JP2012045601A - Method for detecting burr of slab, and slab treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a burr detecting method for detecting presence/absence and the size of any burr formed locally or over the entire length in the width direction of a slab section by a simple and inexpensive method, and to provide a slab treatment method thereafter.SOLUTION: In the burr detecting method for detecting burrs formed on a lower end of a cut section of a slab which is cut to the prescribed length after the continuous casting and conveyed on a roller table, the vertical fluctuation when the slab passes on one roll out of a roll group constituting the roller table is detected by any one means out of a contact detection sensor, a light quantity sensor and a distance meter, and when the fluctuation amount exceeds the prescribed value, or when the changing time of the vertical fluctuation is within the prescribed value in addition to the vertical fluctuation amount of the slab, it is determined that there are burrs.

Description

  The present invention relates to a method for accurately detecting burrs generated on a cut surface of a steel slab cut to a predetermined length on the exit side of a continuous casting machine, and a subsequent slab processing method.

The steel slab discharged from the continuous casting machine is cut to a predetermined length with a fusing torch installed on the outlet side of the continuous casting machine, and given a production number, etc. It is conveyed to the hot rolling process.
However, in the above-described fusing, the molten steel may remain attached to the lower end portion of the cut surface and form burrs (also referred to as sagging). This burr is not a problem when it is small. However, in ultra-low carbon steel, the size of burrs can be as high as 40 to 50 mm. If hot rolling is performed as it is, the rolling roll is damaged or the damaged part is transferred to the product. It may harm the surface quality of the.

  Therefore, the slab cut on the outlet side of the continuous caster is used for hot rolling, for example, when attaching a production number immediately after cutting, etc., using means such as hot-cutting, grinding, cutting, crushing, etc. The burr is removed. However, the above-described deburring alone does not necessarily remove the deburring completely, and there are cases where there is no deburring device, or deburring may not be performed due to a failure of the device. Therefore, it is necessary to confirm that burrs have been removed to a predetermined value or less by measuring the presence or absence of burrs occurring in the slab and the size of the burrs before hot rolling.

  As a method for measuring the size of a burr, conventionally, it has been often determined visually. However, since the slab after continuous casting is hot, visual inspection is a dangerous operation, and it has become difficult to place an inspector on site from the viewpoint of improving productivity.

  Therefore, the size of the burr is determined by observing the cut surface in an operation room or the like based on an image captured by a television camera. However, the method for inspecting the presence or size of burrs based on TV images is because the TV image changes depending on the shape of the burrs and the imaging conditions (product temperature, influence of external light, shooting position, etc.). It is difficult to detect the size of burrs with high accuracy. In addition, since many slabs must be inspected in a short time, the work burden for the inspector is large.

  As a technique for solving the above-described problem, Patent Document 1 discloses that instead of a visual inspection by a human, a slab end surface (cut surface) including a burr is illuminated with an illuminating device and a shadow of the burr is photographed with an imaging device. A technique for processing the image signal from the imaging device to determine the presence or absence of burrs is disclosed.

JP 07-159346 A

  However, since the method of inspecting burrs using the image processing apparatus of Patent Document 1 relies on the image for the determination process of the presence or absence of burrs, there is a problem that the detection accuracy decreases when the environment around the imaging apparatus deteriorates. The equipment is also large and expensive, so it is difficult to adopt.

  Accordingly, an object of the present invention is to provide a burr detection method capable of detecting the presence / absence and size of a burr generated in the width direction of a slab cross section or a locally generated baffle by a simple and inexpensive method, and subsequent slab processing. To propose a method.

  The inventors have intensively studied to solve the above problems. As a result, when the burr formed by cutting is large when the slab discharged from the continuous casting machine is cut by a fusing torch or the like and then conveyed on the roller table, the roller table, particularly the roller Focusing on the fact that the slab largely fluctuates in the vertical direction when passing over the rolls constituting the table, a method for inspecting burrs from this vertical fluctuation has been studied and the present invention has been developed.

  That is, the present invention is a method for detecting burrs formed at the lower end of the cut surface of a slab which is cut to a predetermined length after continuous casting and is conveyed on the roller table, and includes a group of rolls constituting the roller table. We propose a burr detection method that detects vertical fluctuation when a slab passes over one of the rolls and determines that there is burr when the fluctuation amount exceeds a predetermined value.

  The burr detection method of the present invention is characterized by determining that there is a burr when the change time of the vertical fluctuation is within a predetermined value in addition to the vertical fluctuation amount of the slab.

  The burr detection method of the present invention is characterized in that the means for detecting the vertical fluctuation of the slab is any one of a contact detection sensor, a light amount sensor, and a distance meter.

  The present invention also proposes a slab processing method characterized in that the next step of the slab is determined based on the determination result obtained by the above-described burr detection method.

  According to the present invention, it is possible to accurately detect the presence and size of burrs formed at the lower end of the cut surface during slab cutting with a simple and inexpensive method, which contributes to improvement in slab quality and productivity. can do.

It is a figure explaining the principle of the burr | flash detection method of this invention. It is a figure explaining the vertical fluctuation of the slab by curvature. It is a figure explaining the burr | flash detection method using a contact detection sensor. It is a figure explaining the burr | flash detection method using a light quantity sensor. It is a figure explaining the burr | flash detection method using a distance meter. It is a figure explaining the slab processing method of this invention.

First, the basic principle of the burr detection method of the present invention will be described.
FIG. 1 shows a state in which a slab 1 cut to a predetermined length is being transported on a roller table 2. FIG. 1 (a) shows that a slab tip having a burr 3 at the lower end of the cut surface is a roller. The state in front (rear) of one roll A in the roll group constituting the table, (b) is the state in which the slab tip is on the center line of roll A, and (c) is the slab tip. Shows a state in which passes through the center line of roll A. As can be seen from FIG. 1, when the tip of the slab where the burr is generated is on the center line of the roll A, that is, when the state of (b) is reached, the slab is upward compared to the state of (a). Move to. And when the slab front-end | tip part which the burr | flash generate | occur | produced passes the center line of the roll A, a slab will move below and will be in the state of the original (a). Since the amount of fluctuation in the vertical direction changes according to the size of the burr, it is possible to detect the size of the burr by measuring the amount of vertical fluctuation of the slab. In addition, with this method, the amount of vertical fluctuation of the slab depends on the maximum burr height, so it is possible to detect the presence or absence of burr even if the burr occurrence position is local in the width direction. It is.

  By the way, the cast slab is not necessarily flat in the length direction and sometimes warps. In such a case, as shown in FIG. 2, the vertical fluctuation appears to be the same as the occurrence of burrs. However, the vertical movement of the slab due to burr occurs in a short time when the burr portion passes over the center line of the roll, whereas the vertical movement of the slab due to warpage occurs very slowly. Therefore, it is possible to identify whether it is a burr or a warp at the time when the vertical fluctuation occurs. For example, when the moving speed of the slab is v (m / s) and the roll diameter is D (m), the vertical fluctuation time is within the time t (= D / v) required to pass on the roll. Can be identified as a burr, and warp when the time is longer. The above threshold value is merely an example, and can be shortened or lengthened as appropriate. In addition, you may identify with the speed of up-and-down fluctuation instead of changing time.

Further, in the above description, the case where burrs are generated at the front end portion in the slab transport direction has been described as an example, but the case where burrs are generated at the rear end portion in the slab transport direction is also determined in the same manner. be able to.
The present invention has been completed by further studying the above findings.

Next, means for detecting the vertical fluctuation of the slab in the burr detection method of the present invention will be described.
There are various methods for detecting the vertical fluctuation of the slab, but any method can be used as long as it can detect the vertical fluctuation of the slab, and there is no particular limitation.
For example, as the simplest method, as shown in FIG. 3, on the roll of the roll A of the roller table through which the slab passes, preferably D / 2 from the center line to the center line of the roll (where D: roll There is a method in which a contact detection sensor 5 such as a lever-type limit switch is installed above a range about (diameter) backward. In this case, if the lower end of the lever is set at a height (slab thickness + allowable amount of burr) from the upper surface of the roll, when a slab having a burr exceeding the allowable amount passes over roll A, the slab contacts the lever. And burr can be detected. The lever-type switch may be a type that is turned on and off by contact, but a switch that can measure the amount of vertical fluctuation of the slab from the change in the angle of the lever due to contact with the slab may be used.

  Also, FIG. 4 shows that light such as visible light or infrared light is emitted as signal light from the light projecting unit, and the light receiving unit detects a change in the amount of light blocked by the detection object (transmission type) or receives reflected light. As shown in FIG. 3, the light quantity sensor 6 that is detected by a part (reflective type) and obtained as an output signal is preferably D from the center line to the center line of the roll on the roll A of the roller table through which the slab passes. This is an example in which it is installed at a height of (slab thickness + allowable amount of burrs) behind the upper surface of the roll about / 2 (however, D: roll diameter). In the case of this example, the vertical fluctuation amount of the slab can be detected from a change in the transmission amount or the reflected light amount of the signal light emitted from the light projecting unit. When using a light amount sensor, a plurality of light amount sensors are installed in the height direction, and the presence or absence and the amount of fluctuation of the slab are detected from changes in the light shielding amount or reflected light amount of each sensor. Good.

  Further, FIG. 5 shows a distance meter 7 that measures the distance between two points in a non-contact manner by measuring the time until the object is irradiated with a laser beam or a long sound wave and reflected and returned. As in FIG. 3, an example in which the slab is installed on the roll of the roll A of the roller table, preferably above the center line of the roll to D / 2 (where D is the roll diameter) rearward from the center line is shown. It is a thing. In the case of this example, the presence / absence and amount of fluctuation of the slab up and down can be detected quantitatively and accurately as a change in the distance between the distance meter and the upper surface of the slab, and is the most preferable detection method.

  The means for detecting and measuring the vertical fluctuation of the slab shown in FIGS. 3 to 5 may be installed in at least one place in the slab width direction, but preferably installed in two or more places. Is desirable. The detection means that can be used in the present invention is not limited to the above example.

Next, the slab processing method of the present invention will be described.
The slab was cut to a predetermined length on the exit side of the continuous casting machine, passed through a deburring process, and then the slab was measured for the presence and size of burrs by the burr detection method of the present invention. The next process for transporting is determined. Specifically, as shown in FIG. 6, the burr detection method of the present invention is used to determine the presence / absence of burrs and measure the size. If the product is evaluated as being within the range, the transport command to the next process such as the hot rolling process is issued as it is. Or issue a conveyance command to the maintenance process of removing burrs with a peeling machine, chipping machine, grinder or the like. When the inspection device is in the vicinity of the deburring device, it may be sent back to the deburring device after the inspection.

  The technique of the present invention is not limited to a method for detecting burrs generated on a slab cut surface, and can also be applied as an inspection method for other materials in which similar defects occur due to fusing, mechanical cutting, or the like. .

1: Slab 2: Roller table A: Roll constituting the roller table 3: Burr (sag)
4: Warpage 5: Contact detection sensor 6: Light quantity sensor 7: Distance meter

Claims (4)

A method for detecting burrs formed at the lower end of a cut surface of a slab which is cut to a predetermined length after continuous casting and is conveyed on a roller table, on one roll of a group of rolls constituting the roller table A burr detection method that detects vertical fluctuation when the slab passes through and determines that there is burr when the fluctuation amount exceeds a predetermined value. 2. The burr detection method according to claim 1, wherein in addition to the vertical fluctuation amount of the slab, it is determined that there is a burr when a change time of the vertical fluctuation is within a predetermined value. 3. The burr detection method according to claim 1, wherein the means for detecting the vertical fluctuation of the slab is any one of a contact detection sensor, a light amount sensor, and a distance meter. A slab processing method, wherein the next step of the slab is determined based on the determination result obtained by the burr detection method according to any one of claims 1 to 3.

Images