (1-2):(0.5-1).

[0019] Preferably, the rotational speed of the ball mill is 200-250 r / min.

[0020] A method for preparing high-performance water glass ester hardened molding sand includes the following steps:

[0021] S1: Sonicate the water glass solution for 30-60 minutes, add lithium hydroxide to the sonicated water glass solution, heat to 60-90℃, stir for 30-40 minutes, and then cool to room temperature;

[0022] S2: Add polystyrene resin and micron powder to step S1, heat to 90-110℃, stir for 30-60 min, cool to 30-40℃, and then add polymethyl methacrylate to obtain the modified product.

[0023] S3: Grind the raw materials into powder with a particle size greater than 40 mesh by crushing and ball milling. According to the weight parts of the formula, stir and mix calcium carbonate sand, magnesium olivine sand, granulated sand and triacetyl ester for 20-60 seconds to obtain a powder mixture.

[0024] S4: Add the powder mixture to the sand mixing device, add the modifier from step S2 and mix for 20-60 seconds to obtain high-performance water glass ester hardened molding sand.

[0025] Preferably, in step S2, polystyrene resin and micron powder are added to step S1, heated to 100°C, stirred for 40 minutes, cooled to 35°C, and then polymethyl methacrylate is added.

[0026] The present invention also provides an application of high-performance water glass ester hardened molding sand, which is used for casting alkaline high manganese steel.

[0027] The present invention has the following beneficial effects:

[0028] (1) The process of the present invention, through the combined action of polystyrene resin, polymethyl methacrylate and micron powder, makes the water glass ester hardened molding sand have good data on 2h strength, 24h strength and residual strength at 800℃, indicating that the strength and collapsibility are excellent and can meet the application requirements in casting basic high manganese steel.

[0029] (2) The process of this invention retains the collapsibility of calcium carbonate molding sand, improves the room temperature and high temperature strength of molding sand by adding magnesium olivine sand and pebbly sand, and greatly reduces production costs due to the large amount of lower-cost calcium carbonate sand used. 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 high-performance water glass ester hardened molding sand comprises, by weight, the following raw materials: 70-90 parts calcium carbonate sand, 10-20 parts magnesium olivine sand, 5-10 parts granulated sand, 2-4 parts water glass solution, 0.8-1.5 parts lithium hydroxide, 2-4 parts polystyrene resin, 1-3 parts polymethyl methacrylate, 0.3-0.6 parts micron powder, and 0.2-0.6 parts triacetyl ester;

[0032] The micron powder is a mixture of basic calcium carbonate, microsilica powder, and boron nitride in a ratio of (1-1.5):(1-2):(0.1-0.8).

[0033] The magnesium olivine sand contains 48.29%-58.61% magnesium oxide and has a particle size of 40-80 mesh.

[0034] The particle size of the agate sand is 40-100 mesh.

[0035] The preparation method of the micron powder is as follows: basic calcium carbonate, microsilica powder, and boron nitride are added to a ball mill according to the specified ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is (1-2):(0.5-1), and the rotation speed of the ball mill is 200-250 r / min.

[0036] A method for preparing high-performance water glass ester hardened molding sand includes the following steps:

[0037] S1: Sonicate the water glass solution for 30-60 minutes, add lithium hydroxide to the sonicated water glass solution, heat to 60-90℃, stir for 30-40 minutes, and then cool to room temperature;

[0038] S2: Add polystyrene resin and micron powder to step S1, heat to 90-110℃, stir for 30-60 min, cool to 30-40℃, and then add polymethyl methacrylate to obtain the modified product.

[0039] S3: Grind the raw materials into powder with a particle size greater than 40 mesh by crushing and ball milling. According to the weight parts of the formula, stir and mix calcium carbonate sand, magnesium olivine sand, granulated sand and triacetyl ester for 20-60 seconds to obtain a powder mixture.

[0040] S4: Add the powder mixture to the sand mixing device, add the modifier from step S2 and mix for 20-60 seconds to obtain high-performance water glass ester hardened molding sand.

[0041] The following describes the process through more specific embodiments.

[0042] Example 1

[0043] A high-performance water glass ester hardened molding sand, in parts by weight, comprises the following raw materials: 70 parts calcium carbonate sand, 11 parts magnesium olivine sand, 9 parts granulated sand, 2 parts water glass solution, 0.8 parts lithium hydroxide, 3 parts polystyrene resin, 2 parts polymethyl methacrylate, 0.4 parts micron powder, and 0.6 parts triacetyl ester.

[0044] The micron-sized powder is a mixture of basic calcium carbonate, microsilica powder, and boron nitride in a ratio of 1.1:1.6:0.5.

[0045] The magnesium olivine sand has a magnesium oxide content of 58.61% and a particle size of 40 mesh.

[0046] The particle size of the agate sand is 100 mesh.

[0047] The method for preparing the micron powder is as follows: basic calcium carbonate, microsilica powder, and boron nitride are added to a ball mill according to the specified ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is 1:0.5, and the rotation speed of the ball mill is 250 r / min.

[0048] A method for preparing high-performance water glass ester hardened molding sand includes the following steps:

[0049] S1: Sonicate the water glass solution for 50 min, add lithium hydroxide to the sonicated water glass solution, heat to 75°C, stir for 33 min, and then cool to room temperature.

[0050] S2: Add polystyrene resin and micron powder to step S1, heat to 110°C, stir for 60 min, cool to 40°C, and then add polymethyl methacrylate to obtain the modified product.

[0051] 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, magnesium olivine sand, pebbly sand and triacetyl ester are stirred and mixed for 20 seconds to obtain a powder mixture.

[0052] S4: Add the powder mixture to the sand mixing device, add the modifier from step S2 and mix for 20 seconds to obtain high-performance water glass ester hardened molding sand.

[0053] Example 2

[0054] A high-performance water glass ester hardened molding sand, in parts by weight, comprises the following raw materials: 80 parts calcium carbonate sand, 16 parts magnesium olivine sand, 8 parts granulated sand, 3 parts water glass solution, 1 part lithium hydroxide, 3 parts polystyrene resin, 2 parts polymethyl methacrylate, 0.4 parts micron powder, and 0.3 parts triacetyl ester.

[0055] The micron powder is a mixture of basic calcium carbonate, microsilica powder, and boron nitride in a ratio of 1.2:1.5:0.5.

[0056] The magnesium olivine sand has a magnesium oxide content of 48.29% and a particle size of 80 mesh.

[0057] The particle size of the agate sand is 40 mesh.

[0058] The method for preparing the micron powder is as follows: basic calcium carbonate, microsilica powder, and boron nitride are added to a ball mill according to the specified ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is 1.4:0.7, and the rotation speed of the ball mill is 200 r / min.

[0059] A method for preparing high-performance water glass ester hardened molding sand includes the following steps:

[0060] S1: Sonicate the water glass solution for 40 min, add lithium hydroxide to the sonicated water glass solution, heat to 90℃, stir for 40 min, and then cool to room temperature;

[0061] S2: Add polystyrene resin and micron powder to step S1, heat to 100°C, stir for 40 min, cool to 35°C, and then add polymethyl methacrylate to obtain the modified product.

[0062] 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, magnesium olivine sand, pebbly sand and triacetyl ester are stirred and mixed for 30 seconds to obtain a powder mixture.

[0063] S4: Add the powder mixture to the sand mixing device, add the modifier from step S2 and mix for 30 seconds to obtain high-performance water glass ester hardened molding sand.

[0064] Example 3

[0065] A high-performance water glass ester hardened molding sand, in parts by weight, comprises the following raw materials: 85 parts calcium carbonate sand, 17 parts magnesium olivine sand, 5 parts granulated sand, 3 parts water glass solution, 1 part lithium hydroxide, 3 parts polystyrene resin, 2 parts polymethyl methacrylate, 0.4 parts micron powder, and 0.3 parts triacetyl ester.

[0066] The micron-sized powder is a mixture of basic calcium carbonate, microsilica powder, and boron nitride in a ratio of 1.4:1.8:0.7.

[0067] The magnesium olivine sand has a magnesium oxide content of 52.62% and a particle size of 60 mesh.

[0068] The particle size of the agate sand is 60 mesh.

[0069] The method for preparing the micron powder is as follows: basic calcium carbonate, microsilica powder, and boron nitride are added to a ball mill according to the specified ratio, and then anhydrous ethanol is added and mixed. The ratio of micron powder to anhydrous ethanol is 1.3:0.8, and the rotation speed of the ball mill is 220 r / min.

[0070] A method for preparing high-performance water glass ester hardened molding sand includes the following steps:

[0071] S1: Sonicate the water glass solution for 45 min, add lithium hydroxide to the sonicated water glass solution, heat to 75°C, stir for 36 min, and then cool to room temperature.

[0072] S2: Add polystyrene resin and micron powder to step S1, heat to 105°C, stir for 55 min, cool to 35°C, and then add polymethyl methacrylate to obtain the modified product.

[0073] 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, magnesium olivine sand, pebbly sand and triacetyl ester are stirred and mixed for 50 seconds to obtain a powder mixture.

[0074] S4: Add the powder mixture to the sand mixing device, add the modifier from step S2 and mix for 50 seconds to obtain high-performance water glass ester hardened molding sand.

[0075] Example 4

[0076] A high-performance water glass ester hardened molding sand, in parts by weight, comprises the following raw materials: 90 parts calcium carbonate sand, 12 parts magnesium olivine sand, 6 parts granulated sand, 4 parts water glass solution, 1.5 parts lithium hydroxide, 2 parts polystyrene resin, 1 part polymethyl methacrylate, 0.3 parts micron powder, and 0.4 parts triacetyl ester.

[0077] The micron-sized powder is a mixture of basic calcium carbonate, microsilica powder, and boron nitride in a ratio of 1:1:0.1.

[0078] The magnesium olivine sand has a magnesium oxide content of 55.69% and a particle size of 80 mesh.

[0079] The particle size of the agate sand is 60 mesh.

[0080] The method for preparing the micron powder is as follows: basic calcium carbonate, microsilica powder, and boron nitride are added to a ball mill according to the specified 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 220 r / min.

[0081] A method for preparing high-performance water glass ester hardened molding sand includes the following steps:

[0082] S1: Sonicate the water glass solution for 45 min, add lithium hydroxide to the sonicated water glass solution, heat to 60°C, stir for 30 min, and then cool to room temperature;

[0083] S2: Add polystyrene resin and micron powder to step S1, heat to 110°C, stir for 60 min, cool to 40°C, and then add polymethyl methacrylate to obtain the modified product.

[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, magnesium olivine sand, granulated sand and triacetyl ester are stirred and mixed for 60 seconds to obtain a powder mixture.

[0085] S4: Add the powder mixture to the sand mixing device, add the modifier from step S2 and mix for 60 seconds to obtain high-performance water glass ester hardened molding sand.

[0086] Comparative Example 1

[0087] The preparation process is basically the same as that in Example 2, except that the raw materials for preparing high-performance water glass ester hardened molding sand lack polystyrene resin, polymethyl methacrylate, and micron powder.

[0088] Comparative Example 2

[0089] The preparation process is basically the same as that in Example 2, except that polystyrene resin is missing from the raw materials for preparing high-performance water glass ester hardened molding sand.

[0090] Comparative Example 3

[0091] The preparation process is basically the same as that in Example 2, except that polymethyl methacrylate is missing from the raw materials for preparing high-performance water glass ester hardened molding sand.

[0092] Comparative Example 4

[0093] The preparation process is basically the same as that in Example 2, except that the raw materials for preparing high-performance water glass ester hardened molding sand lack micron powder.

[0094] The high-performance water glass ester hardened molding sands prepared in Examples 1-4 and Comparative Examples 1-4 were subjected to strength and collapse tests. The higher the 2-hour strength and 24-hour strength of the molding sand, the better the bonding effect. The lower the residual compressive strength at 800℃, the higher the collapseability of the molding sand. The results are shown in the table below.

[0095]

[0096] As can be seen from the table above: (1) From the data of the molding sand of Examples 1-4 at 2h strength, 24h strength and residual strength at 800℃, it can be seen that the water glass ester hardened molding sand prepared by the method of the present invention has excellent strength and collapsibility, which can meet the application requirements in casting basic high manganese steel.

[0097] (2) As can be seen from the data of Example 2 and Comparative Examples 1-4, polystyrene resin, polymethacrylate, and micron-sized powder play a synergistic role in the preparation of high-performance water glass ester hardened molding sand, synergistically improving the immediate strength and collapsibility of the high-performance water glass ester hardened molding sand. This may be because:

[0098] This invention modifies water glass with polystyrene resin, making it easier for the water glass to adhere to the surface of the sand particles, thus improving its strength. Polymethyl methacrylate crosslinks the water glass and polystyrene resin, allowing them to interact during hardening to form shared bonding bridges and further enhancing the strength of the original water glass sand. Furthermore, at high temperatures, the polymethyl methacrylate decomposes to release gas, reducing the residual strength of the molding sand and improving its collapsibility. After modification with lithium hydroxide and polystyrene resin, the addition of organic components to the system improves the surface quality of the molding sand and alters the atmosphere during casting. The lithium hydroxide-polystyrene resin provides a reducing atmosphere for the molding sand system, controlling sand adhesion, preventing vein formation to some extent, significantly reducing residual strength, and simplifying sand cleaning. Micron-sized powders (calcium carbonate, silica fume, boron nitride) have a low coefficient of linear expansion. During the cooling process of molten water glass, micron-sized powder cracks are generated in the bonding bridge. At the same time, the micron-sized powder can uniformly coat the sand particles, making the water glass and sand particles tightly bonded, thereby improving the strength of the molding sand. Furthermore, the volatilization of polymethyl methacrylate causes the pores generated by the bonding bridge, which effectively improves the collapsibility of the molding sand.

[0099] 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 high-performance water glass ester hardened molding sand, characterized in that, The following raw materials are included in parts by weight: 70-90 parts calcium carbonate sand, 10-20 parts magnesium olivine sand, 5-10 parts granulated sand, 2-4 parts water glass solution, 0.8-1.5 parts lithium hydroxide, 2-4 parts polystyrene resin, 1-3 parts polymethyl methacrylate, 0.3-0.6 parts micron powder, and 0.2-0.6 parts triacetyl ester. The magnesium oxide content in the forsterite sand is 48.29%-58.61%, and the particle size is 40-80 mesh. The particle size of the agate sand is 40-100 mesh; The micron-sized powder is a mixture of basic calcium carbonate, microsilica powder, and boron nitride in a ratio of (1-1.5):(1-2):(0.1-0.8). The preparation method of the micron powder is as follows: basic calcium carbonate, microsilica powder and boron nitride 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):(0.5-1).

2. The high-performance water glass ester hardened molding sand according to claim 1, characterized in that, The following raw materials are included in parts by weight: 80 parts calcium carbonate sand, 16 parts magnesium olivine sand, 8 parts granulated sand, 3 parts water glass solution, 1 part lithium hydroxide, 3 parts polystyrene resin, 2 parts polymethyl methacrylate, 0.4 parts micron powder, and 0.3 parts triacetyl ester.

3. The high-performance water glass ester hardened molding sand according to claim 1, characterized in that, The micron-sized powder is a mixture of basic calcium carbonate, microsilica powder, and boron nitride in a ratio of 1.2:1.5:0.

5.

4. The high-performance water glass ester hardened molding sand according to claim 1, characterized in that, The ball mill rotates at a speed of 200-250 r / min.

5. A method of producing a high-performance sodium silicate ester hardened sand according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1: Sonicate the water glass solution for 30-60 minutes, add lithium hydroxide to the sonicated water glass solution, heat to 60-90℃, stir for 30-40 minutes, and then cool to room temperature; S2: Add polystyrene resin and micron powder to step S1, heat to 90-110℃, stir for 30-60 min, cool to 30-40℃, and then add polymethyl methacrylate to obtain the modified product. S3: Grind the raw materials into powder with a particle size greater than 40 mesh by crushing and ball milling. According to the weight parts of the formula, stir and mix calcium carbonate sand, magnesium olivine sand, granulated sand and triacetyl ester for 20-60 seconds to obtain a powder mixture. S4: Add the powder mixture to the sand mixing device, add the modifier from step S2 and mix for 20-60 seconds to obtain high-performance water glass ester hardened molding sand.

6. The method of producing high performance sodium silicate ester hardened sand according to claim 5, characterized by, In step S2, polystyrene resin and micron powder are added to step S1, heated to 100°C, stirred for 40 minutes, cooled to 35°C, and then polymethyl methacrylate is added.

7. An application of the high-performance water glass ester hardened molding sand according to claim 1, characterized in that, The high-performance water glass ester hardened molding sand is used for casting alkaline high manganese steel.

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