阅读说明：本技术 一种转炉冶炼高磷钢的方法 (Method for smelting high-phosphorus steel by converter ) 是由 赵科 邓长付 曾令宇 刘志明 何智荣 覃小峰 刘志龙 余衍丰 余大华 李宁 佟迎 于 2018-12-10 设计创作，主要内容包括：本发明涉及一种转炉冶炼高磷钢的方法,包括如下步骤：第一步：转炉开吹5min内一次性加完活性石灰和轻烧白云石,终渣碱度控制在2.0~2.5,冶炼过程氧压0.85~1.00Mpa；吹炼枪位比正常脱磷炉次低100~200mm,吹炼过程氧枪采用高—低—低枪位,控制终点碳温命中；在吹氧80%~85%时副枪测TSC的熔池温度控制在1610℃～1640℃；吹氧结束前100秒内禁止加冷料；第二步：转炉终点控C：0.04~0.09%,出钢温度控制在1645℃~1685℃,终点控P：0.040~0.070%；第三步：出完钢后倒部分炉渣,加轻烧白云石溅渣护炉,根据溅渣后渣量情况,决定是否需要倒渣,留渣量控制在3~5t,进行下炉含磷钢冶炼。本发明既能降低渣料和合金消耗,又能确保转炉连续平稳冶炼。(The invention relates to a method for smelting high-phosphorus steel by a converter, which comprises the following steps of firstly, adding active lime and lightly-burned dolomite at one time within 5min of converter blowing, controlling the alkalinity of final slag to be 2.0 ~.5, controlling the oxygen pressure in the smelting process to be 0.85 ~.00 Mpa, controlling the temperature of a molten pool measured by an auxiliary gun to be 1610-1640 ℃ when the oxygen lance is in a high-low lance position in the blowing process and controlling the end point carbon temperature to hit when the oxygen lance is 80% and 5985%, prohibiting cold charge addition within 100 seconds before the oxygen blowing is finished, secondly, controlling the end point C to be 0.04 ~.09%, controlling the tapping temperature to be 1645 ℃ and 3875 ℃ and controlling the end point P to be 0. ~.070 when the oxygen lance is 80%, and thirdly, pouring part of slag after steel is discharged, adding the lightly-burned dolomite into the converter, determining whether slag pouring is needed according to the slag protection condition after slag splashing, controlling the slag pouring amount to be in a stable manner, and ensuring that the slag consumption of the converter can be reduced by ~ and the invention can be continuously smelted.)

1. A method for smelting high-phosphorus steel in a converter comprises the following steps:

firstly, active lime and light burned dolomite are added once within 5min of converter blowing, the adding amount of the active lime is 2 ~ kg/ton steel, the adding amount of the light burned dolomite is 7 ~ kg/ton steel, the alkalinity of final slag is controlled to be 2.0 ~.5, the oxygen pressure in the smelting process is 0.85 ~.00 Mpa, an oxygen lance adopts a high-low lance position in the blowing process, the high lance position is firstly opened for oxygen ignition in the early stage of the blowing process, then the low lance position is heated to melt slag and waste steel, the lance position is properly improved in the middle stage of the blowing process to prevent drying, the carbon is pulled at the low lance position in the later stage of the blowing process, the temperature of the end point carbon is controlled, the blowing lance position is 100 ~ mm lower than that of a normal dephosphorization furnace, the lance position in the process is controlled according to the principle that the slag is not foamed, does not return to dry, is not sprayed, the slag is quickly heated, the slag is uniformly, the temperature is controlled to be within 1610 ℃ to 0.90 ℃ in the later stage of the blowing oxygen pressure, the oxygen pressure is controlled to be 0.90.00 second, the oxygen addition is forbidden to be completed before the cold oxygen blowing process is completed in at least 5970 seconds;

secondly, controlling the C at the end point of the converter to be 0.04 ~ 0.09.09%, controlling the tapping temperature to be 1645 ℃, ~ 1685 ℃ and controlling the P at the end point to be 0.040 ~ 0.070.070%, and adding ferrophosphorus for fine adjustment if the end point phosphorus does not reach the target component of the steel grade;

thirdly, pouring part of slag after steel is discharged, adding light-burned dolomite for slag splashing and protecting the furnace, determining whether slag needs to be poured according to the slag amount condition after slag splashing, controlling the slag amount to be 3 ~ 5t, and smelting the phosphorus-containing steel in the next furnace.

2. The method for smelting high-phosphorus steel in the converter according to claim 1, wherein the lance position of the oxygen lance in the blowing process of the first step is in the blowing early stage: starting a lower gun to blow oxygen for 80 seconds at 1800mm, stopping the lower gun to blow oxygen for 99 seconds at 1650mm, and continuing to blow oxygen for 160 seconds at 1450 mm; in the middle stage of converting: lifting the lance to 1500mm and blowing oxygen for 380 seconds; and in the later stage of converting: the oxygen blowing is carried out for 120 seconds when the oxygen is blown to 1350mm, and the oxygen blowing is carried out for 78 seconds when the oxygen is blown to 1200 mm.

3. The method for smelting high-phosphorus steel in the converter according to claim 1, wherein the lance position of the oxygen lance in the blowing process of the first step is in the blowing early stage: starting a lower gun to blow oxygen for 90 seconds at 1800mm, then discharging the lower gun to blow oxygen for 89 seconds at 1650mm, and then continuing to discharge the lower gun to blow oxygen for 170 seconds at 1500 mm; in the middle stage of converting: lifting the lance to 1550mm and blowing oxygen for 370 seconds; and in the later stage of converting: the oxygen blowing is carried out for 90 seconds when the lance is lowered to 1400mm, and the lance is lifted after the lance is lowered to 1250mm, and the carbon is pulled and the oxygen is blown for 88 seconds.

4. The method for smelting high-phosphorus steel in the converter according to claim 1, wherein the lance position of the oxygen lance in the blowing process of the first step is in the blowing early stage: starting a lower gun to blow oxygen for 150 seconds at 1800mm, then discharging the lower gun to blow oxygen for 80 seconds at 1650mm, and continuing to discharge the lower gun to blow oxygen for 140 seconds at 1480 mm; in the middle stage of converting: lifting the lance to 1550mm and blowing oxygen for 360 seconds; and in the later stage of converting: the oxygen blowing is carried out for 100 seconds when the lance is lowered to 1400mm, and the lance is lifted after the lance is lowered to 1250mm, and the carbon is pulled and the oxygen is blown for 82 seconds.

5. A method for smelting high-phosphorus steel in a converter according to any one of claims 1 to 4, wherein if the upper furnace is used for smelting non-phosphorus-containing steel, the method comprises the following steps of adjusting the proportion of scrap steel according to the temperature of molten iron components (Si: 0.20 ~ 0.60.60%, P: 0.090 ~ 0.120.120% and 1270 ~ 1360%) during the lower furnace smelting, controlling the temperature of a cold charge in the blowing process to be within 1t, controlling the temperature of a cold charge to be less than that of the cold charge to be beneficial to phosphorus preservation, controlling the final phosphorus of the steel grade to be 0.040 ~ 0.070.070% and the dephosphorization rate to be 40 ~ 65%, splashing slag after the non-phosphorus-containing steel is discharged, determining whether slag pouring is needed or not according to the slag amount after splashing, controlling the slag amount to be 3 ~ 5t, and preparing for smelting the phosphorus-containing steel in the next furnace.

Technical Field

The invention relates to the technical field of converter steelmaking, in particular to a method for smelting high-phosphorus steel by a converter.

Background

The phosphorus content of the free-cutting steel such as 1215CW, 1215YG, 1214Bi and the like is required to be controlled to be 0.040 ~ 0.070.070 percent, the phosphorus content of the end point of the converter is controlled to be within 0.030 percent by the traditional converter smelting operation method, the ferrophosphorus alloy needs to be added in the tapping process, and the steelmaking alloy cost is increased.

The first is a phosphorus-containing steel smelting method of patent application No. 200410047045.0, in which, the converter adopts smelting operations of rapid temperature rise to remove carbon and maintain phosphorus and produce high phosphorus slag, at the beginning of blowing, the binary alkalinity is 1.0 ~ 2.5.5, 0.5 ~ 45.0.26 kg/ton steel of phosphorus iron ore or phosphorus ore is added into the converter, at the later stage of blowing, the slag alkalinity is controlled according to 3.0 ~ 4.0.0, 1.0 ~ 30.0.0 kg/ton steel of phosphorus iron ore or phosphorus ore is added into the converter liquid steel, the method uses the adding amount of phosphorus ore (or phosphorus iron ore) to control the difficulty, the use cost is high, the smelting final slag alkalinity is 3.0 ~ 4.0.0, and the consumption of slag is high.

The second method is a top-bottom combined blown converter phosphorus-containing steel smelting method with the patent application number of 201410334836.5, active lime and light-burned dolomite are respectively added according to the proportion of 7 ~ 8 kg/ton steel within 1 ~ 3min of the converter blowing, the alkalinity is controlled according to 1.0 ~ 2.0.0, iron-containing material carbon balls (free C: 8% ~ 13% and Fe is more than or equal to 50%) are added according to 5 ~ 6 kg/ton steel within 1min after delay, the end point phosphorus is controlled to be 0.05% ~ 0.075.075%, the method uses the iron carbon balls with higher carbon content to increase the oxygen consumption, the carbon-oxygen start rapid reaction period is 3 ~ 4min of blowing, and the adding of the iron carbon balls is not beneficial to smelting control and easy to splash.

The third is converter smelting method of phosphorus-containing steel with patent application number 201110240361.X, which controls the basicity of slag to be 2.6-2.8, the adding amount of active white ash ton steel to be 14-30kg, the adding amount of light-burned dolomite ton steel to be 16-35kg and the final phosphorus content to be about 0.030% by controlling the lance position of an oxygen lance and the oxygen supply strength according to the silicon content of molten iron, and reduces the adding amount of phosphorus and iron. The method has high consumption of active lime and light-burned dolomite and low control of the end point phosphorus content.

And the fourth method is a method for controlling the phosphorus content of molten steel at the end point of the converter, which is disclosed in patent application No. 201610622221.1, wherein the last furnace is used for dephosphorization and steelmaking normally, slag is retained according to the required phosphorus content, then phosphorus-containing steel is smelted, all furnace slag is poured after the phosphorus-containing steel is smelted, the next furnace is used for dephosphorization and steelmaking normally, slag is splashed to protect the furnace lining, and the steps are carried out alternately. The method can not continuously smelt the phosphorus-containing steel which is poured for a long time in one converter, has great influence on the production rhythm and production organization of the subsequent process, and the furnace condition maintenance of the converter is not facilitated by the furnace separation splashing.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention provides a control method which can reduce the consumption of slag charge and alloy and ensure that a converter can continuously and stably smelt the phosphorus-containing steel.

The technical scheme adopted by the invention for solving the technical problems is as follows: a control method for smelting high-phosphorus steel by a converter comprises the following steps:

firstly, active lime and light burned dolomite are added once within 5min of converter blowing, the adding amount of the active lime is 2 ~ kg/ton steel, the adding amount of the light burned dolomite is 7 ~ kg/ton steel, the alkalinity of final slag is controlled to be 2.0 ~.5, the oxygen pressure in the smelting process is 0.85 ~.00 Mpa, an oxygen lance adopts a high-low lance position in the blowing process, the high lance position is firstly opened for oxygen ignition in the early stage of the blowing process, then the low lance position is heated to melt slag and waste steel, the lance position is properly improved in the middle stage of the blowing process to prevent drying, the carbon is pulled at the low lance position in the later stage of the blowing process, the temperature of the end point carbon is controlled, the blowing lance position is 100 ~ mm lower than that of a normal dephosphorization furnace, the lance position in the process is controlled according to the principle that the slag is not foamed, does not return to dry, is not sprayed, the slag is quickly heated, the slag is uniformly, the temperature is controlled to be within 1610 ℃ to 0.90 ℃ in the later stage of the blowing oxygen pressure, the oxygen pressure is controlled to be 0.90.00 second, the oxygen addition is forbidden to be completed before the cold oxygen blowing process is completed in at least 5970 seconds;

and secondly, controlling the C to be 0.04 ~ 0.09.09% at the end point of the converter, controlling the tapping temperature to be 1645 ℃, ~ 1685 ℃ and controlling the P to be 0.040 ~ 0.070.070% at the end point, and adding ferrophosphorus for fine adjustment if the end point phosphorus does not reach the target component of the steel grade.

Thirdly, pouring part of slag after steel is discharged, adding light-burned dolomite for slag splashing and protecting the furnace, determining whether slag needs to be poured according to the slag amount condition after slag splashing, controlling the slag amount to be 3 ~ 5t, and smelting the phosphorus-containing steel in the next furnace.

If the upper furnace is used for smelting non-phosphorus-containing steel, the proportion of waste steel is adjusted according to the temperature of molten iron components (Si: 0.20 ~ 0.60% and P: 0.090 ~ 0.120.120% and the temperature 1270 ~ 1360%) when the lower furnace is used for smelting phosphorus-containing steel), the cooling cold charge is controlled within 1t in the blowing process, less cold charge is added to be beneficial to phosphorus preservation, the end point phosphorus of the steel type is required to be controlled to be 0.040 ~ 0.070.070%, the dephosphorization rate is controlled to be 40 ~ 65%, slag splashing is carried out after the steel is discharged from the non-phosphorus-containing steel, whether slag pouring is needed or not is determined according to the slag amount after slag splashing, the slag amount is controlled to be 3 ~ 5t, and the next furnace is prepared for smelting phosphorus-containing steel.

The invention has the beneficial effects that: the converter adopts a slag-remaining and slag-reducing mode for smelting, so that the consumption of slag making materials and ferrophosphorus is reduced, the iron loss brought away by large slag quantity is reduced, an oxygen lance adopts a high-low lance position in the blowing process, and the carbon temperature hit at the end point is controlled; the oxygen blowing time is shortened in the large oxygen pressure smelting, and the production cost is reduced. When non-phosphorus-containing steel is smelted in the converter, the proportion of scrap steel is reasonably matched according to the component temperature of molten iron, and smooth conversion of continuously and stably smelting phosphorus-containing steel in the converter is ensured.

Drawings

FIG. 1 is a lance position control diagram of a converter blowing lance in example 1;

FIG. 2 is a lance position control diagram of a converter blowing oxygen lance in example 2;

FIG. 3 is a lance position control diagram of a converter blowing lance in example 3.

Detailed Description

The technical solution of the present invention is described in detail below with reference to examples.

[ example 1 ]

The 1215CW steel grade is produced by a 130t converter, the control requirements of the components of the finished product are that C is 0.04 ~ 0.08.08%, Si is less than or equal to 0.08%, Mn is 0.80 ~ 1.05.05%, P is 0.04 ~ 0.08.08%, and S is 0.26 ~ 0.35.35%.

The method comprises the specific steps of enabling the silicon content of molten iron to be 0.250%, the phosphorus content to be 0.100%, enabling the temperature of the molten iron to be 1275 ℃, enabling the scrap ratio to be 16.2%, enabling the slag amount to be about 4 tons after slag splashing in steel tapping of an upper furnace, enabling the active lime to be added for one time within 4min, enabling the light burned dolomite to be 1200kg (9.23 kg/t steel), enabling the oxygen pressure to be 0.85 ~ 0.90.90 MPa in the middle stage of blowing, enabling the lance position to be 1500mm (1650 mm in normal furnace), enabling the cold charge to be added for 0kg in all times, enabling the auxiliary lance to measure the TSC temperature to be 1615 ℃ when the oxygen blowing rate is 82%, enabling the oxygen pressure to be 0.98MPa in the later stage of blowing, enabling the carbon lance position to be 1200mm (1350 mm in normal furnace), enabling the carbon pulling time to be 78 seconds, enabling the end point temperature to be 1663 ℃, enabling the carbon to be 0.04% in the end point, enabling the phosphorus content to reach the target component control of the steel when the oxygen content of the oxygen reaches 82% of the oxygen, enabling the oxygen lance to be up to be 1200mm in the later stage, enabling the oxygen lance to be pulled for the later stage, enabling the oxygen lance to be pulled for 800mm, enabling the oxygen lance position to be 1800mm, enabling the oxygen lance to be pulled for continuous protection of the later stage, enabling the furnace to be pulled for.

[ example 2 ]

The 1214Bi steel grade produced by a 130t converter has the control requirements of the components of the finished product including 0.06 ~ 0.09.09% of C, less than or equal to 0.08% of Si, 1.22 ~ 1.30.30% of Mn, 0.04 ~ 0.08.08% of P and 0.26 ~ 0.34.34% of S, and the aims of rapidly decarbonizing and retaining phosphorus are achieved by reasonably matching the proportion of scrap steel according to the component temperature of molten iron and smelting in a slag-remaining and slag-reducing mode, improving the oxygen pressure of smelting, appropriately reducing the lance position of an oxygen lance and keeping phosphorus.

The method comprises the specific steps of enabling the silicon content of molten iron to be 0.319%, the phosphorus content to be 0.094%, enabling the molten iron temperature to be 1310 ℃, enabling the scrap ratio to be 19.8%, enabling the slag amount to be about 3 tons after slag splashing in the steel-feeding and tapping of an upper furnace, enabling the active lime to be added for one time within 4min, enabling the light-burned dolomite to be 1500kg (11.54 kg/t), enabling the oxygen pressure to be 0.87 ~ 0.91MPa in the middle stage of blowing, enabling the lance position to be 1550mm (1700 mm in the normal furnace), enabling the cold charge to be added for 320kg in all times, enabling a secondary lance to measure TSC temperature 1634 ℃ when oxygen is blown for 80%, enabling the oxygen pressure to be 0.96MPa in the later stage of oxygen blowing, enabling the lance position to be 1250mm (1400 mm in the normal furnace), enabling the carbon-drawing time to be 88 seconds, enabling the end point temperature to be 1683 ℃, enabling the end point carbon to be 0.06%, enabling the end point to be phosphorus to be 0.045%, enabling the dephosphorization rate to be 52.1%, supplementing ferrophosphorus to be 30 kg. ℃ after slag splashing, enabling the slag-feeding to be continued to be protected in the furnace, enabling the smelting process, enabling the lance position to be 1800mm, enabling the oxygen-blowing lance to be blown for the oxygen-drawing to be blown for the later stage, enabling the oxygen-drawing lance to be pulled for the later stage oxygen-drawing time, enabling the oxygen-drawing lance to be.

[ example 3 ]

The 1215YG steel grade is produced by a 130t converter, the control requirements of the components of the finished product are that C is 0.04 ~ 0.08.08%, Si is less than or equal to 0.08%, Mn is 1.25 ~ 1.38.38%, P is 0.04 ~ 0.08.08%, and S is 0.30 ~ 0.38.38%.

The method comprises the specific steps of enabling the silicon content of molten iron to be 0.512%, the phosphorus content to be 0.110%, enabling the temperature of the molten iron to be 1344 ℃, enabling the scrap ratio to be 22.9%, enabling the slag amount to be about 5 tons after slag splashing of steel discharged from an upper furnace, enabling active lime to be 477kg (3.67 kg/t steel) and lightly burned dolomite to be 1400kg (10.77 kg/t steel) after blowing for 4min, enabling the oxygen pressure to be 0.86 ~ 0.90MPa in the middle stage of blowing, enabling the position of a lance in the middle stage of blowing to be 1550mm (1700 mm in normal furnace), enabling cold materials to be 820kg in total, enabling the temperature of a secondary lance to be 1629 ℃ when oxygen is blown for 85%, enabling the oxygen pressure to be 0.94MPa in the later stage of blowing, enabling the position of a carbon lance to be 1250mm (1400 mm in normal furnace), enabling the carbon-pulling time to be 81 seconds, enabling the end point temperature of blowing to be 1680.05 ℃, enabling the end point carbon to be 0.05%, enabling the phosphorus to be 0.061% in the dephosphorization rate to be 44.5%, enabling the end point phosphorus content to reach the target component control, enabling the oxygen-lance to be equivalent to the target component control after tapping, enabling the oxygen-to be 1480.1800 second, enabling the lance to be blown to be continued to be below the lance after tapping, enabling the lance to be equivalent to.

In the embodiment, the silicon content of the molten iron is 0.250 ~ 0.512.512%, the phosphorus content is 0.094 ~ 0.110.110%, the temperature of the molten iron is 1275 ~ 1344 ℃, the scrap steel ratio is 16.2 ~ 22.9.9%, the converter adopts a slag-remaining and slag-reducing smelting mode, the slag-remaining amount is 3 ~ 5t, the active lime consumes 2.15 ~ 3.67.67 kg/t steel, the light-burned dolomite consumes 9.23 ~ 11.54/t steel, the lance position of the oxygen lance is 1200 ~ 1550mm, and the cold charge amount is 0 ~ 820kg, through the implementation of the steps, the end point carbon is 0.04 ~ 0.06.06%, the end point temperature is 1663 ~ 1683 ℃, the end point phosphorus is controlled at 0.045 ~ 0.061.061%, the dephosphorization rate is 43 ~ 52.1.1%, the consumption of slag-making materials and ferrophosphorus alloy is reduced, the iron loss is reduced by reducing the large slag amount, the oxygen pressure smelting is shortened in oxygen blowing time, and the production cost is reduced.