SU893463A1 - Automatic control method of the high-frequency welding process - Google Patents

Description

re welding, take the value of this part of the current. ,

Figure 1 shows a flowchart that implements the method.,. and FIG. 2 - long stand pipe welding, bc; {bypassing a part of the welding current. The block diagram contains the meter 1 TO.GSH1INY of the tape being welded, the sensor 2 of the welding current, I turn on the stand with a split shaft, elements 3 and 4 of the comparison, the summing element 5, the thickness setting unit 6, the setting unit 7 of the welding current, amplifier 1; mismatch body 8, regulator 9, body 10 of the manual control of the power of the high-frequency generator, indicators 11 and 12 zero high-frequency generator 13, a moldable belt 14.

The shunting parts of the current are carried out using a special with a split roll stand for welding pipes.

The cage consists of the lower roll 15, the left 16 and the right 17 halves of the upper roll, mounted on the frame 18 On the frame 18 spring loaded current collectors 19 and 20 are also installed. The axis of the rolls 21 is electrically isolated from both the frame 18 and the roll halves 16 and 17.

Pipe billet 22 enters the caliber formed by the rollers, touching with its edges the halves of the upper roll. Part of the current induced in the edges of the workpiece by the inductor, is supplied from the left edge of the workpiece 22 through the left half 16 of the upper roll j through the current collector 19 and, respectively, from the right edge of the workpiece 22 through the half 17 of the upper roll and the current collector 20 ne rectifier input, from the output rectifier - on the amplifier. A cage with split rollers, straightener and booster are two welding size sensors. current.

The operation of the mill is provided in the manual control mode and in the automatic control mode. In the manual control mode, the connection between the reference element 4 and the controller 9 is broken.

Before switching on the mill to the automatic control mode, a manual adjustment was made, changing the power of the generator 13 using the manual control unit 10. At the same time, the lowest value of bur is achieved with satisfactory welding quality. Selecting the desired welding mode, set the dials 6 and 7 in. So that the indicators 11 and 12 zero show zero. After that, the mill is placed in automatic control mode.

The device in automatic control mode works as follows.

If the disturbance factor, for example, a change in the width of the formable tape 4 or a change in the voltage of the mains network, decreases as a result of a disturbing factor, then the signal from the welding current magnitude 2 to the input of the reference element 4 also decreases; will decrease. On v: during element 4, the comparison with the Wits signal,

under the influence of which the regulator 9 increases the power at the output of the generator 13 until the signal from the sensor 2 of the welding current reaches its previous value. At the same time welding current

compared to the preset and the temperature of heating the edges does not decrease.

When the thickness of the welded tape is changed at the output of the comparison element 3, a signal is produced that is proportional to the change in the thickness of the moldable tape, acting on the input of the error amplifier 8. Under the influence of the signal from the output of the amplifier 8

the mismatch decreases the signal of the output of the summing element 5, which is equivalent to a change in the signal from the sensor 7 of the magnitude of the welding current. Thus, the input signal of the reference element 4, which was equal to

the signal from the setting device 7, corresponding to a certain thickness of the tape,

depending on the increment of the thickness of the tape passing through the zone.

rvarki Since the thickness of the tape has decreased, the signal of the summing element 5 is reduced by the comparison element 4. At the same time, the signal at the input of the regulator 9 is shown; the generator power will decrease until

until the signal from the output of summing element 5 is comparable with the signal of welding current sensor 2, which also decreases with decreasing generator power. In this case, the welding current will decrease, and the welding temperature will not increase due to the decrease in the tape tip, but will remain within the specified limits.

 The magnitude of the transfer coefficient of the amplifier 8 misalignment selects, with empirically.

The proposed method allows the stabilization of the welding temperature, without resorting to the use of photo sensors and pyrometric sensors, which leads to an increase in the reliability of stabilization. In addition, the adjustments of the signal are obtained immediately at the time of welding, which means that the system speed and the quality of the adjustment can be increased.

In addition, bypassing a part of the current that runs along the edges immediately before the point of cooling the edges,

65 improves the form of internal debts.

Claims (1)

Claim A method for automatically controlling the process of high-frequency welding of the longitudinal edges of a molded tube billet, in which the power of the heating source is changed depending on deviations of the thickness of the moldable tape and the value characterizing heating in the weld zone, characterized in that, in order to increase the reliability and quality of stabilization Welding ness, immediately before the convergence point of the workpiece, a part of the welding current is shunted and the value of this j part of the current is taken as a value characterizing the heating in the weld zone.