SU1458122A1 - Apparatus for controlling heat treatment of welded joints - Google Patents

Abstract

The invention relates to the field of welding equipment, namely to machines for butt contact welding of strips with subsequent heat treatment of the welded joint directly in the jaws of the welding machine, and can be used in heat treatment control systems in welding machines. Purpose of the Invention1 The invention relates to welding equipment, namely, butt welding machines for flash strip welding and subsequent heat treatment of the welded joint directly to the jaws of the welding machine, and can be used in heat treatment control systems in welding machines. FIG. 1 shows a diagram of the device; in fig. 2 is a schematic of a cooling rate shaper. The aim of the invention is to improve the quality of welded joints and reduce downtime during adjustment. nor - improving the quality of welded joints and reducing downtime during adjustment. The device includes a welding transformer, a thyristor interrupter, a pulse-phase control system, two switches, a current sensor, a square pulse shaper, a time counter, an amplifier with setters for the upper and lower output levels, a cooling rate driver, and a power source. In addition, an integrator, three multipliers, five operational amplifiers, three keys, a rectifier with a low-pass filter, a button for manually controlling the duration of current flow of the upper and lower levels were introduced. The device allows you to automatically set the required initial level of smooth cooling, which ensures a predetermined rate of decrease in the temperature of the welded joint, and in the process of heating by maintaining an equivalent current, isothermal holding. The invention provides reproducible modes and optimal heat treatment conditions for welded joints regardless of changes in external influences. 2 Il. Device for controlling heat treatment of welded joints / contains welding transformer 1, thyristor interrupt 2, system 3 of pulse-phase control, first switch 4 (electromagnetic relays are used as the first and all other switches), cooling speed generator 5, amplifier 6, setpoint 7 the upper current level, the setting unit 8 of the lower current level, the shaper 9 square pulses, the time counter 10, the second key 11, the current sensor 12, the rectifier 13 with a low-pass filter, the third key 14, the first multiplier 15, and square (L 4; i. cd 00 th

Description

torus 16, fourth key 17, first operational amplifier 18, second multiplier 19, fifth key 20, second operational amplifier 21, third multiplier 22, manual control button 23, third operational amplifier 24, fourth operational amplifier 25, fifth operational amplifier 26, potentiometer 27, start relay 28.

The welding transformer 1 (Fig. 1) is connected to the network through a thyristor breaker 2, the control inputs of which are connected to the outputs of the system 3 of the pulse-phase-shift control, the input of which is connected through the first switch 4 to the first output of the former 5 (Fig. 1.2 ) cooling rates and amplifier 6 (Fig. 1) with setters 7 and 8 of the upper and lower output current levels. The input of the amplifier 6 is connected to the output of the rectangular impulse generator 9, the input of which, as well as the time counter 10, is connected via a second switch 11 to a power source. The first timeout is a time counter 10 connected to the first input of the cooling speed former 5. The current sensor 12 is connected to the rectifier 13 with a low-pass filter and through the third key 14 is connected to the first and second inputs of the first multiplier 15. The output of the first multiplier 15 is connected to the first input of the integrator 16, the output of which is through the fourth key 17 connected to the input of the first operational amplifier 18. The output of the first operational amplifier 18 is connected to the first input of the second multiplier 19, the second input of the second multiplier 19 is connected via the fifth key 20 to the second output of the time counter 10. The output of the first operational amplifier 18 is also connected to the input of the second operational amplifier 21, the output of which is connected to the first and second inputs of the third multiplier 22 and the second input of the cooling speed generator 5, the second output of which is connected to the second inputs of the time counter and the integrator, the third multiplier output 22 is connected to the input of the second operational amplifier 21, the button 23 for manually controlling the duration of current flow of the upper and lower levels is connected to the setpoint 7 of the upper level of the amplifier 6. The third output the time counter 10 is connected to the key winding 14. i

Shaper 5 (Figs. 1, 2) of the cooling rate consists of an integrator performed on the third operational amplifier 24, a comparator performed on the fourth operational amplifier 25, and an adder performed on the fifth operational amplifier 26. The potentiometer 27 sets the speed cooling (reduction rate 1eqb) - A voltage proportional to Uxe of the current flowing during isothermal holding is used as the reference voltage of the comparator. Thus, when the output of the integrator performed on the third operational amplifier 24 reaches such a voltage level at the output of the comparator performed on the fourth operational amplifier 25, the sign changes, the counter 10 and the integrator 16 are reset. The input (Totalizer; performed on the fifth operational amplifier 26, initially cooling is supplied with a voltage proportional to kB, which is then reduced by supplying the integrator output voltage of the integrator with the opposite sign to the second input. The rate of voltage variation at the output of the adder is determined by the level voltage on the potentiometer 27. To start the integrator, use the relay contact 28.

The device for controlling the heat treatment of welded joints works as follows.

After welding by the second activation key 11 of the heat treatment (the relay coil is located in the sequence control circuit of the welding pattern), the shaper 9 of the square impulses and the time counter 10 are turned on. The rectangular pulse generator 9, through the amplifier 6 with setters 7 and 8, of the upper and lower output levels, sends the first current key 4 to the pulse-phase control system 3 with the upper and lower levels of the effective value, which are closed at position 1. and duration 5 each, while the thyristor interrupter 2 switches on the welding transformer 1 for heating the welded joint with two levels of current. Simultaneously with the second key 11, the third key 14 closes and the signal from the current sensor 12 and rectifier 13 is fed to the two inputs of the first multiplier 15 and the current (I) is squared. A signal proportional to the square of the current (1) is fed to the input of the integrator 16. The integration is carried out before the end of the isothermal holding time determined by the time counter 10 (in the counter, the third output is disconnected from the common point of the circuit) and the third key 14 is opened.

The operator of the welding machine, controlling the temperature of the joint visually or by pyrometer, periodically (in case of overheating) interrupts the high current with the button 23. During the whole time the button 23 is pressed, a low level current flows through the connection and the superheated joint is cooled to the specified isothermal holding temperature . The duration of the closure of the button 23 is determined by the cooling time of the joint to the desired isothermal holding temperature. The duration of the closure of the button 23 is determined by the cooling time of the joint to a predetermined temperature. This more accurately maintains the isothermal holding temperature and increases the reproducibility of the heating regimes during heat treatment. The total isothermal holding time (/ „) is determined by the setting of the time counter 10. At the end of the specified heating delay, the first switch 4 switches to position II by the signal from the time counter 10 (the relay coil of the switch 4 is an element of the control circuit of the welding machine), the fourth 17 and fifth 20 switches close (the windings are not shown) and the driver 5 starts cooling rate (the relay 28 opens in the feedback circuit of the operational amplifier 24). In this case, the signal is proportional to H

national, enters the delio

the divider made on the elements 18, 19, and the input of the divider receives a signal proportional to / „from the output of the counter

10 times. With the release of the second multiplier 19

,

and

signal proportional to l dt / tn

goes to the input of the square root extraction unit, performed on elements 22, 21, at the output of which a signal appears,

portioned mqu

This signal

The cooling current is fed to the shaper 5, and from it, through the first switch 4 and the system 3 of the pulse-phase control, the corresponding current of the initial stage of the slow cooling is established. This current gradually over time, determined by the time setting, decreases to zero, after which the welding transformer 1 is switched off by the thyristor interrupter 2 and the device for controlling the heat treatment of the welded joints is reset.

Claims (1)

Invention Formula A device for controlling heat treatment of welded joints, containing a welding transformer, a thyristor interrupter, a pulse-phase control system, two switches, a current sensor, a square pulse former, a time counter, an amplifier with setters for upper and lower output current levels, form g hg -,P jr about 35 40 45 the world of cooling speed and power source, while the first time counter input and the input of the rectangular pulse former are connected via a second key to the power source, the outlet of the rectangular pulse former is connected to the amplifier input with setters of the upper and lower output current levels, the amplifier’s output via the first key and the pulse-phase control system is connected to the thyristor chopper, which is connected to the mains through the primary winding of the welding transformer and the current sensor, the first output of the counter time is connected to the first input of the speed controller of the cooling circuit, the first output of which is connected to the pulse-phase control system via the first key, and the second output is connected to the second input of the time counter, characterized in that. that, in order to improve the quality of welded joints and reduce downtime during tuning, an integrator, three multipliers, five operational amplifiers, three keys, a rectifier with a low-pass filter, a button for manual control of the current duration of the upper and lower levels, and A low-pass filter coupler is connected to the current sensor output and via a third key to the first and second inputs of the first multiplier, the output of which is connected to the first input of the integrator, the second input of which is connected to the second output ohm the cooling rate driver, and the integrator output is connected via a fourth switch to the input of the first operational amplifier, the output of which is connected to the first input of the second multiplier, whose second input is connected to the second output of the time counter via the fifth switch, the output of the first operational amplifier an amplifier whose output is connected to the first and second inputs of the third multiplier and the second input of the cooling rate former, the output of the third multiplier is connected to the input of the second peratsionnogo amplifier manual control button duration of current flow of the upper and lower levels connected to the upper level of the current setting device, the third time the counter output is connected to the winding of the third switch, the second end of which is connected to a power source. , K Yu, 6