JPH10156502A - Method for cutting off cast slab having changed width part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the straight going ratio of a cast slab and the integrated yield by checking whether the scheduled position of cutting-off of the cast slab contains the range from the starting position to the completing position of width changed part of the cast slab or not, and pre-giving an indication to a cutting-off machine according to the cutting-off of the width changed part based on this result. SOLUTION: When the indication of cutting-off of the width changed part at the following time is outputted to a control part of the gas cutting-off machine at the time of completing the cutting-off work before cutting off the width changed part, data related to the normal Y changing or the reverse Y changing in the width changed part and the angle, is transmitted. In the case the width changed part is the normal Y changing, the command which is made to longer by e.g. about 30mm (K part) than the ordinary cutting-off speed range is pre-given to the cutting-off machine side, and then, this work is shifted to the cutting-off at high speed in the following stationary part after fully cutting off the edge part of the cast slab at the low temp. In the case the width changed part is the reverse Y changing, the cutting-off is started after pre-retreating the gas cutting-off carriage at a fixed distance. The position (7b in the figure) is the starting point of the cutting-off at the retreated position.

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, and more particularly to a method for efficiently cutting a slab having a variable width portion.

[0002]

2. Description of the Related Art Generally, in continuous casting of slabs,
The slab width may be changed during the casting of one charge, but in order to cope with this, continuous casting is performed using a mold width variable device in which the short side of the continuous casting mold has a variable structure. Has been adopted. In such a case, since the short side of the mold is moved while continuing the casting, the slab slab to be cast naturally has a tapered width variable portion. The taper angle of the slab variable width portion becomes gentler and the deformation amount becomes smaller as the width variable speed becomes slower, and the angle becomes larger and the deformation amount becomes larger as the width variable speed becomes higher. In recent years, many of the operations have tended to shift to high-speed variable width, and a variable width portion having a relatively large angle is often present.

[0003] In a normal continuous slab casting facility,
As schematically shown in FIG. 5, the slab 2 drawn from the mold 1 is cut to a fixed size by the gas cutter 3 while solidifying and moving in the horizontal conveying section. Cutting work by this gas cutting machine, the cutting machine standing by in a state of straddling the slab clamps the upper surface of the slab that is conveyed by the cutting command,
A pair of gas cutting craters are moved in the slab width direction and cut in synchronization with the movement of the slab. After the cutting is completed, the clamp is released and returns to the home position, and waits for the next cutting. In addition, the cutting machine detects the side surface by a detector separately from clamping the upper surface of the slab, and issues a cutting start command to the cutting crater based on the detection.

[0004] When casting a slab having a variable width portion, there are two cases of changing to a slab having a small width and changing to a slab having a large width. In, the case is defined as forward Y variable and the case is defined as reverse Y variable.

[0005]

In the case where the width variable portion is variable in the positive Y direction, as shown in FIG. 6 (a), when the end face detector 4 of the cutting machine 3 detects the end face of the slab 2 a fixed distance. Although the slab does not exist at the cutting crater 5 provided at a distant position, the cutting starts, and the cutting cannot be performed in the predetermined cutting pattern. In addition, in the case of the reverse Y variable, as shown in FIG. 6B, at the time of detecting the end face of the slab, the position of the cutting crater 5 is an intermediate position that has passed the cutting start position. Leftover occurs and cannot be cut. Such a situation is not a problem when the amount of deformation is small, but occurs in the case of high-speed variable width in which the amount of width deformation is large (in recent years, such casting methods are common).

Therefore, conventionally, as shown in FIG. 6, cutting is not performed in the range of the variable width portion, and in any of the normal Y variable and the reverse Y variable, a non-cutting range as shown by hatching occurs. (A distance x between the torch position and the end face detection position is actually added to this range.) When such a non-cuttable range occurs in the slab, as shown in FIG. 5, for example, when cutting slabs No. 1 to No. 5 are to be collected from the slab, N
If there is a variable width part between o.1 and No.2 slabs, cutting will be performed at the length of No.1 plus this variable width part when cutting, and the slab of this part Is a reserved slab that cannot be sent to the next process as it is, and the slab slab straightness ratio (the ratio of the cut slab of the planned dimensions that can be sent from the cast slab to the next process as it is) and consistent The yield was reduced.

[0007] The present invention has been made to solve such disadvantages of the prior art, and it is possible to cut a slab having a variable width portion in the range of the variable width portion. It is an object of the present invention to provide a method for cutting a slab that can improve the slab slab orthogonality and the consistent yield.

[0008]

The gist of the present invention to achieve the above object is as follows. (1) In a method of cutting a slab cast by a gas cutting machine synchronized with a slab movement in a cutting zone, a slab cast by a continuous casting facility provided with a mold width variable device,
If the scheduled cutting position falls within the range of the slab width variable portion, depending on the taper angle of the width variable portion, change the cutting speed section of the cutting crater, or change the cutting start position of the cutting crater in the slab width direction. A method for cutting a slab having a variable width portion, comprising adjusting and starting a cutting operation at the variable width portion. (2) If the slab end face detector of the cutting machine detects the width variable portion when the width variable portion is positive Y variable, the cutting speed section of the cutting crater is extended by a distance corresponding to the taper angle of the width variable portion. The method for cutting a slab according to the above (1), comprising starting cutting after the cutting. (3) When the slab end face detector of the cutting machine detects the width variable portion when the width variable portion is inverted Y variable, the cutting crater is directed outward in the slab width direction according to the taper angle of the width variable portion. The method for cutting a slab according to the above (1), comprising starting cutting after moving by a distance that has been moved.

In the present invention, it is checked whether or not the predetermined slab cutting position calculated and determined in advance is included in the range from the start position to the end position of the conveyed slab. When the width variable portion is included, the width variable portion determines the forward Y variable or the reverse Y variable, and as a result, an instruction corresponding to each width variable portion cutting is given to the cutting machine in advance, so that the actual Cut the variable width part.

[0010] The taper amount of the variable width portion is 9/885.
If it is less than (mm), it is possible to perform cutting at the variable width portion as it is even with a conventional gas cutting machine. Therefore, the present invention can be applied to the case where the taper amount is 10/885 (mm) or more. preferable. In this case, 885 mm is the distance between the main torch and the end face detection position (the distance between reference numerals 6 and 7 in FIG. 2A), and 9 mm is e or 7a in FIG.
7b.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a plan view of a slab having a variable width portion when the slab width is changed during casting (positive Y variable), and FIG. 1B is a slab width changed to a narrow width. FIG. 4 is a plan view of the cast slab in the case (variable reverse Y), and in any case, cutting can be performed within the range of the variable width portion in the present invention. That is, at the end of the cutting operation before cutting the variable width section, an instruction for cutting the next variable width section is output to the control section of the gas cutting machine. And data on the angle and the like are sent. FIG. 4 shows a flowchart of the cutting operation of the variable width section.

In the case where the width variable portion is variable in the positive Y direction, FIG.
As shown in (a), when the injection of the cutting crater is started by detecting the end face of the cutting machine, the idle running section e is started before the actual cutting starts.
Will occur. 6 (open circle) in the figure is the end face detection position, and 7
(Black circles) indicate the cutting positions. In addition, the cutting speed is usually reduced in consideration of the low-temperature slab edge portion. However, the cutting speed section is shortened by the idle running section e, and there is a possibility that the cutting pattern is disturbed. Therefore, in the present invention, when the positive Y is variable, the cutting speed section is lengthened to cope with the problem, that is, the cutting speed section is previously extended to the cutting machine side by, for example, about 30 mm longer than usual (part k in the drawing). ), The operation is to completely cut the low-temperature slab edge portion, and then shifts to the next high-speed cutting of the steady portion. In addition to the lengthening of the cutting speed section, the cutting may be started after adjusting the crater in the slab width direction only in the idle running section e.

When the width variable portion is reverse Y variable, as shown in FIG. 2B, when the cutting crater injection is started by the end face detection 6 of the cutting machine, the position 7a is already in the slab. And an uncut portion is generated. Therefore, in the present invention, when the reverse Y is variable, the cutting is started after the blow tube carriage is retracted a predetermined distance (to a position beyond the slab edge) in advance. 7b of FIG. 2 (b)
Is the cutting start point retracted.

A case where an actual slab is cut according to the present invention will be described with reference to FIG. (A) is a cut-scheduled portion based on predetermined cutting information, which is to be cut into five pieces in FIG. (B) Result of operation, No.1 and No.2
5 shows that the width variable portion W has been generated over the cast slab. (C) shows the case of cutting based on the present invention, and cutting can be performed at the position of the variable width portion W, so that cutting can be performed in accordance with the cutting schedule determined in (a). As is clear from comparison with FIG. 5 which is a conventional cutting method, in the present invention, it is possible to cut to a fixed size irrespective of the presence of the variable width portion. Only 5 and
The remaining four can be picked up as scheduled and sent to the next process, whereas the conventional ones are cut off the variable width part, so the No. 1 and No. 5 slabs are reserved . J in the figure is the seam generated during the next charge

[0015]

As described above, according to the cutting method of the present invention, even a cast piece having a variable width portion can be cut without any trouble at the variable width portion, and the cutting at the variable width portion can be performed. Compared to the conventional cutting method that has been avoided, it is possible to improve the slab orthogonality and the consistent yield.

[Brief description of the drawings]

FIG. 1 is a plan view of a slab having a variable width portion to be cut according to the present invention, wherein (a) shows an example of forward Y variable and (b) shows an example of reverse Y variable.

FIGS. 2A and 2B are explanatory diagrams showing a cutting method according to the present invention, wherein FIG. 2A shows an example of forward Y variable and FIG. 2B shows an example of reverse Y variable.

FIG. 3 is an explanatory diagram showing a cutting schedule, actual results, and a cutting procedure when cutting a slab by the cutting method according to the present invention.

FIG. 4 is a flowchart showing a cutting step of the method of the present invention.

FIG. 5 is a schematic explanatory view showing an outline of a continuous casting facility and a conventional slab cutting procedure.

6A and 6B are explanatory diagrams showing a conventional method for cutting a slab having a variable width portion, wherein FIG. 6A shows an example of forward Y variable and FIG. 6B shows an example of reverse Y variable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 2 Slab 3 Cutting machine 4 End face detector 5 Cutting crater 6 End face detection position 7 Cutting start position

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Michio Kobuki 1 Kimitsu, Kimitsu City, Chiba Prefecture Inside Nippon Steel Corporation Kimitsu Works

Claims (3)

[Claims] In a method for cutting a slab cast by a continuous casting equipment provided with a mold width varying device to a fixed size by a cutting machine synchronized with the movement of the slab in a cutting zone, the slab is to be cut. If the location falls within the range of the slab width variable section, change the cutting speed section of the cutting crater or adjust the cutting start position in the slab width direction in advance according to the state of the width variable section and the taper angle. And a cutting operation is started to cut the slab having the variable width portion. 2. When the slab end face detector of the cutting machine detects the variable width section when the variable width section is positive Y variable, the cutting speed section of the cutting crater is changed to a distance corresponding to the taper angle of the variable width section. 2. The method for cutting a slab according to claim 1, wherein the cutting is started only after the expansion. 3. When the slab end face detector of the cutting machine detects the variable width portion when the variable width portion is reverse Y variable, the taper angle of the variable width portion is directed toward the cutting crater outward in the slab width direction. 2. The method of cutting a slab according to claim 1, wherein the cutting is started after moving by a distance corresponding to the distance.