JP2012166243A - Conveyance control method for rolled material in hot rolling line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveyance control method for a rolled material in a hot rolling line capable of minimizing the idling time between rolled materials at an inlet side of a finishing rolling mill even though errors on the rolling time may be generated in a rough rolling mill.SOLUTION: When errors at the actual rolling time are generated on material rolling starting and terminating times of respective stands R1 to R3 set at the time of sampling in a heating furnace 1, the pitch can be corrected by changing the conveyance speed of conveyance tables among the stands R1 to R3 so as to make next stand R2 or R3 located at a downstream side start its rolling at an originally set time.

Description

  The present invention relates to a method for controlling the conveyance of a rolled material in a hot rolling line.

  In order to increase the production efficiency in hot rolling, methods such as improving the prediction accuracy of the conveyance time in mill pacing are performed (for example, see Patent Document 1). In addition, when the finish rolling mill entry side is behind the predicted time, a method of waiting the material between the stands in the upstream rough rolling mill is also performed (for example, see Patent Documents 2 and 3). Furthermore, in order to improve the efficiency, a method of controlling the material conveyance speed on the finishing rolling mill entrance side is also performed so as to minimize the pitch margin (idle time) (for example, see Patent Document 4).

JP 2004-25245 A Japanese Patent Laid-Open No. 4-182018 JP-A-6-299231 JP 2006-51526 A

  However, in order to increase the production efficiency in the hot rolling as shown in Patent Document 1, in the method of improving the prediction accuracy of the conveyance time in the mill pacing, the operation change after the heating furnace extraction, for example, the finishing speed by the temperature control, the acceleration When a rate change or the like occurs, there is a problem that a rolling time difference occurs with the following material, and when it is early, material collision occurs, and when it is late, idle time increases and production efficiency does not increase. In order to compensate for this, as in Patent Document 2, the method for preventing collision with the preceding material, and as in Patent Document 3, the finish rolling mill arrival time is set in the heating furnace extractor and the roughing mill stand group. A method of feeding back to the material has been proposed. However, since it is a method of delaying the conveyance, an improvement in production efficiency cannot be achieved. In order to improve the production efficiency, as in Patent Document 4, there is also a method for minimizing the idle time by reducing the conveying speed after preventing the collision with the preceding material for the rolled material on the finishing rolling mill entrance side. However, it is the rolled material that exists on the finishing mill entry side that can fulfill this function, and it is not possible to expect an improvement in production efficiency for the rolled material that already exists in the stand group of the rough rolling mill.

  The present invention has been made in view of the above, and even when an error occurs in the rolling time in the rough rolling mill, it is possible to minimize the idle time between the rolled materials on the finishing rolling mill entrance side. It aims at providing the conveyance control method of the rolling material in the hot rolling line which can be performed.

  In order to solve the above-described problems and achieve the object, a method for controlling the conveyance of a rolled material in a hot rolling line according to the present invention includes a heating furnace, a rough rolling mill having a plurality of stands, and a heat provided with a finish rolling mill. In the method for controlling the transport of rolled material in the inter-rolling line, if an error occurs during actual rolling with respect to the material rolling start time and end time of each stand set during extraction of the heating furnace, transport of the transport table between the stands By changing the speed, the pitch is corrected so that the next stand on the downstream side starts rolling at the initially set time.

  Moreover, the conveyance control method of the rolling material in the hot rolling line according to the present invention is that, in the above-described invention, the conveyance table between the stands is basically operated at a conveyance speed of about 80% of the maximum conveyance speed. Features.

  According to the present invention, when an error occurs during actual rolling with respect to the material rolling start time and end time of each stand set at the time of extraction of the heating furnace, by changing the transport speed of the transport table between the stands, In the next stand on the side, the pitch is corrected so that rolling is started at the initial setting time, so even if an error occurs in the rolling time in the roughing mill, the rolling material on the finishing mill entry side The idle time can be minimized, and furthermore, the rolled material can be maintained at a predetermined temperature on the finishing mill entry side.

FIG. 1 is an explanatory diagram showing a schematic configuration of the hot transfer line of the present embodiment and an outline of transfer time calculation at the time of heating furnace extraction. FIG. 2 is an explanatory diagram illustrating a method for changing the conveyance speed according to the present embodiment. FIG. 3 is a schematic flowchart showing a generalized control method according to the present embodiment.

  Below, an embodiment of a conveyance control method of a rolling material in a hot rolling line concerning the present invention is described in detail based on a drawing. Note that the present invention is not limited to the embodiments.

  FIG. 1 is an explanatory diagram showing a schematic configuration of the hot transfer line of the present embodiment and an outline of transfer time calculation at the time of heating furnace extraction. As shown in the upper part of FIG. 1, the hot conveyance line includes a heating furnace 1, a rough rolling mill 2 having a plurality of stands R <b> 1 to R <b> 3, and a finish rolling having a plurality of stands F <b> 1 to (usually 7 bases). It is comprised from the machine 3, the winding machine which is not shown in figure, the conveyance table etc. which are not shown in figure which conveys a rolling material between these facilities.

  In such a configuration, at the time of extraction of the rolling material heating furnace, the conveyance schedule, that is, each of the rough rolling mill 2 is set so that the minimum necessary idle time (time necessary for positioning the equipment) is obtained without colliding with the preceding material. The rolling start time and end time of the stands R1, R2, R3 are determined. That is, in FIG. 1, as shown in the middle stage, when extracting the heating furnace of this material, the conveyance time calculated by the predetermined conveyance / rolling speed of the material is obtained (see the lower part of FIG. 1), The minimum idle time, that is, the time necessary for positioning the equipment is added to determine the transport time of the material.

  Next, after extracting the material heating furnace, the difference between the actual speed when reaching the respective stands R1, R2, R3 of the rough rolling mill 2 and the set time is calculated. In order to eliminate the difference, the transport speed of the transport table transported to the next stand R2 or R3 positioned downstream is determined, the transport speed is changed, and the initial setting is set for the next stand R2 or R3 on the downstream side. The pitch is corrected so that rolling starts at the time. At this time, if the changed transport speed of the transport table becomes maximum, an error occurs in the next stand R2, and therefore compensation is performed at the transport speed up to the next stand R3. The transport table between the stands R1, R2 and R3 is basically operated at a transport speed slightly lower than the maximum transport speed (about 80%), and it has a margin for deceleration and acceleration with respect to the positive / negative difference from the set time. Is given. Further, in the present embodiment, the minimum value of the idle time used as a reference is the time on the finishing rolling mill 3 entry side, and if a difference from the set value occurs here, each stand R1, the difference of the difference is generated. Accumulation of errors can be eliminated by adding to the rolling start time and end time of R2 and R3.

  FIG. 2 is an explanatory diagram illustrating a method for changing the conveyance speed according to the present embodiment. In FIG. 2, the actual time is obtained from the time when the material arrives at the stand R2 of the rough rolling mill 2, and the difference from the set time is obtained. When reaching the next stand R3 in the rough rolling mill 2, the rolling speed and the transport speed of the transport table of the stand R2 are changed by the difference so that the set time is reached. In the illustrated example, since the arrival time at the stand R2 is delayed, the rolling speed and the conveying speed of the conveying table of the stand R2 are increased, and the pitch is corrected so that rolling is started at the initial setting time in the next stand R3 on the downstream side. It shows how they are doing. Thereby, it is possible to minimize the gap between the rolling materials on the entry side of the finishing mill 3 (idle time), and to maintain the rolling material on the entry side of the finishing mill 3 at a predetermined temperature.

  FIG. 3 is a schematic flowchart showing a generalized control method according to the present embodiment. The conveyance time is calculated based on the extraction of the preceding material, and the conveyance time of the material is calculated based on this calculation and the extraction of the material. And No. which has started rolling processing. The transport time error between the i stand and the transport time is calculated, the transport speed is recalculated so as to eliminate this error, and the changed transport speed is set. Similarly, the next No. starting the rolling process. An error of the transfer time with respect to the transfer time of the i + 1 stand is calculated, the transfer speed is recalculated so as to eliminate this error, and the changed transfer speed is set. Such a process is repeated in the same manner for all the stands disposed from the roughing mill 2 entry side to the roughing mill 2 exit side. That is, the difference from the set time is compensated for in all the stands of the rough rolling mill 2.

DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Rough rolling mill 3 Finish rolling mill R1-R3 Stand

Claims (2)

In the conveyance control method of rolled material in a hot rolling line equipped with a heating furnace, a rough rolling mill having a plurality of stands, and a finish rolling mill,
When an error occurs during actual rolling with respect to the material rolling start time and end time of each stand set at the time of extraction from the heating furnace, the downstream next stand is changed by changing the transport speed of the transport table between the stands. Then, the conveyance control method of the rolling material in the hot rolling line, wherein the pitch is corrected so that rolling is started at the initial set time.   The conveyance control method for rolled material in a hot rolling line according to claim 1, wherein the conveyance table between the stands is based on operation at a conveyance speed of about 80% of the maximum conveyance speed.

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