JPS58205681A - Multi-layer welding method - Google Patents

Abstract

PURPOSE:To perform accurately automatic copying multi-layer welding in a groove with multi-layers having a weld layer composed of plural passes, by inverting a torch oscillating in the groove at a location of a prescribed oscillating width after it is inverted at one wall face. CONSTITUTION:When multi-layer welding is performed in a groove with a welding torch being advanced along a welding line and oscillated in the direction of the width of groove while the interval between the torch and groove is maintained constantly, beads (a) and (b) of the 1st and 2nd layers are formed by performing the welding while the copying of the torch in the direction of the welding line is performed by catching arc signals of both end parts R and L of the groove. In the 3rd bead (c), the torch is oscillated toward one end R of the groove, inverted after detecting a position at a prescribed height A1, oscillated by a preset width l1 toward the other end L of the beveling from the inverted position A1, and again inverted toward the R at a position B1. The bead (c) of the 3rd layer is formed by alternately inverting the torch at points A2, B2,... in the same way.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-layer welding method for automatically welding base materials in multiple layers while following the bath tangent direction of the base materials.

In automatic arc welding, the arc is stabilized by keeping the distance between the torch tip and the base metal constant by detecting changes in arc characteristics while swinging the torch in the width direction of the groove. In addition, the torch groove tracing control is performed in which the change in the position of the torch in the height direction is used for reversal control of the torch swing, and the torch follows the direction of the weld line of the base metal.

However, as shown in Figure 1, as the plate thickness of the base metals 1 and 1' increases and the groove width increases, the number of bath contacts and grooves in multilayer welding increases, and one layer must be welded in multiple passes. You will have to weld it. That is, in Figure 1, three layers 5/'p are formed between 1°1' of the base material.
In this example, a, b, and c are welded at

d and e are beads generated by valley passes from 1 pass to 5 pass. As shown in the figure, welding of the first fusion point and the second layer requires only one pass each, but since the groove width of the third layer becomes wider, welding at l/P speed is difficult due to the shape of the weld bead and penetration. I can't do it, so I'm 3-no-yasu (c.

Welding of d and e) is required.

Therefore, during welding of the third layer, that is, the third pass where bead C is formed and the fourth pass where bead d is formed, the swinging torch cannot be reversed on the left and right wall surfaces of the groove. Conventional methods have had the problem of not being able to perform torch tracing control.

This invention utilizes the above-mentioned four points to reduce the swing of the torch to a constant width even when the groove width is wide and one weld layer is welded with a large number of nozzles. This method provides a multi-layer welding method that can be reversed by moving the torch along the welding line while keeping the distance between the torch and the groove constant, while also swinging the torch in the width direction of the groove. In a multilayer welding method in which a groove is welded while the groove is welded, a torch that swings within the groove in its width direction is set in advance to the inverted position of the torch when it is inverted on one wall surface of the groove. Determining the reversal position of the torch on the other side of the groove from the rough six movement width of the torch,
The present invention is characterized in that when the torch reaches the inverted position, its swinging motion is reversed, and welding is performed while repeating such a reversing operation.

Next, the present invention will be described with reference to embodiments and drawings.

FIGS. 2(a), 2(b), and 2(c) are explanatory diagrams showing the principle of the present invention. 111th layer bead a and 2nd layer bead b
This is done by swinging the torch using a conventional method, capturing arc signals at both ends of the breast tip, and welding while tracing the groove in the welding line direction of the torch.

Next, in the welding of the third layer, since the groove width becomes large as described above, welding cannot be performed using conventional groove tracing control based on IA. Therefore, as the torch oscillates in the direction R of one end of the groove, the distance between the tip of the torch and the base material is kept constant, as shown in Fig. 2 (0), where the torch oscillates in the direction shown by the solid line. The control raises the torch along the groove wall,
When the value indicating the position of the torch in the height direction reaches the reversal reference value of the swinging direction, the swinging of the torch is reversed in the direction of the other end of the bevel at point A, and the swinging is reversed to the swinging reversal position A1. Please note the following. Next, the torch is reversed in the L direction, and the torch is swung 11h-a in the L direction by a preset width t with respect to the swing reversal position A1, and the torch is swung again at point B1. One end of is reversed in the R direction. Thereafter, use the same method to reverse the torch at point A2, and
By repeating the operation of swinging in the L direction by a width of 2 and then reversing in the R direction at point B2, the torch is copied and a weld bead is formed. Note that FIG. 2H is a diagram showing the amount of change in the height direction of the welding torch.

FIG. 3 shows an example of a control circuit for implementing the present invention. In Fig. 3, 1°1' is the base material, 2
is an electrode, and 3 is a torch. The torch 3 is swung in the width direction of the groove, and at this time, a change in the distance between the tip of the electrode 2 and the groove wall surface 1' of the base material 1, 1' is detected by, for example, a welding voltage detector 4. be done. The value detected by the welding voltage detector 4 is compared with the reference value of the voltage reference value setter 5 by the differential amplifier 6, and the value is transmitted to the Y-axis block via the Y-axis motor controller 7 so that the deviation is O. The Y-axis motor 9 attached to the motor 8 is controlled. As a result, the electrode 2 is connected to the base materials 1, 1
The groove wall surface 1'' is swung along the groove wall surface 1'' while keeping the distance to the groove wall surface 1'' constant at all times.

The amount of change in the height direction of the torch 3, which rotates and swings in this manner, is outputted as an l·-te height position signal 11 from the Y-axis potentiometer IOK. Torch height position signal 1
1 is compared with the reference value signal 13 outputted from the inversion reference value setter 12 by the comparator 14, and when the two values match, generates the /e pulse signal 15, and this signal generates the signal 9. A torch swing direction reversal signal 18 is sent to the X-axis motor controller 17. Upon receiving the reversal signal 18 , the X-axis motor controller 17 sends a command signal to the X-axis motor 19 to completely reverse the swing direction of the torch 3 , thereby changing the rotation direction of the X-axis motor 19 and rotating the torch 3 . By reversing the swinging direction and repeating this control within the groove, beads a and b shown in FIG. 2 are formed. 20 is X
The shaft block 21 is an X-axis movement speed setting device for rotating the X-axis motor 19 at a predetermined speed.

Next, the operation when forming beads c and d will be explained. The movement of the torch 3 in the width direction within the groove is as follows:
The X-axis potentiometer 22 outputs the torch X-axis direction position signal 23, and the memory circuit 24 receives the torch reversal signal 25 output from the X-axis motor controller 17, thereby inverting the direction of the torch 3. The X-axis position signal 26 at that time is stored in memory.

Next, this position signal 26 has a swing width 1. shown in FIG. 2 (b). ．． 12.13... Generates the swing width set value Xw corresponding to Torch reversal positions B+, B2, Bs... in figure (b)
A reversal position signal 30 indicating .

This signal 3 signal is compared with the torch X-axis direction position signal 23, which indicates the moving position of the torch 3 in the X-axis direction, which is sent every moment from the xm both/shome meter 22, by the comparator 31, and the two values are the same. At the same time, the signal 32 is sent to the d' pulse generator 16, which gives the oscillation direction reversal signal 18 to the X-axis motor controller 17. Step 19: Change the direction of rotation to reverse the direction of swing of the torch.

33 is a welding control switching circuit, and a switching contact 33a.

33b and 33c, and by operating the knob 34 to switch between the contacts 33a, 33b, and 33c, it is possible to select a welding control form that corresponds to a change in groove width. The above-mentioned contact 33a controls the reference 1 (bead amb18) in which the torch that swings within the groove is inverted between the left and right wall surfaces of the groove according to the conventional method, and the contact 33b swings inside the groove. For control when the moving torch is reversed on the right wall of the groove, swung to the left by a certain width t, and then reversed (bead C), contact 33c is used to control the torch that is oscillating within the groove on the left side of the groove. The welding control switching circuit 33 is a contact point that activates the control when the welding is reversed on the wall, swung to the right by a certain width t, and then reversed (bead d). The signal 35 for generating the torch swing reversal signal 18 according to the welding control form is transmitted to the - or Lus generator 1.
Send to 6.

That is, in the welding copper 1 cutting circuit 33, when the contact 33a is selected, the signal 35 for generating the torch swing reversal signal 18 with only the signal 15 from the comparator 14 is generated when the contact 33b is selected. The signal 35 generates the torch swing reversal signal 18 in which the torch is reversed at the right wall of the groove by the signal 15, and is reversed after swinging a certain width to the left of the groove by the signal 32. When the contact point 33c is selected, the torch is reversed at the left wall of the groove by the signal 15,
Then, a signal 32 is sent to either a signal 35 for generating a torch oscillation reversal signal 18, which causes the torch to oscillate to the right of the groove by a certain width and then invert, or to the Norse generator 16. - swing control is performed.

Note that the position signal 23 of the torch in the groove inner width direction outputted by the X-axis potentiometer 22 is also sent to the welding control switching circuit 33, so that the welding control switching circuit 33
A check is made that the signal 35 from the torch corresponds to the direction of the oscillating force of the torch.

The knob 34 in the welding control switching circuit 33 may be operated manually by an operator or automatically according to a predetermined sequence.

As mentioned above, this invention is based on j1! +Since it has been made,
During multi-layer welding, even when the groove width is wide and one weld layer is welded with multiple threads, the swing of the torch is
It can be reversed at a constant width, and an industrially excellent effect is brought about in that the torch can be accurately traced in the welding line direction in multilayer welding, which has been considered difficult in the past.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a bead in multilayer welding, Figure 2 (
b) (→(→ is an explanatory diagram showing the principle of this invention, and FIG. 3 is a circuit diagram showing an example of the control circuit of this invention. In the drawing, l, 1'...base material 2 ... Electrode 3 ... Torch 4 ... Welding voltage detector 5 ... Vehicle pressure reference value setter 6 ... Left dynamic amplifier 7 ... YSb motor controller 8 ... Y-axis block 9 ... Y-axis motor 10 ... Y-axis potentiometer 11 ... Torch height position signal 12 ... Reference value setter 13 ... Reference value signal 14
...Comparator 15...Pulse signal 16...
Pulse generator 17...X-axis motor controller 18...
・Torch swing reversal signal 19...X-axis motor 20...X-axis block 2
1... X-axis movement speed setter 22... X-axis potentiometer 23... Torch X-axis direction position signal 24... Memory circuit 25... Torch inversion signal 26... Position signal 27... Oscillation width setting device 2
8..., reference swing width signal 29... swing reversal position calculator

Claims (1)

[Claims] While moving the torch along the bath tangent line while maintaining a constant distance of 41 L between the torch and the groove, the torch was moved in the width direction of the groove (from this oscillation, the interior of the groove was multi-layered). Multi-layer welding welding method Based on the set oscillation width of the torch, a reversal position of the torch at the other 1 Hll within the groove is determined, and the torch is
When you reach the reverse position and make 1, that Q! 1/Ik
A multi-layer welding method in which the standby step is to reverse the rotation and perform bath contact while repeating such (+i) moving and rolling motions.