阅读说明：本技术 一种降低终渣高度的转炉单渣留渣冶炼方法 (Converter single slag remaining smelting method capable of reducing final slag height ) 是由 刘忠建 高志滨 郭伟达 王忠刚 赵立峰 张海波 张丽 公斌 于 2019-09-30 设计创作，主要内容包括：本发明公开一种降低终渣高度的转炉单渣留渣冶炼方法,包括：1)铁水预处理工序；2)留渣工序；3)装入工序；4)吹炼工序：吹炼过程中分阶段控制；5)放钢。该降低终渣高度的转炉单渣留渣冶炼方法中,吹炼工序中分阶段控制,并实现对装入制度、供氧制度、造渣制度和终点进行控制,能够有效降低转炉终渣高度,从而减少转炉倒炉出钢次数,缩短冶炼周期,加快生产节奏。(The invention discloses a converter single slag remaining smelting method for reducing final slag height, which comprises the following steps: 1) a molten iron pretreatment process; 2) a slag remaining procedure; 3) a charging step; 4) a converting process: controlling in stages in the blowing process; 5) and (5) steel is placed. In the converter single-slag remaining slag smelting method for reducing the final slag height, the blowing process is controlled in stages, the charging system, the oxygen supply system, the slagging system and the end point are controlled, and the final slag height of the converter can be effectively reduced, so that the converter reversing tapping frequency is reduced, the smelting period is shortened, and the production rhythm is accelerated.)

1. A converter single slag remaining smelting method for reducing final slag height is characterized by comprising the following steps:

1) a molten iron pretreatment process;

2) a slag remaining procedure;

3) a charging step;

4) a converting process:

the blowing gun position is 1800 mm-1850 mm, the oxygen pressure is controlled at 0.80 MPa-0.85 MPa, and the blowing is 30Nm³—350Nm³When the lime is added, the lime accounts for 50% -60% of the total loading amount; 10kg/t-12kg/t dolomite, and the addition amount of the ore is 30% -40% of the total addition amount;

after the first batch is added, the oxygen pressure at the lance position is unchanged, and when foaming slag is generated in blowing for 4-6 min, the gradient at the lance position of the oxygen lance is reduced: namely, the lance position of the oxygen lance is reduced once every 20 to 30 seconds, and the lance position is reduced by 40 to 60mm each time; adding lime into the oxygen reducing lance by 4 to 5 batches at the same time of the oxygen reducing lance for the first 4 to 5 times to account for 10 to 13 percent of the total charging amount;

after the position of the oxygen reducing lance is 1450 mm-1500 mm, the oxygen pressure is controlled to be 0.88 MPa-0.92 MPa; blowing to 4000Nm at constant gun pressure³—4300Nm³The position of the gun is reduced to 1400 mm; adding ore according to 10-15% of the total addition of each batch during the constant gun and constant pressure period, and adding all ore 10min before blowing;

blowing to 4500Nm³—4600Nm³Reducing the position of the lance to 1350mm, and controlling the oxygen pressure to be 0.90-0.92 MPa;

converting to 4800Nm³—5000Nm³Reducing the gun position to 1000-1100 mm, and controlling the oxygen pressure to 0.92-0.95 MPa until the gun is lifted at the end point;

5) and (5) steel is placed.

2. The converter single slag remaining smelting method for reducing the final slag height according to claim 1, wherein the step 1) is as follows:

adjusting the scrap ratio and the molten iron temperature reduction condition according to the molten iron components and the design of the smelted steel seeds before the smelting, and controlling the adding amount of the ore in the smelting process of the converter within 27 kg/t.

3. The converter single slag remaining smelting method for reducing the final slag height according to claim 1, wherein the step 2) is as follows:

and determining the slag remaining amount in the furnace to be controlled between 40kg/t and 45kg/t, and after the last furnace finishes tapping, pouring out partial red slag from the front of the furnace according to the slag remaining amount, and then carrying out slag splashing protection.

4. The converter single slag remaining smelting method for reducing the final slag height according to claim 1, wherein the step 3) is as follows: charging scrap steel and molten iron.

5. The method for reducing the final slag height of the converter single-slag remaining slag according to claim 1, wherein the oxygen lance is lowered to 5m to 5.5m before the step 5), nitrogen is blown for 20 seconds to 30 seconds, and the nitrogen pressure is controlled to be 1.40MPa to 1.70 MPa.

6. The converter single slag remaining smelting method for reducing the final slag height according to claims 1 to 5, wherein the converter single slag remaining smelting method is used for smelting raw materials with molten iron and silicon of less than or equal to 0.50%.

Technical Field

The invention relates to the technical field of steel making, in particular to a converter single slag remaining smelting method capable of reducing the final slag height.

Background

With the development of steel technology, a slag remaining process becomes one of the development trends of converter steelmaking, the final slag height of a converter is difficult to control due to the large degree of foamed slag at the end point of a conventional converter single slag remaining smelting process, slag is easy to gush out from a furnace mouth in a steel discharging process, a series of production problems such as cable burning of a buggy ladle and the like are caused, partial slag has to be poured out of the converter forwards before steel discharging, then steel is discharged, and the smelting period is long and the production rhythm is slowed down.

In addition, the mode of firstly reversing the furnace and then placing steel also causes heat loss of molten steel, is easy to corrode a slag surface and is not beneficial to maintenance of a furnace body; the risk of steel splashing at the furnace mouth exists in the deslagging process, so that potential safety hazards exist; part of metal is easy to be brought out in the deslagging process, so that the consumption of steel materials is high.

In summary, how to reduce the final slag height of the converter for single slag remaining slag smelting of the converter, avoid the process of first reversing the converter and then discharging steel, shorten the smelting period and accelerate the production rhythm is a problem to be solved urgently by the technical staff in the field.

Disclosure of Invention

In view of the above, the invention provides a converter single slag remaining smelting method for reducing the final slag height, wherein the blowing process is controlled in stages, the charging system, the oxygen supply system, the slagging system and the end point are controlled, and the final slag height of the converter can be effectively reduced, so that the converter-reversing steel tapping frequency is reduced, the smelting period is shortened, and the production rhythm is accelerated.

In order to achieve the purpose, the invention provides the following technical scheme:

a converter single slag remaining smelting method for reducing final slag height is characterized by comprising the following steps:

1) a molten iron pretreatment process;

2) a slag remaining procedure;

3) a charging step;

4) a converting process:

the blowing gun position is 1800 mm-1850 mm, the oxygen pressure is controlled at 0.80 MPa-0.85 MPa, and the blowing is 30Nm³—350Nm³When the lime is added, the lime accounts for 50% -60% of the total loading amount; 10kg/t-12kg/t dolomite, and the addition amount of the ore is 30% -40% of the total addition amount;

after the first batch is added, the oxygen pressure at the lance position is unchanged, and when foaming slag is generated in blowing for 4-6 min, the gradient at the lance position of the oxygen lance is reduced: namely, the lance position of the oxygen lance is reduced once every 20 to 30 seconds, and the lance position is reduced by 40 to 60mm each time; adding lime into the oxygen reducing lance by 4 to 5 batches at the same time of the oxygen reducing lance for the first 4 to 5 times to account for 10 to 13 percent of the total charging amount;

after the position of the oxygen reducing lance is 1450 mm-1500 mm, the oxygen pressure is controlled to be 0.88 MPa-0.92 MPa; blowing to 4000Nm at constant gun pressure³—4300Nm³The position of the gun is reduced to 1400 mm; adding ore according to 10-15% of the total addition of each batch during the constant gun and constant pressure period, and adding all ore 10min before blowing;

blowing to 4500Nm³—4600Nm³Reducing the position of the lance to 1350mm, and controlling the oxygen pressure to be 0.90-0.92 MPa;

converting to 4800Nm³—5000Nm³Reducing the gun position to 1000-1100 mm, and controlling the oxygen pressure to 0.92-0.95 MPa until the gun is lifted at the end point;

5) and (5) steel is placed.

Preferably, in the above method for smelting single-slag remaining slag in a converter with a reduced final slag height, the step 1) is:

adjusting the scrap ratio and the molten iron temperature reduction condition according to the molten iron components and the design of the smelted steel seeds before the smelting, and controlling the adding amount of the ore in the smelting process of the converter within 27 kg/t.

Preferably, in the above method for smelting single-slag remaining slag in a converter with a reduced final slag height, the step 2) is:

and determining the slag remaining amount in the furnace to be controlled between 40kg/t and 45kg/t, and after the last furnace finishes tapping, pouring out partial red slag from the front of the furnace according to the slag remaining amount, and then carrying out slag splashing protection.

Preferably, in the above method for smelting single-slag remaining slag in a converter with a reduced final slag height, the step 3) is: charging scrap steel and molten iron.

Preferably, in the converter single-slag remaining slag smelting method for reducing the final slag height, the oxygen lance is reduced to 5 m-5.5 m before the step 5), nitrogen is blown for 20 seconds-30 seconds, and the nitrogen pressure is controlled to be 1.40MPa-1.70 MPa.

Preferably, in the converter single slag remaining smelting method for reducing the final slag height, the converter single slag remaining smelting method is used for smelting raw materials with molten iron silicon content of less than or equal to 0.50%.

The invention provides a converter single slag remaining smelting method for reducing final slag height, which comprises the following steps: 1) a molten iron pretreatment process; 2) a slag remaining procedure; 3) a charging step; 4) a converting process: the blowing gun position is 1800 mm-1850 mm, the oxygen pressure is controlled at 0.80 MPa-0.85 MPa, and the blowing is 30Nm³—350Nm³When the lime is added, the lime accounts for 50% -60% of the total loading amount; 10kg/t-12kg/t dolomite, and the addition amount of the ore is 30% -40% of the total addition amount; after the first batch is added, the oxygen pressure at the lance position is unchanged, and when foaming slag is generated in blowing for 4-6 min, the gradient at the lance position of the oxygen lance is reduced: namely, the lance position of the oxygen lance is reduced once every 20 to 30 seconds, and the lance position is reduced by 40 to 60mm each time; adding lime into the oxygen reducing lance by 4 to 5 batches at the same time of the oxygen reducing lance for the first 4 to 5 times to account for 10 to 13 percent of the total charging amount; after the position of the oxygen reducing lance is 1450 mm-1500 mm, the oxygen pressure is controlled to be 0.88 MPa-0.92 MPa; blowing to 4000Nm at constant gun pressure³—4300Nm³The position of the gun is reduced to 1400 mm; adding ore according to 10-15% of the total addition of each batch during the constant gun and constant pressure period, and adding all ore 10min before blowing; blowing to 4500Nm³-4600Nm³Reducing the position of the lance to 1350mm, and controlling the oxygen pressure to be 0.90-0.92 MPa; converting to 4800Nm³—5000Nm³Reducing the gun position to 1000-1100 mm, and controlling the oxygen pressure to 0.92-0.95 MPa until the gun is lifted at the end point; 5) and (5) steel is placed.

In the smelting method, the blowing process is controlled in stages, the charging system, the oxygen supply system, the slagging system and the end point are controlled, and the final slag height of the converter can be effectively reduced, so that the frequency of converter-reversing steel tapping is reduced, the smelting period is shortened, and the production rhythm is accelerated.

Detailed Description

The embodiment of the invention discloses a converter single slag remaining smelting method for reducing the final slag height, wherein the blowing process is controlled in a staged manner, the charging system, the oxygen supply system, the slagging system and the end point are controlled, and the final slag height of a converter can be effectively reduced, so that the converter reversing tapping frequency is reduced, the smelting period is shortened, and the production rhythm is accelerated.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention discloses a converter single slag remaining smelting method for reducing final slag height, which comprises the following steps:

1) a molten iron pretreatment process:

before the smelting, the scrap steel ratio and the molten iron cooling condition are designed and adjusted according to the components of molten iron and the smelted steel species (end point carbon and end point temperature), and the adding amount of ore in the smelting process of the converter is controlled within 27 kg/t;

2) a slag remaining procedure:

determining the amount of slag left in the furnace to be controlled between 40kg/t and 45kg/t, and pouring partial red slag out of the front of the furnace according to the amount of slag left after the last furnace finishes tapping and then carrying out slag splashing protection;

3) a loading process:

charging scrap steel and molten iron;

4) a converting process:

the blowing gun position is 1800 mm-1850 mm, the oxygen pressure is controlled at 0.80 MPa-0.85 MPa, and the blowing is 30Nm³—350Nm³When the lime is added, the lime accounts for 50% -60% of the total loading amount; 10kg/t-12kg/t dolomite, and the addition amount of the ore is 30% -40% of the total addition amount;

after the first batch is added, the oxygen pressure at the lance position is unchanged, and when foaming slag is generated in blowing for 4-6 min, the gradient at the lance position of the oxygen lance is reduced: namely, the lance position of the oxygen lance is reduced once every 20 to 30 seconds, and the lance position is reduced by 40 to 60mm each time; adding lime into the oxygen reducing lance by 4 to 5 batches at the same time of the oxygen reducing lance for the first 4 to 5 times to account for 10 to 13 percent of the total charging amount;

after the position of the oxygen reducing lance is 1450 mm-1500 mm, the oxygen pressure is controlled to be 0.88 MPa-0.92 MPa; blowing to 4000Nm at constant gun pressure³—4300Nm³The position of the gun is reduced to 1400 mm; during the constant-pressure period, the ore is added according to 10% -15% of the total addition of each batch, and the ore is blownAdding all ore in the first 10 min;

blowing to 4500Nm³-4600Nm³Reducing the position of the lance to 1350mm, and controlling the oxygen pressure to be 0.90-0.92 MPa;

converting to 4800Nm³—5000Nm³Reducing the gun position to 1000-1100 mm, and controlling the oxygen pressure to 0.92-0.95 MPa until the gun is lifted at the end point;

5) releasing steel;

before the step 5), the oxygen lance is lowered to 5 m-5.5 m, nitrogen is blown for 20 seconds-30 seconds, and the pressure of the nitrogen is controlled between 1.40MPa and 1.70 MPa.

The method for smelting the single slag and the residual slag of the upper converter is used for smelting raw materials with the silicon content of molten iron less than or equal to 0.50 percent. The slag tapping angle is verified by discharging steel once and shaking the furnace. The invention improves the non-reversing slag and deslagging tapping rate of 20 percent of the original single slag remaining process converter at the end point to more than 95 percent on the premise of not influencing the dephosphorization effect and other process requirements; the slag discharging angle at the end point of the steel discharging rocking furnace is improved to 85.3 degrees from 75.2 degrees on average in the conventional process. Compared with the prior art, the method has the following advantages and effects:

the smelting period of the converter is reduced by 2-4 min; the consumption of steel materials is reduced by 2 kg/t-3 kg/t; the tapping temperature loss is reduced by 8-10 ℃ compared with the conventional deslagging tapping process; the erosion of the slag surface of the furnace lining is reduced, the consumption of the repairing mass is reduced, and the consumption of the repairing mass is reduced by 0.083kg/t compared with the original consumption; the risk of slag pouring and steel splashing in front of the furnace is reduced, and the safe operation coefficient is improved; the phenomenon of slag discharging and phosphorus returning at the steel tapping hole caused by serious final slag foaming and incomplete furnace shaking is avoided.

The following description will be given of a converter single slag remaining slag smelting method by taking 8-furnace steel smelting in a 120t top-bottom combined blown converter as an example:

adjusting the scrap ratio and the molten iron temperature reduction condition according to the molten iron components and the smelted steel species (end point carbon and end point temperature) plan before the molten iron is fed into the converter, and controlling the adding amount of the ore in the smelting process of the converter within 27 kg/t; determining that the amount of slag left in the furnace is controlled between 40kg/t and 45 kg/t; the specific steel grade plan, the amount of slag left, the molten iron condition after cooling and the steel scrap condition are shown in table 1. After the last furnace finishes tapping, pouring out partial red slag from the front of the furnace according to the slag remaining amount, and then carrying out slag splashing furnace protection; after slag splashing is finished, filling scrap steel and molten iron; opening deviceThe lance position is 1800 mm-1850 mm (lance position refers to the distance between the lance nozzle and the liquid level of the molten pool), the open blowing oxygen pressure is controlled to be 0.82 Mpa-0.86 Mpa, and the blowing is 300Nm³—350Nm³When the lime is added, the lime accounts for 50% -60% of the total loading amount; 10kg/t-12kg/t dolomite, and the addition amount of the ore is 30% -40% of the total addition amount; the specific early gun position control parameters and the feeding condition are shown in table 2. After the first batch is added, the oxygen pressure at the lance position is unchanged, and when foaming slag is generated in blowing for 4-6 min, the gradient at the lance position of the oxygen lance is reduced: namely, the lance position of the oxygen lance is reduced once every 20 to 30 seconds, and the lance position is reduced by 40 to 60mm each time; adding lime into the oxygen reducing lance by 4 to 5 batches at the same time of the oxygen reducing lance for the first 4 to 5 times to account for 10 to 13 percent of the total charging amount; the concrete slag-forming time, the gun descending condition and the charging condition are shown in Table 3. After the position of the oxygen reducing lance is 1450 mm-1500 mm, the oxygen pressure is controlled to be 0.88 MPa-0.92 MPa; blowing to 4000Nm at constant gun pressure³—4200Nm³Reducing the gun position to 1390mm-1420mm, keeping the oxygen pressure unchanged; during the period, the ore is added according to 10% -15% of the total loading of each batch, and the whole ore is added before blowing for 10 min; the specific parameters are shown in Table 4. Blowing to 4500Nm³—4700Nm³When the oxygen pressure is controlled to be 0.90 MPa-0.92 MPa, the gun position is reduced to 1330mm-1360 mm; converting to 4800Nm³—5000Nm³Reducing the gun position to 1000-1100 mm, controlling the oxygen pressure to 0.92-0.95 MPa until the gun is lifted at the end point, and ensuring the gun pressing time to be more than 2.5 min; the specific parameters are shown in Table 5. Before steel is placed, the oxygen lance is lowered to 5 m-5.5 m, nitrogen is blown for 20 seconds-30 seconds, and the pressure of the nitrogen is controlled between 1.30MPa and 1.70 MPa; the specific nitrogen blowing parameters and the slag discharging angle of the rocking furnace are shown in Table 6.

TABLE 1 molten iron composition and scrap steel compounding ratio table of examples

TABLE 2 early stage gun position control parameter and charging condition statistics table

TABLE 3 statistical table of slag-off time, process lance dropping condition and lime addition condition

TABLE 4 statistical chart of gun position control and ore addition in process

TABLE 5 statistical chart of gun pressing condition and gun pressing time at end point