JPS601138B2 - How to determine the cutting status of the inner bead of an ERW welded pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining on-line (in real time) the cutting status of a bead cut portion immediately after cutting an inner weld bead during the manufacture of a welded welded pipe.

In the production of exposed welded pipes, the bead cutting status of the inner weld was conventionally determined by visually inspecting the end face of the product cut to a predetermined size online, but this method
This method was extremely inefficient, and there was a risk of producing a large number of defective products.

Therefore, as a method for measuring the cut shape of a pipe inner bead on-line, a method described in Tokkoku-Kekki No. 54-21372 has been proposed.

This method uses an ultrasonic thickness meter to extract the pipe thickness signal of the inner bead cut portion and measure the cut shape of the inner bead of the pipe, but it has the drawback of poor detection accuracy. Therefore, this invention was made in consideration of the above-mentioned problems, and it is possible to irradiate a slit light onto the inner welded part of the moving raw pipe after bead cutting, and to cut the light cut obtained at the inner welded part. The profile is imaged by an optical image receiving means, a shape measurement signal of the inner welded part obtained by the optical image receiving means is compared with a reference inner surface shape signal of the Qin tube, and based on the comparison result thus obtained, The present invention is characterized in that it is a method for determining the cutting condition of an inner bead of a lightning-stitched welded pipe, in which the cutting condition of the bead of the inner welded portion is determined.

The present invention will be explained below by way of examples with reference to the drawings.

FIG. 1 is an explanatory diagram of a device for detecting the cutting shape of an inner bead of a lightning-stitch welded steel pipe for carrying out the present invention.

Reference numeral 1 denotes a raw pipe welded with a thread stitch, 2 a squeeze roll, 3 a cutter for cutting the inner bead of the raw pipe 1, and 4 a mandrel bar to which the cutter 3 is fixed.

A casing 5 is attached to the mandrel bar 4 after the cutter 3, and inside the casing 5 is a light projecting means for converting a spot light from a laser light generator into a slit light as described later. Cylindrical lens 6
and an ITV camera 7 as a light receiving means are fixedly installed, and the cylindrical lens 6 and ITV camera 7 are
They are close to each other, their optical axes are substantially parallel, and both optical axes are substantially parallel to the tube axis of the blank tube 2. Therefore, the cylindrical lens 6 and the ITV camera 7 are
It can be brought as close as physically possible, and is arranged between the mandle lever 4 and the inner surface of the raw pipe 1. An opening 5a is formed in the upper part of the casing 5, and the slit light from the cylindrical lens 6 is refracted by mirrors 8 and 9 fixed within the casing 5.
Through the opening 5a, the beam is irradiated along the tube circumference onto the welded portion of the inner surface of the raw tube 2 after bead cutting, and a light cutting profile is formed there. Thus formed on the inner surface weld,
The reflected light of the light cutting profile corresponding to the inner cross-sectional shape passes through the Sekiguchi 5a, is refracted inside the casing 5 by the mirror 1 fixed to the casing 5, and is refracted by the mirror 1 fixed to the casing 5.
The light is incident on the V camera 7. Note that 11 is an optical fiber for guiding a laser beam as a spot light from a laser light generator (not shown) to the cylindrical lens 6;
12 is a cable for taking out a signal from the ITV camera 7, and this cable 12 is input to a CRT (cathode ray tube, not shown) which will be described later. Therefore, with the above configuration, the laser light generated by the laser light generator passes through the optical fiber 11, is projected as a slit light from the cylindrical lens 6, is refracted by the mirrors 8 and 9, and is reflected in the welded part after bead cutting. The slit light is irradiated along the circumference of the pipe, and reflected light corresponding to the profile of the welded part after bead cutting, which passes through this as the raw pipe 1 moves, is obtained, and this reflected light is It is refracted by the mirror 10 and enters the ITV camera 7.

In this way, the shape image signal corresponding to the profile of the welded part after tobead cutting obtained by the ITV camera 7 is "
The image is input to the CRT and an accurate shape image corresponding to the profile is obtained. FIG. 2 is a block diagram of an inner bead cutting state determination device for carrying out the present invention.

In the figure, 13 is a CRT, 14 is an (image) analysis device, 15 is a calculation unit, 16 is an analysis device 14 and a calculation unit 15.
This is a recorder consisting of an XY recorder etc. connected to the Third
Figures a, a' to e, and e' show cross sections (a to e) of the inner welded part of the raw pipe 2 immediately after cutting the inner bead, and the CR at that time.
Examples of images (a' to e') of T13 are shown. Figure 3 a, a
' is when the raised part of the bead remains as an uncut part 31, Figure 3 b and b' are normal, Figure 3 c and c' are when over-cut part 32 is formed, and Figure 3 d, d' cutter 3
When the cutter 3 is damaged and a defective shape portion 33 is formed, FIGS. Just by showing the image, the shape of the peed cutting immediately after cutting the welded part can be monitored online, and the angle between the tube axis of the base pipe 2 and the slit light irradiated on the welded part (light cutting angle)
By optimizing (that is, as this approaches 450, a light cutting profile that almost corresponds to the actual cross-sectional shape is formed, and as this approaches 00, the unevenness is emphasized, in other words, the profile is expanded in the tube axis direction. It is also possible to monitor irregularities of 0.1 Yanagi or less (measured). Next, an example of a method using the analysis device 14 and the computing unit 15 to determine the internal bead cutting status from the received shape signal of the internal welded portion obtained by the ITV camera 6 will be described.

That is, the shape image reception signal from the ITV camera 7 is transmitted to the CRT1.
3, and is further input to the analysis device 14, where it is analyzed and converted into one-dimensional information convenient for calculation (for example, as shown in FIG. Then, by sampling along the x-axis and detecting the maximum brightness (intensity) coordinate on the sampling line parallel to the Y-axis, the two-dimensional shape received signal will be converted to one-dimensional information. On the other hand, by giving the inner diameter of the Qin tube 2 and the light cutting angle, the calculator 15 can obtain a one-dimensional shape measurement signal corresponding to the reference inner surface (inner surface of the raw tube 2). Arithmetic formula yAi=f(xi)
・・・・・・【11 can be given.

The arithmetic unit 15 uses equation '11 and the shape measurement signal yl=g(x
i) ……'2), i.e. yi-yAi=g(xi)-f(xi)
...By calculating {3', it is possible to determine the bead cutting status of the inner welded part of the pipe 2, so based on this determination result, the position of the mandrel bar 4 is controlled, the cutter 3 is replaced, etc. All you have to do is

That is, for example, in the case of FIG.
Since i<0, therefore, when this calculation result is applied to the recorder 16 (XY recorder), the result is as shown in FIG. 4a.

In this case, the amount of cutting may be increased by an amount corresponding to Δt. The allowable range is between the two parallel dotted lines in the figure (the same applies below). Similarly, the calculation results of FIG. 3 b, b' to e, e' using the {3l formula are as shown in FIG. 4 b to e. In the cases shown in FIGS. 3b and 3b', as shown in FIG. 4b, it is within the permissible range and the current situation should be maintained. In the case of Figure 3 c, c', Figure 4 c
As shown in , it is sufficient to reduce the amount of cutting by an amount corresponding to Δt. In the case of Fig. 3 d and d', as shown in Fig. 4 d, reduce the cutting amount by the corresponding amount of △t on the D side, and increase the cutting amount by the corresponding amount of △tF on the F side. good. In the cases shown in FIG. 3e and e', as shown in FIG. 4e, the recording line is within the allowable range, but since the recorded line is wavy, a warning is issued indicating that the bead cutter is missing, and the cutter is replaced. As described above, in the present invention, the cutting condition of the bead cut portion immediately after cutting the inner weld bead can be determined online, which can contribute to the manufacture of an appropriate exposed welded pipe.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a device for detecting the cut shape of an inner bead of a welded steel pipe for implementing the present invention, and FIG. 2 is a configuration diagram of a device for determining the cutting state of an inner bead for implementing the present invention.
Figures 3a to 3e are diagrams showing a cross section of the inner welded part of the raw pipe immediately after inner surface welding, Figures 3a' to e are diagrams showing CRT images showing the cross-sectional shape of the inner welded part, and Figure 4. a to e are diagrams showing the calculation results in the cases of a, a' to e, and e' in FIG. 3, respectively. 1... Plain pipe, 2... Squeeze roll,
3... ... Katsuta, 4... Mandrel bar, 5...
Casing, 6... Cylindrical lens, 7...
ITV camera, 8, 9, 10... Mifu, 11... Optical fiber, 12... Cable, 13... CRT
, 14...-Analysis device, 15... Arithmetic unit, 1
6...Recorder. Diamond diagram Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. After bead cutting, slit light is irradiated onto the inner welded part of the moving blank pipe, and the optical cutting profile obtained on the inner welded part is imaged by an optical image receiving means. A shape measurement signal of the inner welded portion is compared with a reference inner surface shape signal of the blank pipe, and a bead cutting condition of the inner welded portion is determined based on the comparison result thus obtained. Method for determining the cutting status of the inner bead of a sewn welded pipe.