JPS6149787A - High speed and continuous tack welding method - Google Patents

Abstract

PURPOSE:To stabilize the formation of a bead, and to execute a stable tack welding at a high speed and continuously by using plural consumable electrodes, and making a pulse current for giving a phase difference flow to each adjacent electrode of the consumable electrodes. CONSTITUTION:A phase difference is given to a pulse current I1 flowing to a preceding electrode 1 and a pulse current I2 flowing to a following electrode 2. In case when a current value of the pulse current I1 flowing to the preceding electrode 1 is high, and a current value of the pulse current I2 flowing to the following electrode 2 becomes low, due to the phase difference, a position of a molten metal is made to flow to the following electrode 2 side. Subsequently, when the current value of the pulse current I1 flowing to the preceding electrode 1 becomes low, and the current value of the pulse current I2 flowing to the following electrode 2 becomes high, the molten metal moves to the preceding electrode 1 side. Accordingly, when the currents I1, I2 to which the phase difference has been given are conducted continuously to the electrodes 1, 2, the molten metal between both the electrodes 1, 2 are vibrated forward and backward. In this way, the position of the molten metal scarcely moves from between both the electrodes 1, 2, and the molten metal is obstructed from flowing out to the rear of the following electrode 2.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a high-speed continuous tack welding method in which tack welding is performed continuously at high speed using multi-electrode gas-shielded arc welding prior to main welding. be.

[Prior art]

Conventionally, tack welding prior to main welding has been performed by gas-shielded arc welding using a consumable electrode.

In this tack welding, for example, in the case of carbon dioxide arc welding using one electrode, the welding speed limit is about 4 to 4 minutes, and as shown in FIG.
Even if carbon dioxide arc welding is performed using an electrode, the welding speed limit is approximately 6%15+ at most. This is the fourth
In the conventional example shown in the figure, the welding power source uses direct current with the same polarity for both the leading electrode 1 and the trailing electrode 2, so the arc 7 of the leading electrode 1 and the arc 8 of the trailing electrode 2 strongly attract each other. , the attracted arc and molten metal are connected to both electrodes 1
, 2, but the molten metal fluctuates irregularly between both electrodes 1 and 2 due to slight fluctuations in the groove condition or welding conditions, and sometimes the trailing electrode 2 It passes through the passage and flows backwards. This is because when this phenomenon occurs, a large amount of spatter tends to occur and the bead shape tends to become discontinuous.

Therefore, if tack welding is performed at a welding speed that exceeds this welding speed limit, an irregular bead with a markedly uneven bead shape (1 ping beat °) will occur, resulting in slag entrainment and poor fusion during main welding. The current situation is that welding defects are likely to occur, and it is difficult to follow the weld line when performing main welding).Therefore, it is desired that a tack welding method with a very high welding speed be developed.

[Purpose of the invention]

The object of the present invention is to overcome the above-mentioned problems and to propose a high-speed continuous tack welding method that can perform tack welding continuously at high speed.

[Summary of the invention]

The high-speed continuous tack welding method of this invention uses a plurality of consumable electrodes, and by passing a pulse current with a current phase difference between adjacent electrodes of the consumable electrodes, the molten metal formed between the two electrodes is periodically This method applies vibrations to stabilize the relative positional relationship of the molten metal to the electrode, and performs tack welding continuously at high speed.

[Embodiments of the invention]

FIG. 1 is a block diagram showing an embodiment of the present invention, in which 4 is a power source for a welding device, and 5 is a pulse current supplied from the power source 4! A first pulse current generator 6 converts the current supplied from the power source 4 into a pulse current I2 having a phase difference with respect to the pulse current 11 supplied to the preceding electrode 1. This is a second pulsed current generator that supplies the row electrodes 2.

The pulse current 11 flowing through the leading electrode 1 is set to a current value necessary to obtain the penetration depth of the base metal, and the pulse current 2 flowing through the trailing electrode 2 is the molten metal melted by the leading electrode 1. The current value is set to be necessary and sufficient to prevent the pulse current II from flowing rapidly behind the trailing electrode 2, and for this reason, the current value is set to be lower than the pulse current II.

2(a) and 2(b) show the current waveforms of the pulse current ■□ flowing through the preceding electrode 1 and the pulse current I2 flowing through the trailing electrode 2. As shown in the figure, pulse current 1. A phase difference φ is given between the pulse current I2 and the pulse current I2.

The operation of the above-described high-speed tack welding method will be explained.

As shown in FIGS. 2(a) and 2(b), a pulse current 1. And the pulse current flowing to trailing electrode 2!
If a phase difference φ is given to the current value, the current value of the pulse current 11 flowing to the leading electrode 1 becomes high and the current value of the pulse current I2 flowing to the trailing electrode 2 becomes low due to this phase difference φ. 6. As shown in FIG. 6(a), the arc 7. of both electrodes 1, 2.
8) The position of the generated molten metal 3 is moved to the trailing electrode 2 side. Next, when the current value of the pulse current If flowing through the leading electrode 1 is low ((low)) and the current value of the pulse current I2 flowing through the trailing electrode 2 is high, the molten metal 3 between the electrodes 1 and 2 is ) Move toward the leading electrode 1 side as shown in K. Therefore, as shown in FIG. 2, the pulse current 1. , I
2 to the leading electrode 1 and the trailing electrode 2), the molten metal 6 between the electrodes 1 and 2 is passed through the pulsed current II.
* Can be vibrated back and forth depending on the amplitude of 12.

As a result of applying vibration to the molten metal 6, the position of the molten metal 6 hardly moves from between the electrodes 1 and 2 even if the welding conditions such as the cutting edge state and welding speed change slightly.
Therefore, the trailing electrode 2 can effectively block the molten metal b) 6, and can prevent it from flowing out to the rear of the trailing electrode 2.

Therefore, the weld bead can be formed more stably.

Therefore, even if the tack welding speed is increased, bead formation is stable, and smooth weld beads can be obtained continuously even at high speeds.

Next, the results of tack welding according to the above embodiment will be shown together with a conventional example. In other words, we performed tack welding on a Y-groove with a groove angle of 90 degrees and a depth of 4 using a silver plate with a thickness of 12 mm, and determined the limit of welding speed that does not produce irregular beads. According to the examples shown in Table 1, the welding speed limit when tack welding according to the present invention is performed is 12η min. It is possible to achieve a significant improvement compared to the 6W when performing this.

Note that the welding current value and pulse frequency of the pulse current are not limited to the values shown in Table 1, and the pulse waveform is not limited to the shape shown in FIG. 2.

〔Effect of the invention〕

As explained above, this invention uses a plurality of consumable electrodes, and by passing a pulse current with a phase difference between adjacent electrodes of the consumable electrodes, the molten metal between the electrodes is vibrated by an arc. , bead formation can be stabilized, and stable tack welding can be performed continuously at high speed. Furthermore, by changing the time ratio of the pulse current and the height ratio of the current, tack welding can be performed in accordance with the tack welding speed, and weld defects in main welding can be prevented.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 (
a) and (b) are welding current waveform diagrams of the embodiment shown in Fig. 1, Fig. 3 (a) and (b) are operation explanatory diagrams of the embodiment shown in Fig. 1, and Fig. 4 is a welding current waveform diagram of the embodiment shown in Fig. 1. FIG. 3 is an arc configuration diagram of conventional two-electrode plate welding. 1... Leading electrode, 2... Trailing 1! Pole, 3... Molten metal, 4... Power supply, 5... First pulse current generator, 6... Second pulse current generator, 7.8... Arc, 11... - Pulse current of the leading electrode, I2... Pulse current of the trailing electrode. Agent Patent Attorney Sanro Kimura Figure 1 Figure 2 Figure 3 Figure 4 (a) (b)

Claims (1)

[Claims] In gas-shielded arc welding, multiple consumable electrodes are used and a pulsed current with a phase difference is passed between adjacent consumable electrodes to form a stable molten metal between the adjacent consumable electrodes while tack welding is performed. A high-speed continuous tack welding method characterized by performing.