Tundish with oxygen blocking function for ultra-pure steel smelting

Abstract

The utility model discloses a tundish with oxygen barrier function for ultra-pure steel smelting, which sequentially comprises a tundish shell (1), a thermal insulation layer (2), a permanent layer (3), a working layer (4) and an oxygen barrier coating (5) from outside to inside, the thermal insulation layer (2) is laid on the inner surface of the tundish shell (1), the permanent layer (3) is poured on the surface of the thermal insulation layer (2), the working layer (4) is coated or sprayed on the surface of the permanent layer (3), and the oxygen barrier coating (5) is coated or sprayed on the surface of the working layer (4). And the oxygen barrier coating (5) is adhered to the surface of the working layer (4) in a smearing or spraying manner. The utility model has the advantages that the oxygen permeation is effectively prevented, the generation of inclusions is reduced, and the inclusions are adsorbed, so that the cleanliness of molten steel is improved, and the quality of steel billets is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of refractory materials for continuous casting, in particular to a tundish for smelting ultrapure steel with an oxygen barrier function. Background Art

[0002] As the intermediate link between steelmaking and steel rolling, continuous casting is the key link in molten steel quality control. With the rapid development of metallurgical technology, higher requirements are put forward for the function of tundish to remove inclusions.

[0003] The traditional lining of the tundish is mostly composed of three parts, namely the insulation layer, the permanent layer castable, and the dry material or coating material. Magnesium coating material is mostly used as the working lining for casting high-quality steel. The magnesium coating material is stirred by adding water, and after stirring evenly, it is applied to the surface of the permanent layer by coating or spraying. However, since the magnesium coating material contains a large amount of water, the water in the coating material will evaporate in large quantities during the baking process of the tundish, resulting in a relatively loose internal structure of the magnesium coating material and a large porosity. The large number of pores will become the oxygen supply channel during the continuous casting process of the tundish. O2 in the atmosphere is enriched on the inner surface of the magnesium coating material and will react with Fe and Mn in the molten steel to form FeO and MnO. FeO and MnO are extremely oxidizing, and they will react with SiO2 in the coating material to produce 2FeO•SiO2, namely fayalite, and MnO•SiO2, namely manganese silicate. The melting points of these two substances are 1205℃ and 1270℃. However, the temperature of the continuous casting molten steel is 1500~1550℃, and the low-melting-point substances generated will become oxide inclusions and be drawn into the molten steel, and then brought into the ingot by the molten steel, thus affecting the quality of the ingot. Utility Model Content

[0004] The utility model aims to solve the problem that the chemical properties of the existing tundish coating are unstable and easy to react, resulting in poor quality of the steel billet. It provides a tundish for smelting ultra-pure steel with an oxygen barrier function, which can effectively prevent oxygen from penetrating, reduce the generation of inclusions, and adsorb inclusions, thereby improving the cleanliness of molten steel and ensuring the quality of the steel billet.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A tundish for smelting ultrapure steel with an oxygen-barrier function comprises, from the outside to the inside, a cladding, an insulating layer, a permanent layer, a working layer and an oxygen-barrier coating. The insulating layer is laid on the surface of the cladding, the permanent layer is poured on the surface of the insulating layer, the working layer is then coated or sprayed on the surface of the permanent layer, and the oxygen-barrier coating is then adhered to the surface of the working layer by coating or spraying.

[0007] Furthermore, the thermal insulation layer and the cladding are bonded together by a high-temperature bonding agent.

[0008] Furthermore, the thermal insulation layer is a nano-silicon dioxide thermal insulation board, the laying thickness of which is 5-10 mm, and the thermal conductivity is less than 0.02 W / (m·K).

[0009] Furthermore, the permanent layer is a silica sol-bonded castable material, with a casting thickness of about 80-160 mm, a thermal conductivity of less than 0.2 W / (m·K), a water-cooled thermal shock of more than 30 times, and a high-temperature flexural strength of more than 3 Mpa at 1500°C.

[0010] Furthermore, the casting thickness of the permanent layer is 80-140 mm.

[0011] Furthermore, the material of the permanent layer is corundum-mullite.

[0012] Furthermore, the working layer is a magnesium coating material, and the coating thickness is 60-100 mm.

[0013] Furthermore, the oxygen barrier coating is a corundum refractory material, and its coating thickness is 40-60 mm.

[0014] Compared with the prior art, the advantages of the technical solution of the utility model are specifically:

[0015] (1) The utility model adds an oxygen barrier coating to the traditional tundish structure. The oxygen barrier coating forms a sintered layer at high temperature. This sintered layer isolates most of the O2 in the atmosphere from penetrating into the molten steel, thereby reducing the generation of FeO and MnO, and further slowing down the reaction of FeO, MnO and SiO2 to generate oxide inclusions;

[0016] (2) The sintered layer of the utility model has a microporous structure, which can effectively absorb inclusions in molten steel and reduce molten steel inclusions;

[0017] (3) The oxygen barrier coating of the utility model is made of corundum, and Al2O3 will not react with FeO and MnO in the molten steel to form low-melting products. The tundish with oxygen barrier function can not only effectively block the infiltration of most O2, but also effectively reduce inclusions and improve the cleanliness of the molten steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The utility model is a schematic diagram of the structure of the lining of the tundish for smelting ultrapure steel with oxygen barrier function. DETAILED DESCRIPTION Example

[0019] In order to make the present invention more clear, the present invention is further described below with reference to the accompanying drawings as an example of a tundish for smelting ultrapure steel with oxygen barrier function. The specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0020] See also Figure 1 , a tundish for ultrapure steel smelting with oxygen barrier function, characterized in that:

[0021] It includes, from outside to inside, a cladding 1, a thermal insulation layer 2, a permanent layer 3, a working layer 4 and an oxygen barrier coating 5;

[0022] The insulation layer 2 is made of nano-silicon dioxide material, and the insulation layer 2 and the cladding 1 are bonded together by a high-temperature bonding agent;

[0023] The permanent layer 3 is a corundum-mullite silica sol castable material, which has high hot strength, excellent thermal shock resistance, and low thermal conductivity, and is combined with the insulation layer 2 by on-site pouring;

[0024] The working layer 4 is a magnesium coating material, which is connected to the permanent layer 3 by spraying or painting, and has the advantages of convenient construction and easy bagging;

[0025] The oxygen barrier coating 5 is a corundum refractory material, which is connected to the working layer 4 by coating or spraying. Because the oxygen barrier coating has good sintering properties at high temperatures, a sintered layer will be formed on the coating surface. The surface of the sintered layer has a microporous structure, which not only prevents most of the O2 from penetrating and reduces the O2 content in the molten steel, but also can absorb inclusions in the molten steel and improve the quality of the molten steel. The utility model adds an oxygen barrier coating to the traditional tundish structure, which not only reduces the O2 content in the molten steel, but also the microporous structure generated by the sintered layer can absorb inclusions in the molten steel and improve the cleanliness of the molten steel.

[0026] In this embodiment, the thermal insulation layer 2 is composed of a nano-silicon dioxide plate with a thickness of 10 mm and a thermal conductivity of 0.02 W / (m·K).

[0027] In this embodiment, the permanent layer 3 is a silica sol castable made of corundum-mullite, with a thermal conductivity of 0.20 W / (m·K), a water-cooled thermal shock of more than 30 times, a high-temperature flexural strength of more than 3 Mpa at 1500°C, and a thickness of 100 mm.

[0028] In this embodiment, the working layer 4 is a magnesium coating material with a thickness of 80 mm.

[0029] In this embodiment, the oxygen barrier coating 5 is made of corundum material and has a thickness of 60 mm.

[0030] The tundish of the utility model can effectively reduce the O2 content in the molten steel, absorb the inclusions in the molten steel, and improve the cleanliness of the molten steel.

[0031] In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A tundish for ultrapure steel smelting with oxygen barrier function, characterized in that: The invention comprises, from the outside to the inside, a cladding (1), an insulation layer (2), a permanent layer (3), a working layer (4) and an oxygen barrier coating (5). The insulation layer (2) is laid on the inner surface of the cladding (1), the permanent layer (3) is poured on the surface of the insulation layer (2), the working layer (4) is then applied or sprayed on the surface of the permanent layer (3), and the oxygen barrier coating (5) is then adhered to the surface of the working layer (4) by applying or spraying.

2. The tundish for smelting ultrapure steel with oxygen barrier function according to claim 1, characterized in that: The thermal insulation layer (2) and the cladding (1) are bonded together by a high-temperature bonding agent.

3. The tundish for smelting ultrapure steel with oxygen barrier function according to claim 2, characterized in that: The thermal insulation layer (2) is a nano-silicon dioxide thermal insulation board, which has a laying thickness of 5 to 10 mm and a thermal conductivity coefficient of less than 0.02 W / (m·K).

4. The tundish for smelting ultrapure steel with oxygen barrier function according to claim 2, characterized in that: The permanent layer (3) is a silica sol-bonded castable material, with a casting thickness of about 80 to 160 mm, a thermal conductivity of less than 0.2 W / (m·K), a water-cooled thermal shock of more than 30 times, and a high-temperature flexural strength of more than 3 Mpa at 1500°C.

5. The tundish for smelting ultrapure steel with oxygen barrier function according to claim 4, characterized in that: The casting thickness of the permanent layer (3) is 80-140 mm.

6. The tundish for smelting ultrapure steel with oxygen barrier function according to claim 4, characterized in that: The material of the permanent layer (3) is corundum-mullite.

7. The tundish for smelting ultrapure steel with oxygen barrier function according to claim 2, characterized in that: The working layer (4) is a magnesium coating material, and its coating thickness is 60-100 mm.

8. The tundish for smelting ultrapure steel with oxygen barrier function according to claim 2, characterized in that: The oxygen barrier coating (5) is a corundum refractory material and has a coating thickness of 40 to 60 mm.

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