KR100775462B1 - Rolling method of slab - Google Patents

Abstract

The object of the present invention is to extract the pitch by the constraint conditions between the slab wire and the trailing material in the rough rolling process, finishing rolling process, the rolling pitch by the constraint conditions for each winding machine, and the pitch by the furnace conditions Slab rolling method to reduce the amount of error in performance set amount by unifying the extraction pitch used for setting the furnace temperature and the actual pitch used by calculating the minimum extractable pitch and calculating the extracted pitch using it. In providing.

In order to achieve the above object, the present invention calculates and sets a reference extraction pitch value by compensating for a difference obtained by calculating and comparing a predicted value and an actual value of each zone (heating furnace, rough rolling, finishing rolling, winding) constraint. It is designed to minimize the amount of error in the performance set amount.

Rolling control, slab, heating furnace, rolling mill, winding machine

Description

Rolling method of slab

1 is a process chart for setting a reference extraction pitch according to the conventional method,

Figure 2 is a figure showing the extraction pitch by material width for each operation number of the furnace,

3a and 3b is a process chart for setting the reference extraction pitch according to the present invention,

4 is a graph showing a rolling process conveyance schedule prediction diagram according to the present invention,

5 is a graph showing the minimum extraction pitch of the line / trailing material from rough rolling to finishing rolling according to the present invention;

Figure 6 is a graph showing the minimum extraction pitch of the line / trailing material in the winding process according to the present invention,

7a and 7b is a graph showing the extraction pitch control results of the conventional and the present invention,

The present invention relates to a slab rolling method, and more particularly, the extraction pitch by the constraint conditions between the slab wire and the trailing material in the rough rolling process, the rough rolling process, and the rolling pitch according to the constraints of the winding machine operation period. Calculate the pitch according to the furnace condition, convert the minimum extractable pitch, and control the extraction pitch by using it to unify the extraction pitch used for the furnace furnace setting and the pitch used for the actual extraction, thereby generating an error in the performance set amount. The slab rolling method to reduce the amount.

In general, a process of rolling a slab to make a strip is carried out by charging a slab that has already been produced into a heating furnace, heating it to a target temperature, extracting the heated slab from the heating furnace into a rolling mill, and then rolling the slab through rough rolling and finishing rolling. It consists of the process of winding up from odor.

On the other hand, the crude rolling is provided with three stands and the slab extracted from the heating furnace passes through each of the stands two times or more, passing through the rolling is made and finally finish (finishing) rolling while passing through the finishing mill. In addition, about three heating furnaces for heating the slabs are provided, and about two winding machines are provided.

The general rolling process of rolling the slabs to produce the strips as described above is to give the respective conditions (work conditions necessary for rolling the slab) to the furnace, the rolling mill (coast rolling finishing) and the winder according to their constraints. Rolling continues in real time.

However, the constraints for each zone are already established, and the length and width of the slab change from time to time in order to produce a strip that is intended to revive the requirements of the consumer. Therefore, the slab rolling method as shown in Figure 1 is provided and used in order to revive the size of the slab that changes frequently, and the method is described in detail as follows.

The method of determining the conventional reference extraction pitch shown in FIG. 1 is based on the extraction pitch correction term according to the final product thickness, width, charging interval, and zero time of the furnace operation as shown in Table 1 below. The extracted pitch reference value for each material was calculated as in Equation 1 below.

TABLE 1

Heating furnace Museum ← Finished Product Thickness → Thicken 1 unit 122 120 118 116 108 110 112 114 116 118 120 122 2 units 190 185 180 175 160 165 170 175 180 185 190 195 3 units 230 228 220 215 210 205 200 210 220 224 227 230

[Equation 1]

Pitch = Ttime × 60 / (FL / (SW + l))

Ttime = Actpch × FN × (FL / (SW + l)) × FN

Pitch: Standard extraction pitch

Ttime: reference material time

SW: material width

l: Long time for material heating

FL: Overall length of the furnace

FN: Number of furnace operation

Actpch: Performance Extraction Pitch

The conventional rolling control as described above is for the purpose of maximizing the productivity of the rolling process and the efficiency of energy use of the furnace process, which is intended to increase the maximum productivity with the minimum use of fuel.                         

In the conventional rolling control having the above purpose, the furnace is operated by considering only the heating pattern for securing the material (slab) temperature, and in the rolling process, the operation is operated as the working pattern only for securing the operationability of finishing rolling. Due to the diversification of the situation (slave size change), material diversity (slave material change), and dualization management of the extraction pitch control system, there is a problem that the extraction pitch control according to the characteristics of the material is difficult.

The present invention has been made to solve the above problems in consideration of the above problems, the object of the present invention is to extract the pitch by the constraints of the furnace, and the constraint conditions between the slab wire / trailing material in the rough rolling, finishing rolling process The present invention provides a slab rolling method for minimizing the amount of error in the performance set amount by calculating the extraction pitch and the rolling pitch according to the constraints of the winding machine operating periods and using the same.

Referring to the technical features of the slab rolling method of the present invention for achieving the above object is as follows.

In the present invention, in the slab rolling method consisting of the first step to select the slab for the production of the desired strip to charge in the heating furnace and then heating, rolling and winding the slab,

Extraction pitch based on the pre-set heating furnace constraint, extraction pitch based on the constraint between slab leading material in the roughing process, rolling mill, and rolling mill, and rolling pitch according to the constraints of the number of winding machines A first step of predicting a return schedule value from the heating furnace to the winder;

Calculate the extraction pitch by the constraints of the slab-loaded furnace, calculate the extraction pitch by the constraints between the slab leading material in the rough rolling and finishing rolling processes. A second step of obtaining a return schedule value from the actual heating furnace to the winder obtained by calculating the roll pitch;

A third step of obtaining a reference extraction pitch value by compensating for a difference obtained by comparing a return schedule predicted value from the heating furnace to the winder of the first step with the actual return schedule value from the heating furnace to the winder of the second step; It is supposed to include.

Referring to the slab rolling method of the present invention having such a feature in detail with reference to the accompanying drawings as follows.

The present invention heats the slab according to the heating furnace constraints already set as shown in FIG. 3A, and predicts the extracted pitch of the heated slab, and in the rough rolling and finishing rolling (finishing rolling, finishing rolling) processes, which are the rolling processes. The predicted extraction pitch due to the constraints between the slab leading material and the predicted rolling pitch according to the constraints of the winding machine operation are calculated to obtain the total return schedule prediction value from the heating furnace to the winding machine.

In addition, the actual return schedule from the heating furnace to the winder is calculated in the same manner as the method for obtaining the total return schedule prediction value from the heating furnace to the winder, in which a slab is charged into the heating furnace and the slab is charged. Calculate the actual extraction pitch by the constraints of the heated furnace, calculate the actual extraction pitch by the constraints between the slab leading materials in the rough rolling and finishing rolling processes Calculate the actual rolling pitch by

As described above, when the total return schedule prediction value and the actual value from the heating furnace to the winder are obtained, the reference extraction pitch value is obtained by compensating for the difference value obtained by comparing them.

On the other hand, before charging the slab into the heating furnace, it is determined whether or not the charged slab is suitable for the purpose of the strip to be produced, and if it meets the above standard, charge it into the heating furnace and do not charge into the heating furnace if it does not meet the specifications. However, the slab charged in the furnace is different in length, width and thickness depending on the use of the strip produced by rolling or the requirements of the required person. It is therefore necessary to choose the slab charged into the furnace depending on what the production of the strip is for.

On the other hand, when the slab is charged into the furnace, the charged slab is heated according to the constraints of the furnace and extracted with a rolling mill. The constraint of the furnace is that the slab is a certain degree in the furnace. It means stagnant with time and how much to maintain the pitch of the preceding extraction slab and the trailing extraction slab according to the stagnation.

The slab must be stagnated in the furnace under the constraints of the furnace, in order to roll the slab, the slab must be heated, because it ensures the heating time. The heating rate (time) is different, and as the slab proceeds inside the furnace, the heating furnace temperature is different according to each section in the heating furnace, and accordingly, the heating rate (time) of the slab is different. However, the heating rate (time) varies depending on the length, width and thickness of the slab, depending on the use of the strip and the requirements of the person required.

In addition, the number of heating furnaces for heating the slab and extracting it with a rolling mill is about three, and since the three positions are different from each other, the distance from the rolling mill is also slightly different. Therefore, it is necessary to compensate for the slab extracted from the furnace because the time to arrive in the rolling mill is also slightly different.

When the heating of the slab is completed as described above, the rolling is carried out using a rolling mill. The rolling mill for rolling the heated slab is divided into rough rolling and finishing rolling. The slabs that are prepared and rolled through the three stages are rolled as the slab moves forward and backward as each passage passes. And finishing rolling is also called finish rolling as finishing rolling.

In addition, the constraints of the rolling mill as shown in Figures 4 to 6, the slab extracted from the furnace can be rolled forward / backward in the rough rolling mill and the rolling speed of the rolled slab proceeds and the acceleration, etc. At the same time as calculating their schedules, the rolling speed of the finishing mill, the moving speed of the slab to be rolled, and the acceleration thereof are mentioned.

On the rolling mill as described above, the slab extracted from the heating furnace is continuously rolled in real time, and such rolling must maintain a proper pitch between the preceding slab and the trailing slab so that rolling is normally performed.

The extraction pitch according to the constraint conditions between the slab wire and the trailing material in the rough rolling and finishing rolling process is obtained by the following equation (1).

[Equation 1]

PITMi = TA (Pi) + ΔTi-TB (Qi)

PITM = max [PITM1, PITM2... … PITMn]

i.n: Number of constraints

PITMi: Extraction pitch that satisfies condition i

TA (Pi): The time when the leading line (end) reaches the Pi point first or last.

TB (Qi): Based on the starting point of trailing material extraction, when the trailing material line (the end) reaches the Qi point first or last.

ΔTi: Time passed by the leading edge or trailing edge after passing the leading edge or trailing edge

Then, when the slab line / in the rough rolling and finishing rolling process is obtained, the rolling pitch according to the constraint conditions for each of the winding machine moving machines is calculated.

[Equation 2]

PITCH = TY (# 1.PR) + ΔT-TB (# 1.PR)-(PitACT1 + PitACT2)

TY (# 1.PR): # 1.PR OFF time of Y tail end.

TB (# 1.PR): # 1.PR ON time of B end step.                     

PitACT1: Extraction pitch performance between Z and A materials.

PitACT2: Extraction pitch performance between Y and Z materials.

The extraction pitch under the constraints of the heating furnace is obtained by the following equation.

[Equation 3]

TextNO = TextO + max (PitM, PitF, Pitmin)

TextNO: Pre-set value of vehicle extraction time.

TextO: Reprinting extraction time.

PitM: Mill line timeout

PitF: Automatic combustion control setting extraction pitch.

Pitmin: Table Pitch.

In addition, if the reference extraction pitch value obtained by the predicted value and the actual value is fed back to the step of charging the slab which is an initial stage into the heating furnace, the rolling control is continuously and in real time, and the automatic combustion control and rough rolling of the heating furnace are performed. Feedback of the slab forward / reverse count finishing rolling of the process to the initial stage of charging the slab into the heating furnace also has the advantage of continuous and real time rolling control.

Figure 8a of the present invention is a graph showing the extraction pitch results by the conventional method, Figure 8b is a graph showing the extraction pitch results according to the present invention, using the reference extraction pitch values obtained by the method of the present invention as shown here As a result of applying the rolling control of the actual slab, it can be seen that the error occurrence rate between the performance settings was reduced by more than 50% compared to the conventional one, and the hit ratio increased by more than 100% within ± 30 seconds.

The present invention has been described in the above-mentioned work orders, furnace combustion control, rough rolling setting, finishing rolling correction model, change of extraction pitch due to manual intervention of the operator, event (slave progress signal) performance in the rolling line of the extraction material, and each zone (heating furnace, Rough rolling, finishing rolling, winding) The results are summarized and the winding completion history of the material is integrated to minimize errors by predicting and correcting measurements through learning.

As described above, the present invention compensates the difference obtained by comparing the return schedule prediction value from the heating furnace to the winding machine and the actual return schedule value from the heating furnace to the winding machine to obtain a standard extraction pitch value and apply the value to the rolling control. By doing so, there is a unique effect of minimizing the amount of error between performance settings and improving the hit rate.

Claims (6)

In the slab rolling method comprising the step of selecting the slab for the production of the desired strip and charging it in a heating furnace, heating, rolling and winding the slab, Extraction pitch based on the pre-set heating furnace constraint, extraction pitch based on the constraint between slab leading material in the roughing and rolling milling process, and rolling pitch according to the constraints for each operation period of the winding machine A first step of predicting a return schedule value from the heating furnace to the winder; Calculate the extraction pitch by the constraints of the slab-loaded furnace, calculate the extraction pitch by the constraints between the slab leading material in the rough rolling and finishing rolling processes. A second step of obtaining a return schedule value from the actual heating furnace to the winder obtained by calculating the roll pitch; A third step of obtaining a reference extraction pitch value by compensating for a difference obtained by comparing a return schedule predicted value from the heating furnace to the winder of the first step with the actual return schedule value from the heating furnace to the winder of the second step; Slab rolling method comprising a. 2. The slab rolling method according to claim 1, wherein the extraction pitch is obtained by the following equation between the slab leading and trailing materials in the rough rolling and finishing rolling process. PITMi = TA (Pi) + ΔTi-TB (Qi) PITM = max [PITM1, PITM2... … PITMn] i.n: Number of constraints PITMi: Extraction pitch that satisfies condition i TA (Pi): The time when the leading line (end) reaches the Pi point first or last. TB (Qi): Based on the starting point of trailing material extraction, when the trailing material line (the end) reaches the Qi point first or last. ΔTi: Time passed by the leading edge or trailing edge after passing the leading edge or trailing edge The slab rolling method according to claim 1, wherein the rolling pitch is obtained by the following formula according to the constraints for the number of movable winding machines. PITCH = TY (# 1.PR) + ΔT-TB (# 1.PR)-(PitACT1 + PitACT2) TY (# 1.PR): # 1.PR OFF time of Y tail end. TB (# 1.PR): # 1.PR ON time of B end step. PitACT1: Extraction pitch performance between Z and A materials. PitACT2: Extraction pitch performance between Y and Z materials. The slab rolling method according to claim 1, wherein the extraction pitch under the constraint of the heating furnace is obtained by the following equation. TextNO = TextO + max (PitM, PitF, Pitmin) TextNO: Pre-set value of vehicle extraction time. TextO: Reprinting extraction time. PitM: Mill line timeout PitF: Automatic combustion control setting extraction pitch. Pitmin: Table Pitch. The slab rolling method according to claim 1, wherein the reference extraction pitch value obtained by the predicted value and the actual value is fed back to an initial stage to continuously control rolling. The slab rolling method according to claim 1, wherein the rolling is controlled continuously by feeding back the set value of the slab forward / reverse number finishing rolling of the heating furnace and the rough rolling of the slab to the initial stage.

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