JP3071595B2 - Diagnosis method of surface layer inclusion detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing a slab surface layer inclusion detecting device for detecting an abnormality of a detecting device for detecting the distribution state of a slab surface layer inclusion from a luminance distribution of a molten pool image. .

[0002]

2. Description of the Related Art Conventionally, a detecting device for detecting surface layer inclusions in a billet has been disassembled and inspected off-line. Since this inspection is performed periodically, it is difficult to detect abnormalities during operation of the detection device.If an abnormality occurs in the detection device, sparks caused by surface slab inclusions may be over-detected or may not be detected. There was a problem that quality troubles frequently occurred due to surface inclusions.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to detect an abnormality in a detector for detecting inclusions on a steel slab surface on-line and eliminate a quality problem caused by the abnormality in the detector.

[0004]

SUMMARY OF THE INVENTION The present invention provides a molten pool image obtained by imaging a molten pool formed by ablating a surface of a billet.
Is differentiated in the width direction of the molten pool, while measuring the sparks caused by the surface layer inclusions from the brightness distribution of the obtained differential weld pool image ,
The luminance distribution of the molten pool image is continuously measured, and the abnormality of the detection device is detected from the temporal variation of the measured luminance distribution, and the maximum luminance amount and the minimum luminance amount of the differential molten pool image are detected.
And a difference function of the imaging device is also measured to check the differentiation function of the imaging device .

[0005]

According to the present invention, the luminance distribution of the molten pool image is continuously measured while measuring the distribution of the surface slab inclusions from the luminance distribution of the differential molten pool image obtained by the imaging device having a differentiating function. By measuring the brightness distribution over time by measuring online, the lens
An abnormality such as dirt can be immediately detected. Also this
At the same time, the maximum and minimum luminance of the differential weld pool image
The difference of the function of the imaging device from the difference
be able to.

[0006]

Next, the present invention will be described in detail with reference to the illustrated embodiment. Reference numeral 1 denotes an imaging device attached to a traveling vehicle 2. The imaging device 1 reciprocates by the traveling vehicle 2 to image the molten pool 3 on the surface layer of the slab. In addition, the imaging device 1
The brightness distribution of the image of the weld pool 10 taken in the x-axis direction
A differentiating function is provided to increase the spark detection accuracy by performing differential processing (in the width direction of the molten pool 3) . 4 is the traveling vehicle 2
Is a traveling platform that guides reciprocally. Reference numeral 5 denotes a crater for cutting a billet to be attached to the traveling vehicle 2.
The surface layer of steel slab 6 is cut by the combustion flame of oxygen and LPG radiated from the surface. Reference numeral 7 denotes a spark detection device that receives the differential weld pool image 11 that has been differentiated by the differentiation function of the imaging device 1 and measures the brightness distribution of sparks caused by the surface slab inclusions.

Reference numeral 8 denotes a luminance distribution of the molten pool image 10 and a luminance distribution of the differential molten pool image 11 captured by the imaging device 1 which are continuously input to detect an abnormality of the imaging device 1 from a temporal change in the luminance distribution. The diagnostic device 8 performs a brightness distribution section 12 of the molten pool image 10 in which no spark is generated.
, The maximum luminance amount A is continuously measured to determine whether or not the luminance distribution is abnormally changed, and the amount of water vapor applied to the imaging device 1 and the contamination of the lens of the imaging device 1 are inspected.
This is because the maximum luminance amount A of the molten pool image 10 is substantially constant except for the fluctuation of the light amount of the molten pool 3. This is to judge that disturbance and lens fouling have occurred.

The diagnostic apparatus 8 performs a differential processing of the luminance distribution of the molten pool image 10 by differentiating the luminance distribution of the molten pool image 10.
3, the weld pool width B is continuously measured to check whether the field of view of the imaging device 1 has shifted from the weld pool 3. Since the width of the molten pool 3 is substantially constant, when the molten pool width B of the brightness distribution cross section 13 fluctuates beyond a threshold value, it is determined that a shift has occurred in the visual field of the imaging device 1. is there.

Further, the diagnostic apparatus 8 calculates the difference between the maximum luminance C due to sparks and the minimum luminance D due to light emission from the molten pool 3 from the luminance distribution cross section 13 of the differential molten pool image 11 obtained by differentiating the luminance distribution of the molten pool image 10. Is measured to check the differential function of the imaging device 1. When the difference between the maximum luminance amount C and the minimum luminance amount D is equal to or smaller than the threshold value, it is determined that an abnormality has occurred in the differentiation function of the imaging device 1. Reference numeral 14 denotes a conveying roll provided between the traveling gantry 4 for feeding a billet.

[0010] With the above-described structure, the surface layer of the billet 6 fed through the transport roll 14 is radiated from the crater 5 attached to the traveling carriage 2 guided by the traveling gantry 4. Cutting is performed by the combustion flame of oxygen and LPG. Due to this cutting, the molten pool 3 is generated on the surface layer of the steel slab 6 to emit melting light, and a spark is generated by burning of the inclusions on the surface of the steel slab. This is continuously imaged by the imaging device 1 to obtain a molten pool image 10. This molten pool image 10
Is subjected to a differentiation process by the differentiation function of the imaging device 1, the differentiated weld pool image 11 subjected to the differentiation process is input to the spark detector 7, the brightness distribution of the spark is measured from the differential weld pool image 11, Detect the distribution of surface inclusions.

In this way, the maximum luminance A is continuously measured online from the luminance distribution cross section 12 of the molten pool image 10 input to the diagnostic device 8 while detecting the distribution of the surface slab inclusions. If the measured maximum luminance amount A fluctuates by more than the threshold value, it is determined that the image pickup apparatus 1 has suffered disturbance due to water vapor or lens contamination. When disturbance due to water vapor or lens contamination is minimal, it is only necessary to perform luminance correction based on the fluctuation amount exceeding the threshold value of the maximum luminance amount A to suppress overdetection or non-detection of sparks. If the surface is very dirty, the detection is temporarily stopped or the lens is cleaned.

Further, the differential weld pool image 11 subjected to the differential processing is input to the diagnostic device 8, the weld pool width B is measured from the brightness distribution cross section 13 of the differential weld pool image 11, and the visual field of the imaging device 1 is changed from the weld pool. Inspection is continuously performed online for any deviation. If the molten pool width B exceeds the threshold value, it is determined that a visual field deviation has occurred, the detection is temporarily suspended, and the visual field deviation of the imaging device 1 is determined. Fix it.

Further, the difference between the maximum luminance value C due to sparks and the minimum luminance value D due to light emission from the molten pool 3 is measured from the luminance distribution cross section 13 of the differential weld pool image 11 input to the diagnostic device 8 and the imaging device 1 The differentiation function is continuously inspected online, and when the difference between the maximum luminance amount C and the minimum luminance amount D exceeds the threshold value, it is determined that an abnormality has occurred in the differentiation function and the detection is temporarily stopped. To replace or repair the differentiating circuit of the imaging device 1. In this manner, the abnormality of the imaging device 1 is immediately detected online during the detection of the surface inclusions, so that the distribution state of the steel slab surface inclusions can be always accurately detected without over-detection or non-detection. It is possible to prevent quality troubles properly.

In the embodiment, the detection accuracy is enhanced by differentiating the molten pool image 10 by a differentiating function provided in the imaging device 1 and then measuring the brightness distribution of the spark and the molten pool width. It is a matter of course that the brightness distribution of the spark and the width of the molten pool can be detected directly from the camera, and the differentiation function is provided in the imaging device 1. However, the differentiation function can be separately provided as an image processing device, or the diagnostic device 8 or the spark detection can be performed. Of course, it may be provided in the device 7.

[0015]

As apparent from the above description, the present invention measures the distribution of the surface slab inclusions from the brightness distribution of the molten pool image obtained by the imaging device, and changes the brightness distribution of the molten pool image. Since the abnormal fluctuation of the luminance distribution was detected by continuously measuring online,
Abnormality of the imaging device can be detected online during the detection of steel slab surface inclusions, and in addition to being able to accurately prevent quality problems due to functional abnormalities of the imaging device, etc.
We used the image of the molten pool to detect the inclusions on the slab and the abnormalities of the differential function of the detector using the device, so there is no need to attach a new inspection device. This is an extremely large thing that can be brought to the industry as a method of diagnosing a steel slab surface layer inclusion detection device that has solved the above points.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is an image diagram of a molten pool imaged by the imaging device of the present invention.

FIG. 3 is a cross-sectional view of a brightness distribution of a molten pool image captured by the imaging device of the present invention.

FIG. 4 is a differential weld pool image diagram of a weld pool image captured by the imaging apparatus of the present invention.

FIG. 5 is a luminance distribution cross-sectional view of a differential weld pool image of the weld pool image captured by the imaging apparatus of the present invention.

[Explanation of symbols]

 1 Imaging device 8 Diagnostic device 10 Weld pool image 11 Differential weld pool image

Continuation of the front page (72) Inventor Mitsuru Sakakibara 5-3 Tokai-cho, Tokai-shi, Aichi Prefecture Nippon Steel Corporation Nagoya Works (56) References JP-A-4-350547 (JP, A) JP-A Sho 62 -79322 (JP, A) JP-A-64-47939 (JP, A) JP-A-4-109647 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21/84- 21/958

Claims (1)

(57) [Claims] 1. A weld pool image obtained by imaging a weld pool created by ablating a slab surface is differentiated in the width direction of the weld pool.
Then, while measuring the sparks due to the inclusions on the slab from the luminance distribution of the obtained differential molten pool image, the luminance distribution of the molten pool image is continuously measured, and the temporal variation of the measured luminance distribution < br /> and detects the abnormality of the detection device from moving, differential melt pool
The difference between the maximum and minimum luminance of the image is measured and the
A method for diagnosing a surface slab inclusion inclusion detecting apparatus, which also performs an inspection of a differential function of a device.