JPH07113611B2 - Inspection method and inspection device for steel strip butt weld - 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 and an inspection method for inspecting a surface defect of a steel strip butt weld portion which is welded by a welding machine such as a flash butt welding machine and whose surface is processed by a machining machine. It relates to the device.

[0002]

2. Description of the Related Art When connecting butt steel strip ends to each other online with a welding machine such as a flash butt welder (hereinafter referred to as "welder"), a step is formed in the butt weld zone of the steel strip and in the vicinity of the weld zone. If there is a surface defect such as baldness, scratches, or scratches, it will hinder the subsequent steps, so it is necessary to inspect it.

Conventionally, in such inspection, the surface condition of the steel strip is visually inspected before welding, and after the butt welding, the weld bead is machined by a machine (flash trimmer). It was performed by the method of inspecting the processed surface again. If a surface defect is found by inspection and it is determined that the welding is defective, the work is performed in the process of re-welding. Such defects in the welded portion cannot be completely eliminated under the present circumstances. Therefore, it is desired to develop a rapid inspection method for finding the defect in the welded portion.

[0004]

Although a measuring instrument for inspecting a defect of a butt weld portion has existed in the past, the conventional measuring instrument lacks promptness in the online where the inspection is time-limited. Since it cannot be used, there was a problem that it was not possible to quantitatively grasp abnormalities in the welded part.

For this reason, the above-described visual inspection is still used at present. However, since the visual inspection entrusts the judgment to the experience of the inspector, it requires skill and is likely to cause individual differences, and requires personnel for inspection, resulting in personnel cost and loss of time. There were many problems.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to detect a defect in a steel strip butt weld welded by a welding machine such as a flash butt welder automatically, quickly and accurately, and to detect the strip butt weld. To provide an inspection method and an inspection device.

[0007]

In order to achieve the above object, in the inspection method of the present invention, a camera for measuring the difference between the left and right light reflection amounts with respect to the welding line of the steel strip butt welding portion. And a controller for outputting a voltage signal by replacing the difference in the amount of reflection of the light measured by the camera with a voltage change and a ring illuminator. It is provided above the height so as to be able to travel along the welding line, and further, an arithmetic mechanism is provided for comparing the voltage signal value with a preset reference value when there is no welding defect. It is characterized in that a signal value and the reference value are compared and a welding defect is detected based on a difference between the voltage signal value and the reference value. Further, the present invention is characterized in that the camera and the ring illuminator are attached to a tool rest of a machining machine for machining the surface of the steel strip butt weld. Further, the present invention is characterized in that an alarm mechanism is attached to the arithmetic mechanism, and an alarm is issued by the alarm mechanism when a welding defect is detected based on a difference between the voltage signal value and the reference value.

In order to achieve the above object, in the inspection apparatus of the present invention, a constant height of the steel strip for measuring the difference between the left and right light reflection amounts with respect to the welding line of the steel strip butt welds. It is composed of a camera and a ring illuminator provided above the welding line so as to be freely movable, and a controller for replacing the difference in the reflection amount of the light measured by the camera with a voltage change and outputting a voltage signal. And a calculation mechanism for comparing the voltage signal value with a preset reference value when there is no welding defect. Further, the camera and the ring illuminator are characterized in that they are attached to a tool rest of a machining machine for machining the surface of the steel strip butt weld. Further, it is characterized in that an alarm mechanism for issuing an alarm when a welding defect is detected by the difference between the voltage signal value and the reference value is attached to the arithmetic mechanism.

A known sensor is used as the visual sensor. Therefore, although a detailed description thereof will be omitted, this visual sensor reads with a camera by a method of comparing the area integral value of the light amount on the two areas A and B formed by dividing the area designated by the pointer into two. It has a function of collectively processing image information (three-dimensional) including the brightness of each point of the dimension (area) by an analog method. The basic algorithm is to set an image of the target object that is flowing normally in advance and compare it with the target object that will flow next time at ultra-high speed.Pattern recognition of colors and shapes, detection of minute color difference Is possible. The ring illuminator is a ring-shaped fluorescent lamp using a high frequency power supply.

Next, the present invention will be described with reference to the drawings. 1 is a perspective view for explaining the principle of the present invention, and FIG. 2 is a front view showing a state in which a camera is attached to a tool rest.
In FIG. 1, 6 is a steel strip, and 7 is a welding line of a steel strip butt weld. The visual sensor 1 includes a camera 2 and a controller 3. The camera 2 of the visual sensor 1 and the ring illuminator 9 are provided above a certain height of the steel strip 6, and while maintaining this height, along the welding line 7, the steel strip 6
In the plate width direction, the steel strip can travel from one end to the other end of the steel strip, and the amount of light reflected from the area 4 of the welded portion of the light emitted from the ring illuminator 9 is detected. The controller 3 has a mechanism that replaces the signal of the light reflection amount detected by the camera 2 with a voltage change to obtain a voltage signal. Reference numeral 8 is a calculation mechanism connected to the controller 3. The calculation mechanism 8 has a function of comparing a voltage signal (measured value) output from the visual sensor 1 with a preset reference value when there is no welding defect.

As shown in FIG. 2, the camera 2 of the visual sensor 1 is attached to a tool rest 5 of a machining machine (flash trimmer) provided at the rear of the welding machine. The tool rest 5 has a mechanism that moves in the plate width direction of the steel strip 6 (the direction shown by the arrow in FIG. 2) when machining the surface of the butt welded portion. Camera 2 on this turret 5
By attaching the ring illuminator 9 and the ring illuminator 9, the camera 2 and the ring illuminator 9 can move along the welding line 7 above a certain height of the steel strip 6, and while machining the welded portion with the tool rest 5. It is possible to inspect the machined surface. Reference numeral 9 is a lamp of a light source, and the camera 2 is running.
It is a ring illuminator attached to the tool rest 5 so that the area 4 can be always illuminated by following.

The camera 2 can be attached not only to such a tool rest 5, but also to one having a mechanism capable of moving along the plate width direction of the steel strip 6 as appropriate or to attach it externally. Alternatively, such a moving mechanism may be installed.

Next, the process of inspecting the steel strip butt weld according to the present invention will be described. FIG. 3 is an explanatory view showing the detection area, and FIG. 4 is a flowchart explaining the inspection process of the present invention. As the visual sensor 1, a known one is used as described above. The center line of the visual sensor 1 which divides the area 4 into two areas A and B is aligned with the welding line 7 by the pointer 10 and positioned. Next, the right and left areas A and B having the same area are irradiated with desired light by the light source 9. Next, the camera 2 is moved along the welding line 7 from one end to the other end of the plate width, and the light reflection amounts of the left and right areas A and B moving along with the camera 2 along the welding line 7 are detected and the difference between them is detected. To judge.

Specifically, it is determined whether the amount of light on the left and right of areas A and B is symmetrical or asymmetrical with respect to the welding line 7 with which the steel strips 6 are butted. That is, if the amount of light is asymmetric with respect to the welding line, the width of the cutting surface becomes different, and this becomes a difference in area, which appears as a difference in the shapes of areas A and B (unevenness of the cutting surface). Alternatively, when the color of the cut surface is bad, the difference in brightness appears and appears as the color difference between areas A and B. In this way, the symmetry of the areas A and B is determined from the shape and the lightness (color difference).

Since the camera 2 is mounted on the tool rest 5, the inspection is performed while the steel strip butt weld is machined by the tool rest 5. That is, the state immediately after machining can be inspected. Then, when a difference occurs in the reflection amount of light in the areas A and B, it is output as an analog amount. Further, this output is compared with a preset reference value when there is no welding defect, and if this difference is equal to or higher than a predetermined level, an alarm 11 is issued and this is output to the recorder.

FIG. 5 is a process chart showing the contents of the processing in the operation mechanism of the voltage signal detected by the visual sensor. In the first example of the processing, the brightness difference between areas A and B,
The difference in shape is detected, and the value (X) obtained by absolute value processing is compared with the reference value (X ₀ ). If the value is equal to or higher than a predetermined level, an alarm 11 is generated and the recorder 12 Output to. Further, in the second example of the processing, the difference in brightness and the difference in shape between the areas A and B are detected, and the absolute value processed value (X) is integrated over the entire width of the board (ΣX), and this value is calculated. Divide by the board width (W). Then, the value is compared with a reference value, and when the value is equal to or higher than a predetermined level, an alarm 11 is issued, and when the alarm is generated, it is output to the recorder 12. FIG. 5 shows a case where the above two examples are used in combination.
The determination may be made by any of the examples.

[0017]

Embodiments of the present invention will be described below. Inspection of a steel strip butt weld having a finishing width (d) of 12 mm after processing by a welding machine was carried out by the inspection apparatus of the present invention shown in FIGS. 1 and 2. The height (a) from the steel strip 6 to the camera 2 was 61 mm, the width (b) of the area 4 was 8.4 mm, and the length (c) was 6.3 mm. Then, the test pieces Nos. 1 to 5 in which a defective portion such as a stepped edge, an entire stepped portion, or a stepped portion in the central portion was observed in the steel strip butt welded portion were inspected. The inspection measures the brightness and shape of areas A and B of the same area with the welding line 7 as the center line (10000 screens / second), outputs the brightness difference as an analog amount ± 10 V, and records it with a recorder (pen recorder) 12. did. FIG. 6 is a graph showing the results. The left and right of the graph show the width direction of the steel strip 6, and the horizontal axis of the central part shows the reference line of zero voltage. As shown in FIG. 6, each defect existing in the sample Nos. 1 to 5 is recorded by a pen recorder, and an alarm is generated at a portion where the output exceeds a certain reference value indicated by an arrow in the figure, so that a welding defect is generated. It can be seen that is detected.

[0018]

As described above, according to the present invention, it is possible to automatically, quickly, and accurately detect the surface defect of the steel strip butt welding portion whose surface is machined by the machining machine. This brings about a useful effect.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating the principle of the present invention.

FIG. 2 is a front view showing a state in which a camera is attached to a turret.

FIG. 3 is an explanatory diagram showing areas detected by a visual sensor.

FIG. 4 is a flow chart illustrating an inspection process of the present invention.

FIG. 5 is a process diagram showing the contents of processing in a calculation mechanism of a voltage signal detected by a visual sensor.

FIG. 6 is a graph showing the results of the example by a pen recorder.

[Explanation of symbols]

 1 Vision Sensor 2 Camera 3 Controller 4 Area 5 Turret 6 Steel Strip 7 Welding Line 8 Arithmetic Mechanism 9 Ring Illuminator 10 Pointer 11 Alarm 12 Recorder

Front page continuation (72) Inventor Takashi Shimada 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Hirofumi Nojima 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo In-house (72) Inventor Masanori Shinohara 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (56) Reference JP-A-2-158880 (JP, A) JP-A-60-259938 (JP , A) JP-A-3-189083 (JP, A) JP-A-60-135705 (JP, A)

Claims (6)

[Claims] 1. A camera for measuring a difference in light reflection amount between left and right with respect to a welding line of a steel strip butt weld, and a difference in the light reflection amount measured by the camera is replaced with a voltage change. The camera and the ring illuminator of the visual sensor constituted by the controller for outputting the voltage signal and the ring illuminator of the light source for irradiating the welding surface are allowed to travel along the welding line above a certain height of the steel strip. Further, a calculation mechanism is provided for comparing the voltage signal value with a preset reference value when there is no welding defect, and the calculation mechanism compares the voltage signal value with the reference value to obtain the voltage. A method for inspecting a steel strip butt weld, wherein a welding defect is detected based on a difference between a signal value and the reference value. 2. The method for inspecting a steel strip butt weld according to claim 1, wherein the camera is attached to a tool rest of a machining machine for machining the surface of the steel strip butt weld. 3. The steel strip butt welded portion according to claim 1, wherein an alarm mechanism is attached to the arithmetic mechanism, and the alarm mechanism issues an alarm when a welding defect is detected based on a difference between the voltage signal value and the reference value. Inspection method. 4. A steel strip butt-welded portion is provided so as to be movable along the welding line above a certain height for measuring the difference between left and right light reflection amounts with respect to the welding line. A visual sensor configured by a camera, a controller for outputting a voltage signal by replacing a difference in the reflection amount of the light measured by the camera with a voltage change, a ring illuminator for illuminating a welding surface, and the voltage signal value. And an arithmetic mechanism for comparing a preset reference value when there is no welding defect, with a steel strip butt weld inspection device. 5. The apparatus for inspecting a steel strip butt weld according to claim 4, wherein the camera is attached to a tool rest of a machining machine for machining the surface of the steel strip butt weld. 6. The steel strip butt welded portion according to claim 4, wherein the arithmetic mechanism is provided with an alarm mechanism for issuing an alarm when a welding defect is detected based on a difference between the voltage signal value and the reference value. Inspection equipment.