JPH01281391A - Furnace temperature setting device for a continuous heating furnace - Google Patents

Abstract

PURPOSE:To perform a high accurate temperature control by a method wherein a baked condition of a steel piece within a heating furnace is discriminated in reference to material, manufacturing steps, a surface temperature and an estimated value of material temperature and the like, the most suitable steel piece to be noted is estimated to calculate a furnace temperature set value. CONSTITUTION:A furnace temperature setting device 10 may retrieve a target temperature of an inner-furnace steel piece with a retrieving means 16 in reference to a material from an inputting means 11, data of steps, an estimated present temperature data of a memory 12 revised in sequence by a temperature calculating means 15 and a present position of the steel piece to be calculated by a calculating means 14 form an extracted and planned pitch by a calculating means 13 and then a difference with a mean temperature estimated value when passed through an outlet of controlling band is calculated by a calculating means 17. The most-suitable furnace temperature determining means 18 may edit data with an editing part 19, estimate a steel piece to be noted in reference to a knowledge data of a memory part 20 and determine a furnace temperature set value of a heating furnace 2 for baking up the steep piece. In this way, even if the steel pieces having different baked condition are present, a temperature control of a high accuracy can be carried out.

Description

[Detailed description of the invention] [Structure of the invention] (Industrial application field) The present invention provides a furnace temperature setting device for a continuous heating furnace that heats a piece of material to be heated (hereinafter referred to as a steel piece) such as a slab or billet. More specifically, the present invention relates to a furnace temperature setting device for a continuous heating furnace that individually sets the furnace temperature of each control zone in order to individually control the furnace temperature of each of a plurality of control zones through which steel billets continuously pass.

(Prior Art) As a typical conventional continuous heating furnace, there is a belt-type continuous heating furnace having three control zones: a pre-heating zone, a heating zone, and a soaking zone.

This double-zone continuous heating furnace has a burner that burns the injected fuel, a furnace temperature sensor that detects the furnace temperature, a furnace temperature value detected by the furnace temperature sensor, a furnace temperature setting device, etc. for each control zone. The control device is configured to control the deviation of the furnace temperature setting value close to zero, so that the temperature can be controlled independently in each MgIJ band.

The steel piece is heated while successively 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. It is common for a plurality of steel slabs to exist in these control zones, and furthermore, the dimensions and materials of the steel slabs, extraction target temperature, temperature limit values shown in Table 1Ija, etc. are not necessarily the same. If the dimensions, material, extraction target temperature, surface temperature limit value, etc. of the steel slab are different, the furnace temperature must be reset each time a steel slab is extracted, and if the settings are not appropriate, the furnace temperature may It may not be possible to bake the Ml'+ present to the extraction target temperature, or conversely, the baking may be overdone during extraction.

In addition, for the steel slabs in the furnace, we calculated an appropriate furnace temperature setting value by considering the dimensions and material of the steel slab, extraction target temperature, surface temperature limit value, etc., and set it in the furnace temperature control device. Even in this case, there is a considerable time delay before the furnace temperature in the heating furnace is controlled to the furnace temperature set value by the furnace temperature 17 control device. Therefore, it is difficult to perform fine control by focusing on individual pieces of steel.

In order to solve this problem, while considering the characteristics of the heating furnace, we focus on the steel slab that is least tempered among the multiple steel slabs mixed in the heating furnace, and A possible method is to set the furnace temperature of the heating furnace so that the extraction target temperature can be reached during extraction. However, with this furnace temperature setting method, if there is even one piece of steel that is insufficiently fired in the same $1al zone of the heating furnace, it is necessary to focus on that piece of steel and set the furnace temperature higher. Therefore, in the same control band, many of the billets leading and trailing the missing billet are fired to a temperature significantly higher than the extraction target temperature of each billet. It ends up.

In addition, as another furnace temperature setting method, the extraction temperature of each steel billet during the time from the current time to the time when billets mixed in the same control zone of the heating furnace are extracted, while taking into account the characteristics of the heating furnace. is estimated, and in order to minimize the sum of the temperature differences or the sum of the squares of the temperature differences between this estimated extraction temperature value and the extraction target temperature, the process is performed from the current time until the pieces of rope mixed in the same control zone are extracted. A possible method is to calculate the furnace temperature set value at the time of . In this furnace temperature setting method, the furnace temperature setting value is calculated by pouring into all the slabs mixed in the same control zone of the heating furnace, so the calculated furnace temperature setting value is the average furnace temperature setting. value. For this reason, the extraction temperature of the least-hardened steel billet among the steel billets coexisting in the same control zone of the heating furnace may be considerably lower than the extraction target temperature. At this time, if the extraction temperature of [ is lower than the rolling iT capacity allowable extraction temperature of the next process, for example, the extraction should be delayed until the steel billet is heated to the rolling iT capacity allowable extraction temperature, that is, the heating furnace. You will have to wait. If this waiting time for the heating furnace occurs, the rolling production schedule will be significantly changed.

(The problem to be solved by the invention FXJ) The present invention has been made to solve the above-mentioned problem, and even when steel pieces with different fired states are mixed in the control zone, it is difficult to overheat or harden. It is an object of the present invention to provide a furnace temperature setting device for a continuous heating furnace that enables highly accurate temperature control without any deficiencies and can set the furnace temperature with little variation.

[Structure of the invention]

(Means for Solving the Three Problems) The furnace temperature setting device for a continuous heating furnace according to the present invention uses material data of the material to be heated, process data specific to the process, and material to be heated obtained as a result of past calculations. A memory for storing estimated temperature data of a piece, and a first calculation for calculating a scheduled extraction pitch until the material to be heated in the furnace is extracted from the continuous heating furnace based on the process data stored in this memory. means, a second calculation means for calculating the future position of the piece of material to be heated in the furnace at the extraction r fixed time calculated from the scheduled extraction pitch calculated by the first calculation means, and a furnace in each control zone. Estimating the current temperature of the piece of material to be heated based on the detected temperature value and estimated temperature data stored in the memory,
A third calculation means for sequentially updating the estimated temperature data in the memory, and a third calculation means for storing the target temperature at each lid of the furnace of the piece of material to be heated as a target temperature curve, and calculating the temperature of the piece of material to be heated calculated by the second calculation means. The port for indexing the target temperature of each piece of material to be heated at each lid in the furnace based on the future position and the material data and process data stored in the memory includes a temperature indexing means and a target temperature indexed by the target temperature indexing means. The target temperature of the material piece in the furnace, the current temperature of the material piece to be heated calculated by the third calculation means, the scheduled extraction pitch calculated by the first calculation means, and the target temperature calculated by the second calculation means. Based on the future position of the heating material in the furnace, the material temperature when the piece of material to be heated passes through the belt outlet of the heating furnace is pre-calculated M1, and the deviation between it and the target temperature is calculated. Rules for inferring the most suitable material to be heated and the rules for inferring the most suitable material to be heated to calculate the furnace temperature setting Exactly 1 when passing through the obi exit
A knowledge storage unit that stores rules for inferring a furnace temperature setting value for baking to a standard temperature, material data stored in the memory, and a heated object calculated by the first calculation means. The planned extraction pitch of the material pieces, the in-furnace position of the heated material piece calculated by the second calculation means, the current temperature of the heated material piece calculated by the third calculation means, and the calculation by the fourth calculation means. The most suitable piece of material to be heated that should be noted in order to calculate the furnace temperature setting value is found based on the band outlet temperature deviation determined and the rules stored in the knowledge storage unit. The apparatus is characterized in that it includes an inference section that infers a furnace temperature setting value for baking it to a target temperature when it passes through the outlet.

(Function) As shown in FIG. 2, a piece of steel S existing in one control zone of the heating furnace is at position X at time t. Assume that the furnace is located at position X1 at time t. 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 target temperature curve A is a series of these target values. Here, the target temperature at position X is T. , if the temperature at position X1 is T, then the steel piece S is at position X.

■ Time to move from position X to position Δt (-t, within -1°,
It is necessary to heat from the current temperature θ to the target temperature T1. The furnace temperature θ necessary for heating by this temperature difference Δθ (−71−θ.) can be calculated by the following equation using the surface temperature of the material.

+Φ (θ+273) l / fΦ +Φ l ]
]1/4-27LGI I
CGu CGI...(1) However, C: Specific heat (cal/) cg'c) ρ density (dan/rIt) b: Width of steel (m) σ: Stefan Boltzmann constant Φ. . U: Upper overall heat absorption rate Φ: Lower overall heat absorption rate CGI Δθ: Temperature deviation (-T1-θo) ("C) Δ: Time interval (=tl-to) (hr) θ: Furnace temperature (℃-θ) : Upper surface temperature of the steel piece ('C) θ1 : Lower surface temperature of the steel piece ('C).

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

S S is the extraction port (on the right side of the figure) or n-1, respectively.
'n and M positions (to the left) in order x, , x2 . x3゜...
, t3. ....

1.1. The current temperature of these pieces of steel is 1
1 θ , θ θ ..., θ 2 θ , if the target temperature curve of these 1 2' 3° n-1n steel pieces is A, the above (1)
By using the formulas, the furnace temperatures θ8□2 and θ8□ required to heat to the extraction target temperature, respectively.

θ..., g that can calculate θ θ
3'gn-1' gn These furnace temperatures θgl'0g2' 0g3. °・−
As shown in Figure 3, 1θgn-1'θ is highest in the gn closest to the extraction port, and decreases as the distance from the extraction port increases, or as shown in Figure 4, in a narrow temperature range. Alternatively, as shown in FIG. 5, only the furnace temperature θgn of the steel slab S may become extremely high, although it gradually decreases as the distance from the extraction port increases.

The present invention stores the operating know-how of a heating furnace operator as a knowledge base, and stores various data such as band exit temperature deviation of steel slabs mixed in the heating furnace, scheduled extraction time, material data, and process data. Input , and using that type 1 base,
Inferring the most suitable steel to be noted in order to calculate the furnace temperature setting value from the fired state of the steel billet in the heating furnace,
By determining the optimum furnace temperature setting value by inference so that the ji4g determined by inference is baked to the target temperature when passing through the band exit, the heating furnace is always kept in the optimum state, I!
! can be controlled.

For this purpose, first, the material data and process data inputted by manual means are stored in a memory, and the steel billet S1. S2S...,S
3' n at each extraction time of S
-1' Calculate the future position of the control band at n.

Then, the third calculation means calculates the steel billet S1. S2. S3.
....

The current temperature of each of 5n-1"'n is estimated and stored in the memory 1.

Next, the target temperature curve indexing means calculates the steel billet Sl-S2S.
..., S , future position of S and material data 3'
A target temperature of the billet is indexed based on the n−I n temperature and process data.

On the other hand, in order to infer the most suitable steel billet for calculating the furnace temperature set value and determine the optimal furnace temperature set value performance method and the optimal weighting coefficient to be used when calculating the optimal furnace temperature set value, Rules are stored in the knowledge storage section in advance.

Therefore, the material data stored in the memory, the planned extraction pitch of the steel billet calculated by the first calculating means, and the second
the in-furnace position of the steel billet calculated by the third calculation means, the current temperature of the steel billet calculated by the third calculation means, and the target temperature at the '6 position in the furnace of the steel billet indexed by the target temperature curve indexing means. , and the rules stored in the knowledge storage unit, infer the most suitable steel slab for calculating the furnace temperature set value, and determine the optimal eL calculation method for the optimal furnace temperature set value. Optimal weighting factors to be used when calculating the furnace temperature set point are deduced. The individual material temperatures are extracted when steel H is extracted from the continuous heating furnace based on each data used for this inference, the calculation method of the optimum furnace temperature setting value and the optimum weighting coefficient obtained by the inference. The furnace temperature setting value for each control zone is calculated so that the target temperature is maintained.

As described above, by storing the operational know-how of the heating furnace operator as a knowledge base and using this to infer the most suitable steel billet for calculating the furnace temperature setting value from the fired state of the steel billets in the furnace. , even if pieces of steel with different firing conditions are mixed in the heating furnace,
The optimum furnace temperature setting value can be set at all times, thereby achieving highly accurate temperature control without overbaking or underbaking.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention together with a control system for a continuous heating furnace. In the same figure, the preparatory zone,
The continuous heating furnace 2, which has burners in each control zone of the heating zone and the soaking zone, is equipped with a steel billet extraction means 3 for extracting steel billets from an extraction port according to a rolling schedule. Further, the continuous heating furnace 2 includes, for each control zone, a furnace temperature sensor 5 that detects the furnace temperature, and a furnace temperature control means 4 that controls the furnace temperature by adjusting the fuel injection amount of the burner. Furthermore, by inputting the output signal of the furnace temperature sensor 5 and the steel piece extraction (No. 2) of the continuous heating furnace 2, the furnace temperature setting value is calculated, and a steel piece extraction command is sent to the steel piece extraction means 3, and the steel piece extraction command is sent to the furnace temperature control means. 4 is provided with a furnace temperature setting device 2210 that provides a furnace temperature setting signal.

Here, the furnace temperature setting device 10 is intended to control a soaking zone having a steel billet extraction port, and the material data specific to the steel billet, such as the dimensions, material, and surface temperature limit value of the steel billet, and the type of heating process. , an input means 11 for manually inputting process data specific to the process such as extraction target temperature and required time, and a memory 12 for storing the manual data from the 11 stages 11 and for storing current temperature data obtained by estimating the current temperature. , the steel billet is continuously heated in furnace 2
an extraction pitch calculation means 13 for calculating the scheduled extraction pitch until extraction from the soaking zone; and a position for calculating the future position of the steel in the furnace at the scheduled extraction time determined from the extraction scheduled pitch calculated here. a calculation means 14; a temperature calculation means 15 that calculates the current temperature of the steel billet and updates the estimated temperature data from the memory 12; and a temperature calculation means 15 that calculates the current temperature of the billet and updates the estimated temperature data from the memory 12; a target temperature indexing means 16 for indexing the target temperature of the steel slabs in the heating furnace from data regarding the steel slabs; and a memory 1
2, the current average temperature of the steel billet and data about the steel billet, the scheduled extraction pitch until a certain period of time computed by the extraction pitch computing means 13, and the pitch of the steel billet computed by the position computing means 14. General inside continuous heating furnace 2
Zone outlet temperature deviation calculation for calculating the estimated value of the average temperature when the steel billet passes through the outlet of the control zone based on the position and the target temperature indexed by the target temperature indexing means 16, and calculating the deviation from the target temperature. and an optimum furnace temperature determining means 18 which determines and outputs an optimum furnace temperature setting value according to the distribution state of the target temperature.

The optimum furnace temperature determining means 18 includes a data editing section 19, a knowledge storage section 20, and an inference section 21.

In the data editing section 19, the future position data of the steel billet in the heating furnace calculated by the position calculation means 14, the current temperature, dimensions, material, etc. of the steel billet stored and held in the memory 12,
Data such as surface temperature limit value, zone outlet temperature deviation calculation means 1
The strip outlet temperature deviation data of the steel strip calculated in step 7, the extraction r constant pitch data calculated in extraction pitch calculation 13, etc. are edited and sent to the inference section 21. The inference unit 21 is
Based on these edited data and the rules stored in the knowledge storage unit 20 in advance, it is inferred and determined which steel billet is the most suitable to focus on in order to calculate the furnace temperature set value. Then, when the obtained piece of steel passes through the exit of the band, the piece of steel is seen! Infer and determine the oven temperature set point for baking to that temperature.

Here, the rule group stored in the wisdom storage unit 20 is a knowledge base that has conventionally been possessed by a heating furnace operator as operating know-how. A specific example of each rule making up the rule group will be explained.

Note that Δ is a logical formula symbol indicating an AND (logical product) condition.

(1) Example rule for determining which slab should be poured into (There is no temperature limiting material in the control zone) △ (Furnace location is close to the exit of the control zone) = (Calculate the furnace temperature set value by paying attention to that steel piece) Example 2
: (It is a temperature limiting material) △ (There is no other temperature limiting material in the same control zone) = (Calculate the furnace temperature setting value by pouring into the temperature limiting material) (2) Calculate the optimal furnace temperature setting value Example of rule to determine Nl; (Material dimensions are standard dimensions) △ (Material is hard-wearing material) Δ (Remaining furnace time is within 10 minutes) Δ (Control zone outlet temperature deviation is -30 ℃ to -15℃) △(No temperature limiting material) △(1, ij e! There is no temperature limiting material in the control zone) = (
(Raise the furnace temperature set value by 30°C above the standard value) The furnace temperature set value determined using such a rule is the furnace temperature setting device 1
Based on this furnace temperature set value, the furnace temperature of the continuous heating furnace 2 is controlled by the furnace temperature control means 4.

Next, the operation of the apparatus shown in FIG. 1 will be explained.

The continuous heating furnace 2 heats the steel slabs that are successively inserted from the insertion port in different ways in each control zone of a pre-heating zone, a heating zone, and a soaking zone, and extracts the heated steel slabs by the billet extraction means 3. Extract sequentially from the mouth.

At this time, the furnace temperature in the soaking zone is detected by the furnace temperature sensor 5, and when the furnace temperature setting device 10 calculates and sets the optimum furnace temperature based on the detected value, the furnace temperature control means 4 operates according to the furnace 7R setting value. Independently Control the Furnace Temperature Here, in order to set the furnace temperature, the manual means 11 inputs material data such as the dimensions, material, and surface temperature limit of the steel billet, as well as process type, extraction target temperature, required time, etc. When process data is input, these data are stored in the memory 12. In addition, each time a steel billet is extracted from the continuous heating furnace 2, the extraction pitch calculation-T stage 13
And the extraction signal is added to the temperature calculation means 15. The extraction pitch calculating means 13 calculates the pitch to be extracted until after a certain period of time based on this extraction signal and the work 11 data stored in the memory 12. Further, the position IfrLηf stage 14 calculates the future position of the soaking latent of the steel billet at the fixed extraction time determined from this scheduled extraction pitch.

On the other hand, the lu degree calculating means 15 receives the extraction signal obtained from the continuous heating furnace 2, and calculates the detected value of the furnace temperature from the furnace temperature sensor 5 and the temperature calculated by the temperature calculating means 15 in the past and stores it in the memory 12. The average temperature of the steel H is calculated and estimated from the calculated value of the calculated average temperature of the steel slab, and the stored contents of the memory 12 are updated based on the result. Further, the dP4 temperature 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 band outlet temperature deviation calculation means 17 uses the current average temperature of the steel slab and data about the steel slab stored in the memory 12, and the extraction schedule until after a certain time rl calculated by the extraction pitch calculation means 13. Pitch and position calculation means 14
From the future position of the steel billet in the continuous heating furnace 2 calculated by and the target temperature indexed by the target temperature indexing means 16, an estimated value of the average temperature when the steel billet passes through the exit of the control zone is calculated. Then, find the deviation from the target temperature.

The optimum furnace temperature determining means 18 is configured by a data editing section 18 editing each data from the memory 12, the extraction pitch calculation f/stage 13, the position calculation means 14, and the band outlet temperature deviation calculation means 17, and the data obtained therefrom. and the knowledge base stored in the knowledge storage unit 20 described above.
1 determines the furnace temperature setpoint.

Thus, according to this embodiment, even if the baking state of the steel H mixed in the soaking zone changes, it is most suitable for accurately determining it in a short time and calculating the furnace temperature setting value. The optimum furnace temperature setting value can be calculated based on this result, and the quality of the steel slabs can be uniformly controlled by eliminating variations in the furnace temperature setting value by heating furnace operators. be able to.

In addition, in the above embodiment, the furnace temperature setting device for controlling the furnace temperature in the soaking zone in particular 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. The present invention can also be applied to the temperature control of the preheating zone and the heating zone by considering them as the extraction of the steel billet from the preheating zone and the heating zone, respectively.

〔Effect of the invention〕

As is clear from the above description, according to the present invention,
Calculate the furnace temperature setting by quickly and accurately determining the fired state of the steel billet in the heating furnace from data such as material data, process data, and estimated surface temperature and material temperature. Infer the optimal billet to focus on,
Based on this inference result, it is possible to calculate the optimal furnace temperature setting, which allows you to maintain a highly accurate temperature that will not cause over-baking or under-baking, even when steel slabs with different firing states are mixed in the furnace. control can be achieved.

Further, according to the present invention, it is possible to eliminate variations in the furnace temperature set value by the heating furnace operator, thereby contributing to uniformity of the quality of the steel billets.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIGS. 2 to 5 are diagrams showing the relationship between the position of a steel billet and temperature for explaining the principle of the embodiment. 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 indexing means, 17... Band outlet temperature deviation calculation means, 18... Optimal furnace temperature determining means, 19... Data editing section, 20... Knowledge storage section, 21... Reasoning section. Applicant's agent Mr. Sato Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] Furnace temperature setting for a continuous heating furnace in which the optimal furnace temperature of each control zone is individually set in order to individually control the furnace temperature of each of a plurality of control zones through which a piece of material to be heated continuously passes. In the equipment, material data specific to the material to be heated, process data specific to the process,
and a memory for storing estimated temperature data of the piece of material to be heated obtained as a result of past calculations, and the piece of material to be heated in the furnace is extracted from the continuous heating furnace based on the process data stored in this memory. a first calculating means for calculating a scheduled extraction pitch up to the scheduled extraction pitch; and a second calculation means for calculating the future position of the piece of material to be heated in the furnace at the scheduled extraction time calculated from the scheduled extraction pitch calculated by the first calculating means. a third calculating means for estimating the current temperature of the piece of material to be heated based on the furnace temperature detection value of each control zone and the estimated temperature data stored in the memory, and sequentially updating the estimated temperature data in the memory; a calculation means for storing the target temperature of the piece of material to be heated at each position in the furnace as a target temperature curve, and a future position of the piece of material to be heated calculated by the second calculation means and material data stored in the memory. and a target temperature indexing means for indexing the target temperature of the piece of material to be heated at each position in the furnace based on the process data; Based on the current temperature of the piece of material to be heated calculated by the calculation means, the scheduled extraction pitch calculated by the first calculation means, and the future position of the piece of material to be heated in the furnace calculated by the second calculation means. , a fourth calculation means for predicting and calculating the material temperature when the piece of material to be heated passes through the belt outlet of the heating furnace and calculating the deviation between it and the target temperature; Rules for inferring the most suitable piece of material to be heated and calculation of the furnace temperature set point.The most suitable piece of material to be heated should be baked so that it reaches the target temperature when it passes through the band exit. a knowledge storage section that stores rules for inferring a furnace temperature setting value for the heating; 2
The in-furnace position of the piece of material to be heated calculated by the calculation means, the current temperature of the piece of material to be heated calculated by the third calculation means, the band exit temperature deviation calculated by the fourth calculation means, and knowledge. Based on the rules stored in the memory unit, the most suitable piece of material to be heated that should be noted for calculating the furnace temperature set value is found, and when the piece of material to be heated passes through the band exit, it is set to the target temperature. 1. A furnace temperature setting device for a continuous heating furnace, comprising: an inference section that deduces a furnace temperature setting value for baking.