JPH05141B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a circumferential automatic welding method and apparatus used for welding and connecting underground pipelines, plant piping, etc. [Conventional technology] When joining pipes by butt welding, TIG welding using a hand stick is popular, and automatic TIG circumferential automatic welding equipment is also available, but in both cases, an operator operates directly and manually near the equipment. It was common to do so. When welding and connecting underground pipelines, plant piping, etc., welding is almost always done within narrow excavated trenches, and the footing is often poor. Therefore, from the viewpoint of improving the working environment and safety, we have developed a circumferential TIG for on-site welding that can be remotely controlled.
The development of automatic welding methods and equipment has been long awaited. [Problems to be Solved by the Invention] In such a case, the present invention provides a method and an apparatus for automatically performing high-quality circumferential welding without having to dig holes for manual welding of butt welds. The purpose is to [Means for Solving the Problems] The present invention enables remote control welding and facilitates on-site welding. A coaxial annular guide is attached to the welding head, and the welding head is run along this guide to capture the arc image and collect the arc sound. This automatic circumferential welding method is characterized by continuously welding the circumference of a pipe by adjusting welding conditions while visually and audibly observing and listening to the welding conditions. The method of the present invention is
It can be applied to TIG, MIG, and other welding processes. The device of the present invention is equipped with a special filter and an ultra-small CCD (Carge Coupled Device) camera so that arc images can be clearly captured in the welding head, and an acoustic pickup that constantly collects arc sounds. Equipped with a display to display images and a speaker to check for abnormalities in welding before any changes appear in the images, welding conditions can be adjusted remotely through dual simultaneous monitoring of sound and images. This device is equipped with a device that allows automatic circumferential welding at the pipe installation site. It is extremely preferable to use the device of the present invention as a TIG welding device because it generates almost no smoke and can easily capture and obtain clear images. In this case, the device of the present invention specifically includes the following technical means. (1) A welding head equipped with a traveling device that runs along a circumferential guide; (2) a CCD with a special filter on one side centered on and close to the tungsten electrode with an appropriate inclination angle; A TIG welding head equipped with a camera and an acoustic pickup (microphone), with an arc illumination light set at an appropriate angle to face it; (3) A display and microphone that displays images taken by the CCD camera as clear arc images. (4) A TIG circumferential automatic welding adjustment device that remotely controls welding conditions while simultaneously monitoring two elements: video and sound. It is configured. Furthermore, (5) in the case of thick-walled tubes, a nozzle is provided to spray archon gas around the outer circumference of the camera to avoid damage from the camera's radiant heat. [Function] According to the method of the present invention, continuous automatic welding can be performed remotely while keeping track of the arc image and arc sound of the pipe butt weld. Therefore, there is no need to dig a hall,
High-quality welding can be performed continuously and automatically. The device of the present invention can easily and reliably implement the method of the present invention. The welding head used in the present invention is lightweight and has a maximum machine height of about 200 mm, so there is no need to dig a hole, and there is no need to crawl under the pipe to monitor the welding arc when welding in an upward position. Ta. This device can record images on videotape, contributing to quality control and technical improvement. [Example] FIG. 1 shows an overall system diagram of the apparatus of the present invention used for carrying out the method of the present invention. The device of the invention is extremely useful for butt welding of buried pipes. . A welding head 3 is installed in the excavated groove on the outer periphery of the steel pipe 1 via a guide 2. As the automatic welding head, we used an automatic machine manufactured by Dimetrix, Inc., which has a low machine height, with the aim of eliminating the need for digging holes. With this equipment, if there is a clearance of 250 mm around the pipe, welding can be performed without any problem. At the same time, an arc welding color monitor device was attached to this welding head to enable remote welding. The above-ground part is equipped with a welding power supply device 4, an arc shielding gas cylinder 5, a remote control panel 7, a programmer box 6 for presetting welding conditions, and the like. The programmer box 6 is connected to the welding power source 4 via a cable 13, and the remote control panel 7 is connected to the welding head 3 via a monitor cable 14.
is combined with Further, the welding head 3 is operated from a welding power source 4 via a cable 15. 1
7 and 18 are power cables. When welding begins, the operator must constantly monitor the arc image displayed on the display 8 and the regular arc sound coming from the speaker 9, and rotate and adjust the dial 10 on the operation panel 7 as appropriate to prevent abnormal situations from occurring. become. Note that 11 is an amplifier and 12 is a video device. Figure 2 shows the main parts of the welding head. Figure 2 shows
It shows the situation during construction of the first outer circumference. A tungsten electrode 22 stands perpendicularly to the surface of the tube 1 in the center. A 300,000-pixel color CCD camera 26 and an acoustic pickup (condenser microphone) 27 equipped with a noiseless circuit are installed parallel to this from a 30-degree direction to the left, and both capture arc images and arc sounds. There is. The CCD camera is equipped with a special filter 25. On the other hand, a 150W Haroken lamp 28 is projected from a 30 degree direction to the right while the arc is in operation. The welding wire 24 is continuously fed near the tungsten electrode from the left side at 15 degrees during welding. Figure 2 shows the case where the cart is moving counterclockwise, but when welding in the opposite direction, the CCD camera 2, microphone 27 and halogen lamp 28 are rotated 180 degrees around the welding torch, and the direction shown in Figure 2 is The welding will proceed with the positions being reversed. In addition, in order to avoid radiant heat from welding the CCD camera 26, when welding a thick pipe, a thin copper tube is wound around the camera's outer circumference in a spiral shape, and a large number of holes are drilled on the outer surface of the thin copper tube for arc shielding. It is best to constantly spray the argon gas used as the gas. In addition, the special filter 25 provided to capture the arc light as a clear image is as shown in FIG.
Transparent glass 41, polarizing filter 42, interference filter 43, polarizing filter 44, color filter 45
It consists of Next, an example will be shown in which the method of the present invention was implemented using the apparatus of the present invention. Welding conditions were as follows. Circumferential welding of carbon steel pipe Steel pipe: 350A x 7.9t Welding material: Wire KT-50 (φ1.0) Shielding gas Argon (15/min) Bevel shape: As shown in Fig. 4 Plate thickness (51): 7.9mm Open Tip angle (52): 90 to 100 degrees Root section (53): 0.5 mm Root section thickness (54): 0.5 to 1.0 mm Welding conditions: TIG welding

〔Effect of the invention〕

The method of the present invention is also suitable for low pulse mode welding and synchronized pulse mode welding, and can perform high-quality initial layer welding and filler pass welding. According to the device of the present invention, there is no need to dig holes, and remote control welding can now be carried out smoothly and reliably on the ground. Therefore, in the case of on-site piping work, it has become possible to reduce the amount of earth and sand excavated and backfilled, reduce the area occupied by the work, shorten the construction period, and reduce costs. Also, as shown in the above example, it can be applied to a V-shaped groove instead of the general U-shaped groove,
Bevel processing costs can now be reduced by approximately 20%. Additionally, video recording became possible, making quality control easier.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the overall configuration of the device of the present invention;
Figure 2 is a side view showing details of the welding head.
FIG. 3 is a configuration diagram of the filter, and FIG. 4 is a diagram of the groove shape of the embodiment. DESCRIPTION OF SYMBOLS 1...Pipe, 2...Guide, 3...Welding head, 4...Welding power supply device, 5...Gas cylinder, 6...Programmer box, 7...Remote control panel, 8...Display, 9
...Speaker, 10...Dial, 22...Tungsten electrode, 24...Welding wire, 25...Filter, 2
6...CCD camera, 27...acoustic pickup (condenser microphone), 28...halogen lamp.

Claims (1)

[Claims] 1. When butt welding a pipe, an annular guide coaxial with the pipe is attached to the outer periphery of the pipe, the welding head is run along the guide, and an arc image is captured and arc sound is recorded. 1. A circumferential automatic welding method characterized in that the pipe is continuously welded circumferentially by collecting sound, and adjusting welding conditions based on the captured image and the collected sound. 2. A welding head that moves by itself along a circumferential guide;
A circumferential automatic welding device characterized in that it is equipped with a CCD camera and an audio pickup mounted on the welding head, a display and an audio speaker for displaying images taken by the CCD camera, and an adjustment device for adjusting the welding conditions of the welding head. Welding equipment. 3. The device according to claim 2, further comprising a gas injection nozzle facing the CCD camera.