JP2002210548A - Method and apparatus for gas-cutting continuously cast slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cutting cast slabs having different lengths in continuous casting equipment, and an apparatus for realizing the method. SOLUTION: The method is for gas-cutting the continuously cast slab in the width direction by using a gas-cutting apparatus 1 which is provided with a plurality of sets of gas cutting torches 5, 6 having different cutting performances, mounted with a torch traversing apparatus 2 shiftable in the width direction of the cast slab M during continuous casting and travels in synchronism with the shift of the cast slab. The method comprises arithmetically processing a cutting length of the cast slab, a casting condition and an output from a position detector 13, then selecting the torch from the plurality of sets of gas-cutting torches according to the length of the cast slab to be cut, and cutting the cast slab.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting a continuously cast slab in the width direction in a cutting zone of a continuous casting apparatus and an apparatus for carrying out the method, and more particularly to a cutting length of the slab. The present invention relates to a method for performing cutting suitable for a required purpose such as quality of a cut surface, a cutting margin, and an apparatus for performing the method.

[0002]

2. Description of the Related Art Continuously cast slabs are formed into various shapes through rolling and other processes to produce products. Depending on the size of the product, slabs of various lengths are required and cut in the cutting zone of the continuous casting machine. As the slab cutting device, a trolley type gas cutting device (hereinafter, referred to as "gas cutting device") mounted with a gas cutting machine that reciprocates in the width direction of the slab and reciprocates in the drawing direction of the slab. Or, a bogie type shear cutting device (hereinafter, referred to as a "shear cutting device") which carries a shear cutting machine and reciprocates in the direction of drawing a slab is used.

The shear cutting device can cut short cast slabs because the cutting time is short, but the equipment is large, the equipment cost is high, and the maintenance cost for maintaining the accuracy of each part is high. Therefore, most continuous casting facilities are equipped with a gas cutting device. However, the gas cutting device has a longer cutting time than the shear cutting device, and the shortest cutting length of the slab is limited.

[0004] Recently, the needs of steel users tend to be small lots and many kinds, and the demand for short cast slabs is increasing. However, it is difficult to cut a slab short in a continuous casting facility that can perform high-speed casting and has a gas cutting device.

In order to shorten the cutting length of the slab when using the gas cutting device, the cutting is started from the time when the cutting is started while running in synchronization with the slab, and then the position where the cutting is started. It is sufficient to shorten the time required to return to (cutting cycle time).

FIG. 1 is a diagram for explaining a cutting cycle time when cutting a continuous cast slab by a gas cutting device.

[0007] This figure two cutting performance equal gas cutting torch (5-1, 5-2) is at the slicing end from the cutting start position P ₁ and Q ₁ on both sides of the slab width direction P ₂ and Q Gas cutting torch while traveling to position ₂ (hereinafter simply "torch"
FIG. 7 is a schematic diagram for explaining a movement route of the present invention. The torch (5-1, 5-2) traverses toward the center in the width direction of the slab while moving in synchronization with the removal of the slab M by the traveling carriage. Cutting is initiated at the position of the P ₁ and Q _1, in this figure is depicted as being initiated from the position of P ₂ and Q _2.

The torch (5-1) is located at the position P₂Start disconnecting from
Then P₂To P₃Until the end of the slab, make a notch
Start period, and the cutting speed is relatively low. Position P₃Or
R P₄Up to this point, cutting is performed at a predetermined cutting speed. Position P
₄When cutting is completed, the torch is returned in the width direction of the slab.
At the same time as the original position P ₁
Is returned to.

The other torch (5-2) is the same as the torch (5-
Opposite the 1) starts cutting from position to Q ₁ opposite to the slab width direction, it is returned to the position for Q ₁ in substantially the same operation as torch (5-1). Incidentally, the cutting from the position P ₄ to Q ₄ are carried out either in the torch.

The cutting cycle time is, as shown in FIG. 1, the time from when the cutting torch (5-1, 5-2) starts to return to its original position. If the cutting cycle time T (min) becomes longer, it is necessary to increase the length L (m) of the slab to be cut next. This cutting length L (m) is the slab drawing speed.
Vc (m / min), the cutting cycle time T (min) and the allowance time Ta (min) are calculated as follows. When the margin time Ta is zero, the shortest cutting length of the slab can be obtained.

L = Vc (T + Ta) To reduce the cutting cycle time, the time required for cutting
(Position P in FIG. 1₃To P ₄Cutting time up to
That is, the cutting performance of the torch may be improved.

As the gas cutting torch, there is an integrated torch in which a preheating crater and a cutting crater are concentric double tubes, or an independent torch in which these are joined in parallel. At the preheating crater,
A preheating flame is injected to heat the starting point of the slab to the ignition temperature. At the cutting crater, oxygen is blown at a relatively high pressure (around 1 megapascal) to burn the steel and cut the slab. The gas cutting torch includes a high-speed cutting torch, a best yield cutting torch, and a best quality cutting torch.

The high-speed cutting torch is a torch having a large crater diameter, which cuts at a high speed by supplying a large amount of oxygen at a stable pressure. If this is used, the cutting cycle time is shortened, and the length of the cast piece to be cut next can be shortened. However, the amount of steel burned and removed from the slab (also referred to as “cut width” or “cut allowance”) increases, and the yield of the slab decreases. In addition, there is a large loss of oxygen combustion during cutting, and the amount of cutting slag increases, resulting in an increase in the cost of producing slabs.

The best yielding cutting torch is a torch having a small crater diameter and cutting with a small amount of oxygen at a stable pressure. When this is used, the amount of steel burned and removed from the slab is reduced, and the cutting yield of the slab is improved. In addition, since the amount of cutting residue is reduced, the quality of the steel material obtained in a lower process such as rolling is improved. However, the cutting cycle time becomes longer, and the length of the slab to be cut next becomes longer. The best quality cutting torch is almost equal to this.

As described above, since the size of the crater diameter differs between the high-speed cutting torch and the best yield cutting torch, it is difficult to perform both cutting methods with the same torch.

Generally, a gas cutting device of a continuous casting facility is equipped with one type of torch according to the specifications of the continuous casting facility. When a high-speed cutting torch is mounted on this, the cutting yield of the slab decreases. In addition, when the best yielding torch is mounted, the cut length of the slab becomes long, and when a short slab is required, the slab is cut again at another place.

As described above, as a method of cutting a slab into short lengths by using a high-speed continuous casting facility, two gas cutting devices are continuously arranged in series (skewer type) on a slab drawing line, and the slab temperature is reduced. There is a method of determining the gas cutting speed from the chemical composition of the slab and cutting the slab sequentially from the gas cutting machine on the downstream side to shorten the shortest cutting length of the slab (JP-A-6-71396, reference).

[0018]

However, the above-mentioned method of continuously arranging the two gas cutting devices in series increases the equipment cost, increases the length of the transfer table of the casting equipment, and increases the existing continuous casting equipment. It is difficult to install.

An object of the present invention is to provide a method for cutting short cast slabs with a single gas cutting device that runs reversibly in the direction of drawing slabs, and an apparatus for realizing the method. is there.

[0020]

Means for Solving the Problems In order to achieve the above object, the present inventors have set a plurality of gas cutting torches (for example,
High-speed cutting torch and the best yielding cutting torch), and according to the cutting length of the continuous cast slab, steel type, casting speed,
The present invention was completed by selecting one of the plurality of gas cutting torches based on a quality control standard, a slab cutting yield, and the like, and setting an optimum cutting condition to perform cutting.

The gist of the present invention resides in a method for cutting a continuous cast slab shown below and a gas cutting device for a continuous cast slab shown below for carrying out the method (see FIG. 2).

A torch traversing device equipped with a plurality of gas cutting torches having different cutting performances and capable of moving in the width direction of the slab during continuous casting is mounted, and a gas cutting device running in synchronization with the movement of the slab is used. A method of cutting a slab in the width direction, the arithmetic processing of the cutting length of the slab, the casting conditions and the output from the position detector, the torch according to the length of the slab to be cut next, A gas cutting method for continuous cast slabs that selects and cuts from a plurality of gas cutting torches.

A gas cutting device 1 for cutting a slab in the width direction while running in synchronization with the movement of the slab M during continuous casting, comprising two traveling rails laid outside the slab in the width direction.
A traveling trolley 4 that travels on 8, 8 in parallel with the slab pull-out direction is provided, and the traveling trolley is provided with a cross beam 3 in which a reference rail 10 and a slave rail 11 are laid in the width direction of the slab. On those rails, a torch traversing device 2 that can move in the width direction of the slab is mounted, and the torch traversing device is equipped with a plurality of gas cutting torches 5, 6 having different cutting performances. Gas cutting equipment.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION A gas cutting method for a continuous cast slab according to the present invention uses a plurality of gas cutting torches having different cutting performances (for example, a high-speed cutting torch and a best yield cutting torch).
Equipped with a traversing device that can reciprocate in the width direction of the slab, using a gas cutting device consisting of a carriage that can reciprocate in the drawing direction of the slab, steel type, casting speed, This is a method in which one is selected from the plurality of gas cutting torches based on a quality control standard, a slab cutting yield, and the like, and cutting is performed by setting optimum cutting conditions.

FIGS. 2A and 2B are conceptual views showing an example of a gas cutting device for carrying out the slab cutting method of the present invention, wherein FIG. 2A is a front view as seen from the direction in which the slab is pulled out, and FIG. FIG. 4C is a side view, and FIG.

As shown in FIG. 2, the slab gas cutting apparatus 1 of the present invention comprises a traveling cart 4 for traveling in the direction in which the slab M is pulled out.
And is mounted on the traveling carriage 4 and travels in the width direction of the slab 2
It consists of two torch traversing devices 2,2. Hereinafter, in this specification, "running in the width direction of the slab" is simply referred to as "traversing" and "running in the direction of drawing the slab".
Is called "running".

The traveling carriage 4 has wheels 9, 9 traveling on two traveling rails 8, 8 laid in parallel with the slab pull-out direction with an interval wider than the slab width. Further, a cross beam 3 provided with a slave rail 11 in the width direction of the slab is provided.

The torch traversing device 2 comes in contact with a torch support rod 7 provided with a plurality of gas cutting torches having different cutting performances (high-speed cutting torch 5 and best yield cutting torch 6 in the figure) and the reference rail 10. A drive 12 for traversing the wheels and guide wheels and the device is provided.
The guide wheels are in contact with both side surfaces of the reference rail 10 and serve to stably traverse the torch traversing device.

The traveling rails 8, 8 are provided between reference numerals 15 and 16 (cutting zone), and a position detector 13 for detecting the position of the traveling vehicle is provided between the rail and the traveling vehicle. Reference numeral 14 denotes a length measuring device (measure roll) for measuring the length of the slab.

The gas cutting device of the present invention has a plurality of torches having different cutting performances on a single traveling vehicle as described above. The torch selection, cutting conditions, running conditions, and the like are obtained from the user information and the computing device, and cutting can be performed under the optimum cutting conditions. Here, the operating conditions include a slab size (thickness, width, length), a casting speed, a secondary cooling method, and the like, and the user information includes a sheet removal plan based on the slab size, a steel type, and the like.

Next, a method of cutting a slab using the above gas cutting device will be described.

FIG. 3 is a block diagram showing an arithmetic system used in the present invention.

Operation information such as casting speed, slab temperature, and secondary cooling method, and user information such as slab size, slab weight, board plan, steel type, etc. are input to the arithmetic unit, and oxygen pressure, oxygen flow rate, torch traverse. After calculating the speed, the traveling speed of the trolley, and the like, one cutting torch is selected, and is output to the gas cutting device to perform cutting. The cut slab is weighed,
The data is input to the arithmetic unit, compared with the slab weight in the user information, and provided to the next step.

FIGS. 4A and 4B are schematic diagrams for explaining the positional relationship between the cutting torch and the cut slab. FIG. 4A shows a case where a high-speed cutting torch is used, and FIG. (C) The best quality cutting torch is used. This figure shows the cut slab and the cutting start position of the slab, the black arrow indicates the position of the torch at the end of cutting, and the white arrow indicates the position of the torch at the time of starting this cutting. is there. The time between the black arrow and the white arrow is the cycle time T (min) required for cutting, and varies depending on the performance of the torch used.

The length of the slab to be cut (L ₁ , L ₂ , Lmin)
The cutting order (L ₁ , Lmin, L ₂ ) is determined as user information in the planner plan, and is input to the computing unit in advance.

In the case of cutting the slab of length L _1, since then the length of the slab to be cut is Lmin, high speed cutting torch 5 by the computing system shown in FIG. 3 is selected, Fig. 4 (a as shown in), high-speed cutting is carried out from the cutting start position S _1, E ₅
The cutting ends at the position. Cutting start position S ₁ from measuring machine (major role) 14 as the distance D _S1 to the torch 5, to a position where the previous cut ended from the position of the length measuring machine 14 (the right end portion of the cast piece shown in phantom) Distance L ₀ and length measuring device 14
The distance D ₁ of the the to the position detector 13 measures the position detector 13 of the length measuring machine 14 and the traveling vehicle, determined by the following equation (1). _{D S1 = L 0 -L 1 =} D 1 + d 5 ····· (1) where, _{d 5} is the distance from the position detector 13 to the torch 5.

Next, when cutting a slab of length Lmin,
Since then the length of the slab to be cut is L _2, yield the best cutting torch 6 is selected by the computing system, as shown in FIG. 4 (b), a relatively low speed in cutting from the cutting start position S ₂ It is performed and cutting is completed at the position of E _6. Cutting start position S ₂ at this time, the distance from the length measuring machine 14 as the distance D _S2 to the torch 5, the L ₀ of (1) from the cutting end position E ₅ of L ₁ slab to length measuring machine 14 , the distance from the length measuring machine 14 to the position detector 13 as D _2, determined by the equation (2). _{D S2 = L 0 -Lmin = D} 2 + d 6 ····· (2) where, _{d 6} is the distance from the position detector 13 to the torch 6.

[0038] Moreover, when cutting the slab of length L _2, if then the length of the slab to be cut is a cast piece to emphasize quality L _2, quality best cutting torch by calculating the system
n is selected, as shown in FIG. 4 (c), is performed relatively slow cutting from the cutting start position S _3, the cutting is completed at the position of the En. Cutting start position S ₃ at this time, the distance from the length measuring machine 14 as the distance D _S3 to torch n, the L ₀ of (1) from the cutting end position E ₆ of Lmin slab to length measuring machine 14, the distance from the length measuring machine 14 to the position detector 13 as D _3, determined by the equation (3). _{D S3 = L 0 -L 2 =} D + dn ····· (3) where, dn is the distance from the position detector 13 to the torch n.

Since the slab gas cutting apparatus of the present invention is equipped with a plurality of cutting torches having different performances, for example, the current cutting torch is selected according to the length of the slab to be cut next. Cutting can be performed under optimal conditions.

Next, a specific example of slab cutting will be described.

A gas cutting apparatus according to the present invention as shown in FIG. 2 equipped with a high-speed cutting torch and a best yield cutting torch was arranged in a vertical bending type continuous casting equipment line. The mold of this continuous casting facility can change the thickness of a slab to a thick plate or a book plate in a short time. First, the following conditions are input to the arithmetic unit of the slab cutting device of the present invention.

The conditions for selecting the cutting with the best yield cutting torch are slabs for thin plates, the slab thickness (t) is 250 mm to 270 mm, and the casting speed (Vc) is 1.4 m / min.
2.1 m / min, the slab cutting length (L) is 4.5 m to 10.5 m.

The conditions for selecting cutting by the high-speed cutting torch are (1) a slab for a thick plate, (2) a slab thickness (t) of 235 mm to 300 mm, and (3) a casting speed ( Vc) is 1.0m / min
1.8 m / min, (4) The slab cutting length (L) is 3.5 m to 10.5 m.

After cutting a slab for a thin plate having a slab thickness of 270 mm with a cutting length of 8.0 m, a plan for cutting a slab having a length of 4.5 m was input to a computing unit to perform a test.

When continuously cutting a slab having a cutting length of 8.0 m, the cutting cycle time can be made sufficiently long, so that the best yielding torch can be used. However, in order to cut a slab with a cutting length of 4.5 m on the way or at the end, 4.5 m
It is necessary to shorten the cutting cycle time when cutting the slab (8.0 m) before the slab.

Since the above-mentioned plan is input to the arithmetic unit, the cutting torch shown in FIG. 4 (a) is used as a cutting torch for cutting a 8.0 m cast piece before cutting a 4.5 m cut piece. As shown in (1), a high-speed cutting torch is selected, the cutting position is determined by the above-described equation (1), and high-speed cutting is performed.

The cutting of the 4.5 m cast slab can be predicted to be possible in the cutting zone even at the cutting cycle time of the best yield cutting torch, so the cutting shown in FIG. Is performed. Here, the cutting of the 4.5 m slab
When cutting one sheet, the first to fourth sheets are cut in the pattern (high-speed cutting) shown in FIG. 4A, and when cutting between the fifth sheet and the sixth sheet, FIG. The cutting is performed in the pattern shown in (c).

[0048]

According to the slab cutting device of the present invention, a plurality of cutting torches having different performances are arranged in one traversing device.
An optimum cutting torch can be selected according to a board plan, casting conditions, and the like, which are production information input to the arithmetic unit, and a slab having the target length can be cut. As a result, the yield and cutting efficiency of the slab can be improved, and the slab having the length required for the lower process can be supplied with good timing.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a cutting cycle time when cutting a continuous cast slab by a gas cutting device.

FIG. 2 is a conceptual diagram showing an example of a gas cutting device for performing a slab cutting method of the present invention, wherein (a) is a front view as seen from a direction in which the slab is pulled out, (b) is a side view, (c) is a plan view seen from above.

FIG. 3 is a conceptual diagram showing an example of a gas cutting device for carrying out the slab cutting method of the present invention, wherein (a) is a front view as seen from a direction in which the slab is pulled out, (b) is a side view, (c) is a plan view seen from above.

FIG. 4 is a schematic view for explaining a positional relationship between a cutting torch and a cut slab, where (a) shows a case where a high-speed cutting torch is used, and (b) shows a case where a yield best cutting torch is used. (c) The case where the best quality cutting torch is used.

[Explanation of symbols]

 1. Cutting device 2. 2. Torch traverse device Horizontal girder 4. Traveling trolley 5. 5. High-speed cutting torch 6. Best yield torch 7. Torch support rod Running rail 9. Running wheel 10． Reference rail 11． Slave rail 12. Drive unit 13. Position detector 14. Measuring instrument (measure roll)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B23K 7/10 B23K 7/10 R

Claims (2)

[Claims] A torch traversing device equipped with a plurality of gas cutting torches having different cutting performances and capable of moving in the width direction of a slab during continuous casting is mounted, and a gas cutting device that travels in synchronization with the movement of the slab is provided. A method of cutting a slab in the width direction by using a torch according to a length of a slab to be cut, a casting condition, and an output from a position detector, and then a length of the slab to be cut next. Is selected from the plurality of gas cutting torches, and cutting is performed using the torch. 2. A gas cutting device for cutting a slab in the width direction while running in synchronization with the movement of the slab during continuous casting,
A traveling carriage is provided that travels on two rails laid outside the slab in the width direction in parallel with the direction in which the slab is pulled out,
The traveling carriage is provided with a horizontal girder having a reference rail and a slave rail laid in the width direction of the slab, and a torch traversing device capable of moving in the width direction of the slab is mounted on those rails. A gas cutting apparatus for continuously cast slabs, wherein a plurality of gas cutting torches having different cutting performances are attached.