JPS6018271B2 - Welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding method in which automatic welding equipment automatically corrects the position of a welding torch in the direction perpendicular to the joint line and performs follow-up control (joint copying). This invention relates to an improvement in the welding method that improves the quality of the welding process.

2. Description of the Related Art In general, a method using an arc generated between an object to be welded and an electrode is known as a joint tracing method for automatic welding equipment.

Since the arc voltage of the arc changes depending on the distance between the workpiece and the electrode, by detecting this arc voltage, it is possible to detect that the arc has contacted the wall surface of the joint. Conventionally, in this type of groove tracing method, the arc is moved within the joint in a direction perpendicular to the joint line, and it is detected by the arc voltage that the arc hits one wall surface of the joint due to this movement. The moving direction of the arc is then reversed, and the fact that the arc hits the other wall surface of the joint due to this reversed movement is detected by the arc voltage, and the moving direction of the arc is further reversed. By repeatedly reversing the arc as described above, the deviation in the direction perpendicular to the line of interest can be corrected, and automatic control of the localization layer can be performed. In the conventional welding method described above, wall surfaces on both sides are required in order to follow the Kansai line.

Therefore, there was a drawback that it could not be applied to a one-layer, two-pass narrow-gap welding method that required accurate tracing of one wall surface of the joint. The present invention eliminates the above drawbacks and
The present invention provides a welding method in an automatic welding device using arc voltage detection, which is also applicable to a one-layer, two-pass narrow gap welding method.

Below, automatic welding equipment (one layer, two layers) to which the method of the present invention is applied
An example of pass GMA narrow gap welding will be described in detail with reference to the figure.

FIG. 1 shows an outline of this automatic welding device.
In FIG. 1, 1 and 2 are base materials, 3 is a backing metal, 4 is a rail provided on the base material 1, and 5 is a welding cart that moves along this rail 4. A left-right copying slide section 6 is attached to this welding cart 5 so as to be movable in the directions of arrows A and B, and this slide section 6 is moved by a motor 7 provided on the above-mentioned cart 5 according to the rotation direction of the arrow A. Or it is moved in direction B. A vertical adjustment slide part 8 is attached to the slide part 6 so as to be movable in the directions of arrows C and D, and this slide part 8 is moved in accordance with the direction of rotation by a motor 9 provided on the slide part 6. It is moved in the C or D direction. Reference numeral 1 indicates a welding torch, which is attached to the slide portion 8, and is equipped with a welding tip 11.
is attached, and a welding wire 12 is attached to this tip 11. In this way, the configurations described with reference numerals 1 to 12 are well known in automatic welding equipment. code 1
Reference numeral 3 denotes a voltage detector, which detects the arc voltage of an arc 14 (see FIG. 3) generated between an electrode made of wire 12 and a workpiece made of base material 2, as is well known. 15 is a reference voltage generator, the output voltage of which is applied to a comparator 16 and compared with the above-mentioned arc voltage.

The output of this comparator 16 is the timer 17 and the gutter switching device 1.
The signal is supplied to the motor 7 via the motor 8, and the motor is driven. In the automatic welding apparatus shown in FIG. 1, the cart 5 is moved along the rail 4, and the arc 14 is also moved approximately along the groove line.

The wall surfaces 19 and 20 of this groove are formed by the base materials 1 and 2. FIG. 2 shows the movement of the arc 14 within the junction, and only one wall surface 20 (covered wall) is shown. When the slide part 6 is moved in the direction of arrow A by the motor 7 when the arc 14 is at the position of the point Po, the cart 5 also moves as described above, so the arc 14 (wire 12) is attached to the wall surface 2 obliquely. approach from that direction. This approach shortens the arc length of the arc 14 and lowers the arc voltage. This arc voltage is detected by voltage detector 1
3 and compared with the reference voltage from the reference voltage generator 15 in the comparator 16, and when they match, that is, the welding signal and the reference signal match, the polarity converter 18 sends the signal to the motor 7. Slide 6 by reversing the drive current of
is moved in the direction of arrow B, and at the same time the timer 17 starts operating. The position of the arc 14 when the welding signal and the reference signal match is the point P in FIG. The wire 12 and arc 14 at this time are shown by solid lines in FIG. Using this point P as a turning point two degrees closer to the wall, the slide portion 6 is moved in the direction of arrow B for a certain period of time set by the timer 17.
The position of the arc 14 after this certain period of time has elapsed is indicated by point P2 in FIG.
It comes to the position indicated by chain lines 14' and 12' in the figure. This point P
2 as a turning point away from the wall surface 20, the polarity cutter 18 is operated by the timer 17, and the motor 7
is reversed again and the slide portion 6 is moved in the direction of arrow A. As mentioned above, when the arc 14 approaches the wall by two degrees, the slide part 6 is moved in the direction of arrow B, and after the slide part 6 is moved in the direction of arrow B for a certain period of time, the slide part 6 is moved in the direction of arrow A.
By moving the arc 14 in this direction, the arc 14 moves repeatedly to points P, , P2, P3, P4, P5, . . . in FIG. The moving speed Y of the arc 14 (see Fig. 2) and the setting time of the timer 17 are set so that welding defects will not occur, depending on the welding speed x, welding current (arc), groove width and plate thickness of the workpiece. To be determined accordingly.

Further, by adjusting the reference voltage of the reference voltage generator 15, the distance at which the arc 14 approaches the wall surface 20 is controlled, and by adjusting the set time of the timer 17, the distance away from the wall surface 20 is controlled, The arc 14 always hits the wall surface 20 as shown in Fig. 3, and the corners of the groove can be melted appropriately.
It is possible to solve the problem of insufficient groove corner melting that occurs in GMA narrow gap welding. As described above, the present invention is effective for one-layer, two-pass narrow gap welding by accurately tracing one wall surface of a groove.

Incidentally, since single-layer, two-pass GMA narrow gap welding is the same as fillet welding if only one wall is considered, it goes without saying that the present invention can be used after fillet welding.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an example of a device to which the present invention is applied, FIG. 2 is an operation diagram showing the operation of the device in FIG. 1, and FIG.
It is an enlarged view of a part of the figure. 6...Slide part, 7...Motor, 10...Welding torch, 12...Welding wire, 13...Voltage detector, 14...Arc, 15... Reference voltage generator, 16... comparator, 17... timer. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 Compare the welding arc voltage at one corner of the groove with the reference arc voltage, and when these arc voltages match, the welding wire will move away from one wall of the groove in the direction perpendicular to the groove line. The welding torch is moved, the period of this movement is limited to a certain period of time by a timer, and after this certain period of time has elapsed, the welding torch is moved in the direction in which the welding wire approaches the above-mentioned wall surface, and the same process is continued from then on to form the bevel. A welding method characterized by continuing welding along a line.