A converter high-iron steel ratio smelting control method

Abstract

The present invention belongs to the technical field of steelmaking processes, and relates to a control method for smelting high-iron steel ratio in a converter. The 80t converter of Chongqing Iron and Steel is used for smelting. By adjusting the slag splashing process technology, optimizing the feeding control during the blowing process, and optimizing the oxygen supply technology, the blowing process of the converter is made stable, and the splashing rate of the converter is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of steelmaking processes and relates to a method for controlling the smelting of converter steel with a high iron-to-steel ratio. Background Art

[0002] In the unstable market of the steel industry, the demand for scrap steel is gradually increasing, and the utilization coefficient of blast furnaces is continuously improving. For the converter to produce under different hot metal ratios, it is necessary to optimize the slag-making process of converter smelting, stabilize the process control of converter smelting, and prevent high iron-to-steel ratios from causing smelting splashes, thereby reducing the impact on the consumption of steel materials and auxiliary materials. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a method for controlling the smelting of converter steel with a high iron-to-steel ratio, optimizing the slag-making process of converter smelting, and controlling the splash rate of the converter ≤ 5%.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A method for controlling the smelting of converter steel with a high iron-to-steel ratio, comprising the following steps:

[0005] A. Charge hot metal and scrap steel into the converter for converter oxygen blowing smelting to obtain converter smelted steel liquid. The total charge is 75 - 85 tons of hot metal, and the iron-to-steel ratio is controlled at 1020 - 1060 kg / furnace;

[0006] B. Determine the slag retention amount of this furnace according to the hot metal conditions of this furnace, combined with the quality and amount of slag of the previous furnace end slag, and guide the slag pouring control;

[0007] C. Under the conditions of high-iron steel, during the blowing process control, adjust the addition of auxiliary materials according to the hot metal conditions to ensure a suitable slag system in the front, middle, and later stages of the furnace. Through the adjustment of the cooling coefficient K value, select the addition amount of composite ball coolant;

[0008] D. According to the situation of the previous furnace end slag, add magnesium balls and lime to the furnace for slag adjustment before slag splashing, and add coke breeze for deoxidation.

[0009] Optionally, in step B, the slag retention amount is controlled at 1 / 3.

[0010] Optionally, in step D, the nitrogen flow rate is set at 21000 M3 / h, and the slag splashing time is determined according to the slag formation situation to ensure the solidification of the slag in the furnace, and the target is controlled at 2.0 - 3.0 min.

[0011] Optionally, in the slag splashing process, the lance position is generally from high to low, and when the furnace bottom is high, the low-high-low mode is adopted.

[0012] Optionally, the effective slag splashing time ≥ 1.5 min.

[0013] Optionally, if the slag still has not solidified after the slag splashing time exceeds 3.0 min, 0.3 - 0.5 t of lime is used for thickening the slag, and then the hot metal charging operation is carried out.

[0014] Optionally, after the slag splashing is completed and before the scrap steel is added, composite balls or ore are added with an upper limit of ≤2.0 t. After the scrap steel is added, first tilt the furnace backward to 20 - 30 degrees, then tilt the furnace forward to 90 - 105 degrees, and then charge the hot metal to prevent the occurrence of cannon firing due to wet scrap steel.

[0015] The beneficial effects of the present invention are as follows: The present invention optimizes the slag-making process in converter steelmaking, stabilizes the control of the converter steelmaking process, and prevents splashing during steelmaking caused by a high hot metal to steel ratio, thereby reducing the impact on the consumption of iron and steel materials and auxiliary materials.

[0016] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent description, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following description. Detailed Embodiments

[0017] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0018] Specific Embodiment 1

[0019] A method for controlling converter steelmaking with a high hot metal to steel ratio is disclosed. The 80 t converter of Chongqing Iron and Steel is used for steelmaking. By adjusting the slag splashing process technology, optimizing the feeding control during the blowing process, and optimizing the oxygen supply technology, the blowing process in the converter is made stable, and the splashing rate in the converter is reduced. The specific steps are as follows:

[0020] 1. Molten iron and scrap steel are charged into the converter for converter oxygen blowing steelmaking to obtain converter steelmaking molten steel. The total charging amount is 83 ± 1 t, and the hot metal to steel ratio is controlled at 1020 - 1060 kg / furnace, with an average of 1045.35 kg / t.

[0021] 2. According to the molten iron conditions of the current furnace, combined with the quality of the final slag of the previous furnace (TFe content 16 - 21%) and the slag amount, the slag retention amount of this furnace is determined to guide the slag pouring control. The objective is: the slag retention amount is 1 / 3 (3 - 4 tons).

[0022] 3. Conditions for high-speed rail steel, control of the blowing process. According to the hot metal conditions, adjust the addition of auxiliary materials to ensure a suitable slag system in the furnace during the early, middle, and late stages. Adjust the addition amount of the composite ball coolant by adjusting the cooling coefficient K value. The specific reference is as follows in Tables 1 - 4:

[0023] Table 1 Reference addition amount of auxiliary materials during the blowing process

[0024]

[0025] Table 2 Calculation of coolant during the blowing process

[0026]

[0027]

[0028] Table 3 Timing of adding converter auxiliary materials during the process of smelting with all hot metal

[0029]

[0030] Table 4 Control situation of oxygen supply flow rate and lance position during the blowing process

[0031]

[0032] 4. According to the final slag situation of the previous furnace, add magnesium balls and lime to the furnace for slag adjustment before slag splashing. Add 0.1 - 0.15 tons of coke breeze for deoxidation. The addition amount of magnesium balls ≤ 0.4t / furnace;

[0033] Among them, the nitrogen flow rate is set at 21000M3 / h. In principle, the lance position during the slag splashing process is from high to low (adopt the low - high - low mode when the furnace bottom is high). The slag splashing time is determined according to the slag formation situation to ensure the solidification of the slag in the furnace. The target is controlled at 2.0 - 3.0min (the effective slag splashing time ≥ 1.5min). The specific content is referred to Table 1:

[0034] Table 1 Reference lance position during the slag splashing process

[0035]

[0036] If the slag in the furnace still does not solidify after the slag splashing time is greater than 3.0min, use 0.3 - 0.5t of lime for thickening the slag operation, and then carry out the hot metal charging operation; after the slag splashing is completed and before adding scrap steel, composite balls or ore can be added, with the upper limit ≤ 2.0 tons. After adding scrap steel, first tilt the furnace backward to 20 - 30 degrees, and then tilt the furnace forward to 90 - 105 degrees (if the scrap steel is wet, repeat the action 1 - 2 times), and then charge the hot metal to prevent the occurrence of explosion due to wet scrap steel.

[0037] Under the condition of the iron - steel ratio of 1020 - 1060kg / t in the present invention, the converter splashing rate is reduced from 7.75% to 4.34%, reducing the loss of iron and steel materials by 0.46kg / t.

[0038] 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 them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A method for controlling the smelting of high-iron steel ratio in a converter, characterized in that, It includes the following steps: A. Charge hot metal and scrap into a converter for converter oxygen blowing smelting to obtain converter-smelted molten steel. The total charge is 75 - 85 tons, and the weight ratio of hot metal to scrap is controlled at 1020 - 1060 kg / t per furnace; B. Determine the slag retention amount of this furnace according to the hot metal conditions of the current furnace, combined with the quality and amount of the final slag of the previous furnace, and guide the slag pouring control; the slag retention amount is controlled at 1 / 3; C. For high-titanium steel conditions, during the blowing process, adjust the addition of auxiliary materials according to the hot metal conditions to ensure a suitable slag system in the front, middle, and later stages of the furnace. Adjust the addition amount of composite pellet coolant by the cooling coefficient K value; D. According to the situation of the final slag of the previous furnace, add magnesium balls and lime to the furnace for slag adjustment before slag splashing, and add coke breeze for deoxidation; During the slag splashing process, the lance position is generally from high to low. When the furnace bottom is high, the low-high-low mode is adopted. If the slag in the furnace has not solidified after the slag splashing time is greater than 3.0 min, use 0.3 - 0.5 t of lime for thickening the slag operation, and then carry out the hot metal charging operation. After the slag splashing is completed and before adding scrap, add composite pellets or ore with an upper limit of 2.0 t. After adding scrap, first tilt the furnace backward to 20 - 30 degrees, then tilt the furnace forward to 90 - 105 degrees, and then charge hot metal to prevent the occurrence of explosion due to wet scrap.

2. The converter high-iron steel ratio smelting control method according to claim 1, characterized in that: In step D, the nitrogen flow rate is set at 21000 M 3 / h. The slag splashing time is determined according to the slagging condition to ensure the solidification of the slag in the furnace, and the target is controlled at 2.0 - 3.0 min.

3. A converter high-iron steel ratio smelting control method according to claim 1, characterized in that: The effective slag splashing time ≥ 1.5 min.

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