JP2001205317A - Method for extracting steel in continuous hot-rolling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel extracting method in continuous hot-rolling by which the time required by the time the steel reaches the position of the target catching-up section is minimized, moreover, joining is surely performed by making the rear end of a preceding material and tip end of the succeeding material reach the target catching-up section at proper timing and which deals with the sudden change of a rolling schedule. SOLUTION: This method is a steel extracting method by which, using a correction value F(t) for correcting an extracting interval between the preceding material and the succeeding material from a heating furnace 13, the succeeding material is extraced at the extracting time Ti+1=Ti+A-B+F(t) from the heating furnace 13. The correction value F(t) is the correction amount of a actual standby time which is determined from the difference between the standby starting time when the succeeding material reaches a standby position before reaching the target catching-up section and the time when the standby of the succeeding material stood by in the standby position is released and, by feeding back the correction amount to the extracting interval between the preceding material and the succeeding material from the heating furnace 13, the extracting time of the following succeeding material from the heating furnace 13 is decided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for extracting a steel material to be subjected to continuous hot rolling from a heating furnace.

[0002]

2. Description of the Related Art Hot rolling of steel materials has been performed intermittently, for example, on steel sheets (also called slabs) one by one. However, in this method, hot rolling of unsteady portions at the front end and rear end of the steel sheet is performed. Due to the tension, scratches and shape defects were easily generated on the steel sheet. Also,
In the steel sheet, defects in the sheet width and the sheet thickness occur due to a change in the threading speed, and furthermore, an increase in the hot rolling speed causes an inferior rolling temperature and surface quality, resulting in a decrease in yield. For this reason, a great deal of time and labor has to be spent on the work of removing the defective portion, the work of adjusting the finishing board, and the like. Therefore, in order to improve the above, a so-called continuous hot rolling method in which a plurality of steel sheets for hot rolling are successively joined and rolled continuously at a predetermined speed has been attempted in recent years.

A continuous hot rolling method is disclosed in, for example,
As described in Japanese Patent No. 3724, the following procedure is performed. (1) Coarse hot rolled steel sheet or high-temperature thin-wall continuous cast slab (flat or coil) to be supplied to a continuous hot rolling mill
The front end and the rear end of the steel material for hot rolling are cut in advance by a flying crop shear. (2) The whole or a part of the rear end cut surface of the preceding material and the front end cut surface of the following material is welded and joined. (3) A large number of hot-rolled steel sheets are hot-rolled sequentially with the same rolling schedule or continuously with a plurality of schedules while changing the relay. (4) After hot-rolling, split and cut, and alternately take-up processing by a plurality of take-up machines. As a result, hot rolling of the steel sheet can be performed without spending a great deal of time and effort in removing defective parts, finishing the work of the passing plate, etc., which are caused by intermittent hot rolling of the steel sheet one by one. Became possible.

However, in continuous hot rolling, it is difficult to make the rear end of the preceding material and the front end of the following material reach the target follow-up section position with good timing and join them. If the extraction time of the succeeding material from the heating furnace is slow, joining becomes impossible because the front end of the following material cannot catch up with the rear end of the preceding material within the target additional section position. In the case where the extraction time of the following material from the heating furnace is early, it is necessary to make the following material wait in front of the joining machine until the rear end of the preceding material reaches the target follow-up section position. This is because the temperature of the subsequent material decreases, and as a result, the temperature required for hot rolling cannot be secured, and hot rolling cannot be performed. When the above problems occur, continuous hot rolling must be interrupted during hot rolling. As a result, a large amount of labor and time is required for the recovery for performing the continuous hot rolling, the facility operation rate is significantly reduced, and further, the advantage of improving the yield by the original continuous operation cannot be enjoyed. Had also occurred.

Therefore, as described in Japanese Patent Application Laid-Open No. 9-262610, the rolling speed, sheet thickness,
Using various rolling conditions such as advanced rate and table transfer speed, for each of the continuous material from the leading material to the final material, the time required for rolling is predicted, and the leading end of the succeeding material after rough rolling is determined as the leading material. There has been proposed a method of determining a time interval (extraction interval) of extracting a preceding material and a succeeding material by a heating furnace, which is necessary for joining to a rear end.

[0006]

However, in the above-mentioned method, the time required for rolling is estimated for each of the continuous rolled material from the first material to the last material, and the time required for rolling is used. It is not possible to consider the error with the actual value that occurs. Therefore, as the number of continuous rolled materials from the first material to the last material increases, the error in the results increases, so that the rear end of the preceding material and the front end of the following material reach the target tracking section position at appropriate timing. It becomes difficult to make it. The present invention has been made in view of such circumstances,
Minimize the time required for the steel to reach the target tracking section position, and ensure that the rear end of the preceding material and the front end of the following material reach the target tracking section position at the appropriate timing. It is an object of the present invention to provide a method for extracting a steel material of continuous hot rolling that can be joined and can easily cope with a sudden change in a rolling schedule.

[0007]

According to the present invention, there is provided a method for extracting steel in continuous hot rolling according to the present invention, comprising: a first step of extracting steel heated to a predetermined temperature from a heating furnace; and a rough rolling of the heated steel. A second step of joining, the third step of joining the roughly rolled steel, and a fourth step of finish rolling the joined steel, maintaining the finishing temperature of the subsequent material required in the fourth step,
In addition, a correction value F (t) for correcting the extraction interval of the preceding material and the following material from the heating furnace so that the front end of the following material can reach the rear end of the preceding material at the preset target follow-up section position. Is used to extract the succeeding material at the time T _{i + 1} = T _i + A−B + F (t).
A steel material extraction method for extracting from a heating furnace by using a correction value F
(T) is obtained from the difference between the standby start time at which the following material arrives at the standby position before reaching the target follow-up section position and the time at which the subsequent material waits at the standby position and is released from standby. The correction amount is an actual standby time correction amount, and the correction amount is fed back to the extraction interval of the preceding material and the succeeding material from the heating furnace, and the extraction time of the succeeding subsequent material from the heating furnace is determined. Where T _i
Is the time when the preceding material was extracted from the heating furnace, A is the estimated time from when the preceding material was extracted from the heating furnace to when the rear end of the preceding material reaches the target follow-up section position, and B is the following material Is a predicted time from the time when is extracted from the heating furnace until the front end of the following material reaches the target follow-up section position.

[0008] The actual standby time is that the steel material is made to stand by before reaching the target follow-up section position, so that the time is consumed until there is no problem even if a collision occurs. This is the actual waiting time of the trailing material for joining the trailing end and the leading end of the trailing material. Since the correction value F (t), which is the correction amount of the actual standby time, is fed back to the extraction interval of the preceding material and the succeeding material from the heating furnace, the sheet length, rolling speed, sheet thickness, etc. of the preceding material If the rolling conditions differ between the set value and the actual value and an error occurs, the time required for the steel to reach the target follow-up section position is minimized, and the error between the predicted value and the actual value is minimized. In consideration of the above, the rear end of the preceding material and the front end of the following material can be securely joined at the target follow-up section position, and further, the following material of the following material can be easily handled even if the rolling schedule is suddenly changed. The time of extraction from the heating furnace can be determined.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is an explanatory diagram showing the position and time from extraction to joining in the method for extracting steel material in continuous hot rolling according to one embodiment of the present invention, and FIG. 2 shows the method for extracting steel material in continuous hot rolling. FIG. 3 is a flowchart illustrating a continuous hot rolling steel extraction method, and FIG. 4 is a flowchart illustrating a correction amount determining method in the continuous hot rolling steel extraction method. is there.

As shown in FIG. 2, a continuous hot rolling apparatus 10 applied to a continuous hot rolling steel extraction method according to one embodiment of the present invention includes A heating furnace 13 for heating the steel sheet 12 to a finishing temperature (for example, about 1100 to 1200 ° C.), a VSB rolling roll 14 for roughly rolling the heated steel sheet 12, a R1 rolling roll 15,
2 Rolling Roll 16, R3 Rolling Roll 17, R4 Rolling Roll 18 and Joining Device 19 for Joining Roughly Rolled Steel Plate 12
And a finish rolling roll (not shown) for finish-rolling the joined steel sheet 12, and continuously rolls the steel sheet 12 extracted from the heating furnace 13.

Here, the VSB roll 14 is a vertical roll for adjusting the width of the steel sheet 12 to be roughly rolled. On the other hand, R1 rolling roll 15, R2 rolling roll 16,
The R3 rolling roll 17 and the R4 rolling roll 18 are horizontal rolls for adjusting the thickness of the steel plate 12, respectively. Before the R3 rolling roll 17, the following material can be made to wait before reaching the target follow-up section position. Further, in the joining device 19, the rear end of the preceding material and the front end of the following material are brought close to each other within 100 mm, respectively, fixed with clamps, and the both ends are butt-joined to form a distance type laser welding machine. Is used to join the butted portions.

A method for extracting a steel material in continuous hot rolling according to an embodiment of the present invention includes a first step (extraction step) of extracting a steel sheet 12 heated to a predetermined temperature from a heating furnace 13, and a method of extracting the steel sheet 12. Step (coarse rolling step) for roughly rolling the steel sheet, third step (joining step) for joining the coarsely-rolled steel sheet 12 (leading material, succeeding material), and fourth step (finishing) for finish rolling the steel sheet 12 Rolling process). In order to carry out continuous hot rolling, it is necessary that when the rear end of the preceding material reaches the target follow-up section position, the front end of the succeeding material after rough rolling has reached the target follow-up section position. is there. However, since the preceding material is rolled by finish rolling rolls, various rolling conditions such as the rolling speed in the finish rolling process, the sheet thickness, the advance rate, and the table transfer speed greatly affect the moving speed of the rear end of the preceding material. Will be done.

From this, first, the preceding material is extracted from the heating furnace 13 based on various rolling conditions such as the rolling speed, plate thickness, advance rate, and table transfer speed in the rough rolling and finish rolling. A predicted time that is considered to be required for the rear end to reach the target tracking section position is obtained. Next, the actual standby calculated from the difference between the standby start time at which the following material arrives at the standby position before reaching the target tracking section position and the time at which the subsequent material at standby at the standby position is released from standby. The time correction amount is fed back to the extraction interval of the preceding material and the succeeding material from the heating furnace 13, and the extraction time of the following material from the heating furnace 13 is obtained. Thus, a method of determining the extraction time of the steel sheet 12 from the heating furnace 13 without interrupting the continuous hot rolling and without significantly lowering the temperature of the steel sheet 12 was studied.

FIG. 1 predicts, based on the extraction time T _i of the preceding material extracted from the heating furnace 13, the extraction time T _{i + 1} of the succeeding material extracted from the heating furnace 13 next. By extracting the following material at the extraction time T _{i + 1} , the rear end of the preceding material and the front end of the following material can reach the target follow-up section position, and as a result, joining can be performed. It is shown that it becomes. In addition, the vertical axis | shaft of FIG. 1 is a path | route until the steel plate 12 is extracted from the heating furnace 13, and reaches the target follow-up section position,
The horizontal axis indicates elapsed time. The predicted extraction time T _{i + 1} of the succeeding material is expressed by the following equation. T _{i + 1} = T _i + A−B + F (t) (1) where T _i is the time when the preceding material is extracted from the heating furnace 13, and A is when the preceding material is extracted from the heating furnace 13. From
The predicted time until the trailing end of the preceding material reaches the target tracking section position, B is from when the trailing material is extracted from the heating furnace 13 until the front end of the trailing material reaches the target tracking section position. , F (t) is a correction value.

The extraction interval between the preceding material and the succeeding material is calculated as a difference (A−B) by predicting and calculating A and B, respectively. Here, A is the transport time from the completion of the extraction of the preceding material to the arrival of the rear end of the preceding material at the target tracking section position. This is the sum of the transport time required to reach the attached section position and the time C during which the preceding material passes through the target added section position.
B is the time from when the extraction of the following material is completed to when the front end of the following material reaches the target follow-up section position. Here, whether or not the trailing edge of the preceding material and the leading edge of the following material follow at the target tracking section position is determined by the joining shear (the rear edge of the preceding material and the leading edge of the following material). In order to perform the joining reliably and easily, the joining is first performed by a device for cutting the end of the steel plate 12). This is because there is a restriction that the joining shear cuts the front end of the following material several seconds after cutting the rear end of the preceding material. The method of calculating the time from the completion of the extraction of the following material to the front end of the following material reaching the target follow-up section position is determined by each of the rough rolling mills (VSB rolling roll 14, R1 rolling roll 15, R2 rolling roll 16, R3
Rolling speed setting of the rolling rolls 17 and R4 rolling rolls 18 and the length of the material on the delivery side, and the table (hot rolling line 1)
1) It can be obtained from the transport speed.

C can be obtained from the length of the steel sheet of the preceding material and the passing speed at the target follow-up section position. The passing speed at this position is restricted by the finish rolling speed of the joined preceding material and the material before that. Therefore, when the downstream material of the preceding material is extracted, the finish rolling speed setting of the material and the length of the steel plate 12 are obtained and stored, and are used when calculating the passing speed of the preceding material.

Next, the concept of the correction value F (t) will be described. The correction value F (t) is the difference between the standby start time at which the following material arrives at the standby position before reaching the target tracking section position and the time at which the subsequent material waits at the standby position and is released from standby. This is the correction amount of the actual standby time calculated from. If each of the preceding material and the following material reaches the target follow-up section position at the predicted time, the steel sheet 12 may be extracted from the heating furnace 13 at the predicted time. However, in practice, each of the preceding material and the following material does not always reach the target follow-up section position at the predicted time due to an error in the thickness of the steel plate 12, an error in the transport speed, or the like. Therefore, in order to perform continuous hot rolling, the extraction time of the steel sheet 12 is set so that the front end of the following material collides with the rear end of the preceding material just before the target follow-up section position. However, unless this time is set to a time that does not cause a problem even before the collision reaches the target tracking section position (actually, the preceding material and the following material are fixed by the clamp in the target tracking section position). The steel plate 12 stagnates on the hot rolling line 11, and continuous hot rolling cannot be performed.

In view of this, a standby position is provided as a place where adjustment can be made to a time where there is no problem even if a collision occurs before the target tracking section position, that is, a state having a margin time α. As a result, even if an error in the transport time occurs after the standby position, the error can be compensated for. However, in the standby position, if the standby time until the adjustment to the allowance time α is long, the temperature of the joined steel sheets 12 cannot be maintained at the temperature required for finish rolling. The correction value F (t) was determined from the desired time. The margin time α is about 2 to 10 seconds. As a result, even if an error occurs between the actual time required for the steel sheet 12 to reach the target follow-up section position and the predicted time calculated in advance, a great deal of labor and time is required to restore hot rolling. Continuous hot rolling can be performed without causing a significant reduction in the facility operation rate.

Next, as one of concrete methods for obtaining the predicted times A and B from the time when the steel sheet 12 is extracted from the heating furnace 13 to the time when the steel sheet 12 reaches the target follow-up section position, the following method is used. The method of is shown. The rolling time of the rolling roll in the rough rolling step, and the rolling roll in the finish rolling step, the thickness and length before and after the rolling, as well as the advance rate and reverse rate can be predicted,
The time from when the leading end of the steel sheet 12 enters the rolling roll to when the rear end of the steel sheet 12 passes through the rolling roll can be expressed by the following equation. Rolling time = L / (V × (1-b)) (2) where L is the length of the steel sheet 12 before rolling, V is the set rolling speed (roll speed), and b is the reverse speed. is there. Further, the transport time of the steel sheet 12 between the adjacent rolling rolls can be easily calculated from the transport speed of the hot rolling line 11 and the distance between the respective facilities.

Next, a method for extracting a sheet of continuous hot rolling according to an embodiment of the present invention will be described with reference to the flowchart of FIG. In step S1, extracted from the heating furnace 13 to the first preceding material extraction time T _i. In step S2, using the various rolling conditions such as the rolling speed, the sheet thickness, the advance rate, and the table transfer speed in the rough rolling of the preceding material, the rear end of the preceding material is added to the target after the extraction from the heating furnace 13. A predicted time A until the vehicle reaches the attached section position is calculated. Similarly, in step S3, prediction of the subsequent material from the time when it is extracted from the heating furnace 13 using the various rolling conditions in the rough rolling until the front end of the subsequent material reaches the target follow-up section position. Calculate time B. Next, in step S4, in step S1, the preceding material is the heating furnace 1
And time T _i which is extracted from the 3, the correction value of the preceding material previously extracted steel sheet 12 from the F (t) to the original, the extraction time T _{i + 1} of the next strip using equation (1) Predict. Then, in step S5, the succeeding material is extracted from the heating furnace 13 at the extraction time T _{i + 1} . Next, in step S6, the VSB rolling roll 14, the R1 rolling roll 15, and the R2 rolling roll 1
6, and rough rolling is sequentially performed.

In step S7, the following material reaches the standby position. At this time, the front end of the following material is detected by a reflection type optical sensor (material load sensor), and the arrival time is stored. In step S8, the time required for the rear end of the preceding material to reach the target follow-up section position from the current position of the preceding material (the predicted transport time after the current position) is calculated, and the arrival time is predicted. Similarly, at this time, assuming that the following material advances without waiting at the standby position, the front end of the following material reaches the target follow-up section position based on the arrival time at which the following material arrives at the standby position. Calculate the time required until the transfer (predicted transfer time after the current position), and predict the arrival time.

In step S9, this standby position (R3 in this embodiment) before reaching the target follow-up section position.
Before the rolling roll 17), it is calculated whether or not the following material needs to wait. This is because the predicted time at which the front end of the following material having the margin time α reaches the target follow-up section position is compared with the predicted time at which the rear end of the preceding material reaches the target follow-up section position by the following formula. To decide. X + (surplus time α)> Y (3) Here, X is the predicted time for the front end of the following material to reach the target tracking section position, and Y is the rear end of the preceding material to the target tracking section position. The time it takes to reach. Accordingly, when the predicted time at which the front end of the following material reaches the target tracking section position is earlier than the predicted time at which the rear end of the preceding material reaches the target tracking section position, a standby time is required. At this time, the following material stands by between the R2 rolling roll 16 and the R3 rolling roll 17 in Step S10, and after 50 milliseconds, Step S8 is performed.
Return to

On the other hand, the predicted time at which the trailing end of the preceding material reaches the target tracking section position is the same as the predicted time at which the leading end of the following material having a margin time α reaches the target tracking section position,
Or, when the predicted arrival time of the front end of the following material becomes late (except when the front end of the following material is delayed by more than 60 seconds from the schedule, for example, to reach the target follow-up section position) In step S11, the standby of the following material is released, and the process proceeds to step S12, where the rolling of the following material is restarted. Here, if the delay is 60 seconds or more, when the trailing end of the preceding material reaches the target follow-up section position, the front end of the following material cannot reach the target follow-up section position. Is not implemented. Next, the following material is roughly rolled by the R3 rolling roll 17 and the R4 rolling roll 18. In step S13, the front end of the following material reaches the target follow-up section position, and the rear end of the preceding material reaching the target follow-up section position in step S14 can be joined to the front end of the following material.

When the standby is released in step S11, as shown in FIG. 4, the correction amount is determined by the following method at the same time. In step S15, the actual standby time is obtained from the difference between the standby release time in step S11 and the arrival time at which the standby position has been reached in step S7.
In step S16, whether the actual standby time is within the appropriate value,
Calculate whether or not. The appropriate value is about 2 to 20 seconds (about 10 seconds in this embodiment). At this time, if the actual standby time is within the appropriate value, step S17
, The correction amount of the extraction interval of the following material from the heating furnace 13 is set to 0, and the succeeding subsequent material is extracted from the heating furnace 13 as predicted without correcting the extraction interval of the following material. On the other hand, if the actual standby time is outside the appropriate value, for example, about 21 to 60 seconds, the correction amount of the succeeding material extraction interval is calculated in step S18, and the correction amount is determined in step S19. By feeding back this correction amount to the extraction interval from the heating furnace 13, the extraction time of the succeeding material can be corrected.

In the above embodiment, the first step of extracting the steel sheet heated to a predetermined temperature from the heating furnace, the second step of roughly rolling the heated steel sheet, and the third step of joining the roughly rolled steel sheet are performed. The fourth step of finishing and rolling the joined steel sheet
The continuous hot rolling method having the above steps is described. However, the winding (coil box) process, which can reduce the equipment installation location by winding the steel plate, the cutting process of cutting the end of the steel plate to improve the joining of the rough-rolled steel plate, It is also possible to have a scale removing step of removing generated scale by pressurized water, a heating step of performing heating to stabilize the structure of the joint, and the like.

In the above-described embodiment, one VSB rolling roll having a vertical roll is used in the rough rolling step. However, depending on the rolling conditions of the steel sheet to be rolled, the equipment cost, and the equipment installation space, etc. It is also possible to install more than one. A total of four R1 rolling rolls, R2 rolling rolls, R3 rolling rolls, and R4 rolling rolls having horizontal rolls were used. However, depending on the rolling conditions of the steel sheet to be rolled, equipment costs, equipment installation space, etc.
It is also possible to install three units or five or more units.

In the above-described embodiment, as a method of sensing at the standby position where the steel plate is made to stand by, a material load sensor is attached, but another detection method, for example, a television camera or the like can be used. And in the said embodiment, although joining using the laser welding method as a joining method of the rear end of the preceding material and the front end of the following material,
It is also possible to use other joining methods, for example, an arc welding method, a plasma welding method, or the like. The welding machine used in this laser welding method is a running laser welding machine, but may be a fixed type.

Further, in the above embodiment, the standby position of the following material is arranged before the R3 rolling roll. This standby position is set to a certain thickness (for example, 70 to 9).
(Approximately 0 mm), and a position where the rear end of the preceding material and the front end of the succeeding material can reliably follow each other at the target catching section position. (For example, a location close to the target tracking section position),
It is necessary to have the following two conditions. This is because, when the thickness of the steel sheet is reduced, the heat radiation from the end of the steel sheet increases, which hinders continuous hot rolling. This is because continuous hot rolling would have to be interrupted if the precision required to keep up with the above was not obtained.

[0029] From this, it is possible to suppress the temperature drop at the end of the steel sheet, and to obtain the accuracy with which the rear end of the preceding material and the front end of the succeeding material can reliably follow at the target follow-up section position. The standby position was arranged in front of the R3 rolling roll as a place where the heat treatment can be performed. However, if the above conditions can be satisfied, a coil box (apparatus for winding a steel sheet after rough rolling), which is located before the target follow-up section position, even before the R3 rolling roll, R1 rolling roll,
It is also possible to arrange it before the R2 rolling roll. Note that, here, one steel sheet can be placed on standby between adjacent rolling rolls. However, this is because there is one steel sheet between adjacent rolling rolls, and there is a steel sheet rolled by the rolling roll. Includes the case.

[0030]

According to the method for extracting steel material of continuous hot rolling according to the first aspect, the correction value F is obtained from the correction amount of the actual standby time.
By obtaining (t), it is possible to feed back to the extraction interval of the preceding material and the succeeding material from the heating furnace, so that the rolling conditions of the preceding material, such as the sheet length, rolling speed, and sheet thickness, are adjusted. The difference between the set value and the actual value, even if an error occurs, minimizes the time required for the steel to reach the target follow-up section position, and furthermore, considers the error between the predicted value and the actual value. In order that the rear end of the preceding material and the front end of the following material can be reliably joined at the target follow-up section position, and that a sudden change in the rolling schedule can be easily dealt with, The extraction time can be determined. As a result, the rear end of the preceding material and the front end of the following material can reach the target follow-up section position in a timely and reliable manner, so that workability is improved and productivity is improved. It is possible to carry out continuous hot rolling capable of suppressing the occurrence of hot rolling.

When the time for extracting the succeeding material from the heating furnace is short, the succeeding material needs to wait in front of the joining machine until the rear end of the preceding material reaches the substantial joining position. For this reason, it is possible to solve the problem that the temperature of the succeeding material decreases, and as a result, the temperature required for finish rolling cannot be secured, and rolling cannot be performed. As a result, workability is good, operation troubles can be suppressed, and abrupt changes in the rolling schedule can be dealt with, so that hot rolling can be performed, which can enjoy the advantage of improved yield by continuous operation. Becomes

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing positions and times from extraction to joining in a method for extracting steel materials in continuous hot rolling according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a continuous hot rolling apparatus applied to a steel material extraction method of the continuous hot rolling.

FIG. 3 is a flowchart showing a method for extracting a steel material in the continuous hot rolling.

FIG. 4 is a flowchart showing a method for determining a correction amount in the method for extracting steel material in the continuous hot rolling.

[Explanation of symbols]

10: continuous hot rolling device, 11: hot rolling line, 1
2: steel plate, 13: heating furnace, 14: VSB rolling roll, 1
5: R1 roll, 16: R2 roll, 17: R
3 rolling rolls, 18: R4 rolling roll, 19: joining device

Claims (1)

[Claims] 1. A first step of extracting a steel material heated to a predetermined temperature from a heating furnace, and a second step of roughly rolling the heated steel material.
And a third step of joining the roughly rolled steel material, and a fourth step of finish rolling the joined steel material, maintaining a finishing temperature of a subsequent material required in the fourth step, Moreover, in order to enable the front end of the succeeding material to reach the rear end of the preceding material at a preset target follow-up section position, a correction value for correcting the extraction interval of the preceding material and the following material from the heating furnace. F
Using (t), the succeeding material is extracted at time T _{i + 1} = T _i + A−
A method for extracting a steel material from the heating furnace by B + F (t), wherein the correction value F (t) is a standby start when the succeeding material reaches a standby position before reaching the target follow-up section position. And a correction amount of the actual standby time obtained from a difference between the time and the time when the following material waiting at the standby position is released from the standby state, and the correction amount is the heating furnace of the preceding material and the following material. A method of extracting the steel material of the continuous hot rolling, wherein the extraction time is determined from the heating furnace by feeding back to the extraction interval from the heating furnace. Here, T _i is the time when the preceding material was extracted from the heating furnace, A is the predicted time from when the preceding material was extracted from the heating furnace to when the rear end of the preceding material reached the target follow-up section position, B is a predicted time from when the following material is extracted from the heating furnace to when the front end of the following material reaches the target follow-up section position.