JPS6124271B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for welding a tank bottom plate.

Generally, tank bottom plates are assembled by butt welding a number of bottom plate members using backing metals on the foundation on which the tank is installed.

Conventionally, this type of welding method specifically includes the first welding method.
As shown in the figure, a backing metal c is arranged in a recess b provided on a foundation a, and the bottom plate members d and d are butted and placed on the backing metal c, and then welded, or as shown in Figure 2. As shown, a backing metal c is placed directly on the foundation a, and the bottom plate members d and d, which have been formed with a step, are butted and placed on the backing metal c, and then welded. Since gold c is a permanent backing metal, X-ray inspection of the welded part cannot be performed, and the backing metal part c has a structure where welding defects are likely to occur.

In view of these circumstances, the present invention has been made to provide a method for welding a tank bottom plate in which defective parts can be easily detected by performing an X-ray inspection after butt welding the bottom plate members together. The tank bottom plate members to be welded are placed on a foundation provided with grooves so that the abutting portions of the tank bottom plate members to be welded are located on the grooves, and then the abutting portions are sequentially welded from the upper surface side, and at the same time, the The present invention is characterized in that a backing metal moving device disposed so as to be in contact with the lower surface of the abutting portion is moved in accordance with the welding location.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 3 and 4, first, a foundation 2 is provided with a groove 1 of a required depth at a predetermined position, and tank bottom plate members 3, 3 are butted onto the foundation 2 on the groove 1. It is placed so that it looks like this. Next, a backing metal moving device 5 has a rotary backing metal 4 that supports the abutting portions of the bottom plate members 3, 3 in contact with the lower surfaces thereof.
is arranged in the groove 1, and a welding device 7 having a welding torch 6 for welding the grooves of the abutting portions of the bottom plate members 3, 3 is placed on the bottom plate member 3. A phototube type position synchronization device 8 is provided between the backing metal moving device 5 and the welding device 7 so that both can be moved synchronously.

In this state, the synchronizing device 8 is operated to move the backing metal moving device 5 and the welding device 7 in synchronism. In this way, the backing metal 4 of the backing metal moving device 5 supports the butt lower surfaces of the bottom plate members 3, 3, and at the same time, the torch 6 of the welding device 7 is used to open the bevel at the butt portion of the bottom plate members 3, 3. Weld them one after another. Note that the light from the tuning device 8 passes through the gap between the butt grooves of the bottom plate members 3, 3.

After welding the bottom plate members 3, 3 as described above, the backing metal moving device 5 is loaded from the groove 1, and the welding device 7 is removed from the top of the bottom plate member 3. Thereafter, as shown in FIGS. 5 and 6, a winding drum type X-ray film moving device 9 is placed in the groove 1, and an X-ray irradiator 10 is placed on the welded portion of the bottom plate member 3. . By activating an ultrasonic position tuning device 8' installed between the two, the film moving device 9 and the X-ray irradiation device 10 are moved in synchronism to perform an X-ray inspection of the welded portion. If the welded part has a defect as a result of the X-ray inspection, that part is welded again to make it defect-free.

After the X-ray inspection and repair work of the welded parts as necessary are completed, the trench 1 is filled with a removable filler such as sand so that it can be reused for inspection after tank operation.

Note that the position tuning device used in the above example includes:
In addition to the phototube method and the ultrasonic method, a limit switch method, an X-ray method, a cable winding method, etc. can also be adopted as appropriate.

As described above, according to the present invention, a foundation provided with a groove of a required depth is used, bottom plates placed on the foundation are brought into abutment on the groove, and a backing metal moving device is provided in the groove. Since the butt part is supported by the groove and at the same time welded by the welding device placed on the bottom plate member, X-ray inspection after welding can be performed using the groove, which improves reliability. This results in a welded structure with high quality and provides excellent effects such as the ability to obtain a high-quality tank bottom plate.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing a conventional tank bottom plate welding method, respectively, and FIG. 3 is a front view showing an example of a state in which the butt portions of bottom plate members are welded using the method of the present invention, Figure 4 is a side view of Figure 3, and Figure 5 is a side view.
The figure is a front view showing an example of a state in which an X-ray inspection is performed after welding the bottom plate members, and FIG. 6 is a side view of FIG. 5. DESCRIPTION OF SYMBOLS 1...Groove, 2...Foundation, 3...Bottom plate member, 5...Backing metal moving device, 7...Welding device.

Claims (1)

[Claims] 1. Arrange the tank bottom plate members to be welded on a foundation with grooves at predetermined positions so that the butt portions of the tank bottom plate members to be welded are located on the grooves, and then weld the butt portions sequentially from the upper surface side, and at the same time A method for welding a tank bottom plate, characterized in that a backing metal moving device disposed in a groove so as to be in contact with the lower surface of the abutting portion is moved in accordance with the welding location.