JPH1190515A - Method for storing stock slab, method for preparing rolling order of slab and method for heating slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce feeding fuel to slabs in which hot charged slabs and stock slabs coexist and also to enable rapid decision of rolling order. SOLUTION: The hot charged slabs which are directly charged into a continuous heating furnace and stocked slabs which are stored in a storage yard are divided into groups within the range where continuous rolling is possible. The rolling order of the hot charged slab HCR is decided in the unit of group (S2, S3) and, when the hot charged slabs belong to a certain group are charged into the continuous heating furnace for hot charged stabs according to the rolling order, the rolling order of the stock slabs belong to the same group as the group are detected so that the extracting times of all hot charged slabs belong to the group and the extracting times of the stock slabs CCR which are char ed into a continuous heating furnace for stock slabs become simultaneous.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of storing stock slabs of various sizes stored in a storage yard, and a direct-feed slab directly supplied from a continuous casting machine to a continuous heating furnace in a process before rolling a steel product. The present invention relates to a method for preparing a rolling order when the steel stock and the stock steel slab are mixed and a method for heating the steel slab.

[0002]

2. Description of the Related Art In a steel product manufacturing process, in a hot rolling process which is a process subsequent to a continuous casting process, a slab is charged into a continuous heating furnace according to a predetermined rolling order, and heated to a predetermined temperature. This is a step of extracting and rolling this steel slab to a target size. The continuous heating furnace is a heating furnace of a type in which steel slabs are sequentially charged from a charging inlet and are sequentially extracted from an extracting port. As the type of the billet, there is a direct-feed billet (hereinafter, sometimes referred to as HCR) which is directly charged into a continuous heating furnace without being stored in a storage yard after casting by a continuous caster, and temporarily stored. Stock slabs (hereinafter sometimes referred to as CCR) stored in a yard (slab yard) at room temperature and then charged into a continuous heating furnace are usually used. Note that the target size of the rolled material of each billet after rolling is one type, and the target size is not changed during rolling from one billet.

[0003] As for the rolling order of billets, necessary billets are selected in view of the casting schedule of the continuous caster, that is, the HCR material supply plan, the current CCR stock status, and the delivery date of each material.
Determined by considering the distribution of steel slabs to the continuous heating furnace so as to satisfy the rolling restrictions such as the size change restriction and the strength difference restriction between the selected slabs and reduce the input fuel (fuel unit consumption). Is done. Such a rolling sequence has conventionally been created based on the experience of an operator, and thus requires a long time. In the case of immediate preparation, it is customary that the rolling order is determined in consideration of only the rolling constraints.

[0004] The order of rolling the billets is, for example, in a so-called coffin shape, in consideration of uneven wear on the surface of the work roll, etc., and the rolling width is changed from a wide plate to a narrow plate for each roll change unit. The plate is set to change in size.At this time, it must be within the range of the size change amount that allows continuous rolling without trouble between each billet, and the size change amount constraint between each billet is Imposed. If the size difference between the billet currently being rolled in the rolling process and the billet to be rolled next exceeds the allowable range, the error in setting the gap (roll gap) between the rolls of each rolling mill increases, Rolled plate thickness,
Variations in plate width increase, causing trouble.

[0005] When the rolling order is created, predetermined CCRs are piled up in the storage yard according to the rolling order. The piled slabs are sequentially supplied to the charging side table of the continuous heating furnace before and after the continuously cast HCR in order from the top in the rolling order, and the HCR and CCR on the charging side table are It is charged while being distributed to a plurality of continuous heating furnaces, heated to a target temperature, continuously extracted, and supplied to a rolling process.

[0006]

As described above, H
When CR and CCR coexist, it is not easy to determine the rolling order of the slab so that the fuel input to the continuous heating furnace is small and the rolling constraints are satisfied, and it takes a long time.

In addition, if the casting order changes from the planned stage due to a shift in the schedule prediction in the upstream process of the continuous casting process, a trouble in the upstream downstream process, or the like, it is necessary to create the rolling order again. However, a complicated operation of reloading the piles of steel slabs according to the rolling order before the change in accordance with the rolling order after the change is required, and the productivity is inevitably reduced. For this reason, it is difficult to flexibly change the rolling order according to the operation situation. Even if the casting schedule has been changed, if rolling is performed according to the rolling order before the change, the size change and strength (steel type) change during rolling may increase, and the frequency of troubles during threading increases. Or the rolling order may not be optimal in terms of the input fuel.

Japanese Patent Laid-Open Publication No. Hei 7-236555 discloses a rough planning step of arranging unitized blocks having an approximate attribute range for a material specific element including a casting metal type and a rolling size for HCR. Each block is divided into more approximate cell units, and the system is divided into detailed planning stages that optimize evaluation items using dynamic programming.
A planning method for creating a casting-rolling operation procedure in a short time is shown. In this method, the casting order in the continuous caster is HC
The order of rolling is R.

[0009] By using the above method, the optimum HC
An R casting schedule can be created, but in actual rolling, it is necessary to create a rolling sequence by combining the HCR and the stock CCR, and the combined CCR is used by the operator as an interrupt process during the HCR casting plan. Incorporate. At this time, it is necessary to consider rolling restrictions and distribution of the continuous heating furnace for each steel slab, not for each cell, so that it takes a long time to determine the rolling order.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a method of storing stock steel slabs capable of promptly supplying CCR to a continuous heating furnace according to a changed rolling order when the rolling order is changed. A method of creating a rolling order that can rapidly determine the rolling order and a method of heating a slab that can flexibly cope with a change in the rolling order while reducing the input fuel for a slab mixed with CCR. provide.

[0011]

According to the first aspect of the present invention, there is provided an inventory billet storage method for grouping inventory billets stored in a storage yard and storing them in groups.
The stock steel slabs are grouped so that any two steel slabs in the group have a change in size and a change in strength of a rolled plate in which they are rolled are within a range where continuous rolling is possible.

According to the present invention, even if a specific stock slab is required due to a change in the rolling order, the change in size and the change in strength of the rolled plate are within the range in which continuous rolling is possible (within this range, the rolling constraint is limited). Of course, the stock billets are arranged in groups and stored in storage yards so that required stock billets can be replaced with any stock billets in the group to which the stock billets belong. And can be supplied to a continuous heating furnace. For this reason, even if the rolling order of the billet is changed, it is not necessary to reload the stock billet based on the changed rolling order unlike the related art. The rolling order in the present invention is not limited to the rolling order created by the invention described in claim 2 described later. In addition, as for the method of storing stock billets in each group, it is better to store them in piles because the storage space is small, and when removing stock billets from that group, they can be taken out in order from the top of the pile. I just need.

Further, according to the present invention, there is provided a direct-feeding steel slab directly charged into a continuous heating furnace without being stored in a storage yard after casting by a continuous casting machine, and a stock steel stored in a storage yard. The pieces are divided into groups such that the size change and the strength change of the rolled plate obtained by rolling any two steel slabs in the group are within the range in which continuous rolling can be performed. The rolling order of the direct-feeding steel slabs is determined so as to be continuous, and between different groups, so that any direct-feeding slab belonging to each group satisfies the rolling constraint. When the slabs are charged into the continuous heating furnace for direct billet, the timing for extracting all the direct billets belonging to the group and the time for extracting stock bills to be charged into the continuous heating furnace for stock billet are different. same A steel strip rolled in order to create a method for determining a rolling sequence of inventories steel pieces belonging to the group and the same group so that in the period.

According to the present invention, both the stock slab and the direct-feed slab do not need to consider the rolling constraints in the same group one by one, but only the rolling constraints when transferring to another group. The rolling order can be quickly determined for each group. Further, the rolling order of the direct-feed slab can be determined on a group basis regardless of the presence of the stock slab, and the rolling order of the stock slab can be determined for each group according to the rolling order of the direct-feed slab. Since it is possible, the rolling order of the steel slab in which the stock slab and the direct slab are mixed can be quickly created. For this reason, even if the casting order is changed, the changed rolling order can be quickly created.
In addition, since high-temperature direct-feeding slabs and stock slabs at room temperature are heated to the target temperature by dedicated continuous heating furnaces, both direct-feeding slabs and stock slabs are mixed in one continuous heating furnace. It is possible to prevent wasteful burning of the directly fed steel slab which occurs when heating is performed, improve the heating efficiency, and reduce the input fuel. The present invention is particularly effective when the ratio of direct-feed slabs to all slabs to be rolled accounts for 40 to 60%.

According to a third aspect of the present invention, in accordance with the second aspect of the present invention, a stock slab is stored in a storage yard for each group in accordance with the grouping of the second aspect. In addition to charging the direct-feeding slab into the continuous heating furnace for direct-feeding slabs according to the order, the necessary stock slabs stored in the storage yard according to the rolling order of the stock slabs according to claim 2 are stored in the storage yard. This is a method of heating a billet taken out of an arbitrary billet in a group to which the group belongs and charged into a continuous heating furnace for billet.

According to the present invention, stock billets belonging to a certain group required according to the rolling order are stored in the storage yard for each group, and are optionally stored in the same group as the group to which the stock billets belong. Therefore, the stock slabs can be quickly charged into the continuous heating furnace for stock slabs without stacking the stock slabs in advance according to the rolling order. Also, even if the rolling order of the direct-feed slab changes, the necessary stock slab can be quickly charged.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall layout around a continuous heating furnace, showing a first continuous heating furnace 1 for heating a direct-feed slab.
A second continuous heating furnace 2 for heating stock slabs is juxtaposed, a charging side table 4 is provided on the upstream side, and an extraction side table 5 is provided on the downstream side. The charging side table 4 is supplied with a direct-feed billet (HCR) 10 from a continuous casting facility and a stock slab (CCR) 11 from a storage yard.
0 and CCR11 are charged into a first continuous heating furnace 1 and a second continuous heating furnace 2, respectively, heated to a target temperature, and then carried out by an unloading device attached to the first and second continuous heating furnaces 1 and 2. It is carried out to the extraction side table 5.

A rolling command plan creation computer 6 for designating a steel slab to be manufactured is provided. The rolling command plan creation computer 6 includes a scheduling computer 7 for determining the rolling order of the slab and a crane control device 8. It is attached. The scheduling computer 7 stores a rolling order determining program, and the rolling order determining program determines a rolling order of the HCR and the CCR designated as a manufacturing object.

In the storage yard, as shown in FIG. 2, for example, as shown in FIG. 2, the CCR is a range in which a change in the rolled plate size when any two steel pieces in a group are rolled can be continuously rolled for each rolled plate strength level. A11 to 14, A21 to 24, A according to the target plate thickness T and the target plate width W of the rolled plate so as to be within.
They are grouped into groups such as 31 to 34 and piled up.
“A” of the group number indicates an intensity level.
If the steel slabs having the largest size difference among the steel slabs in the group are within the continuous rolling range, all the steel slabs having the size difference therebetween belong to the same group.

FIG. 3 is a main flowchart showing the contents of the rolling order determination program. First, the casting order of the HCR to be cast specified by the rolling command plan creation computer 6 is determined (step S1). The casting order is determined so that HCRs belonging to the same group are continuously cast. When casting different groups of HCRs for one charge of the converter, the casting order is usually determined so as to shift from the wide material group to the narrow material group due to the restriction on the size change of the continuous casting mold. .

Next, HC charged into the first continuous heating furnace 1
Determine the rolling order of R. The rolling order of the HCRs is created so that the HCRs of the same group are continuous, and that between different groups, any HCRs belonging to each group satisfy the rolling constraint.

More specifically, the casting order is provisionally determined as a rolling order (step S2), and with respect to all the groups arranged in the rolling order, any HCRs belonging to the preceding and succeeding groups satisfy the rolling constraint. The rolling order is changed for each group (step S3). When judging whether or not any of the slabs belonging to the two groups to be compared satisfies the rolling constraint, in practice, the slabs having the largest size difference among the slabs belonging to each group are determined by the rolling constraint. It suffices to judge whether or not the above is satisfied. With regard to the determination of the rolling constraint, it is first determined from the material strength difference constraint whether or not the ranking is allowed, and if so, it is further determined whether or not the size change amount constraint can be satisfied. Since the HCRs belonging to the same group satisfy the rolling constraints, the rolling order of the HCRs is arbitrary. For example, the casting order may be set as the rolling order.

Next, the HCR determined as described above
The rolling order of CCR is determined based on the rolling order of. That is, when the HCR belonging to a certain group is sequentially charged into the first continuous heating furnace 1 for each group arranged in the rolling order of the HCR, the extraction time of all the HCRs belonging to the group and the second The rolling order of the CCR belonging to the same group as the above group is determined so that the extraction time of the CCR extracted from the continuous heating furnace 2 is the same as the extraction time (step S4).

For example, if the HCR belonging to a certain group is m
When there are books and there are n CCRs belonging to the same group,
In the case where m HCRs are heated to the target temperature over the T time and extracted from the first continuous heating furnace 1, the n CCRs are set to the target temperature at the T time so as to be at the same time as the HCR extraction time. And the rolling order is determined so as to extract from the second continuous heating furnace 2. As in the present embodiment, when the number of tables 4 to be charged into the continuous heating furnaces 1 and 2 is one, m HCs
When supplying R, the rolling order may be determined so that CCR is supplied at a rate of n / m per HCR. On the other hand, the nth CCR is heated and extracted to the target temperature in the T time. What is necessary is just to control the amount of heat supplied to the two continuous heating furnace 2. Since the rolling order of the CCRs belonging to the same group may be arbitrary, when supplying the CCRs from the storage yard to the charging side table 4, the CCRs stacked in the storage yard for each group are arranged in order from the top one. What is necessary is just to take out and supply.

FIG. 4 shows an example of the rolling order (also the order of charging the continuous heating furnace) from roll change to roll change determined as described above. 2 shows the group name described in FIG. In this example, A22 → A
33 →... → A31 is charged into the continuous heating furnace, and for each group, HCR and CCR are extracted from the first continuous heating furnace 1 and the second continuous heating furnace 2 at the same time and rolled. Provided. Although HCR and CCR are mixed in each group, the rolling order between HCRs and between CCRs is arbitrary within the same group, as described above. The rolling order of the HCR and the CCR in a certain group is such that when the HCR is charged into the first continuous heating furnace 1, the extraction time of all the HCRs belonging to the group and the CCR of the CCR belonging to the same group as the group are determined. 2 continuous heating furnace 2
The rolling order of the CCR is determined so that the extraction time from CCR is the same as the extraction time.

As described above, the rolling order of the HCR and the CCR is determined, heated to the target temperature in the first and second continuous heating furnaces 1 and 2, extracted, and sequentially supplied to the rolling process. According to the method of the present invention, even if the casting order is changed for some reason, the storage yard has a pile of CCRs for each group, so that the storage order is adjusted to the rolling order of the HCR determined from the changed casting order. , The required CCR can be taken from any of the same groups to which it belongs and fed to a continuous furnace.

The HCRs are loaded into the first continuous heating furnace 1 in groups, that is, HCRs belonging to the same group are continuously charged into the first continuous heating furnace 1 according to the rolling order. If it is necessary to change the rolling order between the groups at the time of insertion, it is necessary to temporarily wait for a certain group having the HCR after casting. However, the HCR of the waiting group becomes room temperature like the CCR due to the standby. It will not be cooled down.

In the above embodiment, the HCR casting order is also determined by the rolling order determination program of the scheduling computer 7, but the casting order may be determined by another program or computer. Further, the continuous heating furnace for HCR and CCR heating is not limited to one furnace as in the embodiment, but may be a plurality of furnaces according to the processing capacity of the rolling line.

[0029]

As described above, according to the stock slab storage method according to the first aspect, the necessary CCR is determined according to the rolling order.
Take it out of anything in the group to which it belongs,
It can be quickly supplied to the continuous heating furnace, and can flexibly cope with a change in the rolling order.

[0030] According to the billet rolling sequence making method of the second aspect, the rolling sequence of the billet in which the stock billet and the direct billet are mixed is promptly made in consideration of the reduction of the input fuel. And the rolling order can be quickly changed according to the change in the casting order.

According to the billet heating method described in claim 3, according to the rolling sequence created by the invention of claim 2, necessary stock billets can be stocked without pile up stock billets in advance. It can be quickly charged into a continuous heating furnace for billets. Also, even if the rolling order of the direct-feed slab changes, the necessary stock slab can be quickly charged.

[Brief description of the drawings]

FIG. 1 is an overall arrangement diagram of an apparatus configuration around a continuous heating furnace according to an embodiment.

FIG. 2 is an explanatory diagram of group division divided into ranges in which continuous rolling is possible based on a target sheet thickness and a target sheet width of a rolled material.

FIG. 3 is a main flowchart of a rolling order determination program.

FIG. 4 is a conceptual diagram of a rolling order displayed in a group unit in the embodiment.

[Explanation of symbols]

 Reference Signs List 1 1st continuous heating furnace (continuous heating furnace for direct billet) 2 second continuous heating furnace (continuous heating furnace for stock billet) 7 Scheduling computer 10 direct billet 11 stock billet

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C21D 9/00 101 C21D 11/00 11/00 B21B 37/00 BBH G06F 17/60 G06F 15/21 R

Claims (3)

[Claims] 1. A stock slab storage method for grouping stock slabs stored in a storage yard and storing the slabs in groups, wherein any two slabs in the group are rolled. An inventory slab storage method for grouping inventory slabs so that a change in size and a change in strength of a rolled plate are within a range in which continuous rolling is possible. 2. The method according to claim 1, wherein the continuous casting machine casts the directly fed steel bills directly charged into the continuous heating furnace without being stored in the storage yard after the casting and the stock steel bills stored in the storage yard. The steel slabs are grouped so that the size change and strength change of the rolled plate in which they are rolled are within the range that can be continuously rolled, so that the direct-feed slabs belonging to the same group are continuous and between different groups. Then, the rolling order of the direct-feeding slabs is determined for each group so that any direct-feeding slab belonging to each group satisfies the rolling constraint, and the direct-feeding slabs belonging to a group are continuously heated for the direct-feeding slabs according to the rolling order. When charging the furnace, the extraction time of all direct-feed billets belonging to the group and the extraction time of the stock bill to be charged into the continuous heating furnace for the stock billet are the same as those of the aforementioned group so that the extraction time is the same. Steel strip rolling order to create a method for determining the rolling order of the stock steel pieces that belong to a group. 3. A stocked billet is stored in a storage yard for each group according to the grouping according to claim 2, and the billet is directly transferred according to the rolling order of the billet according to claim 2. A stocked slab in the group to which the stocked slab belonging to the stock slab that is charged in the continuous heating furnace and stored in the storage yard according to the rolling order of the stocked slab according to claim 2. A method of heating billets by taking them out of the furnace and charging them into a continuous heating furnace for stock billets.