JPS59197856A - Welding position detecting device - Google Patents

Abstract

PURPOSE:To detect a position of a true weld zone, and to improve the measuring accurcy by detecting the highest temperature position. CONSTITUTION:An infrared ray radiated from the vicinity of a joint part 3 is reflected by a mirror 9 and condensed to an infrared-ray detector 11 placed at a right angle with a weld zone 3 line of an electric welded tube 4 through a lens 10. An electric signal of a level corresponding to intensity of the infrared ray radiated from the joint part 3 is outputted to the infrared-ray detector 11, and a position signal of the highest temperature of the infrared-ray detector 11 is outputted by a highest temperature position detecting circuit. The highest temperature position point of the electric welded tube 4, namely, the center point of welding can be detected, therefore, an ultrasonic probe 2 can be positioned to the weld zone 3.

Description

Detailed Description of the Invention This OIJ relates to a weld position detection device necessary for positioning the probe of an ultrasonic flaw detection device used when inspecting the quality of welds such as electric resistance welded pipes. It is something.

As a conventional fin detection device, there is a method using light or the like. Here, the conventional test method 'f will be explained using FIG. In Figure 1, (1) is an ITV camera, (
2) is an ultrasonic probe, (3) is a welded part, and (4) is an electric resistance welded tube.

(51/r1 projector, (6) is the signal processing section. Fang 2
The figure is a diagram for explaining a detection device for a welded part (3) using the apparatus shown in FIG. 1. In FIG. 7
).

In Figure 1, the I'ff camera (1) and the ultrasound probe (
The relative positions of the welds (3) and ITV cameras (1) are known and can be controlled.
), it is possible to control its position so that the ultrasonic waves emitted from the ultrasonic probe (2) cover the entire welded part (3).

Iff camera flJ is now checking the welded part (3) of the ERW pipe (4).
Take an image with At this time, in order to emphasize the contrast between the welded part (3) and the portion of the electric resistance welded pipe (4) other than the welded part (3).

Light is irradiated near the welding part (3) using a floodlight.

In this way, the video signal (7) obtained by the ITV camera (11) has a different output level between the welding part (3) and other parts, so the video signal (7) is processed by the signal processing part (6). By taking the differentiation, the entire position of the end of the welding part (3) can be detected from the waveform (8).9 For example, by taking the entire midpoint, the position of the ITV camera (1) with respect to the welding part (3) can be detected.

In this conventional detection device, the entire position of the weld (3) is detected by making full use of the difference in contrast between the slightly raised part of the weld (3) and other parts of the ERW pipe. The position of the weld (3) is detected using all differences in contrast, but the measurement accuracy is not good for items with small contrast, and since the judgment is based on differences in appearance, it is not always possible to identify the true weld. It's hard to say. Production of ERW pipes ξ
In some cases, the welding position detection device can only be installed after the raised part of the welded part (3) is ground with a bead cutter, but in this case, the raised part of the welded part (3)
Since the raised part is eliminated, the contrast with other parts of the electric resistance welded pipe is further reduced, and the position detection accuracy of the welded part (3) is further deteriorated.

The present invention detects the position of the welded part (3) from the temperature distribution of the welded part (3) in order to remove these conventional missing kilns. Embodiments of the present invention will be described below with reference to the drawings.

In Figure 3, (9) is a mirror, α0) (cleanse,
Circle is an infrared detector, (12+ is the highest temperature position detection circuit.

In Figure 3, the infrared rays radiated near the joint 13) are reflected by the mirror (9) and are placed at right angles to the welded part (3) line of the electric resistance welded tube (4) through the entire mirror (10). The light is focused on the detector 0D. The infrared detector 0" outputs an electric signal at a level corresponding to the intensity of the infrared rays emitted from the joint (3), and this is sent to the highest temperature position detection circuit to detect the highest temperature of the infrared pressure detector a. Outputs a position signal in degrees. Figure 4 shows the temperature distribution 03) of surfaces A and B near the welding part (3) shown in Figure 3, and shows the temperature distribution 03) of the infrared detector (11) immediately after welding the two ERW pipes. The outputs are approximately symmetrical left and right with 0 being the maximum output value.

FIG. 5 shows an internal circuit block similar to the maximum temperature position detection circuit, in which the aforementioned infrared detector is placed at aD, and photodiodes for infrared detection form an array from N1 to Ni. (12ri is an analog location multi.

Scanner, (122) is analog 4P capital,
(123 is a gate scanner, (124) is a timing circuit, (125 is a gate circuit, (126)
) is a comparison circuit, (127) is a NIAX register, and (128) is a 1'j output counter circuit.

The infrared signal emitted from the junction (3) input to the infrared detector 0D is an analog multi signal. Scanner (''21)
Unfortunately, the signal of a certain block is completely cut off.

The individual signals outputted are sent to the analog AMP circuit 5 (12
2) is amplified and passed to the gate scanner (123). The gate scanner (124) starts from N2, Nz', N3, etc. according to the instructions of the timing circuit.
The data is used and compared with the previous data and the value of the Δ4AX register (127) in the comparison circuit (126). If the input data is thicker than the data in the MAX register (127), the value of the input data is
7) and at the same time send a count signal to 125J.

The input data value gradually increases as shown in FIG. 4, reaches a peak, and then decreases. In the comparator circuit (12G), if the contents of the MAX register (127) are smaller than the input, no signal is sent to the gate (125) i close 2 capunta (128). Therefore, the position of the peak signal is held in the counter (128). Comparison circuit (126,)
performs the above operation from N1 to Ni. Counter (1
28) Maintain all double peak positions. Counter (128)
is scanned from N1 to N1 of the infrared detector (IIJ), 9 sets are set, and the same operation is repeated for new data input one after another.

As described above, the present invention has the advantage that the ultrasonic deep probe (2) can be positioned at the welding part (3) because the maximum temperature position focus of the electric resistance welded pipe (4), that is, the center point of the welding can be detected.

Furthermore, since the temperature distribution (13) of the welding part (3) changes sharply, the determination accuracy can be improved by optimizing the parameters of the one-position detection device according to the temperature distribution. Further, even after grinding the raised part of the welded part (3) with a bead cutter, the same temperature distribution is maintained, so there is an advantage that similar measurement accuracy can be achieved. Although it is not mentioned here, for the purpose of improving the S ratio,
Mechanical between the lens flO+ and the infrared detector circle
This is a technique often used for choppers (not shown).

Although the above description has been made regarding the case where the pressure is detected at the welding position of the weld, the present invention is not limited to this and may be used for welding of flat plates.

As described above, the present invention has the following advantages: By detecting the maximum temperature position, the position of the true weld (3) can be detected.
2I! It has the effect of improving the I-consistency and also being able to detect the position in the same way even after grinding with a bead cutter.

[Brief explanation of drawings]

Figure 3 shows a 1° view of a conventional welding position detection device. Fig. 2 is a diagram for explaining a conventional detection device, A.3 is a diagram showing an embodiment of the present invention, Fig. 4 is a diagram for explaining a conventional detection device, The figure is a block diagram for explaining the detection device of the present invention. In the figure, (1) is the I'ff camera, (2) is the head of the neck, (3) is the welded part, (4) is the ERW tube, (5) is the floodlight, and (6) is the signal processor. Tension part, (7) θ, video signal, (8
), the damage to the video signal, (9) is ξr!
101cmr lens, aυ is an infrared pressure detector. 02) is a maximum temperature position detection circuit. O is the maximum temperature position, and A and B are located on the surface of the electric resistance welded tube on opposite sides of the maximum temperature position O. In FIG. 2, the same or similar foil portions are designated by the same reference numerals. Agent Hitoiwamasu, Yu 14th 2nd FgJ 3rd Figure Section 4 Figure AOB 5th Cause

Claims (1)

[Claims] In a welding position detection device for electric resistance welded pipes, etc., there is a reflecting mirror that changes the direction of infrared rays emitted from a surface area near the welding part, a lens system that completely focuses the infrared rays reflected by this mirror, and this lens system. The molten metal temperature detection circuit consists of an infrared detector that receives the infrared rays that have passed through the weld, and a maximum hot metal temperature position detection circuit that detects the highest hot metal temperature position on the surface of the welded part (based on the output signal of this detector). Welding position detection device.