JPH0694067B2 - High-speed rotating arc fillet welding method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a high-speed rotating arc fillet welding method, and more particularly to equalizing and smoothing a weld bead.

[Conventional technology]

Conventionally, in fillet welding of an upright plate erected on a lower plate, the fillet is welded by advancing along the joint in a downward horizontal posture.

[Problems to be solved by the invention]

In fillet welding in the downward horizontal position as described above, under the influence of gravity, as shown in Fig. 12, a hanging bead with different vertical plate leg length l ₁ and lower plate leg length l ₂ is likely to occur, Depending on the conditions, there is a fundamental problem that undercuts are likely to occur on the standing plate, especially for the formation of small leg long beads by high speed welding, or conversely for the formation of large leg long beads by high current / low speed welding. There was a problem.

The present invention has been made to solve the above problems, and it is possible to increase the bead length of the bead for fillet welding, increase the speed, expand the range of the construction leg length, and smooth the bead. The object is to propose a rotary arc fillet welding method.

[Means for solving problems]

The high-speed rotating fillet welding method according to the present invention is a fillet welding performed by rotating the electrode nozzle concentrically to rotate the tip of the wire passing through the current-carrying chip to rotate the arc at high speed. range of the rotational speed of the arc, upright leg l ₁ and lower plate leg l ₂ ratio l ₁ / l ₂ is No rotational speed becomes maximum (HZ) that when the lower limit No (HZ), the upper limit 120 ( HZ), (b) the rotating diameter of the above arc is 1 mm to 6 mm, and (c) the rotating wire is a wire with a diameter of 0.8 mm to 1.6 mm, and is directed downward by gas shield arc welding or submerged arc welding. This is a welding method for performing horizontal fillet welding.

[Work]

In the present invention, since the molten pool is easily spread to the peripheral portion by rotating the arc at a high speed, drooping of the bead is prevented, the leg length is made equal, and the bead is smoothed to secure the necessary penetration.

〔Example〕

In the high-speed rotating arc fillet welding method of the present invention, the arc is a high-speed rotating arc, in the conventional fillet welding that does not rotate, the bead hangs under the influence of gravity to prevent it. This is because the bead is biased to the standing plate side to obtain a bead of equal leg length. For example, as a result of examining the bead deviation by narrow groove welding while rotating the arc at a welding current I = 300 A and a welding speed V = 22 cm / min, the deviation θ of the bead with respect to the horizontal plane is as shown in FIG.
In FIG. 1, 1 is a lower plate, 2 and 2a are standing plates, 3 is an electrode which rotates rightward or clockwise when viewed from above, and 4 is a bead. In the figure, beads 4 are formed when welding proceeds to the back side of the paper. As shown in the figure, a large difference is found in the deviation of the bead 4 depending on the rotating direction of the wire 3 and the welding advancing direction. When the wire 3 is rotating to the right, the bead 4 is located on the upper right side in the welding advancing direction. The deviation θ of the bead 4 is related to the arc rotation speed N,
The rotation speed N (HZ) is shown on the horizontal axis and the deviation θ is shown on the vertical axis, as shown in FIG. 2. Welding current I = 300 A, welding speed V = 22 c
At m / min, the arc rotation speed N is 7HZ (420 rotations /
Min), the bias θ becomes maximum.

Therefore, when the corners of the lower plate 1 and the standing plate 2 are welded while rotating the electrode 3 by the downward horizontal fillet welding shown in FIG. 3 of this rotary arc welding, the arc rotation that maximizes the deviation θ of the bead 4 is achieved. When the speed is No, it is easy to obtain a bead having a uniform leg length, and the bead shape for fillet welding can be improved. Table 1 shows the results of examining the rotation speed No of the arc that maximizes the deviation θ of the bead 4 by changing the welding current I and the welding speed V.

As is apparent from Table 1, this rotation speed No depends on the values of the welding current I and the welding speed V, and the rotation speed No tends to increase as the ratio V / I increases. Therefore, the rotation speed No depends on the welding current I and welding speed V used,
If the welding current I and the welding speed V are determined, the rotation speed No that maximizes the deviation θ of the bead 4 is determined.

To determine this rotation speed No, fillet welding is performed at the welding current I and welding speed V used, and the ratio l ₁ / l ₂ of the leg length l _{1 of the} standing plate 2 and the leg length l ₂ of the lower plate 1 is the maximum. It suffices to find the rotation speed Fig. 4 shows the relationship between the arc rotation speed and the leg length ratio l ₁ / l ₂ when the welding current I = 300 A and the welding speed V = 22 cm / min. As shown in the figure, the rotation speed under these welding conditions is shown. No is 7HZ
(420 rpm).

As described above, when the rotation speed of the arc approaches No (HZ), it is easy to obtain a bead having a uniform leg length.

Further, when the rotation speed of the arc is close to No (HZ), the bead shape becomes a convex bead having a convex height Δl as shown in FIG. Therefore, the relationship between the arc rotation speed N (HZ) and the height Δl of the convex portion shown in FIG. 5 was examined, and the result was as shown in FIG. In Fig. 6, the horizontal axis indicates the arc rotation speed N (HZ).
The vertical axis shows the ratio of the height Δl of the convex portion of the bead to the average value of the standing plate leg length l ₁ and the lower plate leg length l ₂ . As is apparent from the figure, the height Δl of the convex portion of the bead is minimized when the arc rotation speed N (HZ) is approximately 3 No (HZ) or higher. This is because the high-speed rotation of the arc makes it easier for the molten pool to spread to the periphery.

On the other hand, when the shape of the bead was examined, in the case where the number of revolutions of the arc was zero, that is, in the case of the conventional horizontal fillet welding, the bead was a finger-shaped bead with a narrow center and a narrow width as shown by the chain line in FIG.
Since the beads 4a are formed and the beads 4a become drooping beads, when the welding speed becomes high, for example, 80 cm / min, the beads become unnecessary beads, and fillet welding cannot be speeded up.

However, in the range of the arc rotation speed from No (HZ) to 3No (HZ), the height Δl of the bead protrusion becomes small and the leg length ratio l ₁ / l ₂ is improved as shown in Fig. 5. The bead shape is the flat bead 4b shown by the solid line in FIG. 7, and the penetration in the width direction, particularly in the standing plate side increases, and the substantial penetration increases.

Further, when the arc rotation speed is 3 No (HZ) or more, the high-speed rotation of the arc makes it easier for the molten pool to spread to the periphery, further flattening the bead shape, and reducing the width direction of the lower plate side and the vertical plate side. Penetration increases.

By increasing the penetration by setting the number of revolutions of the arc above No (HZ), it is possible to prevent the occurrence of defective beads even if the welding speed is, for example, about 140 cm / min, and speed up fillet welding. be able to. Therefore, the number of revolutions of the arc is set to No (HZ) or higher.

When the arc rotation speed N increases, the wire melting speed MR also increases in proportion to the rotation speed N, as shown in FIG. 8, for example. That is, fillet welding becomes highly efficient. Fig. 8 shows the results of investigating the change in the melting speed MR of the wire in MAG welding with a wire diameter of 1.2 mm and a welding current of 300 A, with the arc rotation diameter set to 6 mm and the arc rotation speed N varied.
In FIG. 8, the horizontal axis is the arc rotation speed N (HZ), and the vertical axis is the wire melting speed MR (g / min).

However, when the arc rotation speed N is increased, the spatter increases as shown in FIG. FIG. 9 shows the arc rotation speed N when welding is performed under the conditions shown in FIG.
Shows the relationship between (HZ) and spatter loss (g / min). As is apparent from the figure, when the arc rotation speed N exceeds 120 (HZ), the spatter loss rapidly increases to about 25 g / min, which makes welding work difficult. Therefore, the arc rotation speed N is 120 (H
Z) is the following.

On the other hand, the leg length ratio l ₁ / l ₂ varies depending on the rotating diameter D of the arc even if the welding current I and the welding speed V are constant.

For example, welding current I = 300 (A), welding speed V = 22 (cm /
Min.), The result of performing fillet welding by changing the rotating diameter D of the arc at the number of rotations 7 (HZ) is shown in FIG. 10th
In the figure, the horizontal axis is the arc rotation diameter D, and the vertical axis is D = 0, that is, the leg length ratio l ₁ / l ₂ obtained when the arc is not rotated.
The leg length ratio l ₁ / l ₂ is shown as 1.0. As is clear from the figure, the leg length ratio l ₁ / l ₂ is 1.0 when the rotation diameter D is in the range of 1 mm to 6 mm.
As described above, the leg length ratio can be improved.

The suitability of fillet welding is related not only to the leg length but also to the suitability of the penetration depth. As a result of examining the relationship between the rotation diameter D and the penetration depth, the horizontal axis represents the rotation diameter D (mm) and the vertical axis represents the vertical axis. Penetration depth P (m
m) is shown in FIG. 11, and the penetration depth P does not become too shallow when the rotation diameter D is 4 mm or less, and the penetration depth P becomes zero when the rotation diameter D becomes 8 mm. As a result,
When the rotating diameter D is in the range of 1 mm to 6 mm, an appropriate penetration depth can be obtained.

Therefore, during fillet welding, the rotating diameter of the arc was 1 mm to 6 mm.
In mm, by setting the arc rotation speed range to No to 120 (HZ), it is possible to form a bead with an equal leg length and good penetration as shown in Fig. 11, and also to smooth the bead. You can

Although the above-mentioned embodiment shows the case of performing the MAG welding with a wire diameter of 1.2 mm, the above welding method can be applied within a wire diameter range of 0.8 mm to 1.6 mm. Except for the wire diameter of 2.0 mm or more, if the wire diameter is 2.0 mm or more, the rigidity resistance of the wire increases and a high output rotation mechanism is required to rotate the wire at high speed, so it is practical for price. This is because it does not become. Further, the welding is not limited to MAG welding, but may be applied to CO ₂ welding, TIG welding, and SAW welding.

〔The invention's effect〕

As described above, according to the present invention, since fillet welding is performed by a high-speed rotating arc having a constant rotation speed range and a constant rotation diameter, it is possible to prevent sagging of the molten metal, and to obtain an equal leg length and a good penetration. The bead can be easily obtained and the bead can be smoothed.

Further, since the wire melting speed is increased by the high-speed rotation of the arc, the efficiency of fillet welding can be improved, and the speed of fillet welding can be increased, and the length of the small leg or the length of the large leg can be increased. Have.

[Brief description of drawings]

FIG. 1 is a bias state diagram showing the bias of the bead, FIG. 2 is a characteristic diagram of rotation speed and bias, FIG. 3 is a schematic configuration diagram of an embodiment of the present invention, and FIG. 4 is a rotation speed and leg length ratio l ₁ / l ₂ characteristic diagram, Fig. 5 is a cross-sectional view showing the bead shape, and Fig. 6 is the height of the bead protrusion with respect to the average value of the arc rotation speed N and the vertical plate leg length l ₁ and lower plate leg length l _2. Fig. 7 is an illustration of the bead shape, Fig. 8 is a characteristic diagram of arc rotation speed N and wire melting speed MR, and Fig. 9 is arc rotation speed N and spatula. Fig. 10 is a characteristic diagram of loss, Fig. 10 is a characteristic diagram of arc rotation diameter D and leg length ratio l ₁ / l ₂ , Fig. 11 is a characteristic diagram of arc rotation diameter D and penetration depth, and Fig. 12 is a conventional bead. It is sectional drawing which showed the shape. 1 ...... lower plate, 2 ...... upright plate, 3 ...... electrode, 4, 4a, 4b ...... beads, l ₁ ...... upright leg, l ₂ ...... lower plate leg.

Claims (1)

[Claims] 1. In fillet welding performed while rotating an arc at a high speed, the range of the rotation speed of the arc is as follows: the vertical leg length l ₁ and the lower plate leg length.
the lower limit when the rotational speed ratio l ₁ / l ₂ of l ₂ is maximum and No (HZ) No (HZ) , the the 120 (HZ) limit, and 6mm rotation diameter of the arc from 1 mm, the rotation A high-speed rotating arc fillet welding method characterized by performing downward horizontal fillet welding by gas shield arc welding or submerged arc welding with a wire diameter of 0.8 mm to 1.6 mm.