JPS597476A - Method for controlling arc welding with consumable wire electrode - Google Patents

Abstract

PURPOSE:To perform arc welding with a cunsumable wire electrode and with excellent restartability of an arc, by restarting the arc without controlling the starting of a wire feed speed or supply voltage when a quiescent time is shorter than a specified time. CONSTITUTION:A secondary voltage is controlled with a main voltage regulator 7 in accordance with the stopping inertia of a wire 2 in the stage of ending welding by the control of a timer T3 with a switch 18 and selector switches 15, 16, whereby the shape at the forward end of the wire 2 is controlled to a satisfactory state in an arc welding device with a consumable wire electrode which feeds the wire 2 to a base metal 1 with rolls 4 driven by a motor 9 and supplies the welding voltage with a main transformer 5 and a main thyristor 6. Selector switches 10, 11 and a switch 12 are controlled with timers T1, T2 to control starting of a wire feed speed and the secondary voltage at the values differing from the value in a steady time with a wire speed regulator 8 and the regulator 7 when the quiescent time is long, and to restart the arc without controlling the starting when the quiescent time is short.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling consumable wire electrode arc welding.

Conventionally, in order to improve arc restartability (arc start), control has been carried out using a method as shown in FIG.

That is, at the end of welding, the inertia t of wire feeding. By applying a voltage v3 and a voltage tt3 for a certain period of time in consideration of the above, the shape of the tip of the wire 2 (FIG. 3) was controlled to be a hollow rectangular shape as shown in FIG. When the melting of the wire 2 becomes appropriate and a soil part 2a is formed at the tip of the wire 2 as shown in Fig. 2, the contact resistance and area of the wire 2 end at the start are large, so that a soil part 2a is formed at the tip of the wire 2 as shown in Fig. 4. In addition, there are many cases in which a smooth start cannot be performed, and the second end of the wire flies off, leading to an arc. In addition, 1 is a base material, 3 is a torch, and 4 is a lobe. 9, star 1
Sometimes, the feeding speed of wire 2 is slowed down by 12 as shown in Figure 1 to facilitate melting of the wire tip and smooth arc transfer, or to increase the power source power by the amount of secondary voltage v2. The idea was to increase the energy when the wire 2 comes into contact with the base metal 1, thereby improving arc start. Note that each of these controls operates constantly once they are set. Therefore, no matter how the time until the start of welding changes, such as 'IEI e' LL, the operation will be repeated in the control form shown in Figure 1. However, when the pause time is relatively long, the tip of the wire 2 It's too cold for a second time
The control shown in the figure is effective, but when the pause time is short (for example, 1
．． 1 second to finish welding 20OA with 2φ hot wire
(within 2 seconds), the tip of the wire 2 is still in a red-hot state, and the energy applied to the wire 2 end is too large, which may actually cause the tip to scatter. There are many welding operations with such short downtimes.

Therefore, it is an object of the present invention to provide a control method for consumable wire electrode arc welding that exhibits excellent arc restartability regardless of whether the downtime is long or short.

An embodiment of this invention is shown in Fig. 5 and Fig. 6. That is, this control method attempts to classify the start control according to the work stoppage time, and as shown in FIG. 6, when the work stoppage time t・1 is short like 'Is, various controls are stopped, The control is activated only when the pause time is long, such as in the case of t. Of course, not only the control is turned on and off, but also the value of the control itself (for example, t in Figure 6).
, or v2) depending on the pause time.

FIG. 5 shows an example of a device implementing this control method.

2 is a wire, which is fed to the base material 1 by a row Wy4 driven by a motor 9. 5 is the main transformer, 6 is the main thyristor, 7 is the main voltage regulator, 8 is the wire speed regulator, 10, 11115° 16 is the changeover switch, 12.1
8 is a switch, and T-T3 are timers.

The changeover of the changeover switches 15 and 16 controls the output at the end of welding as shown in v3 in FIG. 6, and sets t in FIG. 6 with the timer T3. This eliminates the formation of a dirt portion 2a at the tip of the wire 2 as shown in FIG. 2, and ends the arc with a sharp wire end as shown in FIG. The changeover switch 10.11 controls f2 # V2 in FIG. 6, and its time t2 is set by a timer T2. This also prevents the start as shown in FIG. 4 and ensures smooth arc transition when the two ends of the wire contact the base material 1.

The timer T performs control that is different from the conventional one in this invention, and the function of the timer T2 described above (changeover switch 10.
11) is controlled over a certain period of time. That is, as shown in FIG. 6, the timer is set so that when the pause time is short, the timer is set so that the pause time is short, and when the pause time is long, the timer is set as A. Note that Δt in FIG. 6 indicates the starting inertia of the wire. If the pause time is short, the tip of the wire 2 is also in a red-hot state, and the arc can be sufficiently started by controlling the arc as shown in FIG. In the control shown in A in Fig. 6, the energy applied to the wire 2 end is too large and the tip may scatter, but by controlling the wire 2 in this manner, it is possible to prevent the wire 2 tip from scattering. A good arc start can be performed.

In this way, good restartability can be obtained even when the downtime is short, so the present invention is suitable for welding work that involves many short welds.

Note that the same effect can be obtained even if the constant of t2°v2 of A is changed to a value between A and A in FIG. 6. Furthermore, although the above embodiment has been described for the case where both the wire feed and the supply voltage are start-controlled at the same time, the present invention is also applicable to the case where only one of them is start-controlled or when both are controlled with a time difference. can do.

Further, the present invention can be applied to CO2 welding, MAG welding, and other consumable wire electrode arc welding in general. In this case, this method does not perform start control of the wire feed speed or supply voltage, or controls the start to a different value than when the time is longer than the above-mentioned fixed time, so it is an excellent restart regardless of the work stoppage time. It has the effect of giving you sex.

[Brief Description of the Drawings] 1N is an explanatory diagram of the operation of the conventional control method, FIG. 2 is a side view showing a defective state of the wire tip, FIG. 3 is a side view showing its good state, and FIG. 4 5 is a side view of the vicinity of the torch showing a defective state at the start of welding, FIG. 5 is an explanatory diagram of the configuration of an example of a device for carrying out the method of the present invention, and FIG. 6 is an explanatory diagram of the control operation of an embodiment of the present invention. be. 1... Base material, 2... Wire, 5... Main transformer,
6... Main thyristor, 7... Main voltage regulator, 8...
・Wire speed regulator, 9...Motor, 10.11
．． 15゜16...Selector switch, 12.18...Switch, T□~T3...Timer

Claims (1)

[Claims] A control method for consumable wire electrode arc welding in automatic or semi-automatic welding, in which the wire feed speed, the supply voltage, or both the wire feed speed and the supply voltage are started at a value different from that during steady state when the arc is restarted. , if the time from arc stop to restart is less than a certain time,
Consumable wire electrode arc welding characterized in that the start control of the wire feeding speed and supply voltage is not performed, or the start control is performed to different values from the start control so as to prevent overheating of the front six wires. control method.