A method for tapping steel from converter mouth

Abstract

The present invention provides a method for tapping steel from a converter mouth, which specifically comprises the following steps: (1) rocking the converter to a slag discharge position, stopping rocking when the slag surface is flush with the mouth, controlling the rocking speed to 15 to 30 seconds per revolution, controlling the rocking angle to 60 to 80 degrees, and releasing 1 / 2 to 2 / 3 of the slag; (2) rocking the converter to a zero position, adding lime thick slag through a high-level silo; (3) blowing argon gas from the bottom of the converter; (4) selecting nitrogen blowing as an oxygen lance blowing method to solidify the liquid slag in the furnace; (5) controlling the rocking of the converter, with a rocking angle of 40 to 60 degrees, and confirming whether the slag thickness at the furnace mouth of the converter on the iron transfer side is ≥200 mm; (6) moving a molten steel tank to the bottom of the converter; controlling the rocking speed to 15 to 30 seconds per revolution, stopping rocking when molten steel flows out, and starting to tap steel; during the tapping process, the molten steel flow rate is controlled to be 0.5 to 0.8 t / s. The technical solution of the present invention solves the problems of increased cost and potential safety hazards in the furnace mouth steel tapping method in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of iron and steel metallurgy, and in particular to a method for tapping steel from a converter furnace mouth. Background Art

[0002] As a container for smelting molten steel, the converter is responsible for smelting molten iron into molten steel. When the molten iron is smelted in the furnace through oxygen blowing and slag making, it is discharged into the molten steel tank through the converter tapping port and sent to the next process for smelting. After the molten steel is qualified, it is poured on the machine. As a key part of the converter, the converter tapping port has harsh working conditions and needs to withstand the erosion of high-temperature and highly oxidizing molten steel. Once the tapping port is improperly maintained, a steel leakage accident occurs at the tapping port during the tapping process, and the furnace needs to be stopped for treatment. At this time, the molten steel retained in the furnace cannot be discharged into the molten steel tank through the tapping port. The remaining molten steel and slag in the furnace can only be discharged into the slag tank through the furnace port, which not only increases the cost of the steel plant, but also easily causes other accidents and causes the accident to expand. Summary of the invention

[0003] In view of the technical problem of increased cost and potential safety hazard caused by the steel-tapping method of mixing molten steel and slag out of the furnace mouth when a fault occurs in the above-mentioned prior art, a method for steel-tapping from a converter furnace mouth is provided. In the event of an accident, when the converter steel-tapping mouth cannot be used any longer due to steel leakage or other reasons, the steel-tapping method provided by the present invention can quickly discharge the molten steel retained in the furnace into a molten steel tank, thereby reducing the accident handling time and reducing the losses of the steel plant.

[0004] The technical means adopted by the present invention are as follows:

[0005] A method for tapping steel from a converter mouth, comprising the following steps:

[0006] (1) Shake the converter to the slag discharge position. When the slag surface is flush with the furnace mouth, stop shaking the converter. Control the shaking speed to 15 to 30 seconds / revolution and the shaking angle to 60 to 80 degrees. Release 1 / 2 to 2 / 3 of the slag.

[0007] (2) Shake the converter to zero position and add lime thick slag through the high-level silo, with the addition amount of 8-12 kg / t;

[0008] (3) Blowing argon from the bottom of the converter;

[0009] (4) Nitrogen blowing is selected as the oxygen lance blowing method to solidify the liquid slag in the furnace;

[0010] (5) Control the converter to shake the furnace at an angle of 40 to 60 degrees, and confirm whether the thickness of the slag accumulation at the furnace mouth of the converter on the iron-adding side is ≥ 200 mm; if the thickness of the slag accumulation is ≥ 200 mm, proceed to step (6); if there is no slag accumulation or the thickness of the slag accumulation is less than 200 mm, use the gunning material to gun the furnace mouth until the slag accumulation thickness is 200 to 400 mm;

[0011] (6) Move the molten steel ladle to the bottom of the converter; control the furnace shaking speed to 15 to 30 seconds per revolution. When the molten steel flows out, stop shaking the furnace and start tapping. During the tapping process, the molten steel flow rate is controlled at 0.5 to 0.8 t / s.

[0012] Furthermore, in step (2), thick slag lime is added in batches, the amount added in each batch is controlled at 2 kg / t, and the interval time is controlled to be 30 to 50 seconds.

[0013] Furthermore, in step (3), the flow rate of argon gas at the bottom of the converter is controlled at 15 to 20 Nm 3 / min.

[0014] Furthermore, in step (3), the oxygen lance position is controlled at 1.8-2.8 m, and the nitrogen supply intensity is 2.6-3.50 Nm 3 / min·t, and the nitrogen blowing time is controlled at 30 to 90s to solidify the liquid slag in the converter.

[0015] Furthermore, in step (4), the MgO content of the gunning material used for gunning the furnace mouth is ≥70%, the particle size is ≤2 mm, and the sintering time of the gunning material is 10 to 15 minutes.

[0016] Furthermore, in step (5), the alloy to be alloyed is added to the molten steel tank in advance according to the requirements of the steel type to be smelted.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. In an accident state, when the converter tapping port cannot be used due to steel leakage or other reasons, the converter tapping method provided by the present invention can solve the problem in the accident state by tapping the converter tapping port, and provides favorable conditions for quickly handling the accident.

[0019] 2. The converter furnace mouth steel tapping method provided by the present invention separates molten steel from slag by taking thickening slag measures during the steel tapping process, and then performs steel tapping, thereby avoiding accidents of steel slag mixing and reducing accident loss costs.

[0020] Based on the above reasons, the present invention can be widely promoted in the field of iron and steel metallurgy. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only 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.

[0022] When the converter tapping port cannot continue to be used as the tapping port due to steel leakage or other reasons, the molten steel retained in the furnace can be tapped by a converter tapping method provided by the present invention, which specifically includes the following steps:

[0023] (1) Shake the converter to the slag discharge position. When the slag surface is flush with the furnace mouth, stop shaking the converter. Control the shaking speed to 15 to 30 seconds / revolution and the shaking angle to 60 to 80 degrees. Release 1 / 2 to 2 / 3 of the slag.

[0024] (2) Shake the converter to zero position and add lime thick slag through the high-level silo, with the addition amount of 8-12 kg / t;

[0025] (3) Blowing argon from the bottom of the converter;

[0026] (4) Nitrogen blowing is selected as the oxygen lance blowing method to solidify the liquid slag in the furnace;

[0027] (5) Control the converter to shake the furnace at an angle of 40 to 60 degrees, and confirm whether the thickness of the slag accumulation at the furnace mouth of the converter on the iron-adding side is ≥ 200 mm; if the thickness of the slag accumulation is ≥ 200 mm, proceed to step (6); if there is no slag accumulation or the thickness of the slag accumulation is less than 200 mm, use the gunning material to gun the furnace mouth until the slag accumulation thickness is 200 to 400 mm;

[0028] (6) Move the molten steel ladle to the bottom of the converter; control the furnace shaking speed to 15 to 30 seconds / revolution. When the molten steel flows out, stop shaking the furnace and start tapping. During the tapping process, control the tapping of steel in small flow, and control the molten steel flow rate to 0.5 to 0.8 t / s. When the molten steel has not been completely discharged but stops flowing out, control the furnace shaking angle to make the molten steel flow out again until the molten steel is completely discharged and the furnace is lifted;

[0029] (7) After steelmaking is completed, the molten steel tank is transported to the refining process, and after the temperature and composition meet the requirements, it is put into pouring.

[0030] Furthermore, in step (2), thick slag lime is added in batches, the amount added in each batch is controlled at 2 kg / t, and the interval time is controlled at 30 to 50 seconds.

[0031] Furthermore, in step (3), the flow rate of argon gas at the bottom of the converter is controlled at 15 to 20 Nm 3 / min.

[0032] Furthermore, in step (3), the oxygen lance position is controlled at 1.8-2.8 m, and the nitrogen supply intensity is 2.6-3.50 Nm 3 / min·t, and the nitrogen blowing time is controlled at 30 to 90s to solidify the liquid slag in the converter.

[0033] Furthermore, in step (4), the MgO content of the gunning material used for gunning the furnace mouth is ≥70%, the particle size is ≤2 mm, and the sintering time of the gunning material is 10 to 15 minutes.

[0034] Furthermore, in step (5), the alloy to be alloyed is added to the molten steel tank in advance according to the requirements of the steel type to be smelted.

[0035] Example 1

[0036] In this embodiment, steel was found to be scattered during the steel tapping process of a 260-ton converter in a certain factory, and the furnace was immediately lifted to check the steel tapping port. It was found that the outer edge of the steel tapping port had been eroded by molten steel and steel could not be tapped through the steel tapping port. The method for tapping steel from the converter port of the present invention was used, which specifically includes the following steps:

[0037] (1) Shake the converter to the slag discharge position, move the slag pot under the furnace mouth, stop shaking the furnace when the slag surface is flush with the furnace mouth, control the shaking speed to 15 to 30 seconds / revolution, and control the shaking angle to 60 to 80 degrees, and discharge 1 / 2 to 2 / 3 of the slag;

[0038] (2) The converter is shaken to zero position, and lime thick slag is added through the high-level silo. The thick slag lime is added in batches. The amount added in each batch is controlled at 0.5 tons, and the control interval time is 30 seconds. The total amount added is 2.6 tons;

[0039] (3) The converter bottom blowing gas, the converter bottom blowing gas flow rate is controlled at 15Nm 3 / min, the converter bottom blowing gas is argon;

[0040] (4) After adding lime, oxygen lance blowing is carried out. The oxygen lance position is controlled at 2.6m. Nitrogen is selected as the oxygen lance blowing method. The nitrogen supply intensity is 2.8Nm 3 / min·t, the nitrogen blowing time is controlled at 90s to solidify the liquid slag in the converter;

[0041] (5) Control the converter to shake the furnace at an angle of 60°, and confirm whether the thickness of the slag accumulation at the furnace mouth of the converter on the iron side is ≥200 mm. In this embodiment, the slag accumulation is small, and the furnace mouth needs to be repaired with a gunning material. The MgO content of the gunning material is ≥70%, and the particle size is ≤2 mm. The gunning standard is 200 mm higher than the cast iron furnace mouth. It can be used after sintering for 15 minutes;

[0042] (6) Place the molten steel ladle under the converter, and add the alloy to be alloyed into the molten steel ladle in advance according to the requirements of the steel type to be smelted; control the furnace shaking speed to 15 to 30 seconds / revolution, stop shaking the furnace when the molten steel flows out, and start tapping; during the tapping process, control the small flow of steel, and control the molten steel flow rate at 0.8 t / s. When the molten steel has not been completely discharged but stops flowing out, control the furnace shaking angle to make the molten steel flow out again, until the molten steel is completely discharged and the furnace is lifted;

[0043] (7) After steelmaking is completed, the molten steel tank is transported to the refining process, and after the temperature and composition meet the requirements, it is put into pouring.

[0044] 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 by 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 method for tapping steel from a converter mouth, characterized in that: It is used to make the molten steel retained in the furnace tap out through the converter outlet when the converter outlet cannot be used any more, and specifically comprises the following steps: (1) Shake the converter to the slag discharge position. When the slag surface is flush with the furnace mouth, stop shaking the converter. Control the shaking speed to 15 to 30 seconds / revolution and the shaking angle to 60 to 80 degrees. Release 1 / 2 to 2 / 3 of the slag. (2) Shake the converter to zero position and add lime thick slag through the high-level silo, with the addition amount of 8-12 kg / t; (3) Blowing argon from the bottom of the converter; (4) Nitrogen blowing is selected as the oxygen lance blowing method to solidify the liquid slag in the furnace; (5) Control the converter to shake the furnace at an angle of 40 to 60 degrees, and confirm whether the thickness of the slag accumulation at the furnace mouth of the converter on the iron-adding side is ≥ 200 mm; if the thickness of the slag accumulation is ≥ 200 mm, proceed to step (6); if there is no slag accumulation or the thickness of the slag accumulation is less than 200 mm, use the gunning material to gun the furnace mouth until the slag accumulation thickness is 200 to 400 mm; (6) Move the molten steel ladle to the bottom of the converter; control the furnace shaking speed to 15 to 30 seconds / revolution, stop shaking the furnace when the molten steel flows out, and start tapping; during the tapping process, the molten steel flow rate is controlled at 0.5 to 0.8 t / s; Add thick slag lime in batches, control the amount of each batch to less than 2kg / t, and control the interval time to 30 to 50 seconds.

2. The method for tapping steel from a converter mouth according to claim 1, characterized in that: In step (3), the argon flow rate of the converter bottom blowing is controlled at 15-20 Nm 3 / min.

3. The method for tapping steel from a converter mouth according to claim 1, characterized in that: In step (3), the oxygen lance position is controlled at 1.8-2.8m, and the nitrogen supply intensity is 2.6-3.50Nm 3 / min·t, and the nitrogen blowing time is controlled at 30 to 90s to solidify the liquid slag in the converter.

4. The method for tapping steel from a converter mouth according to claim 1, characterized in that: In step (4), the MgO content of the gunning material used for gunning the furnace mouth is ≥70%, the particle size is ≤2mm, and the sintering time of the gunning material is 10 to 15 minutes.

5. The method for tapping steel from a converter mouth according to claim 1, characterized in that: In step (5), the alloy to be alloyed is added to the molten steel tank in advance according to the requirements of the smelting steel grade.