JPH09276912A - Method for controlling mill pacing in hot rolling line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely catch up the front tip part of a following material to the rear end part of a preceding material to realize joining by controlling the ejecting time of a heating furnace based on a rolling schedule and a transporting pattern and further, adjusting finish rolling speed. SOLUTION: A slab as the following material heated to a prescribed temp. in a heating furnace 1, is rolled into a bar with a rough-rolling mill group 2 and coiled into a two position type coil box 3. Thereafter, the bar uncoiled from this coil box is joined with the preceding material with a self-travelling type joining machine 4 and endless-rolled with a finish-rolling mill group 5 and the obtd. rolled material is cut off to a prescribed length with a shear 6 and coiled to a coiler 7. At the time of controlling a mill pacing to this hot- rolling line without looper, the ejecting time from the heating furnace is controlled so that arrival times to joining start position of the rear end part of the preceding material and the front tip part of the following material predict- calculated based on the rolling schedule and the traveling pattern equalize. Further, the finishing speed of the preceding material is adjusted base on the position and speed of the rear end part of the preceding material during finish- rolling and the schedule of the uncoiled speed of the following material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mill pacing control method in a hot rolling line.

[0002]

2. Description of the Related Art In endless rolling for finishing, a self-propelled joining machine upstream of a finishing rolling machine is used to perform bar joining between runs. The self-propelled joining machine exists between the coil box located downstream of the rough rolling mill and the finish rolling mill, and runs from the coil box side to the finish joining section at a speed that is synchronized with the preceding material being finish rolled. Meanwhile, the bar joining of the trailing edge of the preceding material and the leading edge of the following material is performed.

Before the bar joining is started, the joining machine stands by at the joining starting point which is the most upstream point of the joining section. To join, the tail end of the preceding material during finish rolling is joined to the joining starting point. Before passing through, the tip of the trailing material unwound from the coil box must catch up with the tail of the preceding material.

Conventionally, for example, in a continuous line such as a cold rolling line, since the plate thickness is thin, it is possible to sufficiently bend the steel slab, and when welding the preceding material and the following material, a looper is used. It was possible to adjust the tail edge speed of the preceding material by using such equipment, and to easily make the trailing edge of the following material catch up with the trailing edge of the preceding material and perform welding.

[0005]

However, in hot rolling, the bar before finish rolling has a large plate thickness and cannot sufficiently bend the steel plate, so that equipment such as a looper cannot be applied. For this reason, it is difficult to surely make the trailing edge of the trailing material catch up with the tail edge of the preceding material to realize the joining just before the joining start point.

The present invention aims to solve this problem,
An object of the present invention is to provide a means for reliably joining a leading edge of a trailing material to a trailing edge of a preceding material just before a joining start point in a hot rolling line to which equipment such as a looper cannot be applied.

[0007]

According to the present invention, the above-mentioned problems are solved from the heating furnace extraction to the preset joining start position based on the preset rolling schedule and conveyance pattern of the material to be rolled. Predictively calculate the time required to reach the leading edge of the preceding material and the time required to reach the leading edge of the following material, and heat so that the arrival time of the leading material tail end and the arrival time of the trailing material tip end at the joining start position are equal. While calculating the extraction time of the trailing material from the furnace, outputting the extraction instruction of the trailing material at the extraction time, and winding the trailing material in the coil box,
Based on the position and speed of the trailing edge of the preceding material during finish rolling and the unwinding speed schedule from the coil box of the trailing material, the arrival time of the trailing edge of the preceding material to the joining start position and the arrival time of the leading edge of the following material. Is calculated again, the finishing speed of the preceding material at which the joining start position passing time of the leading material is equal to the joining starting position passing time of the trailing material tip is calculated, and the finishing speed change command is output. This is accomplished by providing a mill pacing control method that

Further, the operation procedure of the present invention will be described with reference to FIG. [Step 1] Based on a preset rolling schedule and conveyance pattern of the material to be rolled, it is necessary to reach the tail end of the preceding material and the leading end of the following material from the heating furnace extraction to the preset joining start position. Predict each time.

[Step 2] From the actual extraction time of the preceding material and the predicted arrival time of the tail end of the preceding material from the heating furnace extraction to the joining start position, the predicted arrival time of the joining start position of the tail end of the preceding material is obtained.

[Step 3] From the predicted arrival time of the joining start position of the trailing edge of the preceding material and the estimated arrival time from the extraction of the heating furnace of the trailing material tip to the arrival of the joining start position, the tail end of the preceding material to the joining start position is calculated. The extraction time of the trailing material from the heating furnace is calculated so that the arrival time is the same as the arrival time of the trailing material tip.

[Step 4] At the extraction time obtained in step 3, a subsequent material extraction command is output.

[Step 5] With the trailing material wound up in the coil box, the position and speed of the trailing edge of the leading material during finish rolling and the shortest unwinding schedule of the trailing material from the coil box are used as described above. The arrival time Ts of the leading edge of the preceding material and the arrival time Tk of the leading edge of the following material at the joining start position are predicted and calculated.

[Step 6] The predicted joining time arrival time Ts of the trailing edge of the preceding material obtained in step 5 is compared with the predicted arrival time Tk of the joining start position of the leading edge of the following material, and it is necessary to change the finishing speed of the preceding material. The presence or absence of is determined. If Ts is the time after Tk, the trailing material tip can catch up with the trailing edge of the preceding material upstream of the joining start point, so that there is no need to change the finishing speed of the preceding material, and the processing ends. If Ts is earlier than Tk, the trailing material tip cannot catch up with the trailing edge of the preceding material upstream from the joining start point, so it is necessary to change the finishing speed of the preceding material, and the process proceeds to step 7. Proceed.

[Step 7] The finishing speed of the preceding material is calculated so that the time required for the tail end of the preceding material to reach the joining start position is Tk.

[Step 8] A finishing speed change command to the finishing speed obtained in step 7 is output.

In this way, in the present invention, in a hot rolling line to which equipment such as a looper cannot be applied, just before the joining start point, the trailing edge of the trailing material surely catches up with the tail edge of the preceding material to realize the joining. To do.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a mill pacing control method in a hot rolling line according to the present invention will be described below. FIG. 1 shows a general hot rolling line for finishing endless rolling and a mill pacing control computer 8 for carrying out the present invention.

The slab is extracted after being heated to the target temperature in the heating furnace 1. After that, it is rolled into a bar by the rough rolling mill group 2 and is once wound by the coil box 3. afterwards,
After being unwound from the coil box 3 and joined to the tail end of the preceding material being finish-rolled by the joining machine 4, it is endless-rolled by the finish rolling machine 5. The finish-rolled plate is cut into a predetermined coil length by the shear 6 in front of the coiler 7 and then wound by the coiler 7.

The coil box 3 is of a two-position type. At the upstream position, the following material is wound after the rough rolling is completed, and at the downstream position, the preceding material is unwound to the finish rolling mill. . The succeeding material, which has been completely wound at the downstream position, is unwound at the upstream position after the unwinding of the preceding material is completed and the downstream position becomes empty. Thereafter, the following material is transferred to the downstream position by the coil transfer mandrel while being unwound. After the succeeding material has been transferred to the downstream position and the upstream position has become empty, the next rolled material can be wound onto the upstream position.

The joining machine 4 is a self-propelled type, and before joining is started,
Waiting at the welding start point, which is the most upstream point of the welding section,
While traveling in a predetermined joining section from the coil box side to the finish at a speed synchronized with the preceding material being finish-rolled, the bar joining between the tail end of the preceding material and the leading end of the following material is performed. 8 is the material to be rolled,
This is a mill pacing control computer that tracks and controls each facility.

FIG. 3 is a characteristic diagram showing planned transport patterns and actual transport patterns for the trailing edge of the leading material and the leading edge of the trailing material. When the preceding material is extracted from the heating furnace, first, from the preceding material extraction time T0 and the predicted conveyance pattern Ps0 of the preceding material tail end, the joining start position arrival time T of the preceding material tail end is reached.
3 is predicted. Then, based on the predicted conveyance pattern Pk0 of the trailing material tip, the heating furnace extraction time T1 of the trailing material is set so as to arrive at time T3 at which the leading edge of the trailing material reaches the joining start position.
Is calculated, and the trailing material is extracted at time T1.

However, the predicted transport pattern Ps0 of the trailing edge of the preceding material and the predicted transport pattern Pk0 of the leading edge of the following material have an error with the actual transport pattern Ps1 of the trailing edge of the preceding material and the actual transport pattern Pk1 of the trailing material. Therefore, at the time T2 when the trailing material is roughly rolled and winding on the coil box is completed, the arrival time T at the joining start position of the tail end of the preceding material is reached.
The time T4 for reaching the joining start position of 3'and the trailing material tip is calculated again. At this time, if T4 is delayed by Δt from T3 ', if the rolling is continued as it is, the joining becomes impossible, so that the arrival time of the tail end of the preceding material to the joining start position is T4.
The finishing speed of the preceding material during finish rolling is changed so that

[0023]

As described above, according to the present invention,
Even in a hot rolling line to which equipment such as a looper cannot be applied, the trailing material can be made to catch up with the preceding material at the joining start position, and the joining can be performed reliably from the joining start position. As a result, the joining is stable, and it is possible to prevent the occurrence of troubles at the time of joining failure and the stoppage of the operation due to this, and it is possible to stabilize the endless rolling operation.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of a hot rolling line to which the method of the present invention is applied.

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

FIG. 3 is a characteristic diagram showing a conveyance pattern of a material to be rolled when the present invention is applied.

[Explanation of symbols]

 1 heating furnace 2 rough rolling mill group 3 coil box 4 joining machine 5 finishing rolling mill group 6 shear 7 coiler 8 mill pacing control computer

Claims (1)

[Claims] 1. A mill pacing control in a hot rolling line that has a coil box and a joining machine between a rough rolling mill and a finish rolling mill, and joins bars after rough rolling in the joining machine to perform endless rolling for finishing. Based on a preset rolling schedule and conveyance pattern of the material to be rolled, the time required for the tail end of the preceding material to reach the preset joining start position from the heating furnace extraction and the arrival of the trailing material tip are set. Prediction calculation of the required time, calculate the extraction time of the trailing material from the heating furnace so that the arrival time of the leading material tail end and the arrival time of the trailing material tip to the joining start position are calculated, and the extraction is performed. At the same time as outputting the extraction command of the trailing material, the position and speed of the trailing edge of the leading material during finish rolling and the unwinding speed of the trailing material from the coil box while the trailing material is wound in the coil box Schedule Based on the rule, the arrival time of the trailing edge of the preceding material and the arrival time of the trailing edge of the trailing material at the joining start position are predicted and calculated again, and the joining start position of the trailing edge of the leading material passes through A mill pacing control method in a hot rolling line, which calculates a finishing speed of a preceding material that is equal to a position passing time and outputs a finishing speed change command.