A ceramic filter housing for metal casting, material formula and preparation method thereof

Abstract

The invention relates to the technical field of casting auxiliary materials, and provides a ceramic filter housing for metal casting, a material formula and a preparation method. The material formula comprises, by weight, 25 to 70 parts of aggregate, 15 to 50 parts of matrix powder, 0 to 20 parts of micropowder, 0 to 12 parts of binder, 0 to 0.5 parts of fiber material, and 0 to 3 parts of active auxiliary agent; the aggregate is fused white corundum; the matrix aggregate is one or more of white corundum powder and silicon carbide powder; the micropowder is one or more of Al2O3 powder and microsilicon powder; the binder is an aluminate binder; the fiber material is polypropylene fiber; the active auxiliary agent is polyphosphate, sodium silicate, and polyacrylamide; and 0-12 parts of water are also included. The product has the excellent properties of high refractoriness, high compressive strength, low gas evolution, and good thermal shock resistance at 1600°C, meets the load-bearing capacity of heavy molten metal, solves the problem of molten metal filtering in the pouring process of large castings, and improves the quality of castings.

Description

Technical Field

[0001] The invention belongs to the field of casting auxiliary materials, and more specifically, relates to a material formula, a preparation process and a filter housing for metal casting. Background Art

[0002] The ceramic filter housing of the metal casting process is mainly used as a metal casting process, connected to the runner for draining the molten metal and fixing the molten metal filter plate, which allows the molten metal to pass through the filter plate smoothly, plays the role of filtering the impurities of the molten metal and completing the casting. However, in the metal casting process, the casting environment temperature is usually above 1600℃. Due to the high temperature of the molten metal, the existing filter housing product indicators cannot meet the performance requirements of casting auxiliary materials. There are problems with the performance of existing product indicators. Its compressive strength is about 40Mpa, which cannot withstand the drainage of heavy molten steel; the gas emission at 850℃ is ≥7ml / g, which is easy to cause pores, splashing and other problems in the metal casting process; after being washed by 1600℃ molten steel, it is severely eroded, so that more impurities enter the cast product, and the filtering effect cannot be achieved. Poor high temperature resistance, high gas emission, inability to meet the 1600℃ molten steel washing strength, and product indicators that do not meet the steel casting performance requirements need to be solved urgently. Summary of the invention

[0003] Based on this, the purpose of the present invention is to overcome the problems of low filtration volume, poor effect and high usage of ceramic filter housings for metal casting in the prior art. The present invention provides a ceramic filter housing suitable for metal casting process. After being matched with corresponding filter plates, it has the advantages of large filtration area, excellent residue filtration capacity and good filtration effect. It solves the problem that larger castings require too many filters during the pouring of molten metal and improves the quality of castings.

[0004] One of the objects of the present invention is to provide a material formula for a ceramic filter housing for metal casting.

[0005] A second object of the present invention is to provide a method for preparing a ceramic filter housing for metal casting.

[0006] The third object of the present invention is to provide a ceramic filter housing for metal casting based on material formulation and preparation method.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A material formula for a ceramic filter housing for metal casting, characterized in that it comprises the following components in parts by weight:

[0009] 25-70 parts of aggregate, 15-50 parts of matrix powder, 0-20 parts of fine powder, 0-12 parts of binder, 0-0.5 parts of fiber material, 0-3 parts of active additive;

[0010] The aggregate is fused white corundum;

[0011] The matrix aggregate is one or more of white corundum powder and silicon carbide powder;

[0012] The micro powder is Al 2 O 3 One or more of powder and microsilica fume;

[0013] The binder is an aluminate binder;

[0014] The fiber material is polypropylene fiber;

[0015] The active additives are polyphosphate, sodium silicate and polyacrylamide;

[0016] Also included is 0-12 parts of water.

[0017] In one embodiment, the fused white corundum is one or more of 8-5mm fused white corundum, 5-3mm fused white corundum, 3-1mm fused white corundum, and 1-0mm fused white corundum. Different particle sizes are selected according to the thickness of the product to ensure the molding performance of the product. At the same time, selecting different particle sizes can achieve the best filling density and increase the strength of the product.

[0018] In one embodiment, according to the weight percentage, the amount of the 8-5mm fused white corundum is 0 to 30 parts; the amount of the 5-3mm fused white corundum is 10 to 40 parts; the amount of the 3-1mm fused white corundum is 10 to 30 parts; and the amount of the 1-0mm fused white corundum is 10 to 25 parts.

[0019] In one embodiment, the white corundum powder is 325-400 mesh white corundum powder or 100-200 mesh white corundum powder; the silicon carbide powder is 325-400 mesh silicon carbide powder.

[0020] In one embodiment, in terms of weight, the amount of the 100-200 mesh white corundum powder is 5-20 parts; the amount of the 325-400 mesh white corundum powder is 5-25 parts; and the amount of the 325-400 mesh silicon carbide powder is 4-16 parts.

[0021] In one embodiment, the Al 2 O 3 Powder is 2500~6250 mesh Al 2 O 3 Powder, 6250~12500 mesh Al2 O 3 Powder; the microsilica powder is 2500-6250 mesh microsilica powder.

[0022] In one embodiment, the 2500-6250 mesh Al 2 O 3 The number of powders is 0 to 8; the 6250 to 12500 mesh Al 2 O 3 The amount of powder is 0 to 4 parts; the amount of 2500 to 6250 mesh microsilica powder is 0 to 8 parts.

[0023] In one embodiment, the aluminate binder is a calcium aluminate binder.

[0024] A method for preparing a ceramic filter housing for metal casting, characterized in that it comprises the following steps: S1: weighing aggregate, matrix powder, micropowder, binder, fiber material and active additive and adding them into a mixer for mixing and stirring for 10 to 30 minutes;

[0025] S2: adding water and stirring for 2 to 8 minutes;

[0026] S3: Pour the mixed material into the product mold and vibrate it for 30-300 seconds;

[0027] S4: After the molding is completed, the product is cured for 24 to 72 hours. The curing conditions are relative temperature 0 to 40°C and relative humidity 40 to 100%;

[0028] S5: heating to 100-160° C. for pre-drying for 24 to 48 hours, heating to 1100° C. for keeping warm for 3 to 10 hours; obtaining the ceramic filter housing for metal casting.

[0029] A ceramic filter housing for metal casting is prepared according to a material formula and a preparation method of the ceramic filter housing for casting.

[0030] The beneficial effects of the present invention are:

[0031] The present invention adjusts the ratio of alumina, microsilica powder, and fused white corundum in the powder, which is equivalent to adjusting the molar ratio of Al and Si elements in the material, so that it generates more mullite phases and enhances the high-temperature performance of the product. By determining the ratio of microsilica powder, the water absorption and anti-shrinkage and expansion performance of the product are improved, and the cracks in the product during production and use are reduced. By adding polypropylene fiber, the exhaust property of the product during the molding process and the toughness of the product at room temperature are improved, making it less likely to break, and exhaust holes are formed during the sintering process to facilitate the discharge of water vapor during the sintering process and reduce the cracking phenomenon caused by water vapor during sintering. The binder of the present invention uses an aluminate binder, and through the hydration reaction mechanism at low temperature and the solid solution reaction mechanism at high temperature, the product has the effect of ensuring its strength at any temperature below 1600°C. In addition, the raw materials of the present invention are selected from inorganic materials, and the high temperature resistance is more excellent. The refractoriness of the product of the present invention is ≥1800℃, which solves the problem that traditional castables cannot be used for high-temperature molten metal pouring, fully meets the use temperature of the casting environment of 1600℃, is used in the metal pouring process, and can withstand the scouring of high-temperature molten metal. By adding powders such as silicon carbide, the powders are combined through high temperature to form a solid solution phase containing silicon carbide, thereby improving the thermal shock resistance of the product and solving the thermal shock resistance of the ceramic filter housing suitable for the metal casting process during the metal pouring process. The number of thermal shock resistance at 1600℃ is ≥1 time, and it can withstand the rapid heat damage caused to the product by the molten metal during the pouring process. The product of the present invention has a relatively high compressive strength, reaching a compressive strength of 80Mpa, which meets the load-bearing requirements of heavy molten metal.

[0032] In the present invention, sodium tripolyphosphate and sodium hexametaphosphate are added to reduce the water content and gas emission after the product is formed, and the pores and splashing defects caused by the gas emission in metal casting are reduced; polyacrylamide is added to increase the viscosity during the product molding process, so that the internal material maintains uniformity in all positions during vibration molding, and stabilizes its high-temperature corrosion resistance; sodium silicate is added to control the condensation reaction rate of the product, and the bonding strength at room temperature is improved, and a certain strength support is provided at high temperature. The present invention has low gas emission, 850°C gas emission ≤7ml / g, and the lowest gas emission that can be detected can reach 1.17ml / g, which reduces the gas emission during the casting process, eliminates pores, and pouring splashing defects.

[0033] The product of the present invention has a significant effect on improving the quality of large castings that require molten metal impurities filtering and reducing the impurity content; it is simple to make and easy to shape, and the finished product can be stored for a long time; no harmful substances are generated during the production process of the present invention, which is beneficial to environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] none DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Specific embodiment 1:

[0037] This embodiment provides a material formula for a ceramic filter housing for metal casting, which includes 56 parts of aggregate by weight; the powder includes 28 parts of matrix powder, 9 parts of micro powder, 5.5 parts of calcium aluminate binder, 0.5 parts of polypropylene fiber, 0.68 parts of active auxiliary agent and 7 parts of water by weight;

[0038] The aggregates weighed include: 18 parts by weight of 8-5mm fused white corundum, 16 parts by weight of 5-3mm fused white corundum, 12 parts by weight of 3-1mm fused white corundum, and 10 parts by weight of 1-0mm fused white corundum;

[0039] The matrix powder comprises: 14 parts by weight of 100-200 mesh white corundum powder, 6 parts by weight of 325-400 mesh white corundum powder, and 8 parts by weight of 325-400 mesh silicon carbide powder;

[0040] Micro powder includes: 5 parts by weight of 2500-6250 mesh Al 2 O 3 Powder, 2 parts by weight of 6250-12500 mesh Al 2 O 3 Powder, 2 parts by weight of 2500-6250 mesh microsilica powder;

[0041] The active binder comprises: 0.14 parts by weight of sodium tripolyphosphate, 0.14 parts by weight of sodium hexametaphosphate, 0.2 parts by weight of sodium silicate, and 0.2 parts by weight of polyacrylamide.

[0042] A method for preparing a ceramic filter housing for metal casting is provided, and the specific steps are as follows:

[0043] S1: Add aggregate and powder into a mixer and mix them for 8 minutes until the powder and aggregate are in a uniform state;

[0044] S2: adding 7 parts by weight of water to the mixed powder and aggregate and stirring for 5 minutes;

[0045] S3: Pour the mixed material into the product mold and vibrate it for 150 seconds;

[0046] S4: After the molding is completed, the product is cured at 25°C and 60% relative humidity for 48 hours;

[0047] S5: Heat to 115℃ for pre-drying for 24 hours, heat to 1100℃ for 6 hours;

[0048] The ceramic filter housing for metal casting is obtained. Specific embodiment 2:

[0050] This embodiment provides a material formula for a ceramic filter housing for metal casting, which includes 60 parts by weight of aggregate and powder; the powder includes 12 parts of matrix powder, 11.5 parts of micro powder, 5.5 parts of calcium aluminate binder, 0.5 parts of polypropylene fiber, 0.2 parts of active auxiliary agent and 7 parts by weight of water;

[0051] The aggregate weighed includes: 28 parts by weight of 5-3 mm fused white corundum, 22 parts by weight of 3-1 mm fused white corundum, and 10 parts by weight of 1-0 mm fused white corundum;

[0052] The matrix powder comprises: 6 parts by weight of 100-200 mesh white corundum powder, 6 parts by weight of 325-400 mesh white corundum powder, and 8 parts by weight of 325-400 mesh silicon carbide powder;

[0053] Micro powder includes: 3.5 parts by weight of 2500-6250 mesh Al 2 O 3 Powder, 8 parts by weight of 2500-6250 mesh microsilica powder;

[0054] The active binder includes: 0.2 parts by weight of sodium tripolyphosphate.

[0055] A method for preparing a ceramic filter housing for metal casting is provided, and the specific steps are as follows:

[0056] S1: Add the above aggregate and the above powder into a mixer and mix and stir for 6 minutes;

[0057] S2: Mix the mixed powder and aggregate and add 7 parts by weight of water and stir for 5 minutes;

[0058] S3: Pour the mixed materials into the product mold and vibrate them for 120 seconds;

[0059] S4: After the molding is completed, the product is cured at 25°C and 60% relative humidity for 36 hours;

[0060] S5: Heat to 115℃ for pre-drying for 24 hours, heat to 1100℃ for 5 hours;

[0061] The ceramic filter housing for metal casting is obtained.

[0062] The ceramic filter housing for metal casting prepared in the above embodiment was subjected to performance testing and actual application for multiple times to conduct effect evaluation experiments. The filter housing made of this material was used for casting steel castings and iron castings. During the casting process, the temperatures of the pouring liquid were 1580°C and 1380°C, respectively, which met the load-bearing capacity of the heavy metal liquid. There were no problems such as pores and splashing in the metal casting process. The filter housing could withstand the flushing of the metal liquid and had a good filtering effect, thereby improving the quality of the castings.

[0063] The filter housing has good performance and has a significant effect on improving the quality and reducing the impurity content of large castings that require molten metal impurities filtration. The performance test results of the products obtained in the implementation case are summarized as follows:

[0064] performance Refractoriness Compressive strength Gas volume 1600℃ thermal shock resistance Implementation Case 1 1800℃ 81Mpa 1.1ml / g ≥1 time Implementation Case 2 1800℃ 86Mpa 1.1ml / g ≥1 time

[0065] It can be seen from the table that the filter housing of the present invention has high compressive strength, excellent high temperature performance, high refractoriness, can reduce the amount of gas generated during the casting process and withstand the weight of large-weight molten metal.

[0066] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A material formula for a ceramic filter housing for metal casting, characterized in that: The composition comprises the following components by weight: 25 to 70 parts of aggregate, 15 to 50 parts of matrix powder, 0 to 20 parts of fine powder, 0 to 12 parts of binder, 0 to 0.5 parts of fiber material, and 0 to 3 parts of active additive; The aggregate is fused white corundum; The matrix aggregate is one or more of white corundum powder and silicon carbide powder; The micro powder is one or more of Al2O3 powder and micro silicon powder; The binder is an aluminate binder; The fiber material is polypropylene fiber; The active additives are polyphosphate, sodium silicate and polyacrylamide; Also included is 0-12 parts of water.

2. The material formula of a ceramic filter housing for metal casting according to claim 1, characterized in that: The fused white corundum is one or more of 8-5mm fused white corundum, 5-3mm fused white corundum, 3-1mm fused white corundum and 1-0mm fused white corundum.

3. The material formula of a ceramic filter housing for metal casting according to claim 2, characterized in that: In terms of weight, the 8-5mm fused white corundum is 0 to 30 parts; the 5-3mm fused white corundum is 10 to 40 parts; the 3-1mm fused white corundum is 10 to 30 parts; and the 1-0mm fused white corundum is 10 to 25 parts.

4. The material formula of a ceramic filter housing for metal casting according to claim 1, characterized in that: The white corundum powder is 325-400 mesh white corundum powder or 100-200 mesh white corundum powder; the silicon carbide powder is 325-400 mesh silicon carbide powder.

5. The material formula of a ceramic filter housing for metal casting according to claim 4, characterized in that: In terms of weight, the amount of the 100-200 mesh white corundum powder is 5-20 parts; the amount of the 325-400 mesh white corundum powder is 5-25 parts; and the amount of the 325-400 mesh silicon carbide powder is 4-16 parts.

6. The material formula of a ceramic filter housing for metal casting according to claim 1, characterized in that: The Al2O3 powder is 2500-6250 mesh Al2O3 powder or 6250-12500 mesh Al2O3 powder; the microsilica powder is 2500-6250 mesh microsilica powder.

7. The material formula of a ceramic filter housing for metal casting according to claim 6, characterized in that: In terms of weight proportions, the proportion of the 2500-6250 mesh Al2O3 powder is 0-8 proportions; the proportion of the 6250-12500 mesh Al2O3 powder is 0-4 proportions; and the proportion of the 2500-6250 mesh microsilica powder is 0-8 proportions.

8. The material formula of a ceramic filter housing for metal casting according to claim 1, characterized in that: The aluminate binder is a calcium aluminate binder.

9. A method for preparing a ceramic filter housing for metal casting, characterized in that: The following steps are involved: S1: weigh aggregate, matrix powder, micro powder, binder, fiber material and active additive and add them into a mixer for mixing and stirring for 10 to 30 minutes; S2: adding water and stirring for 2 to 8 minutes; S3: Pour the mixed material into the product mold and vibrate it for 30-300 seconds; S4: After the molding is completed, the product is cured for 24 to 72 hours. The curing conditions are relative temperature 0 to 40°C and relative humidity 40 to 100%; S5: Heat to 100-160℃ for pre-drying for 24-48 hours, heat to 1100℃ and keep warm for 3-10 hours; The ceramic filter housing for metal casting is obtained.

10. A ceramic filter housing for metal casting, characterized in that: The ceramic shell for metal casting is a ceramic shell for metal casting prepared according to the material formula and preparation method of the ceramic filter shell for casting according to any one of claims 1 to 9.