JPH01198431A - Furnace temperature setter for continuous heating furnace - Google Patents

Abstract

PURPOSE:To provide the title furnace temp. setter which is capable of controlling temp. with high accuracy without overheating and insufficient heating even if ingots of different burned states coexist in a control zone by constituting the setter in such a manner as to select an optimum computation method according to the distribution state of the target temp. of the ingots and to compute a furnace set temp. CONSTITUTION:The ingots inserted into the continuous heating furnace 1 are heated respectively in different forms in a preheating zone, heating zone and holding zone and are then successively ejected 2. The furnace temps. in the upper and lower parts of the holding zone are detected 3 at this time and the furnace temps. are independently controlled 4 when the furnace temp. setter 10 sets the optimum furnace temp. in accordance with the detected values. The material data such as the size and material quality of the ingots and the process data such as ejection temp. are inputted by an input means 11 and are stored 12 for the purpose of said furnace temp. setting. An ejection signal is applied to an ejection pitch computing means 13 and a temp. computing means 15 at every ejection of the ingots from the furnace 1. The means 13 of the above-mentioned means computes the intended ejection pitch till the specified time by the stored 12 process data.

Description

[Detailed Description of the Invention] [Structure of the Invention] (Field of Industrial Application) The present invention relates to a continuous heating furnace for heating a material to be heated (hereinafter referred to as a steel billet) such as a slab or billet, and in particular,
The present invention relates to a furnace temperature setting device that calculates a furnace temperature setting value to be matched with a furnace temperature detection value in a control zone when controlling the calorific value.

(Prior Art) KonoMori's conventional continuous heating furnace is a rear zone type continuous heating furnace that has three control zones: a preheating zone, a heating zone, and a soaking zone.

This rear zone continuous heating furnace has a burner that injects and burns fuel in each control zone, a furnace temperature sensor that detects the furnace temperature, and a furnace temperature value detected by this furnace temperature sensor and a furnace temperature setting device. It has a control device that controls g set so that the deviation of the furnace temperature set value (θ, ) approached zero, and is configured to be able to independently control the temperature in each control band.

Then, the steel slab is heated while sequentially moving through a pre-heating zone, a heating zone, and a soaking zone, and is baked at the extraction port so as to reach the extraction target temperature. By the way, there are usually multiple pieces of steel in these control zones, and there are cases where there are pieces of steel with the same dimensions, material, extraction target temperature, surface temperature limit value, etc., and there are cases where there are pieces of steel with different values. There are cases where it is done.

Among these, if there are steel slabs with the same dimensions, material, extraction target temperature, surface temperature limit value, etc., the time delay until the furnace temperature is controlled to the set value is not taken into consideration to bring the steel slabs to the extraction target temperature. Sometimes it is not possible to bake.

On the other hand, if the dimensions, material, extraction target temperature, surface temperature limit value, etc. of the steel slabs are different, the furnace temperature must be reset every time a steel slab is extracted, and if the settings are not appropriate, It may not be possible to heat the steel pieces in the furnace to the target extraction temperature, or the steel pieces may be overheated during extraction.

Therefore, conventionally, the furnace temperature was set using one of the following two methods.

(a) Among the steel pieces mixed in the control zone, the furnace temperature is set so that the extraction target temperature can be reached when this steel piece is extracted, paying attention to the steel piece that is least fired.

(b) For each piece of steel mixed in the control zone,
The extraction temperature at the scheduled extraction time is estimated, and each billet is heated in the furnace from the current time until it is extracted, so as to minimize the sum of the deviations between this estimated extraction temperature value and the extraction target temperature, or the sum of the squares of the temperature deviations. Set the temperature.

(Issue 8 to be solved by the invention) Of the two furnace temperature setting methods mentioned above, if method (a) is adopted, if there is a steel billet that is extremely under-hardened compared to the others, this There was a lag point where many of the billets preceding and following the billet were baked well above the extraction target temperature.

In addition, if the method shown in (b) is adopted, the average furnace temperature setting value will be calculated by paying attention to all the slabs existing in the same control zone, and the slab that is most under-hardened will be calculated. The extraction temperature may be considerably lower than the extraction target temperature. If this temperature becomes lower than the allowable extraction temperature for rolling, for example, the extraction must be delayed until the material is heated to the allowable extraction temperature for rolling, resulting in what is called a waiting period for the heating furnace. There was also the problem that the rolling schedule would be significantly changed if this waiting time for the heating furnace occurred.

This invention was made to solve the above-mentioned problems, and even when steel slabs with different fired states coexist in the control zone, it is possible to perform high-precision temperature control without overheating or underheating. The purpose of this invention is to obtain a furnace temperature setting device for a continuous heating furnace. - [Structure of the Invention] (Means for Solving the Problems) A furnace temperature setting device for a continuous heating furnace according to the present invention includes an input means for inputting material data and process data of a material to be heated, and a memory for storing these data. and a memory for storing estimated temperature data, a position calculation means for calculating the future position of the heated material in the control zone, and a temperature for calculating the current temperature of each heated material and sequentially updating the estimated temperature data in the memory. a calculation means, a target temperature curve indexing means for indexing the optimum target temperature corresponding to the stored content of the memory and the calculated future position for each material to be heated, and storing the target temperature, the future position of the material to be heated, and the memory in the memory. an optimal furnace temperature set value calculation method selection means for selecting the optimal one from a plurality of furnace temperature set value calculation methods including weighted averaging, based on the calculated data, and an optimal weight for selecting an optimal weighting coefficient. According to the coefficient calculation means and the selected optimum furnace temperature set value calculation method,
and an optimum furnace temperature setting value calculating means for calculating the furnace temperature setting value of the control zone using the optimum weighting coefficient as necessary.

(Function) As shown in FIG. 2, the steel piece S existing in one control zone of the heating furnace is at time t. At position X. is in the furnace at time t1
Suppose that the user moves to position X1 at . This steel piece S has a target value of the material average temperature at each position in the direction toward the extraction port, and the series of these target values is the target temperature curve A.
It has become.

Twenty-two, position X. The target temperature at T. , if the target temperature at position X1 is T1, then the steel piece S is at position X. The current temperature θ within the time Δt (−1, −18) to move from to position X1. It is necessary to raise the temperature from the target temperature Tl. The furnace temperature θ required to raise the temperature by this temperature difference Δθ (-T1-θ) can be calculated by the following equation using the surface temperature of the material.

-273...Song (1) Where, C: Specific heat (Kcal/Kg ``C) ρ: Density (Kg/Td) b: Width of steel slab (m) σ: Stefan-Bormann constant ΦCGu ' Upper overall heat absorption Rate Φ..1: Lower overall heat absorption rate Δθ: Temperature deviation (-T1-θo) (''C) Δ: Time interval (-tl-to) (hr) θ: Furnace temperature ('C) θ: Steel slab Upper surface temperature ('C) θl : Lower surface temperature ('C) of the steel piece.

On the other hand, in one control zone of the heating furnace, as shown in FIG. 3, n steel pieces s1. s2. s3.・.

Positions X where S, -1, and Sn are respectively distant from the extraction port in order
, XX ..., X , X exists, 1
2'l n-1n Furthermore, the scheduled extraction times for these pieces of steel are [1°12
．． 13. ..., 1. 1. The n-1n current temperatures of these steel pieces are respectively θ1. θ2. θ3. ..., θn-“1
゜θ, If the target temperature curve of these steel slabs is A, then by using the above equation (1), the furnace temperature θ2 required to raise the temperature to the extraction target temperature, respectively.

θ θ ..., calculating θ θ is g
2'g3'gn-1' gn can be done.

These furnace temperatures θ8. ．． θg2' θ2゛3.・－・、
As shown in Figure 3, θ8□-1゜θ is the highest gn near the extraction port, and it may decrease as the distance from the extraction port increases, or in a narrow range as shown in Figure 4. There may be slight variations, or, as shown in FIG. 5, the furnace temperature θ of the steel slab S may be significantly higher than gn, although it gradually decreases as the distance from the extraction port increases.

The present invention compares the target temperature of the material to be heated with the current temperature and selects a method for calculating the furnace temperature set value θ, for example, from among the following three methods.

(1) Furnace temperature θ θ θ ..., θ θ is gl'g2'g3'gn-1' g
As shown in Figure 3, the one closest to the extraction port has the highest
If it is predicted that the temperature will decrease as the distance from the extraction port increases, focus on the steel slab S1 on the extraction port side, and set the furnace temperature θ2□ obtained from the steel slab S1 as the furnace temperature set value θg'set.

(2) Furnace temperature θ8. ．． θg2'0g3' ..., 0
gn-1' If θgn varies slightly in a narrow range as shown in Fig. 4, all steel pieces Sl, S
2. S3゜..., pour into S S and set the furnace temperature θg
t' θ8□.

n-1'n θ ..., θ θ is weighted averaged and the average g
3'gn-1'gn Equal furnace temperature 1 is determined, and this average furnace temperature 1 is set as the furnace temperature setting g value θ. Note that the weighted averaging method g
Examples of set include the following methods, and select one of these methods.

(a) Give the same weight to all n pieces of steel.

(b) Add greater weight to the steel piece on the extraction port side.

(c) Among the n pieces of steel, a larger weight is given to the pieces with insufficient tempering (those whose material humidity is lower than the target temperature curve).

(3) Furnace temperature θ θ θ ..., θ θ is gl' g2° g3'・gn-1' g
As shown in Fig. 5, the furnace temperature θgn of the steel slab S is extremely high, although it gradually decreases as the distance from the extraction port increases.
Focusing on the furnace temperature θ, the furnace temperature stage n
Let gn constant value θ, be.

To do this, first, the material data and process data entered manually through the input means are stored in the memory, while the steel pieces St, S2 are set by the position calculation means.

S ... 3 at each extraction time of S and S
The future position of the control zone at ``n-1n'' is calculated.Then, the temperature calculation means is used to calculate the future position of the control band at point S1, S2, S3, etc.

The current temperature of each of S and S is estimated and stored in memory n-1.
Store it in n.

Next, the target temperature curve indexing means selects the steel piece S1. S2゜S
... Future position of S S and material data 3"
When the target temperature of the steel billet is indexed based on n-1' n and process data, the optimal furnace temperature set value calculation method selection means selects the method including weighted averaging based on the relationship between the target temperature and the current temperature. The optimal method is selected from among multiple methods for calculating the furnace temperature set value.

When the optimum furnace temperature setting value calculation method selection means selects weighted averaging, the optimum weighting coefficient calculation means selects the optimum weighting coefficient from the above-mentioned methods. Therefore, the optimum furnace temperature set value calculation means adjusts the temperature at which the billet is extracted from the control zone to the target temperature according to the selected optimum furnace temperature set value calculation method, and in some cases also uses the optimal weighting coefficient. Calculate the furnace temperature set value.

As a result, even if steel slabs with different fired states coexist in the control zone, highly accurate temperature control is possible without over-heating or under-heating.

(Embodiment) FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention together with a control system for a continuous heating furnace.

In the figure, a continuous heating furnace 1 equipped with burners in each control zone of a pre-heating zone, a heating zone, and a soaking zone is equipped with a steel billet extraction means 2 for extracting steel billets from an extraction port according to a rolling schedule. Further, in addition to providing a furnace temperature sensor 3 for detecting the furnace temperature and a furnace temperature control means 4 for controlling the furnace temperature by adjusting the fuel injection amount of the burner, the furnace temperature sensor 3 corresponds to each control zone. Input the output signal of the continuous heating furnace 1 and the billet extraction signal of the continuous heating furnace 1,
A furnace temperature setting device 10 is provided which calculates a furnace temperature set value and gives a steel billet extraction command to the steel billet extraction means 2 and a furnace temperature setting signal to the furnace temperature control means 4.

Here, the furnace temperature setting device 10 is intended to control a soaking zone having a steel billet extraction port, and includes material data such as dimensions, material, and surface temperature limit value of the steel billet, type of process, and extraction target temperature. , input means 11 for inputting process data such as required time, etc.
In addition to storing input data of this input means 11, a memory 1 stores current temperature data obtained by estimating the current temperature.
2, an extraction pitch calculation means 13 for calculating the scheduled extraction pitch until the steel billet is extracted from the soaking zone of the continuous heating furnace 1, and a position calculation means for calculating the future position of the steel billet using this scheduled extraction pitch. 14, and a temperature operator stage 1 that calculates the current temperature of the steel billet and sequentially updates the estimated temperature data in the memory 12.
5, a target temperature curve indexing means 16 for indexing the target temperature of the steel slab in the control zone using a target temperature curve corresponding to the material of the steel slab, and an optimum furnace according to the distribution state of the target temperature of the steel slab. The optimum furnace temperature set value calculation method selection means 17 selects the calculation method of the temperature set value, the optimum weight coefficient selection means 18 selects the optimum weighting coefficient to be used for calculating the optimum furnace temperature set value, and selects the optimum furnace temperature set value calculation method according to the selected calculation method. , and an optimum furnace temperature setting value calculation means 19 for calculating the optimum furnace temperature setting value for the control zone.

The operation of this embodiment configured as described above will be explained.

The continuous heating furnace 1 heats the steel billets inserted through the insertion port in different ways in a plurality of control zones, that is, a preheating zone, a heating zone, and a soaking zone, and then extracts the heated billets by the billet extraction means 2. Extract sequentially from the extraction port. At this time, the furnace temperature in the upper and lower parts of the soaking zone is detected by the furnace temperature sensor 3, and when the furnace temperature setting device 10 sets the optimum furnace temperature based on the detected value, the furnace temperature control means 4 sets the furnace temperature. Control the furnace temperature independently according to the value.

Here, in order to set the furnace temperature, material data such as the dimensions, material, and surface temperature limit value of the steel billet, and process data such as the type of process, extraction target temperature, and required time are inputted using the input means 11. These data are stored in memory 12.

Moreover, every time a steel billet is extracted from the continuous heating furnace 1, an extraction signal is applied to the extraction pitch calculation means 13 and the temperature calculation means 15. Based on this and the process data stored in the memory 12, the pitch to be extracted until after a certain period of time is calculated. Further, the position calculating means 14 calculates the future position of the soaking zone of the steel billet at the scheduled extraction time determined from this scheduled extraction pitch.

On the other hand, the temperature calculating means 15 receives the extracted signal obtained from the continuous heating furnace 1, and stores the detected value of the furnace temperature of the furnace temperature sensor 3 and the memory of the temperature calculated by the temperature calculating means 15 in the past.
The average temperature of the steel slab is calculated and estimated from the average temperature calculation value of the steel slab stored in memory 1.
2.

Furthermore, the target temperature curve indexing means 16 indexes the target temperature of the steel billet from the position of the steel billet within the soaking zone obtained from the position calculation means 14 and the material data of the steel billet obtained from the memory 12. The optimal furnace temperature setting value calculation method selection means 17 selects the position of the steel billet within the soaking zone obtained from the position calculation means 14, the material data of the steel billet obtained from the memory 12, and the uniformity obtained from the target temperature curve indexing means 16. From the target temperature in the tropics, select a calculation method for the furnace temperature set value for controlling the heating furnace.

Furthermore, when weighted averaging is selected as the calculation method for the furnace temperature set value, the optimal weighting coefficient selection means 18 determines the position of the steel billet in the heating furnace obtained from the position calculation means 14 and the position obtained from the memory 12. The weighting factors described above are selected based on the material data of the steel billet.

Next, the optimum furnace temperature set value calculation means 19 uses the material data and the current estimated temperature data obtained from the memory 12,
From the target temperature of the steel billet obtained from the target temperature curve indexing means 16, the weighting coefficient obtained from the optimum weighting coefficient selection means 18, and the position of the steel billet in the heating furnace obtained from the position calculation means 14, the above (1) ) is used to calculate the furnace temperature setting most suitable for the fired state of the steel slabs present in the control zone.

Based on the furnace temperature setting value calculated in this manner, the furnace temperature control means 4 controls the furnace temperature of the upper and lower portions of the soaking zone of the continuous heating furnace 1.

Thus, according to this embodiment, they are mixed in the soaking zone. Even if the firing state of the steel billet changes, fine-grained control is possible, and when each billet is extracted, the deviation between the extraction temperature of that steel billet and the extraction target temperature is kept to a minimum. The temperature of the control zone can be set with high precision.

In addition, in the above embodiment, the furnace temperature setting device 10 for controlling the furnace temperature in the soaking zone was explained, but the movement of the steel billet from the preheating zone to the heating zone, and the movement of the steel billet from the heating zone to the soaking zone. If these are regarded as extraction of steel pieces from the preheating zone and heating zone, respectively, it can also be applied to temperature control of the preheating zone and heating zone.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the furnace temperature setting value is calculated by selecting the optimal calculation method according to the distribution state of the target temperature of the steel billet, so that Even if different pieces of steel coexist in the control zone, there is an effect that highly accurate temperature control is possible with no shortage of overheating or hardening.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
Figures 2 to 5 are for explaining the principle of the embodiment.
It is a diagram showing the relationship between the position of a steel piece and temperature. 10...furnace temperature setting device, 11...input means, 12.
...Memory, 13...Extraction pitch calculation means, 14...
・Position calculation means, 15...Temperature calculation means, 16...
Target temperature curve indexing means, 17...Optimum furnace temperature setting value calculation method selection means, 18...Optimum weighting coefficient selection means, 19
...optimum furnace temperature set value calculation means. Applicant's representative: Sato -Yu 0: Target temperature

Claims (1)

[Claims] It has a control zone that can independently control the temperature, has a plurality of materials to be heated, and can be moved sequentially toward the extraction port, and has a control zone that can control the temperature of the furnace in this control zone. Furnace temperature setting for a continuous heating furnace in which the calorific value is controlled so that the deviation between the detected value and the set value becomes zero, characterized in that the continuous heating furnace is equipped with each of the means set forth in the following items a to i. Device. a. Input means for inputting material data such as the dimensions, material, and surface temperature limit value of the material to be heated, and process data such as the type of process, extraction target temperature, and required time. b. A memory that stores estimated temperature data for each of the materials to be heated, and also stores material data and process data input by the input means. c. Extraction pitch calculation means for calculating a scheduled extraction pitch until the material to be heated is extracted from the control zone based on the process data stored in the memory. d. Position calculating means for determining a scheduled extraction time from the scheduled extraction pitch calculated by the extraction pitch calculating means and calculating the future position of the material to be heated within the control zone at this scheduled extraction time. e. Estimating the current temperature of each of the materials to be heated based on the detected value of the furnace temperature in the control zone and the estimated temperature data stored in the memory, and sequentially updating the estimated temperature data in the memory. Temperature calculation means. f. storing a target temperature curve of the material to be heated, and based on the future position of the material to be heated calculated by the position calculating means and the material data and process data stored in the memory; Target temperature curve indexing means for indexing the target temperature of the material. g. Based on the future position of the heated material calculated by the position calculation means, the material data and estimated temperature data stored in the memory, and the target temperature indexed by the target temperature curve index means, Optimal furnace temperature set value calculation method selection means for selecting an optimal calculation method from a plurality of furnace temperature set value calculation methods including weighted averaging. h. When the optimal furnace temperature setting value calculation method selection means selects weighted averaging, based on the future position of the material to be heated calculated by the position calculation means and the material data stored in the memory. optimum weighting coefficient selection means for selecting an optimum weighting coefficient; i, the future position of the material to be heated in the heating furnace calculated by the position calculating means, the material data stored in the memory, the target temperature indexed by the target temperature curve indexing means, and the optimum weighting coefficient; When the material to be heated is extracted from the control zone according to the optimal furnace temperature set value calculation method selected by the optimal furnace temperature set value calculation method selection means based on the optimal weighting coefficient selected by the selection means. Optimal furnace temperature set value calculating means for calculating a furnace temperature set value for the control zone such that the temperature of the heated material matches a target temperature.