阅读说明：本技术 一种喷吹co2冶炼不锈钢过程的动态控制方法 (Blowing CO2Dynamic control method for stainless steel smelting process ) 是由 魏光升 周赟 朱荣 董凯 陈培敦 赵刚 任鑫 李伟峰 王春阳 陈一帆 于 2021-01-04 设计创作，主要内容包括：本发明提出一种喷吹CO-2冶炼不锈钢过程的动态控制方法,属于不锈钢冶炼技术领域。在不锈钢冶炼过程的氧化期根据熔池成分和温度动态调控CO-2喷吹流量,调控熔池碳-铬反应平衡。当熔池碳含量ω[C]≥1.5％时,根据脱碳需求混入一定量的CO-2,提升熔池搅拌性能并且强化熔池脱碳反应进行；当0.5％≤ω[C]＜1.5％时,根据熔池温度和成分调整供氧量和CO-2喷吹流量,持续脱碳的同时利用CO-2的吸热效应对炉内进行控温,降低炉衬耐材的高温熔损；当ω[C]＜0.5％时,根据钢液目标成分,计算出供氧量和CO-2喷吹流量,控制熔池整体氧化性,并通过混合喷吹N-2/Ar降低炉内CO分压,减少铬的氧化烧损。(The invention provides a method for blowing CO 2 A dynamic control method for a stainless steel smelting process belongs to the technical field of stainless steel smelting. Dynamically regulating and controlling CO according to components and temperature of a molten pool in an oxidation period of a stainless steel smelting process 2 Blowing flow and regulating and controlling the carbon-chromium reaction balance of the molten pool. When the carbon content in the molten pool is omega C]When the carbon content is more than or equal to 1.5 percent, a certain amount of CO is mixed according to the decarburization requirement 2 The stirring performance of the molten pool is improved and the decarburization reaction of the molten pool is enhanced; when the content of omega [ C is less than or equal to 0.5%]If less than 1.5%, adjusting oxygen supply and CO according to temperature and composition of molten pool 2 Blowing flow, continuous decarburization and utilization of CO 2 The temperature of the furnace is controlled by the heat absorption effect of the heat exchanger, so that the high-temperature melting loss of the refractory material of the furnace lining is reduced; when omega [ C ]]When the content is less than 0.5%, calculating oxygen supply and CO according to the target components of the molten steel 2 Blowing flow rate, controlling the whole oxidability of molten pool, and blowing N by mixing 2 Ar reduces CO partial pressure in furnace and oxygen of chromiumBurning loss.)

1. Blowing CO₂A method for dynamically controlling a process for smelting stainless steel, characterized in that the carbon content of the bath is controlled in accordance with the omega C content]The oxidation period of the smelting process is divided into 3 stages of a rapid decarburization period, a temperature control period and a deep decarburization period, wherein the carbon content of a molten pool in the rapid decarburization period is omega [ C ]]More than 1.5%, and the carbon content of the molten pool in the temperature control period is more than 0.5% and less than omega [ C%]Not more than 1.5 percent, and the carbon content of the molten pool in the deep decarburization stage is omega [ C%]Less than or equal to 0.5 percent, and dynamically adjusting CO in the 3 stages₂Blowing flow, regulating and controlling carbon-chromium reaction balance of molten pool, and CO₂The specific control method of the blowing flow is as follows:

during the rapid decarburization period, the molten metal entering the furnace is firstly determined according to the components and the amount W of the molten metal entering the furnace₀Target composition, target tap-off amount W_gCalculating the alloy addition W according to the alloy components_a(formula 1) based on the composition of the charged molten metal and the amount W of charged molten metal₀Alloy composition, alloy addition W_aCalculating the oxygen consumption phi of the stage_1-O2(equation 2) oxygen flow rate Q_1-O2(formula 3) and CO₂Consumption Φ_1-CO2(formula 4) CO₂Flow rate Q_1-CO2(formula 5), the composition of the metal liquid in the furnace comprises the carbon content omega [ C ] in the molten iron]₀Silicon content omega Si]₀Manganese content omega [ Mn ]]₀Phosphorus content omega P]₀And chromium content omega [ Cr ]]₀The target component comprises the carbon content omega [ C ] in the molten steel]_gSilicon content omega Si]_gManganese content omega [ Mn ]]_gPhosphorus content omega P]_gAnd chromium content omega [ Cr ]]_gThe alloy composition comprises a carbon content omega [ C ] in the alloy]_aSilicon content omega Si]_aManganese content omega [ Mn ]]_aPhosphorus content omega P]_aAnd chromium content omega [ Cr ]]_a；

Q_1-O2＝Φ_1-O2/t₁(formula 3)

Φ_1-CO2＝R_1-CO2×Φ_1-O2(formula 4)

Q_1-CO2＝Φ_1-CO2/t₁(formula 5)

Wherein, t₁Setting the smelting time for the rapid decarburization period, R_1-CO2Is a proportionality coefficient;

during the temperature control period, according to the condition of not blowing CO₂The conventional process at this stage the bath temperature T_{2-molten bath}And blowing CO₂Post desired control temperature T_{Temperature control}And the carbon content of the molten pool at this stage omega C]_{2-molten bath}Calculating CO₂Consumption Φ_2-CO2(formula 6) CO₂Flow rate Q_2-CO2(formula 7) and oxygen consumption amount Φ_2-O2(equation 8) oxygen flow rate Q_2-O2(formula 9);

Q_2-CO2＝Φ_2-CO2/t₂(formula 7)

Q_2-O2＝Φ_2-O2/t₂(formula 9)

Wherein, C_PIs the specific heat capacity of the molten steel, t₂Setting smelting time for a temperature control period;

during the deep decarburization period, the carbon content of the molten pool omega C is determined according to the deep decarburization period]_{3-molten bath}Calculating oxygen consumption with target component_3-O2(equation 10) oxygen flow rate Q_3-O2(formula 11) and CO₂Consumption Φ_3-CO2(formula 12) CO₂Flow rate Q_3-CO2(formula 13) and N₂Amount of Ar consumption Φ_3-N2/Ar(formula 14) N₂Flow rate of Ar/Q_3-N2/Ar(formula 15);

Q_3-O2＝Φ_3-O2/t₃(formula 11)

Φ_3-CO2＝R_3-CO2×Φ_3-O2(formula 12)

Q_3-CO2＝Φ_3-CO2/t₃(formula 13)

Φ_3-N2/Ar＝R_3-N2/Ar×Φ_3-O2(formula 14)

Q_3-N2/Ar＝Φ_3-N2/Ar/t₃(formula 15)

Wherein, t₃Setting the smelting time for the deep decarburization period, R_3-CO2And R_3-N2/ArIs a scaling factor.

2. The method of claim 1, wherein said CO is injected into said chamber₂Movement of stainless steel smelting processThe state control method is characterized in that the quick decarburization period is set with smelting time t₁The value is 15-25 min, and the temperature control period is set as the smelting time t₂The value is 6-18 min, and the smelting time t is set in the deep decarburization period₃The value is 15-30 min, and the proportionality coefficient R_1-CO2The value is 0.05-0.2, R_3-CO2The value is 0.05-0.1, R_3-N2/ArThe value is 1-3.

3. The method of claim 1, wherein said CO is injected into said chamber₂The dynamic control method for the stainless steel smelting process is characterized in that the components of the metal liquid entering the furnace and the amount of the metal liquid entering the furnace are obtained by a raw material acquisition system in a steelmaking control system, and the oxygen consumption, the oxygen flow and the CO are obtained₂Consumption, CO₂Flow rate and N₂Consumption of/Ar, N₂the/Ar flow is obtained by calculation of a data calculation system in the steelmaking control system, and the temperature of the molten pool and the carbon content of the molten pool are measured in real time by a temperature measurement sampling system in the steelmaking control system.

4. A CO injection according to claims 1-3₂The dynamic control method for the stainless steel smelting process is characterized in that the smelting raw material suitable for the method is dephosphorized molten iron or stainless steel mother liquor, and any two or more than two of high-carbon ferrochrome, low-carbon ferrochrome, stainless steel scrap and chromium ore are added.

5. A CO injection according to claims 1-3₂The dynamic control method for the stainless steel smelting process is characterized in that smelting furnaces suitable for the method comprise an AOD furnace, a VOD furnace, a KOBM furnace, a GOR furnace and a TSR furnace.

Technical Field

The invention mainly belongs to the technical field of stainless steel smelting, and particularly relates to CO blowing₂A dynamic control method for stainless steel smelting process.

Background

In recent years, with the increasing market demand of stainless steel, the domestic yield of stainless steel is greatly increased every year. The important theoretical basis of stainless steel production is 'decarbonization and chromium protection', namely carbon in molten iron needs to be reduced to a very low level, and chromium in the molten steel is ensured not to be oxidized into slag. Therefore, compared with the common steel smelting furnace, the stainless steel smelting furnace has the advantages of low oxygen supply intensity, insufficient stirring intensity, long smelting period and high temperature in the furnace, so that the decarburization rate of a molten pool in the smelting process is low, the melting loss of a lining refractory material at high temperature is serious, and the furnace life is generally not high.

A large number of studies have shown that CO is present under the reaction conditions of steelmaking₂As a weak oxidizing gas, has a certain decarburization capability, and CO₂The reaction with C, Fe element in molten steel is endothermic, and the CO produced is gas, relative to oxygen₂The steel-making process can effectively control the temperature of the molten pool, strengthen the stirring of the molten pool, improve the reaction dynamic condition of the molten pool and improve the smelting efficiency. Therefore, CO is dynamically regulated and controlled in the stainless steel smelting process₂The blowing amount can realize the effects of high-efficiency decarburization, shortening the smelting period and prolonging the furnace life. With CO₂The large amount of emission is the main cause of greenhouse effect, so CO is developed₂By using new technology, the CO is consumed₂And reduction of CO₂The discharge is of great significance.

Disclosure of Invention

In order to solve the above problems, the present invention provides a methodBlowing CO₂A dynamic control method for smelting stainless steel features that the oxidizing period of smelting process is divided into 3 stages, i.e. fast decarbonizing period, temp-controlling period and deep decarbonizing period, and the CO is dynamically regulated in 3 stages₂Blowing flow, and regulating and controlling carbon-chromium reaction balance of a molten pool; in the quick decarburization period, decarburization is carried out mainly by blowing oxygen, and simultaneously, a certain amount of CO is mixed according to the decarburization requirement₂The stirring performance of the molten pool is improved and the decarburization reaction of the molten pool is enhanced; during the temperature control period, the temperature of the molten pool is higher, and the oxygen supply amount and CO are adjusted according to the temperature and components of the molten pool₂Blowing flow, continuous decarburization and utilization of CO₂The temperature of the furnace is controlled by the heat absorption effect of the heat exchanger, so that the high-temperature melting loss of the refractory material of the furnace lining is reduced; in the deep decarburization period, the oxygen supply amount and CO are calculated according to the target components of the molten steel₂Blowing flow rate, controlling the whole oxidability of molten pool, and blowing N by mixing₂and/Ar reduces the partial pressure of CO in the furnace and reduces the oxidation burning loss of chromium.

The invention is realized by the following technical scheme:

blowing CO₂A method for dynamically controlling a process for smelting stainless steel, characterized in that the carbon content of the bath is controlled in accordance with the omega C content]The oxidation period of the smelting process is divided into 3 stages of a rapid decarburization period, a temperature control period and a deep decarburization period, wherein the carbon content of a molten pool in the rapid decarburization period is omega [ C ]]More than 1.5%, and the carbon content of the molten pool in the temperature control period is more than 0.5% and less than omega [ C%]Not more than 1.5 percent, and the carbon content of the molten pool in the deep decarburization stage is omega [ C%]Less than or equal to 0.5 percent, and dynamically adjusting CO in the 3 stages₂Blowing flow and regulating and controlling carbon-chromium reaction balance of a molten pool, wherein the specific control method comprises the following steps:

during the rapid decarburization period, the molten metal entering the furnace is firstly determined according to the components and the amount W of the molten metal entering the furnace₀Target composition, target tap-off amount W_gCalculating the alloy addition W according to the alloy components_a(formula 1) based on the composition of the charged molten metal and the amount W of charged molten metal₀Alloy composition, alloy addition W_aCalculating the oxygen consumption phi of the stage_1-O2(equation 2) oxygen flow rate Q_1-O2(formula 3) and CO₂Consumption Φ_1-CO2(formula 4) CO₂Flow rate Q_1-CO2(formula 5) the metal charged into the furnaceThe liquid component comprises carbon content omega C in molten iron]₀Silicon content omega Si]₀Manganese content omega [ Mn ]]₀Phosphorus content omega P]₀And chromium content omega [ Cr ]]₀The target component comprises the carbon content omega [ C ] in the molten steel]_gSilicon content omega Si]_gManganese content omega [ Mn ]]_gPhosphorus content omega P]_gAnd chromium content omega [ Cr ]]_gThe alloy composition comprises a carbon content omega [ C ] in the alloy]_aSilicon content omega Si]_aManganese content omega [ Mn ]]_aPhosphorus content omega P]_aAnd chromium content omega [ Cr ]]_a；

Q_1-O2＝Φ_1-O2/t₁(formula 3)

Φ_1-CO2＝R_1-CO2×Φ_1-O2(formula 4)

Q_1-CO2＝Φ_1-CO2/t₁(formula 5)

Wherein, t₁Setting the smelting time for the rapid decarburization period, R_1-CO2Is a proportionality coefficient;

during the temperature control period, according to the condition of not blowing CO₂The conventional process at this stage the bath temperature T_{2-molten bath}And blowing CO₂Post desired control temperature T_{Temperature control}And the initial carbon content omega C of the molten pool at this stage]_{2-molten bath}Calculating CO₂Consumption Φ_2-CO2(formula 6) CO₂Flow rate Q_2-CO2(formula 7) and oxygen consumption amount Φ_2-O2(equation 8) oxygen flow rate Q_2-O2(formula 9);

Q_2-CO2＝Φ_2-CO2/t₂(formula 7)

Q_2-O2＝Φ_2-O2/t₂(formula 9)

Wherein, C_PIs the specific heat capacity of the molten steel, t₂Setting smelting time for a temperature control period;

during the deep decarburization period, the initial carbon content of the molten pool omega C is determined according to the stage]_{3-molten bath}Calculating oxygen consumption with target component_3-O2(equation 10) oxygen flow rate Q_3-O2(formula 11) and CO₂Consumption Φ_3-CO2(formula 12) CO₂Flow rate Q_3-CO2(formula 13) and N₂Amount of Ar consumption Φ_3-N2/Ar(formula 14) N₂Flow rate of Ar/Q_3-N2/Ar(formula 15);

Q_3-O2＝Φ_3-O2/t₃(formula 11)

Φ_3-CO2＝R_3-CO2×Φ_3-O2(formula 12)

Q_3-CO2＝Φ_3-CO2/t₃(formula 13)

Φ_3-N2/Ar＝R_3-N2/Ar×Φ_3-O2(formula 14)

Q_3-N2/Ar＝Φ_3-N2/Ar/t₃(formula 15)

Wherein, t₃Setting the smelting time for the deep decarburization period, R_3-CO2And R_3-N2/ArIs a scaling factor.

Further, the quick decarburization period is set to be the smelting time t₁The value is 15-25 min, and the temperature control period is set as the smelting time t₂The value is 6-18 min, and the smelting time t is set in the deep decarburization period₃The value is 15-30 min, and the proportionality coefficient R_1-CO2The value is 0.05-0.2, R_3-CO2The value is 0.05-0.1, R_3-N2/ArThe value is 1-3.

Furthermore, the components of the metal liquid entering the furnace, the amount of the metal liquid entering the furnace and the components of the alloy are obtained by a raw material acquisition system in a steelmaking control system, and the oxygen consumption, the oxygen flow and the CO are obtained₂Consumption, CO₂Flow rate and N₂Consumption of/Ar, N₂the/Ar flow is obtained by calculation of a data calculation system in the steelmaking control system, and the temperature of the molten pool and the carbon content of the molten pool are measured in real time by a temperature measurement sampling system in the steelmaking control system.

Further, the CO injection₂The dynamic control method for the stainless steel smelting process is suitable for smelting raw materials which are dephosphorized molten iron or stainless steel mother liquor and are mixed with any two or more than two of high-carbon ferrochrome, low-carbon ferrochrome, stainless steel scrap and chromium ore.

Further, the CO injection₂The smelting furnace suitable for the dynamic control method for the stainless steel smelting process comprises an AOD furnace, a VOD furnace, a KOBM furnace, a GOR furnace and a TSR furnace.

The invention has the beneficial technical effects that:

according to the invention, CO is dynamically regulated and controlled according to the components and temperature of a molten pool in the stainless steel smelting process₂The blowing flow improves the stirring performance of the molten pool when the carbon content of the molten pool is higher, accelerates the decarburization of the molten pool and improves the smelting efficiency. Meanwhile, the temperature in the furnace is effectively controlled in the smelting process, the high-temperature melting loss of the refractory material of the furnace lining is reduced, and the furnace life is prolonged. When the carbon content of the molten pool is lower, the oxidability of the molten pool is effectively controlled, the chromium oxidation burning loss in the molten steel is reduced, and the chromium metal yield is improved.

Detailed Description

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

On the contrary, the invention is intended to cover alternatives, modifications, equivalents and alternatives which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, certain specific details are set forth in order to provide a better understanding of the present invention. It will be apparent to one skilled in the art that the present invention may be practiced without these specific details.

Example 1

The invention is applied to the refining process of a 180t AOD furnace, and the smelting product is 304 stainless steel. The smelting raw materials are stainless steel mother liquor and high-carbon ferrochrome, and the smelting time t is set in the quick decarburization period₁Setting the smelting time t for 15min in the temperature control period₂Setting smelting time t at deep decarburization period for 8min₃Is 15min, the proportionality coefficient R_1-CO2Value of 0.1, R_3-CO2A value of 0.05, R_3-N2/ArThe value is 2. The specific smelting steps are as follows:

(1) the compositions of the stainless steel mother liquor and the high-carbon ferrochrome obtained by a raw material collecting system in the steelmaking control system are shown in tables 1 and 2, the weight of the stainless steel mother liquor is 175t, the preset target composition is shown in table 3, and the target steel tapping amount is 180 t.

TABLE 1 stainless Steel mother liquor composition

Composition (I)

C

Si

Mn

P

Cr

Fe

Content (wt.)

2.3％

0.20％

0.50％

0.03％

16.2％

79.77％

TABLE 2 high carbon ferrochrome composition

Composition (I)

C

Si

Mn

P

Cr

Fe

Content (wt.)

8.0％

3.0％

0.10％

0.02％

58.2％

30.68％

TABLE 3 target composition

Composition (I)

C

Si

Mn

P

Cr

Fe

Content (wt.)

0.03％

0.45％

1.0％

0.02％

18.1％

80.4％

(2) 0-15 min, a rapid decarburization period, wherein the alloy addition amount is 8.1t calculated by a data calculation system according to the (formula 1) - (formula 5), and the oxygen flow rate is 178.8Nm at the stage³/min，CO₂The flow rate was 17.9Nm³/min。

(3) 15-23 min, temperature control period, real-time measuring by temperature measurement sampling system to obtain CO non-blowing₂Temperature control period of the traditional processThe beam temperature was 1605 ℃ and the initial carbon content of the bath at this stage was 1.38%, now by blowing CO₂Controlling the temperature at 1580 deg.C, and calculating the oxygen flow of 197.9Nm according to the formulas 6-9³/min，CO₂The flow rate was 28.4Nm³/min。

(4) 23-31 min, in the deep decarburization period, measuring the initial carbon content of the molten pool in the stage to be 0.43% by a temperature measurement sampling system in real time, and calculating the oxygen flow of 49.2Nm in the stage according to the formulas (10) to (15)³/min，CO₂The flow rate is 2.5Nm³/min，N₂The flow rate was 98.3Nm³/min。

(5) And (4) entering a reduction period after 31min, adding deoxidized alloy, and blowing pure Ar for reduction smelting.

Example 2

The invention is applied to the process of smelting stainless steel by using 70t TSR, and the smelting product is 410 stainless steel. The smelting raw materials are dephosphorized molten iron and high-carbon ferrochrome, and the smelting time t is set in the quick decarburization period₁Setting the smelting time t for 20min in the temperature control period₂Setting smelting time t for 10min in deep decarbonization period₃Is 22min, the proportionality coefficient R_1-CO2Value of 0.1, R_3-CO2The value of R is 0.06_3-N2/ArThe value is 2. The specific smelting steps are as follows:

(1) the components of the dephosphorized molten iron and the high-carbon ferrochrome obtained by a raw material collecting system in the steelmaking control system are shown in tables 1 and 2, the weight of the stainless steel mother liquor is 66t, the preset target components are shown in table 3, and the target steel tapping amount is 70 t.

TABLE 1 dephosphorization of molten iron composition

Composition (I)

C

Si

Mn

P

Cr

Fe

Content (wt.)

3.54％

0.41％

0.29％

0.02％

0％

95.71％

TABLE 2 high carbon ferrochrome composition

Composition (I)

C

Si

Mn

P

Cr

Fe

Content (wt.)

7.45％

3.52％

0.15％

0.02％

49.53％

39.33％

TABLE 3 target composition

Composition (I)

C

Si

Mn

P

Cr

Fe

Content (wt.)

0.02％

0.40％

0.35％

0.02％

13.1％

86.11％

(2) 0-20 min, fast decarburization period, from dataThe calculation system calculates the alloy addition amount according to the (formula 1) to (formula 5) to obtain the alloy addition amount of 20.6t, and the oxygen flow rate of 172.2Nm in the stage³/min，CO₂The flow rate was 17.2Nm³/min。

(3) 20-30 min, temperature control period, real-time measuring by temperature measuring and sampling system to obtain CO not blown₂The temperature of the traditional process is controlled to be 1605 ℃ at the end of the temperature control period and the initial carbon content of a molten pool is 1.38% at the stage, and CO is blown₂Controlling the temperature at 1580 deg.C, and calculating the oxygen flow rate at 84.2Nm according to the formulas 6-9³/min，CO₂The flow rate was 10.7Nm³/min。

(4) 30-52 min, in the deep decarburization period, measuring the initial carbon content of the molten pool in the stage to be 0.43% by a temperature measurement sampling system in real time, and calculating the oxygen flow of 18.6Nm in the stage according to the formulas (10) - (15)³/min，CO₂The flow rate is 1.1Nm³/min，N₂The flow rate was 37.1Nm³/min。

(5) And (4) after 52min, entering a reduction period, adding deoxidized alloy, and blowing pure Ar for reduction smelting.