JP2001179456A - Gas shielded arc welding torch for narrow gap welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a stable shielded atmosphere with a shield gas cup inserted into a narrow gap. SOLUTION: A torch nozzle I is constituted so that a contact tip 5 is mounted to the lower end part of a torch main body 1, in which an electrode wire 4 is guided therein and a shield gas 3 is made to flow in the inside of the lower end side through a tip holder 6. A shield gas cup 8 is a flat rectangular shape and is mounted so that a tip holder 6 and the contact tip 5 are pierced through its center, the electrode wire 4 is arranged to the center part of a discharge mouth 9. A regulating piece 11 is protruded to the lower inside faces of longitudinal direction both ends of the shield gas cup 8 to face inward. A notch 13 is arranged by removing the front end part. When the shield gas cup 9 is inserted to a prescribed position of a narrow gap 21 and welding is performed, the shield gas flowing inside the shield gas cup 9 is regulated so as to concentrate near the electrode wire 4 by the regulating piece 11 and an arc pool 14 is covered with a shield gas 3 to form a stable shielded atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas shielded arc welding torch suitable for performing narrow groove welding.

[0002]

Conventional MAG to be used for butt welding of members to each other, MIG, CO ₂ welding torch used in the welding process, as shown in an example in FIG. 3, the electrode wire being fed by the feed roller a A cylindrical shield gas cup d is concentrically mounted on the outer peripheral portion of the torch nozzle c through which the b is inserted, and the welding torch is directed to a groove f between the members to be welded e arranged in abutting relationship. While discharging the shielding gas g so as to wrap the electrode wire b from the lower end of the shielding gas cup d, an arc h is generated from the tip of the electrode wire b to melt the electrode wire b, thereby performing the butt welding of the groove f. It is like that.

In the butt welding performed by the MAG, MIG, and CO ₂ welding methods as described above, if necessary welding strength and quality can be obtained by welding, the welding time and the amount of thermal deformation can be reduced. The groove f between the members to be welded e is preferably narrow.

[0004] However, the welding torch used in the conventional gas shielded arc welding described above has a large cross-sectional shape because the shield gas cup d has a cylindrical shape. When applying to the welding of the narrow groove j of the welding member i, the shield gas cup d cannot be inserted to a required position of the narrow groove j, and it becomes difficult to weld the bottom of the narrow groove j. There is a problem.

For this purpose, a welding torch having a flat shield gas cup k which can be inserted into a narrow groove as shown in FIGS.

[0006]

However, when a welding torch having a flat shielding gas cup k is used, the shielding gas cup k can be inserted into the narrow groove, and the narrow groove j can be inserted. We can do welding work,
The shielding gas is a flat shielding gas cup k
The gas shield performance is degraded, such as turbulence and offset of the shield range, and pore defects such as blow holes are more likely to occur due to the fact that the gas is released freely from the lower end opening of the There is a fear. In order to cope with such deterioration of the gas shield performance, an after-shield gas discharge device must be provided at the tip of the torch to perform double shield construction in which a shield is formed by the after-shield gas. Accordingly, the device becomes complicated and the amount of shielding gas consumed increases, so that it has been desired to form a more stable gas shield atmosphere.

Therefore, an object of the present invention is to provide a gas shielded arc welding torch capable of performing narrow groove welding under a more stable shield atmosphere.

[0008]

According to the present invention, in order to solve the above-mentioned problems, a shield gas cup for discharging a shield gas has a width dimension of an inner surface slightly smaller than an outer diameter of a contact tip through which an electrode wire passes. As a flattened shape, the torch body having a contact tip at the lower part is passed through the center position of the flattened shielding gas cup, and the shield gas cup is inserted into both longitudinal ends of the shielding gas cup. Rectifying pieces with a width smaller than the width of the inner surface of the fin are installed facing each other so that the tip faces the center, and the shield gas that flows downward from above in the shield gas cup is laminarized by the two rectifying pieces. The configuration is such that the flow can be concentrated near the electrode wire.

Since the shielding gas cup has a flat shape, the bottom of the narrow groove can be welded without any problem by inserting it to a required position of the narrow groove by the thick member to be welded. At this time, the shielding gas released from the lower end of the shielding gas cup is laminarized by the rectifying piece and flows intensively near the electrode wires, so that the arc gas is efficiently covered by the shielding gas. Thus, welding can be performed in a stable shield atmosphere.

Further, if a notch is provided at the lower end of the shield gas cup in the entire range excluding one end in the longitudinal direction so as to correspond to the height of the weld metal to be built up during welding, the cut-off side advances. By performing the welding operation on the rear side in the direction, the molten metal portion which is built up as a bead at the time of welding can be covered under a uniform gas pressure to form a stable shield atmosphere.

Further, by adopting a structure in which a ceramic coating is applied to the rectifying piece and the contact tip, it is possible to prevent fumes, spatters and the like from adhering to the rectifying piece and the contact tip.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 (a), 1 (b) and 1 (c) show an embodiment of a gas shielded arc welding torch for narrow groove welding according to the present invention, in which a passage for an electrode wire 4 is provided at the axial center. The torch main body 1 has a flow path 1a for the shield gas 3 at the lower end and an inlet 2 for the shield gas 3 at the side, and has a flow path 6a for the shield gas 3 at the axial center. The tip holder 6 is attached, and the contact tip 5 is attached to the tip of the tip holder 6.
And the chip holder 6 are flattened so that the cross-sectional shape thereof is rectangular, the width of the chip holder 6 is made to correspond to the outer diameter of the contact chip 5, and a shaft is attached to the side of the chip holder 6. The flow path 6 of the shielding gas 3 at the core
is provided so that the shielding gas 3 entered from the inlet 2 passes through the flow path 1a in the torch main body 1 and the flow path 6a of the chip holder 6 and flows out of the gas outlet 7 to the outside. Then, the torch nozzle I is formed so that the electrode wire 4 is projected through the contact tip 5 by a required amount. An electrically insulating material (not shown) is provided and mounted on the outer peripheral portion of the chip holder 6, and no welding current flows on the side of the shield gas cup 8 fitted outside. There is.

On the other hand, the shield gas cup 8 for discharging the shield gas 3 flowing out from the gas outlet 7 provided on the side of the chip holder 6 from the discharge port 9 at the front end (lower end) is provided with the torch main body. 1 and a flat rectangular shape according to the flat shape of the chip holder 6, and the flat thickness of the shield gas cup 8 in the width direction is slightly tapered so that the tip becomes thin. The shield gas cup 8 having such a configuration is fitted to the outside of the torch main body 1 of the torch nozzle I and the tip holder 6 so that the longitudinal direction is the front-rear direction, and The torch nozzle I is positioned so as to penetrate, and the mounting portion 10 projecting above the shield gas cup 8 is attached to the torch main body 1.
The electrode wire 4 is detachably attached to the torch main body 1 along the tip of the shield gas cup 8.
So that it is arranged at the center position. Further, a cylindrical rectifying piece (gas diffuser) having a diameter slightly smaller than the inner dimension in the width direction of the shield gas cup 8 and a required length is provided on the lower inner side surface at both ends in the front-rear direction which is the longitudinal direction of the shield gas cup 8. ) 11 is arranged such that the tip end faces inward and approaches the contact chip 5, and is attached to the shielding gas cup 8 by bolts 12, and the shielding gas 3 that has exited into the shielding gas cup 8 from the gas outlet 7.
Is passed through a gas flow path formed between the contact tip 5 and the rectifying piece 11, thereby limiting the range in which the shielding gas 3 is directly blown to the arc pool 14, and restricting the flow velocity to form a laminar flow. The laminarized shield gas 3 can be made to flow intensively near the electrode wire 4.

The discharge port 9 at the lower end of the shield gas cup 8 is provided at the lower end edge except for the front end in the longitudinal direction at the height of the weld metal 15 which is built up as a bead behind the arc pool 14 during welding. The corresponding notch 13 is provided so that the deposited metal 15 is covered by the shield gas 3 discharged from the discharge port 9 under uniform gas pressure during welding.

Further, a U-shaped cooling water flow path 16 having both ends opened at the upper end surface of the shield gas cup 8 is provided at an upper position of both ends in the longitudinal direction in the upper part of the shield gas cup 8.
And a cooling water supply pipe 18 for guiding cooling water 17 from an upper cooling water supply unit (not shown) is connected to one end of each cooling water flow path 16, and an upper discharge (not shown) is connected to the other end. A cooling water discharge pipe 19 for discharging the cooling water 17 is connected to the section, and the shield gas cup 8 can be cooled by flowing the cooling water 17 through each of the cooling water passages 16.

The shield gas cup 8 in the present embodiment is made of copper and has a side wall having a thickness of 1.5 mm. This is because if the thickness is 1.5 mm, the welding can be performed with the used welding current value of 1000 Amp or more in combination with the effect of water cooling. The inner dimensions of the shield gas cup 8 are as follows: a width W of 0.8 to 1.2 cm and a length L.
Is in the range of 6 to 12 cm, and the cross-sectional area is 4.8 to 1
4.4 cm ^2, preferably made to be 7～14Cm ^2, further height as 3.5～6.5Cm, volume 2
It is set to be 0 to 50 cm ³ . In the above,
As long as the width W of the shield gas cup 8 is aimed at narrow groove welding, the narrower is better, but the upper limit is set at 1.2 cm.
If the width W exceeds 1.2 cm, the groove volume becomes large, which is uneconomical. In addition, length L is 6-12cm
The reason is that in the narrow groove welding, a welding current condition of 600 to 1200 Amp level is used irrespective of the diameter of the electrode wire 4, but in this case, the encapsulation range of the arc pool 14 size is appropriately 6 to 12 cm level. Because it is. Further, the sectional area of the shield gas cup 8 is set to 4.8 to 14.4.
The reason for setting cm ² is that if it is smaller than 4.8 cm ² , the encapsulation area of the molten pool also becomes proportionally small, and the welding current value must be limited to a small value.
This is because the enclosing range of the molten pool exceeding cm ² is excessively used as the narrow groove welding current condition and is not used. The reason why the height is set to 3.5 to 6.5 cm is that if the height is smaller than 3.5 cm, the shield gas 3 is uniformly diffused in the shield gas cup 8 to prevent turbulent discharge. On the other hand, the maximum value of the height is not strict, but if it exceeds 6.5 cm, the volume and weight of the welding torch itself will be increased, and this is not technically feasible. This is because it is considered necessary. Therefore, the required volume of the shield gas cup 8 is set to 20 to 5 in consideration of the cross-sectional area and height of the shield cup 8 described above.
0 cm ² . The flow rate of the shielding gas 3 is
8-12 LPM / at a cylinder pressure of 2-4 kgf / cm ²
cm ² . If the flow rate of the shield gas 3 is less than 8 LPM / cm ² , the shield atmosphere may be oxidized, and a defect may be generated due to a surrounding wind condition. ,
This is because a gas flow rate exceeding 12 LPM / cm ² is uneconomical. Further, the cross-sectional area of the two rectifying pieces 11 is set to 40 to 50% of the cross-sectional area of the shielding gas cup 8 because the laminar flow of the shielding gas is large enough to restrict the gas flow rate and make the laminar flow. This is because the concentration discharge of the gas and the concentrated encapsulation of the gas at the arc point can be greatly improved.

Further, the rectifying piece 11 and the contact tip 5 are coated with a ceramic,
During welding, fumes and spatters are prevented from adhering.

Reference numeral 20 denotes an insulating member, 21 denotes a narrow groove formed between the thick members 22 to be welded, and 23 denotes a backing metal.

When welding the narrow groove 21 between the members 22 to be welded, first, the tip of the gas shield arc welding torch with the shield gas cup 8 having a flat shape is inserted to a required position of the narrow groove 21. After placing the tip of the electrode wire 4 near the bottom of the narrow groove 21, welding is started,
Welding is performed by moving the notch 13 side to the rear side in the traveling direction. The shield gas 3 flowing downward from above in the shield gas cup 8 is
As a result, the flow is laminarized by the rectification, and the flow is concentrated and flown in the vicinity of the electrode wire 4, and is discharged so as to efficiently cover the arc pool 14. The bottom will be welded. At this time, since the notch 13 is provided in the discharge port 9 of the shield gas cup 8, it does not come into contact with the bead formed as the welding operation proceeds, and the welding gas 15 is formed by the shield gas 3. Can be encapsulated under uniform gas pressure.

When the bottom of the member 22 to be welded in the narrow groove 21 is welded, the welding position is sequentially moved upward with the progress of the welding operation. However, as shown in FIG. Becomes the upper part of the narrow groove 21, and if the width of the groove becomes wide and there is a risk of entraining the air,
Baffle plate 2 that rises to the required height in the vertical direction on the upper side of 2
4 is temporarily provided along the edge of the narrow groove 21 so that the welding is continued under a stable shield atmosphere without entraining air, similarly to the welding of the lower part in the narrow groove 21. Become.

As described above, since a stable shield atmosphere can be always formed in the narrow groove 21, the narrow groove welding can be performed in a state where the gas shielding performance is not likely to be deteriorated.

It should be noted that the present invention is not limited to the above embodiment. In FIG. 2, the baffle plate 24 for preventing the shield gas 3 from blowing in the left-right direction is provided on the upper surface of each member 22 to be welded. However, it is needless to say that the shield gas cup 8 may be attached to the shield gas cup 8 and various other changes may be made without departing from the gist of the present invention.

[0024]

As described above, according to the gas shielded arc welding torch for narrow groove welding of the present invention, the shield gas cup for discharging the shielding gas is provided with a contact having an inner surface having a width dimension through which the electrode wire passes. As a flat shape slightly larger than the outer diameter of the tip, a torch body having a contact tip below is passed through the center of the flat shield gas cup, and both ends in the longitudinal direction in the shield gas cup A rectifying piece having a width smaller than a width dimension of an inner surface of the shield gas cup is attached to each other so that a tip thereof is directed to a center portion, and a shield gas flowing downward from above in the shield gas cup is attached to the shield gas cup. Since it is configured so that it can be laminarized by the rectifying piece and can be concentrated and flow near the electrode wire,
Since the shield gas cup can be inserted to a required position of the narrow groove and the narrow groove welding can be performed, the shield gas can be discharged from the shield gas cup in the vicinity of the electrode wire in a concentrated manner. The arc pool formed at the time of welding can be efficiently covered with the shielding gas, and a stable shielding atmosphere can be formed.At the lower end of the shielding gas cup, the entire area excluding one end in the longitudinal direction is welded. By forming a notch corresponding to the height of the weld metal to be built up, the molten metal portion of the bead formed as the welding operation progresses can be covered with the shielding gas under uniform gas pressure. The rectifying piece and the contact tip can be wrapped, and the rectifying piece and the contact tip are coated with ceramic. Tact chip, there is exhibited an excellent effect that fumes or sputtering can be prevented from adhering.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a gas shielded arc welding torch for narrow groove welding according to the present invention, in which (a) is a schematic front view, (b) is a schematic cut-away side view, and (c) is a bottom view. It is.

FIG. 2 is a schematic view showing an example of a state in which a narrow groove is being welded.

FIG. 3 is a schematic view showing an example of a conventional gas shielded arc welding torch.

FIG. 4 is a schematic view of a state in which a conventional gas shielded arc welding torch is applied to a narrow groove.

FIG. 5 shows an example of a conventionally proposed gas shielded arc welding torch in which a shielding gas cup has a flat shape, (a) is a schematic front view, and (b) is a partially cut-away schematic side view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Torch main body 3 Shield gas 4 Electrode wire 5 Contact tip 8 Shield gas cup 9 Discharge port 11 Rectifying piece 13 Notch 15 Weld metal

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4E001 AA03 BB06 DF06 LD06 LF02 LH02 LH06 MA04

Claims (3)

[Claims] 1. A shield gas cup for discharging a shield gas, wherein the shield gas cup has a flat shape such that a width dimension of an inner surface is slightly larger than an outer diameter of a contact tip through which an electrode wire passes. A rectifying piece having a width smaller than the width dimension of the inner surface of the shield gas cup is provided at the center position so that a torch main body having a contact tip at a lower portion is passed therethrough, and a widthwise dimension of an inner surface of the shield gas cup is provided at both ends in the longitudinal direction in the shield gas cup. Are installed facing each other so that they face the center, and the shield gas flowing downward from above in the shield gas cup is made laminar by the two rectifying pieces so that the shield gas can be concentrated and flow near the electrode wire. A gas shielded arc welding torch for narrow groove welding, comprising: 2. The narrow groove welding according to claim 1, wherein a notch is provided at a lower end of the shielding gas cup in a manner corresponding to a height of a weld metal to be built up at the time of welding, except for one end in a longitudinal direction. For gas shielded arc welding torch. 3. The gas shield arc welding torch for narrow groove welding according to claim 1, wherein a ceramic coating is applied to the rectifying piece and the contact tip.