JPH05245642A - Narrow gap mag all position welding method - Google Patents

Abstract

PURPOSE:To provide the narrow gap MAG all position welding method capable of reducing man-hours, improving the welding quality and executing remote control or unmanned operation. CONSTITUTION:A welding wire 1 is formed into a doglegged shape by a couple of bend forming feed gears 4 and 5 with two electrodes shifted in the weld line direction by using the welding wire 1 having <=1.0mmphi diameter. While bend habits are formed, respectively to groove walls 14 and 14' in opposition to give directivity, arcs are oscillated and started from a starting point 25 of a flat position part of a pipe to make a round. At a point of time when the start point 25 of a preceding bead is molten, the arcs are reversed and the operation to change the welding direction and make a round is repeated and build-up is performed in order without interrupting the arcs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a narrow groove MAG all-position welding method applied to pipes of various large-sized thick plate structures.

[0002]

2. Description of the Related Art As a welding method of this kind, conventionally, as shown in FIG. 4, ascending welding from 6 o'clock φ to 12 o'clock F for each pass, and FIG. There are one-way continuous welding methods as shown, but any of them requires man-hours, which hinders remote operation control and unmanned automatic welding.

That is, in the former case, the start portion 20 and the crater portion 19 are generated in each pass, and after the arc is interrupted in the crater portion 19, the welding torch is reversed and returned until 6 o'clock (start portion 20), and is returned again. Repeatedly setting and starting causes a lot of trouble and loss when reversing.
Further, as shown in FIGS. 4B and 4C, the penetration failure 2 occurs at the welded joint of the start portion 20 and the crater portion 19.
1 is caused, and further, it takes a lot of man-hours to smoothly form the raised meat 22 generated in each pass with a grinder or the like.

In the latter case, V is a downward welding and V'is an ascending welding at the positions of V and V'in FIG. 5A, the descending welding is a high speed welding for holding the molten metal, and the ascending welding is a low welding. Since the welding is speed welding, there is a large difference between the raised thicknesses t and t'of the weld metal at both points. Further, since the welding torch is one-way continuous welding, there is a problem that it is difficult to process cables, hoses and the like. In addition, 2 in FIG.
3 is the uppermost bead and 24 is the lower bead.

Further, since both of them have one electrode, in the former case, first, as shown in FIG. 4A, the arc is started at the upward φ point, the welding is ended at the downward F point, and further. The wire direction is adjusted again for one groove wall, and welding is started again from the upward φ point to the point F, and the work is repeated for both groove walls, resulting in defects. There was a drawback that the number of occurrences increased. Then in the latter,
As shown in FIG. 5C, the wire direction needs to be changed from the one-direction wall side to the opposite wall side, and the shift method is difficult and there are many defects.

Therefore, an object of the present invention is to provide a narrow groove MAG all-position welding method capable of reducing man-hours and improving welding quality and enabling remote operation and unmanned welding.

[0007]

The welding method according to the present invention for achieving the above-mentioned object is 1.0 mm in one-layer two-pass laminated welding by thick plate narrow groove gas metal arc welding.
Two electrodes that use a welding wire of φ or less and are shifted in the direction of the welding line by the length of the molten metal or more. The welding wire is formed into a dogleg shape by a pair of forming gears and the groove walls facing each other. While pointing with a bending tendency toward the right and left walls of the arc, oscillate the arc, start from the downward posture part of the pipe and make a round, and reverse it when the start point of the previous bead is melted It is characterized by repeating the operation of changing the welding direction and making one round, and sequentially laminating without interrupting the arc.

[0008]

[Function] The welding wire is formed into a dog-legged shape and fed, and at the same time, the arc is oscillated at a high speed to perform welding, thereby promoting the spread of the molten meat due to the stirring effect of the molten metal, and stable welding without dripping In addition to the above, the simultaneous welding of two electrodes makes it possible to simultaneously perform distribution welding on both groove wall surfaces. Also, by performing bead splicing and reversing at 12 o'clock, which is the downward welding that enables the most stable welding, the penetration of the seam is sufficiently secured and defects are eliminated. Orientation section V
And V ', the thickness of the laminated weld metal is balanced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a welding apparatus for carrying out the welding method of the present invention, FIG. 2 is a laminated sectional view of welding bead start and end portions by the welding method of the present invention, and FIG. Is.

As shown in FIG. 1, a welding wire 1 having a small diameter.
Is straightened to a certain extent by passing through the wire strainer 2, passes through the wire guide mouthpiece 3, and is formed into a dogleg shape by the bending forming feed gears 4 and 5, and then the wire guiding pipe 6 is inserted. It is configured to be sent out from the power feeding chip 7.

Then, the bent wire 13 sent out is
By setting the movement of the slide 11 driven by the motor 12 to the left or right, the meshing points of the bending forming feed gears 4 and 5 are set as intersections, and the relative positions of the slide guides 6 and 5 to the wire guide tube 6 cause the groove walls 14 and 14 'to move. It is designed to point in the direction.

In the figure, 8 is a base plate for fixing the main welding head to a manipulator (not shown), 9 is a slide mounted on the base plate 8, and 10 is a handle of the slide 9.

2 and 3 show the locus of the welding bead and the stacking state by the welding method of the present invention. Groove wall 14,1
Two bending wires 13 or two electrodes oriented in the 4'direction are arranged as shown in FIG. 2, and the welding starts simultaneously from the starting point 25 in FIG.

The first layer proceeds in the clockwise direction in FIG. 2a, and is vertical downward welding at the point V, then upward welding at the point φ, and vertical improvement welding at the point V '. And reaches the start point 25 of F, both arcs sufficiently melt the weld metal at both start points and become the turning point 17, and then the welding progress direction is counterclockwise as shown in a and b of FIG. And welding proceeds. Further, when the electrode reaches the point F, the same movement is performed at the turning point 17 to reverse the point. It should be noted that at the turn-around point 17, the torch is pulled up by a distance of a further raised thickness each time.

By repeating this, from the arc start to the continuous welding to the final layer without interrupting the arc. During welding for one revolution (one rotation), the welding speed is the same in the downward welding position near point F and the upward welding position near point φ, but in the vertical welding position near points V and V ′. During downward welding, high-speed welding is performed so that the molten metal 18 does not precede the arc in the gravity direction, and during upward welding, the welding speed is set slower than downward and upward welding.
By repeating this, the swell is the same as in the upward and downward welds.

[0016]

EFFECTS OF THE INVENTION A welding wire of 1.0 to 0.6 mmφ is bent in a zigzag shape like a dogleg and directed toward the opposite groove wall surface to feed it to oscillate the arc at a high speed and in the welding direction. By performing 1-layer 2-pass welding at the same time with two electrodes with a gap, sufficient penetration can be obtained and groove width can be obtained as compared with conventional oscillating welding by 1-layer 1-pass or welding by straight wire which is pre-oriented and distributed welding. A flat weld bead that is not convex is formed throughout all the postures, and stable welding quality can be obtained.

Further, since the bead splicing is sufficiently melted and stabilized by reversing at the downward welding portion, welding can be performed up to the final pass by reversal continuous welding without interrupting the arc. Since there is no crater, there is no defect, molding work for that part is eliminated, and remote control and unmanned welding are achieved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a welding apparatus for carrying out a welding method of the present invention.

FIG. 2 is a laminated cross-sectional view of the start and end portions of the weld bead according to the welding method of the present invention.

FIG. 3 is likewise a locus of a weld bead and a stacking sectional view.

FIG. 4 is a locus and a laminated cross-sectional view of a welding bead by a conventional welding method.

FIG. 5 is a locus and a laminated cross-sectional view of a welding bead by different conventional welding methods.

[Explanation of symbols]

 1 Welding Wire 2 Wire Strainer 3 Wire Guide Mouth 4, 5 Bending Mold Feeding Gear 6 Wire Guide Tube 7 Feed Tip 8 Base Plate 9 Slide 10 Handle 11 Slide 12 Motor 13 Bending Wire 14 Groove Wall 15 Leading Bead 16 Trailing Bead 17 Turn-around point 18 Molten metal 25 Start point

Claims (1)

[Claims] 1. In 1-layer 2-pass laminated welding by thick plate narrow groove gas metal arc welding, a welding wire of 1.0 mmφ or less is used, and the length of the molten metal is shifted by more than the length of the molten metal in the welding line direction. With the two electrodes, the welding wire is shaped like a dogleg with a pair of shaping gears, and the arc is oscillated while directing with a bending tendency toward the right and left walls of the facing groove wall. Repeat the operation of starting from the facing position part and making one round, reversing when the starting point of the previous bead is melted and changing the welding direction
A narrow groove MAG all-position welding method characterized by sequentially laminating without interrupting the arc.