CN112808960A - Tundish preheating automatic control method based on continuous temperature measurement - Google Patents
Tundish preheating automatic control method based on continuous temperature measurement Download PDFInfo
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- CN112808960A CN112808960A CN201911123412.3A CN201911123412A CN112808960A CN 112808960 A CN112808960 A CN 112808960A CN 201911123412 A CN201911123412 A CN 201911123412A CN 112808960 A CN112808960 A CN 112808960A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/005—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like with heating or cooling means
- B22D41/01—Heating means
- B22D41/015—Heating means with external heating, i.e. the heat source not being a part of the ladle
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Abstract
The invention relates to a continuous temperature measurement-based automatic tundish preheating control method, which mainly comprises the steps of pre-embedding an online temperature measuring thermocouple in a tundish through a three-dimensional positioning method and detecting the preheating temperature of the tundish in real time. According to the preheating temperature (1100-1300 ℃) of the target temperature of the tundish and the preheating time requirement of the tundish, the tundish is divided into four preheating intervals of small fire, medium fire, large fire and heat preservation. The temperature rise speed of the refractory material of the tundish is controlled, the temperature of a target interval is set for the corresponding preheating interval to realize normal preheating, the air excess coefficient range of the air-fuel ratio is set to control the length of combustion flame and the baking effect, and the automatic control method for preheating the tundish, which is controlled according to the target temperature, is realized. The method avoids the defect that the baking effect is judged by manual experience, simultaneously ensures the baking efficiency and avoids the hidden dangers of over-baking and under-fire of the baked refractory material by the real-time feedback control of the preheating process, saves the baking energy consumption to a certain extent and has obvious energy-saving effect.
Description
Technical Field
The invention relates to a control method, in particular to a tundish preheating automatic control method based on continuous temperature measurement, and belongs to the technical field of ferrous metallurgy tundish preheating.
Background
In the current continuous casting process in the steel industry, the online quick replacement of the tundish is a very mature and widely applied technology. The quick-change tundish can ensure the continuous production of the continuous casting process, and is the most basic technical guarantee for the stable and high yield of the continuous casting process. The tundish is quickly replaced, namely the tundish which reaches the service life is quickly driven away by a tundish car, meanwhile, a standby tundish which is well preheated to meet the requirement is carried to a production position (casting position) by the tundish car, and the important functions of stabilizing flow, shunting, floating and mixing and the like are achieved by continuously exerting the molten steel from a transition ladle of the tundish to a continuous casting crystallizer. In this process, the preheating process of the spare tundish is particularly important. It is desirable to allow the tundish to warm to the target process temperature within a specified time.
The preheating process of the tundish requires that the preheating can reach the temperature of over 1100 ℃ before the preheating is finished, so that the normal use of the tundish in the casting state can be ensured. At present, the preheating process of the tundish in the industry generally adopts the combustion of coal oxygen or other gases to realize the preheating of the tundish. This preheating is achieved by time-phased combustion gas flow control. The final baking effect and the baking temperature are realized by the empirical judgment of field workers. Because of depending on the manual judgment and control, the preheating of the tundish is most easy to generate the excessive preheating, the temperature of the preheating period of the tundish is too high, the abnormal cracking of the refractory material in the tundish is caused, and the production accident is caused when a new tundish is used due to the abnormality of other process parts (such as a stopper rod and a current stabilizer) of the tundish; similarly, due to the fact that manual judgment and control are adopted, the tundish preheating is easy to meet the requirement that the temperature cannot reach over 1100 ℃ of the process requirement, so that the new tundish absorbs too much heat when in use, and further malignant production accidents such as casting failure and the like caused by excessive temperature drop of continuous casting molten steel are caused.
Most of the existing tundish preheating processes focus on the development of preheating devices, such as a tundish baking device with application number CN201420286676, a tundish energy-saving baking system for continuous casting with application number CN201510650473 and a use process thereof, which are mainly focused on the development and improvement of the preheating devices, but the baking process is rarely improved. The only mention of the dynamic control device and control method for preheating the continuous casting submerged nozzle with the application number of CN201610510491 is that the preheating process of the tundish is controlled according to the preheating gas flow in a certain time period, so how to accurately and effectively utilize the existing continuous temperature measurement process to realize the automatic control of the preheating of the tundish, the process requirements of the tundish baking are quickly and effectively met, and no new process development and publication exist at present.
Disclosure of Invention
The invention provides a tundish preheating automatic control method based on continuous temperature measurement aiming at the problems in the prior art, and the method is based on the requirement of tundish preheating target temperature and realizes automatic baking of the tundish based on target temperature flow control through real-time feedback of thermocouple temperature pre-embedded in the tundish. The method avoids the defect that the baking effect is judged by manual experience, meanwhile, the baking efficiency is effectively ensured by the real-time feedback control of the preheating process, other baking consumption is saved to a certain extent, and the energy-saving effect is obvious.
In order to achieve the purpose, the technical scheme of the invention is that the tundish preheating automatic control method based on continuous temperature measurement comprises the following steps:
step 1, installing a continuous temperature measuring thermocouple head in a tundish by a three-dimensional positioning method;
and 2, dividing the preheating temperature into four preheating intervals of small fire, medium fire, large fire and heat preservation according to the target preheating temperature (1100-1300 ℃) of the tundish and the preheating time requirement of the tundish. Setting a segmented target temperature interval according to the temperature rise speed of the refractory material of the tundish, and setting the temperature of the target interval and the air excess coefficient of a set air-fuel ratio for the corresponding preheating interval;
step 3, collecting a continuous casting tundish position signal, a preheating ignition device signal and a preheating starting signal;
and 4, when the position signal of the tundish reaches a preheating position, the preheating ignition device is turned on and feeds back that the flow of the preheating medium of the ignition pipeline is more than 10m3/h, the preheating ignition device is successfully turned on, and a preheating starting signal is received, the preheating medium valve is turned on to preheat the tundish. The judgment of the flow of the ignition pipeline can ensure successful ignition, and the preheating explosion phenomenon caused by sudden ignition after the preheating medium is gathered due to long-time non-ignition is avoided;
and 5, executing small-fire preheating interval control, setting 8-12 segmented target temperature intervals, and controlling the temperature rise speed to be less than 50 ℃/min within the set segmented target temperature interval time. Controlling the flow of the preheating medium to be Q1, and controlling the flow to be Q1 within the target range and time of each preset cell if the temperature exceeds Tn + Ta; if the temperature is always less than Tn, the flow rate of the preheating medium is continuously controlled to be Q2. And setting an air excess coefficient of 1.35-1.45 according to a standard air-fuel ratio of the fuel, and controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium. The sectional target temperature interval is set, so that the temperature rise speed can be ensured to be within a controllable range, and the abnormal hidden dangers of cracking and bulging of the refractory material caused by too fast temperature rise during preheating of the tundish are solved. The air excess coefficient is set to be 1.35-1.45, the flame length can reach the bottom of the tundish, and high-temperature baking of the tundish cover is avoided;
and 6, after the preheating time reaches 1/4X, performing intermediate fire preheating interval control, setting 8-12 segmented target temperature intervals, and controlling the temperature rise speed to be less than 20 ℃/min within the set segmented target temperature interval time. Controlling the flow of the preheating medium to Q3, and controlling the flow to Q2 if the temperature exceeds Tn + Ta within a specified time of 1/4X; if the temperature is always less than Tn, continuously controlling the flow of the preheating medium at Q3; and controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium according to the standard air-fuel ratio of the fuel and the air excess coefficient of 1.25-1.35. The sectional target temperature interval is set, so that the temperature rise speed can be ensured to be within a controllable range, an ideal temperature rise effect can be realized at the stage, and constant temperature rise is achieved. The air excess coefficient is set to be 1.25-1.35, so that the full combustion of a preheating medium and the uniform preheating of the tundish wall are ensured;
and 7, after the preheating time reaches 1/2X, executing intense fire preheating interval control, setting 8-12 segmented target temperature intervals, and controlling the temperature rise speed to be less than 15 ℃/min within the set segmented target temperature interval time. : controlling the flow of the preheating medium to Q4, and controlling the flow to Q3 if the temperature exceeds Tn + Ta within a specified time of 1/2X; if the temperature is always less than Tn, the flow rate of the preheating medium is continuously controlled to be Q4. And controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium according to the standard air-fuel ratio of the fuel and the air excess coefficient of 1.25-1.35. The sectional target temperature interval is set, so that constant-speed temperature rise in a specified time can be ensured, and the temperature of the tundish can reach more than 1100 ℃. The air excess coefficient is set to be 1.25-1.35, so that the full combustion of a preheating medium and the uniform preheating of the tundish wall are ensured; (ii) a
And 8, after the preheating time reaches X, executing heat preservation and preheating interval control, and controlling the temperature fluctuation speed to be less than 5 ℃/min. Controlling the flow of the preheating medium to be Q3, and controlling the flow to be Q2 if the temperature exceeds T +10 degrees in the time before the preheating is stopped; if the temperature is always less than T, the flow of the preheating medium is continuously controlled to be Q4; controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium according to the standard air-fuel ratio of the adopted fuel and the air excess coefficient of 1.20-1.25;
and 9, receiving a preheating end signal, and ending the automatic preheating process.
As an improvement of the present invention, in step 1, the three-dimensional positioning method installs a continuous thermocouple head in a tundish, which specifically comprises the following steps:
1.1, positioning the thermocouple installation position at a position which is vertically 300mm-400mm away from the bottom of the tundish (Y-axis direction) and is vertically 600mm-800mm away from the side edge of the tundish (Z-axis direction);
1.2 the installation extension length of the thermocouple position is controlled to be 160mm-180mm (X-axis direction).
The installation method and the distance setting can ensure that the installation position and the extension length of the continuous temperature thermocouple in the tundish are fully ensured, so that the temperature of the inner cavity of the tundish can be accurately measured in the preheating time, the temperature of the outer flame of the baking flame is not measured, and the temperature measurement error can be controlled within +/-5 ℃.
As an improvement of the present invention, step 2 sets target interval temperatures in time division and interval division according to target temperature and tundish preheating time requirements, specifically as follows:
2.1 setting a target preheating temperature T and a target preheating time X;
2.2 setting the preheating target temperature, preheating time and upper and lower limits of the preheating energy medium in different stages according to the target preheating temperature T and the target preheating time X and according to the small fire stage, the medium fire stage, the large fire stage and the heat preservation stage; the preheating interval method can ensure the preheating temperature rise speed of the tundish within the specified time, and the baking temperature rise speed is controlled to be 15-60 ℃/min according to the current refractory material requirement, so that the refractory material can not crack. The preheating interval and the corresponding preheating target temperature set in the step can accurately control the baking temperature rise speed to be 45-50 ℃/min, and the stability of the preheated refractory material is improved.
2.3 setting and defining a temperature rise curve of each preheating interval according to the regulation and control precision of the energy medium valve and 8-12 time periods with target rise temperature Tn which are equally divided according to the target temperature interval and the preheating time;
2.4 setting a fluctuation range Ta (4-8 ℃) for the target temperature among the N small regions, and avoiding frequent adjustment of the valve; the innovative setting of the fluctuation range can avoid frequent actions of the medium regulating valve and ensure the service life and the period of the valve. By setting the fluctuation range, the valve action frequency can be reduced by 35 percent, and the service life of the valve is prolonged by 120 days.
Compared with the prior art, the invention has the advantages that 1) the technical scheme utilizes the tundish preheating control method of automatically adjusting the flow rate at the target temperature, thereby avoiding the defects of judging the online preheating temperature and the baking effect by manual experience, simultaneously effectively ensuring the preheating efficiency by the real-time feedback control of the preheating process, and effectively avoiding the waste of energy media and strictly executing the baking temperature requirement of refractory materials by the temperature rise control according to the process curve; 2) by adopting the preheating control method, the hit rate of the baking temperature of the tundish exceeds 98%, the average baking time of a single tundish is 118min, the maximum gas consumption is controlled to be less than 450m3/h, the gas consumption of the single tundish is saved by 27%, the precision of a gas regulating valve requires a temperature fluctuation range of 5 degrees, the preheating effect of the tundish is good, and the casting success rate of the continuous casting tundish is ensured to realize 100%.
Drawings
FIG. 1 is a process control flow diagram of the present invention.
The specific implementation mode is as follows:
for the purpose of enhancing an understanding of the present invention, the present embodiment will be described in detail below with reference to the accompanying drawings.
Example 1: referring to fig. 1, a tundish preheating automatic control method based on continuous temperature measurement includes the following steps:
step 1, installing a continuous temperature measuring thermocouple head in a tundish by a three-dimensional positioning method;
and 2, dividing the preheating temperature into four preheating intervals of small fire, medium fire, large fire and heat preservation according to the target preheating temperature (1100-1300 ℃) of the tundish and the preheating time requirement of the tundish. Setting a segmented target temperature interval according to the temperature rise speed of the refractory material of the tundish, and setting the temperature of the target interval and the air excess coefficient of a set air-fuel ratio for the corresponding preheating interval;
step 3, collecting a continuous casting tundish position signal, a preheating ignition device signal and a preheating starting signal;
and 4, when the position signal of the tundish reaches a preheating position, the preheating ignition device is turned on and feeds back that the flow of the preheating medium of the ignition pipeline is more than 10m3/h, the preheating ignition device is successfully turned on, and a preheating starting signal is received, the preheating medium valve is turned on to preheat the tundish. The judgment of the flow of the ignition pipeline can ensure successful ignition, and the preheating explosion phenomenon caused by sudden ignition after the preheating medium is gathered due to long-time non-ignition is avoided;
and 5, executing small-fire preheating interval control, setting 8-12 segmented target temperature intervals, and controlling the temperature rise speed to be less than 50 ℃/min within the set segmented target temperature interval time. Controlling the flow of the preheating medium to be Q1, and controlling the flow to be Q1 within the target range and time of each preset cell if the temperature exceeds Tn + Ta; if the temperature is always less than Tn, the flow rate of the preheating medium is continuously controlled to be Q2. And setting an air excess coefficient of 1.35-1.45 according to a standard air-fuel ratio of the fuel, and controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium. The sectional target temperature interval is set, so that the temperature rise speed can be ensured to be within a controllable range, and the abnormal hidden dangers of cracking and bulging of the refractory material caused by too fast temperature rise during preheating of the tundish are solved. The air excess coefficient is set to be 1.35-1.45, the flame length can reach the bottom of the tundish, and high-temperature baking of the tundish cover is avoided;
and 6, after the preheating time reaches 1/4X, performing intermediate fire preheating interval control, setting 8-12 segmented target temperature intervals, and controlling the temperature rise speed to be less than 20 ℃/min within the set segmented target temperature interval time. Controlling the flow of the preheating medium to Q3, and controlling the flow to Q2 if the temperature exceeds Tn + Ta within a specified time of 1/4X; if the temperature is always less than Tn, continuously controlling the flow of the preheating medium at Q3; and controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium according to the standard air-fuel ratio of the fuel and the air excess coefficient of 1.25-1.35. The sectional target temperature interval is set, so that the temperature rise speed can be ensured to be within a controllable range, an ideal temperature rise effect can be realized at the stage, and constant temperature rise is achieved. The air excess coefficient is set to be 1.25-1.35, so that the full combustion of a preheating medium and the uniform preheating of the tundish wall are ensured;
and 7, after the preheating time reaches 1/2X, executing intense fire preheating interval control, setting 8-12 segmented target temperature intervals, and controlling the temperature rise speed to be less than 15 ℃/min within the set segmented target temperature interval time. : controlling the flow of the preheating medium to Q4, and controlling the flow to Q3 if the temperature exceeds Tn + Ta within a specified time of 1/2X; if the temperature is always less than Tn, the flow rate of the preheating medium is continuously controlled to be Q4. And controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium according to the standard air-fuel ratio of the fuel and the air excess coefficient of 1.25-1.35. The sectional target temperature interval is set, so that constant-speed temperature rise in a specified time can be ensured, and the temperature of the tundish can reach more than 1100 ℃. The air excess coefficient is set to be 1.25-1.35, so that the full combustion of a preheating medium and the uniform preheating of the tundish wall are ensured; (ii) a
And 8, after the preheating time reaches X, executing heat preservation and preheating interval control, and controlling the temperature fluctuation speed to be less than 5 ℃/min. Controlling the flow of the preheating medium to be Q3, and controlling the flow to be Q2 if the temperature exceeds T +10 degrees in the time before the preheating is stopped; if the temperature is always less than T, the flow of the preheating medium is continuously controlled to be Q4; controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium according to the standard air-fuel ratio of the adopted fuel and the air excess coefficient of 1.20-1.25;
and 9, receiving a preheating end signal, and ending the automatic preheating process.
Wherein, in the step 1, the three-dimensional positioning method is to install a continuous temperature measuring couple head in the tundish, and the method comprises the following specific steps:
1.1, positioning the thermocouple installation position at a position which is vertically 300mm-400mm away from the bottom of the tundish (Y-axis direction) and is vertically 600mm-800mm away from the side edge of the tundish (Z-axis direction);
1.2 the installation extension length of the thermocouple position is controlled to be 160mm-180mm (X-axis direction).
The installation method and the distance setting can ensure that the installation position and the extension length of the continuous temperature thermocouple in the tundish are fully ensured, so that the temperature of the inner cavity of the tundish can be accurately measured in the preheating time, the temperature of the outer flame of the baking flame is not measured, and the temperature measurement error can be controlled within +/-5 ℃.
Step 2, setting target interval temperature in different time intervals according to the target temperature and the preheating time requirement of the tundish, wherein the target interval temperature is specifically as follows:
2.1 setting a target preheating temperature T and a target preheating time X;
2.2 setting the preheating target temperature, preheating time and upper and lower limits of the preheating energy medium in different stages according to the target preheating temperature T and the target preheating time X and according to the small fire stage, the medium fire stage, the large fire stage and the heat preservation stage; the preheating interval method can ensure the preheating temperature rise speed of the tundish within the specified time, and the baking temperature rise speed is controlled to be 15-60 ℃/min according to the current refractory material requirement, so that the refractory material can not crack. The preheating interval and the corresponding preheating target temperature set in the step can accurately control the baking temperature rise speed to be 45-50 ℃/min, and the stability of the preheated refractory material is improved.
2.3 setting and defining a temperature rise curve of each preheating interval according to the regulation and control precision of the energy medium valve and 8-12 time periods with target rise temperature Tn which are equally divided according to the target temperature interval and the preheating time;
2.4 setting a fluctuation range Ta (4-8 ℃) for the target temperature among the N small regions, and avoiding frequent adjustment of the valve; the innovative setting of the fluctuation range can avoid frequent actions of the medium regulating valve and ensure the service life and the period of the valve. By setting the fluctuation range, the valve action frequency can be reduced by 35 percent, and the service life of the valve is prolonged by 120 days.
The specific application embodiment is as follows: referring to fig. 1:
in this case, the on-site tundish has the function of thermocouple on-line continuous temperature measurement. Preheating the tundish by adopting a gas preheating mode, wherein the maximum flow of the specified gas cannot exceed 500m3/h, the minimum flow cannot be lower than 200m3/h, the preheating temperature of the tundish required by field process control cannot be lower than 1250 ℃, and the normal preheating time is 120 min. And controlling according to the method, and preheating by adopting a continuous temperature measurement-based tundish preheating automatic control method.
A tundish preheating automatic control method based on continuous temperature measurement comprises the following steps:
step 1, installing a continuous temperature measuring couple head in a tundish by a three-dimensional positioning method.
1.1, positioning the thermocouple mounting position at a position which is vertically 350mm away from the bottom of the tundish (Y-axis direction) and is vertically 700mm away from the side edge of the tundish (Z-axis direction);
1.2 thermocouple position installation extension length is more than 170mm (X axis direction)
And 2, dividing the preheating temperature into four preheating intervals of small fire, medium fire, large fire and heat preservation according to the target preheating temperature (1100-1300 ℃) of the tundish and the preheating time requirement of the tundish. Setting a segmented target temperature interval according to the temperature rise speed of the refractory material of the tundish, and setting the temperature of the target interval and the air excess coefficient of a set air-fuel ratio for the corresponding preheating interval; .
2.1 setting the target preheating temperature to 1250 ℃ and the target preheating time to 120 min;
2.2 setting the preheating target temperature, the preheating time and the upper and lower limits of the preheating energy medium in different stages according to the target preheating temperature 1250 ℃ and the target preheating time 120min and according to the small fire stage, the medium fire stage, the large fire stage and the heat preservation stage;
2.3 in each preheating interval, according to the regulation and control precision of the energy medium valve, according to the target temperature interval, preheating time and the like,
according to the accuracy of the gas regulating valve, each preheating interval is divided into 10 time periods with target lifting temperature,
2.4 setting the fluctuation range Ta to be +/-5 for the target temperature among 10 cells, and avoiding frequent adjustment of the valve;
the method comprises the following specific steps:
| preheating interval | Preheating time | Time period N setting | Target elevated temperature (degree centigrade) |
| Small fire | 30mim | 10 | 60±5 |
| Middle fire | 30min | 10 | 37.5±5 |
| Big fire | 60min | 10 | 25±5 |
Step 3, acquiring a continuous casting tundish position signal, a preheating ignition device signal and a preheating starting signal;
step 4, when the position signal of the tundish reaches a preheating position, the preheating ignition device is turned on and feeds back that the flow of the preheating medium of the ignition pipeline is more than 10m3/h, the preheating ignition device is successfully turned on, and a preheating starting signal is received, the preheating medium valve is turned on to preheat the tundish;
step 5, small fire preheating interval control is executed, the gas flow is controlled to 200m3/h, and if the temperature rises to be more than 60 +/-5 ℃ within 3min, the flow is controlled to 200m 3/h; and if the temperature rise is always less than 60 +/-5 ℃, continuously controlling the gas flow at 250m 3/h. Setting the air excess coefficient of the air-fuel ratio of the coal gas to be 1.4;
and 6, after the preheating time reaches 30min, executing intermediate fire preheating interval control: controlling the gas flow to 350m3/h, and controlling the gas flow to 250m3/h within 3min if the temperature rises to be over 37.5 +/-5 ℃; if the temperature rise is always less than 37.5 degrees, the gas flow is continuously controlled at 350m 3/h. Setting the air excess coefficient of the air-fuel ratio of the coal gas to be 1.3;
and 7, after the preheating time reaches 60min, executing the control of the large-fire preheating interval: controlling the gas flow to be 450m3/h, and controlling the gas flow to be 350m3/h within 3min if the temperature is increased to be more than 25 +/-5 ℃; if the temperature is increased to be less than 25 +/-5 ℃, continuously controlling the gas flow to be 450m3/h, and setting the air-fuel ratio air excess coefficient to be 1.2 ℃;
and 8, after the preheating time reaches 120min, executing heat preservation and preheating interval control: the gas flow is controlled to be 250m3/h, and if the temperature exceeds 1250+10 degrees in the time before the preheating is stopped, the gas flow is controlled to be 350m 3/h; if the temperature is always less than 1250 deg.f, the flow rate of the preheated medium is continuously controlled at 450m 3/h. Setting the air excess coefficient of the air-fuel ratio of the coal gas to be 1.2;
and 9, receiving a preheating end signal, and ending the automatic preheating process.
It should be noted that the above-mentioned embodiments are not intended to limit the scope of the present invention, and all equivalent modifications and substitutions based on the above-mentioned technical solutions are within the scope of the present invention as defined in the claims.
Claims (3)
1. A tundish preheating automatic control method based on continuous temperature measurement is characterized by comprising the following steps:
step 1, installing a continuous temperature measuring thermocouple head in a tundish by a three-dimensional positioning method;
step 2, dividing the intermediate ladle into four preheating intervals of small fire, medium fire, large fire and heat preservation according to the target intermediate ladle preheating temperature (1100-1300 ℃) and the intermediate ladle preheating time requirement, setting a subsection target temperature interval according to the intermediate ladle refractory temperature rise speed, and setting the target interval temperature and the air excess coefficient of the set air-fuel ratio for the corresponding preheating interval;
step 3, collecting a position signal of a continuous casting tundish car, a preheating ignition device signal and a preheating starting signal;
step 4, when the position signal of the tundish reaches a preheating position, the preheating ignition device is turned on and feeds back that the flow of the preheating medium of the ignition pipeline is more than 10m3/h, and when a preheating starting signal is received, a preheating medium valve is turned on to preheat the tundish;
and 5, executing small-fire preheating interval control, setting 8-12 segmented target temperature intervals, and controlling the temperature rise speed to be less than 50 ℃/min within the set segmented target temperature interval time. Controlling the flow of the preheating medium to be Q1, and controlling the flow to be Q1 if the temperature exceeds Tn + Ta; if the temperature is always less than Tn, the flow rate of the preheating medium is continuously controlled to be Q2. Setting an air excess coefficient of 1.35-1.45 according to a standard air-fuel ratio of fuel, and controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium;
step 6, after the preheating time reaches 1/4X, executing intermediate fire preheating interval control, setting 8-12 segmented target temperature intervals, controlling the temperature rise speed to be less than 20 ℃/min within the set segmented target temperature interval time, controlling the flow of the preheating medium to be Q3, and controlling the flow to be Q2 within the specified 1/4X time if the temperature exceeds Tn + Ta; if the temperature is always less than Tn, continuously controlling the flow of the preheating medium at Q3; setting an air excess coefficient of 1.25-1.35 according to a standard air-fuel ratio of fuel, and controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium;
and 7, after the preheating time reaches 1/2X, executing intense fire preheating interval control, setting 8-12 segmented target temperature intervals, and controlling the temperature rise speed to be less than 15 ℃/min within the set segmented target temperature interval time. : controlling the flow of the preheating medium to Q4, and controlling the flow to Q3 if the temperature exceeds Tn + Ta within a specified time of 1/2X; if the temperature is always less than Tn, continuously controlling the flow of the preheating medium at Q4; setting an air excess coefficient of 1.25-1.35 according to a standard air-fuel ratio of fuel, and controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium;
and 8, after the preheating time reaches X, executing heat preservation and preheating interval control, and controlling the temperature fluctuation speed to be less than 5 ℃/min: controlling the flow of the preheating medium to be Q3, and controlling the flow to be Q2 if the temperature exceeds T +10 degrees in the time before the preheating is stopped; if the temperature is always less than T, the flow of the preheating medium is continuously controlled to be Q4; setting an air excess coefficient of 1.20-1.25 according to a standard air-fuel ratio of fuel, and controlling the flow rate of the preheating air on the corresponding flow rate of the preheating medium;
and 9, receiving a preheating end signal, and ending the automatic preheating process.
2. The tundish preheating automatic control method based on continuous temperature measurement according to claim 1, wherein the continuous temperature measurement thermocouple is installed in the tundish in the step 1 and the three-dimensional positioning method, and the method comprises the following specific steps:
1.1, positioning the thermocouple installation position at a position which is vertically 300mm-400mm away from the bottom of the tundish (Y-axis direction) and is vertically 600mm-800mm away from the side edge of the tundish (Z-axis direction);
1.2 the installation extension length of the thermocouple position is controlled to be 160mm-180mm (X-axis direction).
3. The automatic tundish preheating control method based on continuous temperature measurement according to claim 2, wherein the step 2 is divided into four preheating intervals of small fire, medium fire, large fire and heat preservation according to the target tundish preheating temperature (1100 ℃ -1300 ℃) and the preheating time requirement of the tundish. According to the temperature rise speed of the refractory material of the tundish, setting a subsection target temperature interval, and setting the temperature of the target interval and the air excess coefficient of the set air-fuel ratio for the corresponding preheating interval, wherein the specific steps are as follows:
2.1 setting a target preheating temperature T, a target preheating time X and an air-fuel ratio excess air coefficient;
2.2 setting the preheating target temperature, preheating time and upper and lower limits of the preheating energy medium in different stages according to the target preheating temperature T and the target preheating time X and according to the small fire stage, the medium fire stage, the large fire stage and the heat preservation stage; the preheating interval method can ensure the preheating heating rate of the tundish within the specified time, and the baking heating rate is controlled to be 15-60 ℃/min according to the current refractory material requirement, so that the refractory material can not crack;
2.3 setting and defining a temperature rise curve of each preheating interval according to the regulation and control precision of the energy medium valve and 8-12 time periods with target rise temperature Tn which are equally divided according to the target temperature interval and the preheating time;
2.4 setting a fluctuation range Ta (4-8 ℃) for the target temperature between 8 and 12 cells, and avoiding frequent adjustment of the valve.
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