JPS6121751B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an arc welding device, and particularly to an arc welding device suitable for horizontal welding and vertical welding.

One type of conventional welding equipment is an arc welding equipment that uses a MIG welder. According to this method, a welding torch that protrudes a core wire for arc welding from its tip and blows out shielding gas is moved along a groove between two base materials to be welded, thereby welding the two base materials together. Can be welded to.

In the conventional welding apparatus, in the case of downward welding in which the groove extends substantially horizontally and opens upward, if the groove is relatively narrow, the tip of the welding torch is not vibrated; Beads of uniform thickness can be obtained without any weaving motion.

On the other hand, in the case of horizontal welding in which the groove extends almost horizontally and opens laterally, or vertical welding in which the groove extends in the vertical direction, even if the groove is relatively narrow, uniform thickness can be achieved. In order to obtain a bead, it is necessary to vibrate the tip of the welding torch.

However, when vibrations are applied to the tip of the welding torch, vibrations also occur in the shielding gas flow ejected from the tip of the torch, causing air to be trapped in the shielding region at the tip of the gas flow. the result,
There are so-called cavities in welds, and the weld failure rate is 20%.
It was possible to reach even. Even if the ejection pressure of the shielding gas from the welding torch is simply increased, the above-mentioned air entrainment cannot be prevented, and good welding cannot be achieved by this alone.

SUMMARY OF THE INVENTION An object of the present invention is to provide an arc welding device that prevents cavities from entering welded parts even in horizontal welding and vertical welding.

According to the present invention, when the tip of a welding torch that is moved along a groove is vibrated, the shield area formed by the shielding gas ejected from the tip causes air to be entrained before and after the shield area. A pair of auxiliary shield regions are formed in the groove before and after the shield region, overlapping with the shield region and not vibrating, and by the auxiliary shield regions, the tip of the welding torch is The basic concept is to prevent air from being drawn into the shielding area by the shielding gas ejected from the shielding area.

In order to achieve this, the welding device according to the present invention supports a welding torch on a frame movable along the groove via a weaving device, and arranges the welding torch in the moving direction with the welding torch interposed therebetween, and each a pair of auxiliary nozzles located within the groove are fixedly supported on the frame, and a shielding gas outlet is formed by the shielding gas ejected from the tip of the welding torch by the operation of the weaving device. The main shield area is formed by the shield gas ejected from the auxiliary nozzle.
so that it overlaps both of the two auxiliary shield areas.
The welding torch is characterized in that vibrations are applied to the tip of the welding torch.

According to the present invention, the two auxiliary shield regions that overlap the vibrating main shield region in the front and rear portions move along the groove without vibrating, so that the auxiliary shield region itself To effectively prevent air entrainment in the front and rear parts of the main shield area which vibrate without causing air entrainment.

Furthermore, in the present invention, it is important that the shielding gas ejection ports of the two auxiliary nozzles forming the auxiliary shielding area are both located within the groove. That is, if the ejection port of at least one of the auxiliary nozzles is located outside the groove, the auxiliary shielding gas flow injected from the ejection port into the groove will be directed toward the inside of the groove. This is because the open edge of the tip causes some turbulence, which causes the auxiliary shielding gas flow to entrain air, which increases the incidence of cavities in the welded part. be.

The features of the present invention will become clearer from the following description of the illustrated embodiments.

In FIG. 1, a portion of an arc welding apparatus according to the present invention is indicated by the reference numeral 10.

In the illustrated example, the welding device 10 is installed to automatically perform horizontal butt welding of two base materials 12a and 12b. The thickness of the two base materials 12a, 12b to be welded together is, for example, 20 mm or more, and as shown in FIG. This can be done by using the backing member 14 that has been erected.
As clearly shown in FIG. 2, the groove 16 between the two base materials 12a and 12b has an approximately right triangular cross section, a root gap of 6 mm, a root face of 2 mm, and a groove angle of 30 degrees. Each is set. However, the shape and dimensions of the groove described above are merely examples, and the welding apparatus according to the present invention can be applied to groove welding of various groove shapes and dimensions.

The welding device 10 includes an automatic traveling device 20 that moves on a track 18 installed along the groove 16 in the direction in which the groove extends, and a weaver 22 that is disposed on the surface side of the base materials 12a and 12b. A welding torch 24 supported on the automatic traveling device 20, which is a frame movable via the welding torch 24, and a pair of auxiliary nozzles 16a,
26b.

The support shaft 28 of the weaver 22 is connected to the traveling device 20.
It is supported by an arm 30 extending from. The arm 32 of the weaver 22 holds the welding torch 24 via a torch holder 34 provided on the arm so that the tip of the torch is located within the groove 16. As is well known in the art, the weaver 22 swings the welding torch 24 in the direction indicated by reference numeral 36 in FIG. 1 on a plane that crosses the groove 16 in an open manner.

The automatic traveling device 20 has an L-shaped connecting fitting 38.
One side 40 is screwed to allow longitudinal adjustment of the side. The other side 42 of the metal fitting 38 is arranged along the groove 16, and a recess 44 is formed in the center of the other side to prevent interference with the welding torch 24. Said metal fitting 3
Two auxiliary nozzles 26a, 26 are provided on both sides of the recess 44 of No. 8 at a distance from the welding torch 24.
b is fixedly supported. Both auxiliary nozzles 26
Branch portions 48a and 48b of a gas pipe 46 extending from a shielding gas source are connected to the base portions a and 26b, respectively.

Both auxiliary nozzles 26a, 26b extend into the groove 16, as shown in FIGS. 2 and 3, and the tips of each auxiliary nozzle 26a, 26b have jets that open toward each other. Exit 50a, 50
Attributable to b. In order to adjust the direction of each spout 50a, 50b, each auxiliary nozzle 26 has a rotating part 52.
a, 52b are provided. This rotating part 52
Although it is possible to eliminate the need for a and 52b, it is preferable to provide the rotating portion in order to enable position adjustment of the two auxiliary shield areas described later. Moreover, the rotating part can be a universal joint part.

The welding torch 24 located between the pair of auxiliary nozzles 26 arranged in the extending direction of the groove 16 has a similar configuration to that of a welding torch of a conventional MIG welding machine. That is, as shown in FIG. 3, the tip of the welding torch 24 located within the groove 16 is blown out with shielding gas supplied via a conduit cable 54 connected to the base of the torch. A spout 56 is provided for this purpose, and the tip of a core wire 58 that is fed through the cable 54 protrudes from the center of the spout. This core wire 58 is connected to the base metals 12a and 1 as in the conventional MIG welding machine.
2b, an arc is generated and melted, and as the core wire 58 is melted, the core wire 58 is continuously supplied.

In the welding apparatus 10 according to the present invention, various shielding gases such as 100% carbon dioxide gas, 100% argon gas, or a mixed gas of carbon dioxide gas and argon gas are used as the gas ejected from each auxiliary nozzle 26a, 26b and the welding torch 24. In addition, the shielding gas flow rate from each auxiliary nozzle 26a, 26b is set to, for example, 7.5/min, and the shielding gas flow rate from the welding torch 24 is set to, for example, 30 to 30 min.
40/min.

In order to facilitate understanding of the relationship between each shield area formed by each auxiliary nozzle 26a, 26b and the shield gas from the welding torch 24, this relationship is shown in FIG. explain.

A spout 50a of one of the auxiliary nozzles 26a located on one side of the welding torch 24, that is, in the front, opens toward the tip of the torch 24 within the groove 16. Therefore, the auxiliary shielding gas ejected from the jetting port 50a forms an elliptical auxiliary shielding region 60a extending in the direction in which the groove 16 extends.

Moreover, on the other side of the welding torch 24, that is, on the rear side,
The auxiliary shielding gas ejected from the ejection port 50b of the other auxiliary nozzle 26b, which is arranged almost symmetrically with the auxiliary nozzle 26a, partially overlaps the shielding area 60a at the rear of the auxiliary shielding area 60a. 16 is formed.

Furthermore, when the central axis of the welding torch 24 is on a plane perpendicular to the surfaces of the base metals 12a, 12b, the main shielding gas ejected from the spout 56 of the welding torch 24 is transmitted to both the auxiliary shielding regions 60a and 60b. A circular main shield area 62 is formed approximately at the center of the overlapping area. When the welding torch 24 oscillates as indicated by the reference numeral 36 due to the operation of the weaver 22, the main shield area 62 vibrates as the jet nozzle 56 of the torch vibrates. However, due to this vibration, the front and rear portions of the shield area are damaged by both the auxiliary shield areas 60a and 60b.
The front part of the main shield area 62 always overlaps the auxiliary shield area 60a, and the rear part of the main shield area 62 always overlaps the auxiliary shield area 60b without departing from the auxiliary shield area 60b.
always overlap.

When the traveling device 20 travels on the track 18 by the operation of the traveling device 20, the tip of the welding torch 24, that is, the spout 56, is moved by the vibration motion provided by the weaver and by the traveling device 20. The combined movement with the linear movement along the extension direction of the groove 16 produces a zigzag movement, for example, in a weaving pattern of 40 times/min with a pitch of 15 mm, as shown at 64 in FIG. . However, due to the operation of the traveling device, the pair of auxiliary nozzles 26a and 26b are connected to the welding torch 2.
4, the main shield area 62 and the two auxiliary shield areas 6
The above-described overlapping relationship with 0a and 60b is maintained.

Therefore, two auxiliary shield areas 60a and 6
0b prevents air from being entrained in the front and rear portions of the main shield area 62 due to vibration. Furthermore, the auxiliary shield areas 60a, 60b
Both auxiliary nozzles 26a and 26b eject auxiliary shielding gas to form a
a and 50b are located within the groove 16. Therefore, the shielding gas flow ejected from the respective ejection ports 50a, 50b is not directly injected onto the edges 16a, 16b of the groove 16, and the edges do not cause turbulence that entrains air. .

As a result, the welded portion of the groove 16 can be reliably shielded from the air, thereby making it possible to perform good welding without cavities.

In the above description, the welding apparatus according to the present invention has been explained using an example of horizontal welding, but it can also be applied to vertical welding and even downward welding. Further, without overlapping both auxiliary shield areas with each other, one auxiliary shield area overlaps the front part of the main shield area, and the other auxiliary shield area overlaps the rear part of the main shield area, It is also possible for the two auxiliary shielding regions to be formed at a distance from each other. However, as described above, it is preferable to form both auxiliary shield regions so that they partially overlap each other in order to enhance the shielding effect.

According to the welding device according to the present invention, as described above, even when welding a relatively wide groove horizontally or vertically, it is possible to perform good welding without causing formation of cavities. ,especially,
It exhibits an excellent effect in forming the initial welding layer, that is, the first layer.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the welding device according to the present invention, FIG. 2 is a longitudinal sectional view showing the groove shown in FIG. 1, and FIG. 3 is a front view of the welding device shown in FIG. FIG. 2 is a perspective view of a portion of the device as viewed diagonally from below. 10: Welding device, 16: Bevel, 20: Frame (automatic traveling device), 22: Weaver, 24: Welding torch, 26a, 26b: Auxiliary nozzle, 50a,
50b: auxiliary nozzle outlet, 56: welding torch outlet, 58: core wire, 60a, 60b: auxiliary shield gas area, 62: main shield gas area.

Claims (1)

[Scope of Claims] 1. A frame movable in the direction of extension of a groove to be welded, a welding torch that projects a core wire for arc welding from its tip extending into the groove and spouts shielding gas; A weaving device that supports a welding torch on the frame and swings the welding torch to give vibrations within the groove to the tip of the welding torch, and a weaving device that moves the welding torch in the direction of extension of the groove, with the welding torch interposed therebetween. a pair of shielding gas auxiliary nozzles arranged in the welding torch, each fixedly supported by the frame and having a shielding gas outlet located in the groove; An arc welding device characterized in that the tip of the welding torch vibrates within a range in which a shielding area by the gas always at least partially overlaps both of two shielding areas by the shielding gas from the auxiliary nozzle. 2. The arc welding apparatus according to claim 1, wherein the shielding gas injection direction of the auxiliary nozzle is adjustable. 3. The arc welding apparatus according to claim 1, wherein the welding torch is oscillated on a plane that angularly crosses the groove.