JP2013202626A - Manufacturing device for welded steel pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing device for a welded steel pipe which achieves correctly grasping a state of inner face welding.SOLUTION: A manufacturing device 1 for a welded steel pipe includes: an outer face welding torch 4 performing outer face welding on an open pipe 2 to make a welded steel pipe 5; and an inner face welding torch 6 for performing inner face welding on the welded steel pipe 5. A laser displacement gauge 11 is arranged at a part positioned on the downstream side of the outer face welding torch 4. An arc monitoring camera 12 is arranged between the laser displacement gauge 11 and the inner face welding torch 6. In addition, a laser displacement gauge 13 is arranged on the downstream side of the inner face welding torch 6. The laser displacement gauge 11, the arc monitoring camera 12 and the laser displacement gauge 13 are respectively provided inside the welded steel pipe 5, which allows to directly monitor a state of an inner face bead 5a after the outer face welding, a state of the arc generated from the inner face welding torch 6, and a state of an inner face bead 5b after the inner face welding.

Description

  The present invention relates to a welded steel pipe manufacturing apparatus.

  When manufacturing a welded steel pipe, first, a cylindrical open pipe is formed by sequentially bending a strip-shaped steel plate with a forming roll, and then a portion where the ends of the open pipe are butted together is welded from the outer surface side (outer surface). welding). An inner surface bead is formed on the inner surface of the pipe by this outer surface welding, but the inner surface bead may cause a problem depending on the quality required for the tube. Therefore, inner surface welding is performed to melt and smooth the inner surface bead. Since the inner surface welding is performed using an inner surface welding torch arranged inside the pipe, the state cannot be visually confirmed from the outside of the pipe. Therefore, Patent Document 1 describes that it is determined whether or not the inner surface welding is properly performed using a visual camera and a surface temperature sensor arranged on the outer side of the pipe.

  According to Patent Document 1, a surface red hot part that appears on the outer surface of a pipe at the time of inner surface welding is imaged by a visual camera, and the center position of the surface red hot part is obtained from the imaging data by arithmetic processing. The obtained center position is assumed to be the position of the inner surface welding torch, and whether the position of the outer surface welding torch and the position of the inner surface welding torch are on the same straight line, that is, the inner surface welding has matched the ends of the open pipes. It is determined whether or not it is made for the part. On the other hand, a non-contact type surface temperature sensor arranged outside the tube as with the visual camera detects the temperature of the surface red hot part. The temperature detected by the surface temperature sensor is converted into the amount of heat input to the inner surface bead by the inner surface welding torch. It is determined whether or not the distance between them is appropriate.

Japanese Patent No. 2761718

  However, both the visual camera and the surface temperature sensor described in Patent Document 1 are arranged outside the pipe, and do not directly monitor the state of the inner surface welding and the state of the inner surface bead after welding inside the pipe. Therefore, the following problems arise. First, regarding the imaging of the surface red hot part with a visual camera, the surface red hot part becomes difficult to appear as the thickness of the steel sheet increases. For example, when a steel sheet having a thickness exceeding 6 mm is used, the surface red hot part is accurately recognized from the appearance. It will be difficult to do. In addition, regarding the temperature measurement by the surface temperature sensor, when converting the temperature on the inner side of the tube based on the temperature on the outer side, the plate thickness and material of the steel plate, or the heat generated by the outer surface welding torch acts as a disturbance factor It becomes difficult to accurately measure the heat input to the inner surface bead.

  Further, for example, when electrode wear or the like of the inner surface welding torch occurs, even if the position of the inner surface welding torch is appropriate, a positional deviation occurs between the inner surface bead and the arc generated from the electrode. In this case, since it is impossible to monitor the arc from the outside of the tube, it is not possible to detect even if a welding failure occurs due to the misalignment of the arc. As described above, the invention described in Patent Document 1 does not directly monitor and determine the state of the inner surface welding, but rather presume based on the state on the outer surface side of the pipe. There is a problem that it may be difficult to accurately grasp the state of welding.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a welded steel pipe manufacturing apparatus that can accurately grasp the state of inner surface welding.

  An apparatus for manufacturing a welded steel pipe according to the present invention includes a forming means for forming a cylindrical open pipe by sequentially bending a strip-shaped steel pipe, and an open pipe outer peripheral side, and the ends of the open pipe are butted together. An outer surface welding torch that welds a part to form a welded steel pipe, and an inner surface that is disposed on the downstream side of the outer surface welding torch inside the welded steel pipe and is formed on the inner surface of the welded steel pipe during welding with the outer surface welding torch The present invention relates to an apparatus for manufacturing a welded steel pipe having an inner surface welding torch for welding to a bead, and is disposed in a portion located between the outer surface welding torch and the inner surface welding torch inside the welded steel pipe. A first monitoring means capable of measuring the shape, a second monitoring means arranged inside the welded steel pipe and capable of imaging an arc generated by the inner surface welding torch, and the inside of the welded steel pipe Is arranged at a portion located downstream of the Oite inner surface welding torch, is characterized in that further comprising a third monitoring means capable of measuring the shape of the inner surface bead.

  A displacement sensor capable of detecting the height of the inner surface bead can be used as the first monitoring unit and the third monitoring unit.

  According to the present invention, the inner surface welding is appropriately performed based on the comparison between the inner surface bead shape immediately after the outer surface welding measured by the first monitoring means and the inner surface bead shape immediately after the inner surface welding measured by the third monitoring means. It is possible to directly determine whether the inner bead has a desired shape. Further, when the shape of the inner surface bead becomes abnormal, it can be determined whether the cause is due to an abnormality during outer surface welding or an abnormality during inner surface welding. Furthermore, since the arc generated by the inner surface welding torch can be directly monitored by the second monitoring means, the arc position is shifted from the position to be welded, or the arc is normally generated due to electrode wear of the inner surface welding torch. Even if it disappears, an abnormality can be detected immediately. Thus, since the welded steel pipe manufacturing apparatus according to the present invention directly monitors the arc generated by the inner surface bead and the inner surface welding torch, it is possible to accurately grasp the state of the inner surface welding. .

1 is a cross-sectional side view schematically showing a welded steel pipe manufacturing apparatus according to an embodiment of the present invention. It is the schematic which illustrates the inner surface bead formed in a welded steel pipe in the welded steel pipe manufacturing apparatus which concerns on embodiment of this invention, (a) shows the inner surface bead after outer surface welding, (b) is after inner surface welding. The inner bead of is shown. It is the schematic which illustrates the arc which the 2nd monitoring means imaged in the manufacturing apparatus of the welded steel pipe which concerns on embodiment of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment FIG. 1 schematically shows a welded steel pipe manufacturing apparatus 1 (hereinafter referred to as a manufacturing apparatus 1) according to an embodiment of the present invention. The manufacturing apparatus 1 includes a forming roll 3 for forming a cylindrical open pipe 2 by curving a strip-shaped steel plate (not shown). 1 shows only one forming roll 3, but as is well known, the manufacturing apparatus 1 includes a plurality of forming rolls (not shown). The open pipe 2 is formed by sequentially bending these forming rolls while feeding the steel plate in the direction indicated by the arrow A.

  In addition, an outer surface welding torch 4 is disposed at a site located on the outer side of the open pipe 2 on the downstream side of the forming roll 3. The outer surface welding torch 4 is for performing so-called outer surface welding, in which the portion 2a where the ends of the open pipe 2 are butted together is TIG welded from the outer surface side, and is opened by the outer surface welding of the portion 2a. The pipe 2 becomes the welded steel pipe 5.

  An inner surface welding torch 6 for performing so-called inner surface welding, in which the welded steel tube 5 is TIG-welded from the inner side, is disposed in a portion located downstream of the outer surface welding torch 4 inside the welded steel tube 5. The inner surface welding torch 6 is for melting and smoothing the inner surface bead 5a formed on the inner surface of the welded steel pipe 5 during outer surface welding, and is a substantially cylindrical inner surface weld inserted into the welded steel pipe 5. The rod 7 is supported via a support block 8. Here, the support block 8 has a tapered surface 8a at the upper part on the inner surface bead 5a side, and the inner surface welding torch 6 can slide on the tapered surface 8a.

  That is, the inner surface welding torch 6 can move up and down in the welded steel pipe 5 by sliding on the tapered surface 8a, whereby the distance between the inner surface bead 5a and the inner surface welding torch 6 is appropriately adjusted. In addition, a cooling water pipe 9 for supplying cooling water to the inner surface welding torch 6 and a gas supply pipe 10 for supplying welding shield gas are inserted into the inner surface welding rod 7. Is connected to the internal welding torch 6 via the support block 8.

  In the manufacturing apparatus 1 configured as described above, a laser is provided as a first monitoring means capable of measuring the shape of the inner surface bead 5a inside the welded steel pipe 5 positioned between the outer surface welding torch 4 and the inner surface welding torch 6. A displacement meter 11 is provided. Further, an arc monitoring camera 12 is provided as a second monitoring means capable of imaging an arc generated by the inner surface welding torch 6 in a portion located between the laser displacement meter 11 and the inner surface welding torch 6 inside the welded steel pipe 5. It has been. Further, as a third monitoring means capable of measuring the shape of the inner surface bead 5b smoothed by performing inner surface welding with the inner surface welding torch 6 at a position located downstream of the inner surface welding torch 6 inside the welded steel pipe 5. A laser displacement meter 13 is provided.

  The laser displacement meter 11 measures the shape of the periphery of the inner surface bead 5a three-dimensionally by irradiating the periphery of the inner surface bead 5a and receiving the reflected laser. Therefore, for example, when the point P shown in FIG. 2A is used as the reference edge, the height h1 of the inner surface bead 5a with respect to the reference edge P is detected by the laser displacement meter 11. Similarly, the laser displacement meter 13 measures the shape around the inner surface bead 5b smoothed by inner surface welding three-dimensionally with a laser. Therefore, when the shape desired as the inner surface bead 5b is a flat shape as shown in FIG. 2B, if the inner surface welding by the inner surface welding torch 6 is properly performed, the height of the inner surface bead 5b with respect to the reference edge P is increased. Is detected as approximately zero.

  On the other hand, if the desired shape is not obtained, for example, like the inner surface bead 5b 'indicated by the alternate long and short dash line due to some abnormality, the laser displacement meter 13 detects the height h2 with respect to the reference edge P. As shown in FIG. 1, the cables 11a and 13a of the laser displacement meters 11 and 13 are pulled out to the outside of the welded steel pipe 5 through the inside of the inner surface welding rod 7, and are connected to a control device (not shown). This control device compares the shape measurement result of the inner surface bead 5a by the laser displacement meter 11, the shape measurement result of the inner surface bead 5b by the laser displacement meter 13, and a predetermined threshold value set in advance, and based on the comparison result, outer surface welding is performed. It is possible to determine whether or not the inner surface welding is properly performed, that is, whether or not the inner surface beads 5a and 5b have a desired shape.

  The arc monitoring camera 12 captures an arc generated by the inner surface welding torch 6 in a visible state by combining a CCD camera and a light control filter, for example. Further, the cable 12a of the arc monitoring camera 12 is drawn out of the welded steel pipe 5 through the inside of the inner surface welding rod 7, and is connected to a monitor (not shown), so that the imaged arc can be confirmed visually. It has become.

Next, the operation and action of the welded steel pipe manufacturing apparatus 1 according to the present embodiment will be described.
As shown in FIG. 1, first, an open pipe 2 is formed by sequentially bending a strip-shaped steel plate (not shown) with a forming roll 3 or the like. Next, a portion 2 a where the end portions of the open pipe 2 are butted together is welded to the outer surface by the outer surface welding torch 4 to form a welded steel pipe 5. Further, the inner surface bead 5a formed during the outer surface welding is subjected to inner surface welding by the inner surface welding torch 6 so that the inner surface bead 5a is smoothed to become the inner surface bead 5b.

  Prior to the start of production of the welded steel pipe 5, the distance between the inner surface bead 5a and the inner surface welding torch 6 is adjusted by sliding the inner surface welding torch 6 up and down by sliding on the tapered surface 8a of the support block 8. Moreover, the raising / lowering amount of the inner surface welding torch 6 is appropriately determined according to the diameter of the welded steel pipe 5 to be manufactured, the state of the inner surface bead 5a after the outer surface welding, or the desired shape of the inner surface bead 5b.

  When the production of the welded steel pipe 5 is started as described above, the shape measurement of the inner surface beads 5a and 5b by the laser displacement meters 11 and 13 and the imaging of the arc by the arc monitoring camera 12 are started. Here, when the outer surface welding by the outer surface welding torch 4 is properly performed, the height h1 of the inner surface bead 5a shown in FIG. 2A is within a preset threshold value. Further, when the outer surface welding is properly performed and the inner surface welding by the inner surface welding torch 6 is also performed properly, that is, the arc imaged by the arc monitoring camera 12 is shown as a region R in FIG. 2B, the shape of the inner surface bead 5b is flat as shown in FIG. 2B, and the height of the inner surface bead 5b with respect to the reference edge P is detected as substantially zero.

  On the other hand, if an abnormality occurs during the outer surface welding or the inner surface welding and the desired shape is not obtained like the inner surface bead 5b ′ shown by the alternate long and short dash line in FIG. Is detected as an abnormal value. Here, when the abnormality of the inner surface welding occurs due to the outer surface welding by the outer surface welding torch 4, the height h1 of the inner surface bead 5a detected by the laser displacement meter 11 is also detected as an abnormal value. That is, by comparing the detection result of the inner surface bead 5a by the laser displacement meter 11 and the detection result of the inner surface bead 5b ′ by the laser displacement meter 13, it is possible to immediately grasp where the abnormality has occurred and respond accordingly. Is possible.

  Further, for example, when an abnormality in internal welding occurs due to electrode wear or the like of the internal welding torch 6, the arc generated from the internal welding torch 6 is applied to the internal bead 5a as indicated by a region R 'in FIG. On the other hand, the position is shifted. Since this arc R ′ can be confirmed by visually observing an image output from the arc monitoring camera 12 to a monitor (not shown), it is possible to immediately determine the presence or absence of an abnormality and cope with it.

  As described above, according to the welded steel pipe manufacturing apparatus 1 according to the present embodiment, the shape of the inner surface bead 5 a immediately after outer surface welding measured by the laser displacement meter 11 and the laser displacement meter 13 are used. Based on a comparison with the shape of the inner surface bead 5b immediately after the inner surface welding, it is directly determined whether the inner surface welding is properly performed, that is, whether the inner surface bead 5b after the inner surface welding has a desired shape. Can be judged. Further, when the shape of the inner surface bead 5b becomes abnormal, it can be easily determined whether the cause is due to abnormality during outer surface welding or abnormality during inner surface welding. Further, since the arc generated by the inner surface welding torch 6 can be directly monitored by the arc monitoring camera 12, the arc is not generated normally due to electrode wear of the inner surface welding torch 6 or the position of the arc is to be welded. Even if it deviates from the above, an abnormality can be detected immediately. Thus, since the welded steel pipe manufacturing apparatus 1 directly monitors the inner surface beads 5a and 5b and the arc R, it is possible to accurately grasp the state of inner surface welding.

  In the above-described embodiment, the laser displacement meters 11 and 13 are used as the first monitoring means and the third monitoring means for measuring the shape of the inner surface bead. However, these monitoring means are not limited to the laser displacement meter. . For example, a CCD camera or the like can be used as the first monitoring means and the third monitoring means, and the shape of the inner bead can be recognized from the image data obtained by the CCD camera.

  In the above-described embodiment, the arc monitoring camera 12 as the second monitoring means is arranged on the upstream side of the inner surface welding torch 6, but the position of the second monitoring means is not limited. If the state of the arc can be monitored, it can be arranged downstream of the inner surface welding torch 6.

  Furthermore, in the above-described embodiment, the case where the shape desired as the inner surface bead is a flat shape as shown in FIG. 2B has been described as an example, but is not limited to this inner surface bead shape, For example, the present invention can be applied to various desired inner surface bead shapes, for example, when the inner surface bead height h2 in FIG.

  DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of welded steel pipe, 2 Open pipe, 3 Forming roll, 4 Outer surface welding torch, 5 Welded steel pipe, 6 Inner surface welding torch, 11 Laser displacement meter (1st monitoring means), 12 Arc monitoring camera (2nd monitoring means) , 13 Laser displacement meter (third monitoring means).

Claims (2)

Forming means for sequentially bending the strip-shaped steel pipe to form a cylindrical open pipe;
An outer surface welding torch which is disposed on the outer peripheral side of the open pipe and welds a portion where the ends of the open pipe are butted together to form a welded steel pipe;
An inner surface welding torch which is disposed in a portion located downstream of the outer surface welding torch inside the welded steel pipe and welds to an inner surface bead formed on the inner surface of the welded steel tube during welding by the outer surface welding torch. In a welded steel pipe manufacturing apparatus comprising:
A first monitoring means disposed in a portion located between the outer surface welding torch and the inner surface welding torch inside the welded steel pipe and capable of measuring the shape of the inner surface bead;
Second monitoring means arranged inside the welded steel pipe and capable of imaging an arc generated by the inner surface welding torch;
An apparatus for manufacturing a welded steel pipe, further comprising: third monitoring means disposed in a portion located downstream of the inner surface welding torch inside the welded steel pipe and capable of measuring the shape of the inner surface bead.   The welded steel pipe manufacturing apparatus according to claim 1, wherein the first monitoring unit and the third monitoring unit are displacement sensors capable of detecting a height of the inner surface bead.

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