JP2008175577A - Method and device for monitoring welded part of electro-resistance-welded pipe and manufacturing method of electro-resistance-welded pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a monitor device capable of confirming the circumferential profile of a pipe inner surface and the image of the surface of the bead cut part of the pipe inner surface on the same monitor screen by device arrangement using a small-sized laser oscillator or imaging device. <P>SOLUTION: In a monitor method of the welded part of the electro-resistance-welded pipe, the surface of the inner surface welded part of the electro-resistance-welded pipe is irradiated with a laser beam or scanned by the laser beam; the obtained reflected beam is imaged by the imaging device and the circumferential profile of the pipe inner surface and the image of the surface of the bead cut part of the pipe inner surface are displayed on the same monitor screen. The monitor device of the welded part of the electro-resistance-welded pipe is equipped with the laser oscillator, a laser reflecting plate, a prism, the imaging device, a temperature regulator and the monitor screen. Further, a cutting and welding condition is controlled on the basis of monitor display data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for monitoring the cutting shape of a pipe inner surface bead during the production of an electric resistance welded pipe.

  When welding an ERW welded pipe, the bead of the ERW generated on the inner and outer surfaces of the pipe by pressure welding is higher than the thickness of the ERW welded pipe, and the shape of this bead is related to the weld strength of the product. Therefore, it is usually removed by a bite immediately after ERW welding.

  Therefore, when cutting the bead of the electric seam welded portion, it is necessary to constantly monitor whether the cutting is properly performed, such as lack of thickness due to excessive cutting or leaving behind. In the case of visual inspection, it is common to visually inspect the shape of the inner and outer surfaces of the steel pipe with a cooling bed after being cut into product length after pipe making. There is a problem that a large number of defective products are generated when it is far away, and when an abnormality in pipe making is noticed by visual inspection.

  Therefore, various methods for constantly monitoring the cutting state of the inner surface bead of the ERW weld pipe, which is difficult to visually observe, have been studied. As for the conventional invention relating to the method and apparatus for detecting the welded pipe bead, an optical method, a mechanical method, an ultrasonic method, and the like have been proposed.

  As an optical method, Japanese Patent Application Laid-Open No. H10-228667 identifies the image by picking up an image of the pipe surface, extracting signal waveform feature values unique to the welded part and the base metal part, and encoding them with feature values stored in advance. A method has been proposed.

  As a mechanical method, Patent Document 2 detects the cutting shape of the inner surface bead by changing the position in the height direction while skewing the inner surface bead cutting portion with the detection roller being centered on the weld line. A method has been proposed.

As a method using ultrasonic waves, in Patent Document 3, ultrasonic waves are transmitted from the outer surface side of the ERW pipe to the welded portion at a predetermined scanning pitch, and the outer surface reflected wave and the inner surface reflected wave of the welded portion are received. The timer circuit measures the time difference between the detection timing of the external reflection wave and the detection timing of the internal reflection wave. Next, a method has been proposed in which the amount of protrusion of the inner bead is calculated by an arithmetic circuit based on the data stored in the memory circuit.
Japanese Examined Patent Publication No. 7-117495 Japanese Patent No. 2683066 JP-A 61-273273

  However, the optical method of Patent Document 1 is a method for detecting a difference in luminance between the bead portion and the base material portion. However, the luminance of the bead portion greatly depends on the welding conditions and the wall thickness of the pipe, and thus is stable. If the bead portion is difficult to detect and the bead portion has low brightness, there is a problem that the bead portion cannot be identified.

  In the mechanical method of Patent Document 2, there is a problem that a sensor having a drive system is severely worn by a roller or mechanically damaged in an environment where high temperature, high humidity, spatter, and steam exist.

  In addition, in the method using ultrasonic waves of Patent Document 3, it is necessary to pour cooling water in order to protect the ultrasonic transmission device in order to travel through the high temperature portion of the pipe. There is a problem that it is necessary to align the outer diameter unit of the pipe and the shoe of the probe.

  The present invention has been made to solve the above-mentioned problems of the prior art, and as a measurement technique, the optical cutting method and the dynamic method can be used as a measuring technique by the equipment arrangement using the small laser oscillation device and the imaging device shown in FIG. This is an electro-welded welded pipe monitoring method and monitoring device that can confirm the circumferential profile of the inner surface of the pipe and the image of the surface of the bead cutting part of the inner surface of the pipe on the same monitor screen using an image processing technique that applies moment calculation. This is a method for manufacturing an electric resistance welded pipe that controls cutting conditions and welding conditions based on information displayed on a monitor screen by a special means.

  (1) The first invention irradiates or scans the inner surface of the welded portion of the ERW welded tube with a laser, images the obtained reflected light with an imaging device, and the circumferential profile of the inner surface of the tube and the inner bead of the inner tube. An electric resistance welded pipe welding monitoring method characterized in that an image of a surface of a cutting part is displayed on the same monitor screen.

  (2) The second invention is characterized in that the pressing force of the bead cutting bite and the pressing force of the pipe making roll are controlled based on the circumferential profile of the pipe inner surface and the image of the surface of the bead cutting part of the pipe inner surface. It is a manufacturing method of an electric resistance welded pipe.

  (3) A third aspect of the invention is an optical detection means for housing a laser oscillator, a laser reflector, a prism, and an imaging device attached to a holder of an ERW weld bead cutting tool, and measuring the temperature in the optical detection means. An electro-welded pipe welding monitoring apparatus comprising: a temperature adjusting means for cooling; and a monitor means for displaying an image captured by the imaging device on a monitor screen.

  Here, the circumferential profile of the inner surface of the pipe refers to the shape of the inner surface of the ERW weld pipe in the circumferential direction.

  According to the present invention, it is possible to monitor the shape required for on-line cutting shape management of the ERW pipe on-line, so that the pipe inner surface cutting condition and further the welding condition can be adjusted in real time.

FIG. 1 shows an apparatus configuration of the present invention. The target mother pipe is a small diameter ERW steel pipe of φ88 mm.
The laser oscillator 1 can be rotated vertically and horizontally so that the laser irradiation direction can be changed according to the inner diameter of the tube. The laser beam is reflected by the laser reflecting plate 2, passes through the window 6, and is applied to the bead portion 9. The laser reflector 2 is also rotatable so that the reflected laser light can be accurately irradiated onto the bead portion 9.

  The window 6 is a window opened in the case 5 so that the bead portion is irradiated with the laser beam. The reflected light from the bead portion is condensed and refracted by the prism 3 and received by the imaging device 4. As the imaging device 4, a small CCD camera or the like can be used. A signal from the imaging device 4 is connected to the monitor device by a cable attached to the cutting tool holder 10.

Each device described above is housed in the case 5 and fixed to the cutting tool holder 10.
The case 5 may be made of SUS material or the like as long as it is dustproof, heat resistant and durable. In addition, since the temperature inside the case 5 is over 120 degrees, and there is a risk of damaging the sensors, if the temperature is measured with a thermocouple and the internal temperature exceeds 30 ° C, liquid nitrogen is allowed to flow through the fluorine resin piping. Thus, the inside of the case 5 can be cooled.

  A protective mirror is attached to the surface of the prism 3 facing the window 6 to prevent the laser beam from being attenuated by preventing damage to the prism and preventing dust.

  Fig. 2 shows the inner surface profile of an ERW welded tube measured by laser irradiation. Fig. 2 (a) shows an example in which bead cutting is performed properly with a normal material, and the profile on the inner surface of the tube has an arc shape. You can see that FIG. 2B shows an example in which the bead portion is deeply cut in the thickness direction, and the profile has a shape in which two circular arcs are stacked. FIG. 2 (c) shows an example in which the bead portion is shallowly cut and the bead remains, contrary to FIG. 2 (b).

  The screens of FIGS. 3B and 3D are obtained by displaying the tube inner surface profile by laser irradiation and the cutting state of the tube inner surface by a camera image on the same monitor screen. In the prior art (the screens shown in FIGS. 3 (a) and 3 (c)), when the pipe inner surface profile is displayed, an image showing the surface state of the cutting surface cannot be displayed. As shown in FIGS. 3B and 3D, the inner surface profile of the tube and the image of the inner surface of the tube can be displayed on the same monitor screen.

  In the screens shown in FIGS. 3A and 3C, it is possible to recognize the difference in the tube inner surface shape (tube inner surface profile) as shown in FIG. It is impossible to find a difference. On the other hand, in FIG. 3B and FIG. 3D, the difference to be identified can be recognized based on the difference in light and dark of the image.

The reason for making these possible is the following (1) and (2).
(1) In a portion where the tube surface is smooth and close to a mirror surface, such as a bead cutting portion, most of the light is regularly reflected, and the amount of light reflected in the photographing direction is small. On the other hand, the uncut portion (streaks remaining) generation portion remains almost the original rough surface (uncut surface), so that the directivity of the reflected light is further spread and a considerable amount of light returns in the photographing direction. From this difference in the amount of light, it is possible to distinguish between a bead cutting portion and a base material (uncut portion) or occurrence of uncut portions (streaks remaining).

  (2) The presence or absence of streaks can be identified by capturing a bright area in the monitor screen other than the slit light. In order to obtain these, it was possible with appropriate camera settings (lens selection, aperture setting, etc.).

  In the screen of FIG. 3 (b), since the cutting position and the bead axis are shifted, a normal arc cannot be obtained, and the shoulder portion and the uncut portion remain. In the screen of FIG. 3D, the profile of the inner surface of the tube has a shape close to a circular arc, but the uncut portion remains as a streak remaining. The “streaks remaining” is a cutting defect called chipping, in which the cutting edge of the cutting tool is not appropriate, an uncut portion remains, and it looks like a streak. This defect cannot be detected by the tube inner surface profile.

  Therefore, as shown in FIG. 3B and FIG. 3D, the pipe inner surface profile and the camera image are displayed on the same monitor screen, and “depth” is an item for managing the inner surface of the pipe when manufacturing an electric resistance welded pipe. “Shaving”, “Striping”, “Bead remaining”, “Leave streaks” can be managed on one monitor screen, so feedback to the upper process (bead cutting process, welding process) when a defect or abnormality occurs is quick Came to be made.

  Here, “deep cutting” refers to a cutting defect in which the pressing force of the cutting tool is too strong and the bead portion is cut deeper than the specified cutting amount. This means that the thickness of the ERW welded pipe is locally reduced, so that the pressing force of the cutting tool needs to be adjusted.

  The “single cut” is a cutting defect in which the entire bead width is not cut and only one side is cut. When this defect occurs, the directionality and setting position of the cutting bit with respect to the tube axis are corrected, or when the cutting bit alone cannot be corrected, it is also necessary to correct the twist of the tube in the welding process.

  The “bead residue” means a cutting defect in which the cutting bite is weak, the cutting depth is shallow, and the crest of the bead is not removed. The “streaks remaining” is as described above.

  When the generated defect occurs, the bead cutting is corrected by adjusting the cutting tool, adjusting the roll, or the like.

  An example is shown in FIG. FIG. 4A is a monitor screen in the case where the position of the inner surface bead is shifted from the position of the inner surface cutting bite due to the rolling of the electroformed welded pipe, and the one side of the bead cutting occurs.

  In such a case, adjusting the pressing force and roll position of the ERW welded pipe making roll to eliminate rolling, and to match the position of the inner surface bead and the position of the inner surface cutting tool, FIG. The monitor screen shown is obtained. In this way, the cutting state of the pipe inner surface by the pipe inner surface profile and the camera image can be displayed on the same monitor screen, so the cause of the bead cutting defect can be judged online in a short time, so the pipe making method can be adjusted. It can be done quickly.

  INDUSTRIAL APPLICABILITY According to the present invention, the present invention can be applied to a field where it is necessary to confirm a situation inside a product that cannot be visually observed from the outside.

It is a figure explaining the apparatus structure of this invention. It is a figure explaining the measurement result of a pipe inner surface profile. It is a figure explaining the cutting state of a pipe inner surface profile and a pipe inner surface. It is drawing explaining the adjustment example of a pipe making method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser oscillator 2 Laser reflector 3 Prism 4 Imaging device 5 Case 6 Window 7 Electric sewing tube 8 Cutting tool 9 Bead part 10 Cutting tool holder 11 Cutting bead

Claims (3)

  Laser irradiation or scanning is performed on the inner surface of the welded surface of the ERW welded tube, and the reflected light obtained is imaged by an imaging device, and the circumferential profile of the inner surface of the tube and the image of the surface of the beaded portion of the inner surface of the tube are identical. A method for monitoring a welded part of an electric resistance welded pipe, wherein the welded part is displayed on a monitor screen.   A method for manufacturing an electro-welded welded pipe, comprising: controlling a pressing force of a bead cutting bite and a pressing force of a pipe making roll based on a circumferential profile of the pipe inner surface and an image of a bead cutting part surface of the pipe inner surface.   An optical detection means for housing a laser oscillator, a laser reflector, a prism, and an image pickup device, and a temperature adjusting means for measuring and cooling the inside of the optical detection means and an image pickup device, which are attached to a holder of an ERW weld bead cutting tool And a monitoring means for displaying on the monitor screen the image picked up in (1).