JP2002210559A - Carbon dioxide butt welding method for sheet metal stock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a butt welding method by which the quality of sheet metals 1 is not deteriorated, the quality is stabilized and distortion is reduced. SOLUTION: When sheet metals 1 having a thickness of <=6 mm are butt- welded, a welding torch 2 is moved at a moving speed of 65 cm/min, the length of an arc is shortened as a buried arc, the welding torch 2 is oscillated with a frequency of 10 Hz in the direction orthogonal to a weld line S, distortion in the sheet metals 1 is reduced and also penetration beads are stably formed, the surface of weld beads 4 is flattened. Thus, by the butt-welding method, the quality of the sheet metals 1 is not deteriorated, the quality is stabilized and distortion is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butt-welding method for butt-welding a large thin plate by carbon dioxide welding.

[0002]

2. Description of the Related Art In cruise ships, car carriers and the like, the hull is formed by butt welding (carbon dioxide welding) a number of thin plates. In such a ship, since it is required to lower the distortion (displacement) of the welded portion, various deformation reduction methods have been conventionally implemented. For example, a technique of performing uniform preheating, giving a strain such as tension in advance, or reducing the residual stress by performing machining on a bead immediately after welding has been implemented. It has also been considered that distortion is suppressed to a low level by employing laser welding.

[0003]

However, when carbon dioxide welding is performed using a large (for example, 9 mx 12 m) thin plate such as a passenger ship, the Uranami bead is not affected by any method. Problems such as stabilization and protrusion of a weld bead occur, and a method of stabilizing quality and reducing distortion has not been established at present. In addition, the use of laser welding can reduce distortion, but it increases costs and requires strict restrictions on groove accuracy.
It was not practical.

The present invention has been made in view of the above circumstances, and has as its object to provide a carbon dioxide gas butt welding method capable of stabilizing quality and reducing distortion.

[0005]

In order to achieve the above object, a carbon dioxide butt welding method according to the present invention is characterized in that when performing butt welding of a sheet material by carbon dioxide welding, a welding torch is welded at a speed exceeding 60 cm / min. The method is characterized in that the welding torch is oscillated in a direction crossing the welding line at a frequency of 8 Hz to 40 Hz while being moved along the line.

According to the carbon dioxide butt welding method of the present invention for attaining the above object, when performing butt welding of a thin plate by carbon dioxide welding, a welding torch is formed along a welding line at a speed exceeding 60 cm / min. The method is characterized in that the welding torch is oscillated in a direction intersecting the welding line at a frequency of 8 Hz to 40 Hz while moving in a state of a buried arc.

The heat input is set to less than 12 J / cm. The thickness of the sheet material is 6 mm or less. Further, the welding torch is moved along the welding line at a speed of 65 cm / min, and the welding torch is oscillated at a frequency of 10 Hz in a direction intersecting the welding line. Further, an aggregate for reducing distortion at a welded portion is attached to the back side of the thin plate material in advance. Further, the welding portion is cooled by gas from the front side behind the welding torch.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method for moving a welding torch along a welding line at a speed exceeding 60 cm / min.
The welding torch was oscillated in a direction crossing the welding line at a frequency of 40 Hz from z to reduce the heat input to less than 12 J / cm. It is known that shrinkage (lateral shrinkage, vertical shrinkage force) in a welded portion increases in proportion to heat input, and that by reducing heat input, shrinkage of the welded portion, that is, distortion, is reduced. Heat input Q
(J / cm): Q = current (A) × voltage (V) / velocity (cm / min), and increases according to current (A) and voltage (V),
It decreases according to the speed (cm / min).

Accordingly, in this embodiment, the welding speed (cm
/ min) to be more than 60cm / min and heat input Q (J /
cm) is kept low to reduce distortion. At this time, simply increasing the welding speed (cm / min)
Insufficiency of penetration causes instability of the formation of a penetration bead. For this reason, the arc length is shortened as a buried arc,
The arc pressure is made to strongly hit the base material. This makes it possible to stabilize the formation of the backside bead. Also, simply increasing the welding speed (cm / min) as a buried arc will result in the formation of a convex weld bead on the surface and a decrease in quality. For this reason, the welding torch is oscillated at a frequency of 8 Hz to 40 Hz in a direction intersecting (perpendicular to) the welding line. Thereby, the surface of the weld bead can be flattened.

A specific embodiment will be described below with reference to the drawings. FIG. 1 illustrates the principle of implementing a carbon dioxide butt welding method according to an embodiment of the present invention, FIG. 2 shows the relationship between the amount of welding deformation and heat input, FIG. 3 shows the relationship between heat input and welding speed, FIG. Shows the relationship between the oscillation frequency and the welding speed.

As shown in FIG. 1, a thin plate 1 having a thickness of 6 mm or less (for example, 5 mm) is abutted, and a wire (consumable electrode) (not shown) is used from a welding torch 2 and shielded with carbon dioxide gas. The molten pool 3 is formed at the butted portion to join the thin plates 1 together. A weld bead 4 is formed at the joint. Reference numeral 34 in the drawing is a backing material.

At this time, the welding torch 2 is moved at a welding speed of 65 cm / min in the direction along the welding line S (direction of arrow A) at a welding speed of 65 cm / min to reduce the heat input, and at the same time, the welding torch 2 is moved to the welding line S
Oscillate at a frequency of 10 Hz in the direction perpendicular to the direction to disperse the arc heat. Then, the arc length is reduced as a buried arc.

As a result, the heat input Q (J / cm) is suppressed low, the distortion is reduced, the formation of the backside bead is stabilized, and the surface of the weld bead 4 is flattened and flattened. When the welding speed is 65 cm / min and the oscillation frequency is 10 Hz, the heat input Q (J / cm) is 10.5 J by setting the current (A) to 360 A to 370 A and the voltage (V) to 32 V by the buried arc. /cm
(Less than 12 J / cm).

As shown in FIG. 2, the heat input Q (J / cm) is 12
If it exceeds J / cm, the amount of welding deformation (mm) exceeds the limit value Tmm, and distortion cannot be suppressed. As shown in FIG. 3, when the welding speed is 60 cm / min and the heat input Q (J / cm) is at a current of 360 A to 370 A and a voltage of 32 V.
12J / cm, heat input Q when welding speed is 60cm / min or less
(J / cm) is 12 J / cm or more.

As shown in FIG. 4, the oscillation frequency is set to 8 Hz when the welding speed is 60 cm / min, and is set to 65 cm / m
10Hz at in. Oscillate frequency is changed up to 40Hz at 65cm / min or more. If the oscillation frequency is less than 8 Hz, the welding speed is too high with respect to the oscillation frequency, and the welding bead 4 is in a meandering state.

As described above, the welding torch 2 is set at 65 cm / min.
The welding torch 2 is moved at 10Hz
By oscillating at a frequency of and shortening the arc length as a buried arc, the heat input Q (J / cm) becomes less than 12 J / cm under the conditions of a current of 360 A to 370 A and a voltage of 32 V, and the distortion is reduced. In addition, the formation of the penetration bead is stabilized, and the surface of the weld bead 4 can be flattened and flattened. The upper limit of the welding speed is the upper limit of the welding speed in a normal welding operation, for example, 150 cm / min.

Therefore, when performing butt welding of the thin plate 1 having a plate thickness of 6 mm or less, the welding speed (cm / min) is set to 60 cm / min.
, The arc length is reduced as a buried arc, and the welding torch 2 is oscillated in a direction intersecting (perpendicular to) the welding line S at a frequency of 8 Hz to 40 Hz according to the welding speed, thereby reducing the distortion of the thin plate 1. It is possible to stabilize the formation of the back bead and to make the surface of the weld bead 4 flat. Therefore, it is possible to achieve high-speed welding, and it is not necessary to remove welding deformation such as rapid heating and cooling that causes quality deterioration.
Welding that stabilizes the quality of the thin plate 1 without deteriorating the quality and enables low distortion can be achieved. In addition, since carbon dioxide gas welding is used, butt welding can be performed without making the groove conditions strict.

Preferably, a gas such as air or an inert gas is injected into the welding bead 4 from the front side behind the welding torch 2 to cool the welding portion. Thereby, the thin plate 1
The temperature distribution between the (base metal) and the welded portion can be relaxed to further suppress the distortion.

The condition of the weld will be described with reference to FIG.
FIG. 5 (a) shows the condition of the welded portion where the welding was performed under the conditions of the method of the present embodiment described above, and FIG. 5 (b) shows, as a comparative example, the welding when the welding was performed under different conditions. The situation of the department is shown. 5 (a) and 5 (b), the appearance of the weld is good.

In the case of the comparative example shown in FIG. 5 (b), the thin plate 1 having a thickness of 6 mm or less (for example, 5 mm) is butted and the welding torch 2 is moved along the welding line S as welding conditions, as in the above-described embodiment. Butt welding is performed by moving the welding torch 2 in a direction perpendicular to the welding line S at a frequency of 2 Hz at a welding speed of 50 cm / min. The current (A)
At 350 A, the voltage (V) is 36 V. The heat input Q (J / cm) is about 16 J / cm. By oscillating at a frequency of 2 Hz at a welding speed of 50 cm / min, the heat input Q (J / cm) becomes approximately 16 J / cm, and the distortion is reduced as shown in FIG. At the same time, the formation of the penetration bead is stable, the surface of the weld bead 4 is flattened and can be flattened, and the appearance of the welded portion is improved.

On the other hand, even when welding is performed under the conditions of the method of this embodiment, as shown in FIG. 5 (a), it can be seen that the appearance of the weld is good as in the comparative example. That is, even in the case of the method of the present embodiment, in which the welding speed is higher than that of the comparative example, by specifying the conditions such as the oscillating rate, the distortion is reduced, the formation of the penetration bead is stabilized, and the welding bead 4 is formed. The surface is flattened and can be flattened, and the appearance of the welded portion is improved. Therefore, it is understood that welding with high efficiency and reduced distortion can be performed as compared with the comparative example.

FIG. 6 illustrates the principle of a state in which a carbon dioxide butt welding method according to another embodiment of the present invention is performed.
FIG. 7 shows the relationship between the position of the aggregate and the amount of deformation.

As shown in FIG. 6, an aggregate 11 is temporarily attached to the back side of the thin plate 1, and the butt welding of the thin plate 1 is performed by the above-described method after the aggregate 11 is temporarily attached. . As shown in FIG. 7, as the position of the aggregate 11 is closer to the welding line S, the amount of welding deformation is smaller, and it is preferable that the aggregate 11 be located behind the welding line S. Aggregate 11
Since the amount of welding deformation increases as the position from the welding line S increases, it is preferable to set the distance L from the welding line S to 100 mm or less to position the aggregate 11. Distance L
Exceeds 100 mm, the amount of welding deformation exceeds the limit G, the amount of distortion increases, and the meaning of providing the aggregate 11 is lost. When the aggregate 11 is positioned behind the welding line S (distance L = 0), the attachment of the aggregate 11 and the butt welding can be performed simultaneously.

By providing the aggregate 11 on the back surface, welding deformation can be prevented and welding distortion can be further suppressed. Moreover, the aggregate 11 can also serve as a reinforcing material, and the rigidity of the butt-welded structure of the thin plate 1 can be improved.

FIG. 8 shows a principle explanation of a state in which a carbon dioxide butt welding method according to still another embodiment of the present invention is performed. Note that the same members as those shown in FIG. 6 are denoted by the same reference numerals, and redundant description is omitted.

As shown in FIG. 8, an aggregate 11 is preliminarily attached to the front side of the thin plate 1, and after the aggregate 11 is temporarily attached, the butt welding of the thin plate 1 is performed by the above-described method. . As shown in FIG. 8, as the position of the aggregate 11 is closer to the welding line S, the amount of welding deformation is smaller, and the aggregate 11 can be located at a position closest to the welding line S at a position that does not hinder butt welding. preferable. Since the amount of welding deformation increases as the position of the aggregate 11 moves away from the welding line S, it is preferable to set the distance L from the welding line S to 100 mm or less to position the aggregate 11. Distance L is 100m
If it exceeds m, the amount of distortion increases and the meaning of providing the aggregate 11 is lost.

By providing the aggregate 11 on the surface, welding deformation can be prevented and welding distortion can be further suppressed. Further, the aggregate 11 can also serve as a reinforcing material, and the rigidity of the butt-welded thin plate 1 can be improved.

A welding apparatus for carrying out the above-described carbon dioxide butt welding method will be described with reference to FIGS.
9 is a side view showing the entire configuration of the welding apparatus, FIG. 10 is a view taken along line XX in FIG. 9, FIG. 11 is a perspective view of the cooler, FIG.
2 shows the front of the cooler. In the illustrated welding apparatus, an example of an apparatus applied to butt welding when the aggregate 11 is temporarily attached to the front side of the thin plate 1 shown in FIG. 8 is described as an example. For this reason, the same members as those shown in FIG. 8 are denoted by the same reference numerals.

As shown in FIGS. 9 and 10, a pair of restraining rollers 22 are provided on the gantry 21 with the welding line S interposed therebetween. The restraining rollers 22 roll on the surface of the thin plate 1 and By means of 22, it is moved at a predetermined speed in the direction of the welding line S. The gantry 21 is provided with a welding torch 2 located on the welding line S, and the welding torch 2 is oscillated in a direction orthogonal to the moving direction (the welding line S direction) by an oscillating means (not shown).

As shown in FIG. 10, a slide shaft 23 extending in the vertical direction is provided near the restraining roller 22 of the gantry 21. Both ends of a support shaft 24 extending in a direction perpendicular to the moving direction of the gantry 21 (the direction of the welding line S) are slidably supported on the slide shaft 23 in the vertical direction. Is biased to the side. An aggregate restraining roller (rib restraining roller) 26 is rotatably supported on the support shaft 24, and the rib restraining roller 26 includes a compression spring 25.
Is pressed against the aggregate 11 via the support shaft 24 by the spring force of (1) to restrain the aggregate 11.

A cooler 31 is provided on the rear side of the welding torch 2 in the moving direction of the gantry 21, and the cooler 31 is
2, a predetermined gap is kept between the thin plate 1 and the surface thereof. The compressed air is supplied to the cooler 31 from the cooling gas passage 30. In the figure, reference numeral 33 denotes a surface plate on which the thin plate 1 is placed, and reference numeral 34 denotes a backing material arranged on the back side of the butted portion. In addition, an inert gas such as argon can be ejected from the cooling gas passage 30. When an inert gas is ejected, it is possible to use both a cooling gas and a shielding gas for preventing oxidation. It is also possible to adopt a configuration in which the gas at the welding portion is sucked from the cooling gas flow path 30.

As shown in FIG. 9, the above-described constraint roller 2
2, welding torch 2, rib restraining roller 26 and cooler 31
Are provided in the moving direction of the gantry 22 in plural sets (two sets in the illustrated example). As the welding torch 2, one electrode or two electrodes can be applied as needed, and can be set as appropriate. When the aggregate 11 is not provided or when the aggregate 11 is provided on the back side, the support shaft 24 and the rib restraining roller 26 are omitted.

The cooler 31 will be described with reference to FIGS. The main body 36 provided with the adjustment roller 32 includes
Three sets of air nozzles 37 are provided. The air nozzles 37 of each set are provided to face each other with the welding line S interposed therebetween. The compressed air sent from the cooling gas nozzle 30 is distributed to the air nozzles 37 via the distribution means 38 and is sent all at once. Air is blown out from the air nozzle 37 toward the welding bead 4, and the temperature distribution between the thin plate 1 and the welded portion is relaxed.

In the welding apparatus having the above structure, the restraining rollers 22
As a result, the gantry 21 moves at a predetermined speed in the direction of the welding line S, the welding torch 2 is oscillated at a predetermined frequency by an oscillating means (not shown), and the butted portion is welded under predetermined welding conditions. Compressed air is injected from the air nozzle 37 to the welding bead 4 during welding, and the temperature distribution with the base material is reduced. During welding, the aggregate 11 is restrained by the rib restraining roller 26.

In the above-described welding apparatus, since the cooling air is blown from the front side of the welded portion by the cooler 31, the welding bead 4 can be directly cooled by the compressed air, and the heat input can be suppressed. Further, since no cooling water is used, water treatment is not required, and water does not enter the welding bead 4, the Uranami bead or the like in butt welding. Since no cooling water is used, the backing material 34 in the figure can be omitted when there is no risk of foreign matter or the like entering.

[0036]

According to the method of the present invention, the butt welding of thin sheets is performed by moving the welding torch along the welding line at a speed exceeding 60 cm / min when performing butt welding of the thin sheets by carbon dioxide welding. The welding torch is oscillated in the direction crossing the welding line at a frequency of 8 Hz to 40 Hz, so that heat input can be suppressed, thin plate distortion can be reduced, and formation of a backside bead can be stabilized. In addition, the surface of the weld bead can be flattened. As a result, high-speed welding can be achieved, and work for removing welding deformation, such as rapid heating and cooling, which causes quality deterioration, becomes unnecessary. Welding can be achieved.
In addition, since carbon dioxide gas welding is used, butt welding can be performed without making the groove conditions strict.

Further, in the carbon dioxide butt welding method for a thin plate material according to the present invention, when performing the butt welding of the thin plate material by the carbon dioxide gas welding, the welding torch is buried along the welding line at a speed exceeding 60 cm / min. At the same time, the welding torch is oscillated in the direction crossing the welding line at a frequency of 8 Hz to 40 Hz, so that heat input can be suppressed and thin plate distortion can be reduced, and formation of backside bead formation. It can stabilize and flatten the surface of the weld bead. As a result, high-speed welding can be achieved, and work for removing welding deformation, such as rapid heating and cooling, which causes quality deterioration, becomes unnecessary. Welding can be achieved. In addition, since carbon dioxide gas welding is used, butt welding can be performed without making the groove conditions strict.

Further, the method for butt welding a thin plate material with carbon dioxide gas according to the present invention moves the welding torch along the welding line at a speed of 65 cm / min and simultaneously causes the welding torch to cross the welding line at a frequency of 10 Hz. As a result, the heat input can be suppressed, the distortion of the thin plate can be reduced, the formation of the backside bead can be stabilized, and the surface of the weld bead can be flattened. As a result, high-speed welding can be achieved, and work for removing welding deformation, such as rapid heating and cooling, which causes quality deterioration, becomes unnecessary. Welding can be achieved.

Further, since an aggregate for reducing the distortion of the welded portion is attached in advance to the back side of the thin plate, the distortion of the thin plate can be further reduced, and the reinforcing member also serves as a structural material. be able to.

Further, since the welding portion is cooled by gas from the front side on the rear side of the welding torch, the welding bead can be directly cooled by gas, heat input can be suppressed, and cooling water can be reduced. No water treatment required

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a carbon dioxide butt welding method according to an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a welding deformation amount and heat input.

FIG. 3 is a graph showing a relationship between heat input and welding speed.

FIG. 4 is a graph showing a relationship between an oscillation frequency and a welding speed.

FIG. 5 is a photographic view for explaining the situation of a weld.

FIG. 6 illustrates the principle of a carbon dioxide butt welding method according to another embodiment of the present invention.

FIG. 7 is a graph showing the relationship between the position of the aggregate and the amount of deformation.

FIG. 8 is a diagram illustrating the principle of a carbon dioxide butt welding method according to still another embodiment of the present invention.

FIG. 9 is a side view showing the entire configuration of the welding device.

FIG. 10 is a view taken along line XX in FIG. 9;

FIG. 11 is a perspective view of a cooler.

FIG. 12 is a front view of the cooler.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 thin plate 2 welding torch 3 welding pond 4 welding bead 11 aggregate 21 gantry 22 restraining roller 23 sliding shaft 24 supporting shaft 25 compression spring 26 aggregate restraining roller (rib restraining roller) 30 cooling gas nozzle 31 cooler 32 adjusting roller 33 constant Board 34 Backing material S Welding line

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Wakiyama 1-1 Akunoura-cho, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries, Ltd. Nagasaki Shipyard (72) Inventor Eiji Higashi 1-1-1, Akunoura-cho, Nagasaki-shi, Nagasaki Mitsubishi F term in Nagasaki Shipyard, Heavy Industries, Ltd. (Reference) 4E001 AA03 BB09 CA01 CC04 DF04 EA03 4E081 AA08 BA36 CA10 DA05 DA47 DA63 EA51 YA01 YX02 YX11

Claims (7)

[Claims] When performing butt welding of a sheet material by carbon dioxide welding, a welding torch is moved along a welding line at a speed exceeding 60 cm / min, and at the same time, a welding torch is applied to the welding line at a frequency of 8 Hz to 40 Hz. A carbon dioxide butt welding method for a thin plate material, wherein the method oscillates in an intersecting direction. 2. When performing butt welding of a sheet material by carbon dioxide welding, the welding torch is moved along a welding line in a state of a buried arc at a speed exceeding 60 cm / min, and at the same time, welding at a frequency of 8 Hz to 40 Hz. A method of butt welding carbon dioxide gas to a thin plate material, wherein a torch is oscillated in a direction intersecting a welding line. 3. The method according to claim 1, wherein the heat input is less than 12 J / cm. 4. The method according to claim 1, wherein the thickness of the sheet material is 6 mm or less. 5. The welding torch according to claim 1, wherein the welding torch is moved along the welding line at a speed of 65 cm / min while simultaneously intersecting the welding torch at a frequency of 10 Hz. A carbon dioxide butt welding method for a thin plate material, characterized by being oscillated in a direction. 6. The thin sheet material according to claim 1, wherein an aggregate for reducing distortion at a welding portion is attached in advance to a back side of the thin sheet material. Carbon dioxide butt welding method. 7. The method according to claim 1, wherein the welding portion is cooled by a gas from the front side behind the advancing of the welding torch.