High-oxygen steel submersed nozzle and preparation and use methods thereof

Abstract

The invention discloses a high-oxygen steel submerged nozzle as well as a preparation method and a use method thereof. A nozzle body comprises the following components: 31%-35% of C, 49%-54% of Al2O3 and 13%-16% of SiO2; the composite layer comprises the following components in percentage by weight: 26%-30% of MgO and 70%-74% of Al2O3; a coating is attached to the surface of the composite layer and comprises the following components: more than or equal to 99% of MgO; and the slag line part is made of a zirconium carbon material. The preparation method of the water gap comprises the steps of burdening, mixing, forming and firing. The obtained submersed nozzle product is preheated and cast-on for use, continuous casting of 1600-2000 tons of molten steel can be achieved for steel with the oxygen activity controlled to be 1.5 * 10 <-4 >-3.0 * 10 <-4 >, the inner surface of the refractory material is good, the situation that small pieces of the refractory material enter the molten steel after being eroded to form inclusions is avoided, meanwhile, the situation that after the submersed nozzle is eroded, the structural size in the nozzle changes can be prevented, and the service life of the submersed nozzle is prolonged. And therefore, the quality of the continuous casting billet is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of steelmaking and continuous casting, and particularly relates to a high-oxygen steel immersion nozzle and a preparation and use method thereof. Background Art

[0002] The continuous casting process is mainly used to produce killed steel, which requires the oxygen content of the molten steel to be as low as possible to ensure that the product has high purity and no porosity defects. However, some steels require the molten steel to have a higher oxygen content. For example, the formation of type I MnS in free-cutting steel requires an oxygen content of 100 ppm, and enameled steel requires a large amount of oxide inclusions to improve anti-scale performance. Since high-oxygen steel releases a large amount of gas during the casting process, the molten steel boils, which is not conducive to stable production. To solve this problem, the existing technology uses a die casting method, but the production efficiency is low, and there are problems such as uneven structure and many impurities in the ingot; since the active oxygen content of high-oxygen steel exceeds 1.5×10 -4 When the refractory contains carbon, its surface decarburization will make the refractory structure porous and loose, and the oxidation of the refractory is very severe. Conventional refractory is severely corroded after casting 200 tons of molten steel, which seriously pollutes the molten steel. Refractory with magnesium-aluminum spinel inside, due to the high active oxygen content of molten steel, the organic resin binder in the refractory still has residues after high-temperature firing. After decarburization, the refractory structure becomes loose and cannot withstand long-term erosion by molten steel. Therefore, it is urgent to develop an immersion nozzle suitable for high-oxygen steel continuous casting and adopt appropriate processes for preparation and use.

[0003] The Chinese patent (application number 202220618868.8), named "Three major parts for continuous casting of high-oxygen enameled steel", is characterized in that the patent discloses three major parts for continuous casting of high-oxygen enameled steel, including a stopper rod, a tundish upper water inlet and an immersed long water inlet, the tundish upper water inlet is connected to the stopper rod and the immersed long water inlet, the immersed long water inlet includes an upper bowl mouth section, a connecting section, a slag line section and a water inlet section, the bottom of the upper bowl mouth section is sequentially provided with a connecting section, a slag line section and a water inlet section, the upper bowl mouth section is provided with a blowing assembly, a first channel is provided in the center of the upper bowl mouth section and the connecting section, a second channel is provided in the center of the slag line section and the water inlet section, the first channel is connected to the second channel and the diameter of the second channel is greater than the diameter of the first channel, this patent provides a three major parts for continuous casting of high-oxygen enameled steel with good thermal stability, good corrosion resistance, and improved corrosion resistance and oxidation resistance. A high-temperature anti-adhesive coating layer is applied to the inner wall of the water inlet channel. The high-temperature anti-adhesive coating layer is made of hollow alumina balls, and the thickness of the high-temperature anti-adhesive coating layer is 1 to 4 mm. The hollow alumina balls have a loose structure and react with Mn, Fe, and O in molten steel to generate (Mn, Fe)O·A12O3 particles. The MnO-FeO in the molten steel continues to react with the (Mn, Fe)O·A12O3 particles to generate a liquid phase on the refractory material. The liquid phase is easily washed away from the refractory material by the molten steel, causing refractory erosion, reducing the life of the refractory material, and affecting the quality of the steel.

[0004] In summary, when the existing technology produces high-oxygen steel, the nozzle is easily corroded under the high-oxygen condition of molten steel, which not only reduces the service life of the nozzle, but also the corroded small pieces of refractory material enter the molten steel and become inclusions. At the same time, after the immersion nozzle is corroded, the structural size inside the nozzle changes, causing the molten steel in the nozzle to flow sideways, and it is easy for the protective slag to be drawn into the continuous casting billet, thereby deteriorating the quality of the continuous casting billet. Therefore, it is urgently necessary to develop a high-oxygen steel immersion nozzle that is resistant to molten steel erosion when casting high-oxygen molten steel, thereby increasing the service life of the nozzle and ensuring the quality of the molten steel, as well as a preparation and use method thereof. Summary of the invention

[0005] In view of the problem that nozzles are easily corroded during the production of high-oxygen steel, the present invention provides a high-oxygen steel nozzle, which is resistant to erosion by high-oxygen molten steel and not prone to cracks during continuous casting of high-oxygen steel, thereby improving the nozzle life and ensuring the quality of molten steel, as well as a preparation and use method of the high-oxygen steel nozzle.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] One of the technical solutions of the present invention is to provide a high-oxygen steel immersion nozzle, comprising a nozzle body, a molten steel inlet and a molten steel outlet at both ends of the body, a composite layer tightly combined with the inner wall of the cavity inside the body, and a slag line in contact with the protective slag outside the body. The components of the nozzle body are calculated by weight percentage: C: 31% to 35%, Al2O3: 49% to 54%, SiO2: 13% to 16%; the components of the composite layer are calculated by weight percentage: MgO: 26% to 30%, Al2O3: 70% to 74%; a coating is attached to the surface of the composite layer, and the components of the coating are calculated by weight percentage: MgO ≥ 99%.

[0008] Furthermore, the components of the slag line are calculated by weight percentage: ZrO2: 80% to 85%, ZrB2: 9% to 12%, and C: 6% to 8%.

[0009] Furthermore, the molten steel inlet is cylindrical and the molten steel outlet is flat.

[0010] Furthermore, the thickness of the composite layer is 4 to 5 mm, and the thickness of the coating is 0.05 to 0.2 mm.

[0011] The second technical solution of the present invention is to provide a method for preparing a high oxygen steel immersion nozzle, comprising the following steps:

[0012] 1) Batching: The raw materials for preparing each part of the nozzle are weighed according to the percentage of the required ingredients. The raw material composition of the nozzle body is C: 31% ~ 35%, Al2O3: 49% ~ 54%, SiO2: 13% ~ 16%; the raw material composition of the composite layer is MgO: 26% ~ 30%, Al2O3: 70% ~ 74%;

[0013] 2) Mixing: The raw material of the nozzle body contains 3.0% to 3.5% of the phenolic resin binder, and the mixing time is 5 to 10 minutes; the raw material of the composite layer contains 3.5% to 4.0% of the phenolic resin binder, and the mixing time is 10 to 15 minutes; the raw material of the coating contains 16% to 20% of ethanol, and the mixing time is 3 to 5 minutes;

[0014] 3) Molding: A coating layer and a composite layer of thin refractory material are formed by using a mold. First, a coating with a thickness of 0.05 to 0.2 mm is sprayed on the mold forming the inner cavity. After the coating and the composite layer form a thin layer of refractory material, the mold forming the inner cavity and the thin layer of refractory material are put into the outer rubber sleeve together. The mixture of the nozzle body is first added, and then the mixture of the slag line is added. The mixture of the nozzle body is added again. The amount of material added is controlled according to the material required to fill the height of each section of the cavity. After isostatic pressing, it forms a whole to obtain an immersed nozzle;

[0015] 4) Firing: Firing the isostatically pressed immersion nozzle at a temperature of 1050-1200° C. to obtain an immersion nozzle product.

[0016] Furthermore, during batching, the composition of the slag line is ZrO2: 80% to 85%, ZrB2: 9% to 12%, C: 6% to 8%, the particle size of ZrO2 is 0.10 to 0.40 mm, the particle size of ZrB2 is 0.20 to 0.50 mm, and the particle size of C is 0.02 to 0.06 mm; during mixing, the phenolic resin binder accounts for 3% to 5% of the raw materials at the slag line, and the mixing time is 5 to 10 minutes.

[0017] Furthermore, during the batching, the particle size of C in the nozzle body raw material is 0.02-0.06 mm, the particle size of Al2O3 is 0.10-0.40 mm, and the particle size of SiO2 is 0.20-0.50 mm; the particle size of MgO in the composite layer raw material is 0.05-0.15 mm, and the particle size of Al2O3 is 0.10-0.20 mm.

[0018] Furthermore, during molding, the isostatic pressing pressure is controlled within the range of 150 to 300 MPa, and the holding time is controlled within the range of 30 to 60 s.

[0019] The third technical solution of the present invention is to provide a method for using a high-oxygen steel immersion nozzle, which specifically includes:

[0020] a) The high oxygen steel immersion nozzle is installed under the tundish for preheating, and the preheating time is 1.3 to 1.8 hours;

[0021] b) Using high oxygen steel immersion nozzle for continuous casting, the oxygen content is 1.5×10 -4 ~3.0×10 -4 The superheat of molten steel during casting is 30±5℃, the thickness of continuous casting billet is 150-180mm, the width of continuous casting billet is 1800-2200mm, and the billet drawing speed is 1.0-1.3m / min, realizing continuous casting of 1600-2000 tons of high oxygen steel molten steel.

[0022] Furthermore, the preheating time includes: a1) from room temperature to 700-750°C, the preheating time is controlled within 15-30 minutes; a2) from 700-750°C to 1180-1200°C, the preheating time is controlled within 63-78 minutes.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention controls the oxygen activity at 1.5×10 -4 ~3.0×10 -4The steel type can realize the continuous casting of 1600-2000 tons of high-oxygen steel liquid steel, and the inner surface of the refractory is good, and small pieces of refractory materials will not be corroded and enter the molten steel to become inclusions. A12O3 in conventional refractory materials reacts with Mn, Fe, and O in the molten steel to form (Mn, Fe)O·A12O3 particles. MnO-FeO in the molten steel continues to react with the (Mn, Fe)O·A12O3 particles, which will generate a liquid phase on the refractory material. The liquid phase is easily washed away from the refractory material by the molten steel, causing erosion of the refractory material, reducing the life of the refractory material, and affecting the quality of the steel. The present invention forms MgO and MgO·A12O3 in the refractory coating and the composite layer, which can avoid the reaction of FeO and MnO in the molten steel with the refractory material, prevent the immersion nozzle from being corroded, and prevent the structural size of the nozzle from changing, causing nozzle deviation and protective slag involvement, thereby ensuring the quality of the continuous casting billet.

[0025] 2. The present invention realizes continuous casting of 1600-2000 tons of high-oxygen steel liquid, reduces the cutting head and tail of the continuous casting billet and the amount of residual steel in the tundish, improves the molten steel recovery rate, reduces the consumption of steel materials, saves production costs, and improves the competitiveness of enterprises.

[0026] 3. The high oxygen steel immersion nozzle used in the present invention and its preparation and use method have simple structure, are easy to operate, require small investment, and do not require additional equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 : Left view of the submerged nozzle;

[0028] Figure 2 : Front view of the submerged nozzle.

[0029] In the figure: 1. Molten steel inlet, 2. Coating, 3. Composite layer, 4. Nozzle body, 5. Slag line, 6. Molten steel outlet. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. 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.

[0031] To further describe the present invention, the present invention is described in more detail below in conjunction with embodiments:

[0032] 1. High oxygen steel immersion nozzle

[0033] like Figure 1 ,2 As shown, the high oxygen steel immersion nozzle includes a molten steel inlet 1, a coating 2, a composite layer 3, a nozzle body 4, a slag line 5, and a molten steel outlet 6. The nozzle body 4 has a composition of C: 31% to 35%, Al2O3: 49% to 54%, and SiO2: 13% to 16%. The thickness of the composite layer 3 is 4 to 5 mm, and its composition is MgO: 26% to 30%, Al2O3: 70% to 74%, and the composite layer 3 is tightly combined with the nozzle body 4. The coating 2 is attached to the composite layer 3, and the composition of the coating 2 is MgO content ≥ 99%, and the thickness is 0.05 to 0.2 mm. The molten steel enters the immersion nozzle from the molten steel inlet 1, and the refractory material, the coating and the composite layer are composed of MgO and MgO·A12O3, which can inhibit the formation of (Mn, Fe)O·A12O3 particles on the surface of the refractory composite layer, thereby preventing the surface of the refractory composite layer from being corroded. The composition of the slag line is ZrO2: 80% to 85%, ZrB2: 9% to 12%, C: 6% to 8%. The molten steel enters the continuous casting crystallizer through the molten steel outlet 6. When casting at the immersion nozzle, the slag line part in contact with the protective slag is made of zirconium carbon material to improve the corrosion resistance of the immersion nozzle. The molten steel inlet 1 is cylindrical, and the molten steel outlet 6 is flat, which is suitable for casting thin slabs. The relevant parameters of each part of the nozzle of the embodiment and the comparative example are shown in Table 1.

[0034] Table 1 Parameters of various parts of the nozzle

[0035]

[0036] As can be seen from Table 1, the comparative example has no coating, and the composition of the composite layer is C: 4% to 6%, Al2O3: 22% to 26%, SiO2: 68% to 74%. The C and SiO2 in the composite layer react with FeO and MnO under the action of high-oxygen steel molten steel, making the composite layer surface of the refractory material rough, and FeO and MnO react with A12O3 in the refractory material to generate (Mn, Fe)O·A12O3 particles, and FeO and MnO further react with (Mn, Fe)O·A12O3 to form a liquid phase, which is easily washed away from the refractory material by molten steel, causing erosion of the refractory material, reducing the life of the refractory material, and affecting the quality of the steel. The present invention forms MgO and MgO·A12O3 in the refractory coating and the composite layer, avoids the reaction of FeO and MnO with the refractory material, prevents the inner surface of the refractory material from being corroded, and solves the problem of small amount of molten steel when continuously casting high-oxygen steel.

[0037] 2. Preparation of high oxygen steel immersion nozzle

[0038] The preparation of the high oxygen steel immersion nozzle includes the following steps:

[0039] 1) Batching: The raw materials for preparing each part of the nozzle are weighed according to the percentage of the required ingredients. The composition of the composite layer 3 is MgO: 26% ~ 30%, Al2O3: 70% ~ 74%, the particle size of MgO is 0.05 ~ 0.15mm, the particle size of Al2O3 is 0.10 ~ 0.20mm, the composition of the nozzle body 4 is C: 31% ~ 35%, Al2O3: 49% ~ 54%, SiO2: 13% ~ 16%, the particle size of C ... particle size of C is 0.05 ~ 0.15mm, the particle size of Al2O3 is 0.10 ~ 0.20mm, the particle size of C is 0.05 ~ 0.15mm, the particle size of Al2O3 is 0.10 ~ 0.20mm, the particle size of C is 0.05 ~ 0.15mm, the particle size of Al2O3 is 0.10 ~ 0.20mm, the particle size of C is 0.05 ~ 0.15 The particle size of Al2O3 is 0.10-0.40mm, the particle size of SiO2 is 0.20-0.50mm, and the composition of the slag line is ZrO2: 80%-85%, ZrB2: 9%-12%, C: 6%-8%. The particle size of ZrO2 is 0.10-0.40mm, the particle size of ZrB2 is 0.20-0.50mm, and the particle size of C is 0.02-0.06mm.

[0040] 2) Mixing: the ethanol content in the coating is 16% to 20%, and the mixing time is 3 to 5 minutes. When mixing the raw materials for the composite layer 3, the phenolic resin binder content is 3.5% to 4.0%, and the mixing time is 10 to 15 minutes. When mixing the raw materials for the nozzle body 4, the phenolic resin binder content is 3.0% to 3.5%, and the mixing time is 5 to 10 minutes. When mixing the raw materials for the slag line 5, the phenolic resin binder content is 3% to 5%, and the mixing time is 5 to 10 minutes.

[0041] 3) Forming: A thin layer of refractory material is formed by using a steel mold to form a coating layer and a composite layer. First, a coating 2 with a thickness of 0.05 to 0.2 mm is sprayed on the mold forming the inner cavity. The particle size of MgO in the coating 2 is 0.01 to 0.02 mm, and ethanol accounts for 16% to 20%. Ethanol evaporates and is removed quickly in the coating without any side effects on the coating. After obtaining the thin layer of refractory material, the mold forming the inner cavity and the thin layer of refractory material are loaded into the outer rubber sleeve together, and the mixture of the nozzle body 4 is added first, and then the mixture of the slag line is added, and the mixture of the nozzle body 4 is added again. The amount of material added is controlled according to the material required to fill each section of the cavity height. After isostatic pressing, it forms a whole. The isostatic pressing pressure is controlled at 150 to 300 MPa, and the pressure holding time is 30 to 60 seconds. An immersed nozzle is obtained.

[0042] 4) Firing: The static isostatically pressed immersion nozzle is fired at a temperature of 1050-1200° C. to obtain an immersion nozzle product. The relevant parameters of various parts of the nozzles of the embodiment and the comparative example are shown in Table 2.

[0043] Table 2 Nozzle process parameters

[0044]

[0045]

[0046] The particle size of the comparative composite layer C is 0.02-0.06 mm, the particle size of Al2O3 is 0.10-0.40 mm, the particle size of SiO2 is 0.20-0.50 mm, and the particle size of MgO is 0.05-0.15 mm. When the raw materials of the composite layer are mixed, the phenolic resin binder accounts for 3.5%-4.0%, and the mixing time is 10-15 min. It can be seen from Table 2 that there is not much difference in the preparation process.

[0047] 3. Use of high oxygen steel immersion nozzle

[0048] a) The high oxygen steel immersion nozzle is installed under the tundish for preheating, and the preheating time is 1.3 to 1.8 hours. Among them, a1) from room temperature to 700 to 750 ° C, the preheating time is controlled at 15 to 30 minutes; a2) from 700 to 750 ° C to 1180 to 1200 ° C, the preheating time is controlled at 63 to 78 minutes.

[0049] The oxygen content of continuous casting using high oxygen steel immersion nozzle is 1.5×10 -4 ~3.0×10 -4 The superheat of the molten steel during casting is 30±5℃, the thickness of the continuous casting billet is 150-180mm, the width of the continuous casting billet is 1800-2200mm, and the billet drawing speed is 1.0-1.3m / min, realizing the continuous casting of 1600-2000 tons of high oxygen steel. After casting a certain weight of molten steel, the nozzle is removed, and the changes in the inner surface of the immersion nozzle are observed after cooling. The results are shown in Table 3.

[0050] Table 3 Water nozzle usage and effects

[0051]

[0052]

[0053] In summary, it can be seen from Table 3 that the three-layer composite immersion nozzle is used for casting, and the active oxygen content is controlled at 1.5×10 -4 ~3.0×10 -4 When the immersion nozzle of the present invention is used, continuous casting of 1600-2000 tons of molten high-oxygen steel is realized, which significantly increases the continuous casting weight of molten steel. It does not cause the nozzle refractory to be corroded and enter the steel to form foreign inclusions. At the same time, it does not cause the internal shape to change due to the corrosion of the nozzle refractory, and does not cause the phenomenon of molten steel flowing sideways and causing slag rolling. It effectively ensures the quality of the continuously cast billet and is beneficial to reducing production costs.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high oxygen steel immersion nozzle, comprising a nozzle body (4), a molten steel inlet (1) and a molten steel outlet (6) at both ends of the body, a composite layer (3) tightly bonded to the inner wall of the cavity inside the body, and a slag line (5) outside the body in contact with the protective slag, characterized in that: The components of the nozzle body (4) are calculated by weight percentage: C: 31% to 35%, Al2O3: 49% to 54%, SiO2: 13% to 16%; the components of the composite layer (3) are calculated by weight percentage: MgO: 26% to 30%, Al2O3: 70% to 74%; a coating (2) is attached to the surface of the composite layer (3), and the components of the coating (2) are calculated by weight percentage: MgO ≥ 99%.

2. The high oxygen steel immersion nozzle according to claim 1, characterized in that: The components of the slag line (5) are calculated by weight percentage: ZrO2: 80% to 85%, ZrB2: 9% to 12%, and C: 6% to 8%.

3. The high oxygen steel immersion nozzle according to claim 1, characterized in that: The molten steel inlet (1) is cylindrical, and the molten steel outlet (6) is flat.

4. The high oxygen steel immersion nozzle according to claim 1 or 2, characterized in that: The thickness of the composite layer (3) is 4 to 5 mm, and the thickness of the coating (2) is 0.05 to 0.2 mm.

5. A method for preparing a high oxygen steel immersion nozzle according to any one of claims 1 to 4, characterized in that: 1) Batching: The raw materials for preparing each part of the nozzle are weighed according to the percentage of the required ingredients. The raw material composition of the nozzle body is C: 31% ~ 35%, Al2O3: 49% ~ 54%, SiO2: 13% ~ 16%; the raw material composition of the composite layer is MgO: 26% ~ 30%, Al2O3: 70% ~ 74%; 2) Mixing: The raw material of the nozzle body contains 3.0% to 3.5% of the phenolic resin binder, and the mixing time is 5 to 10 minutes; the raw material of the composite layer contains 3.5% to 4.0% of the phenolic resin binder, and the mixing time is 10 to 15 minutes; the raw material of the coating contains 16% to 20% of ethanol, and the mixing time is 3 to 5 minutes; 3) Forming: A coating layer and a composite layer of a thin layer of refractory material are formed by using a mold. First, a coating (2) with a thickness of 0.05 to 0.2 mm is sprayed on the mold forming the inner cavity. After the coating (2) and the composite layer form a thin layer of refractory material, the mold forming the inner cavity and the thin layer of refractory material are placed in an outer rubber sleeve. The mixture of the nozzle body (4) is first added, and then the mixture of the slag line is added. The mixture of the nozzle body (4) is added again. The amount of material added is controlled according to the material required to fill the height of each section of the cavity. After isostatic pressing, it is formed into a whole to obtain an immersed nozzle; 4) Firing: Firing the isostatically pressed immersion nozzle at a temperature of 1050-1200° C. to obtain an immersion nozzle product.

6. The method for preparing a high oxygen steel immersion nozzle according to claim 5, characterized in that: During batching, the composition of the slag line is ZrO2: 80%-85%, ZrB2: 9%-12%, C: 6%-8%, the particle size of ZrO2 is 0.10-0.40mm, the particle size of ZrB2 is 0.20-0.50mm, and the particle size of C is 0.02-0.06mm; during mixing, the phenolic resin binder accounts for 3%-5% of the raw materials at the slag line, and the mixing time is 5-10min.

7. The method for preparing a high oxygen steel immersion nozzle according to claim 5, characterized in that: When mixing the ingredients, the particle size of C in the nozzle body raw material is 0.02-0.06mm, the particle size of Al2O3 is 0.10-0.40mm, and the particle size of SiO2 is 0.20-0.50mm; the particle size of MgO in the composite layer raw material is 0.05-0.15mm, and the particle size of Al2O3 is 0.10-0.20mm.

8. The method for preparing a high oxygen steel immersion nozzle according to claim 5, characterized in that: During molding, the isostatic pressing pressure is controlled at 150-300 MPa, and the holding time is controlled at 30-60 s.

9. A method for using the high oxygen steel immersion nozzle according to any one of claims 1 to 3, characterized in that: a) The high oxygen steel immersion nozzle is installed under the tundish for preheating, and the preheating time is 1.3 to 1.8 hours; b) Using high oxygen steel immersion nozzle for continuous casting, the oxygen content is 1.5×10 -4 ~3.0×10 -4 The superheat of molten steel during casting is 30±5℃, the thickness of continuous casting billet is 150-180mm, the width of continuous casting billet is 1800-2200mm, the billet drawing speed is 1.0-1.3m / min, and the continuous casting of 1600-2000 tons of high oxygen steel molten steel is achieved.

10. The method for using the high oxygen steel immersion nozzle according to claim 9, characterized in that: The preheating time includes: a1) from room temperature to 700-750°C, the preheating time is controlled within 15-30 minutes; a2) from 700-750°C to 1180-1200°C, the preheating time is controlled within 63-78 minutes.

Images