JPH05240844A - Copying method of flaw detecting apparatus for welded part of seam welded pipe - Google Patents

Abstract

PURPOSE:To move a probe for copying accurately and automatically with respect to a welded part by measuring the outer shape and the bending of a pipe, and correcting the copied amount in response to the amount of deviation from a preset value. CONSTITUTION:When a seam welded pipe 2 advances to the side of a probe holder 4 and reaches the position of a TV camera 6, the camera 6 starts the measurement and the correcting computation of the amount of deviation between the position of a strip and a reference position. At the same time when a strip measuring signal is corrected with the shape of a pipe (external shape, bending and the like), shape of the pipe is measured with and the position of the strip is geometrically corrected based on the shape. After the correction, an operating device 8 converts the position into the position of the welded part. The result is continuously stored as the amount of the copying movement of the probe with a copy control part 9. When the welded part 1 of the front end part of the seam welded pipe 2 reaches the part directly beneath the holder 4, the device 9 transfers the amount of copying movement corresponding to the amount of the deviation of the welded part 1 to a copying mechanism 4', continuously controls the copying movement of the probe with the advancing movement of the seam welded pipe 2 and makes the position relationship between the welded part 1 and the holder 4 always constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for accurately moving a flaw detection device for an electric resistance welded pipe to a position of the weld.

[0002]

2. Description of the Related Art As a quality inspection of an electric resistance welded pipe, generally, a water pressure test and an ultrasonic flaw detection for conducting a quality inspection of a welded part (seam) after the water pressure test are carried out are adopted.
In the flaw detection device that performs this ultrasonic flaw detection, it is necessary to maintain a constant positional relationship between the welded portion and the position where the ultrasonic wave is incident. However, in the electric resistance welded steel pipe, since the material change between the welded portion and the base metal portion disappears after the heat treatment, in the flaw detection method using ultrasonic waves, radiation or electromagnetic induction,
It is extremely difficult to detect welds.

Therefore, conventionally, prior to ultrasonic flaw detection, an operator was always present near the flaw detector, visually detecting the welded portion, and manually adjusting the ultrasonic wave incident position. Further, Japanese Utility Model Application Laid-Open No. 54-131744 proposes a method of optically observing and detecting the position of a welded portion formed on the inner surface of an electric resistance welded pipe and copying it. ◎
However, the former method has problems such as an increased load on the operator and a decrease in flaw detection accuracy due to an operation error. In the latter method, the inner surface of the heat-treated electric resistance welded pipe has a small difference in brightness between the bead cutting surface and the base metal portion, which makes optical detection difficult. Also, the bead cutting surface has a width of about 5 to 20 mm, and thus welding. There was a problem such as poor detection accuracy of part position.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art in flaw detection of a welded portion of an electric resistance welded pipe, and allows the flaw detection device to automatically and accurately follow the welded portion. It is intended to provide a method that enables the above.

[0005]

To achieve the above object, the present invention is directed to a flaw detection device for flaw detection of a welded portion of an electric resistance welded pipe in an axial transfer line of the electric resistance welded pipe. While moving forward, by an observing device installed adjacent to the conveying line, optically observe a strip line continuously marked in the axial direction at a constant position in the circumferential direction from the welded portion of the electric resistance welded pipe, A deviation amount between the observation position of the band-shaped line and a predetermined position is calculated, and the flaw detection device or the electric resistance welded pipe is imitated by a copying amount according to the deviation amount, and a welded portion between the flaw detection device and the electric resistance welded pipe. In the copying method for always maintaining a constant positional relationship, the pipe shape measuring device continuously measures the outer diameter and bend of the electric resistance welded pipe and determines the copying amount according to the amount of deviation from their planned values. It is characterized by correcting.

A method of continuously marking a band-shaped line in a circumferential direction at a fixed position in the circumferential direction from a welded portion of an electric resistance welded pipe is as follows: After welding on a pipe forming line of the electric resistance welded pipe (for example, after bead cutting on the inner and outer surfaces). ), Marking equipment may be installed on the outer surface of the electric resistance welded pipe at a predetermined position (for example, a position inclined by 80 degrees) from the welded portion. After the welding of the pipe making line, since the welded portion is constrained at a fixed position, it is possible to accurately mark the predetermined position. Further, it is desirable to measure the shape of the pipe continuously in the longitudinal direction of the pipe between the hydraulic test and the flaw detection of the welded portion. This is because the shape of the pipe (outer diameter, bend, roundness, etc.) changes when water pressure is applied.

Hereinafter, an embodiment in which the present invention is applied to ultrasonic flaw detection of an electric resistance welded pipe will be described in detail with reference to the drawings of FIG.

As shown in FIG. 1, an electric resistance welded pipe 2 having a welded portion 1 substantially parallel to the central axis formed over the entire length of the pipe is carried into the chain conveyor 3 from the right by a carry-in device (not shown) to a predetermined position. Is positioned at the position. A probe holder 4 of an ultrasonic flaw detector is installed above the welded portion 1 at the rear of the position of the electric resistance welded pipe 2 in the conveying direction. At a position adjacent to the transfer line, a television camera 6 for observing the position of the strip line 5 continuously marked in the pipe axis direction is installed at a fixed position in the circumferential direction from the welded portion 1 of the electric resistance welded pipe 2. ing.
The shape of the pipe (outer diameter, bend, roundness, etc.)
A pipe shape measuring machine (not shown) for measuring The probe holder 4 provided with a probe for detecting a welding defect in the welded portion 1 is opposed to the outer peripheral surface of the electric resistance welded pipe 2 which is moved forward by the operation of the chain conveyor, and the base end portion thereof is a pedestal (not shown). No. 1) is supported by the tip of a copying mechanism 4'which is movably mounted in the radial direction and the circumferential direction of the electric resistance welded pipe 2.

The television camera 6 is positioned with respect to various pipe outer diameters such that the line connecting the center of the pipe and the camera is always at a constant angle (for example, 80 °) with the vertical direction in a cross section perpendicular to the conveying line. The image signal from the television camera 6 is processed in the television camera 6 by using the position of the strip line 5 as a coordinate having the position where the strip line 5 should be as a coordinate origin in advance, and an actual welding process. The coordinates of the part 1 are corrected by the pipe shape (outer diameter, bend, roundness, etc.) signal from the pipe shape (outer diameter, bend, roundness, etc.) signal from the measuring instrument, and the deviation from the coordinate origin is exceeded. An arithmetic processing unit 8 for converting the scanning movement amount of the probe holder 4 of the ultrasonic flaw detector and a control unit 9 for receiving a signal from the arithmetic processing unit 8 and regulating the copying operation of the ultrasonic flaw detector are connected. ing.

Next, the operating condition of this apparatus will be described with reference to FIGS. The electric resistance welded pipe 2 is transferred onto the chain conveyor 3 by the transfer device, and the chain conveyor operates to move the electric resistance welded pipe 2 toward the probe holder 4 side at a constant speed. When the electric resistance welded pipe 2 reaches the position of the television camera 6, the television camera 6
Starts measurement and correction calculation of the amount of deviation of the band 5 position from the reference position. At the same time, when the strip line measurement signal is corrected based on the bending of the tube shape, for example, from two different directions as shown in FIGS. 2 and 3 in the cross section orthogonal to the transport line at the same position as the television camera 6. Distance meters 16 and 17 for measuring the distance to the pipe are installed, and Δh and Δ of the difference between the detection reference position and the position of the pipe due to bending of the pipe.
In the case of left and right bends in FIG. 2 by measuring l and performing geometrical calculation, assuming that the pipe radius is r and the misrecognition angle is Δα.

[Equation 1] In the case of misidentification of the strip line positions 10 and 11, and in the case of vertical bending in FIG. 3,

[Equation 2] Correct the misidentification between the strip line positions 10 and 11.

When the outer diameter and the roundness are also corrected, for example, a pipe shape measuring device as shown in FIG. 4 is installed at the same position as the television camera 6 in a cross section orthogonal to the conveying line. The pipe shape measuring device has a projector 19 and a light receiver 20 which are rotated on a rotary plate 18 and which are rotated perpendicularly to a transport line, and which continuously project projected views of the pipe while rotating in the circumferential direction of the pipe. By obtaining it, it becomes possible to measure the pipe shape (outer diameter, bend, roundness, etc.) (D = L-
(A + B)). After the geometrical correction of the band-shaped line position from the shape similarly to the above-described bending correction, the position of the welded portion is converted through the arithmetic processing unit 8 and is continuously copied as the copying movement amount of the probe. It will be remembered in 9. When the welded portion 1 at the front end portion of the electric resistance welded pipe 2 reaches directly below the probe holder 4, the scanning movement amount corresponding to the amount of deviation of the welded portion 1 from the coordinate origin is ultrasonically detected by the scanning control device 9. The probe is continuously transmitted to the copying mechanism 4'of the device so that the positional relationship between the welded portion 1 and the probe holder 4 is always constant with the forward movement of the electric resistance welded pipe 2. Will be controlled.

[0012]

As described above, according to the copying method of the flaw detection apparatus of the present invention, the shape of the pipe (outer diameter, bend, roundness, etc.) is continuously measured, the band line position is corrected, and this is corrected in advance. Since the scanning movement of the flaw detection device is controlled by detecting and storing it as a deviation from the set position, the flaw detection device can be accurately and automatically moved along the welded portion of the electric resistance welded pipe. It has become possible. Therefore, the quality of the welded portion of the electric resistance welded pipe can be surely guaranteed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a flaw detection apparatus of the present invention.

FIG. 2 is an explanatory diagram of a tube bend correction.

FIG. 3 is an explanatory diagram of a tube bend correction.

FIG. 4 is an explanatory view of an apparatus for measuring a pipe shape.

[Explanation of symbols]

 1 Welded part 2 ERW pipe 3 Chain conveyor 4 Probe holder 4 'Copying mechanism 5 Strip line 6 Television camera 7 Image processing device 8 Arithmetic processing device 9 Copying control device 10 Strip line position when there is no bend 11 There is a bend Band-shaped position when misrecognized position 12 Pipe position when there is a bend 13 Pipe position when there is no bend 14 Welded portion 15 Television camera 16 Distance meter 17 Distance meter 18 Rotating plate 19 Emitter 20 Light receiver

Claims (1)

[Claims] 1. An observation device installed adjacent to a transfer line while advancing the electric resistance welded pipe toward an inspection device for detecting a welded portion of the electric resistance welded pipe in an axial transfer line. By the optical observation of the belt-shaped line continuously marked in the axial direction at a constant position in the circumferential direction from the welded portion of the electric resistance welded pipe, the deviation between the observed position of the belt-shaped line and the predetermined position In the copying method of calculating the amount, copying the flaw detection device or the electric resistance welded pipe with a copying amount according to the deviation amount, and always maintaining a fixed positional relationship between the flaw detection device and the welded portion of the electric resistance welded pipe, Electric resistance welding characterized in that the measured values of the outer diameter, bending and roundness of the electric resistance welded pipe measured by a shape measuring device are used to correct the copying amount in accordance with the deviation amount from the planned values. Copying method for pipe weld inspection equipment.