CN116770018A - Method for controlling molten steel temperature by LF bottom blowing argon - Google Patents
Method for controlling molten steel temperature by LF bottom blowing argon Download PDFInfo
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- 238000007664 blowing Methods 0.000 title claims abstract description 360
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 248
- 239000010959 steel Substances 0.000 title claims abstract description 248
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 title claims abstract description 110
- 238000000034 method Methods 0.000 title claims abstract description 107
- 229910052786 argon Inorganic materials 0.000 title claims abstract description 55
- 239000000463 material Substances 0.000 claims abstract description 84
- 238000004364 calculation method Methods 0.000 claims abstract description 37
- 230000008569 process Effects 0.000 claims abstract description 33
- 230000008859 change Effects 0.000 claims abstract description 24
- 239000000523 sample Substances 0.000 claims abstract description 18
- 238000010438 heat treatment Methods 0.000 claims description 21
- 238000009529 body temperature measurement Methods 0.000 claims description 16
- 239000000956 alloy Substances 0.000 claims description 14
- 229910045601 alloy Inorganic materials 0.000 claims description 14
- 230000000977 initiatory effect Effects 0.000 claims description 12
- 239000007789 gas Substances 0.000 claims description 11
- 238000007599 discharging Methods 0.000 claims description 9
- 238000009792 diffusion process Methods 0.000 claims description 8
- 230000007423 decrease Effects 0.000 claims description 4
- 238000004886 process control Methods 0.000 claims description 4
- 238000012545 processing Methods 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 21
- 230000005611 electricity Effects 0.000 abstract description 7
- 230000000694 effects Effects 0.000 abstract description 6
- 230000001276 controlling effect Effects 0.000 description 24
- 238000007670 refining Methods 0.000 description 10
- 239000002893 slag Substances 0.000 description 6
- 230000017525 heat dissipation Effects 0.000 description 3
- 238000009628 steelmaking Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 238000006477 desulfuration reaction Methods 0.000 description 2
- 230000023556 desulfurization Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000010310 metallurgical process Methods 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012821 model calculation Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000033764 rhythmic process Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- 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
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
-
- 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
- C21C2300/00—Process aspects
- C21C2300/06—Modeling of the process, e.g. for control purposes; CII
Abstract
The invention relates to a method for controlling the temperature of molten steel by LF bottom blowing argon, which comprises the following steps: step 1: acquiring data; step 2: measuring the initial temperature of molten steel by using a temperature measuring probe; step 3: calculating the temperature change of the input material to molten steel; step 4: calculating the time required by feeding; step 5: calculating the time required for feeding the wire; step 6: calculating the natural temperature drop of molten steel; step 7: calculating the temperature drop value of bottom blowing to molten steel under the condition of controlling the standard bottom blowing flow; step 8: calculating a set value of the strong bottom blowing flow; step 9: and (3) issuing a bottom blowing flow value to L1, and controlling the bottom blowing flow. The invention uses the calculation method of LF bottom blowing to control the molten steel temperature, accurately calculates the stable flow of LF bottom blowing in the molten steel bottom blowing process, ensures the uniformity of the molten steel temperature, and accurately controls the molten steel temperature to be equal to the target temperature at the end of LF treatment, thereby reducing the consumption of bottom blowing argon and electricity consumption in the LF production process, and has remarkable effect.
Description
Technical Field
The invention relates to a method, in particular to a method for controlling the temperature of molten steel by LF bottom blowing argon, belonging to the technical field of production and control of metallurgical processes.
Background
The LF refining furnace is equipment for refining molten steel, and has the main functions of molten steel desulfurization, adjustment of various elements in molten steel and molten steel temperature control, so that the molten steel meets the standard requirements of the steel grade. In the whole LF production process, LF bottom blowing argon is started to be blown from the start-in ladle to the bottom blowing pipe, and the bottom blowing argon is always performed during the period from the start-up ladle to the pull-out of the bottom blowing pipe to leave the station; after entering a station, different bottom blowing flows can be regulated in different treatment processes to meet the requirements of each treatment process, for example, weak bottom blowing is required when LF is used for feeding and wire feeding, and strong bottom blowing is required at other moments, if the temperature is too high, the flow of the strong bottom blowing can be increased to enable the temperature of molten steel to be quickly reduced, and the temperature of molten steel is equal to the target outlet temperature when the molten steel leaves the station, so that the temperature cannot be too high or too low; in the actual treatment process, operators need to judge the temperature change condition of the molten steel through temperature measurement so as to adjust the bottom blowing flow, and the temperature of the molten steel is accurately controlled under the condition of ensuring the bottom blowing flow requirements of all the treatment processes. However, in the actual operation process, it is difficult to accurately and stably control the bottom blowing flow, and factors influencing the temperature of molten steel are very large, so that the cost of argon and electricity consumption is increased.
At present, most steel plants adopt a method of manually adjusting bottom blowing flow to control the temperature of molten steel, and all the steel plants often have influence on the production rhythm and the quality of molten steel; in order to save the consumption of bottom blowing argon and electricity consumption and improve the quality of molten steel, the bottom blowing flow needs to be automatically adjusted, and therefore, there is room for improvement in this respect.
In recent years, some steel plants in China also carry out some research work on controlling the temperature of bottom blowing flow, and the following four patents relate to the research field:
bottom argon blowing LF furnace, auxiliary argon blowing device and auxiliary argon blowing method thereof, and patent numbers are as follows: CN201710762010.2. The invention relates to an auxiliary argon blowing device based on LF furnace bottom argon blowing, an argon blowing method of the auxiliary argon blowing device and a bottom argon blowing LF furnace provided with the auxiliary argon blowing device. The auxiliary argon blowing device provided by the invention can timely perform auxiliary argon blowing in the furnace when the argon blowing at the bottom of the LF furnace is insufficient or fails, ensures smooth production, avoids the influence of excessively increasing the flow of the bottom argon blowing on the service life of the steel ladle, and can avoid ladle pouring operation or degradation treatment of molten steel.
A system and a method for controlling the temperature of molten steel in an LF refining process on line, and the patent number is: CN201310306019.4. A system and a method for controlling the molten steel temperature in an LF refining process on line belong to the technical field of production and control of metallurgical processes, and the system comprises: the device comprises an information acquisition module, a heating judging module, an electrode heating and temperature rising module, a steel ladle lining heat dissipation module, an alloy adding judging module, an alloy heat effect module, a slag adding judging module, a slag heat effect module, an argon blowing slag layer judging module, a molten steel radiation heat dissipation module, an argon heat absorption module, a slag layer heat dissipation module, a temperature calculation module, a temperature correction judging module, a temperature correction module, a temperature forecasting module and a temperature control module. The method comprises the following steps: the on-line control of the molten steel temperature in the LF refining process is to obtain the real-time temperature of molten steel after calculating the molten steel temperature variation caused by the heating up and cooling down processes in the LF refining process, and control the heating up process by adjusting the heating time, so that the real-time temperature of molten steel reaches the target temperature of molten steel and is controlled within the allowable control precision range of the LF refining site.
A method for continuously detecting the temperature of molten steel in the production process of an LF refining furnace, which comprises the following steps: CN201310090990.8. The invention relates to a method for continuously detecting the temperature of molten steel in the production process of an LF refining furnace, belonging to the technical field of metallurgical control. The technical proposal is as follows: before the computer system is used, firstly, a temperature measuring gun with a disposable temperature measuring head inserted in site is utilized to detect the temperature of molten steel, and the detected result is transmitted into the computer system; the temperature measurement is taken as a starting point of continuous temperature measurement, and the data of power supply, material feeding, cored wire feeding and bottom blowing information are combined and periodically transmitted into a computer system for dynamic calculation, and the system can finally accurately output the temperature of the molten steel at the current moment according to the influence of the information on the temperature of the molten steel. The invention has the advantages and effects that: on the premise of meeting the field requirement on the detection precision of the molten steel temperature, the continuous temperature measurement in the production process is realized, the detection cost is low, the temperature of molten steel at any moment is finally obtained, the calculation result is continuously displayed on a user interface, the production of LF refining operators is guided, and the molten steel quality is improved.
A bottom blowing mode automatic control method of a combined blown converter comprises the following steps: CN201610741393.0. The invention discloses a bottom blowing mode control method of a combined blown converter, which aims at controlling bottom blowing operations of an iron charging stage, a blowing stage, a slag pouring stage, a point blowing stage, a temperature measuring and sampling stage, a waiting stage, a tapping stage and a slag splashing stage in the combined blown converter, adjusting bottom blowing source types, air supply intensity and blowing time in the bottom blowing operations of each stage according to different steel types and end carbon content ranges to obtain corresponding bottom blowing modes, setting control buttons corresponding to the different bottom blowing modes on an operation interface of a control system, and selecting the bottom blowing modes by clicking the control buttons. According to the invention, through increasing the automatic design and application of the air supply pressure modes in each stage and each reaction period in the converting process, the dynamic conditions of the existing converter molten pool are effectively improved, the uniformity of the components of the converter end-point molten pool and the stability of the temperature are improved, the number of post-blowing furnaces is reduced, the blowing loss is reduced, the magnesium material addition amount for protecting the furnace is reduced, and the refractory cost is saved.
The control methods described in the above 4 patents relate to LF molten steel temperature control and bottom blowing control methods, no mention is made of bottom blowing argon gas control molten steel temperature described in the present patent, and the present invention relates to a method for bottom blowing argon gas control molten steel temperature, which is different from the control routes and purposes of the above four patents.
Disclosure of Invention
The invention provides a method for controlling the temperature of molten steel by LF bottom blowing argon, which aims at the problems in the prior art, and the technical scheme is that the speed of the temperature decrease of the molten steel is controlled by adjusting the flow of the bottom blowing argon in the whole LF bottom blowing treatment process, so that the actual outlet temperature of the molten steel is ensured to be equal to the target outlet temperature; the invention mainly uses a calculation method for controlling the temperature of molten steel by LF bottom blowing argon, accurately calculates the steady flow set value of LF bottom blowing argon in the LF treatment process of molten steel, ensures the uniformity of the temperature of molten steel, and accurately controls the temperature of molten steel to be equal to the target temperature at the end of LF treatment, thereby reducing the consumption of bottom blowing argon and power consumption in the LF production process.
In order to achieve the above purpose, the technical scheme of the invention is as follows, a method for controlling molten steel temperature by LF bottom blowing argon, the method comprises the following steps:
step 1: the method comprises the steps of obtaining data, and obtaining the weight of molten steel in the current treatment heat, the initial temperature of the molten steel, the target temperature of the molten steel, the planned LF treatment ending time and other data through a secondary process control system. Obtaining the type and weight of materials (including the type and length of wire feeding) to be input into the furnace molten steel from the LF alloy model, wherein the data are calculated by the alloy model at the beginning of the furnace number;
step 2: the initial temperature of the molten steel was measured using a temperature probe. After the furnace enters the station, the temperature of the molten steel is measured by a temperature measuring probe, thereby obtaining the initial temperature of the molten steel (marked as T Initial initiation )；
Step 3: and calculating the temperature change of the input material to the molten steel. The calculation result of the alloy model is obtained in the step 1, and comprises the type and weight of the materials required to be input (the weight of each material is recorded as W i ) The step is mainly to calculate the change of the temperature of the molten steel after the materials are put into the molten steel (the temperature drop after each material is put into is recorded as: t (T) i ) Wherein, the temperature change coefficient of each material is:the density of each yarn was: alpha i 。
The calculation method for converting the wire feeding length into weight comprises the following steps:
W i ＝L i ×α i ………(1)
the method for calculating the temperature change of molten steel caused by feeding each material comprises the following steps:
the method for calculating the temperature change of molten steel caused by feeding all materials comprises the following steps:
T material ＝T 1 +T 2 +...+T i ………(3)
Wherein:
T material : after all materials are put into the furnace, the temperature of molten steel is changed (unit is shown in DEG C); if the temperature of the molten steel is negative, the temperature of the molten steel is reduced, and if the temperature of the molten steel is positive, the temperature of the molten steel is increased;
step 4: the time required for feeding was calculated. I.e. the time interval from the start of feeding to the completion of feeding, the length of time being determined by the total weight of all the materials to be fed (denoted as W Total weight of ) And the blanking speed of the feeding and collecting hopper (recorded as: v (V) Discharging speed ) Determining;
the method for calculating the feeding time of all the materials comprises the following steps:
S time of feeding ＝W Total weight of ÷V Discharging speed ………(4)
Wherein:
S time of feeding : the time (in seconds) required to throw all of the material in.
Step 5: the time required for feeding the wire is calculated. I.e. the time interval from the start of feeding to the end of feeding, the length of the time being defined by the length of all filaments to be fed (denoted as L Length of wire feed ) And the speed of the wire feeder (noted: v (V) Wire feeding speed ) And (5) determining.
The method for calculating the feeding time of all the materials comprises the following steps:
S wire feeding time ＝L Length of wire feed ÷V Wire feeding speed ………(5)
Wherein:
S wire feeding time : the time (in seconds) required for feeding the wire.
Step 6: the natural temperature drop of the molten steel is calculated, namely the initial temperature moment (recorded as M) of the molten steel measured by a temperature measuring probe Temperature measurement time ) By the planned heat end time (noted: m is M End time ) The heat of outward diffusion of molten steel through the ladle causes a temperature drop of molten steel (noted as: t (T) Natural temperature drop )。
The molten steel temperature drop calculation method from the time of measuring the initial temperature to the time of planning the end of the heat is as follows:
T natural temperature drop ＝W Weight of molten steel ×(M End time -M Temperature measurement time )×λ Coefficient of natural temperature drop ..(6)
Wherein:
λ coefficient of natural temperature drop : the natural temperature drop coefficient (unit: DEG C/t/min) of molten steel.
W Weight of molten steel : total weight of molten steel (unit: t).
Step 7: and calculating the temperature drop value of bottom blowing to molten steel under the condition of controlling the standard bottom blowing flow. In the whole LF treatment process, only two bottom blowing modes exist, namely weak bottom blowing and strong bottom blowing. The standard bottom blowing flow rate is a standard bottom blowing flow rate set for each process according to the requirement of the steelmaking process, such as: the weak bottom blowing standard flow is F Weak bottom blowing standard The bottom blowing flow is mainly set when feeding and feeding wires, and the weak bottom blowing standard flow is the upper limit bottom blowing flow in the treatment process; the standard flow of strong bottom blowing is F Strong bottom blowing standard The method is mainly used for setting the standard of the flow in the rest treatment processes, the standard flow of the strong bottom blowing is a lower flow limiting value, and in the actual production process, if the temperature of molten steel is too high, the strong bottom blowing flow can be increased to reduce the temperature of the molten steel, so that the purpose of controlling the temperature of the molten steel is achieved, and in the following step, the control of the temperature of the molten steel by bottom blowing is realized by mainly adjusting the strong bottom blowing flow.
The bottom blowing time calculation method of the weak bottom blowing flow comprises the following steps:
S weak and weak ＝S Time of feeding +S Wire feeding time ......(7)
The bottom blowing time calculation method of the strong bottom blowing flow comprises the following steps:
S strong strength ＝(M End time -M Temperature measurement time )-S Weak and weak ......(8)
The method for calculating the temperature drop of molten steel caused by strong and weak bottom blowing comprises the following steps:
T bottom blowing temperature drop ＝S Strong strength ×β Strong bottom blowing temperature drop coefficient +S Weak and weak ×β Weak bottom blowing temperature drop coefficient ..(9)
Wherein:
S time of feeding : the time (in seconds) required to throw all the material in;
S wire feeding time : the time (unit: seconds) required for feeding the wire;
S weak and weak : time of weak bottom blowing (unit: seconds);
S strong strength : time of strong bottom blowing (unit: seconds);
β weak bottom blowing temperature drop coefficient : the temperature drop coefficient (unit is DEG C/second) of the weak bottom blowing standard flow;
T bottom blowing temperature drop : bottom blowing causes temperature drop (unit: DEG C) of molten steel;
β strong bottom blowing temperature drop coefficient : the temperature drop coefficient (unit:. Degree.C/s) of the standard flow of the strong bottom blowing.
Step 8: the set value of the strong bottom blowing flow is calculated, and the set value is specifically as follows: the molten steel temperature calculation method at the end of the predicted heat is as follows:
T ending ＝T Initial initiation +T Bottom blowing temperature drop +T Material +T Natural temperature drop ..(10)
Wherein:
T material : after all materials are put into the furnace, the temperature of molten steel is changed (unit is shown in DEG C);
T natural temperature drop : the heat of outward diffusion of molten steel through a ladle causes the temperature drop (unit: DEG C) of molten steel;
T bottom blowing temperature drop : bottom blowing causes temperature drop (unit: DEG C) of molten steel;
T initial initiation : the initial temperature (unit is DEG C) measured by a temperature measuring probe;
T ending : predicted temperature (in degrees C.) when the heat ends at the scheduled time.
The method for calculating the predicted strong bottom blowing flow rate comprises the following steps:
the predicted temperature T at the end of the heat will be compared below Ending And a target temperature T Target object The flow value of the strong bottom blowing is calculated in three different cases, respectively.
When T is Ending <T Target object When (1): indicating that the predicted outlet temperature is insufficient by the end of the heat, and electrode heating is needed to increase the temperature of molten steel; the missing temperature delta T is sent to a heating model, and the heating model controls the electrode to heat; the strong bottom blowing flow is set according to the strong bottom blowing standard flow, namely: strong bottom blowing lower limit flow F Strong bottom blowing standard 。
F Strong bottom blowing ＝F Strong bottom blowing standard ..(11)
When T is Ending ＝T Target object When (1): when the furnace is finished, the predicted outlet temperature is equal to the target temperature, electrode heating is not needed, and the strong bottom blowing flow is set according to the strong bottom blowing standard flow, namely: strong bottom blowing lower limit flow F Strong bottom blowing standard 。
F Strong bottom blowing ＝F Strong bottom blowing standard ..(12)
When T is Ending >T Target object When (1): indicating that the predicted outlet temperature is greater than the target temperature by the end of the heat, it is necessary to increase the normal bottom blowing flow rate to lower the molten steel temperature so that the outlet temperature is equal to the target temperature.
F Strong bottom blowing ＝(T Ending -T Target object )÷δ Bottom blowing temperature drop coefficient ..(13)
Wherein:
δ bottom blowing temperature drop coefficient : the bottom blowing temperature drop coefficient (unit: DEG C/L/min).
F Strong bottom blowing : and calculating the flow rate (unit: L/min) of the strong bottom blowing.
Step 9: and (3) issuing a bottom blowing flow value to L1, and controlling the bottom blowing flow. After the calculation of the strong bottom blowing flow is completed, F is calculated Strong bottom blowing Strong bottom blowing flow value F Weak bottom blowing standard The weak bottom blowing standard flow value is issued to the corresponding flow set value of the primary system according to the LF different processing procedures, and a flow starting instruction is sent to the primary system, and the primary system completes the task of executing the flow set.
The 9 steps describe the control method for LF bottom blowing in detail, wherein the key step is the 8 th step, the time of each treatment process such as wire feeding, feeding and the like of LF treatment is fully considered, and the flow prediction value of strong bottom blowing is finally calculated through calculation of the strong bottom blowing time and the weak bottom blowing time of LF, so that the uniformity of molten steel temperature is ensured, and the molten steel temperature is accurately controlled to be equal to or close to the target temperature at the end of LF treatment, so that the production cost of LF is reduced. The main treatment function of LF bottom blowing argon treatment on molten steel is as follows: uniform molten steel composition, uniform molten steel temperature, promotion of molten steel desulfurization and temperature control. In the existing LF bottom blowing treatment production process, the control method for the molten steel temperature comprises the following steps: raising the temperature of the molten steel by electrode heating; the temperature is controlled by adjusting the bottom blowing flow to control the temperature falling speed of molten steel; however, in the actual operation process, if the temperature of the molten steel is not measured for many times, the bottom blowing time and flow rate are difficult to accurately and stably control, and if the bottom blowing flow rate is suddenly high and suddenly low, the temperature of the molten steel is not uniform. The invention mainly uses the calculation method of LF bottom blowing to control the molten steel temperature, accurately calculates the stable flow of LF bottom blowing in the molten steel bottom blowing process, ensures the uniformity of the molten steel temperature, and accurately controls the molten steel temperature to be equal to the target temperature at the end of LF treatment, thereby reducing the consumption of bottom blowing argon and electricity consumption in the LF production process, and has remarkable effect.
According to the method for controlling the molten steel temperature by LF bottom blowing argon, the stable bottom blowing flow set value is obtained through calculation, and the outbound temperature and the target are kept basically consistent within the minimum deviation range under the condition of ensuring the stability of the bottom blowing flow, so that the cost of the bottom blowing argon and the electricity consumption in the LF production process is effectively reduced, and in the test stage, after the method is used for LF bottom blowing control, the temperature hit rate of LF is improved from 93.4% to 95.8%, and the LF production cost is reduced by 100 yuan/furnace.
Drawings
FIG. 1 is a flow chart of LF bottom blowing argon to control molten steel temperature.
The specific embodiment is as follows:
in order to enhance the understanding of the present invention, the present embodiment will be described in detail with reference to the accompanying drawings.
Example 1: referring to fig. 1, a method for controlling the temperature of molten steel by LF bottom-blowing argon gas includes the steps of:
step 1: the method comprises the steps of obtaining data, and obtaining the weight of molten steel in the current treatment heat, the initial temperature of the molten steel, the target temperature of the molten steel, the planned LF treatment ending time and other data through a secondary process control system. The type and weight of the materials (including the type and length of wire feeding) needed to be put into the molten steel of the furnace are obtained from the LF alloy model, and all the data are calculated by the alloy model at the beginning of the heat.
Step 2: the initial temperature of the molten steel was measured using a temperature probe. After the furnace enters the station, the temperature of the molten steel is measured by a temperature measuring probe, thereby obtaining the initial temperature of the molten steel (marked as T Initial initiation )。:
Step 3: and calculating the temperature change of the input material to the molten steel. The calculation result of the alloy model is obtained in the step 1, and comprises the type and weight of the materials required to be input (the weight of each material is recorded as W i ) The step is mainly to calculate the change of the temperature of the molten steel after the materials are put into the molten steel (the temperature drop after each material is put into is recorded as: t (T) i ) Wherein, the temperature change coefficient of each material is:the density of each yarn was: alpha i 。
The calculation method for converting the wire feeding length into weight comprises the following steps:
W i ＝L i ×α i ………(1)
the method for calculating the temperature change of molten steel caused by feeding each material comprises the following steps:
the method for calculating the temperature change of molten steel caused by feeding all materials comprises the following steps:
T material ＝T 1 +T 2 +...+T i ………(3)
Wherein:
T material : after all materials are put intoTemperature change (unit: DEG C) of molten steel; if negative, the molten steel temperature decreases, and if positive, the molten steel temperature increases.
Step 4: the time required for feeding was calculated. I.e. the time interval from the start of feeding to the completion of feeding, the length of time being determined by the total weight of all the materials to be fed (denoted as W Total weight of ) And the blanking speed of the feeding and collecting hopper (recorded as: v (V) Discharging speed ) And (5) determining.
The method for calculating the feeding time of all the materials comprises the following steps:
S time of feeding ＝W Total weight of ÷V Discharging speed ………(4)
Wherein:
S time of feeding : the time (in seconds) required to throw all of the material in.
Step 5: the time required for feeding the wire is calculated. I.e. the time interval from the start of feeding to the end of feeding, the length of the time being defined by the length of all filaments to be fed (denoted as L Length of wire feed ) And the speed of the wire feeder (noted: v (V) Wire feeding speed ) And (5) determining.
The method for calculating the feeding time of all the materials comprises the following steps:
S wire feeding time ＝L Length of wire feed ÷V Wire feeding speed ………(5)
Wherein:
S wire feeding time : the time (in seconds) required for feeding the wire.
Step 6: and calculating the natural temperature drop of the molten steel. Namely, the initial temperature moment (M is recorded as Temperature measurement time ) By the planned heat end time (noted: m is M End time ) The heat of outward diffusion of molten steel through the ladle causes a temperature drop of molten steel (noted as: t (T) Natural temperature drop )。
The molten steel temperature drop calculation method from the time of measuring the initial temperature to the time of planning the end of the heat is as follows:
T natural temperature drop ＝W Weight of molten steel ×(M End time -M Temperature measurement time )×λ Coefficient of natural temperature drop ..(6)
Wherein:
λ coefficient of natural temperature drop : the natural temperature drop coefficient (unit: DEG C/t/min) of molten steel.
W Weight of molten steel : total weight of molten steel (unit: t).
Step 7: and calculating the temperature drop value of bottom blowing to molten steel under the condition of controlling the standard bottom blowing flow. In the whole LF treatment process, only two bottom blowing modes exist, namely weak bottom blowing and strong bottom blowing. The standard bottom blowing flow rate is a standard bottom blowing flow rate set for each process according to the requirement of the steelmaking process, such as: the weak bottom blowing standard flow is F Weak bottom blowing standard The bottom blowing flow is mainly set when feeding and feeding wires, and the weak bottom blowing standard flow is the upper limit bottom blowing flow in the treatment process; the standard flow of strong bottom blowing is F Strong bottom blowing standard The method is mainly used for setting the standard of the flow in the rest treatment processes, the standard flow of the strong bottom blowing is a lower flow limiting value, and in the actual production process, if the temperature of molten steel is too high, the strong bottom blowing flow can be increased to reduce the temperature of the molten steel, so that the purpose of controlling the temperature of the molten steel is achieved, and in the following step, the control of the temperature of the molten steel by bottom blowing is realized by mainly adjusting the strong bottom blowing flow.
The bottom blowing time calculation method of the weak bottom blowing flow comprises the following steps:
S weak and weak ＝S Time of feeding +S Wire feeding time ......(7)
The bottom blowing time calculation method of the strong bottom blowing flow comprises the following steps:
S strong strength ＝(M End time -M Temperature measurement time )-S Weak and weak ......(8)
The method for calculating the temperature drop of molten steel caused by strong and weak bottom blowing comprises the following steps:
T bottom blowing temperature drop ＝S Strong strength ×β Strong bottom blowing temperature drop coefficient +S Weak and weak ×β Weak bottom blowing temperature drop coefficient ..(9)
Wherein:
S time of feeding : the time (in seconds) required to throw all the material in;
S wire feedingTime : the time (unit: seconds) required for feeding the wire;
S weak and weak : time of weak bottom blowing (unit: seconds);
S strong strength : time of strong bottom blowing (unit: seconds);
β weak bottom blowing temperature drop coefficient : the temperature drop coefficient (unit is DEG C/second) of the weak bottom blowing standard flow;
T bottom blowing temperature drop : bottom blowing causes temperature drop (unit: DEG C) of molten steel;
β strong bottom blowing temperature drop coefficient : the temperature drop coefficient (unit:. Degree.C/s) of the standard flow of the strong bottom blowing.
Step 8: and calculating a set value of the strong bottom blowing flow.
The molten steel temperature calculation method at the end of the predicted heat is as follows:
T ending ＝T Initial initiation +T Bottom blowing temperature drop +T Material +T Natural temperature drop ..(10)
Wherein:
T material : after all materials are put into the furnace, the temperature of molten steel is changed (unit is shown in DEG C);
T natural temperature drop : the heat of outward diffusion of molten steel through a ladle causes the temperature drop (unit: DEG C) of molten steel;
T bottom blowing temperature drop : bottom blowing causes temperature drop (unit: DEG C) of molten steel;
T initial initiation : the initial temperature (unit is DEG C) measured by a temperature measuring probe;
T ending : predicted temperature (in degrees C.) when the heat ends at the scheduled time.
The method for calculating the predicted strong bottom blowing flow rate comprises the following steps:
the predicted temperature T at the end of the heat will be compared below Ending And a target temperature T Target object The flow value of the strong bottom blowing is calculated in three different cases, respectively.
When T is Ending <T Target object When (1): indicating that the predicted outlet temperature is insufficient by the end of the heat, and electrode heating is needed to increase the temperature of molten steel; send the missing temperature delta T to the addingA thermal model for controlling the electrode to heat by the heating model; the strong bottom blowing flow is set according to the strong bottom blowing standard flow, namely: strong bottom blowing lower limit flow F Strong bottom blowing standard 。
F Strong bottom blowing ＝F Strong bottom blowing standard ..(11)
When T is Ending ＝T Target object When (1): when the furnace is finished, the predicted outlet temperature is equal to the target temperature, electrode heating is not needed, and the strong bottom blowing flow is set according to the strong bottom blowing standard flow, namely: strong bottom blowing lower limit flow F Strong bottom blowing standard 。
F Strong bottom blowing ＝F Strong bottom blowing standard ..(12)
When T is Ending >T Target object When (1): indicating that the predicted outlet temperature is greater than the target temperature by the end of the heat, it is necessary to increase the normal bottom blowing flow rate to lower the molten steel temperature so that the outlet temperature is equal to the target temperature.
F Strong bottom blowing ＝(T Ending -T Target object )÷δ Bottom blowing temperature drop coefficient ..(13)
Wherein:
δ bottom blowing temperature drop coefficient : the bottom blowing temperature drop coefficient (unit: DEG C/L/min).
F Strong bottom blowing : and calculating the flow rate (unit: L/min) of the strong bottom blowing.
Step 9: and (3) issuing a bottom blowing flow value to L1, and controlling the bottom blowing flow. After the calculation of the strong bottom blowing flow is completed, F is calculated Strong bottom blowing Strong bottom blowing flow value F Weak bottom blowing standard The weak bottom blowing standard flow value is issued to the corresponding flow set value of the primary system according to the LF different processing procedures, and a flow starting instruction is sent to the primary system, and the primary system completes the task of executing the flow set.
Specific examples: the method for controlling the temperature of molten steel by LF bottom blowing argon comprises the following steps:
step 1: data is acquired. And obtaining data such as the weight of molten steel in the current treatment heat, the initial temperature of the molten steel, the target temperature of the molten steel, the planned LF treatment ending time and the like through a secondary process control system. The type and weight of the materials (including the type and length of wire feeding) needed to be put into the molten steel of the furnace are obtained from the LF alloy model, and all the data are calculated by the alloy model at the beginning of the heat. (see sample table 1, sample table 2 for relevant data).
Examples table 1 basic information of LF finery was obtained
EXAMPLES Table 2LF alloy model calculation results information Table
Step 2: the initial temperature of the molten steel was measured using a temperature probe. After the furnace enters the station, the temperature of the molten steel is measured by a temperature measuring probe, thereby obtaining the initial temperature of the molten steel (marked as T Initial initiation )。
In this example, after the heat LF enters the station, the measured initial temperature is: 1562 ℃ C:
step 3: and calculating the temperature change of the input material to the molten steel. The calculation result of the alloy model is obtained in the step 1, and comprises the type and weight of the materials required to be input (the weight of each material is recorded as W i ) The step is mainly to calculate the change of the temperature of the molten steel after the materials are put into the molten steel (the temperature drop after each material is put into is recorded as: t (T) i ) Wherein, the temperature change coefficient of each material is:the density of each yarn was: alpha i 。
The calculation method for converting the wire feeding length into weight comprises the following steps:
W i ＝L i ×α i ………(1)
the method for calculating the temperature change of molten steel caused by feeding each material comprises the following steps:
the method for calculating the temperature change of molten steel caused by feeding all materials comprises the following steps:
T material ＝T 1 +T 2 +...+T i ………(3)
Wherein:
T material : after all materials are put into the furnace, the temperature of molten steel is changed (unit is shown in DEG C); if negative, the molten steel temperature decreases, and if positive, the molten steel temperature increases.
Step 4: the time required for feeding was calculated. I.e. the time interval from the start of feeding to the completion of feeding, the length of time being determined by the total weight of all the materials to be fed (denoted as W Total weight of ) And the blanking speed of the feeding and collecting hopper (recorded as: v (V) Discharging speed ) And (5) determining.
The method for calculating the feeding time of all the materials comprises the following steps:
S time of feeding ＝W Total weight of ÷V Discharging speed ………(4)
Wherein:
S time of feeding : the time (in seconds) required to throw all of the material in.
V Discharging speed : the feeding speed (unit: kg/second) of the feeding and collecting hopper.
Step 5: the time required for feeding the wire is calculated. I.e. the time interval from the start of feeding to the end of feeding, the length of the time being defined by the length of all filaments to be fed (denoted as L Length of wire feed ) And the speed of the wire feeder (noted: v (V) Wire feeding speed ) And (5) determining.
The method for calculating the feeding time of all the materials comprises the following steps:
S wire feeding time ＝L Length of wire feed ÷V Wire feeding speed ………(5)
Wherein:
S wire feeding time : the time (in seconds) required for feeding the wire.
Step 6: and calculating the natural temperature drop of the molten steel. Namely, the initial temperature moment (M is recorded as Temperature measurement time ) By the planned heat end time (noted: m is M End time ) The heat of outward diffusion of molten steel through the ladle causes a temperature drop of molten steel (noted as: t (T) Natural temperature drop )。
The molten steel temperature drop calculation method from the time of measuring the initial temperature to the time of planning the end of the heat is as follows:
T natural temperature drop ＝W Weight of molten steel ×(M End time -M Temperature measurement time )×λ Coefficient of natural temperature drop ..(6)
Wherein:
λ coefficient of natural temperature drop : the natural temperature drop coefficient (unit: DEG C/t/min) of molten steel.
W Weight of molten steel : total weight of molten steel (unit: t).
Step 7: and calculating the temperature drop value of bottom blowing to molten steel under the condition of controlling the standard bottom blowing flow. In the whole LF treatment process, only two bottom blowing modes exist, namely weak bottom blowing and strong bottom blowing. The standard bottom blowing flow rate is a standard bottom blowing flow rate set for each process according to the requirement of the steelmaking process, such as: the weak bottom blowing standard flow is F Weak bottom blowing standard The bottom blowing flow is mainly set when feeding and feeding wires, and the weak bottom blowing standard flow is the upper limit bottom blowing flow in the treatment process; the standard flow of strong bottom blowing is F Strong bottom blowing standard The method is mainly used for setting the standard of the flow in the rest treatment processes, the standard flow of the strong bottom blowing is a lower flow limiting value, and in the actual production process, if the temperature of molten steel is too high, the strong bottom blowing flow can be increased to reduce the temperature of the molten steel, so that the purpose of controlling the temperature of the molten steel is achieved, and in the following steps, the strong bottom blowing flow is mainly regulated to control the temperature of the molten steel by bottom blowing.
The bottom blowing time calculation method of the weak bottom blowing flow comprises the following steps:
S weak and weak ＝S Time of feeding +S Wire feeding time ......(7)
The bottom blowing time calculation method of the strong bottom blowing flow comprises the following steps:
S strong strength ＝(M End time -M Temperature measurement time )-S Weak and weak ......(8)
The method for calculating the temperature drop of molten steel caused by strong and weak bottom blowing comprises the following steps:
T bottom blowing temperature drop ＝S Strong strength ×β Strong bottom blowing temperature drop coefficient +S Weak and weak ×β Weak bottom blowing temperature drop coefficient ..(9)
Wherein:
S time of feeding : the time (in seconds) required to throw all the material in;
S wire feeding time : the time (unit: seconds) required for feeding the wire;
S weak and weak : time of weak bottom blowing (unit: seconds);
S strong strength : time of strong bottom blowing (unit: seconds);
β weak bottom blowing temperature drop coefficient : the temperature drop coefficient (unit is DEG C/second) of the weak bottom blowing standard flow;
T bottom blowing temperature drop : bottom blowing causes temperature drop (unit: DEG C) of molten steel;
β strong bottom blowing temperature drop coefficient : the temperature drop coefficient (unit:. Degree.C/s) of the standard flow of the strong bottom blowing.
Step 8: and calculating a set value of the strong bottom blowing flow.
The molten steel temperature calculation method at the end of the predicted heat is as follows:
T ending ＝T Initial initiation +T Bottom blowing temperature drop +T Material +T Natural temperature drop ..(10)
Wherein:
T material : after all materials are put into the furnace, the temperature of molten steel is changed (unit is shown in DEG C);
T natural temperature drop : the heat of outward diffusion of molten steel through a ladle causes the temperature drop (unit: DEG C) of molten steel;
T bottom blowing temperature drop : bottom blowing causes temperature drop (unit: DEG C) of molten steel;
T initial initiation : the initial temperature (unit is DEG C) measured by a temperature measuring probe;
T ending : predicted temperature (in degrees C.) when the heat ends at the scheduled time.
The method for calculating the strong pre-strong bottom blowing flow comprises the following steps:
the predicted temperature T at the end of the heat will be compared below Ending And a target temperature T Target object The flow value of the strong bottom blowing is calculated in three different cases, respectively.
When T is Ending <T Target object When (1): indicating that the predicted outlet temperature is insufficient by the end of the heat, and electrode heating is needed to increase the temperature of molten steel; the missing temperature delta T is sent to a heating model, and the heating model controls the electrode to heat; the strong bottom blowing flow is set according to the strong bottom blowing standard flow, namely: strong bottom blowing lower limit flow F Strong bottom blowing standard 。
F Strong bottom blowing ＝F Strong bottom blowing standard ..(11)
When T is Ending ＝T Target object When (1): when the furnace is finished, the predicted outlet temperature is equal to the target temperature, electrode heating is not needed, and the strong bottom blowing flow is set according to the strong bottom blowing standard flow, namely: strong bottom blowing lower limit flow F Strong bottom blowing standard 。
F Strong bottom blowing ＝F Strong bottom blowing standard ..(12)
When T is Ending >T Target object When (1): indicating that the predicted outlet temperature is greater than the target temperature by the end of the heat, it is necessary to increase the normal bottom blowing flow rate to lower the molten steel temperature so that the outlet temperature is equal to the target temperature.
F Strong bottom blowing ＝(T Ending -T Target object )÷δ Bottom blowing temperature drop coefficient ..(13)
Wherein:
δ bottom blowing temperature drop coefficient : the bottom blowing temperature drop coefficient (unit: DEG C/L/min).
F Strong bottom blowing : strong strengthBottom blowing flow calculation (unit: L/min).
Step 9: and (3) issuing a bottom blowing flow value to L1, and controlling the bottom blowing flow. After the calculation of the strong bottom blowing flow is completed, F is calculated Strong bottom blowing Strong bottom blowing flow value F Weak bottom blowing standard The weak bottom blowing standard flow value is issued to the corresponding flow set value of the primary system according to the LF different processing procedures, and a flow starting instruction is sent to the primary system, and the primary system completes the task of executing the flow set.
In the process of controlling the temperature of molten steel by LF bottom blowing argon, the bottom blowing flow is difficult to accurately and stably control, and the factors influencing the temperature of the molten steel are very many, so that the outlet temperature of the molten steel cannot be accurately controlled, and the cost of argon and electricity consumption is increased; after the background blowing control method is introduced, a stable flow set value of LF bottom blowing argon in the LF treatment process of molten steel can be accurately calculated to ensure uniformity of molten steel temperature, and the molten steel temperature is accurately controlled to be equal to or close to a target temperature at the end of LF treatment, so that consumption of the bottom blowing argon and power consumption in the LF production process is reduced.
In the test stage, after the bottom blowing control is carried out by using the method for controlling the temperature of molten steel by using the LF bottom blowing argon, the LF bottom blowing argon consumption and the electricity consumption cost are obviously reduced, the LF temperature hit rate is improved to 95.8% from the original 93.4%, the LF production cost is reduced by 100 yuan/furnace, and the effect is obvious.
It should be noted that the above-mentioned embodiments are not intended to limit the scope of the present invention, and equivalent changes or substitutions made on the basis of the above-mentioned technical solutions fall within the scope of the present invention as defined in the claims.
Claims (10)
1. A method for controlling the temperature of molten steel by LF bottom blowing argon, which is characterized by comprising the following steps:
step 1: the data is acquired and the data is acquired,
step 2: measuring the initial temperature of molten steel by using a temperature measuring probe;
step 3: calculating the temperature change of the input material to molten steel;
step 4: calculating the time required by feeding;
step 5: calculating the time required for feeding the wire;
step 6: calculating the natural temperature drop of molten steel;
step 7: calculating the temperature drop value of bottom blowing to molten steel under the condition of controlling the standard bottom blowing flow;
step 8: calculating a set value of the strong bottom blowing flow;
step 9: and (3) issuing a bottom blowing flow value to L1, and controlling the bottom blowing flow.
2. The method for controlling the temperature of molten steel by LF bottom-blowing argon gas according to claim 1, wherein step 1: the method comprises the steps of obtaining data, obtaining the weight of molten steel in the current treatment heat, the initial temperature of the molten steel, the target temperature of the molten steel, the planned LF treatment ending time and the like through a secondary process control system, and obtaining the type and the weight of materials needed to be input in the molten steel in the furnace from an LF alloy model.
3. The method for controlling the temperature of molten steel by LF bottom-blowing argon gas according to claim 2, wherein step 2: the initial temperature of molten steel is measured by using a temperature measuring probe, and after the furnace enters a station, the temperature of the molten steel is measured by using the temperature measuring probe, so that the initial temperature of the molten steel is obtained and is recorded as: t (T) Initial initiation 。
4. The method for controlling the temperature of molten steel by LF-bottom blowing argon gas according to claim 3, wherein step 3: calculating the temperature change of the input materials to molten steel, wherein the calculation result of the alloy model is obtained in the step 1, and comprises the type and weight of the input materials (the weight of each material is recorded as W i ) This step is mainly to calculate the change of the temperature of the molten steel after these materials are put into the molten steel (the temperature drop after each material is put into is noted as: t (T) i ) Wherein, the temperature change coefficient of each material is:the density of each yarn was: alpha i ；
The calculation method for converting the wire feeding length into weight comprises the following steps:
W i ＝L i ×α i ………(1)；
the method for calculating the temperature change of molten steel caused by feeding each material comprises the following steps:
the method for calculating the temperature change of molten steel caused by feeding all materials comprises the following steps:
T material ＝T 1 +T 2 +...+T i ………(3)；
Wherein:
T material : after all materials are put into the furnace, the temperature of molten steel is changed (unit is shown in DEG C); if negative, the molten steel temperature decreases, and if positive, the molten steel temperature increases.
5. The method for controlling the temperature of molten steel by LF bottom-blowing argon gas according to claim 4, wherein step 4: the time required for feeding is calculated, namely the time interval from the start of feeding to the completion of feeding, and the time is calculated from the total weight of all materials required to be fed (recorded as W Total weight of ) And the blanking speed of the feeding and collecting hopper (recorded as: v (V) Discharging speed ) Determining;
the method for calculating the feeding time of all the materials comprises the following steps:
S time of feeding ＝W Total weight of ÷V Discharging speed ………(4)
Wherein:
S time of feeding : the time (in seconds) required to throw all of the material in.
6. The method for controlling the temperature of molten steel by LF bottom-blowing argon gas according to claim 5, wherein step 5: calculating the time required for feeding the yarn, namely the time interval from the start of feeding the yarn to the end of feeding the yarn, wherein the time is calculated from the length of all the yarns to be fed (recorded as L Length of wire feed ) And the speed of the wire feeder (noted: v (V) Wire feeding speed ) It is decided that the method comprises the steps of,
the method for calculating the feeding time of all the materials comprises the following steps:
S wire feeding time ＝L Length of wire feed ÷V Wire feeding speed ………(5)
Wherein:
S wire feeding time : the time (in seconds) required for feeding the wire.
7. The method for controlling the temperature of molten steel by LF bottom-blowing argon gas according to claim 6, wherein step 6: the natural temperature drop of the molten steel is calculated, namely the initial temperature moment (recorded as M) of the molten steel measured by a temperature measuring probe Temperature measurement time ) By the planned heat end time (noted: m is M End time ) The heat of outward diffusion of molten steel through the ladle causes a temperature drop of molten steel (noted as: t (T) Natural temperature drop )；
The molten steel temperature drop calculation method from the time of measuring the initial temperature to the time of planning the end of the heat is as follows:
T natural temperature drop ＝W Weight of molten steel ×(M End time -M Temperature measurement time )×λ Coefficient of natural temperature drop ..(6)
Wherein:
λ coefficient of natural temperature drop : the natural temperature drop coefficient (unit: DEG C/t/min) of molten steel;
W weight of molten steel : total weight of molten steel (unit: t).
8. The method for controlling the temperature of molten steel by LF bottom-blowing argon gas according to claim 6, wherein step 7: under the condition of standard bottom blowing flow control, the bottom blowing temperature drop value of molten steel is calculated, and only two bottom blowing modes exist in the whole LF treatment process, namely, weak bottom blowing and strong bottom blowing, and the bottom blowing time calculation method of the weak bottom blowing flow comprises the following steps:
S weak and weak ＝S Time of feeding +S Wire feeding time ......(7)
The bottom blowing time calculation method of the strong bottom blowing flow comprises the following steps:
S strong strength ＝(M End time -M Temperature measurement time )-S Weak and weak ......(8)
The method for calculating the temperature drop of molten steel caused by strong and weak bottom blowing comprises the following steps:
T bottom blowing temperature drop ＝S Strong strength ×β Strong bottom blowing temperature drop coefficient +S Weak and weak ×β Weak bottom blowing temperature drop coefficient ..(9)
Wherein:
S time of feeding : the time (in seconds) required to throw all the material in;
S wire feeding time : the time (unit: seconds) required for feeding the wire;
S weak and weak : time of weak bottom blowing (unit: seconds);
S strong strength : time of strong bottom blowing (unit: seconds);
β weak bottom blowing temperature drop coefficient : the temperature drop coefficient (unit is DEG C/second) of the weak bottom blowing standard flow;
T bottom blowing temperature drop : bottom blowing causes temperature drop (unit: DEG C) of molten steel;
β strong bottom blowing temperature drop coefficient : the temperature drop coefficient (unit:. Degree.C/s) of the standard flow of the strong bottom blowing.
9. The method for controlling the temperature of molten steel by LF bottom-blown argon of claim 6,
step 8: the set value of the strong bottom blowing flow is calculated, and the set value is specifically as follows: the molten steel temperature calculation method at the end of the predicted heat is as follows:
T ending ＝T Initial initiation +T Bottom blowing temperature drop +T Material +T Natural temperature drop ..(10)
Wherein:
T material : after all materials are put into the furnace, the temperature of molten steel is changed (unit is shown in DEG C);
T natural temperature drop : the heat of outward diffusion of molten steel through a ladle causes the temperature drop (unit: DEG C) of molten steel;
T bottom blowing temperature drop : bottom blowing causes temperature drop (unit: DEG C) of molten steel;
T initial initiation : the initial temperature (unit is DEG C) measured by a temperature measuring probe;
T ending : predicted temperature (in degrees C.) when the heat ends at the scheduled time.
The method for calculating the predicted strong bottom blowing flow rate comprises the following steps:
the predicted temperature T at the end of the heat will be compared below Ending And a target temperature T Target object Respectively calculating the flow value of the strong bottom blowing under three different conditions;
when T is Ending <T Target object When (1): indicating that the predicted outlet temperature is insufficient by the end of the heat, and electrode heating is needed to increase the temperature of molten steel; the missing temperature delta T is sent to a heating model, and the heating model controls the electrode to heat; the strong bottom blowing flow is set according to the strong bottom blowing standard flow, namely: strong bottom blowing lower limit flow F Strong bottom blowing standard ；
F Strong bottom blowing ＝F Strong bottom blowing standard ..(11)
When T is Ending ＝T Target object When (1): when the furnace is finished, the predicted outlet temperature is equal to the target temperature, electrode heating is not needed, and the strong bottom blowing flow is set according to the strong bottom blowing standard flow, namely: strong bottom blowing lower limit flow F Strong bottom blowing standard ；
F Strong bottom blowing ＝F Strong bottom blowing standard ..(12)
When T is Ending >T Target object When (1): when the furnace time is over, the predicted outlet temperature is larger than the target temperature, and the normal bottom blowing flow is required to be increased to reduce the temperature of molten steel, so that the outlet temperature is equal to the target temperature;
F strong bottom blowing ＝(T Ending -T Target object )÷δ Bottom blowing temperature drop coefficient ..(13)；
Wherein:
δ bottom blowing temperature drop coefficient : the bottom blowing temperature drop coefficient (unit: DEG C/L/min);
F strong bottom blowing : and calculating the flow rate (unit: L/min) of the strong bottom blowing.
10. The method for controlling the temperature of molten steel by LF bottom-blowing argon gas according to claim 6, wherein step 9: issuing a bottom blowing flow value to L1, controlling the bottom blowing flow, and after finishing the calculation of the strong bottom blowing flow, calculating the F Strong bottom blowing Strong bottom blowing flow value F Weak bottom blowing standard The weak bottom blowing standard flow value is issued to the corresponding flow set value of the primary system according to the LF different processing procedures, and a flow starting instruction is sent to the primary system, and the primary system completes the task of executing the flow set.
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