JPH08155513A - Mill pacing method - Google Patents

Abstract

PURPOSE: To provide a mill pacing method which is capable of dealing with changes having the same direction in increasing or decreasing transportation time. CONSTITUTION: In a mill pacing method for controlling an interrolling pitch between the tail end of a preceding stock and the tip end of the succeeding stock, in a rolling line in which a transporting device 3 for controlling the speed for transporting a rolling stock 5 and a detector 4 for detecting the presence/absence of the rolling stock 5 are provided between a heating furnace 1 and a rolling mill 2; time To is detected by the detector 4 from the passing of the tail end of the preceding stock 5A until the passing of the tip end of the succeeding stock 5B. On the basis of the detected time To , when the transporting speed of the succeeding stock 5B is controlled in the transporting device 3 by means of a preset reference pattern, an estimated inter- rolling pitch T is determined which is from the passing of the tail end of the preceding stock 5A through a rolling mill 2 until the arrival of the tip end of the succeeding stock 5B at the rolling mill 2. A difference is calculated between the estimated interrolling pitch T and the preset target inter-rolling pitch tO; and this difference is added to the extract timing of the next rolling stock from the heating furnace 1, so that such timing is corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mill pacing method for controlling a pitch between rollings in a rolling line including a heating furnace and a rolling mill.

[0002]

2. Description of the Related Art In a rolling line in which a rolling mill is arranged next to a heating furnace, mill pacing is performed in order to minimize idle time of the rolling mill. As this kind of mill pacing method, for example, the method described in JP-A-4-123809 is known.

In this conventional device, the trailing end position of the preceding rolled material is tracked as a distance from the first rolling mill, and the leading end position of the following rolled material is moved from the heating furnace to the first position.
Arrival time calculation means for calculating the time to reach the rolling mill, and the distance obtained by the tracking means is the difference between the arrival time calculated by the arrival time calculation means and the inter-rolling pitch target time. The first rolling mill was provided with extraction control means for outputting an instruction to start extraction of the trailing rolled material at a timing that was equal to the product of the input speed.

This prior art is premised on that an instruction to extract the succeeding material from the heating furnace is issued after the preceding material is bitten into the first rolling mill. By the way, in recent years, in a situation where reheating of a heating furnace in a steel strip factory is actively carried out, a layout in which a distance from the heating furnace to the first rolling mill is about 30 m is separated, and thus the preceding material is first rolled. In some cases, it has been necessary to issue an instruction to extract a trailing material before it bites into the machine, making it difficult to apply the above-mentioned conventional technique.

Therefore, as described in Japanese Patent Laid-Open No. 154827/1994, a pinch roll is provided in the extraction transport line from the heating furnace to the first rolling mill, and after the tip of the trailing material reaches the pinch roll, the pinch roll is reached. A method has been proposed in which the conveyance speed of the succeeding material is controlled by rolls to correct or correct the variation in the conveyance time that occurs in the extraction conveyance line.

[0006]

[Patent Document 1] Japanese Patent Application Laid-Open No. 6-154
The conventional one described in Japanese Patent No. 827 is controlled by the pinch roll to reach a target pitch time within a limited time (time from when the trailing edge of the trailing material reaches the pinch roll to when it reaches the descaler). Therefore, the amount of correction / correction on the pinch roll does not expand, and it is necessary to consider so that it will always be within the correction / correction range.

That is, the above-mentioned conventional technique corrects / corrects the variation generated in the extraction and transfer line, but when the transfer time changes with the same direction of increase or decrease, the correction / correction by the pinch roll is performed. There is a problem that the range exceeds the possible range, and as a result it becomes impossible to correct or correct the target pitch time. Therefore, an object of the present invention is to provide a mill pacing method capable of coping with a change in which the transport time increases or decreases in the same direction.

[0008]

In order to achieve the above object, the present invention has taken the following means. That is, the feature of the present invention is that in a rolling line provided between the heating furnace and the rolling mill, a conveying device that controls the conveying speed of the rolled material and a detector that detects the presence or absence of the rolled material. In the mill paging method for controlling the rolling pitch between the trailing edge of the preceding rolled material and the leading edge of the trailing rolled material, the detector causes the time from the trailing edge of the preceding rolled material to the leading edge of the trailing rolled material. When To is detected and the conveying speed of the trailing rolled material of the conveying device is controlled according to a preset reference pattern based on the detection time To, after the tail end of the preceding rolled material passes through the rolling mill, The predicted inter-rolling pitch T until the tip of the trailing rolled material arrives at the rolling mill is obtained, and the predicted inter-rolling pitch T is
The point is that the extraction timing of the next rolled material is corrected by calculating the difference from the preset target rolling pitch t0 and adding the difference to the extraction timing of the next rolled material from the heating furnace.

[0009]

In the mill pacing method of the present invention, first, the pre-rolled material is extracted from the heating furnace, transported to the rolling mill by the transport device, and rolled by the rolling mill.
The trailing rolled material is extracted from the heating furnace at a predetermined timing. Then, the extracted trailing rolled material is conveyed to the rolling mill by the conveying device. At this time, the detector detects the trailing edge passage of the preceding rolled material and the trailing edge passage of the trailing rolled material to detect the detection interval time To of both.

When the conveying speed of the trailing rolled material of the conveying device is controlled based on the detection time To according to a preset reference pattern, the trailing edge of the preceding rolled material is passed after passing the rolling mill. A predicted rolling pitch T until the leading end of the rolled material reaches the rolling mill is obtained. Then, the difference between the predicted rolling pitch T and the preset target rolling pitch t0 is calculated. The calculated difference is added to the extraction timing of the next rolled material from the heating furnace to correct the extraction timing.

If the extraction timing is not corrected in this way and the extraction is performed with the extraction timing set in advance, when the transport time changes, for example, in the increasing direction, the pitch is corrected so as to be shortened every time.・ Even if corrected
When the correction / correction range is exceeded, the operation will always be continued at a pitch that is wider than the target pitch, but by correcting the extraction timing from the heating furnace as in the present invention, Enables changing the deceleration timing with pinch rolls within the correctable / correctable range.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In Fig. 3, the rolling line includes a heating furnace 1 and a rolling mill.
2, and a conveying device 3 and a detector 4 provided between the heating furnace 1 and the rolling mill 2. The heating furnace 1
Is for heating a billet 5 which is a rolled material, and the heating furnace 1 has a movable floor 6 for walking beams and a fixed floor 7 for walking beams. By repeating the rectangular motion of the walking beam movable floor 6 with respect to the walking beam fixed floor 7, the billet 5 is laterally fed in the direction of arrow A.

The carrying device 3 sends the billet 5 after heating in the lateral direction (direction of arrow B) orthogonal to the direction of arrow A. The transfer device 3 includes an in-furnace roller table 8 provided at the rear end (outgoing side) of the heating furnace 1, an out-of-furnace roller table 9 provided beside it, and a billet.
It has a pinch roller 10 that can pinch and release 5.

At least the in-furnace roller table 8 and the pinch roller 10 are forcibly driven, and the pinch roller 10
Variable speed control is possible. The detector 4
Is disposed between the pinch roller 10 and the rolling mill 2,
By detecting the tail end of the preceding rolled material 5A and the leading end of the trailing rolled material 5B, the time To from the trailing end of the leading rolled material 5A to the leading end of the trailing rolled material 5B is detected.

The rolling mill 2 has a plurality of rolling stands 2A, 2
It is a tandem rolling mill with B ... Hereinafter, the mill pacing method in the rolling line will be described. First, the total length L0n of each billet 5 and the billet tip position L1n of each billet 5 in the heating furnace 1 are measured on the inlet side of the heating furnace 1 and are tracked to the outlet side.

The extraction of the preceding billet 5A from the heating furnace 1 is started by driving the in-furnace roller table 8 of the conveying device 3. The pre-rolled material 5A extracted from the heating furnace 1 is nipped by the pinch rollers 10 and is transported while its transportation speed is controlled. This speed control is performed according to a preset reference pattern. As shown in FIGS. 1 and 2, the reference pattern is such that the pinch roller 10 is accelerated to the maximum speed VT to convey the preceding rolled material 5A, and the detector 4 detects the leading end of the preceding rolled material 5A. After the elapse of a predetermined time T1, the speed is reduced to the entry side speed VIN of the first rolling stand 2A at a predetermined deceleration rate a and the entry side speed VIN of the first rolling stand 2A.
The preceding rolled material 5A is sent to the first rolling stand 2A in synchronism with the above.

As shown in FIG. 4, the extraction start time of the next billet 5B is determined by the following equation. That is, the preceding rolled material
The time interval between the extraction start command of 5A and the extraction start command of the trailing rolled material 5B is obtained by the following equation, and the extraction start of the trailing rolled material 5B is determined.

[0018]

[Equation 1] (Extraction time interval) = (Conveyance time of preceding rolled material 5A) + (Rolling time of preceding rolled material 5A) + (Target rolling pitch t0) − (Conveying time of trailing rolled material 5B) ... (1)

Here, the conveying time of the preceding and following rolling materials 5A and 5B is the time from when the in-furnace roller table 8 starts to drive until the leading ends of the rolling materials 5A and 5B are caught in the first rolling stand 2A. Is calculated based on the speed reference pattern in consideration of the tip position L1n of the billet 5 in the heating furnace 1. Further, the rolling time of the preceding rolled material 5A is calculated in consideration of the entry speed of the first rolling stand 2A and the total length L0n of the billet 5 which change from moment to moment.

The target rolling pitch t0 is manually set by the operator in consideration of the operating condition. By the way, after starting the extraction of the preceding rolled material 5A, when the extraction of the trailing rolled material 5B is started at the time interval obtained by the above formula (1),
In some cases, the transport time and the rolling time may be different from the values used in the above decision formula (1). When the calculation and the actual operation thereafter are different, the pitch between rollings is different from the target value t0. Therefore, this difference is corrected as shown in FIGS.

In FIGS. 1 and 2, the detector 4 detects the time To from the trailing edge of the preceding rolled material 5A to the leading edge of the following rolled material 5B. Based on this detection time To, when the conveying speed of the pinch roller 10 is controlled by the preset reference pattern, the trailing edge of the preceding rolling material 5A passes through the first rolling stand 2A, and then the following rolling material 5B. Predicted rolling pitch T until the leading edge of 1 reaches the first rolling stand 2A is obtained.

That is, as shown in FIGS. 1 and 2, the predicted rolling pitch T is obtained by the following equation.

[0023]

## EQU2 ## T = To- [T1.VT + {(VT + VIN). (VT-VIN) / 2a)}-VIN. {((VT-VIN) / a + T1}] / VIN ... (2) where , VT: Maximum speed of the pinch roller 10 VIN: Speed on the entry side of the first rolling stand 2A T1: Timing of deceleration of the pinch roller 10 (Time from detector 4 detecting the tip of trailing rolled material 5B to deceleration) ) a: Deceleration rate of pinch roller 10 (the time required to decelerate from speed VT to VIN is (VT-VIN) / a)

(T1.VT) in the above equation (2)
Represents the distance that the trailing material 5B is conveyed at the speed VT after the tip of the trailing material 5B reaches the detector 4, {(VT + V
IN). (VT-VIN) / 2a)} is the speed from the speed VT to the speed V after the tip of the trailing material 5B reaches the deceleration timing T1.
Indicates the distance that the trailing material 5B is transported while being decelerated to IN,
VIN · {((VT −VIN) / a + T1} indicates that the trailing member 5B has a velocity V after the tip of the trailing member 5B reaches the detector 4.
While the deceleration from T to speed VIN is completed, the preceding material 5A moves to speed V
Indicates the distance transported at IN.

Then, the difference (T-t0) between this predicted rolling pitch T and the preset target rolling pitch t0 is calculated, and the reference pattern is changed so that this difference becomes zero. Consider this change as follows. That is, assuming that the deceleration timing T1 is changed to T1 + ΔT in order to make the difference zero, the term of (T1VT) in the equation (2) is changed to ΔT (VT-VI) by the modification of the deceleration timing.
N) will be transported extra.

Therefore, the following equation holds.

[0027]

[Equation 3] ΔT · (VT −VIN) / VIN + ΔT = T−t0 …… (3) ∴ΔT = (T−t0) · VIN / VT

That is, the deceleration timing T1 of the reference pattern
To

[0029]

## EQU4 ## If the change is made to T1 + (T-t0) .VIN / VT (4), the difference becomes zero.

However, by controlling the pinch roller 10 with this changed reference pattern, the pitch between rollings can be set to the target value t0. By the way, even if the above-mentioned control is performed, a phenomenon occurs in which the pitch between rollings is slightly deviated from the target value t0. This "deviation" is not irregular,
It is empirically clear that it appears with a certain directionality. The cause of the "deviation" is adjustment of the roll gap of the rolling mill 2, wear of pinch rolls, change of billet size, and the like.

Therefore, in order to correct the above "deviation", the extraction timing is corrected in the present invention.
That is, the difference (T-t0) between the predicted rolling pitch T and the preset target rolling pitch t0 is added to the extraction timing of the next rolled material, and the extraction timing is corrected.

That is, for example, when T-t0 <0, the deceleration timing is extracted earlier by the amount corresponding to the earlier deceleration timing. The present invention is not limited to the above embodiment.

[0033]

According to the present invention, the pitch between rollings can be maintained at the target value and the productivity is not deteriorated.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a concept of a mill pacing method according to the present invention.

FIG. 2 is a flowchart showing an embodiment of the present invention.

FIG. 3 is a configuration diagram showing a configuration of a rolling line used in an example of the present invention.

FIG. 4 is an explanatory diagram of an extraction pitch of rolled material.

[Explanation of symbols]

 1 Heating Furnace 2 Rolling Machine 3 Conveying Device 4 Detector 5 Rolling Material (Billet)

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location 8315-4E B21B 37/00 136B

Claims (1)

[Claims] 1. A trailing edge of a preceding rolling material in a rolling line provided with a conveying device for controlling the conveying speed of the rolled material and a detector for detecting the presence or absence of the rolled material between the heating furnace and the rolling mill. In the mill paging method for controlling the rolling pitch between the trailing rolled material and the trailing rolled material tip, the detector detects a time To from the trailing edge passage of the preceding rolled material to the leading edge passage of the trailing rolled material, When the conveying speed of the trailing rolled material of the conveying device is controlled based on the detection time To according to a preset reference pattern, the leading end of the trailing rolled material passes after the tail end of the preceding rolled material passes through the rolling mill. Of the predicted rolling pitch T until the steel sheet arrives at the rolling mill, the difference between the predicted rolling pitch T and the preset target rolling pitch t0 is calculated, and the difference is calculated from the heating furnace for the next rolled material. By adding to the extraction timing, the next rolled material Mill pacing method characterized by modifying the extraction timing.