Ladle side argon blowing method and structure under low-iron-loss process

Abstract

The invention relates to a steel ladle side argon blowing method under a low-iron-loss process and a structure thereof. The method comprises the following steps: mounting side argon blowing air bricks in a range of a steel ladle slag line brick from the third layer to the fifth layer of the ladle bottom; the side-blowing air brick is connected with an original bottom-blowing air brick pipeline, and before converter tapping, a control valve of the bottom-blowing air brick and a control valve between the bottom-blowing air brick and the side-blowing air brick are opened; the argon blowing state is kept until the converter tapping process and the alloy scrap steel raw and auxiliary material adding process and the ladle hoisting process are carried out; after a steel ladle containing low-temperature molten steel is hoisted to an LF refining station through a crown block, bottom blowing and side argon blowing are immediately started, heating operation is carried out, and side argon blowing is stopped after the temperature of the molten steel rises. The auxiliary argon blowing air brick is mounted on the side wall of the steel ladle, so that the problem that molten steel heat transfer is affected by bad ladle bottom argon blowing can be solved, the problem that the service life of a slag line refractory material of the steel ladle is affected by bad heating temperature heat transfer of the upper layer of the steel ladle is reduced, meanwhile, production is smooth, the temperature of molten steel components is homogenized in time, and the phenomenon of production interruption caused by bad argon is solved.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, in particular to a ladle side blowing argon method under a low iron loss process and a structure thereof. Background Art

[0002] In order to reduce carbon emissions from the steelmaking process and meet the export requirements of steel products, the converter workshop adopts the method of increasing the proportion of scrap steel in converter steelmaking, such as adding scrap steel to the iron ladle, adding scrap steel to the converter, adding scrap steel to the ladle tapping, etc. As a result, the scrap steel ratio reaches 30% or even more than 40%, resulting in insufficient chemical heat and physical heat of the raw materials entering the furnace, and the converter tapping temperature drops; and during the tapping process, the temperature of the ladle drops further after adding scrap steel, and the bottom of the ladle is prone to cold steel, making it difficult to blow argon at the bottom of the ladle. The cold steel near the water inlet affects the self-opening of the ladle, and drainage is required for casting, affecting the quality of the molten steel. Therefore, low iron consumption and high scrap steel ratio production requires measures to be taken for the cold steel at the bottom of the ladle to meet production and quality requirements. Summary of the invention

[0003] The technical problem to be solved by the present invention is: to provide a method and structure for side blowing argon in a ladle under a low iron consumption process, which solves the problems that the cold steel at the bottom of the ladle affects the bottom blowing argon effect and the ladle water inlet does not open and drain automatically under the conditions of low iron consumption and large scrap steel ratio, as well as the possible argon gas blockage, the ladle return to the furnace, and the continuous casting interruption and production suspension due to the cold steel drainage at the bottom of the ladle.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a method for side blowing argon in a ladle under a low iron loss process, comprising the following steps: (1) Install side-blown argon permeable bricks within the 3rd to 5th layer of the slag line bricks at the bottom of the ladle; (2) The side-blowing argon permeable brick is connected to the original bottom-blowing permeable brick pipeline, and the valve is used to control the switch; (3) Before tapping the converter, open the control valve of the bottom-blowing air brick and the control valve between the bottom-blowing air brick and the side-blowing air brick; (4) Maintain the argon blowing state until the converter steel is tapped and alloy scrap raw and auxiliary materials are added and before the ladle is hoisted; (5) After the ladle containing low-temperature molten steel is lifted by the overhead crane to the LF refining station, the bottom blowing and side blowing of argon are immediately turned on to carry out the temperature-raising operation. After the temperature of the molten steel rises, the side blowing of argon is turned off.

[0005] Furthermore, in step (1) of the present invention, the material of the side-blown argon permeable brick is consistent with the material of the bottom-blown permeable brick at the bottom of the ladle, both of which are made of corundum. The installation position near the bottom of the ladle can facilitate the melting of cold steel at the bottom of the ladle and the floating of bubbles to drive the circulation and heat transfer of molten steel.

[0006] Furthermore, in step (5) of the present invention, the argon gas can be turned off when the low-temperature molten steel is transferred by the overhead crane to control the thickness of the cold steel at the bottom of the ladle to avoid the ladle being too thick and affecting the ladle pouring, thereby reducing the impact of ladle drainage on quality.

[0007] Furthermore, the argon blowing angle of the side-blown argon permeable brick of the present invention is opposite to the bottom-blown permeable brick, and the angle between the gas outlet direction of the side-blown argon permeable brick and the package wall is in the range of 30°~60°, which can solve the problem that the bottom permeable brick of the package is covered by cold steel and affects the bottom blowing effect.

[0008] At the same time, the present invention also provides a side-blowing argon structure for a ladle under a low iron loss process, including installing side-blowing argon permeable bricks within the 3rd to 5th layer range of the slag line bricks below the ladle from the bottom of the ladle; the side-blowing argon permeable bricks are connected to the original bottom-blowing permeable bricks through pipelines; and a control valve is arranged on the pipeline.

[0009] The beneficial effect of the present invention is that the defects existing in the background technology are solved. The present invention adopts auxiliary argon blowing air bricks installed on the side wall of the ladle, and the argon blowing angle of the side wall air bricks is opposite to the direction of the air bricks at the bottom of the ladle, which can solve the problem that the air bricks at the bottom of the ladle are covered by cold steel, affecting the poor argon blowing effect of the ladle bottom and affecting the heat transfer of the molten steel, and reduce the influence of poor heat transfer of the upper layer of the ladle on the life of the refractory material of the ladle slag line, while making the production go smoothly, and timely making the temperature of the molten steel composition uniform, solving the production interruption phenomenon caused by poor argon gas; the present invention is easy to install, environmentally friendly, and is similar to the principle of the top blowing argon gun, but saves the installation space of the top blowing argon gun, does not need to frequently replace the argon gun, and avoids the modification of the furnace cover and the dust hood due to the installation of the top blowing argon gun. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic diagram of a side-blown argon structure of the present invention; In the figure: 1. Bottom-blowing air-permeable brick; 2. Side-blowing argon air-permeable brick; 3. Pipeline; 4. Control valve. DETAILED DESCRIPTION

[0011] The present invention will now be described in further detail in conjunction with the accompanying drawings and preferred embodiments. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0012] like Figure 1 The illustrated structure of a side-blowing argon structure for a ladle under a low iron loss process includes installing side-blowing argon permeable bricks 3 within the range of the 3rd to 5th layers of the slag line bricks below the ladle from the bottom of the ladle; the side-blowing argon permeable bricks 3 are connected to the original bottom-blowing permeable bricks 1 through a pipeline 3; and a control valve 4 is provided on the pipeline.

[0013] The specific steps of the side blowing argon method are as follows: (1) Install side-blown argon permeable bricks within the 3rd to 5th layer of the ladle bottom slag line bricks. The material is the same as the ladle bottom permeable bricks, which are made of corundum. The gas outlet direction of the side-blown argon permeable bricks is in the angle range of 30° to 60° with the ladle wall; (2) The side-blowing argon permeable brick is connected to the original bottom-blowing permeable brick pipeline, and the valve is used to control the switch; (3) Open the control valves of bottom blowing air bricks and side blowing air bricks before tapping the converter; (4) The argon blowing state must be maintained during the process of tapping the converter and adding alloy scrap steel and other raw and auxiliary materials and before the ladle is hung; (5) After the ladle containing low-temperature molten steel is lifted by the overhead crane to the LF refining station, the bottom blowing and side blowing of argon are immediately turned on to carry out the temperature-raising operation. After the temperature of the molten steel rises, the side blowing of argon can be turned off.

[0014] The present invention is described in detail below with reference to embodiments, but the present invention is not limited to these embodiments.

[0015] Example 1 (1) Production of 45 steel: Raw material conditions: 105 tons of molten iron per tank, molten iron temperature 1350℃, molten iron Si: 0.25%, 8 tons of silicon steel sheets added to the iron ladle, and 37 tons of scrap steel added to the converter.

[0016] (2) Normal blowing, steel carbon content 0.06%, steel temperature 1592℃; (3) Start the bottom blowing and side blowing of argon gas in the ladle, open the ladle to tap steel from the furnace, and add 550 kg of carburizer, 1000 kg of silicon-manganese alloy, and 3000 kg of steel bar cut ends during the tapping process; (4) During the steel-making process, argon is blown normally to the ladle hanging position; (5) The molten steel was hoisted from the converter to the LF refining station, argon gas was turned on, and the temperature was measured at 1495°C. Sampling could not be performed at low temperatures; (6) After heating for 10 minutes, measure the temperature at 1520°C, take samples, and close the side-blowing argon gas pipeline; (7) After the molten steel is refined and qualified, the ladle is soft-blown normally until continuous casting, and the continuous casting is automatically opened without drainage; (8) After the ladle casting is completed, heat repair treatment is carried out and no cold steel is found near the water outlet at the bottom of the ladle.

[0017] Example 2 (1) To produce 20G steel, the raw material conditions are as follows: 115 tons of molten iron per tank, 1358°C molten iron temperature, 0.20% Si in molten iron, 6 tons of silicon steel sheets in the ladle, and 34 tons of scrap steel in the converter.

[0018] (2) Normal blowing, steel carbon content 0.07%, steel temperature 1586℃; (3) Start the bottom blowing and side blowing of argon gas in the ladle, open the ladle to tap steel from the furnace, and add 140 kg of carburizer, 500 kg of silicon-manganese alloy, and 3000 kg of steel bar cut heads during the tapping process; (4) During the steel-making process, argon is blown normally to the ladle hanging position; (5) The molten steel is hoisted from the converter to the LF refining station, argon gas is turned on, and the temperature is measured at 1515°C. Sampling is not possible at low temperatures; (6) After heating for 10 minutes, measure the temperature at 1538°C, take a sample, and close the side-blowing argon gas pipeline; (7) After the molten steel LF is refined to be qualified, the ladle is hoisted to RH vacuum refining, and the ladle is hoisted to continuous casting for normal soft blowing. The continuous casting is opened without drainage; (8) After the ladle casting is completed, heat repair treatment is carried out and no cold steel is found near the water outlet at the bottom of the ladle.

[0019] Comparative Example 1 (1) Production of 45 steel: Raw material conditions: 105 tons of molten iron per tank, molten iron temperature 1355℃, molten iron Si: 0.26%, 8 tons of silicon steel sheets added to the iron ladle, and 37 tons of scrap steel added to the converter.

[0020] (2) Normal blowing, steel carbon 0.05%, steel temperature 1598℃; (3) Start blowing argon from the bottom of the ladle, open the ladle to tap steel from the furnace, add 570 kg of carburizer, 1000 kg of silicon-manganese alloy, and 3000 kg of steel bar cuts during the tapping process; (4) During the steel-making process, argon is blown normally to the ladle hanging position; (5) The molten steel was hoisted from the converter to the LF refining station. Argon was turned on after the ladle was set. There was no argon gas. The temperature was measured at 1495°C and sampling could not be performed at low temperature. (6) After heating for 10 minutes, the temperature was measured at 1550°C, and there was still no argon; (7) The temperature was raised again for 10 minutes, and the temperature was measured at 1610°C. The argon effect was poor, and the slag line of the ladle showed signs of erosion. The ladle was forced to be turned over, and the molten steel was poured into another ladle; (8) When the ladle was heat-repaired without argon, it was found that the cold steel at the bottom of the ladle covered the air core and the water inlet.

[0021] Comparative Example 2 (1) Production of 45 steel, raw material conditions: 105 tons of molten iron per tank, molten iron temperature 1358℃, molten iron Si: 0.30%, 8 tons of silicon steel sheets added to the iron ladle, and 37 tons of scrap steel added to the converter.

[0022] (2) Normal blowing, steel carbon content 0.06%, steel temperature 1600℃; (3) Start blowing argon from the bottom of the ladle, open the ladle to tap steel from the furnace, and add 550 kg of carburizer, 1000 kg of silicon-manganese alloy, and 3000 kg of steel bar cut ends during the tapping process; (4) During the steel-making process, argon is blown normally to the ladle hanging position; (5) The molten steel was hoisted from the converter to the LF refining station. Argon was turned on after the ladle was set. There was no argon gas. The temperature was measured at 1501°C and sampling could not be done at low temperature. (6) After heating for 10 minutes, the temperature was measured at 1530°C, and the argon gas was too low; (7) Heat up again for 10 minutes, measure the temperature at 1545°C, the argon gas is normal, and take samples; (8) After the molten steel is refined and qualified, the ladle is normally soft-blown and then casted into continuous casting, and the continuous casting is not automatically opened for drainage operation; (9) After the ladle casting was completed, heat repair treatment was carried out and a large amount of cold steel was found near the water inlet at the bottom of the ladle.

[0023] Therefore, according to the above embodiments and comparative examples, it can be known that in the process of producing low-iron-loss, high-scrap steel and low-temperature molten steel by this method, the process requirements of uniform molten steel composition and temperature can be met through the refining of argon. The cold steel at the bottom of the ladle after casting is controlled, solving the problem of argon-free ladle inversion accidents and drainage difficulties caused by the cold steel at the bottom of the ladle.

[0024] The above description only describes the specific implementation mode of the present invention. Various examples do not limit the essential content of the present invention. After reading the description, ordinary technicians in the relevant technical field can modify or deform the specific implementation modes described above without departing from the essence and scope of the invention.

Claims

1. A method for side blowing argon from a ladle under a low iron loss process, characterized in that: The following steps are included: (1) Install side-blown argon permeable bricks within the 3rd to 5th layer of the slag line bricks at the bottom of the ladle; (2) The side-blowing argon permeable brick is connected to the original bottom-blowing permeable brick pipeline, and the valve is used to control the switch; (3) Before tapping the converter, open the control valve of the bottom-blowing air brick and the control valve between the bottom-blowing air brick and the side-blowing air brick; (4) Maintain the argon blowing state until the converter steel is tapped and alloy scrap raw and auxiliary materials are added and before the ladle is hoisted; (5) After the ladle containing low-temperature molten steel is lifted by the overhead crane to the LF refining station, the bottom blowing and side blowing of argon are immediately turned on to carry out the temperature-raising operation. After the temperature of the molten steel rises, the side blowing of argon is turned off.

2. A method and structure for side blowing argon from a ladle under a low iron loss process as claimed in claim 1, characterized in that: In the step (1), the material of the side-blowing argon permeable brick is the same as the material of the bottom-blowing permeable brick at the bottom of the ladle, both of which are made of corundum.

3. The method and structure for side blowing argon from a ladle under a low iron loss process according to claim 1, characterized in that: In the step (5), the argon gas can be turned off when the low-temperature molten steel is transferred by the overhead crane.

4. The method and structure for side blowing argon from a ladle under a low iron loss process according to claim 1, characterized in that: The angle between the gas outlet direction of the side-blown argon permeable brick and the wall is in the range of 30° to 60°, and the argon blowing angle of the side-blown argon permeable brick is opposite to the direction of the bottom-blown permeable brick.

5. A ladle side blowing argon structure under low iron loss process, characterized in that: The method comprises installing side-blowing argon permeable bricks within the range of the 3rd to 5th layers of the slag line bricks below the ladle from the bottom of the ladle; the side-blowing argon permeable bricks are connected with the original bottom-blowing permeable bricks through pipelines; a control valve is arranged on the pipeline; the argon blowing angle of the side-blowing argon permeable bricks faces the direction of the bottom-blowing permeable bricks, and the angle between the gas outlet direction of the side-blowing argon permeable bricks and the ladle wall is in the range of 30° to 60°.

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