JPH1128571A - Torch nozzle for underwater welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably form a wide gas phase region without using a shield gas in a large quantity. SOLUTION: A dual nozzle structure is made of an inner cylinder 2, which throttles an inner diameter and supplies a shield gas of a small flow rate, and an outer cylinder 3, which guides jet water 6 between itself and the inner cylinder. A trumpet shaped skirt 10 spreading at a spreading angle of 70-80 deg. is integrally arranged to a tip of the inner cylinder 2. The jet water 6 is caused to flow along an outer face of the skirt 10 so as to swallow up surrounding water, thus, a water curtain 6a can be formed with a small water curtain flow rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torch nozzle for underwater welding, in which, among the underwater welding methods performed by a wet method, a gas shield is used with a water curtain to perform welding.

[0002]

2. Description of the Related Art As underwater welding methods for repairing and remodeling marine structures and the like underwater, there are known a wet method in which welding is performed directly in water and a dry method in which water is removed from a welded portion. I have.

[0003] Among the above-mentioned wet methods, the coating arc welding method of welding directly in water using a welding rod with a specially devised coating has been widely put into practical use, and has achieved some results in Japan. .

[0004] However, there are problems that the body is unstable under the environment of underwater, and that the welding itself requires advanced technology, and that the welded portion is more likely to generate blowholes than in the atmosphere. In recent years, of the wet method,
Researches on a water curtain type in which the vicinity of the welded portion is covered with a water curtain and a wire brush type in which the portion is covered with a wire brush are being advanced.

The underwater welding method of the water curtain type includes an inner cylinder 2 through which a welding wire 1 is passed at the center, and a gap between the outer periphery of the inner cylinder 2 as shown in FIG. As a double nozzle structure composed of the outer cylinder 3 disposed, a welding torch nozzle 5 having a trumpet-shaped jet port 4 at the tip of the inner cylinder 2 and the outer cylinder 3 is used. The jet water 6 is discharged from the jet port 4 at high speed to form a water curtain around the torch nozzle, and the water inside and outside the torch nozzle is cut off by the water curtain. At the same time, a suction action occurs in a radially outward direction from immediately below the torch nozzle in a narrow portion between the tip of the jet port 4 and the surface of the base material 8, and when the shield gas 7 is fed through the inner cylinder 2 in this state, the jet water 6
A stable gas phase region (cavity) 9 is formed immediately below the torch nozzle by the blocking action, suction action and crushing action of the scattered gas bubbles, and welding is performed in this gas atmosphere. 1a shows an arc.

In the water curtain type underwater welding method, it is known that the flow rate of the water curtain and the flow rate of the shielding gas 7 greatly affect the size and stability of the gas phase region 9 to be formed. Further, according to the relationship between the shield gas flow rate and the shape of the gas phase region, the spread angle of the jet port 4 is 40 to 60 °.
Is most effective.

FIGS. 8A, 8B, 9A, 9B, 10A, and 10B show three typical gas phase regions 9 formed.
In FIGS. 8A and 8B, a gas phase region 9 in which the inside of the jet water 6 is dry without any reverse flow into the inside of the jet water 6 is formed. 9 (a)
In (b), a reverse flow into the inside of the jet water 6 occurs partially, and in FIG. 10 (a) and (b), the inflow of the jet water 6 into the inside occurs over the entire circumference. It is.

[0008]

[0008] However, FIG.
(B) In the embodiment shown in (b), the gas phase region 9 is stable, but the distance between the jet port 4 and the base material 8 is as small as about 0 to 4 mm. There is a problem that a wide gas phase region 9 cannot be formed unless the diameter of the jet port 4 is increased, and in the case of the form shown in FIGS. Is large, 4 to 6 mm, and a gas phase region 9 wider than the case of FIGS. 8A and 8B is formed, but there is a problem that a stable state cannot be maintained uniformly over the entire circumference. Furthermore, FIG. 10 (a) (b)
In the case of the embodiment shown in FIG. 1, the distance between the jet port 4 and the base material 8 can be further increased to 6 to 18 mm, and a wider gas phase region 9 can be formed. A large amount of shielding gas 7 to balance with external pressure
There is a problem that requires.

In underwater welding, if the gas phase region 9 is narrow, the weld is quenched and the joint characteristics are affected. Therefore, the formation of a wide gas phase region 9 is an important issue.

Accordingly, an object of the present invention is to provide a torch nozzle for underwater welding capable of stably forming a wide gas phase region without using a large amount of shielding gas.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an inner cylinder in which a welding wire is passed through a central portion, and an outer cylinder which is arranged with a gap around the outer periphery of the inner cylinder. With a double nozzle structure to supply the shielding gas to the inside of the inner cylinder, and to guide the jet water between the inner cylinder and the outer cylinder, and at the tip of the inner cylinder, A skirt that spreads in a trumpet shape at a required angle so as to spread out is provided integrally.

The jet water discharged along the outer surface of the skirt involves the surrounding water, so that a water curtain is effectively formed, whereby the distance between the skirt and the base material can be increased. A wide gas phase region is formed.

[0013] In addition, by adopting a configuration in which the inner diameter of the inner cylinder is 12 to 15 mm and the spread angle of the skirt is 70 to 80 °, a stable gas phase region can be formed with a small flow rate of the shielding gas.

Further, by making the inner surface of the skirt a curved surface, not only can the gas phase region be made wider, but also the radiant heat of the arc light can be efficiently guided to the periphery of the weld.
Quenching after welding can be more effectively prevented.

[0015]

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

FIG. 1 shows an embodiment of the present invention, in which an inner cylinder 2 through which a welding wire 1 is passed is provided at the center.
An outer cylinder (3) arranged at the outer peripheral portion of the inner cylinder (2) with a gap provided between the inner cylinder (2) and the outer cylinder (3); A skirt 1 that has a double nozzle structure for guiding the jet water 6 and that has a trumpet-like shape at the tip of the inner cylinder 2 so as to be divergent.
0 is a torch nozzle 11 for underwater welding having a configuration integrally provided.

The inner diameter of the inner cylinder 2 is adjusted so as to increase the flow rate of the shielding gas so as not to affect the shape of the weld bead.
To 15 mm, and the spread angle θ of the skirt 10 is 70 to
It is set in the range of 80 °.

In a state in which the torch nozzle 11 is arranged so as to face the underwater base material 8, the jet water 6 is guided between the inner cylinder 2 and the outer cylinder 3, and the jet water 6 is discharged along the outer surface of the skirt 10. Then, since the surrounding water is involved, the water curtain 6a can be formed by a small amount of water jet. Therefore, the distance between the tip of the skirt 10 and the base material 8 can be increased, and a wide gas phase region 9 can be formed. This makes it possible to prevent rapid cooling of the welded portion.

In the above, the inner diameter of the inner cylinder 2 is 12 to 15
mm, because the flow rate of the shielding gas 7 can be increased to such an extent that it does not affect the shape of the welding bead. Can be formed.

In the present invention, the spread angle θ of the skirt 10 is set to 70 to 80 °. This is based on the knowledge of the inventor of the present invention, and when it is in the range of 70 to 80 °, The distance between the tip of the skirt 10 and the base material 8 could be maximized, and a wide gas phase region 9 could be formed.
Incidentally, it is possible to form the gas phase region 9 having a diameter of at most about 1.5 times the tip diameter of the skirt 10.

Next, FIG. 2 shows another embodiment of the present invention, in which the inner surface of the skirt 10 has a curved surface 10a in the same configuration as that shown in FIG.

As shown in FIG. 2, when the curved surface 10a is formed on the inner surface of the skirt 10, the gas phase region 9 can be widened by that much, and the light of the arc 1a is further reduced.
Since the light is reflected at a and collected around the welded portion, the periphery of the welded portion can be efficiently heated by radiant heat. Therefore, it is possible to more effectively prevent preheating of the welded portion and rapid cooling after welding while performing underwater welding, and reduce welding defects.

[0023]

Next, the results of various experiments performed by the present inventors will be described.

FIG. 3 shows that the spread angle of the skirt 10 is 75 degrees.
°, the height of the nozzle (distance between the tip of the skirt 10 and the base material 8) is 7 mm, and the water curtain flow rate (l / min) is 10 (△), 13 (○), 15 (□). ) Indicates the relationship between the shield gas flow rate (l / min) and the diameter (mm) of the shield region (gas phase region 9) when the shield gas flow exceeds about 40. Regardless, it can be seen that the diameter of the shield region is stabilized.

FIG. 4 shows that the spread angle of the skirt 10 is 75 degrees.
°, nozzle height 7mm, shield gas flow rate (l / min
) Is 50, the relationship between the water curtain flow rate (l / min) and the diameter of the shield area (mm) is shown. When the water curtain flow rate is between about 8 and 17, almost no influence is exerted on the diameter of the shield area. You can see that it has no effect.

FIG. 5 shows the divergence angle of the skirt 10 at 45 ° (△) and 60 ° under the stable shield gas flow rate and water curtain flow rate shown in FIGS. 3 and 4, respectively.
This shows the relationship between the height of the nozzle and the diameter of the shield area, which was changed to (○) and 75 ° (□), when the angle was 75 ° and the nozzle height was in the range of 7 to 9 mm. It can be seen that the diameter of the shield region has a peak.

FIG. 6 shows that the spread angle of the skirt 10 is 75 degrees.
°, the height of the nozzle was 7 mm, and the pressure was 0.1 MPa under the stable water curtain flow rate shown in FIG.
a (□ mark), 0.4 MPa (ＭＰ mark), 0.6 MPa (△
Mark) and the shielding gas flow rate (l / min)
And the diameter of the shield region (mm). It can be seen that the diameter of the shield region is stabilized when the flow rate of the shield gas exceeds about 55 under any pressure.

As described above, by devising the angle of the skirt 10 and the inner diameter of the inner cylinder 2 for supplying the shielding gas, a sufficient nozzle height for performing welding can be ensured, and the diameter of the tip of the skirt 10 can be increased. Also, a wide range of shield region can be formed stably.

[0029]

As described above, according to the torch nozzle for underwater welding of the present invention, the following excellent effects are exhibited. (1) An inner cylinder through which a welding wire is passed in the center, and an outer cylinder arranged with a gap around the outer periphery of the inner cylinder so that a shielding gas is supplied inside the inner cylinder. Along with
A structure in which a jet nozzle is introduced between the inner cylinder and the outer cylinder to form a double nozzle structure, and a skirt is provided integrally at the end of the inner cylinder at a required angle so as to be divergent at a required angle. Since the jet water discharged along the outer surface of the skirt involves surrounding water, a water curtain can be formed with a small amount of water, and a wide gas phase region can be formed. Rapid cooling of the weld can be prevented. (2) The inner diameter of the inner cylinder is set to 12 to 15 mm and the divergence angle of the skirt is set to 70 to 80 °, so that the flow rate of the shield gas can be increased and the gas phase region can be stabilized by a small amount of the shield gas. Can be formed. (3) By making the inner surface of the skirt a curved surface, the gas phase region can be further widened and the radiant heat of the arc light can be easily collected around the welded portion, resulting in rapid cooling after welding. Can be suppressed more effectively, and welding defects can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a torch nozzle for underwater welding according to the present invention.

FIG. 2 is a schematic diagram showing another embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a shield gas flow rate and a diameter of a shield region.

FIG. 4 is a diagram showing a relationship between a water curtain flow rate and a diameter of a shield region.

FIG. 5 is a diagram illustrating a change in a shield area depending on a height of a nozzle.

FIG. 6 is a diagram showing a relationship between a shield gas flow rate under pressure and a diameter of a shield region.

FIG. 7 is a schematic view showing an example of a water curtain type underwater welding method.

FIGS. 8A and 8B show one form of a gas phase region, wherein FIG. 8A is a schematic side view, and FIG. 8B is a view taken in the direction of arrows AA in FIG.

9A and 9B show another form of the gas phase region, wherein FIG. 9A is a schematic side view, and FIG. 9B is a view taken in the direction of arrows BB in FIG. 9A.

FIG. 10 shows still another embodiment of the gas phase region.
(A) is a schematic side view, and (B) is a view in the direction of arrows CC in (A).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Welding wire 2 Inner cylinder 3 Outer cylinder 6 Jet water 7 Shielding gas 8 Base material 9 Gas phase region 10 Skirt 10a Curved surface

Claims (3)

[Claims] 1. An inner cylinder through which a welding wire is passed in a central portion, and an outer cylinder arranged with a gap around the outer periphery of the inner cylinder so as to supply a shielding gas to the inside of the inner cylinder. And a double nozzle structure that guides jet water between the inner cylinder and the outer cylinder, and a skirt that expands in a trumpet shape at a required angle so as to be divergent at the tip of the inner cylinder. An underwater welding torch nozzle characterized by having a configuration provided. 2. The torch nozzle for underwater welding according to claim 1, wherein the inner diameter of the inner cylinder is 12 to 15 mm and the spread angle of the skirt is 70 to 80 °. 3. The skirt according to claim 1, wherein the inner surface is a curved surface.
Or a torch nozzle for underwater welding according to 2.