JPH0635071B2 - 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, the groove of the material to be welded is usually 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 technique in 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 technique for the welded portion.

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]

The electron beam welding start and end treatment methods according to the present invention are: (a) gradually increasing the beam current from when the electron beam is outside the welding start position of the workpiece, and (b) the electron beam The beam current is set to 10-70% of the steady welding beam current when reaches the penetration start position of the material to be welded, and at the same time the feed of the filler wire is started, and (c) the feed rate of the filler wire reaches the steady speed. At that time, the beam current is changed to 80 to 100% of the steady welding beam current, and then the electron beam welding is performed at the steady beam current while feeding the filler wire at the steady speed.

The terminal treatment is (a) When the electron beam approaches the welding end position of the material to be welded, the beam current is reduced, and when the beam current falls from less than 100% to 80% of the steady beam current, the filler wire (B) When the electron beam reaches the welding end position of the material to be welded, the beam current is set to 10 to 70% of the steady welding beam current, and at the same time, the feed of the filler wire is terminated. (C) When the electron beam moves out of the penetration end position of the material to be welded, the beam current is set to zero to end the welding.

[Action]

In the present invention, the start and end processing is performed by controlling the operation timing of the filler wire in accordance with the rise and fall of the beam current at the start of welding of the material to be welded and at the end of welding.

〔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 operation on welding of the beam current with time on the horizontal axis. The timing is shown, and (b) shows the operation timing of the filler wire feed rate at the time of welding by taking the filler wire feed rate on the vertical axis and taking 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), the beam current Ib is increased from the time t ₀ when the electron beam is outside the welding start position t ₁ of the workpiece, and the electron beam is moved toward the workpiece. When the electron beam reaches the penetration start position t ₁ of the material to be welded, the beam current value It ₁ is 10 to the predetermined welding beam current It.
The slope control of the beam current Ib is performed so as to reach 70%.

At the same time when the electron beam reaches the penetration start position t ₁ of the material to be welded, the feeding of the filler wire is started as shown in FIG. 1 (b). When the feeding speed of the filament wire increases and the feeding speed reaches the steady speed V _t , the current value of the beam current Ib at t ₂
Raise It ₂ to reach 80-100% of the steady beam current It.

This is because if the beam current value It ₂ is not increased in this way, the filament wire will be over-fed and the molten metal will drip from the front beam, and at the same time stable fusion of the filament wire will become difficult.

After that, electron beam welding is performed with a steady welding beam current It while feeding the filler wire at a steady steady speed V _t .

Next, the termination process will be described.

The slobe control of the beam current Ib and the filament wire feeding speed at the terminal end has an inverse relationship with the slobe control at the starting end.

That is, when the electron beam approaches the penetration end position, the beam current Ib starts to decrease, and the beam current value It ₃ changes from less than 100% to 80% of the steady welding beam current It at a time t ₃ The feed rate is started to decrease, and when the electron beam reaches the welding end position of the material to be welded, the feed rate of the filler wire becomes zero at t ₄ . At this time t ₄
The current value It ₄ of the beam current Ib is 1 of the steady beam current It.
The descending control is performed so as to be 0 to 70%.

FIG. 2 shows a penetration shape (cross-section parallel to the welding line direction) when electron beam welding is performed by performing the above-mentioned start and end processing.
Shown in (a) and (b). (a) shows the case where the starting position and the ending position of the penetration are at the end of the welded material 1, and (b) shows the starting position and the ending position of the penetration are inside from the end of the welded material 1. Indicate the case. As shown in the figure, the penetration shape 2 in the penetration start section and the end section has a slope with respect to the plate thickness 3.

The following reasons were a beam current It ₄ of penetration starting position reaches the time t ₁ the beam current It ₁ and penetration end position reaches the time t ₄ and 10% to 70% of the steady-state beam current It in the starting and end processing . When the beam currents It ₁ and It ₄ are less than 10% of the steady welding beam current It, the beam holes are not sufficiently formed in the penetration start section and the end section, and it becomes difficult to stably supply the filament wire. Further, if the beam currents It ₁ and It ₄ exceed 70% of the steady beam current It, the supply amount of the filament wire to the formed beam hole will be insufficient, and the surface beam will largely collapse.

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

[Specific Example 1] As shown in FIG. 3, the material to be welded has a thickness of 50 mm and a width of 5 mm.
SM50B with a length of 00m and a length of 700mm is used as the upper plate 4, and the thickness is 12
The SM50B having a width of 0 mm, a width of 500 mm, and a length of 700 mm is used as the lower plate 5, and a groove gap 6 of 2 mm is provided between the upper plate 4 and the lower plate 5 so as to be superposed. Welded all around. At the time of this welding, the start and end processing was performed for each circumference.

The welding conditions for this welding are as follows.

Welding conditions in steady welding area Acceleration voltage: 150KV Beam current: 180mA Welding speed: 30cm / min Filament wire (carbon copper): 1.6mm Filament wire feeding speed: 10.0m / min Welding position: Lateral start processing condition Penetration start position time from arrival time t ₁ until t _2: 8 sec penetration starting position reaches the time t ₁ in the beam current: 60 mA t ₂ beam in at a current: wire feeding rate in 180mA penetration starting position at arrival time t _1:
Wire feeding speed at 0 m / min t ₂ : 10 m / min Note that the acceleration voltage and welding speed from the time t ₁ to t ₂ when the penetration start position is reached are constant at 150 KV and 30 cm / min, respectively, and the beam current and filament wire The feed rate was increased linearly.

Termination processing time from t ₃ o'clock to the penetration end position t ₄ time: 8 sec Beam current at t ₃ o'clock: 180 mA Beam current at penetration end position t ₄ 40 mA t ₃ wire feed speed: 10m / min Wire feeding speed at time t ₄ when the penetration end position is reached: 0
m / min The acceleration voltage is 150 KV and the welding speed is 30 cm / min.

Under the above conditions, the entire circumferences of the upper plate 4 and the lower plate 5 were welded to form the beads 9. After welding, an ultrasonic test was conducted over the entire welded area, but no defect echo was observed.

Further, a cross section parallel to the welding line direction was sampled, and the penetration depth and the presence or absence of welding defects were investigated. The shape of the penetration is as shown in FIG. 4, and the penetration 2 in the penetration start section 10 and the penetration end section 11 of each circumference is almost the same as the penetration in the steady welding area, and good results are obtained. Was given. Further, no welding defect was observed in the penetration start section 10 and the penetration end section 11.

[Specific Example 2] Welding was performed under the same conditions as in Specific Example 1 except for the material to be welded and the steady-state electron beam welding conditions, but the start and end treatment conditions were changed as shown below.

Starting edge processing condition Time from arrival of penetration start position t ₁ to t ₂ o'clock: 7 sec Beam current at penetration start position t ₁ : 90 mA Beam current at t ₂ o'clock 145 mA At penetration start position t ₁ Wire feeding speed: 0
Wire feeding speed at 10 m / min t ₂ ： 10 m / min Time from terminating condition t ₃ to arrival time point t _{4 of} penetration: 7 sec t ₃ Beam current: 160 mA Time to reach penetration end point t ₄ Beam current at time: 60
Wire feeding speed at mA t ₃ o'clock: 10 m / min Wire feeding speed at t ₄ o'clock when the penetration end position is reached:
0m / min Under the above conditions, the entire circumference of the material to be welded was welded and an ultrasonic test was conducted over the entire welded area, but no defects were found and the penetration start and end sections of each circumference Both were free from defects and a sufficient penetration depth was secured.

〔The invention's effect〕

As described above, according to the present invention, the filler wire is continuously processed by performing the start and end processing for controlling the feeding speed of the filler wire in accordance with the rising and falling timings of the beam current in the welding start section and the end section of the material to be welded. Practical application of electron beam welding can be achieved.

In addition, the penetration depths of the penetration start section and the end section can be satisfactorily obtained, and particularly in the entire circumference welding, there is an effect that a penetration depth equivalent to that of the steady portion can be obtained.

[Brief description of drawings]

1 (a) and 1 (b) show operation timings of an embodiment of the present invention, (a) is a timing diagram of beam current, (b) is a timing diagram of filament wire feeding speed, and FIG. 2 (a), (b) is a cross-sectional view showing the penetration depth in each of the above embodiments, FIG. 3 is a perspective view showing a concrete example welded by the above embodiments, and FIG. 4 is a third view.
It is a welding part sectional view of the to-be-welded material shown in the figure. 1 ... Material to be welded, 2 ... Penetration shape, 4 ... Upper plate, 5 ...
Lower plate, 6 ... groove gap, 7 ... filler wire, 8 ... electron beam, 10 ... penetration start section, 11 ... penetration end section.

Front page continuation (72) Inventor Akira Tagane Nihon Steel Pipe Co., Ltd. 1-2-1, Marunouchi Chiyoda-ku, Tokyo (72) Inventor Toshinori Matsuo 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Inventor Yatsuko Ichiryo 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Tube Co., Ltd.

Claims (1)

[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 workpiece, and (b) The beam current is 10 to 70% of the steady welding beam current when the electron beam reaches the welding start position of the material to be welded.
At the same time, the feeding of the filler wire is started, and (c) when the feeding speed of the filler wire reaches the steady speed, the beam current is set to 80 to 100% of the steady welding beam current. When the welding current approaches the welding end position, the beam current is reduced, and when the beam current reaches a value of less than 100% to 80% of the steady welding beam current, deceleration of the filament wire feed speed is started. ) When the electron beam reaches the penetration end position of the material to be welded, the beam current is 10 to 70% of the steady welding beam current.
At the same time, the supply of the filler wire is finished, and (f) the beam current is made zero when the electron beam moves outside the welding end position of the material to be welded. Processing method.