JPH0333432B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding method, and in particular to a welding method that is suitable for wide grooves, does not cause welding defects, and can perform welding work efficiently in one rare and one pass.

For example, when TIG welding a horizontal groove, if it is done in one rare multiple pass, the number of passes is large, making the setup for each pass difficult and inefficient, and depending on the skill of the welder, defects are likely to occur. .

On the other hand, if one pass is performed using a general time chart as shown in Fig. 1, undercut 2 may occur at the top of groove 1 as shown in Fig. 2, and undercut 2 may occur at the bottom of groove 1. There is a problem in that overlap 4 occurs due to drooping. Moreover, this tendency is particularly noticeable when the groove is wide.

The present invention has been made in view of the above circumstances, with the aim of providing a welding method that can efficiently perform welding work in one rare and one pass without causing weld hole pitting even in the case of wide grooves. be.

Embodiments of the present invention will be described below with reference to the drawings. In the welding method of the present invention, for example, a reference line is set on the center line of a horizontal groove, and the wire is fed in synchronization with the oscillation of only the upper half period of the reference line, and the bead formed by feeding the wire is Overlap (so that the beats overlap continuously)
The vehicle is designed to run forward or reverse as appropriate.

That is, based on the composite oscillation trajectory obtained from the time chart in FIG. 1 (see FIG. 3), the wire feeding pattern is appropriately selected according to the conditions such as the width and depth of the groove in synchronization with the oscillation rate. and a trolley running pattern. As a result, composite oscillation loci as shown in FIGS. 5A and 5B are obtained.

In Fig. 3, _T1 is the upper end stop time of the cart, _T'1 is the lower end stop time, D is the oscillation rate fall time, U is the oscillation rate rise time, and the fourth
In the figure, FT indicates the wire feeding time, and RT indicates the reversal time to prevent wire droplets. Also, the oscillation inclination angles β, β' and the locus in Fig. 5 are as follows:
Bogie speed V, V' and traveling time VT, VT' and D,
Can be selected by combination of OD. Therefore, T ₁ =T′ ₁ ,
If D=D, then when V>V', the truck moves forward by keeping constant β by the difference between V and V', while V=V', U>
If it is OD, the cart moves forward by the difference between U and D.

The wire feeding control described above is performed as shown in FIG. That is, a comparison amplifier 7 compares a voltage proportional to the amplitude of the oscillator emitted from the potentiometer 5 and a reference voltage emitted from the reference line setter 6.
When the voltage is higher than the reference value, a signal is output to the controller 8, and furthermore, signals of the upper and lower stop positions of the oscillation rate from the position detector 9 are input to the controller 8, and from the controller 8 to the wire feed motor 10. Controls the wire feeding time by issuing a command signal. Note that a current setting device 11 is installed between the controller 8 and the motor 10 as shown by the imaginary line.
If provided, it can also be performed in MIG welding.

On the other hand, the running of the bogie is controlled as shown in FIG. That is, the oscillation upper stop/completion signal from the upper and lower position detectors 12 and 13 and the oscillation lower stop/completion signal
The completion signal is determined by the up/down signal discriminator 14, the signal is sent to the controller 15, and the controller 15 outputs a command signal to the bogie motor 16.

Therefore, when a horizontal groove is welded using the wire feeding pattern and the trolley running pattern as described above, the molten metal above the reference line is moved downward by gravity as shown in FIG. hanging down to the first
Coupled with the melting and solidifying effect due to the pulse effect of the welding current shown in the figure, uneven thickness can be prevented (h ₁ =
h ₂ ), a sound bead 3 without undercuts or overlaps is formed by one-rare one-pass welding. In particular, since the beat 3 wraps above the reference line, the line is advantageous for wide grooves.

In the embodiment described above, the wire was fed only above the groove center line, but the wire may also be fed appropriately below the center line. In other words, in this case, the reference line is set below the center line, as shown by the two-dot chain line in FIG. Of course, it can also be set on the upper side. In other words, the point is to increase the amount of wire fed above the center line rather than below it. Also, without changing the torch center position and amplitude,
The wire feeding time may be made variable by electrically applying plus and minus voltages to the reference line. In other words, the wire can be turned on and off at any position above or below within the groove.

Next, a case will be described in which the welding method of the present invention is applied to a horizontally fixed pipe in all positions.

That is, FIG. 9 shows the development of a general pool in the vertically descending portion of a horizontal fixed pipe, and if the pool leading angle β ₁ exceeds a certain value, welding defects such as poor fusion will occur. In addition, the appropriate β ₁ changes from moment to moment depending on the groove base shape and welding posture. Particularly, defects are likely to occur in the portion indicated by reference numeral 17 in FIG. Therefore, by applying the above-mentioned embodiment and feeding a large amount of wire to the 18th part of the groove 1, and reducing the amount of wire feeding to the 19th part to zero or a minimum, the wire can be directly fed to the base material of the 17th part. An arc is generated and sound welding can be performed.

It should be noted that the present invention is not limited only to the above-mentioned embodiments, and it goes without saying that various changes may be made without departing from the gist of the present invention.

As explained above, according to the welding method of the present invention, the synthetic oscillation of a repeated pattern of horizontal forward movement, inclined upward backward movement, horizontal backward movement for a distance shorter than the horizontal forward movement, and inclined downward forward movement while rotating the bogie forward and reverse as appropriate , and while the wire is moving within the groove based on the synthetic oscillation rate, more wire is fed to one side of the groove reference line than to the other side. It is possible to form a sound bead without uneven thickness without causing welding defects such as cuts, overlaps, or weld defects, and is particularly advantageous for wide groove welding. In addition, since groove welding can be performed in one rare and one pass, work efficiency is improved. Furthermore, conventionally, when performing tilt oscillation, a mechanically treated dedicated head was used, but since the present invention is electrically controlled, one head can easily be used for both horizontal and vertical directions, making it easier to construct tilt joints. becomes possible. Furthermore, the main current is not affected by the classification of direct current or alternating current, nor is it affected by the feeding direction of the wire.

[Brief explanation of the drawing]

Fig. 1 is a time chart of the conventional welding method, Fig. 2 is an explanatory diagram of welding defects in the case of the conventional welding method, Fig. 3 is a diagram showing the locus of general mechanical oscillation, and Fig. 4 is a diagram of the present invention. 5A and B are explanatory diagrams showing the locus of mechanical oscillation obtained by the time chart of FIG. 4, and FIG. 6 is a time chart showing the welding method of the present invention. Fig. 7 is a control block diagram of the wire in the welding method of the present invention, Fig. 8 is a control block diagram of the running of the same bogie, and Fig. 9 is a general diagram of the vertical downward welding part. FIG. 10 is an explanatory diagram when the present invention is applied to an all-position horizontal fixed pipe as viewed from the X direction arrow in FIG. 9. 1...Bevel, 3...Beat, 10...Wire feed motor, 16...Dolly motor.

Claims (1)

[Claims] 1 Properly rotate the trolley forward in synchronization with the oscillation rate,
A composite oscillation is formed of a repeated pattern of horizontal advance, inclined upward retreat, horizontal retreat of a distance shorter than the horizontal advance, and inclined downward advance while reversing, and the groove reference is set while the wire is moving within the groove based on the synthesized oscillate. A welding method characterized by feeding a larger amount of wire to one side of the line than to the other side.