JP2011245508A - Method of operating hot-rolled coil yard - Google Patents

Abstract

A simple and rational method for operating a coil yard is provided.
In a hot rolled coil yard, the coil payout time of the scheduled payout section is compared with the scheduled cooling completion time set for each coil, and the coil payout time has passed the expected cooling completion time. A method of operating a hot-rolled coil yard is characterized in that the coil is discharged from the hot-rolled coil yard in order from the coil with a smaller coil weight.
[Selection] Figure 1

Description

  The present invention relates to a method of operating a hot rolled coil yard.

Usually, in the hot rolled coil after completion of hot rolling, the bundling material that is bundled as it is and shipped as a product, and one or more of skin pass, shear, slitter, pickling line, etc. as the next process And the next process material that passes through the line.
A coil place that temporarily stores the hot-rolled coil and cools it to a predetermined temperature and a coil place (warehouse) that performs a buffer function for adjusting the cycle of the next process are called a coil yard.

  For example, in the case of a skin pass material that is one of the next process materials, the hot rolling coil is lightly reduced by about 0.1 to 3.0% in the skin pass line, and is uniformly expanded to obtain a predetermined amount. Although flatness can be obtained, the coil temperature must be lowered to 40 to 60 ° C. or lower. Therefore, in general, the skin pass material is carried out to the skin pass line after the set scheduled cooling completion time has elapsed in the coil yard (hereinafter referred to as “dispensing”).

  However, when a high-temperature coil having a temperature of 400 to 900 ° C. immediately after rolling is carried into the coil yard (hereinafter referred to as “distribution”), if the skin pass material is placed near the completion of cooling or in the vicinity of the cooled skin pass material, The temperature rises again due to the heat radiation from the high temperature coil, and a cooling wait (loss) occurs until the temperature is lowered to the skin pass processable temperature again.

  In addition, the longest waiting time (in-process time) of coil products is waiting for cooling in the coil yard. For example, in the case of the above skin pass material, the cooling waiting time in the summer in the coil yard is approximately 3 to 5 days. It becomes. Therefore, various measures have been taken to cool down in a shorter time in order to shorten the process waiting time. As hardware measures, promotion of natural ventilation in the hot rolled coil yard building itself, elevated floor of the hot rolled coil stand There are promotion of draft effect by formulating, forced air cooling of hot-rolled coil by fan or the like. Moreover, as a soft countermeasure, there is an improvement in an efficient method for distributing hot-rolled coils in the coil yard and other coil yard operating methods (Patent Document 1).

Japanese Patent Publication No.55-10325

  According to the technique of Patent Document 1, since the temperature difference between the already distributed coil and the coil immediately after rolling is small, the periphery of these coils is kept at a high temperature, so it is necessary to increase the coil cooling time. The coil yard residence time of the hot rolled coil tends to be long, and there is a difficulty in the efficient operation of the coil yard. Therefore, an object of the present invention is to provide a simple and rational method for operating a coil yard.

  The present invention is an invention that focuses on a method for discharging a hot-rolled coil from a coil yard. In addition, it is a linked operation method in relation to the next process, rather than an operation method that is completed only by the coil yard.

  That is, in order to avoid the occurrence of cooling waiting due to incomplete cooling in the coils constituting each subsequent process cycle, the coil discharge from the coil yard to the next process is sequentially performed from the coil single weight, that is, the coil having a small heat capacity. The essence lies in paying off to the process line.

  This means that in the coil cooling process, even if there is some disturbance factor such as heat radiation when a high-temperature coil immediately after rolling is brought into the yard, the coil temperature is lowered to an allowable temperature or lower with a higher probability. This means that the coil single weight with a high probability of being relatively high temperature, that is, the coil with a large heat capacity, can substantially increase the cooling time by the order in which the next process is performed later. means.

  By this operation, it is possible to avoid stopping the next process, particularly the skin pass line, while waiting for cooling of the hot-rolled coil. This means that it is possible to avoid a decrease in the pitch of the hot rolled coil into the coil yard, that is, it is possible to avoid a decrease in the production pitch of the hot rolled coil.

  The gist of the present invention is as follows.

  According to a first aspect of the present invention, in the hot-rolled coil yard, the coil delivery time is compared with the coil completion time set for each coil by comparing the time with the scheduled cooling completion time set for each coil. In the hot rolled coil yard operating method, the coils having passed through are sequentially discharged from the hot rolled coil yard in order from the coil having a small coil weight.

  2nd invention is the operation method of the hot rolling coil yard as described in 1st invention which implements a next process process sequentially from a coil with small coil single weight in forming a next process process cycle. .

  3rd invention arrange | positions the hot coil after hot rolling away from the coil place which adjoins diagonally right and left of the coil which the scheduled completion time of cooling passed, and diagonally, It is characterized by the above-mentioned. This is a method of operating a hot rolled coil yard.

  By using the operation method of the hot-rolled coil yard of the present invention, it is possible to avoid the next process, in particular, stopping the skin pass line waiting for cooling of the hot-rolled coil.

It is a figure explaining the order of the coil applied to a next process process. It is a figure explaining one embodiment of the present invention. It is a figure which shows an example of the coil cooling curve after coil winding. It is a figure which shows an example of the coil cooling time management table | surface by a coil single weight division and a width division. It is a figure explaining the balance relationship of the number of coils of the coil yard in specific time. It is a figure explaining the adjacent positional relationship of a coil. It is a figure explaining the reheating by thermal radiation when the high temperature coil just after rolling is placed in the adjacent position of the coil near the completion of cooling. It is a figure explaining an example of a coil, a coil stand, and a temperature sensor.

  Hereinafter, an example of the best mode for carrying out the present invention will be described.

  A coil temperature cooling curve as shown in FIG. 3 is obtained in advance by heat dissipation calculation or actual measurement from several patterns of hot-rolled coil having different winding temperature, unit weight, shape, material, and the like. In order to set the cooling completion scheduled time of the hot-rolled coil actually manufactured based on this cooling curve, the larger the number of patterns, the better. This is because, based on these patterns, the cooling curves of various coils that are not in the pattern are complemented and the scheduled cooling completion time is determined, so that the accuracy of the scheduled cooling completion time increases as the number of patterns serving as the original data increases.

With the above preparation, it is possible to set a scheduled cooling completion time for each coil distributed to the coil yard. For example, FIG. 4 is a coil cooling time management table by the coil single weight section and the width section.
From this table, for example, coil width _L 1 ~L _2, the coil unit weight _W 1 to _W-2 in the range of the coil is found to be complete cooling from the winding ₂₂ hours after _t. Actually, it is necessary to prepare the data in consideration of the influence of differences in coil winding temperature, ambient temperature, etc., but this table makes it possible to estimate the cooling completion time of each coil.

In general, since coil distribution to and delivery from the coil yard is performed by a crane, as shown in FIG. 5, the number of distributions in the coil yard is z (the maximum number of placements is z ₀ ). The ratio of the number of distributions per hour x / Hr and the number of payouts y / Hr is often about several percent.

  Accordingly, although the number of coils that are scheduled to complete cooling or the number of coils that have passed the time changes from time to time among z pieces, if there are more than y pieces at a specific coil payout time, the coil that has been cooled is not discharged for a larger amount. It stays in the yard, which means a decrease in the operating efficiency of the coil yard.

On the other hand, in order not to reduce the operation efficiency of the coil yard, if the operation basically satisfies xy ≦ 0, the operation efficiency of the coil yard due to the occurrence of insufficient storage space (z−z ₀ > 0) is reduced. Decrease can be avoided.

  Hereinafter, a method for efficiently operating the coil yard will be described in detail.

  As shown in FIG. 1, at a specific coil payout time, among the coils that have been scheduled for completion of cooling set for each coil or have passed that time, the coils are discharged from the coil yard sequentially from the coil with the smallest coil weight. In the coil group that constitutes one cycle, the coil unit weight, that is, the coil having the smaller heat capacity, is discharged to the next process line in order.

  In other words, even if there are various disturbance factors in the coil cooling process, this is nothing but the probability that the coil temperature is lowered to a temperature lower than the allowable temperature with a higher probability, and the probability of being relatively high. High coil single weight, that is, a coil with a large heat capacity, means that the order in which the next process is performed is behind, which means that it can substantially increase the cooling time. Therefore, as a result, the next process can be continuously performed with a high probability without stopping in the waiting for cooling, and it is simple and rational.

There is a next process with temperature constraints. For example, in the case of the above skin pass, the coil temperature needs to be lowered to 40 to 60 ° C. or lower. Here, T _loss (coil moving time, etc.) is necessary for the inevitable loss time required for the skin pass processing after the first skin pass material is paid out from the coil yard, and the average skin pass processing execution time per coil is represented by t _s , 1 When coils constituting the cycle is n, the waiting time T _i of the coil to be processed i-th,
T _i = T _loss + (i−1) _ts
It becomes. The coil temperature continues to decrease during this waiting time, and can be considered as part of the coil cooling time. Therefore, in order to effectively use the T _i when Crossed next step processing cycle, when Crossed same next step processing cycle from the payout coils sequentially from the coil unit weight of small coils, if carried out following step process, substantial You will earn more cooling time.

As shown in FIG. 6, in the coil yard, when attention is paid to a certain coil 1, a maximum of eight coils are placed around the coil 1 in the same plane. Here, assuming that the coil 1 is close to completion of cooling or has been cooled, when the high-temperature coil immediately after rolling is arranged in the surrounding storage spaces Z _{1 to} Z ₈ , the temperature of the coil 1 is changed from the high-temperature coil as shown in FIG. The temperature rises again due to heat radiation, and the temperature is not yet cooled. In particular, when the high temperature coil is placed in the yards Z ₂ and Z ₇ where the coil side surfaces 2 face each other, the temperature increase is larger. Therefore in order to avoid the disturbance occurrence on the coil yard operational as coil again heating it is to avoid with distribution of hot coil around Z ₁ to Z ₈ of the coil 1. If there is absolutely no coil place, it is better not to place at least high temperature coils in the places Z ₂ and Z ₇ . However, the coil 1 should be paid out as soon as the cooling completion time is reached.

  In general, the coil is placed on the coil mount 3 as shown in FIG. 8 in order to prevent the coil from toppling and rolling and to ensure the accuracy of the coil installation position. Thus, the actual coil temperature can be monitored, and coil temperature management can be performed more reliably. In addition to this temperature monitoring, if the high-temperature coil immediately after rolling is not placed in the surrounding area of the coil that has been cooled (finally determined by the temperature sensor) as described above, it can be re-established by heat radiation from the high-temperature coil. The occurrence of disturbance in coil yard operation such as temperature rise can be avoided, and the coil yard can be operated more reliably.

FIG. 2 shows an embodiment of the present invention. The present invention was implemented in the summer because the hot rolling efficiency reduction due to clogging of the coil place and the occurrence of a loss in waiting for the next process are common in the summer when the temperature is high. Number of coil places Z ₀ = 1200 (1 coil / place 1), coil filling rate target Z / Z ₀ = 90%, distribution and discharge pace x = y ≒ hot rolling efficiency ≒ 600t / Hr pace (coil average If the unit weight is 20 t / piece, 30 pieces / Hr).

  The coil for which the hot rolling process was completed was carried and placed in the coil yard with a crane or the like. At that time, the arrangement position was not particularly taken into consideration, and it was appropriately arranged at an empty position. In addition, the coil cooling time was uniformly set to 4 days regardless of the winding temperature, dimensions, unit weight, etc. of each coil. This means that it is possible to pay out from the coil yard after 96 hours have passed from the hot rolling completion time, and the coil yard management on the system is very simple.

  First, the payable coil was discharged from the coil yard from a coil having a small coil weight. And also when combining a cycle according to next process from these coil groups, as shown in FIG. 1, it processed from the coil with small coil single weight.

  As a result, it was possible to reduce the hot rolling efficiency and the waiting time for the next process due to clogging of the coil place, which had been generated several times a month, especially in the summer.

DESCRIPTION OF SYMBOLS 1 Coil 2 Coil side surface 3 Stand 4 Temperature sensor

Claims (3)

  In the hot rolling coil yard, the coil payout time of the scheduled payout section is compared with the coil completion time set for each coil and the coil payout time has passed the expected cooling completion time. A method of operating a hot-rolled coil yard, characterized in that the coil with a small coil weight is sequentially discharged from the hot-rolled coil yard.   2. The method of operating a hot rolled coil yard according to claim 1, wherein in forming the next process processing cycle, the next process is sequentially performed from a coil having a small coil weight.   The hot-rolled coil yard according to claim 1 or 2, wherein the hot-rolled coil yard after hot rolling is disposed away from a coil place adjacent to the front, rear, left, right, and diagonally of the coil after the scheduled completion time of cooling. Operation method.