Inner wall thermal insulation material for continuous casting process device and preparation method of inner wall thermal insulation material

Abstract

The invention provides an inner wall thermal insulation material for a continuous casting process device and a preparation method. An inner wall thermal insulation material for a continuous casting process device is prepared from the following components in parts by mass: 40 to 50 parts of aluminum oxide, 20 to 25 parts of hollow ceramic microbeads, 5 to 10 parts of a three-dimensional woven preform, 5 to 8 parts of nano zirconium oxide, 3 to 5 parts of fluorinated modified SiO2 aerogel and 2 to 3 parts of Y2O3-La2O3 composite rare earth oxide, the contact angle of the fluorinated modified SiO2 aerogel is greater than or equal to 160 degrees. The thermal insulation material provided by the invention has an ultralow heat conductivity coefficient which does not exceed 0.06 W / m.K at room temperature and does not exceed 0.10 W / m.K at 1000 DEG C; high thermal shock resistance: no cracking is generated after water cooling circulation at 1300 DEG C to room temperature for more than or equal to 50 times; the contact angle is larger than or equal to 160 degrees, and the water absorption rate is smaller than or equal to 1%; and the interface bonding strength is greater than or equal to 20MPa.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of thermal insulation materials, and particularly relates to an inner wall thermal insulation material for a continuous casting process device and a preparation method. BACKGROUND

[0002] The continuous casting process is a key link in steel production, and the performance of the inner wall thermal insulation material of key equipment in the continuous casting process, such as a continuous casting tundish nozzle roasting device, directly affects the nozzle preheating efficiency and energy consumption.

[0003] At present, the refractory material commonly used in the continuous casting tundish has certain limitations, such as limited thermal insulation effect, which leads to a large temperature drop of molten steel. In the field, nano thermal insulation materials are used to improve the thermal insulation effect, but the thermal insulation effect is still not ideal. The prior art still has the following problems:

[0004] 1. Insufficient thermal insulation performance: the traditional high-alumina refractory material (such as the disclosed Al2O3-based material) has a high thermal conductivity coefficient (>0.3 W / m·K), which leads to serious heat loss and uneven roasting temperature.

[0005] 2. High risk of falling off: the existing binder (such as phosphate) has poor high-temperature stability, and the thermal expansion coefficients of the material interfaces are greatly different, which easily causes delamination and falling off due to thermal stress.

[0006] 3. Short service life: insufficient thermal shock resistance, and frequent thermal cycles lead to crack propagation. SUMMARY

[0007] Therefore, the purpose of the present application is to provide a high-performance inner wall thermal insulation material for a continuous casting process device and a preparation method, to improve the thermal insulation performance and interface bonding strength, and to meet relevant international standards.

[0008] The present application provides an inner wall thermal insulation material for a continuous casting process device, which comprises the following components in terms of mass fraction:

[0009]

[0010] The contact angle of the fluorinated modified SiO2 aerogel is ≥160°.

[0011] Preferably, the particle size of the alumina is ≤5 μm.

[0012] Preferably, the fiber diameter of the three-dimensional woven preform is ≤5 μm.

[0013] Preferably, the three-dimensional woven preform is a silicon carbide / alumina three-dimensional woven preform.

[0014] Preferably, the particle size of the nano zirconia is 30-50 nm.

[0015] Preferably, Y / La of the Y2O3-La2O3 composite rare earth oxide is 1:1.

[0016] A composite thermal insulation material, comprising any of the above-mentioned inner wall thermal insulation materials, further comprising a SiC-Al2O3 coating and a Y2O3 coating.

[0017] A method for preparing any of the above-mentioned inner wall thermal insulation materials, comprising the following steps:

[0018] (1) Pretreatment of raw materials:

[0019] ball-milling the alumina and the hollow ceramic microbeads to D90≤5μm,

[0020] Preparation of the fluorinated modified SiO2 aerogel v Aerogel: the SiO2 aerogel is immersed in an ethanol solution of perfluorodecyltrimethoxysilane with a mass fraction of 5% to 8% for 2 to 4 hours, and after drying, the contact angle is ≥160°; v Aerogel: the SiO2 aerogel is immersed in an ethanol solution of perfluorodecyltrimethoxysilane with a mass fraction of 5% to 8% for 2 to 4 hours, and after drying, the contact angle is ≥160°;

[0021] (2) Mixing and molding:

[0022] The alumina, the hollow ceramic microbeads, the nano-zirconium oxide, and the Y2O3-La2O3 composite rare earth oxide are added into a binder and stirred for 30 to 60 minutes, then the fluorinated modified SiO2 aerogel and the three-dimensional woven preform are added, ultrasonic dispersion is performed for 15 to 30 minutes, the mold is vibrated and degassed, and room temperature curing is performed.

[0023] (3) Gradient drying and sintering:

[0024] Gradient drying is performed, sintering is performed under a N2 / H2 / CH4 atmosphere, and a thermal insulation material is obtained.

[0025] Preferably, the binder comprises silica sol and / or aluminum dihydrogen phosphate. When silica sol and aluminum dihydrogen phosphate are selected as the binder, the mass ratio of the two is 1:1 to 1:3.

[0026] Preferably, the sintering process is heated at a rate of 3 to 8℃ / min to 1550 to 1600℃, and the temperature is maintained for 1.5 to 3 hours.

[0027] Compared with the prior art, the application has the following beneficial effects:

[0028] The thermal insulation material has an ultra-low thermal conductivity: not more than 0.06 W / m·K at room temperature and not more than 0.10 W / m·K at 1000℃; high thermal shock resistance: no cracking after 1300℃ to room temperature water cooling cycle for 50 times; super-hydrophobic property: contact angle ≥160°, water absorption rate ≤1%; interface bonding strength: ≥20 MPa (in line with ASTM D3165 standard). The thermal insulation material is very suitable for continuous casting process device, solves the problems existing in the prior art, ensures smooth pouring, and does not affect the quality of the billet.

[0029] The composite thermal insulation material has the advantages of strong thermal expansion matching, resistance to molten steel scouring, and high service life.

[0030] The preparation method can prepare high-performance thermal insulation material with high interface bonding strength and high process stability. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only some of the embodiments of the present application, not all. If specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used.

[0032] An inner wall thermal insulation material for a continuous casting process device, comprising the following components in parts by mass:

[0033] Alumina 40-50 parts, which can be 40 parts, 45 parts, 50 parts, etc.,

[0034] Hollow ceramic microbeads 20-25 parts, which can be 20 parts, 22 parts, 25 parts, etc.,

[0035] Three-dimensional woven preform 5-10 parts, which can be 5 parts, 8 parts, 10 parts, etc.,

[0036] Nano-zirconia 5-8 parts, which can be 5 parts, 7 parts, 8 parts, etc.,

[0037] Fluorinated modified SiO2 aerogel 3-5 parts, which can be 3 parts, 4 parts, 5 parts, etc.,

[0038] Y2O3-La2O3 composite rare earth oxide 2-3 parts, which can be 2 parts, 2.5 parts, 3 parts, etc.

[0039] The contact angle of the fluorinated modified SiO2 aerogel is ≥160°, which has the effect of blocking the penetration of water molecules and inhibiting the condensation of high-temperature silicon hydroxyl groups.

[0040] The fiber diameter of the three-dimensional woven preform is ≤5 μm. The three-dimensional woven preform is a carbon-based composite material, preferably a silicon carbide / alumina three-dimensional woven preform.

[0041] Y2O3-La2O3 composite rare earth oxide Y / La = 1:1.

[0042] A composite thermal insulation material, comprising any of the above-mentioned inner wall thermal insulation material, further comprising a SiC-Al2O3 coating and a Y2O3 stabilized ZrO2 coating. The inner layer is sprayed with a SiC-Al2O3 coating with a thickness of 0.05-0.15mm, and the outer layer is sprayed with a Y2O3 stabilized ZrO2 coating with a thickness of 0.15-0.25mm. The intermediate coating has a thickness of 20-50mm.

[0043] Example 1

[0044] An inner wall thermal insulation material for a continuous casting process device, comprising the following components:

[0045]

[0046] The contact angle of the fluorinated modified SiO2 aerogel is ≥160°.

[0047] The preparation method of the thermal insulation material in this embodiment is as follows:

[0048] (1) Raw material pretreatment:

[0049] Alumina and hollow ceramic microbeads are ball milled to a particle size ≤5μm.

[0050] Preparation of fluorinated modified SiO2 aerogel: SiO2 aerogel is immersed in a perfluorodecyltrimethoxysilane / ethanol solution (mass fraction 5%), and after drying, the contact angle is ≥160°.

[0051] (2) Mixing and molding:

[0052] Alumina, hollow ceramic microbeads, nano-zirconia, and Y2O3-La2O3 composite rare earth oxide are added to the silica sol and stirred for 30 minutes, then fluorinated modified SiO2 aerogel and silicon carbide / alumina three-dimensional woven preforms are added, ultrasonic dispersion is performed at a frequency of 60kHz for 15 minutes, the mold is injected and shaken to exhaust, and room temperature curing is performed for 24 hours.

[0053] (3) Gradient drying and sintering:

[0054] Gradient drying, 50℃×8h→150℃×4h→300℃×2h (heating rate ≤3℃ / min).

[0055] Sintering atmosphere: N2 / H2 / CH4 = 97 / 3 / 0.5, heated to 1550℃ at a rate of 5℃ / min, and held for 2 hours to obtain the thermal insulation material.

[0056] Example 2

[0057] A composite thermal insulation material comprising the inner wall thermal insulation material of Example 1, a coating thickness of 30 mm, further comprising a SiC-Al2O3 coating layer sprayed on the inner layer, a thickness of 0.1 mm, and a Y2O3 coating layer sprayed on the outer layer, a thickness of 0.2 mm.

[0058] Comparative Example 1

[0059] A thermal insulation material comprising the following components: inorganic microbeads 60 parts, silica sol 25 parts, common SiO2 aerogel 5 parts, and Y2O3 powder 2 parts.

[0060] Comparative Example 2

[0061] A thermal insulation material comprising the same components as Example 1.

[0062] The preparation method of the thermal insulation material of the present comparative example is as follows:

[0063] Step (1) and step (2) are the same as step (1) and step (2) of Example 1.

[0064] (3) Gradient drying and sintering:

[0065] Gradient drying, 50℃×8h→150℃×4h→300℃×2h (heating rate ≤3℃ / min).

[0066] Sintering atmosphere: N2 / H2=97 / 5, heating to 1550℃ at a rate of 5℃ / min, holding for 2 hours to obtain the thermal insulation material.

[0067] The thermal insulation materials of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 were sampled and tested, including thermal conductivity, thermal shock resistance, contact angle, comprehensive strength, and shrinkage, etc., and the results are shown in Table 1.

[0068] Table 1

[0069]

[0070] The results of Table 1 show that the thermal insulation materials of the present application have ultra-low thermal conductivity, high thermal shock resistance, super-hydrophobicity, low shrinkage, and excellent interfacial bonding strength, and are very suitable for continuous casting process production environment.

[0071] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A heat-insulating material for the inner wall of a continuous casting process apparatus, characterized in that, By mass, it includes the following components: The contact angle of the fluorinated modified SiO2 aerogel is ≥160°.

2. The inner wall insulation material according to claim 1, characterized in that, The alumina has a particle size ≤ 5 μm.

3. The inner wall insulation material according to claim 1, characterized in that, The fiber diameter of the three-dimensional woven preform is ≤5μm.

4. The inner wall insulation material according to claim 1, characterized in that, The three-dimensional braided preform is a silicon carbide / alumina three-dimensional braided preform.

5. The inner wall insulation material according to claim 1, characterized in that, The particle size of the nano-zirconia is 30–50 nm.

6. The inner wall insulation material according to claim 1, characterized in that, The Y / La ratio of the Y2O3-La2O3 composite rare earth oxide is 1:

1.

7. A composite thermal insulation material, characterized in that, The material includes the inner wall insulation material as described in any one of claims 1 to 6, and further includes a SiC-Al2O3 coating and a Y2O3 coating.

8. The method for preparing the inner wall insulation material according to any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Raw material pretreatment: The alumina and the hollow ceramic microspheres were ball-milled until D90 ≤ 5 μm. Preparation of the fluorinated modified SiO2 aerogel: The SiO2 aerogel was immersed in an ethanol solution of 5% to 8% perfluorodecyltrimethoxysilane for 2 to 4 hours, and after drying, the contact angle was ≥160°. (2) Mixing and molding: The alumina, hollow ceramic microspheres, nano-zirconia and Y2O3-La2O3 composite rare earth oxides are added to the binder and stirred for 30-60 minutes. Then the fluorinated modified SiO2 aerogel and the three-dimensional woven preform are added, ultrasonically dispersed for 15-30 minutes, injected into the mold, vibrated to degas, and cured at room temperature. (3) Gradient drying and sintering: Gradient drying is performed, followed by sintering under a N2 / H2 / CH4 atmosphere to obtain the thermal insulation material.

9. The preparation method according to claim 8, characterized in that, The binder includes silica sol and / or aluminum dihydrogen phosphate.

10. The preparation method according to claim 8, characterized in that, The sintering process involves heating to 1550–1600℃ at a rate of 3–8℃ / min and holding at that temperature for 1.5–3 hours.

Images