JPH0332605B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heating control method in a continuous heating furnace.

(Prior art) As a control method for continuous heating furnaces, the expected temperature drop from heating furnace extraction to rolling is added to the rolling target temperature for each material to determine the heating target temperature, and the temperature is calculated based on the temperature at the time of cutting in the continuous casting equipment. Determine the temperature of the material at the time of charging into the heating furnace by thermal calculation or by correcting it with a charging thermometer, and using this as an initial value, determine the material heating temperature in the heating furnace by heat transfer calculation from the ambient temperature or furnace wall temperature, The moving speed of the material in the furnace is predicted from the extraction pitch given by the operation policy, and at the time of extraction, the heating temperature of the material is kept at the minimum target heating temperature, and at the time of rolling, the rolling temperature of the material is set to the target rolling temperature. Heating is controlled to ensure a minimum amount of heat.

Conventionally, in the above-mentioned heating control method, an in-furnace material thermometer is generally used to detect errors in material temperature calculation at charging and/or temperature rise calculation in the heating furnace. In order to provide feedback to the heating including the drop prediction error,
The amount of deviation between the actually measured temperature in the rolling line and the rolling target temperature has been fed back as a correction amount for the heating target temperature.

(Problems to be Solved by the Invention) However, when measuring with a furnace material thermometer, it is not possible to completely seal disturbance radiant energy from the furnace wall or flame, and furthermore, the equipment for sealing is large-scale. However, there were problems with accuracy, durability, equipment costs, etc.

In addition, the method of feeding back the amount of deviation between the measured temperature on the rolling line and the rolling target temperature is such that due to the limitations of the heating device consisting of a heating zone, the rolling target temperature and the actual rolling temperature, which differ for each material, constantly match. There was also a problem in feeding back the amount of deviation. To explain in more detail, as shown in FIG. 2a, the rolling target temperature for each material is not uniform due to constraints on the rolling schedule, etc., but varies in steps over time. In order to maintain this rolling target temperature at a minimum, due to the nature of the heating device consisting of a heating zone, there will inevitably be overheated material. Since the amount of fuel is large, heating may be insufficient, which may lead to a line stoppage. Further, since a large feedback gain cannot be achieved, there is also the problem that it is not necessarily effective as feedback for detecting various errors.

Therefore, the purpose of the present invention is to eliminate the need for the furnace material thermometer, which conventionally involved various problems, and to
It is an object of the present invention to provide a heating control method in a continuous heating furnace that accurately detects and feeds back errors including both in-furnace temperature increase heat transfer calculation errors and temperature drop errors, and ensures a minimum rolling target temperature.

(Means for solving the problems) In order to solve the above problems, the present invention provides the first
As shown in the figure, the predicted temperature drop from heating furnace 1 extraction to rolling is added to the rolling target temperature for each material M to determine the heating target temperature, and this heating target temperature is set at the cutting point in the continuous casting equipment. Based on the material heating temperature in the heating furnace, which is calculated from the furnace wall temperature or the ambient temperature, based on the material temperature at charging, which is calculated from the temperature by heat transfer calculation or by correcting it with a charging thermometer. In addition, the error temperature between the calculated actual temperature drop and the predicted temperature drop from the calculated heating temperature at the time of extraction in the heating furnace to the actual measured temperature at the time of rolling is determined to be the target heating temperature of the material existing in the furnace. It is characterized by correcting errors including both the temperature rise heat transfer calculation error in the furnace and the predicted temperature drop calculation error by feeding back to the heating as a correction amount and ensuring the rolling target temperature to the minimum. It is.

That is, the present invention provides the calculated actual temperature drop from the calculated heating temperature at the time of extraction to the actual temperature measured during rolling by the hot steel thermometer 3 provided in the rolling mill 2, and the predicted temperature drop when determining the heating target temperature. By detecting the error temperature of the material, it is possible to accurately detect errors in material temperature calculation at charging, heating furnace temperature rise calculation, and rolling line temperature drop prediction calculation without using a furnace material thermometer. This makes it possible to provide feedback to the heating target temperature and to ensure the minimum rolling target temperature for each material.

The formula for calculating the amount of feedback is shown below.

TH=TM+TDE (1) TDA=THC−TMA (2) εTD=TDA−TDE (3) Where, TM: Rolling target temperature TDE: Predicted temperature drop (slab size, rolling size, rolling time, descaling planned heating assumption) (Determined from temperature, etc.) TH: Target heating temperature THC: Calculated heating temperature during extraction TMA: Actual measured temperature on the rolling line TDA: Calculated actual measured temperature drop εTD: Error detection temperature (Charging temperature calculation error Material temperature rise calculation error Predicted temperature (including calculation error) TOF'=K・1/n _o 〓 ⁱ⁼¹ (εTDi) (4) or TOF'=TOF"+K [εTD-TOF"] (5) TOF': Feedback amount (heating target temperature) TOF'': Feedback amount of previous material K: Feedback gain The error temperature for each material is detected using equations (1) to (3), and the moving average of equation (4) or the primary delay filter of equation (5) is applied to multiple If there is a furnace, it is calculated for each furnace and determined as the heating target temperature feedback amount called TOF'.

This feedback amount is given a coefficient according to the position of each material in the relevant furnace, and is added to the material heating target temperature to set each final heating target temperature and combustion control is performed.

(Effects of the Invention) FIG. 2 shows the effects of the present invention in comparison with the prior art. a indicates the prior art and b indicates the present invention.

In the conventional technology, when the target rolling temperature changes in a stepwise manner, the follow-up is slow and the amount of overshoot is large, resulting in insufficient heating. Also, it is not possible to increase the feedback gain.

In contrast, with the present invention, it is possible to correct errors including temperature rise calculations and temperature drop calculations, regardless of stepwise changes in the rolling target temperature, and there is no underheating, and the rolling target temperature can be minimized. can be secured.
Further, a large feedback gain can be achieved. Specifically, the amount by which the rolling temperature exceeded the rolling target temperature could be reduced by 3° C., resulting in an energy saving effect.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the control method of the present invention, Figure 2 is a schematic diagram showing the control method of the present invention;
The figures show the effects of the present invention in comparison with the prior art, where a is the prior art and b is the present invention. M...Material, 1...Heating furnace, 2...Rolling machine, 3
...Heat steel thermometer.

Claims (1)

[Claims] 1 The heating target temperature is obtained by adding the predicted temperature drop from heating furnace extraction to rolling to the rolling target temperature for each material, and this heating target temperature is the heating value determined by heat transfer calculation from the ambient temperature or furnace wall temperature. In addition to ensuring the minimum temperature based on the material heating temperature in the furnace, the error temperature between the calculated actual temperature drop and the predicted temperature drop from the calculated heating temperature at the time of extraction in the furnace to the actual measured temperature at the time of rolling is By feeding back to heating as a correction amount for the heating target temperature of the material existing in A heating control method characterized by ensuring that.