JPH04288971A - Narrow groove welding method - Google Patents

Abstract

PURPOSE:To obtain the deposition part having no welding defect by realizing one layer two pass welding in the case of welding of a narrow groove. CONSTITUTION:At the time of executing arc welding by leading a wire 3a which passes through a wire guide base 23 and is formed in a chevron shape by bend forming/feeding gears 13, 14, to a narrow groove 1, the wire is allowed to have directivity by shaking the wire guide base 23 to the left and the right and allowing the wire 3a to have a bend habit. Accordingly, an arc is generated between the front bead 8 and one groove wall 1a, and welding of one layer two pass is executed.

Description

[Detailed description of the invention]

The present invention relates to a welding method for welding a narrow gap in one layer in two passes.

0002

[Prior Art] As shown in FIGS. 4A, 4B, and 4C, there is a method for welding a narrow gap in a thick plate material by MAG welding or the like. 1, the wire 3 is rotated together with the wire guide cap 2 to rotate the arc 4, the wire 3 is twisted in advance to rotate the arc 4 generated, and the wire 3 is bent and the arc 4 is rotated. There is a method in which the wire guide cap 2 is swung from side to side.
At the outlet of the wire 3, the bending feed gears 5, 6
There is a method in which the arc 4 is bent and guided through the wire guide tube 7 to swing the arc 4 from side to side.

0003

[Problems to be Solved by the Invention] All of the above welding methods employ a one-layer, one-pass welding method. For example, as shown in FIG. 5, the bent wire 3a is fed to the approximate center of the groove 1, and melts both groove walls 1a, 1b almost simultaneously and evenly, so that the weld bead 8 becomes even more The layers are stacked in one pass.

In this case, as shown in FIG. 6(A), if the wire 3 is located in the center, the weld bead 8 will have even and sufficient penetration and complete welding will be performed, but as shown in FIG. 6(B)
As shown in Fig. 2, the wire 3 may be deflected and fed to one of the groove walls 1a due to improper adjustment of the bend, etc. In that case, uniform penetration may not be achieved, resulting in poor fusion and deposited metal. Misalignment occurs, and welding defects are inevitable. Similarly, if the groove width b becomes too large, both groove walls 1a and 1b
There is a lack of integration into the

[0005] Furthermore, when performing all-position welding, depending on the position and position, for example, when upward welding is performed, solidification of the molten metal inevitably occurs when laminating one layer in one pass, as shown in FIG. 3(B). It slows down in the center, resulting in a dripping convex bead shape, and defects 9 such as poor fusion occur on both groove walls. In other words, it was not possible to obtain a uniform bead shape and stable penetration quality throughout all positions. The problem of the molten metal convexing downward and the above-mentioned problem also occurs in other welding methods as shown in FIGS. 4(A), 4(B), and 4(C).

[0006]

[Means for Solving the Problems] The present invention solves the above problems in a narrow gap welding method in which a welding wire is passed between a pair of gears and supplied as a bent wire to a narrow gap.
It is characterized in that the welding wire is swung in a direction perpendicular to the wire feeding direction just in front of the gear so that the bending wire has directivity.

[0007]

[Function] Since the bending wire has directionality, the tip of the bending wire moves directionally between one wall and the other wall in a narrow gap, which means that the arc is deflected and each wall By melting a part of the front bead and repeating this welding, a two-pass laminated weld is made in one layer.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a gas shield consumable electrode welding apparatus used to carry out a method according to an embodiment of the present invention.

11 is a base plate forming the base of the device;
A slide 12 is provided thereon, and a pair of bent feed gears 13 and 14 are provided on the slide 12. The support stands 15 and 16 of these gears 13 and 14 are screwed into a right-hand threaded portion and a left-hand threaded portion, respectively, of a screw shaft (not shown) built into the slide 12. Therefore, by turning the handle 17 provided at the end of the screw shaft, the supports 15 and 16 are moved toward and away from each other, and the interval between the gears 13 and 14 is changed. In other words, the width of the wire 3 that is bent by the gears 13 and 14 can be changed. Note that the gears 13 and 14 are driven and rotated by a feed motor (not shown).

A slide 19 is supported directly above the gears 13 and 14 by legs 18 provided on the base plate 11. A slide block 20 is mounted on the slide 19, and a screw shaft 22 driven and rotated by a motor 21 is screwed onto the slide block 20. The slide block 20 is provided with a wire guide cap 23 passing through it vertically. A wire strainer 24 is integrally attached to the upper part of the wire guide cap 23. The wire strainer 24 consists of a frame 25 and a plurality of rollers 26 arranged vertically within the frame 25.

On the other hand, a gear 13 is provided on the bottom surface of the base plate 12.
, 14, a wire guide tube 27 is connected to the wire guide tube 27 centered on the center between them. The wire guide tube 27 is connected by a holder 28 or the like. A power supply tip 29 is provided at the lower end of the wire guide tube 27 for supplying power to the wire.

Next, the narrow gap welding action by the above device,
That is, a method according to an embodiment of the present invention will be explained. The welding wire 3 attached above the welding device and wound into a coil is straightened to a state close to a straight line to some extent by passing through the wire strainer 24, and reaches the bent feeding gears 13 and 14 directly below.

The wire 3 is bent into a dogleg shape by the bending and forming feed gears 13 and 14, and is fed downward at a feeding speed depending on the welding current value, passes through the wire guide tube 27, and the wire 3 is bent into a dogleg shape. An arc 4 is generated between the wall surfaces 1a and 1b forming the narrow gap 1,
Welding is done.

In the present invention, the slide block 20 directly above the gears 13 and 14 is driven by a motor 21 to slide left and right. Wire guide cap 23 together with slide block 20
By swinging in the left-right direction, that is, in the direction perpendicular to the wire feeding direction, the wire 3 is bent as shown in FIGS. 2A and 2B.

For example, when the wire guide cap 23 is moved to the left as shown in FIG. 2(A), the gears 13, 1
The wire 3 is bent to the left with the interlocking point of 4 as the intersection point, and the wire 3a sent out through the wire guide tube 27 is directed toward the left side groove wall 1a.
A weld bead 8a is formed. On the other hand, when the wire guide cap 23 is moved to the right as shown in FIG.
A weld bead 8b directed toward the b side is formed. Therefore, by repeating this oriented welding alternately, welding is further progressed in two passes.

Here, the bending width of the wire 3 is adjusted by operating the handle 17 according to the groove width b and the welding posture, and the widths of the weld beads 8a and 8b are arbitrarily set. The stirring effect of the molten metal due to the high-speed oscillation of the set width promotes the spread of the molten metal, creating a flat bead shape with no dripping. FIG. 3(A) shows the state of bead stacking when upward welding is performed.

It goes without saying that the present invention can be applied to narrow gap welding in general, regardless of MIG welding or MAG welding.

[0018]

[Effect of the invention] According to the narrow gap welding method according to the present invention,
By directing the welding wire bent in a dogleg-shaped zigzag pattern toward the opposing groove walls and welding in alternating distributions, it is possible to weld in all positions, which was not possible with conventional single-layer, single-pass welding. In addition, compared to welding with a straight wire, which is oriented in the same way in advance and distributed welding, by bending the wire and performing distribution welding by oscillating at high speed, it is possible to obtain sufficient penetration, and to It has a large adaptability and forms a flat, non-convex weld bead throughout all positions, resulting in stable welding quality.

[Brief explanation of the drawing]

FIG. 1 is a front view of an example of an apparatus applied to implement the present invention.

FIG. 2 is an explanatory diagram of a welding situation according to an embodiment method.

FIG. 3 is a comparative explanatory diagram of weld bead lamination states according to the method of the present invention and the conventional method.

FIG. 4 is an explanatory diagram of a conventional narrow gap welding method.

FIG. 5 is an explanatory diagram of another conventional narrow gap welding method.

FIG. 6 is an explanatory diagram of a wire feeding state in a conventional narrow gap welding method.

[Explanation of symbols]

1 Narrow gap 3 Wire 3a　Bending wire 4 Arc 8, 8a, 8b weld bead 11 Base plate 12 Slide 13, 14 Bent molded feeding gear 20 Slide block 23 Wire guide cap 27 Wire guide tube 29 Power supply chip

Claims (1)

[Claims] 1. A narrow gap welding method in which a welding wire is passed between a pair of gears and fed into a narrow gap as a bent wire, the welding wire being swung in a direction perpendicular to the wire feeding direction immediately before the gears. A narrow gap welding method characterized in that the bending wire is made to have directionality by moving the bending wire.