CN110042188B - Method for compensating converter blowing end point temperature - Google Patents
Method for compensating converter blowing end point temperature Download PDFInfo
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- CN110042188B CN110042188B CN201910358182.2A CN201910358182A CN110042188B CN 110042188 B CN110042188 B CN 110042188B CN 201910358182 A CN201910358182 A CN 201910358182A CN 110042188 B CN110042188 B CN 110042188B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/005—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using exothermic reaction compositions
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Abstract
The invention discloses a method for compensating the blowing end point temperature of a converter, belonging to the technical field of converter steelmaking. Aiming at the problems of molten steel peroxidation, alloy yield reduction, long period and the like caused by serious post-blowing after the current converter blowing end point is used for compensating the tapping temperature, the invention provides a converter blowing key temperature compensation method, which comprises the steps of measuring the temperature of the molten steel at the end point in the converter, and adding ferrosilicon alloy into the converter according to the addition of 0.07 kg/t-0.08 kg/t at each temperature rise of 1 ℃ if the temperature does not meet the tapping requirement; and oxygen blowing operation is carried out on the molten steel according to the heating rate of 1.1-1.2 ℃/s, and the oxygen blowing time is determined by the difference of the temperature rise of the molten steel; and after the oxygen blowing operation is finished, sampling and measuring the molten steel, and normally tapping after the requirements are met. The method utilizes the ferrosilicon as a heating agent, utilizes the chemical heat generated by the reaction of silicon and oxygen to increase the temperature of molten steel in the converter, and achieves the purposes of energy conservation and consumption reduction on the premise of ensuring that the converting end point temperature of the converter meets the target tapping temperature.
Description
Technical Field
The invention belongs to the technical field of converter steelmaking processes, and particularly relates to a converter blowing end point temperature compensation method.
Background
The heat balance in the converter steelmaking process means that the heat income item mainly comprises the balance relation among the physical heat of molten iron, the chemical heat and the heat deduction item mainly comprises the physical heat of molten steel, slag and furnace gas, the melting and decomposition heat of a coolant and the like, and the condition of the heat income item has important influence on the converter converting slagging process, the waste steel melting, the chemical reaction between slag and steel, the converting end point hit rate, the quality of molten steel material objects and the like. Under the influence of market situation and raw material price factors, some steel companies adopt a cooling system of 'fixing scrap and adjusting ore' for converters, and magnesium pellets are added into slagging materials to protect the furnace lining. The cooling system of 'regulating ore by fixed steel scrap' means that the addition of the selected steel scrap is calculated, the heat balance initial calculation is carried out, the surplus heat is obtained from the initial calculation result, and the addition of the ore is regulated in the blowing process of the converter so as to meet the heat balance requirement and realize the normal blowing of the converter. However, in the actual production process, due to the influence of molten iron components, particularly C, Si, Mn and temperature fluctuation, large size of heavy scrap, poor hot state of a steel ladle, mismatching of a converter and a casting machine node and other factors, the temperature of the blowing end point of the converter cannot meet the requirement of the target steel tapping temperature range, and after-blowing is carried out for compensating the steel tapping temperature at the blowing end point of the converter, the problems of serious molten steel peroxidation, reduced alloy yield, increased iron loss, prolonged smelting period, aggravated corrosion of a converter lining and the like are often caused. Therefore, the method for compensating the converter blowing end point temperature has strong practical significance for improving the quality of molten steel and the yield of alloy, shortening the smelting period and reducing the corrosion of the converter lining on the premise of ensuring that the converter blowing end point temperature meets the target tapping temperature range.
The method is characterized in that an ANS-OB refining process is adopted, namely, molten steel in a ladle is hoisted to an ANS-OB furnace for refining, the temperature is measured after the ladle bottom is blown with argon and stirred for 2-5 min, and the flow of the argon is 30-50 m3H; when the temperature of the molten steel is low, an oxygen lance is used for heating the molten steel, the ferrosilicon alloy is added into a steel ladle at the same time, the reaction heat release of oxygen and silicon is utilized, the temperature compensation is carried out on the low-temperature molten steel, and the oxygen blowing amount is increased by 8-10 m every time the temperature is raised by 1 DEG C3And h, increasing the addition of the ferrosilicon alloy by 0.05-0.06 kg/t. The disadvantages of the patent are that: although the method can effectively compensate the temperature of the low-temperature molten steel, the method needs to be carried out in an ANS-OB refining furnace, the equipment investment is large, and the popularization and application prospect is limited.
Also like Chinese patent application No. CN201810012432.2, published as 6/12/2018, the patent discloses a blowing process for improving secondary combustion efficiency of an RH refining furnace, belonging to the technical field of steel making. By adopting a top-blown secondary combustion oxygen lance blowing process in the RH refining furnace, CO gas generated by carbon-oxygen reaction is in more contact with oxygen, a secondary combustion area is enlarged, and the secondary combustion rate can be further improved. The main process is characterized in that for steel grade needing RH deep decarburization treatment, tapping [ C ] at the blowing end point of a converter]When the content is more than or equal to 0.05 percent, the forced decarburization operation of top blowing oxygen is executed, and the top blowing intensity0.13 to 0.17Nm3T, oxygen blowing and decarburization time is 4-6 min, the pressure of the vacuum chamber is gradually reduced from 101KPa to 0.067KPa, and after 18min of treatment, [ C ] can be achieved]The content is controlled below 0.0012 percent. The process can improve the secondary combustion rate by 20-30%, and compared with the traditional top lance oxygen blowing and decarburization process, the molten steel temperature is further compensated by about 4-6 ℃. The disadvantages of the patent are that: the range of the molten steel compensation temperature is small, the pressure of the vacuum chamber is not easy to control, and the process is complicated.
Disclosure of Invention
1. Problems to be solved
The invention provides a method for compensating the blowing end point temperature of a converter, aiming at the problems of molten steel peroxidation, alloy yield reduction, iron loss increase, smelting period extension and the like caused by serious post-blowing after the current converter blowing end point compensates the tapping temperature. The silicon-iron alloy is used as a heating agent, the chemical heat generated by the reaction of the heating element silicon and oxygen is utilized to raise the molten steel temperature of the converter molten pool, and on the premise of ensuring that the converting end point temperature of the converter meets the target tapping temperature, the purposes of saving energy and reducing consumption are achieved, the smelting period is effectively shortened, the consumption of steel materials is reduced, and the requirement of carbon-retaining tapping is met.
2. Technical scheme
In order to solve the above problems, the present invention adopts the following technical solutions.
A method for compensating the blowing end temperature of a converter comprises the following steps:
(1) measuring the carbon content, the oxygen content and the converter end point temperature of the molten steel end point by a converter sublance, directly tapping if the final tapping temperature is met, and carrying out end point temperature compensation on the molten steel by the following steps if the final tapping temperature is not met;
(2) after the temperature of molten steel was measured, the oxygen supply intensity was 3.2Nm3Adding ferrosilicon into the molten steel under the condition of min.t, wherein the adding amount of the ferrosilicon is 0.07 kg/t-0.08 kg/t according to the temperature rise of 1 ℃;
(3) carrying out oxygen blowing operation on the molten steel according to the heating rate of 1.1-1.2 ℃/s, wherein the oxygen blowing time is determined by the difference of the temperature rise of the molten steel;
(4) and after the oxygen blowing operation is finished, sampling and measuring the temperature of the molten steel, and tapping after the tapping temperature of the molten steel is reached. Compared with the traditional over-drawing temperature process, the method for compensating the blowing end point temperature of the converter can reduce the smelting period by 20-30 s, reduce the content of O in steel by 400-500 ppm, improve the alloy yield by 10-15 percent, reduce the consumption of steel and iron materials by 15-20 kg/t and greatly save the cost for enterprises.
Further, the ferrosilicon alloy in the step (2) is ferrosilicon alloy containing 72.5% of silicon.
Furthermore, the ferrosilicon is added into the converter through a high-level bunker.
Furthermore, the overhead bin comprises an alloy bin, the alloy bin is connected with the flow guide pipeline through a valve, and a resistance wire mesh is arranged in the alloy bin. When needing reinforced, open the valve, the ferrosilicon alloy in the alloy feed bin enters into the converter through the water conservancy diversion pipeline, has realized that the molten steel is at smelting in-process online adjustment ferrosilicon alloy, and whole charging process need not cut off the power supply etc. and operate for the ferrosilicon alloy adds the simple and convenient swift of operation of converter, improves work efficiency.
Further, the alloy bin is funnel-shaped. The ferrosilicon alloy is led into the converter more smoothly, the blockage is not easy to occur, and the smelting period is shortened.
Furthermore, after the oxygen blowing operation in the step (4) is finished, the converter is shaken to the slag pouring surface, the angle between the converter and the slag pouring surface is between 80 and 85 degrees, and then sampling measurement is carried out. The converter and the deslagging surface are arranged at a certain angle, so that the molten steel reaction in the converter tends to be stable, and the finally measured molten steel data has higher accuracy.
Furthermore, the converter sublance comprises a sublance rod and an induction probe assembly arranged in the sublance rod, wherein the induction probe assembly comprises a probe sleeve, a sealing sleeve and a conduit, the conduit and the sealing sleeve are arranged in the sublance rod, the end of the conduit is connected with one end of the sealing sleeve, and one end of the conduit passes through an insertion hole at the end of the sublance rod and is connected with the other end of the sealing sleeve. The probe sleeve and the sublance rod adopt a splicing structure, so that the replacement of the induction probe becomes convenient and rapid, and the working efficiency of the converter sublance is improved;
furthermore, sealing gaskets are arranged on the pipe body of the probe sleeve penetrating through the plug hole and the pipe body of the probe sleeve connected with the sealing sleeve, and a spring is arranged between the two sealing gaskets. The spring can further increase the sealing performance of the sealing gasket, so that the data of the converter sublance measured by the converter molten steel in the converter is more accurate, the accuracy of the measured data is improved, and the reliability is higher.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) the invention adopts the ferrosilicon alloy with higher heating value as the heating agent, the silicon oxidation speed of the heating element is high, the heat effect value is high, the molten steel temperature of the converter molten pool is rapidly improved, the carbon-retaining tapping can be realized, the smelting period is favorably shortened, the converter condition is stable and smooth, and the silicon in the ferrosilicon heating agent reacts with the oxygen to generate SiO2The slag enters the furnace slag, the composition of the crude steelmaking water is hardly influenced, and the quality of molten steel material objects is improved; compared with the traditional over-drawing temperature process, the method for compensating the blowing end point temperature of the converter can reduce the smelting period by 20-30 s and reduce the content of [ O ] in steel]The content can be reduced by 400ppm to 500ppm, the alloy yield can be improved by 10 percent to 15 percent, the consumption of steel materials can be reduced by 15kg/t to 20kg/t, and the cost is greatly saved for enterprises;
(2) the method for improving the end point temperature of the molten steel is carried out in the converter, the investment of other equipment is not required to be increased, and the production cost is saved; the ferrosilicon is added into the converter by the over-high bin, the high bin comprises an alloy bin, the alloy bin is connected with the diversion pipeline by a valve, and a resistance wire mesh is arranged in the alloy bin, so that the ferrosilicon is adjusted on line in the smelting process of molten steel, and the whole feeding process does not need to be powered off and other operations, so that the ferrosilicon is added into the converter simply, conveniently and quickly, and the working efficiency is improved; the alloy bin is funnel-shaped, so that the ferrosilicon alloy is introduced into the converter more smoothly and is not easy to block;
(3) after the oxygen blowing operation is finished, the converter is shaken to the deslagging surface, so that the converter and the deslagging surface are between 80 and 85 degrees, sampling measurement is performed, the molten steel in the converter is reacted stably, the error of a subsequent measurement result is reduced, and the final measurement result has accuracy and reliability;
(4) according to the invention, the converter sublance is used for detecting molten steel, and the probe sleeve and the sublance rod in the converter sublance adopt a plug-in structure, so that the replacement of an induction probe is convenient and rapid; the sealing gaskets are used for rapidly sealing between the probe sleeve and the sealing sleeve and between the probe sleeve and the wire inserting hole, the sealing performance of the sealing gaskets can be improved by the springs, the sealing performance is good, and the accuracy is high when the molten steel in the converter is measured.
Drawings
FIG. 1 is a flow chart of the present invention.
Detailed Description
The invention is further described with reference to specific embodiments and the accompanying drawings.
Example 1
As shown in fig. 1, a method for compensating the temperature of the blowing endpoint of a converter comprises the following steps:
(1) measuring the carbon content, the oxygen content and the converter end point temperature of the molten steel end point by a converter sublance, directly tapping if the final tapping temperature is met, and carrying out end point temperature compensation on the molten steel by the following steps if the final tapping temperature is not met; and finally, the tapping temperature of the molten steel is set according to different steel types and requirements and specific steel types.
(2) After the temperature of molten steel was measured, the oxygen supply intensity was 3.2Nm3Adding ferrosilicon into the molten steel under the condition of min.t, preferably, the ferrosilicon is ferrosilicon with 72.5 percent of silicon content; the adding amount of the ferrosilicon alloy is 0.07kg/t to 0.08kg/t when the temperature is raised to 1 ℃; the ferrosilicon with higher heating value is adopted as the heating agent, the silicon oxidation speed of the heating element silicon is high, the heat effect value is high, the molten steel temperature of the converter molten pool is rapidly improved, carbon-retaining tapping can be realized, the smelting period is favorably shortened, and the converter is favorably usedThe furnace condition is stable and smooth, and the silicon in the ferrosilicon exothermic agent reacts with oxygen to generate SiO2The slag enters the furnace slag, the composition of the crude steelmaking water is hardly influenced, and the quality of molten steel material objects is improved;
(3) carrying out oxygen blowing operation on the molten steel according to the heating rate of 1.1-1.2 ℃/s, wherein the oxygen blowing time is determined by the difference of the temperature rise of the molten steel; the smelting period is greatly reduced, and the cost is saved for enterprises;
(4) and after the oxygen blowing operation is finished, sampling and measuring the temperature of the molten steel, and tapping after the tapping temperature of the molten steel is reached. Preferably, after the oxygen blowing operation is finished, the converter is shaken to the slag pouring surface, the angle between the converter and the slag pouring surface is 80-85 degrees, then sampling measurement is carried out, the molten steel in the converter reacts stably, and the error of a subsequent measurement result is reduced, so that the final measurement result has accuracy and reliability.
The invention adopts the silica heating process, aims at the condition that the required heating amplitude is more than 30 degrees, and does not have great influence on the quality of the molten steel discharged from the furnace if the final tapping temperature of the molten steel is less than 30 degrees from the target temperature, so that the ferrosilicon alloy does not need to be heated for heating; when the final tapping temperature of the molten steel is more than 30 ℃ lower than the target temperature, the excessive drawing is possibly caused to cause high oxygen level of the molten steel, and the quality of the material object and the yield of the alloy are influenced; the invention utilizes the characteristics of high silicon oxidation speed and high thermal effect value of the heating element to quickly raise the molten steel temperature of the converter molten pool, and SiO generated by the reaction2The slag enters the furnace slag and almost has no influence on the components of the molten steel; in addition, the method is carried out in the converter, other equipment investment is not needed, and the application prospect is worthy of popularization; the invention provides a method for compensating the blowing end point temperature of a converter, which improves the quality of molten steel and the yield of alloy on the premise of ensuring that the blowing end point temperature of the converter meets the target tapping temperature, shortens the smelting period and reduces the corrosion of the converter lining. Meanwhile, the method has the characteristics of quick temperature rise, low cost, safety and environmental protection; compared with the traditional over-drawing temperature process, the method for compensating the blowing end point temperature of the converter can reduce the smelting period by 20-30 s and reduce the content of [ O ] in steel]The content can be reduced by 400ppm to 500ppm, the alloy yield can be improved by 10 percent to 15 percent,the consumption of steel materials can be reduced by 15 kg/t-20 kg/t, and the cost is greatly saved for enterprises.
Example 2
Basically as in example 1, preferably, the ferrosilicon is added into the converter through a high-level bunker, the high-level bunker includes an alloy bunker, the alloy bunker is connected with a diversion pipeline through a valve, and a resistance wire mesh is arranged in the alloy bunker; when the device is used, the resistance wire mesh is electrified and burnt to be in a red hot state in advance when feeding is needed, the woven bagged ferrosilicon alloy is hoisted and falls onto the resistance wire mesh, the bottom of the woven bag is burnt, the ferrosilicon alloy falls into an alloy bin, when the ferrosilicon alloy needs to be added, a valve is opened, and the ferrosilicon alloy flows into a converter through a flow guide pipeline, so that the ferrosilicon alloy is adjusted on line in the smelting process of molten steel, the operations such as power failure and the like are not needed in the whole feeding process, the ferrosilicon alloy is added into the converter simply, conveniently and quickly, and the working efficiency is improved; the alloy bin is funnel-shaped, so that the ferrosilicon alloy is introduced into the converter more smoothly and is not easy to block;
the converter sublance comprises a sublance rod and an induction probe assembly arranged in the sublance rod, wherein the induction probe assembly comprises a probe sleeve, a sealing sleeve and a conduit, the conduit and the sealing sleeve are arranged in the sublance rod, the end of the conduit is connected with one end of the sealing sleeve, and one end of the conduit passes through an insertion hole at the end of the sublance rod and is connected with the other end of the sealing sleeve, so that the induction probe is convenient and quick to replace; the probe sleeve penetrates through the pipe body of the plug hole, the pipe body of the probe sleeve connected with the sealing sleeve is provided with the sealing gaskets, the spring is arranged between the two sealing gaskets, the sealing performance of the sealing gaskets can be improved through the spring, the sealing performance is good, and the accuracy is high when the molten steel in the converter is measured.
Example 3
When the converter blows to the end point, because the residual heating elements in the steel mainly comprise C, Mn content which is oxidized to a lower level, the silicon-iron alloy with higher heating value and containing 72.5 percent of silicon is added into the converter as a heating agent, the chemical heat generated by the reaction of the heating elements of silicon and oxygen is utilized to increase the molten steel temperature of the converter molten pool, and the silicon and the oxygen in the silicon-iron heating agentReaction of oxygen to form SiO2The slag enters the furnace slag, almost has no influence on the components of the crude steelmaking water, and is beneficial to improving the quality of molten steel objects. Through statistics and analysis of a large amount of experimental data, the invention determines the corresponding relation between the carbon content of different end points and the oxygen level of molten steel, the excess index when the ferrosilicon exothermic agent reaches the highest heating efficiency and the oxygen supply intensity when the ferrosilicon exothermic agent reaches the fastest heating rate, and finally determines the relation among the addition amount of the ferrosilicon alloy exothermic agent, the oxygen supply intensity and the heating rate, and the technical scheme is as follows:
the method is based on the calculation that the average steel tapping amount of a converter with the nominal volume of 70t is 68t, the actually measured content of a molten steel terminal point [ C ] is 0.102%, the content of molten steel [ O ] is 266.58ppm, the terminal temperature of the converter is 1630 ℃, the temperature rise amplitude is 50 ℃, and the heating efficiency eta and the oxygen utilization rate of the ferrosilicon alloy are both 100%.
1) Determination of the addition of the ferrosilicon alloy exothermic agent
m(SiFe)＝ΔT×Cp molten steel×mMolten steel/qSilicon iron
＝50×0.878×68×1000/19743.2/72.5％/85％
＝245.36kg
In the formula: delta T is the temperature rise amplitude; cp molten steelThe specific heat capacity of the molten steel; m isMolten steelThe amount of molten steel is; q. q.sSilicon ironThe heat effect of the ferrosilicon alloy is adopted; the yield of silicon in the ferrosilicon alloy is 85%, because the added ferrosilicon alloy cannot be recovered by 100%, a certain amount of silicon is lost.
2) Oxygen supply determination
a. Determination of oxygen content in molten steel
m[O]Molten steel＝68×1000×266.58×10-6＝18.12kg
b. Oxygen supply determination
According to the reaction formula O of heating element silicon and oxygen2+[Si]＝(SiO2) And calculating the oxygen supply amount.
3) Oxygen supply time determination
At an oxygen supply intensity q of 3.2Nm3V (min. t), the oxygen blowing time t is determined.
t＝Q/q＝108.28/68/3.2≈0.50min＝30s
Considering the comprehensive factors of the heat absorption of ferrosilicon added into the converter for melting, the heat loss of the converter, the additional supplement of metallurgical lime for melting and heat absorption for ensuring the alkalinity of final slag and preventing the rephosphorization, the actual oxygen utilization rate and the like, the oxygen supply intensity is 3.2Nm3The oxygen blowing time is widened to 55-60 s under the condition of min.t; based on the analysis and through the statistics of a large amount of experimental data, adopt the intensification technology of silicothermic method compensation converter converting terminal point temperature, the relation between ferrosilicon alloy heating element addition, oxygen blowing intensity and rate of rise is: at an oxygen supply intensity of 3.2Nm3Under the condition of min.t, the adding amount of the ferrosilicon alloy is increased by 0.07-0.08 kg/t at the temperature of 1 ℃ per liter, and the heating rate is 1.1-1.2 ℃/s. In the actual operation process, the difference value between the molten steel temperature and the target molten steel tapping temperature is calculated according to the relation, so that the quantity of the ferrosilicon alloy and the oxygen blowing time are calculated, the quality of molten steel and the yield of the alloy are improved, the smelting period is shortened, and the corrosion of a converter lining is reduced on the premise of ensuring that the converter blowing end point temperature meets the target molten steel tapping temperature; meanwhile, the method has the characteristics of quick temperature rise, low cost, safety and environmental protection.
Taking low alloy steel Q345B as an example, the average steel tapping amount of a converter with a nominal volume of 70t is 68t, and the steel tapping temperature range required by the steel type process is 1655-1675 ℃. Actually measured molten steel end point [ C ]]0.113% in molten steel [ O ]]The content is 262.43ppm, the end point temperature of the converter is 1620 ℃, the end point temperature can not reach the target tapping temperature requirement, and the end point temperature of the molten steel needs to be compensated. The middle limit value of the temperature range required by the steel grade process of 1665 ℃ is taken as a heating target value, namely, the heating amplitude is 45 ℃. According to the method for compensating the temperature at the end point of converter blowing of the present invention, the oxygen supply intensity is 3.2Nm3And/(min.t) under the condition that the temperature per liter is 1 ℃, the adding amount of the ferrosilicon is increased by 0.07-0.08 kg/t, the heating rate is 1.1-1.2 ℃/s, and the adding amount of the ferrosilicon and the oxygen supply time are respectively and conveniently calculated.
1) Calculating the addition of ferrosilicon
m(SiFe)＝0.075kg/t×68t×45＝229.5kg
2) Determination of oxygen supply time
t＝1.15℃/s×45℃＝51.75s
3) Adding ferrosilicon alloy
230kg of ferrosilicon alloy is added into the converter through a high-level bunker.
4) Oxygen blowing operation
Setting oxygen supply pressure 750kpa, oxygen lance position 1200mm and oxygen flow 13500m3H is used as the reference value. Turning on a button for blowing off the oxygen lance, automatically turning off the oxygen lance to 1200mm, and starting oxygen; lowering the lance to 1000mm manually, and blowing oxygen for 52 s; and turning on a button for lifting the oxygen lance to a waiting point, automatically lifting the oxygen lance to 6500mm, closing oxygen and stopping oxygen supply.
5) Temperature measurement sampling
After oxygen blowing is finished, the converter is shaken to a deslagging surface to a 82-degree temperature measurement sampling position, temperature measurement sampling is carried out after reaction in the converter is stable, the actually measured end point [ C ] content of the molten steel is 0.082%, the content of the molten steel [ O ] is 321.32ppm, the temperature of the molten steel is 1668 ℃, the target tapping temperature is 1655-1675 ℃, and carbon-retaining tapping is realized.
Example 4
Basically the same as example 3, taking killed steel Q235B as an example, a converter with a nominal volume of 70t has an average tapping amount of 68t, and the tapping temperature range required by the steel type process is 1635-1655 ℃. Actually measured molten steel end point [ C ]]0.108% in molten steel [ O ]]The content is 247.32ppm, the end point temperature of the converter is 1615 ℃, the end point temperature does not meet the requirement of the target tapping temperature, and the end point temperature of the molten steel needs to be compensated. The middle limit value of the temperature range required by the steel grade process is 1645 ℃ as a heating target value, namely the heating range is 30 ℃. According to the method for compensating the temperature at the end point of converter blowing of the present invention, the oxygen supply intensity is 3.2Nm3And/(min.t) under the condition that the temperature per liter is 1 ℃, the adding amount of the ferrosilicon is increased by 0.07-0.08 kg/t, the heating rate is 1.1-1.2 ℃/s, and the adding amount of the ferrosilicon and the oxygen supply time are respectively and conveniently calculated.
1) Calculating the addition of ferrosilicon
m(SiFe)＝0.075kg/t×68t×30＝153kg
2) Determination of oxygen supply time
t＝1.15℃/s×30℃＝34.5s
3) Adding ferrosilicon alloy
155kg of ferrosilicon alloy was added to the converter through a high-level bunker.
4) Oxygen blowing operation
Setting oxygen supply pressure 750kpa, oxygen lance position 1200mm and oxygen flow 13500m3H is used as the reference value. Turning on a button for blowing off the oxygen lance, automatically turning off the oxygen lance to 1200mm, and starting oxygen; lowering the lance to 1000mm manually, and blowing oxygen for 35 s; and turning on a button for lifting the oxygen lance to a waiting point, automatically lifting the oxygen lance to 6500mm, closing oxygen and stopping oxygen supply.
5) Temperature measurement sampling
After oxygen blowing is finished, the converter is shaken to the slag dumping surface to a temperature measurement sampling position of 83 degrees, temperature measurement sampling is carried out after the reaction in the converter is stable, the actually measured content of the molten steel terminal point [ C ] is 0.076%, the content of the molten steel [ O ] is 313.43ppm, the temperature of the molten steel is 1648 ℃, the target tapping temperature is 1635-1655 ℃, and carbon-retaining tapping is realized.
Example 5
Basically, the steel is the same as the example 3, taking low alloy steel HRB400B as an example, a converter with a nominal volume of 70t has an average steel tapping amount of 68t, and the steel tapping temperature range required by the steel type process is 1640-1660 ℃. Actually measured molten steel end point [ C ]]0.108% in molten steel [ O ]]The content is 247.32ppm, the end point temperature of the converter is 1610 ℃, the end point temperature can not reach the target tapping temperature requirement, and the end point temperature of the molten steel needs to be compensated. The middle limit value 1650 ℃ of the process requirement temperature range of the steel grade is taken as a temperature rise target value, namely, the temperature rise amplitude is 40 ℃. According to the method for compensating the temperature at the end point of converter blowing of the present invention, the oxygen supply intensity is 3.2Nm3And/(min.t) under the condition that the temperature per liter is 1 ℃, the adding amount of the ferrosilicon is increased by 0.07-0.08 kg/t, the heating rate is 1.1-1.2 ℃/s, and the adding amount of the ferrosilicon and the oxygen supply time are respectively and conveniently calculated.
1) Calculating the addition of ferrosilicon
m(SiFe)＝0.075kg/t×68t×40＝204kg
2) Determination of oxygen supply time
t＝1.15℃/s×40℃＝46s
3) Adding ferrosilicon alloy
204kg of ferrosilicon alloy is added into the converter through a high-level bunker.
4) Oxygen blowing operation
Setting oxygen supply pressure 750kpa, oxygen lance position 1200mm and oxygen flow 13500m3H is used as the reference value. Turning on a button for blowing off the oxygen lance, automatically turning off the oxygen lance to 1200mm, and starting oxygen; lowering the lance to 1000mm manually, and blowing oxygen for 46 s; and turning on a button for lifting the oxygen lance to a waiting point, automatically lifting the oxygen lance to 6500mm, closing oxygen and stopping oxygen supply.
5) Temperature measurement sampling
After oxygen blowing is finished, the converter is shaken to the slag dumping surface to a temperature measurement sampling position of 84 degrees, temperature measurement sampling is carried out after the reaction in the converter is stable, the actually measured molten steel terminal point [ C ] content is 0.068%, the molten steel [ O ] content is 345.16ppm, the molten steel temperature is 1657 ℃, the target tapping temperature is reached to 1640-1660 ℃, and carbon-preserving tapping is realized.
The examples described herein are merely illustrative of the preferred embodiments of the present invention and do not limit the spirit and scope of the present invention, and various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the design concept of the present invention shall fall within the protection scope of the present invention.
Claims (6)
1. A method for compensating the blowing end point temperature of a converter is characterized by comprising the following steps: the method comprises the following steps:
(1) measuring the carbon content, the oxygen content and the converter end point temperature of the molten steel end point by a converter sublance, directly tapping if the final tapping temperature is met, and carrying out end point temperature compensation on the molten steel by the following steps if the final tapping temperature is not met;
(2) after the temperature of molten steel was measured, the oxygen supply intensity was 3.2Nm3Adding ferrosilicon into the molten steel under the condition of min.t, wherein the adding amount of the ferrosilicon is 0.07 kg/t-0.08 kg/t according to the temperature rise of 1 ℃; the ferrosilicon alloy is ferrosilicon alloy containing 72.5 percent of silicon;
(3) carrying out oxygen blowing operation on the molten steel according to the heating rate of 1.1-1.2 ℃/s, wherein the oxygen blowing time is determined by the difference of the temperature rise of the molten steel;
(4) after the oxygen blowing operation is finished, sampling and measuring the temperature of the molten steel, and tapping after the tapping temperature of the molten steel is reached; after the medium oxygen blowing operation is finished, the converter is shaken to the slag pouring surface, the angle between the converter and the slag pouring surface is between 80 and 85 degrees, and then sampling measurement is carried out.
2. The method of claim 1, wherein the method comprises the steps of: the ferrosilicon alloy is added into the converter through a high-level bunker.
3. The method of claim 2, wherein the method comprises the steps of: the high-level stock bin comprises an alloy stock bin, the alloy stock bin is connected with the flow guide pipeline through a valve, and a resistance wire mesh is arranged in the alloy stock bin.
4. The method of claim 3, wherein the method comprises the steps of: the alloy bin is funnel-shaped.
5. The method of claim 1, wherein the method comprises the steps of: the converter sublance comprises a sublance rod and an induction probe assembly arranged in the sublance rod, wherein the induction probe assembly comprises a probe sleeve, a sealing sleeve and a conduit, the conduit and the sealing sleeve are arranged in the sublance rod, the end of the conduit is connected with one end of the sealing sleeve, and one end of the conduit penetrates through an insertion hole at the end of the sublance rod and is connected with the other end of the sealing sleeve.
6. The method of claim 5, wherein the method comprises the steps of: the probe sleeve penetrates through the pipe body of the plug hole, sealing gaskets are arranged on the pipe body of the probe sleeve connected with the sealing sleeve, and springs are arranged between the two sealing gaskets.
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| MX2022008553A (en) * | 2020-01-09 | 2022-10-21 | Vesuvius Refratarios Ltda | Lance for use in metal production and casting installations. |
| CN115041642B (en) * | 2022-05-23 | 2023-06-27 | 宝武集团鄂城钢铁有限公司 | Tapping method of converter |
| CN115747404A (en) * | 2022-11-07 | 2023-03-07 | 河钢乐亭钢铁有限公司 | Cold material adding method in converter process |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH0641626A (en) * | 1992-07-24 | 1994-02-15 | Kawasaki Steel Corp | Oxygen blowing control method of converter |
| CN101845531B (en) * | 2010-05-07 | 2011-11-02 | 河北省首钢迁安钢铁有限责任公司 | Converter smelting endpoint molten steel carbon and temperature control system and method thereof |
| CN102206727A (en) * | 2011-05-31 | 2011-10-05 | 湖南镭目科技有限公司 | Converter steelmaking endpoint determination method and system, control method and control system |
| CN102719608A (en) * | 2012-03-29 | 2012-10-10 | 鞍钢股份有限公司 | Steel ladle inner molten steel temperature compensation method |
| KR20140017141A (en) * | 2012-07-31 | 2014-02-11 | 현대제철 주식회사 | Method for controlling temperature of molten steel in converter |
| CN204918712U (en) * | 2015-09-17 | 2015-12-30 | 通裕重工股份有限公司 | Online feeding device of high -order feed bin of refining furnace |
| CN205603624U (en) * | 2016-05-05 | 2016-09-28 | 天水岷山机械有限责任公司 | Converter detects sublance |
| CN108676955B (en) * | 2018-05-02 | 2019-07-12 | 中南大学 | A kind of BOF Steelmaking Endpoint carbon content and temprature control method |
| CN110735015A (en) * | 2019-09-26 | 2020-01-31 | 武汉华枫传感技术股份有限公司 | Automatic measuring method and device for converter steelmaking sublance |
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