JPH0610056A - Method and device for controlling temperature of strip material in heatiang furnace - Google Patents

Abstract

PURPOSE:To stabilize the control of strip temp. in a heating furnace and to improve the control accuracy by controlling manipulated variables such as fuel flow rate based the estimated value without depending the measured value in the strip temp. at an outlet on to a prescribed section at the front part and the rear part of the connecting part of the different kinds of the strip-like material. CONSTITUTION:In the heatiang furnace 21 for heat-treating the steel strip, the strip temp. at the outlet is measured with radiation temp. through a strip temp. meter 22. Based on the information of the actual values including the measured value and the aimed strip temp., material of the steel strip, strip passing speed, etc., by controlling the fuel flow rate and the other operating quantity setting to the heating furnace 21 in an optimum strip temp. control part 23, the furnace temp. is adjusted. In the strip temp. control method in the heating furnace, in the case of connecting the different kinds of the steel strip drawn out from pay-off reels 26a, 26b in an automatic welding mechanism 24 and continuously passing into the heatiang furnace 21, the position of the connecting part is detected by the steel strip connecting part positioning observation part 25. At the time of executing heat treatment in the vicinity of the connecting part calculated from the strip passing speed, the measured value of the strip temp. at the outlet is made to be invalid and the estimated value is used instead of the above value, or the manipulated variables are fixed at the front and the rear parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating furnace plate temperature control method and apparatus for a plate-like body used for annealing a steel plate or a thin steel strip.

[0002]

2. Description of the Related Art As an annealing device for steel sheets after cold rolling, heating furnaces, soaking furnaces and cooling furnaces arranged in series along a transport path are continuously connected while connecting different kinds of steel sheets by automatic welding. The continuous annealing treatment device that is passed through is in operation. In such a continuous annealing treatment device, in order to ensure the quality of the steel sheet after the annealing treatment and avoid operating troubles such as heat buckles, it is important to control the temperature of the steel sheet called "sheet temperature". In particular, stabilization of plate temperature control and improvement of accuracy in heating furnaces are important issues.

In the above continuous annealing apparatus, a stepwise change (“set change”) such as a width of a steel sheet (“sheet width”) or a thickness of a steel sheet (“sheet thickness”) occurs at a joint portion of different steel sheets. However, in order to execute the plate temperature control under the occurrence of such a set change and the high transport speed (“passing speed”) reaching several tens to several hundreds of meters per minute, a considerably high technology is required. Is required.

The plate temperature control in the heating furnace uses the plate temperature at the outlet of the heating furnace (“outlet plate temperature”), the furnace temperature, etc. as actual values, and the flow rate or heating of the fuel such as coke gas to be supplied to the heating furnace. It is performed by a closed-loop type optimum plate temperature control device in which the furnace temperature to be set in the furnace is an operation amount. For this reason, how to measure the outlet plate temperature with high accuracy is the key to determining the success or failure of the optimal plate temperature control.However, because the steel plates are transported while corrugated, this measurement of the outlet plate temperature is a non-contact type radiation. I have to rely on a thermometer. Conventionally, regarding the measured value of the outlet plate temperature by the radiation thermometer, the measured temperature is corrected for each type of steel sheet in consideration of the difference in emissivity due to the material of the steel sheet and the like.

[0005]

The present inventor has found that the measured value of the outlet plate temperature by the radiation thermometer shows an abnormal value over a long section ranging from several tens of meters to several hundreds of meters before and after the joint of the steel plates by welding. Confirmation was confirmed by data analysis. That is, as shown in FIG. 4, when the measured values of the plate thermometer are monitored under the condition that the plate temperature fluctuation factors such as the strip running speed and the fuel flow rate are constant, the number of steel plates before and after the connecting portion It was confirmed that the measured value showed an abnormal value over a section of about 10 m to 100 m.

Since the connecting portion of the steel plates corresponds to the end of each steel plate, the quality of the end differs from the quality of the central part in the pre-treatment such as cold rolling, and as a result, the emissivity differs from that of the central part. Is also considered to be different. The cause of this is unknown at this point, but it was confirmed that the measured values around the joint show abnormal values in various patterns.
Therefore, an object of the present invention is to further stabilize the optimum plate temperature control and improve the control accuracy by reflecting the above new knowledge in the optimum plate temperature control.

[0007]

A heating furnace plate temperature control method and apparatus for a plate-shaped body according to the present invention receives production information including a measured value of an outlet plate temperature and a target value of the outlet plate temperature. The optimum plate temperature control means (process) for controlling the fuel flow rate and other manipulated variables set in the heating furnace (process) and the means (process) for monitoring the position of the connecting portion of the plate-like body during conveyance are provided. The control means (processing) includes means (processing) for invalidating the received measured value of the outlet plate temperature for a predetermined section before and after the connecting portion of the plate-shaped body.

[0008]

In other words, according to the heating furnace plate temperature control method and apparatus of the present invention, as shown in FIG. 4, for a predetermined section (δL1 + δL2) centered on the connecting portion of the steel plates, the outlet plate temperature measured by the radiation thermometer is used. The measured value of is invalidated and the fuel flow rate is maintained at the previous value. Alternatively, the optimum plate temperature control process is performed using the estimated value instead of the invalidated outlet plate temperature. In any case, the instability of control and the decrease in accuracy due to the incorporation of an erroneous measurement value into the control loop due to the variation of the emissivity in the vicinity of the coupling portion are effectively avoided.

FIG. 3 is a functional block diagram showing the configuration of a heating furnace plate temperature control apparatus to which the heating furnace plate temperature control method for a plate-shaped body according to an embodiment of the present invention is applied.
Is a plate thermometer, 23 is an optimum plate temperature control unit, 24 is an automatic welding unit,
Reference numeral 25 is a steel plate connecting portion position monitoring portion, and 26a and 26b are payoff reels.

The dissimilar steel plates wound around the pay-off reels 26a and 26b are continuously connected to each other in a predetermined order by automatic welding in the automatic welding section 24 while being continuously heated by a transfer mechanism including a take-up reel (not shown). It is transported to the inside of the furnace while being heated. Heating furnace 2
At the outlet side of 1, the plate thermometer 22 by a non-contact type radiation thermometer
Is installed, and the measured value of the outlet plate temperature is supplied to the optimum plate temperature control unit 23 as one of the actual values. The furnace temperature measured by a thermometer installed in the heating furnace 21 is also supplied to the optimum plate temperature control unit 23 as one of the actual values.

The steel plate connecting portion position monitoring unit 25 notifies the completion of the automatic welding received from the automatic welding unit 24, the plate passing speed sent from an electric equipment controller (not shown), and the welding installed on the steel sheet conveying path (not shown). The current position of the joint of the steel plates is calculated from the signal of the point passage detector and the like, and the optimum plate temperature control unit 23 is notified.

The optimum plate temperature control unit 23 measures the measured value of the outlet plate temperature input from the plate thermometer 22 and the measured value of the furnace temperature input from the heating furnace 21, the target plate temperature, the plate width, the plate thickness, While receiving the production information including the strip running speed and the like, and based on the current position of the joint notified from the steel plate joint position monitoring unit 25, calculate the fuel flow rate to be set in the heating furnace 21 according to a predetermined algorithm, The operation amount is output to the heating furnace 21.

FIG. 1 is a flow chart for explaining an example of the fuel flow rate calculation and setting process by the optimum plate temperature control unit 23. This process is realized by a program executed on an electronic computer, and is activated when the strip running speed changes, and is also activated periodically by a timer or the like. First, the measured value of the outlet plate temperature being output by the plate thermometer 22 and the measured value of the furnace temperature being output by the heating furnace 21 are read (step 11). Then, the current position of the steel plate connecting portion notified from the steel plate connecting portion position monitoring unit 25 is read (step 12), and the read current position of the steel plate connecting portion is away from the plate thermometer 21 by a predetermined value or more. It is determined whether or not there is any (step 13).

If the current position of the connecting portion of the steel plates is located at a distance of a predetermined value or more from the plate thermometer 21, the measured value of the outlet plate temperature is updated by the value read in step 11 (step 1
4) Based on the updated measured value and the plate temperature model, the fuel flow rate to be set in the heating furnace 21 is calculated (step 15). In the calculation process of the fuel flow rate in step 15, the “plate temperature model” that predicts the outlet plate temperature from the production information and the operation record, and the measured values of the outlet plate temperature and the furnace temperature are taken as actual values, and the outlet plate temperature And a process for calculating a fuel flow rate for making the measured value approach the target plate temperature trajectory calculated using the plate temperature model. Regarding the calculation process of the fuel flow rate using this plate temperature model, the specification of Japanese Patent Application Laid-Open No. 61-190026 related to the prior application of the present applicant and "Measurement and Control" Vol. 25, No. 11 (Showa 61 1
January), "Continuous annealing treatment equipment (C.A.P.
See, for example, the paper by Yoshiya entitled "L) Optimum Plate Temperature Control Method for Heating Furnace".

On the other hand, the current position of the connecting portion of the steel plates and the plate thermometer 2
When it is determined in step 13 that the distance to 1 is less than the predetermined value, the measured value of the outlet plate temperature is replaced with the estimated value of the outlet plate temperature calculated in advance (step 17), and then the step At 14, the measured value of the replaced outlet plate temperature is updated. That is, the outlet plate temperature measured by the plate thermometer 22 is discarded, and instead of the discarded measured value of the outlet plate temperature, the estimated value of the outlet plate temperature of the previously calculated outlet plate temperature is calculated in step 15 this time. Used for calculation processing.

FIG. 2 is a flow chart for explaining another example of the fuel flow rate calculation and setting process by the optimum plate temperature control unit 23. The steps in FIG. 2 designated by the same reference numerals as those in FIG. 1 are the same as the corresponding steps already described with reference to FIG. 1, and duplicate description of these steps will be omitted. That is, the process of FIG. 2 differs from the process of FIG. 1 only in the case where the connecting portion of the steel plates comes close to the plate thermometer within a predetermined range. In this case, in step 18, the previously set fuel flow rate is set as it is in the heating furnace, and the process ends.

[0017]

As described in detail above, the heating furnace plate temperature control apparatus and method according to the present invention has a new method in which the measured value of the radiation thermometer shows an abnormal value over the sections before and after the connecting portion of the steel plates. Based on the knowledge, the measurement value is invalidated for this section, so that it is possible to reliably achieve the stabilization and the high accuracy of the control.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining an example of a fuel flow rate calculation and setting process by an optimum plate temperature control unit 23 in FIG.

FIG. 2 is a flowchart for explaining another example of the calculation and setting process of the fuel flow rate by the optimum plate temperature control unit 23 of FIG.

FIG. 3 is a functional block diagram showing a configuration of a heating furnace plate temperature control apparatus to which the heating furnace plate temperature control method of one embodiment of the present invention is applied.

FIG. 4 is a conceptual diagram for explaining a phenomenon in which a measured value of an outlet plate temperature by a radiation thermometer shows an abnormal value before and after a connecting portion of steel plates.

[Explanation of symbols]

 21 Heating Furnace 22 Radiation Thermometer 23 Optimum Plate Temperature Control Unit 24 Automatic Welding Mechanism 25 Steel Plate Connection Position Monitoring Unit

Claims (4)

[Claims] 1. A heating furnace is arranged in a transfer path of a series of plate-like bodies connected via a connecting portion, and the heating of the plate-like bodies is controlled by controlling the heating furnace. A method for controlling a temperature, comprising a process of obtaining a measurement value by measuring a temperature (referred to as “exit plate temperature”) of the plate-shaped body carried out from the heating furnace by a radiation temperature, and the exit plate. Optimal plate temperature control processing for receiving the production information including the actual value including the measured value of the temperature and the target value of the plate temperature and controlling the fuel flow rate and other manipulated variables to be set in the heating furnace, and the plate-shaped member being conveyed. And a process of monitoring the position of the connecting portion, the optimal plate temperature control process, the predetermined value before and after the connecting portion of the plate-like body replaces the measured value of the received outlet plate temperature with its estimated value. Heating furnace plate temperature control method for a plate-shaped body, characterized in that 2. The optimum plate temperature control process according to claim 1, wherein the optimum plate temperature control process includes a process of invalidating the measured value of the outlet plate temperature and fixing the manipulated variable during the invalid period. Method for controlling plate temperature of plate-shaped heating furnace. 3. A heating furnace is arranged in a transfer path of a series of plate-like bodies connected via a connecting portion, and the heating of the plate-like body is controlled by controlling the heating furnace. An apparatus for controlling the temperature, which measures the temperature of the plate-shaped body carried out from the heating furnace (referred to as “exit plate temperature”) by radiant energy to obtain a measured value, and the exit plate. Optimal plate temperature control means for receiving the production information including the actual value including the measured value of the temperature and the target value of the plate temperature and controlling the fuel flow rate and other manipulated variables set in the heating furnace; And a means for monitoring the position of the connecting portion, the optimum plate temperature control means replaces the measured value of the received outlet plate temperature with its estimated value for a predetermined section before and after the connecting portion of the plate-shaped body. Heating means for heating a plate-like body characterized by comprising means for Control device. 4. The optimum plate temperature control means according to claim 3, further comprising means for invalidating the measured value of the outlet plate temperature and fixing the manipulated variable during the invalid period. A plate heating control device for a plate-shaped heating furnace.