KR100823621B1 - Width Control Method Considering Width Change of Slab in Entrance and Exit side of Heating Furnace - Google Patents

Abstract

The present invention provides a first step of receiving the rough rolling entrance slab width (W), and storing and defining it,

A second step of calculating the rough rolling exit target width BR and the finishing rolling exit target width BF;

Width spreading amount ΔWD in the third step,

A fourth step of calculating the total width rolling amount ΔBT,

In the width control method in the rough rolling consisting of a fifth step of controlling the rolling mill by the total width rolling amount (ΔBT),

A first step of obtaining the average slab width WO by actual measurement of the slab width gauge 11 on the charging side of the heating furnace 13,

A first step of obtaining a slab width W1 in which the width variation is considered by actual measurement of the thermometer 10 on the charging side and the extraction side of the heating furnace 13,

It consists of a 1c step of replacing the slab width (W1) with the rough rolling inlet slab width (W) value of the first step.

According to the present invention, the rough rolling load side width W1 can be calculated from the furnace charging side slab width performance (WO), the charging temperature and the extraction temperature, and the width spreading amount and the width rolling amount in the rough rolling (20). Since it is used in the calculation, the width variation generated by the input slab 13 and the width variation generated in the playing process are sufficiently reflected, so that a more accurate calculation is possible than in the case of applying the conventional theoretical slab width (SLW). The degree of rolling control has been greatly improved, and there is an effect of minimizing width defects in the rough rolling 20 process and obtaining a quality that meets the required width of the final demand price.

Furnace, slab, width, width control

Description

Width Control Method Considering Width Change of Slab in Entrance and Exit side of Heating Furnace}

1 is a view schematically showing a hot rolling process,

2 is a view schematically showing a facility for performing width control during a hot rolling process;

3 is an explanatory diagram showing a conventional width control method for each step;

4 is an operation explanatory diagram showing the width control method according to the present invention for each step;

5 is a view showing the width hit ratio at the time of work by the conventional width control method,

6 is a view showing a width hit ratio when the width control method according to the present invention is applied,

7 is the expansion rate curve,

8 is a flowchart illustrating a conventional width control method;

9 is a flowchart illustrating a width control method of the present invention.

<Description of Symbols for Major Parts of Drawings>

11: heating furnace charging side slab width gauge 13: heating furnace

15: finishing rolling 17: cooling equipment

19: Down coiler 20: Rough rolling                 

21: rolling mill, heavy sizing edger (HSE)

23: rolling mill, edger A (E2A; Edger A) 25: rolling mill, edger B (E2B; Edger B)

27: first roughing mill (R1)

29: second roughing mill (R2)

30: Furnace control computer (Process Computer 1)

35: crude rolling control computer (Process Computer 2)

40: Business Computer (BC)

The present invention relates to a width control method in a rough rolling process in consideration of the slab width change of the furnace side during the online hot rolling process, and in particular, in setting the material width rolling amount, the width of the rolled material on the furnace side and the extraction side is determined. The present invention relates to a width control method in rough rolling that can maximize the width quality of a material after rolling by setting the width control in the rough rolling process by predicting optimally.

In general, as shown in FIG. 1, the hot rolling process is a process of heating a raw material through a heating furnace 13, treating the same in a rough rolling 20, and then finishing finishing 15, followed by post-treatment. . Among these, rough rolling 20 process is the width rolling in the width rolling mill (21, 23, 25) while passing the material through the first roughing mill 27 and the second roughing mill 29 as shown in FIG. Is carried out.                         

At this time, the main purpose of the width control in the width rolling is to ensure the required quality of the demand price and to facilitate the mail-sending during the finishing rolling 15, which is a post-process, so the setting of the amount of the width rolling is very important.

Conventionally, the rolling reduction amount, the opening degree, and the like of the rolling mills 21, 23, and 25 are considered in consideration of the conditions such as dimensions and components based on the material information transmitted from the operation computer 40 for the width control in the rough rolling 20. The rolling speed and the like were calculated and set.

Conventionally, as shown in FIG. 3, the slab theoretical width SLW is first transmitted from the operation computer 40 to the rough rolling control computer 35, and the coil width required by the demand is the rough rolling control computer. It is input to 35. After the width control setting calculation is performed by the rough rolling control computer 35, the data is transmitted to the control device of each rolling mill 21, 23, 25. Then, the control apparatus of each rolling mill 21, 23, 25 was made to perform width control automatically by this control amount.

In other words, when the rolling control computer 35 receives the slab theoretical width SLW from the operation computer 40 as shown in FIG. 8, the rough rolling side slab width W is

Can be stored and defined.

And the crude rolling target width (BR) is                         

Calculated as, and the finishing rolling target width (BF) is

Is calculated. here

to be.

On the other hand, the width spread (ΔWD) during the dog bone rolling

Is calculated as

to be.

And the total width rolling amount (ΔBT) is                         

Is calculated as

to be.

However, in the workflow of the conventional width control method as described above, the initial width information given when the rough rolling control computer 35 calculates the width setting amount is the slab theoretical width SLW received by the operation computer 40. This is information and there is a problem in using it as it is without any processing.

The slab theoretical width (SLW) is the width value predicted to be made naturally when cast according to the setting of the player (not shown) calculated according to the demand of the demand. Therefore, it is not verified whether the width is actually cast as predicted.

If the slab theoretical width (SLW) in the playing process is to be used in the rough rolling process, which is a post process, in most cases it must be assumed that the casting is completed as predicted. When this assumption is realistic to some extent, it can be used as it is as hot rolling width information in rough rolling. Since rough rolling calculates width rolling amount ((DELTA) BT) based on this, reliability of the magnitude | size of the width dimension in the playing process which is the previous process is very important.

In practice, however, there are many errors in the width dimension of the slab during the casting process. For example, there are many correlations between width dimension errors, such as mold width setting degree, hot correction value, and whether scarfing is performed. Nevertheless, in the conventional method, the slab theoretical width (SLW) in the hot rolling process is not sufficiently recognized in the hot rolling process, and the slab theoretical width (SLW) value is used for the rough rolling width control without filtration. It was not reflected, and had a great influence on the width quality in rough rolling.

In particular, when the slab is introduced into the hot rolling furnace 13 in the playing process, as well as its own error factors in the playing process, the temperature of the material is too high, or is completely cooled. There are also various states in the temperature of the material. By the way, since the temperature of the raw material is a very important factor in the examination of the width dimensional error, the variation in the prediction accuracy in the hot rolling process occurs more seriously, which causes a problem of lowering the width quality.

That is, as shown in the above equations, the slab theoretical width (SLW) value given by the operation computer 40 is incorrect, or the width change caused by the temperature of the actual material afterwards is accurately tracked as accurately as possible to input accurate width information. If not, all of the calculation results of the width spreading amount and the calculation result of the width rolling amount are inevitably different, and thus, there is a problem that the rolling mills 21, 23, 25 of rough rolling cannot be controlled at the exact width rolling amount.

The present invention has been made to solve the above-mentioned conventional problems, by measuring the slab width (WO) and the temperature at the charging side of the furnace 13, and by measuring the slab temperature at the extraction stage of the furnace (13) From this, width control considering the slab width change at the inlet / outlet of the heating furnace in which the rough rolling 20 loading side slab width W1 is obtained and the slab width W1 thus calculated is applied to the width control in the rough rolling 20 is obtained. To provide a way.

In order to achieve the above technical problem, the present invention provides a first step of receiving and storing and defining a rough rolling entrance slab width (W) as shown in FIG. 8,

Rough rolling exit target width (BR) by the following equation (2)

The second step to calculate,

Mapping rolling target width (BF) by the following equation (3)

The third step to calculate,

Width spreading amount (ΔWD) by the following equation (4)

4th step to calculate,

The total width rolling amount (ΔBT) by the following equation (5)

5th step to calculate,

In the width control method in the rough rolling consisting of a sixth step of controlling the rolling mill (21, 23, 25) by the total width rolling amount (ΔBT),

A first step of obtaining the average slab width WO by actual measurement of the slab width gauge 11 on the charging side of the heating furnace 13,

A first step of obtaining a slab width W1 in which the width variation is considered by actual measurement of the thermometer 10 on the charging side and the extraction side of the heating furnace 13,

By equation 9

It consists of a 1c step of replacing the slab width (W1) with the rough rolling inlet slab width (W) value of the first step.

In particular, the average slab width WO in the first step is expressed by Equation 6

here

Obtained as

Taking into account the above information, the slab linear expansion coefficient at the time of charging and extracting the furnace 13 and the slab temperature, the slab clothing at the time of extraction (W1: rough rolling side slab width) is expressed by equation (7).

here

It is preferable to configure to obtain.

That is, in the present invention, as shown in FIG. 4, not only the information from the operation computer 40 but also the slab temperature, the furnace furnace temperature, the slab width meter 11, and the like are collected in the furnace control computer 30. The furnace control computer 30 calculates the material width necessary for the rough rolling width control based on these information, and inputs it to the rough rolling control computer 35.

The rough rolling control computer 35 calculates each control amount based on this and inputs it to the controller of the rolling mills 21, 23, 25 to perform the width control.

More specifically, as shown in FIG. 9, the average value (WO) obtained by calculating the measured width data of several times measured by the slab heating furnace charging side slab width gauge 11 installed at the front end of the hot rolling furnace 13. Precalculate

Thereafter, the temperature measured value of the charged slab measured by the charging-side thermometer 10 is collected in the furnace control computer 30, and the slab charged together with the data in the furnace control computer 30 is heated to the furnace 13. At the time of extraction, the amount of change due to the environment expected when the charging slab enters the rough rolling 20 entrance side is extracted by using the ambient temperature measured value.

In consideration of the expected slab width change in the extraction step, the set rough rolling 20 entry slab width W1 is transmitted to the rough rolling control computer 35. Then, the rough rolling control computer 35 defines this as the amount of storing it in the variable W and using it as a future material width value.

The rough rolling control computer 35 is estimated by the control conditions in the rolling mills 21, 23, 25, and the first and second roughing mills 27, 29, and the width change according to the demand and the reduction of demand. The exit target widths BR and BF of rough rolling and finishing rolling are calculated by the following equations (2) and (3).

In addition, considering the set rough rolling 20 entry slab width W1 and the exit rolling target width BR of the rough rolling 20, the width spreading amounts of the first and second roughing mills 27 and 29 are represented by Equation 4. Calculate by

Subsequently, the total width rolling amount for calculating the rolling amount for controlling the full width rolling mills 21, 23, and 25 in consideration of the calculated width spreading amount and the thermal correction coefficient, etc. Obtain

Thereafter, the total width rolling amount is calculated as the width rolling amount for each pass in each width rolling mill 21, 23, 25, and the width rolling amount for each pass is for each rolling mill 21, 23, 25. By transmitting data Data to each controller, width rolling is performed by controlling the rolling mills 21, 23, and 25 by using the data, thereby enabling optimal width rolling.                     

Hereinafter, the operation of the present invention having the configuration as described above in detail.

First, in the step of obtaining the measured width value of the raw material, the slab width immediately before charging the furnace 13 is measured N times in the furnace charging side slab width gauge 11, and based on this, the largest width Mxw and the small width ( Obtain the average value (WO: slab width measurement width) divided by the measured score excluding Mnw).

here

to be.

Then, in the step of converting the influence of the temperature on the entry side of the furnace 13 into the width fluctuation amount, the charging temperature information measured by the charging side thermometer 10 is transmitted to the furnace control computer 30. Taking into account the slab linear expansion coefficient and slab temperature during charging and extraction of the furnace 13, the slab width (W1: rough rolling side slab width) during extraction is calculated using the following formula.                     

here

to be.

In this case, the linear expansion coefficient applied to the above equation is calculated by the expansion rate curve according to the temperature (T) shown in FIG. 7 and the linear expansion coefficient for each temperature section.

The slab width W1 thus obtained is transmitted to the rough rolling control computer 35 and stored, and this value is defined as the new width value.

Then, the rough rolling control computer 35 having this width information first finds the final target widths BR and BF at the exit of the rough rolling 20 and the finishing rolling 15. Here, the rough rolling target width BR is obtained by using Equation 2 as in the related art.

The finishing rolling target width BF is also calculated using the above equation (3) as before.

Using the rough rolling target width BR and the slab width W1 values thus obtained, the width spreading amount ΔWD is obtained using Equation 4 as in the prior art, and the width information used in Equation 4 is Is calculated by applying the actual width (W1) value considering the effect of actual measurement and temperature change, not the theoretical width value (SLW) received from the operation computer (40).

The width rolling amount ΔBT to be comprehensively applied using the calculated value ΔWD is calculated by using Equation 5 as in the related art.

The width rolling amount ΔBT obtained as described above is transmitted to an actual field machine control computer (not shown), and the width rolling for each pass in each rolling mill 21, 23, 25 is executed based on this, and thus the optimum width rolling amount is always obtained. And quality assurance control.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto, and the technical idea of the present invention and the following by those skilled in the art to which the present invention pertains. Various modifications and variations are possible without departing from the scope of the claims to be described in the following.

By applying the present invention as described above, it is possible to calculate the rough rolling charging side width W1 from the heating furnace charging side slab width performance (WO) and the charging temperature and the extraction temperature, and the amount of width spreading in the rough rolling (20) and Since it is used in calculating the width rolling amount, the width variation generated by the input slab 13 and the width variation generated in the playing process are sufficiently reflected, so that a more accurate calculation is possible than in the case of applying the conventional theoretical slab width (SLW). Accordingly, the width rolling control degree is greatly improved, and there is an effect of minimizing the width defect in the rough rolling 20 process and obtaining a quality that meets the required width of the final demand price.

Hereinafter, such an effect of the present invention will be described with reference to FIGS. 5 and 6.

5 is a width control hit ratio change when rolling by using the conventional width rolling control technology, Figure 6 is a width control hit rate change when rolling by applying the width rolling control technology according to the present invention.

As shown in the figure, when the rolled by the conventional control technology, the width control hit ratio of 40% or less is distributed a lot, when the rolled by applying the control technique of the present invention, the width control hit rate is less than 40% is found to be very small Can be.

In addition, in terms of the overall hit ratio distribution, while the conventional data is very sporadic distribution, it can be seen that the data distribution after applying the present invention is very evenly distributed.

Therefore, the present invention has a very large effect in improving the width control hit ratio and forming an even distribution.

Claims (2)

A first step of receiving the rough rolling entrance slab width (W), storing and defining the same; Rough rolling exit target width (BR) by the equation (2)

(Where BC: coil nominal width, C1: linear expansion coefficient, TFDT: pressure-controlled side temperature, TBL: table margin, Opm: operator's correction margin) The second step to calculate, Mapping rolling target width (BF)

Where TF6 is the frost target temperature The third step to calculate, Width spreading amount (ΔWD) by the equation (4)

(W: slab width, W _ERE : width _rolling efficiency (Table value)) 4th step to calculate, Total width rolling amount (ΔBT) by

(here,

And the fifth step of calculating In the width control method in rough rolling which consists of a 6th step which controls the rolling mills 21, 23, 25 by the said total width rolling amount ((DELTA) BT), A first step of obtaining the average slab width WO by actual measurement of the slab width gauge 11 on the charging side of the heating furnace 13, A first step of obtaining a slab width W1 in which the width variation is considered by actual measurement of the thermometer 10 on the charging side and the extraction side of the heating furnace 13, By equation 9

And a first step (c) of replacing the slab width (W1) by the rough rolling entry slab width (W) value of the first step. The method of claim 1, wherein the average slab width (WO) in the step 1a is expressed by Equation 6

(here,

), Taking into account the above information, the slab linear expansion coefficient at the time of charging and extracting the heating furnace 13 and the slab temperature, the slab clothing at the time of extraction (W1: rough rolling side slab width) is expressed by equation (7).

(here ,

Width control method considering the slab width change of the inlet and outgoing side, characterized in that obtained by the heating furnace.

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