JP2003080356A - Method for gas-cutting continuously cast material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for gas-cutting a continuously cast material with which gas cutting-off device can automatically be driven and the continuously cast material can surely be cut off at each cutting-off portion in the length direction. SOLUTION: Thermal-state at each cutting-off planned position in the length direction of the continuously cast material is grasped before cutting off, and based on this thermal-state, the maximum cutting-off velocity at each cutting-off planned position in the length direction of the continuously cast material, is decided and when the continuously cast material at each cutting-off planned position in the length direction is cut off, in the cutting-off velocity which does not exceed the maximum cutting-off velocity at each cutting-off planned position, a blowpipe is shifted along the width direction of the continuously cast material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas cutting method for a continuously cast material capable of reliably cutting the continuously cast material.

[0002]

2. Description of the Related Art A gas cutting device installed in a continuous casting facility normally blows a gas oxygen flame from a blow tube onto the continuous cast material to cut the continuous cast material. In recent years, in a continuous casting facility, the casting speed has been increased in order to improve the productivity, and accordingly, the cutting speed of the continuous cast material has also been increased.

In the continuous casting equipment, the gas cutting section A (that is, the movable range of the carriage) is usually determined to have the maximum length.
The cutting of the continuous cast material must be completed within the time that the continuous cast material moves. Therefore, if the casting speed is increased, the speed at which the blow tube 2 is moved in the width direction of the continuously cast material must be increased accordingly.

When the cutting speed of the continuous casting material is increased to an inappropriate speed, a cut-out portion D as shown in FIG. 5 (a) is formed in the continuous casting material S, and cutting failure of the continuous casting material occurs. FIG. 5A is a schematic view of a cut surface of the continuous cast material S during cutting, and FIG. 5B is a schematic view of a normal cut surface of the continuous cast material S at the end of cutting. C is a normal cut portion, F is an uncut portion, and there is no uncut portion D in FIG.

Here, v is the cutting speed of the continuous casting material S, and when the cutting speed v (m / s) of the continuous casting material S exceeds the maximum cutting speed v _max (m / s), It is known that the remaining portion D occurs in the continuously cast material S. The cutting speed v (m / s) of the continuous cast material S is the width B of the continuous cast material S in the blow pipe 2 in the continuous casting equipment as shown in FIG.
It is the moving speed for moving along the width B direction from the end portion to the meat point near the center of the width B.

By the way, in such continuous casting equipment,
The high speed casting of the continuous cast material S, the continuous cast material
Continuous casting material to prevent cutting failure of
The maximum moving speed of the blow tube 2 during cutting of the
Maximum cutting speed v of continuous cast material S _max(M / s) is empirical
Was decided. In FIG. 1, 1 is a gas cutting device
It is a device body, and the device body 1 is provided with a blow tube 2,
The wheels 3 allow traveling. Continuous casting material S is
It is conveyed on the table roll 15 at a predetermined conveying speed in the X direction.
Has been. In addition, 12 is a mold 13, 14 is respectively
A pinch roll and a support roll 14.

Symbols a _{i + 1} , a _{i + 2} , a _{i + 3} ... Show schematically the planned cutting positions in the length direction of the continuous casting material S, and the symbol a _i indicates the cutting The position is schematically shown. A is a gas cutting section, and T is a starting point of the gas cutting section. In the continuous casting equipment as described above, in order to cut the continuous casting material S based on the empirically determined maximum cutting speed v _max (m / s) of the continuous casting material S, for example, Under operating conditions where the temperature becomes low, the uncut portion D may occur in the continuous cast material S.

A gas cutting method when such an uncut portion D occurs in the continuously cast material S is disclosed in, for example, Japanese Patent Laid-Open No. 58-20296.
No. 0 publication. This gas cutting method uses a gas cutting device equipped with a cutting failure detector, and when cutting failure is detected by the cutting failure detector at the time of cutting, the blow pipe is automatically returned to the normal cutting portion and the uncut portion is cut. I am trying to disconnect again.

[0009]

However, in such a gas cutting method for performing the gas cutting again, the time from the detection of a cutting failure until the blow pipe is returned to the normal cutting portion and the uncut portion are re-cut. If it takes a long time and the uncut portion extends over a wide range, the gas cutting cannot be completed in the gas cutting section A, cutting trouble may occur, or the recutting condition of the gas cutting device may be generated. However, there is a drawback in that an operator is required to set the above, and the unmanned operation of the gas cutting device cannot be performed.

An object of the present invention is to eliminate the above-mentioned problems, and the gas cutting device can be operated automatically.
Another object of the present invention is to provide a gas cutting method for a continuous casting material capable of reliably cutting the continuous casting material at each of the planned cutting positions in the length direction.

[0011]

A gas cutting method for continuously cast slabs according to the present invention is a method for gas cutting a continuously cast material by blowing a gas oxygen flame from a blow tube onto the continuously cast material. In, in order to grasp the thermal situation at each planned cutting position in the longitudinal direction of the continuous casting material before cutting, the maximum cutting speed at each planned cutting position in the longitudinal direction of the continuous casting material based on this thermal situation. When cutting the continuous casting material at each of the planned cutting positions in the length direction,
The blow pipe is moved along the width direction of the continuous cast material at a cutting speed that does not exceed the maximum cutting speed at each planned cutting position.

At this time, the thermal condition is set to an actual measurement temperature obtained by detecting the temperature of the continuous casting material, or based on the relationship between the temperature and the casting parameter of the continuous casting material prepared in advance. Therefore, it is preferable that the predicted temperature is obtained by predicting the temperature of the continuous cast material.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a layout of essential parts of a continuous casting facility suitable for applying the present invention. The left side in FIG. 1 is the upstream side of the continuous casting equipment, and the right side in FIG. 1 is the downstream side thereof. A mold 12, a pinch roll 13, and a support roll 14 are arranged on the upstream side of the continuous casting equipment, and an apparatus main body 1 of a gas cutting apparatus including a table roll 15 and a blow tube 2 is arranged on the downstream side of the continuous casting equipment. Are arranged. In the illustrated example, the apparatus body 1 of the gas cutting apparatus is of a trolley type, and can be driven by wheels 3 which are rotationally driven. In the present invention, the gas cutting device is not limited to the truck system.

At the time of casting, the continuously cast material S cast in the mold 12 is pulled out by the pinch roll 13, rotatably supported by the support roll 14, and subsequently conveyed on the table roll 15 while advancing in the arrow X direction. A gas cutting device equipped with the blow pipe 2 cuts the material at predetermined cut positions in the longitudinal direction so as to have a predetermined length. In FIG. 1, the continuous cast material S is cut at the position a _i in the length direction. In the continuous casting facilities, before the next cut position a _{i + 1} in the continuous casting material S comes to the starting point T of gas cutting section A, completed cleavage at position a _i in the gas cutting section A,
Next, the apparatus body 1 returns to the starting point T, stands by at that position, and when the next planned cutting position a _{i +} 1 of the continuous casting material S reaches the starting point T, the apparatus body 1 conveys the continuous casting material S. It is configured to travel in synchronization with the speed.

In order to detect online that the planned cutting position a _{i + 1} or the like in the length direction of the continuous cast material S reaches the starting point T of the gas cutting section, for example, an online detector such as a measuring roll is used. By detecting the length of the continuously cast material and the position of the cutting device in the traveling direction, the time when the starting point T is reached can be accurately detected. In the present invention, the thermal condition of the continuously cast material to be cut is grasped, and the maximum cutting speed at each planned cutting position of the continuously cast material is determined based on this. The gas cutting of the continuously cast material is to blow the oxygen gas to the high temperature continuously cast material to melt and cut the continuously cast material by the heat generated by oxidation at that time. Therefore, the higher the heat content of the continuous cast material (that is, the higher the temperature), the more
It enables cutting at a high speed.

The thermal condition of the continuously cast material as understood in the present invention means such heat content itself or an index that can represent this. In general, a continuously cast material after casting has a higher temperature inside and a lower surface temperature, so that it is difficult to measure the heat content itself from the outside. However, in many cases, if the casting conditions are determined, there is a certain correlation between the surface temperature and the heat content of the continuously cast material, so the surface temperature can be used as a specific index of the thermal situation. For example, in the example shown in FIG. 2, the apparatus body 1 is provided with a radiation thermometer 4 that detects the radiant light from the continuous cast material S and measures the surface temperature of the continuous cast material.

In the present invention, the radiation thermometer 4 is used as an example.
For example, when the device body 1 is waiting at the starting point T,
Next expected cutting position a in the length direction of the cast material S_{i + 1}of
Surface temperature immediately before, that is, in FIG. 1, continuous cast material
Position a in the longitudinal direction of S_{i + 1}And a _iBetween the
Fixed position a_{i + 1}The surface temperature in the vicinity is detected and the continuous cast material S
Position a in the length direction_{i + 1}Measured temperature in. Measured temperature
About 10 points were detected in the length direction of the continuous cast material S.
It may be an average value of temperature.

Based on the measured temperature thus obtained, for example, as shown in FIG. 3, the surface temperature of the continuous cast material S and the maximum cutting speed v _{max of} the continuous cast material S, which are predetermined by experiments, are set.
The maximum cutting speed v _max (m / s) at the planned cutting position a _{i + 1} is determined from the relationship of (m / s). Next, when the planned cutting position a _{i + 1} reaches the starting point T, the traveling of the apparatus main body 1 is started, and the blow tube 2 is cut at the maximum cutting speed v determined above.
_The blow pipe 2 is moved in the width direction of the continuous cast material S at a cutting speed v (m / s) that does not exceed _max (m / s).

Here, the pair of blow pipes 2 are located outside the width B end of the continuous cast material S, and when the planned cutting position in the length direction of the continuous cast material S comes, the oxygen gas flame is continuously blown. While spraying on S, it moves from the end of width B to the meat point near the center of width B to cut the continuous cast material S, the movement speed becomes 0, and the movement is stopped temporarily, and then an oxygen gas flame is generated. The continuous casting material S is not cut so that it returns to the outside of the end of the width B of the continuous casting material S from the meat point.

Note that FIG. 3 shows a relationship when a low carbon steel slab having a thickness of 260 mm as the continuous cast material S is gas-cut by using a pair of blow pipes. Following the planned cutting position a _{i + 1} in the length direction of the continuous casting material S, the planned cutting position a _{i + 2} ,
Also for a _{i + 3} ..., The above-mentioned planned cutting position a _{i + 1}
Do the same as. In this way, in the present invention, instead of the conventional method of using the empirically determined maximum cutting speed, the thermal condition at each planned cutting position in the length direction of the continuous casting material before cutting is continuously cast. Grasp the measured temperature obtained by detecting the temperature of the material, determine the maximum cutting speed at each planned cutting position in the length direction of the continuous cast material S based on the measured temperature, and determine the continuous cast material S in the length direction. When cutting at each of the planned cutting positions, the blow pipe is moved in the width direction of the continuous cast material S at a cutting speed that does not exceed the maximum cutting speed. Even if it fluctuates in the vertical direction, the continuous cast material S can be reliably cut.

Of course, from the relationship between the surface temperature of the continuously cast material S and the maximum cutting speed, the maximum cutting speed v at the planned cutting position v
_Since the computer can easily determine the cutting speed v (m / s) that does not exceed _max (m / s), the gas cutting device can be automatically operated. The relationship shown in FIG. 3 is a case where a continuous casting material is gas cut from a low carbon steel slab having a thickness of 260 mm using a pair of blow pipes, but a case where the continuous casting material of another steel type or thickness is gas cut or a steel is used. The same can be applied to the case of gas cutting a steel continuous cast material other than a slab or a metal other than steel. Also in the case of performing gas cutting with one blowing tube, the relationship between the surface temperature of the continuously cast material S and the maximum cutting speed may be determined experimentally.

In the above description, the surface temperature of the continuously cast material is detected by the radiation thermometer 4 provided in the apparatus main body 1 of the gas cutting apparatus, but the temperature detection means of the continuously cast material used in the present invention is the radiation. The temperature is not limited to the thermometer, and any known temperature detecting means can be used as long as it is a temperature detecting means capable of grasping the thermal condition at each planned cutting position in the length direction of the continuous cast material S before cutting.

The position where the temperature detecting means used in the present invention is installed is not limited to the apparatus main body 1 of the gas cutting apparatus.
It may be any position as long as it can grasp the thermal condition at each planned cutting position in the length direction of the continuous cast material S before cutting. Still further, in the present invention, the temperature of the continuous cast material is detected by using the known temperature detecting means as described above for the thermal condition to be grasped at each planned cutting position in the length direction of the continuous cast material S before cutting. Or the relationship between the temperature of the continuously cast material prepared in advance and the casting parameters, for example, a casting speed having a strong correlation with the surface temperature of the continuously cast material as shown in FIG. The predicted temperature obtained based on the relationship used as a parameter is
It is preferable because the maximum cutting speed at which the uncut portion D is not left in the continuous cast material S can be easily determined. The predicted surface temperature of the continuously cast material is obtained from FIG. 4, and the maximum cutting speed corresponding to this predicted surface temperature can be determined from FIG.

Further, in the present invention, the casting parameters in place of the above casting speed are set as a plurality of operation data obtained in a continuous casting facility, and based on these operation data, the molten metal is poured into the mold and the solidification is completed. Then, by calculating every moment until the starting point of the gas cutting section is reached, the cross-section temperature at each planned cutting position in the length direction of the continuous casting material S is predicted before cutting, and the obtained cross-section at each planned cutting position. The temperature can also be the predicted temperature. At that time, as a plurality of operation data, the temperature of the molten metal injected into the mold, the heat removal amount from the molten metal in the mold, the heat removal amount from the continuous casting material in the cooling zone and various rolls arranged on the downstream side of the mold, etc. You should enter at least the data of.

The present invention is not limited to the continuous casting apparatus shown in FIG. 1, but can be applied to various types of continuous casting apparatuses.

[0026]

According to the present invention, the gas cutting device can be automatically operated, and the continuous cast material can be surely cut. As a result, there is an effect that the continuous cast material can be produced with high efficiency in the continuous casting equipment.

[Brief description of drawings]

FIG. 1 is a layout diagram of a continuous casting facility to which the present invention is applied.

FIG. 2 is a front view showing the configuration of a gas cutting apparatus suitable for use in the present invention.

FIG. 3 is a graph showing an example of the relationship between the surface temperature and the maximum cutting speed of the continuously cast material used in the present invention.

FIG. 4 is an example graph showing the relationship between the casting speed used in the present invention and the surface temperature of a continuously cast material.

FIG. 5 is a schematic view showing a gas cutting situation.

[Explanation of symbols]

S Continuous casting material 1 Main body of gas cutting device 2 Blowing pipe 3 Wheel 4 Radiation thermometer (temperature detection means) 12 Mold 13 Pinch roll 14 Support roll 15 Table roll A Gas cutting section B Width a _i Position during cutting a _{i + 1} , a _{i + 2} , a _{i + 3} ... Planned cutting position

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Makoto Samurai             1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Made in Kawasaki             Chiba Steel Works, Ltd. F-term (reference) 4E004 MC08 MC24 PA10

Claims (3)

[Claims] 1. A continuous casting material gas cutting method for cutting the continuous casting material by blowing a gas oxygen flame from a blow tube to the continuous casting material, wherein each cutting schedule in the length direction of the continuous casting material is cut before cutting. Grasp the thermal situation at the position,
Determine the maximum cutting speed at each planned cutting position in the lengthwise direction of the continuous casting material based on this thermal situation, and when cutting the continuous casting material at each planned cutting position in the longitudinal direction, at each planned cutting position A method of gas cutting a continuous cast material, comprising moving the blow tube along the width direction of the continuous cast material at a cutting speed that does not exceed a maximum cutting speed. 2. The gas cutting method for a continuously cast material according to claim 1, wherein the thermal condition is an actually measured temperature obtained by detecting a temperature of the continuously cast material. 3. The thermal condition is a predicted temperature obtained by predicting the temperature of the continuous cast material based on the relationship between the temperature and the casting parameter of the continuous cast material prepared in advance. The gas cutting method for a continuously cast material according to claim 1.