阅读说明：本技术 一种低钒铁水转炉炼钢的控制方法及其应用 (Control method for converter steelmaking of low-vanadium molten iron and application thereof ) 是由 李亚厚 靳刚强 孙力 王琪 车晓锐 高艳甲 于 2020-12-16 设计创作，主要内容包括：本发明属于冶金技术领域,尤其涉及一种低钒铁水转炉炼钢的控制方法及其应用。本发明中所用低钒铁水包括以下质量百分比的化学成分：C：4.0～4.4％,V：0.10～0.15％,Si+Ti：0.2～0.5％,P：≤0.13％,S：≤0.06％,其余为铁和不可避免的杂质元素。本发明在不改变原工艺路线的情况下,通过对转炉炼钢过程中的工艺控制,将低钒铁水转炉冶炼终点钢水的余钒回收率提高至9％～12％,实现了钒元素的有效回收,降低了后续合金化过程中钒合金的用量,降低了炼钢成本。(The invention belongs to the technical field of metallurgy, and particularly relates to a control method for converter steelmaking of low-vanadium molten iron and application thereof. The low-vanadium molten iron used in the invention comprises the following chemical components in percentage by mass: c: 4.0-4.4%, V: 0.10-0.15%, Si + Ti: 0.2-0.5%, P: less than or equal to 0.13 percent, S: less than or equal to 0.06 percent, and the balance of iron and inevitable impurity elements. Under the condition of not changing the original process route, the method improves the residual vanadium recovery rate of the molten steel at the smelting end point of the converter with the low-vanadium molten iron to 9-12% by process control in the converter steelmaking process, realizes effective recovery of vanadium element, reduces the dosage of vanadium alloy in the subsequent alloying process, and reduces the steelmaking cost.)

1. The control method for converter steelmaking of the low-vanadium molten iron is characterized in that the low-vanadium molten iron comprises the following chemical components in percentage by mass:

c: 4.0-4.4%, V: 0.10-0.15%, Si + Ti: 0.2-0.5%, P: less than or equal to 0.13 percent, S: less than or equal to 0.06 percent, and the balance of iron and inevitable impurity elements;

the low-vanadium molten iron is smelted in a top-blown converter by adopting a single slag process, and the method specifically comprises the following steps:

s1, charging scrap steel into the converter, adding the low-vanadium molten iron, shaking the converter, and starting blowing; the mass ratio of the scrap steel to the molten iron is 2-4: 100;

s2, adding a slag making material and controlling the lance position of the oxygen lance to be 1.3-1.4 m at the stage of starting blowing for 4-6 min;

adding slag making materials and controlling the lance position of the oxygen lance to be 1.2-1.4 m after S3 and S2 are finished for 4-6 min;

and controlling the lance position of the oxygen lance to be 1.0-1.1 m for 60-90S after S4 and S3 are finished, and tapping after blowing is finished to obtain end-point molten steel.

2. The method for controlling the converter steelmaking of the low-vanadium molten iron according to claim 1, wherein the number of the oxygen lance jet holes of the converter used for the steelmaking is 3, the flow velocity of oxygen is controlled to be Mach 2.0-2.4, and the pressure of the oxygen lance is controlled to be 0.9-1.1 MPa in the blowing process.

3. The method for controlling the converter steelmaking of the low-vanadium molten iron as claimed in claim 1, wherein the temperature of the low-vanadium molten iron blended in S1 is 1300-1350 ℃.

4. The method for controlling converter steelmaking of low-vanadium molten iron according to claim 1, wherein the components of the slag-making materials added in S2 and S3 are lime and other slag-making materials.

5. The control method for converter steelmaking by using the low vanadium molten iron as claimed in claim 4, wherein the other slagging material is one or more of light burned dolomite, raw dolomite and fluorite.

6. The method for controlling converter steelmaking of the low vanadium molten iron according to claim 4, wherein the total addition amount of the lime is 20 to 25 kg/ton of steel, and the total addition amount of the other slag-making materials is 10 to 15 kg/ton of steel.

7. The control method for converter steelmaking by using the low vanadium molten iron as claimed in claim 6, wherein 1/2-2/3 of the total amount of the lime is added in the stage of S2, and the rest of the lime is added in the stage of S3.

8. The control method for converter steelmaking by using the low-vanadium molten iron as claimed in claim 6, wherein 1/2-2/3 of the total addition amount of the other slag forming materials is added in the stage of S2, and the rest of the other slag forming materials are added in the stage of S3.

9. The application of the control method for converter steelmaking of the low-vanadium molten iron as claimed in any one of claims 1 to 8 in the production of the HRB400E steel grade is characterized in that the HRB400E steel grade is produced by using the final molten steel.

10. The use of claim 9, wherein the element content in the HRB400E steel grade comprises, in weight percent: c: 0.2 to 0.25%, Si: 0.35-0.6%, Mn: 0.125-0.160%, V: 0.03-0.05% and P is less than or equal to 0.045%; less than or equal to 0.045 percent of S, and the balance of Fe and inevitable impurity elements.

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a control method for converter steelmaking of low-vanadium molten iron and application thereof.

Background

Vanadium is a precious metal, has wide application range and high economic value, is an extremely important industrial raw material, can be widely used in the fields of steel, chemical industry, aerospace, electronic industry, biology and agriculture, is extremely dispersed in the natural world and often coexists with other metals, vanadium-titanium magnetite is a main mineral resource of vanadium, iron and titanium are coexisted, and vanadium slag is obtained by oxidizing and blowing after the vanadium is generally smelted into molten iron and is used as a main raw material for producing vanadium products.

In the process of smelting low vanadium-containing molten iron (the mass percentage of vanadium element is 0.1-0.15%) in a blast furnace, the vanadium slag obtained after vanadium extraction in the converter is low in grade and is not suitable for further processing of vanadium chemical enterprises, so the low vanadium-containing molten iron is directly used for steelmaking without vanadium extraction operation, and the vanadium element in the molten iron is oxidized into V in the blowing process₂O₅The vanadium is transferred into the slag, the waste of vanadium element is caused, the content of residual vanadium at the blowing end is too low, a large amount of vanadium alloy is required to be added in the subsequent alloying process, and the steel-making cost is increased.

Disclosure of Invention

The invention provides a control method for converter steelmaking of low-vanadium molten iron and application thereof, aiming at the technical problems that in the molten iron, the content of vanadium in the molten iron is too low, so that the original vanadium in the molten iron is wasted, and a large amount of vanadium alloy is required to be added in the later alloying process, so that the production cost is increased.

In order to achieve the purpose of the invention, the embodiment of the invention adopts the following technical scheme:

a control method for converter steelmaking of low-vanadium molten iron comprises the following steps: the low-vanadium molten iron comprises the following chemical components in percentage by mass:

c: 4.0-4.4%, V: 0.10-0.15%, Si + Ti: 0.2-0.5%, P: less than or equal to 0.13 percent, S: less than or equal to 0.06 percent, and the balance of iron and inevitable impurity elements;

the low-vanadium molten iron is smelted in a top-blown converter by adopting a single slag process, and the method specifically comprises the following steps:

s1, charging scrap steel into the converter, adding the low-vanadium molten iron, shaking the converter, and starting blowing; the ratio of the scrap steel to the molten iron is 2-4: 100;

s2, adding a slag making material and controlling the lance position of the oxygen lance to be 1.3-1.4 m at the stage of starting blowing for 4-6 min;

adding slag making materials and controlling the lance position of the oxygen lance to be 1.2-1.4 m after S3 and S2 are finished for 4-6 min;

controlling the lance position of the oxygen lance to be 1.0-1.1 m for 60-90S after S4 and S3 are finished, and tapping after blowing is finished to obtain end-point molten steel;

the lance position of the oxygen lance is the distance from the nozzle to the liquid level of molten iron.

Compared with the prior art: according to the invention, through the measures of controlling the process of converter steelmaking, reducing the addition of scrap steel, improving the lance position before the converting end point, shortening the lance-dropping converting time before the converting end point and the like, the converter end point temperature and the carbon content are improved, the converter end point temperature is controlled to 1650-1670 ℃, the percentage content of carbon is controlled to 0.06-0.10%, the vanadium element in molten iron is prevented from entering the slag, and the V in the slag at the later stage of converting is promoted₂O₅The reduction of the method improves the residual vanadium content of the molten steel at the blowing end point, realizes the effective recovery of vanadium element, reduces the dosage of vanadium alloy in the subsequent alloying process and reduces the steelmaking cost.

Preferably, the number of the oxygen lance holes is 3, the oxygen flow velocity is controlled to be 2.0-2.4 Mach in the blowing process, and the pressure of the oxygen lance is 0.9-1.1 Mpa.

The optimized oxygen flow rate and oxygen pressure can stir the smelting system, accelerate the dissolution of the slag melting agent, control the oxidation reaction rate of the smelting system, ensure the stability of the slagging process, avoid the occurrence of slag splashing and protect the furnace lining.

Preferably, the temperature of the low-vanadium iron water blended in the S1 is 1300-1350 ℃.

The optimized molten iron temperature can provide proper initial heat for converter steelmaking, the oxidizing and slagging efficiency of impurity elements in the molten iron can ensure the stability of the steelmaking process, and the splashing can be avoided.

Preferably: the slag-making materials added in S2 and S3 comprise lime and other slag-making materials, and the other slag-making materials comprise one or more of light-burned dolomite, raw dolomite, fluorite and the like; the total mass ratio of lime added in the blowing process is 20-25 kg/ton steel, and the total mass ratio of other slag making materials added in the blowing process is 10-15 kg/ton steel.

The preferable mass proportion of the converter lime can remove elements such as impurity S, P in the molten iron to the maximum extent, improve the quality of slag without causing waste of slag-making materials, and the preferable mass proportion of other slag-making materials can accelerate lime dissolution, improve the fluidity of molten slag, improve the slag forming speed, protect the slag forming process, prevent splashing and protect a furnace lining.

Preferably, 1/2-2/3 of the total amount of the lime is added in the S2 stage, and the rest lime is added in the S3 stage; 1/2-2/3 of the total amount of other slagging materials is added in the S2 stage, and the rest other slagging materials are added in the S3 stage.

The preferable slag-making material adding system can maintain the stability of the whole smelting system, can quickly dissolve the slag-melting material, accelerate the slag-forming efficiency, prevent splashing and protect the furnace lining.

The embodiment of the invention also provides application of the low-vanadium molten iron converter steelmaking control method in production of HRB400E steel, and HRB400E steel is produced by using the blowing end molten steel. And transferring the end-point molten steel to a post-process, and carrying out LF refining and continuous casting to produce the HRB400E section steel.

Preferably, the element content in the HRB400E steel grade comprises the following components in percentage by weight: c: 0.2 to 0.25%, Si: 0.35-0.6%, Mn: 0.125-0.160%, V: 0.03-0.05% and P is less than or equal to 0.045%; less than or equal to 0.045 percent of S, and the balance of Fe and inevitable impurity elements.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

A control method for converter steelmaking of low-vanadium molten iron comprises the following elements in percentage by mass: c: 4.31%, Si + Ti: 0.34%, P: 0.118%: s: 0.043%, V: 0.137%, and the balance of iron and inevitable impurity elements;

s1, filling 2 tons of scrap steel into the converter, adding 99 tons of low-vanadium molten iron containing the elements in percentage by mass at 1315 ℃, shaking the converter to start oxygen supply and blowing, wherein the number of oxygen lance holes is 3, the oxygen flow rate is Mach 2.2, and the pressure is 1.0 MPa;

s2, controlling the lance position of the oxygen lance to be kept at 1.4m at a stage of 5min after the blowing begins, and adding 1050kg of lime and 600kg of a mixture of dolomite and fluorite in the blowing process;

controlling the lance position of the oxygen lance to be kept at 1.3m 6min after S3 and S2 are finished, keeping the original oxygen pressure and flow rate to continue blowing, and adding 1030kg of lime and 588kg of a mixture of light-burned dolomite and fluorite in the blowing process;

and controlling the lance position of the oxygen lance to be 1.1m 60S after S4 and S3 are finished, and tapping after blowing is finished to obtain end-point molten steel.

Measuring the carbon content, the temperature and the vanadium content of the obtained end-point molten steel, transferring the obtained end-point molten steel to a post-process, and producing HRB400E section steel after LF refining and continuous casting, wherein the HRB400E section steel specifically comprises the following components in percentage by mass: c: 0.2%, Si: 0.35%, Mn: 0.125%, V: 0.03%, P: 0.045%; s: 0.045%, and the balance of Fe and inevitable impurity elements.

Example 2

A control method for converter steelmaking of low-vanadium molten iron comprises the following elements in percentage by mass: c: 4.24%, Si + Ti: 0.28%, P: 0.121%: s: 0.039%, V: 0.126%, the balance being iron and inevitable impurity elements;

s1, filling 3 tons of scrap steel into the converter, adding 98 tons of low-vanadium molten iron containing the elements in percentage by mass at 1319 ℃, shaking the converter to start oxygen supply and blowing, wherein the number of oxygen lance holes is 3, the oxygen flow rate is Mach 2.3, and the pressure is 1.1 MPa;

s2, controlling the lance position of the oxygen lance to be kept at 1.3m at a stage of 6min after the blowing begins, and adding 1100kg of lime and 750kg of a mixture of dolomite and fluorite in the blowing process;

controlling the lance position of the oxygen lance to be kept at 1.2m after 4min after S3 and S2 are finished, keeping the original oxygen pressure and flow rate to continue blowing, and adding 1056kg of lime and 720kg of a mixture of raw dolomite and fluorite in the blowing process;

and controlling the lance position of the oxygen lance to be 1.0m 75S after S4 and S3 are finished, and tapping after blowing is finished to obtain end-point molten steel.

Measuring the carbon content, the temperature and the vanadium content of the obtained end-point molten steel, transferring the obtained end-point molten steel to a post-process, and producing HRB400E section steel after LF refining and continuous casting, wherein the HRB400E section steel specifically comprises the following components in percentage by mass: c: 0.22%, Si: 0.40%, Mn: 0.135%, V: 0.04%, P: 0.04 percent; s: 0.04% and the balance of Fe and inevitable impurity elements.

Example 3

A control method for converter steelmaking of low-vanadium molten iron comprises the following elements in percentage by mass: c: 4.27%, Si + Ti: 0.19%, P: 0.114%: s: 0.034%, V: 0.122%, the balance being iron and inevitable impurity elements;

s1, filling 2 tons of scrap steel into the converter, adding 99 tons of low-vanadium molten iron containing the elements in percentage by mass at 1326 ℃, shaking the converter to start oxygen supply and blowing, wherein the number of oxygen lance holes is 3, the oxygen flow rate is Mach 2.2, and the pressure is 1.1 MPa;

s2, controlling the lance position of the oxygen lance to be kept at 1.3m at a stage of 4min after the blowing is started, and adding 1630kg of lime and 790kg of a mixture of dolomite and fluorite in the blowing process;

controlling the lance position of the oxygen lance to be kept at 1.4m after S3 and S2 are finished for 5min, keeping the original oxygen pressure and flow rate to continue blowing, and adding 845kg of lime and 398kg of a mixture of raw dolomite and light burned dolomite in the blowing process;

and controlling the lance position of the oxygen lance to be 1.1m 90S after S4 and S3 are finished, and tapping after blowing is finished to obtain end-point molten steel.

Measuring the carbon content, the temperature and the vanadium content of the obtained end-point molten steel, transferring the obtained end-point molten steel to a post-process, and producing HRB400E section steel after LF refining and continuous casting, wherein the HRB400E section steel specifically comprises the following components in percentage by mass: c: 0.24%, Si: 0.45%, Mn: 0.145%, V: 0.05%, P: 0.03 percent; s: 0.04% and the balance of Fe and inevitable impurity elements.

Comparative example 1

A control method for converter steelmaking of low-vanadium molten iron comprises the following elements in percentage by mass: c: 4.27%, Si + Ti: 0.19%, P: 0.114%: s: 0.034%, V: 0.122%, the balance being iron and inevitable impurity elements;

s1, filling 7 tons of scrap steel into the converter, adding 99 tons of low-vanadium molten iron containing the elements in percentage by mass at 1326 ℃, shaking the converter to start oxygen supply and blowing, wherein the number of oxygen lance holes is 3, the oxygen flow rate is Mach 2.2, and the pressure is 1.1 MPa;

s2, controlling the lance position of the oxygen lance to be kept at 1.3m at a stage of 4min after the blowing is started, and adding 1630kg of lime and 790kg of a mixture of dolomite and fluorite in the blowing process;

controlling the lance position of the oxygen lance to be kept at 1.4m after S3 and S2 are finished for 5min, keeping the original oxygen pressure and flow rate to continue blowing, and adding 845kg of lime and 398kg of a mixture of raw dolomite and light burned dolomite in the blowing process;

and controlling the lance position of the oxygen lance to be 1.1m 90S after S4 and S3 are finished, and tapping after blowing is finished to obtain end-point molten steel.

Measuring the carbon content, the temperature and the vanadium content of the obtained end-point molten steel, transferring the obtained molten steel to a post-process, and producing HRB400E section steel after LF refining and continuous casting, wherein the HRB E section steel specifically comprises the following components in percentage by mass: c: 0.24%, Si: 0.45%, Mn: 0.145%, V: 0.05%, P: 0.03 percent; s: 0.04% and the balance of Fe and inevitable impurity elements.

Comparative example 2

A control method for converter steelmaking of low-vanadium molten iron comprises the following elements in percentage by mass: c: 4.27%, Si + Ti: 0.19%, P: 0.114%: s: 0.034%, V: 0.122%, the balance being iron and inevitable impurity elements;

s1, filling 2 tons of scrap steel into the converter, adding 99 tons of low-vanadium molten iron containing the elements in percentage by mass at 1326 ℃, shaking the converter to start oxygen supply and blowing, wherein the number of oxygen lance holes is 3, the oxygen flow rate is Mach 2.2, and the pressure is 1.1 MPa;

s2, controlling the lance position of the oxygen lance to be kept at 1.3m at a stage of 4min after the blowing is started, and adding 1630kg of lime and 790kg of a mixture of dolomite and fluorite in the blowing process;

controlling the lance position of the oxygen lance to be kept at 1.4m 6min after S3 and S2 are finished, keeping the original oxygen pressure and flow rate to continue blowing, and adding 845kg of lime and 398kg of a mixture of raw dolomite and light burned dolomite in the blowing process;

and controlling the lance position of the oxygen lance to be 0.9m 90S after S4 and S3 are finished, and tapping after blowing is finished to obtain end-point molten steel.

Measuring the carbon content, the temperature and the vanadium content of the obtained end-point molten steel, transferring the obtained end-point molten steel to a post-process, and producing HRB400E section steel after LF refining and continuous casting, wherein the HRB400E section steel specifically comprises the following components in percentage by mass: c: 0.24%, Si: 0.45%, Mn: 0.145%, V: 0.05%, P: 0.03 percent; s: 0.04% and the balance of Fe and inevitable impurity elements.

Comparative example 3

A control method for converter steelmaking of low-vanadium molten iron comprises the following elements in percentage by mass: c: 4.27%, Si + Ti: 0.19%, P: 0.114%: s: 0.034%, V: 0.122%, the balance being iron and inevitable impurity elements;

s1, filling 2 tons of scrap steel into the converter, adding 99 tons of low-vanadium molten iron containing the elements in percentage by mass at 1326 ℃, shaking the converter to start oxygen supply and blowing, wherein the number of oxygen lance holes is 3, the oxygen flow rate is Mach 2.2, and the pressure is 1.1 MPa;

s2, controlling the lance position of the oxygen lance to be kept at 1.6m at a stage of 4min after the blowing is started, and adding 1630kg of lime and 790kg of a mixture of dolomite and fluorite in the blowing process;

controlling the lance position of the oxygen lance to be kept at 1.4m 6min after S3 and S2 are finished, keeping the original oxygen pressure and flow rate to continue blowing, and adding 845kg of lime and 398kg of a mixture of raw dolomite and light burned dolomite in the blowing process;

and controlling the lance position of the oxygen lance to be 1.1m 90S after S4 and S3 are finished, and tapping after blowing is finished to obtain end-point molten steel.

Measuring the carbon content, the temperature and the vanadium content of the obtained end-point molten steel, transferring the obtained end-point molten steel to a post-process, and producing HRB400E section steel after LF refining and continuous casting, wherein the HRB400E section steel specifically comprises the following components in percentage by mass: c: 0.24%, Si: 0.45%, Mn: 0.145%, V: 0.05%, P: 0.03 percent; s: 0.04% and the balance of Fe and inevitable impurity elements.

Comparative example 4

A control method for converter steelmaking of low-vanadium molten iron. The low-vanadium molten iron comprises the following elements in percentage by mass: c: 4.27%, Si + Ti: 0.19%, P: 0.114%: s: 0.034%, V: 0.122%, the balance being iron and inevitable impurity elements;

s1, filling 2 tons of scrap steel into the converter, adding 99 tons of low-vanadium molten iron containing the elements in percentage by mass at 1326 ℃, shaking the converter to start oxygen supply and blowing, wherein the number of oxygen lance holes is 3, the oxygen flow rate is Mach 2.2, and the pressure is 1.1 MPa;

s2, controlling the lance position of the oxygen lance to be kept at 1.3m at a stage of 4min after the blowing is started, and adding 1630kg of lime and 790kg of a mixture of dolomite and fluorite in the blowing process;

controlling the lance position of the oxygen lance to be kept at 1.4m 6min after S3 and S2 are finished, keeping the original oxygen pressure and flow rate to continue blowing, and adding 845kg of lime and 398kg of a mixture of raw dolomite and light burned dolomite in the blowing process;

and (4) controlling the lance position of the oxygen lance to be 1.1m 180S after S4 and S3 are finished, and tapping after blowing is finished to obtain end-point molten steel.

Measuring the carbon content, the temperature and the vanadium content of the obtained end-point molten steel, transferring the obtained end-point molten steel to a post-process, and producing HRB400E section steel after LF refining and continuous casting, wherein the HRB400E section steel specifically comprises the following components in percentage by mass: c: 0.24%, Si: 0.45%, Mn: 0.145%, V: 0.05%, P: 0.03 percent; s: 0.04% and the balance of Fe and inevitable impurity elements.

Comparative example 5:

a control method for converter steelmaking of low-vanadium molten iron comprises the following elements in percentage by mass: c: 4.28%, Si + Ti: 0.37%, P: 0.114%: s: 0.041%, V: 0.128%, the balance being iron and inevitable impurity elements;

s1, filling 7 tons of scrap steel into the converter, adding 96 tons of low-vanadium molten iron containing the elements in percentage by mass at 1321 ℃, shaking the converter to start oxygen supply and blowing, wherein the number of oxygen lance holes is 3, the oxygen flow rate is Mach 2.2, and the pressure is 1.1 MPa;

s2, controlling the lance position of the oxygen lance to be kept at 1.6m at a stage of 5min after the blowing is started, and adding 1300kg of lime and 780kg of a mixture of dolomite and fluorite in the blowing process;

controlling the lance position of the oxygen lance to be kept at 1.4m after S3 and S2 are finished for 5min, keeping the original oxygen pressure and flow rate to continue blowing, and adding 620kg of lime and 468kg of a mixture of raw dolomite and light burned dolomite in the blowing process;

controlling the lance position of the oxygen lance to be 0.9m 180S after S4 and S3 are finished, and tapping after blowing is finished to obtain end-point molten steel;

measuring the carbon content, the temperature and the vanadium content of the obtained end-point molten steel, transferring the obtained end-point molten steel to a post-process, and producing HRB400E section steel after LF refining and continuous casting, wherein the HRB400E section steel specifically comprises the following components in percentage by mass: c: 0.24%, Si: 0.45%, Mn: 0.145%, V: 0.05%, P: 0.03 percent; s: 0.04% and the balance of Fe and inevitable impurity elements.

Examples of effects

The results of the end point temperature of the blowing, the carbon content, the vanadium content and the vanadium recovery rate of each example & comparative example are shown in table 1.

TABLE 1 Effect of the embodiment

The implementation effect in the table 1 shows that the mass percentage content of carbon in the molten steel obtained at the end point of the converter in the embodiment of the invention is 0.06-0.10%, the end point temperature is 1650-1670 ℃, and the vanadium recovery rate is 9-12%.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents or improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.