JPH06102272B2 - Electronic beam welding start / end processing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for starting and ending electron beam welding performed while continuously supplying a filler wire.

[Conventional technology]

Various methods have been studied in the past for non-filament welding, in which no filler wire is supplied. However, there are almost no study examples of the start and end treatments in electron beam welding performed by continuously supplying the filler wire. This is because, in electron beam welding, usually, the groove of the material to be welded is machined, so the groove precision is good and there is almost no groove gap.
Therefore, it is not necessary to supply the filler wire.

[Problems to be solved by the invention]

However, when a large structure having a long welded joint is to be welded by electron beam welding, if the groove is machined, the cost becomes enormous and the welding cost rises.

Therefore, if the filament wire is continuously supplied to the welded portion and electron beam welding is performed, the allowable range of the groove gap, which was the upper limit of 0.5 mm in non-filament welding, can be expanded to around 3 mm,
Except in special cases, machining of the groove is not required, which can greatly contribute to the reduction of welding cost. However, the start-and-end processing technology for the filler wire supply welding has not been established, and in order to put the filler-wire-supply type electron beam welding into practical use, it is essential to develop the start-and-end processing technology for the welded part.

The present invention has been made to address such a demand, and it is an object of the present invention to propose a method for processing the beginning and end of electron beam welding that can obtain a good weld at the beginning and end of the welded portion. .

[Means for solving problems]

 In the electron beam welding start / end processing method according to the present invention, the start / end processing is performed under the following conditions.

(A) The beam current is gradually increased from when the electron beam is outside the welding start position of the material to be welded, and (b) the beam current is changed when the electron beam reaches the welding start position of the material to be welded. The steady welding beam current is set to 70 to 100%, and at the same time, the feeding of the filler wire is started and the feeding speed of the filler wire is promptly increased to the steady speed. afterwards,
Electron beam welding is performed with a steady welding beam current while feeding the filler wire at a steady speed.

The termination process is performed under the following conditions.

(B) When the electron beam reaches the penetration end position of the material to be welded, the beam current is set to 70 to 100% of the steady welding beam current, and at the same time the feed of the filament wire is stopped, or in the case of full circumference welding , When the electron beam approaches the penetration end position of the material to be welded, the supply of the filler wire is stopped, and when the penetration end position is reached, the beam current is set to 70 to 100% of the steady welding beam current, B) The beam current is set to zero when the electron beam moves out of the welding end position of the material to be welded.

[Work]

In this invention, when the electron beam reaches the penetration start position of the material to be welded, the beam current value is increased so as to reach a predetermined current value, and the feed rate of the filler wire is rapidly increased from the penetration start position. Then, a constant penetration depth is secured from the penetration start position by promptly setting the steady speed. Even at the welding end position of the material to be welded, the beam current value is lowered to a predetermined current value and the feeding speed of the filler wire is set to zero to secure a uniform penetration depth throughout the welded portion. Also, in the case of full-circumferential welding in which the penetration start position and the penetration end position of the material to be welded match, only the start end processing is performed as described above to prevent the welded parts from overlapping at both positions. Just before the penetration end position, only the beam current value is lowered to a predetermined current value without supplying the filler wire.

〔Example〕

FIGS. 1 (a) and 1 (b) show the operation timing of one embodiment of the present invention, and FIG. 1 (a) shows the beam current Ib on the vertical axis and the time on the horizontal axis during welding of the beam current. The timing is shown, and (b) shows the operation timing of the filler wire feeding speed during welding by taking the filler wire feeding speed on the vertical axis and the time on the horizontal axis.

First, the starting end process at the time of electron beam welding will be described.

As shown in FIG. 1 (a) moving, from the time t ₀ when the electron beam is outside of the penetration starting position reaches the time t ₁ of the workpieces raised the beam current Ib, an electron beam workpieces direction When the electron beam reaches the penetration start position of the material to be welded
The slope control of the beam current Ib is performed so that the beam current value It ₁ reaches 70 to 100% of the predetermined welding beam current It when reaching t ₁ .

Also, when the electron beam reaches the penetration start position of the material to be welded
At the same time when t ₁ is reached, as shown in FIG. 1 (b), the feeding of the filament wire is started, and the feeding speed is made to reach a predetermined steady speed V as quickly as possible. When the feeding speed of the filament wire reaches the steady speed V, the steady beam current is passed after t _2.
Weld with It. The time t ₂ is determined by the feeding acceleration time of the filler wire.

Next, the termination process will be described.

The slope control of the beam current Ib and the filler wire feeding speed at the terminal end is started by the beam current Ib starting to drop at the time t ₃ when the electron beam approaches the penetration end position, and the electron beam starts the penetration end position of the workpiece. When the reaching time t ₄ is reached,
The beam current It ₄ is controlled to be 70 to 100% of the steady beam current It.

On the other hand, the feeding speed of the filler wire is controlled so as to quickly reach zero when the electron beam reaches the welding end position t ₄ of the material to be welded.

The reason for setting the beam current value at the penetration start position t ₁ and the penetration end position t ₄ to 70 to 100% of the steady beam current It in the start / end processing is as follows.

Penetration start position arrival time t ₁ also or penetration end position arrival time
If the beam currents It ₁ and It _{4 at} t ₄ are less than 70% of the steady beam current, the penetration depth at the penetration start position or the penetration end position will be insufficient, and there will be too much supply of the filament wire, causing the filament wire to melt. This is because the molten steel becomes unstable and melts down from the bead surface.

FIG. 2 shows a penetration shape (cross section parallel to the welding line direction) when electron beam welding is performed by the above-mentioned start and end processing. As shown in the figure, with respect to the thickness 3 direction of the welded material 1,
It is possible to obtain the penetration 2 having a substantially uniform depth from the penetration start position 4 to the penetration end position 5.

Hereinafter, a specific example of performing electron beam welding according to this embodiment will be described.

〔Concrete example〕

As shown in Fig. 3, the material to be welded has a thickness of 50 mm and a width of 500 m.
The SM50B with a length of 700 mm is used as the upper plate 6, the SM50B with a thickness of 120 mm, a width of 500 m, and a length of 700 mm is used as the lower plate 7, and the distance between the upper plate 6 and the lower plate 7 is 2 mm.
The groove 8 was overlapped with each other, and while being supplied to the filler wire 9, the electron beam 10 was irradiated to weld one surface of the material to be welded.

The welding conditions for this welding are as follows.

Welding conditions in the steady welding area Acceleration voltage: 150KV Beam current: 180mA Welding speed: 30cm / min Filament wire (carbon steel): 1.6mm Filament wire feeding speed: 10.0m / min Welding position: Lateral start processing condition When the welding start position is reached beam current at t _1: 180 mA penetration starting position arrival time period from t ₁ to t _2: 0.5 sec termination condition penetration end position reaches the time t ₄ in beam current: 180 mA t ₃ when the penetration end position reached t Time to ₄ : 0.3 sec Under the above conditions, the upper plate 6 and the lower plate 7 were welded to form the beads 11. After this welding, an ultrasonic test was conducted on the welded portion, but no defect echo was observed.

Moreover, as a result of investigating the penetration depth and the presence or absence of welding defects by adopting a cross section parallel to the welding line, it is found that the penetration shape has a substantially uniform penetration depth from the penetration start position to the penetration end position. No welding defect was observed from the penetration start position to the penetration end position.

When the entire circumference of the material to be welded shown in FIG. 3 is welded by the start-and-end processing shown in this embodiment, the welded portion after the start of penetration overlaps the welded portion before the end of penetration, so that the fusion of the overlapped portion occurs. The metal becomes excessive, causing the molten metal to drop. Therefore, in this case, only the leading edge treatment is performed, and the overlapping welds are controlled only by the beam current lowering without supplying the filler wire in the terminal treatment so that the penetration depth is uniform over the entire circumference. be able to.

〔The invention's effect〕

As described above, according to the present invention, when the electron beam reaches the penetration start position of the material to be welded, the beam current value is increased so as to reach a predetermined current value, and the feed rate of the filler wire is increased from the penetration start position. Is rapidly raised to a steady speed to secure a constant penetration depth from the weld before the end of penetration. Even at the welding end position of the material to be welded, the beam current value is lowered to a predetermined current value and the feed rate of the filament wire is set to zero to ensure a uniform penetration depth throughout the welded portion, so that the filament wire can be continuous. It has an effect that the electron beam welding to be supplied to Further, even in the case of the full circumference welding, since the welded portions do not overlap at the penetration start position and the penetration end position, there is an effect that a continuous and uniform penetration depth can be secured in the entire welded portion.

[Brief description of drawings]

1 (a) and 1 (b) show the operation timing of the embodiment of the present invention, (a) is a beam current timing diagram,
(B) is a timing chart of the feeding speed of the filler wire, FIG. 2 is a sectional view showing a penetration depth according to the above embodiment, and FIG. 3 is a perspective view showing a concrete example welded according to the above embodiment. 1 ... Material to be welded, 2 ... Penetration shape, 6 ... Upper plate, 7 ...
Lower plate, 8 ... Gap, 9 ... Filler wire, 10 ... Electron beam.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Tagane 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Toshinori Matsuo 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Inventor Ichiko Yako Ryoichi Steel Pipe Co., Ltd. 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo

Claims (2)

[Claims] 1. In electron beam welding performed while continuously supplying a filler wire, (a) the beam current is gradually increased from when the electron beam is outside the welding start position of the material to be welded, (b) When the electron beam reaches the penetration start position of the material to be welded, the beam current is set to 70 to 100% of the steady welding beam current, and at the same time, the feed of the filler wire is started and the feeder speed of the filler wire is promptly set to the steady speed. (C) When the electron beam reaches the welding end position of the material to be welded, the beam current is set to 70 to 100% of the steady welding beam current, and at the same time the feeding of the filler wire is stopped. The beam current is set to zero when is moved out of the penetration end position of the material to be welded. 2. In electron beam welding for performing full circumference welding while continuously supplying a filler wire, (a) gradually increasing the beam current from when the electron beam is outside the welding start position of the material to be welded. (B) When the electron beam reaches the penetration start position of the material to be welded, the beam current is set to 70 to 100% of the steady welding beam current, and at the same time feed of the filler wire is started. When approaching the welding end point of the welding material, feeding of the filler wire is stopped, and when reaching the end point of welding, the beam current is set to 70-100% of the steady welding beam current. A method of starting and terminating electron beam welding, wherein the beam current is set to zero when the material to be welded is moved to a position outside the penetration end position.