JP2912150B2 - Vertical TIG welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical TIG welding method, and more particularly to a vertical TIG welding method for a vertical joint of a side plate having a bottom plate easily and without causing welding defects.

[0002]

2. Description of the Related Art In a welding operation of a tank or the like, a vertical joint of a side plate may have a bottom plate.
In the case of performing welding, there is a problem that a torch or other welding machine parts interfere with the bottom plate, so that an unwelded portion is formed at a welding start portion.

That is, as shown in FIG. 1, welding is generally performed on a vertical joint of a side plate 15 having a bottom plate 16 with a torch angle being horizontal or slightly upward. In this case, the torch 2 and the parts of the welding machine interfere with each other, and a welding residue 3 is generated. In the figure, reference numeral 1 denotes a groove bottom.

Conventionally, automatic TIG welding has been carried out to solve this problem by covering the remaining welding portion by covered arc welding or jacking up the side plate until the bottom plate does not interfere.

[0005] However, in the former case, defects are liable to occur due to the formation of a joint at the welding, and the quality of the joint is poor because the characteristics of the weld metal by coated arc welding are generally inferior to those of the TIG weld metal. Had a problem. On the other hand, the latter has a problem that the man-hour for jacking up is significantly increased.

The present invention solves the above-mentioned disadvantages of the prior art,
When welding tanks, etc., without jacking up
Further, it is an object of the present invention to provide a welding method in which a vertical joint of a side plate having a bottom plate can be completely eliminated by automatic TIG welding without leaving a weld joint portion, and a residual welding portion at a welding start portion can be completely eliminated.

[0007]

As a means for solving the above-mentioned problems, the present invention provides a vertical joint of a side plate having a bottom plate by TIG welding, in which the torch angle is lowered by 10 to 45 °. Using a magnetic field generator having an iron core passing through the coil and a coil current control unit, a DC magnetic field in a direction substantially perpendicular to the welding line and the direction of the arc and in a direction of deflecting the arc upward is generated near the arc point. A vertical TIG welding method characterized in that an arc generated downward from the torch is deflected upward by simultaneously generating an upward force on the molten metal to prevent the bead from dripping. I do.

[0008]

The present invention will be described below in more detail.

As described above, when performing vertical automatic TIG welding, the torch angle is generally set to be horizontal or slightly upward as shown in FIG. 1, but in this torch posture,
Since the torch and other parts interfere with the bottom plate,
Occurs. On the other hand, in the present invention, the torch 2 is turned downward as shown in FIG.

[0010] However, if the torch angle 11 is less than 10 °, an unwelded portion occurs due to interference between the torch and the bottom plate,
When the torch angle 11 exceeds 45 °, it is difficult to secure a space for feeding the wire. Therefore, the torch angle needs to be in the range of 10 ° to 45 °.

However, when the torch angle is set to the downward direction, the direction of the arc is also downward, and the arc force acts downward on the molten pool, so that the bead drips, causing a poor bead shape or a severe case. Makes welding impossible.

For this reason, in the present invention, a magnetic field generator having an iron core passing through the coil and a coil current control unit is used, and the welding line and the arc are substantially perpendicular to each other and the arc is deflected upward. A magnetic field in the direction is generated near the arc point. When the arc is deflected by this magnetic control, the molten metal is prevented from receiving a downward force due to the arc force, and by applying an upward force to the molten metal, the bead can be prevented from dripping.

The configuration of the present invention will be described with reference to the drawings. FIG. 4 shows an apparatus for applying a magnetic field to an arc.
This magnetic field generator includes an iron core 6 passing through a coil 7 and a coil current control unit 5. When a coil current flows through the coil 7 by the coil current control unit 5, a magnetic field is generated in a direction indicated by 9. At this time, a welding current (arc) 8 having a tungsten electrode as a negative electrode receives an upward force. Therefore, the arc can be deflected upward.

FIG. 3 is a sectional view of the weld metal when FIG. 4 is viewed from the left side. Magnetic field 4 generated from coil and molten metal 10
From the welding current 13 (dashed arrow) flowing through the
0 receives a force in the direction of 14 (solid arrow). The lower part of the molten metal receives a force in the direction pressed against the base material surface, and receives an upward force from the central part to the upper part. Therefore,
By applying magnetism to the arc and the molten metal by the magnetic field generator shown in FIG. 4, the downward arc force is reduced,
In addition, the upward force acts on the molten metal to prevent the bead from dripping.

In this welding method, the minimum magnetic force required to obtain a good bead shape without sagging is 10 gauss when the torch angle is 10 ° and the welding current is 200 A. When the torch angle is made larger than 10 °, a larger magnetic force is required.

According to such a welding method, it is possible to perform automatic TIG welding that eliminates a remaining welding portion at a welding start portion without causing a torch or other welding machine parts to interfere with a bottom plate. Further, it is possible to obtain a welded joint having no welding joint.

The present invention is effective for a welding start site where a torch or other welding machine parts interfere with the bottom plate.
The welding at the joint portion where the bottom plate does not interfere may be performed under similar conditions, or may be performed with the torch horizontal or slightly upward.

It goes without saying that other welding conditions are not particularly limited. For example, welding conditions such as welding current, voltage, and speed are appropriately determined, and wire feeding is also possible. The groove shape and dimensions are also determined according to the required joint design.

Next, an embodiment of the present invention will be described.

【Example】

A groove having the shape and dimensions shown in FIG. 5 is provided on the side plate,
A vertical welding (four layers) of a vertical joint having a bottom plate was subjected to a welding experiment under the conditions shown in Table 1. For comparison, experiments were performed with and without magnetic control (Experiment 1: Example of the present invention) and without magnetic control (Experiment 2: Comparative Example). In addition, the welding start part and the inside of the groove | channel above this were also constructed on the same welding conditions.

The experimental results are shown in FIG.
When there was no magnetic control, the bead dripping was remarkable in the second layer, the bead shape was protruded from the center, and the molten metal dripped off in the third and subsequent layers, making welding impossible. On the other hand, in the case of magnetic control, welding was possible without causing sagging of the bead up to the fourth layer. It was also effective in the case of vertical welding in which the torch angle was slightly downward or upward from 25 degrees. Since the torch was tilted in this way, the torch and other welding machine parts could be installed without interfering with the bottom plate.

[0022]

[Table 1]

[0023]

As described above, according to the present invention,
When welding tanks, etc., automatic TIG welding can be performed to eliminate the remaining welding at the start of welding without the torch or other welding machine parts interfering with the bottom plate, eliminating the need for the step of jacking up the side plates. Become. Thereby, the construction period for construction can be significantly reduced. Further, a high-quality welded joint having no welding joint can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a positional relationship between a torch and a workpiece when welding is started with a torch angle being horizontal.

FIG. 2 is a diagram illustrating a welding situation when the torch is tilted downward.

FIG. 3 is a diagram illustrating a welding situation when a torch is tilted downward to perform magnetic control.

FIG. 4 is a diagram illustrating an example of a magnetic field generator.

FIG. 5 is a diagram illustrating a groove shape of a workpiece in an embodiment.

FIG. 6 is a photograph showing a metal structure of a cross section of a welded joint obtained in an example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 groove bottom 2 torch 3 remaining welding part 4 magnetic field 5 coil current control unit 6 iron core 7 coil 8 arc 9 direction of magnetic field 10 molten metal 11 torch angle 12 electrode 13 direction of welding current 14 direction of force applied to molten metal 15 Side plate 16 Bottom plate 17 Weld metal

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadashi Muneyuki 1-2, Nakahara, Miya-machi, Toyohashi-city, Aichi Pref. Town character Nakahara 1-2, Kobe Steel Ltd. Toyohashi FA / Robot Center (72) Inventor Tsuneyoshi Takewaki 8-19-20 Higashisuna, Koto-ku, Tokyo No. 19-20 (72) Inventor Noriaki Yoshikawa 8-19-20 Higashisuna, Koto-ku, Tokyo (56) References JP-A-60-255269 (JP, A) JP-A-57-31473 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B23K 9/08 B23K 9/02 B23K 9/167

Claims (2)

(57) [Claims] When a vertical joint of a side plate having a bottom plate is vertically welded by TIG welding, the torch angle is set to 1 downward.
A DC magnetic field in a direction substantially perpendicular to the direction of the welding line and the arc and deflecting the arc upward, using a magnetic field generator having an iron core passing through the coil and a coil current control unit, in addition to 0 to 45 °. Is generated in the vicinity of the arc point, thereby deflecting the arc emitted downward from the torch upward, and at the same time, generating an upward force on the molten metal to prevent the bead from dripping.
Welding method. 2. The method according to claim 1, wherein the strength of the magnetic field is 10 gauss or more.