JPS6010835B2 - A device for detecting the cross-sectional shape of the inner weld of a welded pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting the cross-sectional shape of an inner welded portion of a welded pipe such as an electric resistance welded steel pipe.

For example, to make a welded steel pipe, a sheet material is continuously moved forward and shaped into a tubular shape, and a squeeze roll applies a predetermined pressure to the tubular material, while a contact tip is applied to the material before the squeeze roll. , by supplying high-frequency current from a high-frequency oscillator to the materials, thus heating and pressurizing the abutting portions of the materials to weld.

As shown in Figure 1, a bead 1 caused by military stitch welding
are raised on the inner and outer surfaces of the tube body 2, respectively. Both the inner and outer surfaces of such a bead 1 are scraped off by the outside of the bead cutter, but if the shape is not favorable,
After bead removal, metal with a composition different from that of the base metal may remain in the welded part of the pipe body, or the welding may be incomplete, resulting in the manufacture of defective welded pipes. . On the other hand, as shown in FIG. 2, the raised portion IA of the pea 1 on the inner surface of the tubular body 2 is cut off by the cutter 3. (The cutter 3 is attached to a mandrel bar 4 whose axis line is aligned with the Sakaki line of the tube body 2.) However, if the cutting by the cutter 3 is normal, the inner surface of the tube body 2 and It is formed on the same surface as the surface of the bead cutting part without any unevenness.
However, if the cutting by the cutter 3 is not normal, the bead raised portion IA will protrude or become depressed, as shown in FIGS. 3 and 4. Therefore, it is an extremely important issue in the manufacture of electric resistance welded pipes to accurately determine the quality of the welded part shape as quickly as possible before such pipes with internal bead cutting defects are produced in large quantities.

However, conventionally, the quality of the shape of the inner welded part of a welded pipe, such as a welded pipe, has been judged by visually observing the inner surface of the pipe that has been cut into a predetermined length after welding. It has been difficult to accurately and quickly detect (judge) the cross-sectional shape of the internal weld.

Therefore, this invention applies a photosection method to
We provide a device that can accurately detect the cross-sectional shape of the inner welded part of Tawara-ko pipe in real time. a slit light projecting means and a light receiving means, which are substantially parallel to the slit light projecting means, and a light projecting refracting means for refracting the slit light from the light projecting means to irradiate the inner welded part of the welded tube. a light-receiving refracting means for refracting the reflected light of the slit light irradiated onto the inner welded portion and making it enter the light-receiving means; and a welded portion of the welded pipe based on light reception information from the light-receiving means. The present invention is characterized in that it includes a detection means for detecting a cross-sectional shape.

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

FIG. 5 is an explanatory diagram of a cross-sectional shape detection device for an inner welded portion of an open-seamed steel pipe according to the present invention.

The mandrel bar 4 has a casing 5 before and after the cutter 3.
is attached, and a cylindrical lens 6 as a light projecting means for converting spot light into slit light and an ITV camera 7 as a light receiving means are fixedly installed in the casing 5. Lens 6 and I
The TV camera 7 and the TV camera 7 are close to each other, their optical axes are substantially parallel to each other, and both optical axes are substantially parallel to the tube axis of the tube body 2 . Therefore, the cylindrical lens 6 and I
The TV camera 7 can be brought as close as physically possible and is arranged between the mandrel bar 4 and the inner surface of the tube body 2. At the top of the casing 5, there is an opening □5.
a is formed, and the slit light from the cylindrical lens 6 passes through mirrors 8 and 9 fixed in the casing 5.
and through the opening 5a, the test area A (the raised portion IA of the bead) and the test area B on the inner surface of the tube body 2.
(the welded part after bead cutting) is irradiated along the pipe circumference. The reflected light from the test parts A and B passes through the opening □ 5a and passes through the mirror 1 fixed to the casing 5 inside the casing 5.
0 and illuminates the ITV 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, and 12 is a cable for taking out a signal from the ITV camera 7. and this cable 1
2 is input to, for example, a CRT (cathode ray tube, not shown). 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 directed toward the object to be examined. A, B
It is irradiated along the control station.

The slit light irradiated on the test parts A and B detects the raised part IA of the bead which passes through as the tube body 2 moves.
Reflected light A' corresponding to the profile of (see Figure 6 A)
, and reflected light B' corresponding to the profile of the welded part after cutting (see the opening in FIG. 6) are obtained, and this reflected light is refracted by the mirror 10' and incident on the ITV camera 7. In this way, the shape detection signal corresponding to the profile of the raised portion IA and the welded part after cutting, obtained by the ITV camera 7, is input to the CRT, where an accurate shape corresponding to the profile is obtained. Welding conditions (heat input, squeeze amount, etc.) in real time based on
Also, the cutting status of the cutter is managed. In addition, instead of the ITV camera 7, an optical lens (in this case, it is sufficient to guide the image from its imaging point to an external bran imaging device using an image fiber, and by doing this, it is possible to avoid tortoise stitching when using the ITV camera. prisms can be used instead of mirrors (which avoids the problem of induction interference of high frequencies for welding).

Alternatively, the cross-sectional shape of the inner welded portion of only one of the front and rear sides of the cutter 3 may be detected. As explained above, in the present invention, the cross-sectional shape of the inner welded portion of the welded pipe can be accurately detected in real time.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of the cross-sectional shape of a welded part of a hexagonal welded pipe, Fig. 2 is a diagram showing the cutting mode of the same inner welded part, and Figs. 3 and 4 are diagrams showing the cutting shape of the same inner welded part. Figure 5 showing an example
The figure is an explanatory diagram of a cross-sectional shape detection device for an inner welded part of a threaded steel pipe according to the present invention, and FIG. 6A is a diagram showing an example of reflected light. 6...Cylindrical lens, 7...ITV camera, 8
, 9, 10... Mihu-. Figure 2 Hakama Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1 are close to each other and their optical axes are substantially parallel;
and a slit light projecting means and a light receiving means, the optical axis of which is substantially parallel to the tube axis of the welded pipe, and for refracting the slit light from the light projecting means to irradiate the inner welded part of the welded pipe. a light projecting refracting means, a light receiving refracting means for refracting the reflected light of the slit light irradiated on the inner surface welding part and making it enter the light receiving means, and a light receiving means based on the light reception information from the light receiving means. A detection device for detecting a cross-sectional shape of an inner welded portion of a welded pipe, comprising a detection means for detecting a cross-sectional shape of a welded portion of the welded pipe.