JPH08309524A - Automatic welding method and device and welded structure - Google Patents

Abstract

PURPOSE: To provide a welding technique capable of executing welding with an optimum welding method and procedures in the case multilayer build-up welding in a three o'clock position by an automatic welding machine is executed at the time of connecting a square column and a square column by welding on installation site, etc. CONSTITUTION: A welding wire 8 is fed along the outside diameter of a roller 3 to a narrow groove torch 6 if a roller 4 exists below the axial line connecting the rollers 2, 3, 5 which are the wire feeding parts in a wire feeding unit 1 at the time of feeding the wire 8. The permanent set of downward bending is, therefore, added to the wire 8 and since the wire 8 emerges downward from a torch 6, the front end of the wire 8 is capable of aiming the angle part of rear surface of the groove 10. The execution of the welding of the rear surface of the groove 10 without inclining the torch 6 is thus possible. If the roller 4 exists upper than the axial line, the permanent set of upward bending is imparted to the wire 8 and the front end thereof is capable of aiming the angle part of the front surface of the groove 10. Since the continuous lamination of even an I type groove 10 is possible, the automatic welding is efficiently executable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic welding method and apparatus and a welded structure obtained by the automatic welding method, and more particularly to an automatic welding technique for a prism used in a steel frame of a building.

[0002]

2. Description of the Related Art In addition to shape steel, thick plate prisms are used for the steel frames of large buildings such as boiler steel frames, and in the field installation, the prisms are connected to each other by horizontal multi-layer welding in many cases. . Conventionally, this part is welded by manual welding or semi-automatic welding, but to improve the efficiency of welding work,
A welding method using an automatic welder has also been proposed (for example, Hitachi Zosen Giho Vol. 55 No. 3).

The shape of a prismatic weld groove joint (hereinafter, also referred to as a groove) may be that of a groove 10 'having a square cross section of a prism 9 as shown in FIG. Generally, in a thick plate such as the prism 9, the groove shape becomes large, the number of weld metal layers increases, and a lot of time is required for welding. There is also proposed a groove 10 having an I-shaped cross section, which has a groove shape parallel or nearly parallel as shown by 15, and has no groove angle.

In both of the groove shapes shown in FIGS. 14 and 15, as shown in FIG. 16, a MAG (Metal Active) is used by using a backing plate or a member that serves as a backing plate.
Gas) is often done by welding. FIG. 16 shows a state before the upper prism 9 is inserted into the lower prism 9. A backing plate 31 and a receiving backing plate 32 are inserted inside the lower prism 9, and a butt backing plate 34 is placed inside the upper prism 9.
Are installed at each factory. In the case of the prism 9 manufactured by welding the corner, irregularity is likely to occur in the vicinity of the corner due to the influence of welding strain, etc.
It is more convenient to dispose 1 on the straight portion and the butt backing metal 34 and the receiving backing metal 32 on the corners.

As shown in FIG. 16, when the L-shaped groove of the prism 9 is welded using a backing plate 32 or the like, as shown in FIG.
As shown in (a) or FIG. 18, a groove-shaped groove 10 '.
However, if the standard groove angle is, for example, 35 degrees or 37 degrees, the inside of the groove 10 'is wide, so that the welding torch angle can be selected as an appropriate angle for welding in the groove 10', and in particular, poor fusion occurs. A good weld can be relatively easily obtained even on the easy groove 10 ′ surface.

In this case, the welding metal is laminated as shown in FIG.
As shown in (a) or FIG. 18, the first layer is performed in one pass, but the second layer is increased to two passes, the third layer is increased to two passes or three passes, and the final layer is seven passes or eight passes. Next to
The total number of passes is 34 or 42, which is a considerable number of layers.

Therefore, by automating a work which requires a considerable work time in manual welding or the like, a considerable improvement in work efficiency can be obtained. However, FIG.
As shown in (a) and the laminated state of the groove 10 'in the third layer and thereafter, as shown in FIG. 18, the machining dimension tolerance of the groove shape such as the groove angle, the set dimension tolerance of the groove surface, the welding condition Since it is necessary to change the method of laminating the weld metal due to the difference in the shape of the welded layer due to the difference, it is difficult to automatically weld all the layers in succession.

On the other hand, when the automatic welding is applied to the I-shaped groove shape, the welding metal may be laminated in two passes / layer from the first layer to the last layer as shown in FIG. 17 (b). Since it is possible and there is no variation in the number of passes as in the case of the V-shaped groove 10 ', it is suitable for automatically welding all the laminated layers continuously.

However, when the groove shape is I-shaped, as shown in FIG. 19, since there is almost no groove angle, groove 1
Since the inside of 0 is narrow, the welding torch angle cannot be selected as an appropriate angle for welding in the groove 10, and the target direction of the wire 8 from the welding torch 6 cannot be directed to the surface of the groove 10.
Particularly in the case of a thick plate such as a prism 9, the welding torch 6 is inserted into the groove 10, so that the welding torch 6 is set substantially parallel to the surface of the groove 10 and the welding is performed while moving the parallel torch. Therefore, the aiming direction of the wire 8 from the welding torch 6 is substantially parallel to the surface of the groove 10, and
Penetration failure is likely to occur on the 0th surface.

Therefore, when the automatic welding is applied to the I-shaped groove shape, as shown in FIG. 15, the welding torch 6 is used to direct the wire 8 from the welding torch 6 to the groove 10 surface. There has been proposed a method of inclining the wire, and a method of increasing the welding current to obtain a predetermined penetration.

However, the method of tilting the welding torch 6 is particularly effective for thick plates such as prisms 9 in which the groove 10 is used.
As the inside becomes narrower, it is necessary to widen the groove width, which means that the number of laminated layers increases, and the square-shaped groove 10 'is formed.
Have no advantage over.

In addition, in the method of increasing the welding current, the welding condition range in which an appropriate laminated shape and penetration can be obtained and the allowable range of the setting position of the welding torch 6 are narrowed, and therefore, several tens of meters from the ground. The power source cable of the capacity that can supply a large current is laid at the local welding position which also becomes, and the prism 9 which is a can-making product manufactured with the can-making tolerance,
Since it is necessary to install a device capable of precisely setting the position of the welding torch 6, this method is not suitable for practical use.

On the other hand, in the welding procedure, as shown in the horizontal cross-sectional view of the prism 9 in FIG. 20, the linear rail 21 installed around the gap of the groove 10 (hatched portion) of the prism 9.
Welding head 1 with welding torch for guide devices such as
1 is mounted and welding is performed while the welding head 11 continuously moves in the circumferential direction of the prism. That is, the prism 9
With the welding start point at an arbitrary position on the predetermined one surface, the four passes of the prism 9 are continuously welded in the first pass counterclockwise or clockwise, and then the second pass is welded by folding back at the welding start point. The method of repeating is performed.

In addition to this, as shown in the cross-sectional view of the prism 9 in FIG. 21, a method of welding all the laminated layers on any one of the four faces of the prism 9 (see FIG. 21). The arrow A shown on the lower surface represents the welding sequence, and the upper surface represents a welding layer composed of four layers.) And the like are generally performed.

First, the prisms 9 are continuously connected as shown in FIG.
In the method of welding four surfaces or two or more surfaces, the welding head 1 having the welding torch 6 at the corner of the prism 9 is provided.
1 needs to rotate 90 degrees, but in this case, under the same welding conditions as the straight portion, if the amount of weld metal supplied while the welding head 11 rotates 90 degrees is too large, excess weld metal is laminated. The shape becomes defective, which causes troubles in continuous welding.

As a countermeasure against this, at the corner of the prism 9,
There are a method of increasing the welding speed, that is, a rotating speed to reduce the supply amount of the weld metal per unit time, a method of decreasing the supply amount of the weld metal without decreasing the welding speed, and a method of interrupting the welding.

However, in the method of increasing the welding speed at the corner portion, the welding speed needs to be several tens of times higher than that of the straight portion, so that the limit of the apparatus capacity and the stability of the laminated shape at a high speed are required. From the viewpoint, it is a method that is not suitable for practical use.
In addition, if it is necessary to restart welding from the corner for some reason, the welding speed immediately after the start of welding is several m / m.
It becomes a high speed running for a minute and a stable weld metal shape can not be obtained,
Repair by manual welding is required.

Further, in the method of reducing the supply amount of the weld metal without significantly reducing the welding speed, in the case of the welding method using a consumable electrode such as MAG welding, the supply amount of the weld metal depends on the current. Therefore, in order to reduce the supply amount of the weld metal, it is necessary to greatly reduce the electric current, which is likely to cause a defective laminated shape or a defective melting.

Further, as shown in FIG. 22, in the method of continuously welding the four or more surfaces of the prism 9 as described above, even if the welding conditions of the corners of the prism 9 are set well, the square cross-sectional shape Since the laminated shape becomes an arc shape at the corner part, the overlay welding is done by manual welding in order to finish it into a square cross-sectional shape after the completion of automatic welding, and it is efficient including the grinder finishing after welding. Welding work could not be done.

Next, as shown in FIG. 21, in the method of welding every one surface of the prism 9, the ceramic tab 22 is provided at the corner portion in order to prevent the weld metal from flowing into the adjacent surface. It is installed and the welding is performed while repeating the reciprocating movement of a welding head having a welding torch (not shown) in a plane including a corner portion for each arbitrary surface. In this method, the ceramic tab 22 of the corner portion is used. Welding defects are likely to occur in the part, and particularly, there are many welding defects at the welding start part and the end part. Further, in this method, the ceramic tab 2 at the corner is
Since 2 is installed in the groove, the shape of the welding torch is limited. That is, although the welding torch and the ceramic tab 22 can be used without interfering with the welding torch and the ceramic tab 22 in the square-shaped groove 10 'using a small torch having a circular cross-section, a thin, plate-shaped narrow groove torch is used. I-shaped narrow groove 1
At 0, the welding torch and the ceramic tab 22 interfere with each other at the corner, and therefore cannot be used.

[0021]

The above-mentioned prior art has the following problems. That is, when connecting the prisms 9 to each other by welding, such as when the prisms 9 are installed at the target site, when performing multi-layer welding in a horizontal position by an automatic welding machine, FIG. 14 and FIG. ,
In the case of having a V-shaped groove 10 'shown in FIG. 18, the difference in the welding laminated shape due to the machining dimension tolerance of the groove shape such as the groove angle, the set dimension tolerance of the groove surface, and the difference of welding conditions. It is difficult to automatically continuously weld all the laminated layers because it is necessary to change the method of laminating the weld metal.

When the shape of the groove 10 shown in FIGS. 15 and 19 is I-shaped, there is almost no groove angle, so the inside of the groove is narrow, and the welding torch angle is selected to an appropriate angle within the groove. Since it was not possible to aim the wire 8 from the welding torch 6 at an appropriate angle with respect to the groove surface, there was a problem that a melt-in defect was likely to occur on the groove surface.

As a countermeasure for the above-mentioned conventional technique, a welding torch 6 is used.
The welding torch 6 can be tilted by orienting the target direction of the wire 8 from the welding torch 6 to the groove surface at an appropriate angle, or by increasing the welding current to obtain a predetermined penetration. In order to secure the angle, it is necessary to widen the groove width to eliminate the interference with the welding torch 6, so that the number of laminated layers increases and the welding condition range for obtaining an appropriate laminated state and penetration There were practical problems such as being narrow.

Further, in the welding procedure, FIG.
In the prior art shown in FIG. 2, it is necessary to finish weld the corner portion of the prism 9 by manual welding, and in the prior art in which the ceramic tab 22 shown in FIG. 21 is used for the corner portion of the prism 9, the welding torch 6 and the ceramic are used. This method could not be used with narrow I-shaped groove 10, due to interference of tabs 22.

Further, in JP-A-59-202183, as shown in FIG. 23, two sets of wire feeding parts 40 and 41 in which downward and upward bending habits are added to the welding wire 8 by winding rollers 38 and 39, respectively. There is disclosed a method of simultaneously welding the lower side and the upper side of the groove 10 portion of the prism 9 while moving them back and forth in the horizontal direction by using. However, this method requires two sets of wire feeding parts 40 and 41, and the downward and upward bending habits of the two wires 8 are determined by the winding method on the winding rollers 38 and 39, respectively. The bending tendency of 8 cannot be changed.

Therefore, after the lower part of the groove 10 is welded while the wire feeding part 40 of the welding wire 8 having the downward bending tendency is always moved forward in the horizontal direction, the upward bending tendency is generated. It is necessary to weld the upper side of the groove 10 by following the wire feeding part 41 included in the welded welding wire 8. Therefore, during the reciprocating welding operation, it is necessary to return the wire feeding parts 40 and 41 to the start line again in the returning path to start the wire feeding part 40 included in the welding wire 8 always having the downward bending tendency in advance. Another problem is that the welding work time is wasted.

The object of the present invention is to efficiently use the optimum welding method and procedure when performing multi-layer welding in a horizontal position by an automatic welding machine when connecting prisms to each other by welding at an installation site. It is to provide a welding technique capable of welding.

It is another object of the present invention to provide a welding device which is optimal for connecting prisms to each other by welding at the site of installation.

Another object of the present invention is to provide a groove for automatic welding, which is optimum for connecting prisms to each other by welding at the site of installation.

Another object of the present invention is to provide a structure to be welded obtained by an efficient automatic welding method.

[0031]

The above objects of the present invention can be achieved by the following constitutions. That is, using a welding head having a welding torch, a welding power source, a control device, and an automatic welding device having a cooling water supply device, a guide device having a mounting function is arranged on the groove joint surface of the welded portion, and at least the welding is performed. In an automatic welding method in which a head is mounted on a guide device and welding is performed while moving on the guide device, at least three sets of wire feeding parts are arranged side by side in the wire feeding direction in the welding head, and the three sets of wires are arranged. Out of the feeding parts, the axial position of the wire feeding part positioned between the two sets of wire feeding parts is upward or downward with respect to the axis connecting the two wire feeding parts located outside. This is an automatic welding method in which at least the upper surface side and the lower surface side in the groove joint are welded by adding a bending tendency in the upper surface direction or the lower surface direction of the groove joint to the wire when the wire is fed.

In the above-described automatic welding method of the present invention, the inside of the groove joint is divided into two passes for each welding layer, that is, the lower side surface and the upper side surface, and multi-layer welding is performed over the entire area inside the groove joint. desirable. Further, in the above-described automatic welding method of the present invention, the axial position of the wire feeding component located between the two sets of wire feeding components is downward with respect to the axis connecting the two sets of wire feeding components located outside. By shifting the wire, welding is started from one end of one side of the groove joint to the other end while adding a bending tendency to the lower side of the groove joint during wire feeding. , The welding run is stopped at the other end, the welding end end is processed, the welding head is moved to the position where the next pass is welded, or the welding is continued at the stop position and the next pass is welded. By the time you start
By shifting the axial position of the wire feeding part located between the two sets of wire feeding parts upward with respect to the axis connecting the two sets of wire feeding parts located outside Start welding from the other end to the one end of one side of the groove joint while adding a bending tendency in the direction of the upper side of the groove joint, and stop the welding running at the other end. However, the end of welding can be processed.

Further, in the above-described automatic welding method of the present invention, the axial position of the wire feeding component located between the two sets of wire feeding components is set to the axis connecting the two sets of wire feeding components located outside. By displacing the wire downwardly, a bending tendency in the lower side surface direction of the groove joint is added to the wire at the time of feeding the wire, and at least one of the four groove joint surfaces has one end to the other. After starting the welding of the lower side surface toward the end of the, stopping the welding running at the other end, performing the processing of the welding end end, and moving the welding head to the position to weld the next pass, Alternatively, two sets of wire feeding, which are still in the stop position and are located outside the axial position of the wire feeding part located between the two sets of wire feeding parts, before starting welding of the next pass. By shifting upwards with respect to the axis connecting the parts, Starting the welding from the other end of the groove joint to the one end while adding a bending tendency in the upper surface direction of the groove joint to the wire at the time of feeding, and Welding of the upper surface of the groove joint is started toward the end, and when one end is reached, welding travel is stopped, the end of welding is processed, and the welding is performed at the next pass. After moving the welding head or in the stop position and before starting the welding of the next pass, move the wire in the direction to move the welding torch away from the welded layer, and By repeating the same welding procedure in sequence, multi-layer welding can be performed over the entire region inside the groove joint.

In the above-described automatic welding method of the present invention, the two welding heads are used to make the two opposing surfaces of the member to be welded substantially orthogonal to each other and substantially orthogonal to the two opposing surfaces of the member to be welded. A method of welding before welding the two surfaces may be used. For example, the welding torch of the present invention is a narrow groove joint welding torch, the welding power source is a MAG welding power source, the member to be welded is a prism, and the welding groove joint of the prism is an I-shaped narrow groove. Use as a joint.

The present invention has the following constitution. That is, using a welding head having a welding torch, a welding power source, a control device, and an automatic welding device having a cooling water supply device, a guide device having a mounting function is arranged on the groove joint surface of the welded portion, and at least the welding is performed. In an automatic welding device in which a head is mounted on a guide device and welding is performed while moving on the guide device, at least three wire feeding parts are arranged side by side in the wire feeding direction in the welding head, and the three wire pairs are arranged. Of the feeding parts, the wire feeding parts located between the two sets of wire feeding parts can be moved upward or downward with respect to the axis connecting the two sets of wire feeding parts located outside. It is an automatic welding device configured. The automatic welding apparatus of the present invention includes a welding head guide device provided with horizontal and vertical driving devices, or a welding head and guide devices corresponding to two facing surfaces of a member to be welded. Anything is fine.

The present invention has the following constitution. That is, it is a welded structure characterized in that the weld groove joint portion is welded by the automatic welding method of the present invention. And
As the welded structure, the welded structure may be a prism having an I-shaped weld groove joint shape.

[0037]

In order to make the present invention easier to understand, the drawings will be briefly described, but these drawings are merely examples of the present invention. As shown in FIGS. 1 and 2, at least three sets of wire feeding parts (rollers 2 to 5) are arranged side by side in the wire feeding direction in the wire feeding unit 1 at the time of feeding the welding wire 8. Of the wire feeding parts (rollers 2 to 5) of the set, two sets of wire feeding parts (rollers 2,
If the wire feeding part (roller 4) located between the two sets of wire feeding parts (rollers 2, 3, 5) is below the axis connecting the parts 3, 5), Located 2
In the set, the welding wire 8 is fed to the narrow groove torch 6 along the outer diameter of the roller 3 below the welding wire feeding parts (rollers 2, 3) on the side of the torch 6 of the narrow groove 10 of the prism 9. Therefore, a downward bending tendency is added to the welding wire 8 and the wire 8 comes out downward from the narrow groove torch 6, so that the tip of the welding wire 8 can aim at the corner portion 15 of the lower surface of the groove 10. The lower surface of the narrow groove 10 can be welded without tilting the narrow groove torch 6.

When the welding wire feeding component (roller 4) is located above the axis connecting the two wire feeding components (rollers 2, 3, 5) as shown in FIG. , Welding wire feeding parts (roller 2,
Since the welding wire 8 is fed to the narrow groove torch 6 along the outer diameter of the roller 2 on the upper side of 3), an upward bending tendency is added to the welding wire 8 so that the wire 8 moves upward from the narrow groove torch 6. Since it comes out, the tip of the welding wire 8 can aim at the corner portion 15 ′ of the upper surface of the groove 10, and the upper surface of the narrow groove 10 can be welded without tilting the narrow groove torch 6. .

Next, in the welding procedure, the prism 9 shown in FIG.
As shown in the front view of the I-shaped narrow groove 10, the welding of the first pass is started from the point A, the welding traveling is stopped at the point B, the crater process is started, and the welding wire feeding part ( After raising the roller 4) to a position where an upward bending tendency can be added to the welding wire 8, the narrow groove torch 6 is moved to the upper point C, and welding of the second pass is started from the point C. At the point, the welding traveling is stopped and the crater process is started, and the welding wire feeding part (roller 4) is lowered to move the welding wire 8
After the position where the downward bending tendency can be added to, the welding of the first layer is completed. Furthermore, the welding of the first pass of the next layer is
After the welding of the first layer is completed at point D, the narrow groove torch 6 is groove 1
In the direction away from 0, a distance suitable for welding the next layer is moved (see FIG. 9 (b)), and the lower A
Move to a point. By repeating such a welding procedure, lamination can be continuously performed for the groove depth, so that efficient automatic welding can be performed.

[0040]

Embodiments of the present invention will be described with reference to the drawings. FIG. 4 shows the structure of an automatic prismatic welding device embodying the present invention. The prismatic automatic welding device includes a welding head 11, a cooling water pump 16, a welding power source 17, a control device 18, and a traveling unit 19.
And cables (control cable, cooling water hose, shield gas hose, power cable, ground, etc.). The welding head 11 is composed of a traveling unit 19 and a wire feeding unit 1, and the like, and a torch up-and-down mechanism 25 and a torch front-back mechanism 26 are provided between the traveling unit 19 and the wire feeding unit 1. As shown in FIGS. 1 and 2, the wire feeding unit 1 includes three pairs of feeding rollers, an upper wire feeding roller 2, a lower wire feeding roller 3, a bending addition roller 4 and a guide roller 5. With rollers.

Note that FIG. 4 also shows the linear rails 12 and 13 provided on the prism 9, and the linear rails 12 and 13 are also shown.
A traveling unit 19 of the prismatic automatic welding device travels on the top.

FIG. 1 shows the wire feeding mechanism of the wire feeding unit 1 in the vicinity of the welded portion of the prism 9. The bending addition roller 4 can be moved in the vertical direction (the vertical movement mechanism is not shown), and the upper wire feeding roller 2 is pressed against the lower wire feeding roller 3 by a spring (not shown) to lower the wire feeding roller 3. A motor (not shown) is attached to the supply roller 3. The wire 8 sent to the wire feeding unit 1 passes from the wire reel 7 through the guide roller 5 and the bending addition roller 4, is sandwiched by the upper wire feeding roller 2 and the lower wire feeding roller 3, and the narrow tip torch 6 is provided. Sent to. When performing automatic welding, the welding head 11 is suspended and moved on the linear rails 12 and 13 attached to the prism 9, as shown in FIGS. 4 and 5.

The narrow groove welding torch 6 of the welding head 11 is directed toward the groove 10 of the prism 9 shown in FIG.
Can be moved in the left, right, up, and down arrow directions in FIG. That is, the traveling unit 19 can move in the left-right direction with respect to the groove 10 of the prism 9, the torch up-and-down mechanism 25 can move in the up-and-down direction, and the torch front-rear mechanism 26 can move in the front-rear direction. The groove welding torch 6 can be positioned at any position.

As shown in FIGS. 1 and 2, the wire feeding unit 1 takes out the wire 8 from the wire reel 7 and feeds it through the narrow groove welding torch 6 into the groove 10 of the prism 9 as a consumable electrode. The bending addition roller 4 is movable up and down, and as shown in FIG.
Is below the wire feeding unit 1, the wire 8
Is sent to the narrow groove welding torch 6 along the outer periphery of the lower wire feeding roller 3, so that the wire 8 is plastically deformed, that is, bent, by the lower wire feeding roller 3, and the narrow groove welding torch is provided. It comes out from the tip of 6. Figure 2
Shows the case where the bending addition roller 4 is located above the inside of the wire feeding unit 1. In this case, contrary to FIG. 1, the wire 8 comes out upward from the narrow groove torch 6. The present invention is a welding method utilizing this wire bending behavior. The vertical width of the groove 10 of the prism 9 (hereinafter, simply referred to as groove width).
Is preferably 10 to 14 mm.

Next, the welding lamination procedure will be described below. First,
The bending addition roller 4 is set below the wire feeding unit 1, the lower wire feeding roller 3 is rotated, the wire 8 is sandwiched between the upper wire feeding roller 2 and the narrow wire welding torch 6. The wire 8 that has been fed out from the tip of the torch 6 is bent downward as shown in FIG.

Next, as shown in FIG. 8A, the narrow groove welding torch 6 is inserted into the parallel groove 10, and the wire 8 from the tip of the torch 6 is moved to the lower groove of the parallel groove 10. The vertical and front-back positions of the narrow groove welding torch 6 are set at the positions aiming at the corners 15. In this state, an arc is started to start welding, and the narrow groove welding torch 6 is moved toward the prism 9 in the left or right direction while using the wire 8 as a consumable electrode. This welding method will be referred to as a narrow groove MAG welding method. As a result, the 1-1 beads shown in FIG. 1 are formed.

Next, as shown in FIG. 2, the bending addition roller 4 is
Is moved to the upper side in the wire feeding unit 1, and the wire 8 is fed from the wire reel 7 to the narrow groove welding torch 6 side by the wire feeding rollers 2 and 3. At this time, the wire 8 with a downward bend is left in the narrow groove welding torch 6 by the length L, and when the wire 8 is fed by the length L, the wire 8 has the narrow groove. The welding torch 6 comes out from the tip of the torch 6, and as shown in FIG. 2, the wire 8 coming out of the tip of the torch 6 is bent upward.

When the narrow groove welding torch 6 is located at the same position as shown in FIG. 8A, the wire 8 moves the upper groove corner portion 15 'in the parallel groove 10 as shown in FIG. 8B. It doesn't always aim. Therefore, as shown in FIG. 8 (c), it may be necessary to move the narrow groove welding torch 6 upward. The amount of bending of the wire 8 can be adjusted by changing the position of the bending addition roller 4 in the wire feeding unit 1. Therefore, the vertical movement amount of the narrow groove welding torch 6 is increased, and the groove 10 of the prism 9 is increased. Was 1 mm in the width of 14 mm. In the state of FIG. 8 (c), arc start is performed to start welding, and the narrow groove welding torch 6 is moved horizontally with respect to the prism 9 in the left or right direction. As a result, the 1-2 beads shown in FIG. 1 are formed. This completes the welding of the first layer.

Next, the bending addition roller 4 is moved to the lower side of the wire feeding unit 1, and the wire 8 is fed to bring it into the state of FIG. 1 again, and as shown in FIG. Lower the narrow groove welding torch 6 backward. Further, the vertical position of the torch 6 is adjusted and the second layer is welded. By repeating the above procedure, the layers are welded in one layer and two passes, and the state including FIG.

A procedure for automatically and continuously welding the prism 9 using the narrow groove MAG welding method will be described below. 5 and 6
Shows the welding procedure of the prism 9, and FIG. 3 shows the movement of the narrow groove torch 6 in the narrow groove. 5 and 6 are views seen from the horizontal cross-sectional direction of the prism 9, and FIG. 3 is a view seen from the side direction of the groove 10 portion of the prism 9. As shown in FIG. 5, the fixture attached to the prism 9 is not shown, and the welding head 11 is suspended on the linear rails 12 and 13.

The welding procedure of the prism 9 is as follows. First, the welding head 11 is run on the linear rail 13 shown in FIG. 5, and the striped pattern is formed on the portion of the groove 10 on the two surfaces of the prism 9 facing each other in FIG. The welding layers shown by are welded in order from the back of the groove 10,
The opposite groove portions 10 of the prism 9 are welded with the width of the inner dimension of the prism 9. Next, the welding layer shown in a striped pattern on the two faces of the groove 10 at the opposite positions of the remaining prisms 9 shown in FIG.
Are sequentially welded from the back of the groove 10, and the width of the outer dimension of the groove 10 portion of the prism 9 facing each other is welded.

The bending behavior of the tip of the wire 8 is directed downward as shown in FIG. 1, and the narrow groove welding torch 6 is brought to the point A shown in FIG. Arc start at this position,
Narrow groove MAG welding is started.

First, the welding head 11 travels on the linear rail 13 shown in FIG. 5, and the traveling unit 19 moves on the linear rail 13 to the right at the welding speed set by the controller 18 (FIG. 4), and the point B is reached. It stops when it detects (see also FIG. 3). As a result, the 1-1 beads shown in FIGS. 1 and 10 are formed. The distance between points A and B is close to the inner dimension of the prism 9. For detection of point B, a limit switch (not shown) is used to integrate the traveling distance by a pulse generator (not shown) built into the traveling head 19 and control device 1
8 (FIG. 4) may be used for comparison. Input to the control device 18 may be performed manually, teaching such as a robot, or sensing by a sensor. Any method may be used as long as the setting and detection of points A to D in FIG. 3 or the setting of the moving amount of the narrow groove welding torch 6 in the vertical direction and the front-back direction and the calculation method are other appropriate methods. good.

With the traveling of the welding head 11 being stopped, the welding crater process is performed, and the narrow groove welding torch 6 is shown in FIG. 8 (c).
As shown in FIG. 8 (b), the bending addition roller 4 is moved upward, and at the same time, the bending addition roller 4 is moved upward in the welding head 11. The amount of upward movement of the torch 6 varies depending on the width of the groove 10, the welding conditions and the amount of wire bending, but since the welding conditions and the wire bending can be constant, they can be determined by the groove width. By measuring the groove width before welding and inputting it into the control device 18, the amount of upward movement of the torch is automatically determined. The crater processing time is about 5 seconds, and the wire 8 for the length L (about 250 mm) remaining in the narrow groove welding torch 6 is about 2.
Since the torch 6 comes out from the tip of the torch 6 in 5 seconds, the tip of the wire 8 is bent upward as shown in FIG.

The position of the torch 6 is also at point C (see FIGS. 3 and 5) at the end of the crater process, that is, at the end of welding. Here, the arc is automatically restarted and the welding head 1
As shown in FIG. 3, welding is performed while moving 1 toward the groove 10 to the left. Then, when the point D is detected, welding crater processing is started, welding traveling is stopped, and the bending addition roller 4 is moved downward in the welding head 11.
After the end of the crater, the narrow groove welding torch 6 is automatically lowered by a command from the control device 18, and as shown in FIG. 9B, the narrow groove welding torch 6 is moved backward in the groove 10 as compared with the case of FIG. 9A. Lower it (the mechanism for moving the torch 6 back and forth is not shown, but is in the wire feeding unit 1). The amount of backward movement depends on the groove width and welding conditions, but since the welding conditions can be made constant, it can be determined only by the groove width. This is determined only by inputting the groove width to the control device 18, like the amount of upward movement.

The groove width is 14 mm and the welding conditions are welding current 2
20A, welding voltage 26V, welding speed 220mm / min
The backward movement amount shown in FIG. 9 is 5 mm. That is, the bead height of one layer is 5 mm, and the prism having a plate thickness of 25 mm can be laminated with the groove in six layers and 12 passes including one layer of extra reinforcement.

After moving the torch 6, that is, at the position of point A in FIG. 3, the arc is automatically restarted and welding is performed in the same sequence as the first layer. By repeating this, as shown in FIG. 5, the two surfaces facing each other are welded with the inner width of the prism 9.

FIG. 10 (a sectional view taken along the line AA in FIG. 4) shows a cross-section obtained by welding up to the extra deposits (6-1 and 6-2). Also,
As shown in FIG. 11 (a), since the left and right ends of the extra bead 14 are uneven, a grinder is used to smooth the end surfaces of the irregularities at both ends of the extra bead 14. This work will take a few minutes. At this time, when the two welding devices simultaneously weld the groove 10 portions on the two opposing surfaces of the prism 9, the inclination due to the welding deformation of the prism 9 becomes small.

FIG. 12 shows a state in which two welding heads 11 are suspended on a rail 13 attached to a prism 9. The upper and lower prisms 9 are connected and fixed by an erection piece 27, and the rails 12 and 13 are fixed to the prism 9 by a rail support 28. In this state, welding is performed as shown in FIGS. After the welding is completed, the erection piece 27 is removed.

Next, as shown in FIG. 6, the welding head 11 is moved to the linear rail 12, and the groove portions 10 on the opposite surfaces of the prism 9 are welded in the same manner as described with reference to FIG. In this case, there is a welding width corresponding to a dimension close to the outer dimension of the prism 9 which is a longer distance in the horizontal direction than the welded portion shown in FIG. In FIG. 13, after welding the two surfaces on one side, two welding heads 11 are mounted on the rail 12
Shown in a suspended state. In this state, welding is performed for a dimension close to the outer dimension of the prism 9 (see FIG. 11).

According to the above-described embodiment of the present invention, since the shape of the groove 10 is parallel, the number of steps for manufacturing the groove 10 is 1/3 to 1 / for the conventional square-shaped groove 10 '. It took 4 hours. In addition, when the shape of the groove 10 is a V-shape (Fig. 1
7 (a)) and the case of the I-shape (FIG. 17 (b)), when the plate thickness of the prism 9 is 50 mm, the welding method applicable to the case of the I-shape of this embodiment is used. Tip width 12m
Welding was possible with 18 passes at m, but 34 passes were also required in the case of the square-shaped groove 10 '.

The above embodiment is also excellent for automation. Since the shape of the groove 10 is originally parallel, the groove accuracy is good (the dimensional error when manufacturing the groove 10 is small).
However, as shown in the specific example, the dimensional error of the groove 10 is only influenced by the groove width, and the shape of the groove 10 can be recognized by using a sensor or the like, and it can be dealt with. It is possible to provide a device that can be easily used, which is required at the construction site, without the need for treatment.

Further, in the welding method of the above-mentioned embodiment, the corner portions 15 and 15 'of the groove 10 which are apt to cause defective penetration (FIG. 8).
(A) and FIG. 8 (b)) can be aimed by the wire 8 whose tip is bent, so that the melting failure is eliminated. In addition, FIG.
Even if the position of the torch 6 is deviated by about 1 mm in the vertical direction and about 2 mm in the front-back direction as compared with the wire 8 whose tip is not bent, the welding margin by the wire 8 whose tip is bent does not become a welding failure.

Further, the welding procedure is repeated every several passes, and the cables to be welded to the welding head 11 reciprocate in a straight line, so that there is no need for the operator to monitor it as in the case of circular welding. The welding head 11 of the table can be operated, and the number of on-site man-hours is significantly reduced. Also, the prism 9
When the grooves 10 facing each other are welded at the same time, the inclination due to the distortion of the prism 9 is also reduced.

[0065]

According to the present invention, since the shape of the groove is parallel, the number of man-hours required to process and manufacture the groove is 1 as compared with the conventional grooved groove.
The time required is / 3 to 1/4, the groove precision is good, and the present invention is excellent for automation. Further, in the welding method of the present invention, since it is possible to aim with a wire having bent beveled corners, which are apt to cause defective penetration, defective penetration is eliminated, and the same welding is repeated, resulting in a significant reduction in the number of on-site man-hours.

[Brief description of drawings]

FIG. 1 is a side view showing a specific example of a welding unit according to the present invention.

FIG. 2 is a side view showing a specific example of a welding unit according to the present invention.

FIG. 3 is a front view of a prismatic portion showing a welding sequence according to an embodiment of the present invention.

FIG. 4 is a configuration diagram of an automatic welding apparatus that embodies a welding method according to an embodiment of the present invention.

FIG. 5 is a sectional view of a horizontal portion of a prism, showing a welding procedure according to an embodiment of the present invention.

FIG. 6 is a sectional view of a horizontal portion of a prism, showing a welding procedure according to an embodiment of the present invention.

FIG. 7 is an external view of a prism to which the welding method according to the embodiment of the present invention is applied.

FIG. 8 is a side view of a prismatic groove portion to which the welding method according to the embodiment of the present invention is applied.

FIG. 9 is a side view of a prismatic groove portion to which the welding method according to the embodiment of the present invention is applied.

10 is a cross-sectional view taken along the line AA of FIG.

FIG. 11 is a horizontal cross-sectional view of a prismatic portion showing the welding procedure of the embodiment of the present invention.

FIG. 12 is a perspective view showing a state in which two welding heads of one embodiment of the present invention are attached to a prism and a welding operation is performed.

FIG. 13 is a perspective view showing a state in which two welding heads according to an embodiment of the present invention are attached to a prism and welding work is performed.

FIG. 14 is a side view of a groove showing a torch position according to a conventional technique.

FIG. 15 is a side view of a groove showing a torch position according to a conventional technique.

FIG. 16 is a perspective view showing a joining structure of prisms.

FIG. 17 is a vertical cross-sectional view of a groove portion showing a welded laminated state when the groove shape is a V-shape and when the groove shape is an I-shape.

FIG. 18 is a vertical cross-sectional view showing a groove-shaped groove welded laminated state.

FIG. 19 is a side view of a groove showing a torch position according to a conventional technique.

FIG. 20 is a horizontal sectional view of a prism, showing a welding procedure according to the related art.

FIG. 21 is a horizontal sectional view of a prism, showing a welding procedure according to a conventional technique.

FIG. 22 is a horizontal cross-sectional view of a prism, showing a state after completion of automatic welding according to a conventional technique.

FIG. 23 is a perspective view showing a state where welding work of a groove of a prism is performed by using two welding devices of a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wire feeding unit, 2-5 ... Wire feeding roller 6 ... Narrow groove welding torch, 7 ... Wire reel, 8 ... Wire, 9 ... Square column, 10 ... Groove, 11 ... Welding head, 12,
13 ... Straight rail 14 ... Bead, 15, 15 '... Bevel corner part, 17 ... Welding power source 18 ... Control device, 19 ... Traveling unit, 25 ... Torch up / down mechanism 26 ... Torch front / rear mechanism, 27 ... Erection piece, 2
8 ... Rail support

Claims (11)

[Claims] 1. An automatic welding device comprising a welding head having a welding torch, a welding power source, a control device, and a cooling water supply device is used, and a guide device having a mounting function is arranged on a groove joint surface of a welded portion. In an automatic welding method in which at least a welding head is mounted on a guide device and welding is performed while moving on the guide device, at least three sets of wire feeding parts are arranged side by side in the wire feeding direction in the welding head. Of the wire feeding parts of the set, the axial position of the wire feeding part located between the two sets of wire feeding parts is set upward or with respect to the axis connecting the two wire feeding parts located outside. By shifting the wire downwards, at least the upper surface side and the lower surface side in the groove joint are welded while adding a bending tendency to the wire in the upper surface direction or the lower surface direction of the groove joint when feeding the wire. Welding method. 2. The multi-pass welding is carried out over the entire region inside the groove joint by dividing the inside of the groove joint into two passes for each welding layer, a lower side surface and an upper side surface. Automatic welding method. 3. The wire is obtained by shifting the axial position of the wire feeding component located between the two sets of wire feeding components downward with respect to the axis connecting the two sets of wire feeding components located outside. Welding is started from one end of one side of the groove joint to the other end while adding a bending tendency to the lower surface direction of the groove joint at the time of feeding, and at the other end After stopping the welding run, processing the end of welding, moving the welding head to the position where the next pass is welded, or at the stop position and before starting the welding of the next pass, By shifting the axial position of the wire feeding part located between the two sets of wire feeding parts upward with respect to the axis connecting the two sets of wire feeding parts located outside While adding a bending tendency in the upper side direction of the groove joint, Serial welding starts toward the other end to said one end,
3. The automatic welding method according to claim 1, wherein welding traveling is stopped at the other end, and the end of welding is processed. 4. The wire is obtained by shifting the axial position of the wire feeding component located between the two sets of wire feeding components downward with respect to the axis connecting the two sets of wire feeding components located outside. While imparting a bending tendency in the direction of the lower side of the groove joint to the wire during feeding, at least one of the four groove joint surfaces faces the lower side surface from one end to the other. Start welding, stop welding run at the other end,
After processing the end of welding, move the welding head to the position where the next pass is welded, or remain at the stop position and before starting welding of the next pass, feed two sets of wires. By shifting the axial position of the wire feeding part located between the parts upward with respect to the axis connecting the two wire feeding parts located outside, the upper surface of the groove joint to the wire during wire feeding Starting welding from the other end of the groove joint to the one end while adding a bending tendency to the direction, and from the other end to the one end, on the groove joint When side welding is started and one end is reached, welding traveling is stopped, the end of welding is processed, and the welding head is moved to the position where welding for the next pass is performed or the The welding toe before starting the next pass welding. The multi-pass welding is performed over the entire region inside the groove joint by moving the wire in a direction away from the welded layer and sequentially repeating the same welding procedure as the two-stage welding process. 1. The automatic welding method described in 1. 5. Two welding heads are used to weld two facing surfaces of a member to be welded simultaneously or substantially simultaneously before welding two surfaces substantially orthogonal to the two facing surfaces of the member to be welded. Welding, The automatic welding method in any one of Claims 1-4 characterized by the above-mentioned. 6. The welding torch is a narrow groove joint welding torch, the welding power source is a MAG welding power source, the member to be welded is a prism, and the welding groove joint of the prism is an I-shaped narrow groove. It is a joint, The automatic welding method in any one of Claims 1-5. 7. A welding head having a welding torch, a welding power source, a control device, and an automatic welding device having a cooling water supply device are used, and a guide device having an on-board function is arranged on a groove joint surface of a welded portion. In an automatic welding device in which at least a welding head is mounted on a guide device and welding is performed while moving on the guide device, at least three sets of wire feeding parts are arranged side by side in the wire feeding direction in the welding head. The wire feeding component located between the two sets of wire feeding components is moved upward or downward with respect to an axis connecting the two sets of wire feeding components located outside of the pair of wire feeding components. An automatic welding device with a movable structure. 8. The automatic welding apparatus according to claim 7, wherein the guide device of the welding head is provided with horizontal and vertical driving devices. 9. The automatic welding apparatus according to claim 7, further comprising a welding head and a guide device for the welding head respectively corresponding to the two surfaces of the member to be welded which are opposed to each other. 10. A welded structure in which a weld groove joint portion is welded by the automatic welding method according to any one of claims 1 to 6. 11. The structure to be welded comprises a prism having an I-shaped weld groove joint shape.
The welded structure described.