JP2000301308A - Method for deciding width of continuously cast slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deciding method of a slab width, with which the number of heats in a sequence casting as the unit of a kind of steel are maximized while adopting the castable max. width as large as possible and the cast efficiency of a continuous caster can be improved. SOLUTION: In the case of deciding the slab width corresponding to an individual order in the order group collected in the same kind of steel, the target value of each slab width is made to the castable max. width of each slab. When the width of the successively cast slab in the case of setting as the castable max. width, exceeds the max. width changing amount α during casting in the one heat in the continuous caster, the width of the successively cast slab is decided as in the range of the castable max. width and the castable min. width of the slab and the max. width changing amount α or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining a width of a slab corresponding to a steel product of an order when the slab is cast by a continuous casting machine. The present invention relates to a method for determining a slab width that enables continuous casting of a slab to be cast while adopting the maximum possible castable width.

[0002]

2. Description of the Related Art In the integrated iron and steel industry, various products are manufactured through the steps shown in FIG. In the blast furnace 11, iron ore is reduced with coke to produce pig iron having a substantially constant composition. In the converter 12, molten steel having a predetermined composition is manufactured by oxygen blowing of hot metal so as to obtain a steel type corresponding to a steel product of the order. The operation mode of the converter 12 is a batch system, and the molten steel produced for each refining is discharged to a ladle. Each refining is called heat, and the amount of molten steel in one heat depends on the capacity of the converter.

[0003] The produced molten steel is cast by a continuous casting machine 13 to be a slab which is a semi-finished product. Usually, the continuous caster 13 performs so-called continuous casting in which molten steel for several heats produced in the converter 12 is continuously cast in order to improve the productivity. However, it is preferable that the heats cast by continuous casting are of the same steel type. In continuous casting of different steel types, it is necessary to make the joints of the steel types scraps, which not only hinders productivity but also contradicts resource saving. Among the continuous casters 13, particularly in the slab continuous caster, in order to further increase the number of heats in one continuous casting from the viewpoint of improving productivity, the shorter side of the mold is moved during casting to change the mold width. A so-called width change is performed during casting, in which a slab having a width is also cast at a single casting chance. In the width change during casting, the maximum width change amount per width change is usually set to about 50 mm in consideration of the shape of the tapered slab manufactured at the time of width change.

[0004] The manufactured slab is sent to a thick plate process 14 or a hot rolling process 15 according to the order. What is rolled in the thick plate process 14 is shipped to customers as a so-called thick plate, and what is rolled in the hot rolling process 15 is a hot-rolled steel plate called a so-called hot coil, which is shipped as a product as it is, or After the cold rolling process 16 and the plating process 17 of the lower process, it is shipped as a cold rolled steel plate or a surface-treated steel plate.

[0005] In the thick plate process 14, since a thick product is manufactured by rolling in the length direction and the width direction of the slab, the restriction on the slab width corresponding to the product size is extremely loose. Hot rolling process 15
In recent years, a sizing press has been introduced in recent years, and a considerable amount of width rolling can be performed at the time of rolling, and the restriction on the slab width with respect to the product size has been loosened. For example, for a hot-rolled steel sheet having a width of a, from a-50 mm to a + 25
There is also a hot rolling step 15 that allows slabs up to 0 mm. In this case, the width change during casting of the continuous slab casting machine is 50.
If the pitch is mm, there are a plurality of slab widths that can be cast within the allowable width range. And in the steel mill where the hot rolling process 15 with the sizing press and the hot rolling process 15 without the sizing press are mixed,
Since orders having different allowable ranges of the slab width are mixed, it is particularly difficult to determine an appropriate slab width.

[0006] There are three attributes of the slab size accompanying the order: a nominal slab width, a maximum castable width, and a minimum castable width. Conventionally, operators aim to increase the casting efficiency of a continuous casting machine. A large amount of time was spent determining the slab width while looking at the list sorted in the slab nominal width so that the number of heats by one continuous casting increased and the width became as wide as possible within the allowable width range. .

[0007]

However, since the slab nominal width is set individually for each order, the overall connection is not taken into consideration, and the maximum castable width in the list arranged in the slab nominal width is the slab nominal width. It was difficult to grasp the whole picture of the order, because it could be reversed from the width. For this reason, the operator did not always determine the slab width so that casting was maximized one after another, and loss occurred.

[0008] The present invention has been made in view of the above circumstances,
The object is to provide a method for determining a slab width capable of improving the casting efficiency of a continuous casting machine by maximizing the number of heats of continuous casting in steel type units while adopting the maximum castable width as much as possible. It is.

[0009]

According to a first aspect of the present invention, there is provided a method for determining a width of a continuous cast slab, wherein the width of each slab corresponding to each individual order of an order group consolidated into the same steel type is determined. The target value is set to the maximum castable width of each slab. When the maximum castable width is set, the width of the slab to be continuously cast is set to the maximum width change amount α in one continuous casting machine width change during continuous casting. When it exceeds, the width of the slab to be continuously cast is determined to be within the range of the maximum castable width and the minimum castable width of the slab and not more than the maximum width change amount α.

The method for determining the width of a continuous cast slab according to a second aspect of the present invention is a method of determining the width of a slab corresponding to each individual order of a group of orders consolidated into the same steel type in the order of the largest castable width and the same maximum castable width. Within the range, the castable minimum width is classified in ascending order, and first, the maximum castable width and the minimum castable minimum width of the slab are determined as the maximum castable width of the slab, the width A. The difference between the width A of the slab and the maximum castable width of the next slab in the slab order is the maximum width change amount α of the width change during one casting of the continuous casting machine.
In the following cases, the width of the adjacent slab is defined as the maximum castable width of the slab, and the difference between the width A of the slab and the maximum castable width of the adjacent slab in the slab order is the maximum width change amount. If exceeds α, the maximum slab that can be cast in the slab order, including the next slab, goes back to a wider slab,
Within the range of the maximum castable width and the minimum castable width, a slab in which the slab width can be set to a width wider than the width A by the maximum width change amount α is found, and the width of the slab is set to the width A by the maximum width. The width of the slab adjacent to the slab whose width has been determined in this manner is sequentially determined in accordance with the above description.

In a third aspect of the present invention, in the method for determining the width of a continuous cast slab, the maximum width change amount α is set to 50 mm in the first or second aspect.

In the present invention, while keeping the width of each slab within the range of the maximum castable width and the minimum castable width of each slab, the width of the slab to be continuously cast is reduced by one of the continuous casting machines.
Since the maximum width change amount of the width change during casting is less than or equal to α, the continuous casting machine can perform the width change during casting while maximizing the continuous casting of each steel type unit. improves. Furthermore, since the maximum castable width of the slab is adopted as much as possible for the slab width, the amount of casting per unit time can be increased, and the casting efficiency of the continuous casting machine is further improved.

Further, the maximum width change amount α of width change during one casting operation.
Is set to 50 mm, so that the tapered slab manufactured at the time of width change during casting has a difference in width between the leading end side and the trailing end side of casting of 50 mm or less. It can be easily rolled into a hot coil having a uniform width with the rear end.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an example of transfer of order information related to the slab width determining method according to the present invention. First, referring to FIG. 1, transfer of order information related to slab width determination will be described.

The order receiving section 1 provided at the head office or the like receives an order for a thin steel sheet product from a customer. The order information at this stage includes contents such as product specifications, product width, total weight, and delivery date. Such order information is transmitted to each steelworks regularly, for example, once a week.

The product design department 2 of each steelworks performs quality design and production method design for orders from each customer. At this stage, information on the steel type and the slab nominal width, the maximum castable width, and the minimum castable width of the slab corresponding to the ordered product are given. The nominal slab width is obtained by adding the yield loss after the hot rolling process to the product width, and the nominal product width and the nominal slab width are generally substantially the same. The maximum castable width and the minimum castable width are calculated from the capacity of a width rolling machine or a width pressing machine in a hot rolling mill where the slab is rolled. Recently, a width rolling mill (Ve
Most hot-rolling mills can adjust the slab width by arranging a rtical scale breaker (abbreviation: VSB) or a sizing press. Incidentally, the width rolling mill has a castable width range of 150 mm and the sizing press has a castable width range of 300 mm.

The order information to which the manufacturing data is given by the product design department 2 is compiled into steel types and transmitted to the production planning department 3. The production planning section 3 is a section that determines the type of steel to be manufactured, its amount, and its manufacturing time based on the order information, and is a section that finally determines the width of the slab corresponding to the order. FIG. 2 is a flowchart showing a slab width determining method according to the present invention performed by the production planning section 3. Hereinafter, referring to FIG.
The maximum width change amount α of the width change during casting is 50 mm 2
According to the present invention in a steel mill having a strand-type slab continuous casting machine and a width rolling mill installed in one hot rolling mill and two hot rolling mills installed with a sizing press in the other hot rolling mill. The slab width determination method will be described. still,
In FIG. 2, W (I) is the slab width of the register number I,
max (I) is the maximum castable width of the register number I. Here, the register number is a number for identifying a slab, and is a serial number assigned to each slab corresponding to an order.

The production planning section 3 is an order DB for storing order information to which manufacturing specifications are given by the product design section 2.
4, the knitting unit 5 connected to the order DB 4 reads all the order information of a certain steel type. FIG. 3 shows an example of the read order. FIG. 3 shows a list of all 39 slabs corresponding to the order in the order of the slab nominal width from the wider slab nominal width to the narrower slab nominal width. The maximum castable width and the minimum castable width of each slab are shown together. . As shown in FIG. 3, it can be confirmed that a wide range and a narrow range are available.

First, these slabs are sorted and sorted in ascending order of the maximum castable width and in descending order of the castable minimum width within the same range, ignoring the slab nominal width. FIG. 4 shows the rearranged data. FIG.
Does not show the slab designation width. If the difference in the maximum castable width of each of the rearranged adjacent slabs is less than or equal to the maximum width change amount α in one casting width change, and 50 mm or less in this example, the continuous casting machine performs width change during casting. Casting is possible, and the maximum castable width of each slab is determined as the width of each slab, and the width setting operation ends. However, in the example of FIG.
m and there is a 150
mm, and thus it is usually not possible to cast all slabs by casting at the maximum castable width.

Therefore, among the rearranged slabs, the slab having the smallest castable maximum width and the minimum castable width, in this example, the slab width of the register number 39 corresponding to the 39th slab out of a total of 39 slabs Is determined to be 1050 mm, which is the maximum castable width of the slab. Next, the width of the slab (register number 38 in the example of FIG. 4) and the adjacent slab (register number 38) whose width has been determined in this way are determined. At this time, whether the difference between the maximum castable width of the adjacent slab (register No. 38) and the width of the slab (register No. 39) already determined is equal to or less than the maximum width change amount α of one width change during casting. Determine the width in two ways.

In the example of FIG. 4, since the maximum castable width of the register number 38 is the same as the slab width of the register number 39, the slab width of the register number 38 can be determined to be 1050 mm. That is, between adjacent slabs, when the difference between the maximum castable width of the slab whose width is newly determined and the width of the slab whose width has already been determined is equal to or less than the maximum width change amount α of one width change during casting. Is
The width of the slab for which a new width is to be determined is defined as the maximum castable width of the slab. Similarly, the width of the register number 37 is determined based on the width of the register number 38, and the maximum castable width of the register number 37 is 1050.
mm, the slab width of the register number 37 can be determined to be 1050 mm.

On the other hand, the difference between the slab width of the register No. 37 and the maximum castable width of the register No. 36 is 150 mm, which exceeds the maximum width change amount α of one width change during casting. From the maximum width change amount α of the width change during casting, three times of width change during casting is necessary to perform continuous casting. In addition, in the example shown in FIG. 4, since it is a two-strand continuous casting machine, two slabs are required for each width change during one casting, and therefore, the slab width is changed from 1050 mm to 1200 mm by 50 m.
A total of six slabs are required to spread at m intervals. Therefore, it goes back to the slab six ahead, and it is examined whether all six slabs can be tolerated for the width change. In the example shown in FIG. 4, the register number 36 and the register number 35 are tentatively set to 1100 mm, the register number 34 and the register number 33 are set to 1150 mm, and the register number 32 and the register number 31 are set to 1200 mm. Since it is within the range of the maximum castable width and the minimum castable width, it can be directly determined as the slab width. Since the maximum casting width of the register numbers 27 to 30 is equal to the slab width of the register number 31, the register numbers 30 to 27 can be traced back as 1200 mm width.

The difference between the slab width of the register No. 27 and the maximum castable width of the register No. 26 is 250 mm. In order to perform continuous casting, it is necessary to change the width during casting five times, so that the slab width is 1200 mm. A total of 10 slabs are required to expand the slabs from 1 to 1450 mm at 50 mm intervals. In this case as well, the slab width is provisionally set in the same manner as above, but when the register numbers 26 and 25 are temporarily set to 1250 mm,
The register number 25 becomes smaller than the minimum castable width, and the width cannot be set. In FIG. 4, since the minimum castable width is arranged in the order of the widest castable minimum width within the range where the maximum castable width is the same, a width of 1250 mm cannot be set for the stack numbers 18 to 24 where the maximum castable width is 1450 mm. It is. Therefore, register number 1
Going back before 7, secure a slab that can be cast with a width of 1250 mm. In the example shown in FIG. 4, the register number 17 can be cast at 1250 mm, and the register number 17 is determined to have a width of 1250 mm.

The minimum castable width of the register number 25 is 1350 mm
Therefore, it is impossible to set a width of 1300 mm. Therefore, as when securing a slab with a width of 1250 mm,
Two slabs that can be cast with a width of 1300 mm before register number 16 are secured. In the example shown in FIG.
Can be cast at 1300 mm, the register numbers 15 and 16 are determined to be 1300 mm. Then, return to Register No. 25, register No. 25 and Register No. 24 are 1350 mm wide, Register No. 2
The register number 3 and the register number 22 have a width of 1400 mm, and the register number 21 has a maximum castable width of 1450 mm. And register number 18
It goes back up to 1450mm width.

The slab following the register number 18 is the register number 14,
Since the difference between the slab width of the register No. 18 and the maximum castable width of the register No. 14 is 50 mm, the register No. 14 can have a maximum castable width of 1500 mm. Then, it goes back to the register number 1 with a width of 1500 mm and outputs the determined width. FIG.
Indicates the width of the slab determined in this way with a triangle.
FIG. 5 is a diagram in which the slabs corresponding to the order are rearranged in order from the widest slab width based on the determined slab width. The determination of the slab width in the production planning section 3 is automatically performed by the knitting section 5, and need not be illustrated at all as shown in FIGS. Also, if there is no order of the appropriate size and if it is not possible to continue casting continuously even by changing the width during casting, give up joining continuously by casting and give the divided casting as the maximum castable width as much as possible. Determine the width so that

As described above, in the present invention, the number of slabs corresponding to the minimum number of strands in each width is ensured for the width change during casting.
Since the width is determined so that casting can be performed by one continuous casting as a whole, and the maximum width that can be cast is adopted as much as possible, the casting efficiency of the continuous casting machine can be improved.

In the above description, the exchange of order information is 3
Although the description is divided into two sections, the present invention is not limited to the above, and the number of intervening sections may be any number as long as the order information is transmitted according to the above.
In the above description, when the slabs corresponding to the order are classified in the order of the largest castable width and in the same range of the largest castable width, the largest castable minimum width and the smallest castable width are obtained. Has been described as the Nth slab among the N pieces, but the slab having the smallest castable maximum width and the smallest castable width is assumed to be 1
As the third, the second and subsequent ones may be sequentially determined according to the above description.

[0028]

According to the present invention, the width is determined so that the casting can be performed by one continuous casting as a whole, and the maximum width that can be cast is adopted as much as possible, so that the casting efficiency of the continuous casting machine is improved. And has an industrially beneficial effect.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of transfer of order information relating to a slab width determining method according to the present invention.

FIG. 2 is a flowchart illustrating a slab width determining method according to the present invention.

FIG. 3 is a diagram showing examples of read orders in the order of slab designation widths.

FIG. 4 is a diagram in which the orders shown in FIG. 3 are rearranged in the order of the largest castable width and in the range of the smallest castable width when the maximum castable width is within the same range.

FIG. 5 is a diagram in which the orders shown in FIG. 3 are rearranged in the order of the slab width determined according to the present invention.

FIG. 6 is a production process diagram of a steel product in the integrated steelmaking steel industry.

[Explanation of symbols]

 1 Order receiving department 2 Product design department 3 Production planning department 4 Order DB 5 Knitting department

Claims (3)

[Claims] When determining the width of a slab corresponding to each individual order of a group of orders consolidated into the same steel type, the target value of the width of each slab is set to the maximum castable width of each slab. When the width of the slab to be continuously cast exceeds the maximum width change amount α of the width change during one casting of the continuous casting machine when the setting is large, the width of the slab to be continuously cast can be cast. A method for determining the width of a continuous casting slab, wherein the width is determined within a range between a maximum width and a minimum castable width and not more than the maximum width change amount α. 2. A slab corresponding to each individual order of a group of orders consolidated into the same steel type is classified in ascending order of the maximum castable width and in order of increasing the minimum castable width when the maximum castable width is within the same range. First, the width of the slab having the smallest castable maximum width and the minimum castable width is determined as the width A which is the maximum castable width of the slab, and then the width A of the slab is determined.
And the difference between the maximum castable width of the adjacent slab in the slab order and the maximum width change amount α of the width change during one casting of the continuous casting machine is less than or equal to the slab width. When the difference between the width A of this slab and the maximum castable width of the adjacent slab in the slab order exceeds the maximum width change amount α, the width including the adjacent slab is included. The slab order is traced back to a slab having a wider maximum castable width, and the slab width is set to a width wider than the width A by the maximum width change amount α within the range of the maximum castable width and the minimum castable width. A slab that can be found, the width of the slab is set to a value obtained by adding the maximum width change amount α to the width A, and the width of the slab adjacent to the slab whose width has been determined in this way is sequentially determined in accordance with the above. Characteristic method for determining the width of a continuous cast slab. 3. The method for determining the width of a continuous cast slab according to claim 1, wherein the maximum width change amount α is 50 mm.