JPS6037191Y2 - Sliding type dowel for welding - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sliding welding dowel that can be adapted to various downward to upward welding positions, and particularly relates to a dowel applicable to inclined welded joints.

A typical example of an inclined joint is a butt circumferential joint for fixed pipes, but in this case the angle of inclination relative to the vertical line changes sequentially, and in particular electroslag welding or electrogas arc welding is performed from the inside of the pipe. In this case, you will encounter various difficulties.

That is, when laying steel pipes, for example, as water pipes, a buried piping method is generally employed.

However, in the case of underground pipes, the on-site welding is performed while the pipe bodies are butted together in the excavated area, so it is not possible to apply welding equipment from the outer circumference, so welding equipment is brought inside the pipe and welds one layer on each side from the inner side. has become the norm.

In this case, a fixed abutment is applied to the back side of the groove, that is, the outer circumference of the pipe, and a sliding abutment is applied to the front side of the groove, that is, the inner circumference of the pipe, to prevent the molten metal from dripping. However, electroslag or electrogas arc welding is performed.

FIG. 1 is a conceptual diagram showing chronological changes in such upward welding, and the arrow indicates the direction of welding progress.

In the figure, 1 is a bevel, 2 is a fixed type rest, 3 is a sliding type rest, and 4
5 is a welding torch, 5 is a molten pool, and 6 is an arc, which are designated as A, HO, and C, respectively, depending on the position of the molten metal level in each pool 5.

In electrogas arc welding, when the welding torch 4 is oriented approximately vertically (corresponding to the mouth in Figure 1), the arc 6 is generated approximately perpendicularly to the surface of the molten metal.
When the arc 6 is inclined with respect to the molten metal surface, the arc 6 is also generated at an angle, which tends to cause excessive penetration or insufficient penetration.

For example, the position A is for welding in a downwardly inclined position, and the detailed view is as shown in FIG. Therefore, the arc heat mainly affects the metal 3 side.

In other words, (1) high-temperature arc columns and droplets are generated mainly toward the front side of the groove, and (2) high-temperature molten metal and molten slag flow toward the weld metal 3 as shown by the arrow, and are generated toward the groove surface side. However, as a result of phenomena such as (3) solidification of molten metal progressing quickly on the bottom side of the groove, which tends to lead to deposition,
(I) Penetration of the base metal becomes abnormally large on the front side of the groove,
An undercut occurs, and (■) on the other side of the bottom of the groove,
Penetration of the base material is insufficient, and overlapping is likely to occur.

In contrast to these positions, exactly the opposite phenomenon occurs and also results in a defective joint.

In this specification, for convenience, the position of the mouth will be referred to as upright, and the position thereof will be referred to as upward.

Further, in the figure, 9a is a cooling water introduction passage, 9b is a cooling water discharge passage, and 10 is a shielding gas supply passage.

As a means of improving such uneven penetration, we have already proposed Japanese Patent Application Laid-open No. 50-112246 and No. 53-14025, etc., and established a technology to deflect the arc directly downward using a magnetic field. .

As a result, in the region where the central angle θ≦150 degrees in Fig. 1, electrogas arc welding can be performed without the above-mentioned problems regarding penetration, and the high efficiency can be fully enjoyed. There is.

However, it was not possible to completely deal with the occurrence of undercuts in a downwardly tilted position, and further investigation was required.

The present invention has been made based on these four improvements.A shallower molten slag relief groove is formed on both sides of the weld bead forming groove formed along the sliding direction of the metal, and the relief groove is In cases where we have come to provide a sliding butt whose groove width is gradually reduced over the entire length or part of the relief groove, and the welding position changes continuously as shown in Figure 1. Even though
A uniform and undercut-free weld bead was provided over the entire weld line.

In general, in electrogas arc welding, the distance between the sliding dowel and the torch (in the welding line direction) is almost constant regardless of the welding position, and this means that the distance between the sliding dowel and the torch (in the welding line direction) is almost constant regardless of the welding position. It is also reflected in relative positional relationships.

Moreover, the wire extension is also kept almost constant.

Therefore, the distance (in the welding line direction) between the sliding dowel and the wire tip or arc column hardly changes regardless of the welding posture.

On the other hand, since the liquid level of the welding pool tends to be approximately horizontal, the angle between the liquid level and the sliding abutment changes as the attitude changes, as seen in FIG.

Therefore, looking at the welding metal 3 in Fig. 1, as the welding position changes in the order of downward E vertical opening → upward, as shown by the cross hatching at the part in contact with the molten pool 5, the cross hatching The ching portion is also gradually moving (changing) upward.

Figure 3.4 shows these situations in more detail.
Figure 3 is a sectional view of the downward posture corresponding to Figure 1A,
The figure shows a sectional view in an upward position corresponding to FIG. 1, and in each figure, 11 is a shielding gas guide portion, and 12 is a weld bead forming groove.

That is, in the attitude shown in FIG.
At the same time, the molten slag is concentrated at the position indicated by A (i.e., approximately in the center of the welding metal 3), so if you do not mind removing this slag, use the undercut described above. occurs.

On the other hand, in the attitude shown in FIG.
Since the molten slag is held at the upper side of the slag and concentrated at the position indicated by B, there is no need to create a device to allow the slag to escape from the stopper 3.

From this point of view, when continuously upward welding a circumferential joint as described in Figure 1, the role of the sliding weld changes between the downward position and the upward position. I discovered something.

In other words, the weld bead forming groove for adjusting the shape of the weld bead needs to be formed in a substantially constant shape in the sliding direction of the weld, but it is possible to form a slag relief groove on the lower side of the weld. It has been found that this necessity gradually decreases as one moves upwards in the deposit.

Therefore, the present invention adopts a configuration in which molten slag relief grooves are formed on both sides of the weld bead forming groove, and the groove width of the relief groove is gradually reduced over the entire length or part of the length. I ended up doing it.

Figure 5 is a front view of the metal that satisfies the above requirements as seen from the melt pool side, Figure 6 is a partially cutaway side view, Figure 7 is a bottom view, and Figures 8 to 10 are the same as Figure 5. ■-■ line, IX-
It is a sectional view seen from the IX line and the XX line.

In these figures, 13 is a molten slag relief groove;
In this example, the width is approximately the same from the lowest end to the center, and then the width gradually decreases until it reaches a position approximately 3 cm high, and finally disappears.

However, if necessary, it is also possible to start reducing the groove width from the bottom end, or to continue the groove until it reaches the top end.

Further, the degree of reduction of the groove width is shown in a straight line in FIG. 5, but may be curved.

In the figure, the depth of the groove 13 is not changed, but when the amount of molten slag is large, the lower side may be made deeper, and as the groove width is reduced, the depth may be gradually made shallower.

In other words, as long as a configuration is adopted in which the ability to release molten slag is increased on the lower side and the ability is decreased toward the upper side, the above-mentioned reduction process is continuous (tapered).
Whether it is stepwise or stepwise, it satisfies the structure of the present invention.

Since the configuration of the present invention is as described above, the effects as summarized below can be obtained.

(1) When applied to a weld line where the welding position changes sequentially from downward to vertical to upward, the downward position has a large slag release effect and can prevent undercuts, and can be applied to all positions. A good joint can be obtained throughout.

(2) Therefore, even if applied to welding lines where there is no change in posture,
It is possible to demonstrate the slug release function according to each posture,
Extremely versatile.

(3) The bead shape itself is formed with a constant width.

[Brief explanation of drawings]

Figure 1 is a conceptual diagram showing the concept of a circumferential joint in chronological order, Figure 2 is a detailed diagram showing a part of it, and Figures 3 and 4 are fragmentary cross-sectional views of main parts showing the state of the molten pool in each posture. , Fig. 5 is a front view showing the coin of the present invention, Fig. 6 is a partially cutaway side view, and Fig. 7 is a partially cutaway side view.
The figure is a bottom view, and FIGS. 8 to 10 are sectional views. 3... Sliding type dowel, 5... Molten pool, 12... Weld bead forming groove, 13...
- Molten slag relief groove.

Claims (1)

[Scope of claim for utility model registration] (↑) A metal fitting that slides along the surface of the base material to be welded,
Shallower molten slag relief grooves are formed on both sides of the weld bead forming groove, which is formed with approximately the same width in the sliding direction of the gold, and the groove width of the relief groove is set to the full length or a part of the length of the relief groove. A sliding dowel for welding, characterized in that it is gradually reduced in size over a period of time. (2) Scope of Utility Model Registration Claim Paragraph 1 states that the groove width of the relief groove is changed so as to gradually become narrower from the center of the stopper toward one end of the stopper; is a winning that is structured so that there is no escape groove. (3) In paragraph 1 or 2 of claims for utility model registration,
A dowel with a shield gas outlet attached to the end of the dowel on the side where the groove width of the relief groove becomes narrower. (4) Utility model registration Claims 1, 2, or 3 describe a welding member applied to a welded joint where the contact angle between the liquid level of the molten metal pool and the welding member changes as welding progresses. .