JPS6021027B2 - Consumable electrode arc welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to consumable electrode semi-automatic or automatic arc welding processes such as MG welding and non-gas arc welding.

Follower, small diameter wire (wire diameter 0.90~2.40)
In semi-automatic or automatic arc welding using a welding machine, welding conditions such as welding current, welding voltage, and wire feed speed are changed periodically to melt joints and deposited metal when the current is high, and to melt the molten metal when the current is low. Welding methods that are performed while cooling and preventing dripping are widely known.

In this hot saddle method, it is easy to ensure that the wire enters the base metal, but when the welding torch is moved along the welding line, there are problems such as insufficient pead width and insufficient width.
Therefore, the welding torch is vibrated in the direction across the welding line,
It is widely practiced to perform welding by matching changes in welding conditions at a specific point of vibration. However, the conventional welding method described above has the following problems. In the case of joint welding, as shown in Fig. 1, even if the wire 1 is vibrated as shown in a, a large metal bridge B cannot be obtained, and therefore,
Since distributed welding is required for wide grooves, welding becomes difficult in narrow areas and there is a risk of welding defects occurring at corners and the like.

In addition, in the case of horizontal butt welding, as shown in Fig. 2, even if the wire 1 is vibrated as shown in b, welding is performed in such a state that the weld metal 5 is raised between the base metals 3 and 4. Therefore, it is not possible to obtain a sufficient exchange speed. This invention solves the above-mentioned problems in conventional consumable electrode type arc welding.It is possible to obtain large metal bridges or hair-wave peeds, and to form good welded parts. The purpose is to provide law.

This invention will be explained in detail below.

In this invention, the welding current is changed periodically and the wire is vibrated in a direction across the welding line at least once during a period when the welding current is at a high value.

There is also a method of welding a secondary weld by vibrating the wire while periodically changing the welding current as described above, but the frequency of vibration is about 0.25 to 0.35 Hz. On the other hand, in the present invention, the wire is vibrated at a higher frequency of 1 to 20 Hz than in the secondary method. At this time, during the period when the periodically changing welding current is at a high value, the wire is
vibrate twice. The vibration of the wire does not need to be synchronized with the change in welding conditions and can be performed independently. Further, high-speed vibration of the wire can be easily obtained by vibrating the tip within the welding torch with a motor or the like, but it is also possible to vibrate the entire welding torch. The welding current changes at about 0.5 to 0.7 Hz as in the conventional method, and this is obtained by periodically changing the wire feeding speed.

Figure 3 shows an example of the change in welding current, where the welding current changes in a rectangular shape between 10M and 25M, the high current period TH is 0.5 seconds, and the low current period TL is 1 second. It is. In this example, the wire is vibrated at least once every 0.5 vibrations. As mentioned above, when the wire is vibrated at a frequency higher than IHz, the period during which the welding current is at a high value is usually a maximum of 1 second, and the wire must be vibrated at least once during this period. This is because high current areas and low current areas are mixed within the vibration range, making the state of melting inconsistent and the amount of welding unbalanced, making it impossible to form a good solution.

Further, the reason why the welding material is vibrated at a frequency of 20 Hz or less is because even if it is vibrated at a frequency exceeding that frequency, the effect will not be improved and the welding will become unstable. Next, this invention will be explained in more detail.

4 and 5 show horizontal butt MG according to the present invention.
An example of welding is shown. The joint is V-shaped with 4 gaps, wire frequency 2Hz, amplitude 6 ribs, welding fin flow maximum 25 melons L maximum 4.
10 skins, current change cycle 1.9 steps (Takawashi flow time 0.5 seconds,
Low current time 1. Akira). While moving the tip vibrating torch 10 in the direction d along the welding line, the tip of which is vibrated by a motor inside the torch, the wire 1 is vibrated so that the tips thereof draw a circle c. In the first layer welding, the wire 1 is vibrated with an amplitude larger than the gap G, so that the molten metal is completely bridged.

Also, on the rear side (the side where the molten pool 7 is) of the circular trajectory c drawn by the wire 1, the arc flies toward the surface of the base material on the molten pool 7, but as time passes, the arc moves toward the front side (the side where the wire is traveling). The arc acts to pull the molten metal forward, and the molten metal is pushed out to the opposite side by the force of the arc, so the molten pool 7 has good followability, resulting in a dead wave. Bead formation is easy. Therefore, even if the movement of the welding torch 10 is somewhat discontinuous or uneven, a good grade 6 can be obtained. Further, since the root surface 8 is melted during the period of high current and the wire 1 is vibrated during this period, defects such as poor fusion do not occur. During the low current period, the formed molten pool is not heated unnecessarily and is solidified into a flat bead, thereby preventing the occurrence of weld defects in subsequent layers. Also, in the melting of the second and subsequent layers, the molten metal is agitated by the vibration of the wire during the high current period, spread out, and solidified during the next low current period.

A flat bead is easily formed and a defect-free weld can be obtained. Similarly, a good weld can be obtained even in the case of downward welding or vertical welding.

In these cases, the molten metal tends to drip, so if the tip of the wire 1 vibrates in a circular motion, the arc will jump back onto the molten pool in the latter half of the trajectory in the direction of welding progress, causing unnecessary damage. to reduce the viscosity of the molten metal,
There is a risk that it will become more likely to sag and welding will not be possible. Therefore, it is best to weld by vibrating the wire linearly from side to side to avoid overheating the molten pool. As described in detail above, in the present invention, the wire is vibrated at least once during a period in which the welding current is at a high speed and at a high value.

As a result, the molten metal is agitated and spread by the vibration of the wire, so that even if the tip is wide, a bridge can be easily formed and a flat bead can be obtained. Furthermore, even in the case of horizontal butt welding, the arc pushes out the molten metal and a good rhombus peed can be obtained. Brief Explanation of Drawings Figures 1 and 2 respectively show the state of the bead bound by the subordinate welding method. It is a sectional view of a welded part.

FIG. 3 is a diagram showing changes in welding current in this invention. 4 and 5 show horizontal butt welding to which the present invention is applied, respectively. FIG. 4 is a perspective view showing a welding operation state, and FIG. 5 is a sectional view of a welded part. 1... wire, 3, 4...
Base material, 5...Welding metal cap, 6...Bead, 7
...... Molten pool, 8... Root surface, 9...
・・Uranami bead, 10・・・・・・Chip vibrating torch.

Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1 In semi-automatic or automatic arc welding in which the welding current is changed periodically and the wire is vibrated across the welding line, the frequency of the wire is 1 to 20 Hz and the welding current is a high value. A consumable electrode arc welding method characterized in that the wire is vibrated at least once during a period of time.