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Institut Elektrosvarki Imeni E.o. Patona Akademii Nauk Ukrainskoi Ssr

An Ussr Institut Elektrosvarki Imeni E.o. Patona

Vadim P Krivonos

Nikolai V Podola

Sergei I Kuchuk-Yatsenko

Boris L Grabchev

Valery G Krivenko

Viktor Senderovich Lifshits

Alexei I Gorishnyakov

Vladimir R Andrianov

Boris L Chev

Alecsandr V Didkovskiy

Rifkhat M Shakirov

Mikhail V Bogorskiy

Valeriy G Krivenko

Evgeny I Dovgodko

Alexandr M Kobylin

A method of flash-butt welding in which the travel speed (V,) of the machine mobile plate and the welding voltage (U,) are changed (by preset programs) and the travel speed is controlled through negative feedback by welding current, the voltage being changed discretely for each flashing fixed interval of t,duration as a function of the increment of the actual average speed of flashing details of shortening (V,) during the previous flashing interval, V,value being maintained at the present level, lower than V,. The invention envisages a change of the coefficient of enhancement of the negative feedback in a discrete manner for each preset flashing interval of t,duration as a function of V,increment during the previous flashing interval. The invention further provides for an increase in the value of U,and a decrease of the coefficient of negative feedback to the set value until the speed has reached the set value of speed V,at which upsetting is switched on, or after the set value of Q,has been reached, U,is increased and the coefficient of negative feedback is decreased to the set value, these values remaining constant until upsetting is switched on.

Method of flash-butt welding

The apparatus comprises a current transformer coupled to the welding tranrmer primary and connected with an analog transmitter of the welding current and with a digital transmitter of the duration of short-circuits in the welding circuit, having a memory element at the output. The apparatus further includes an analog voltage transmitter coupled to the welding transformer primary, digital transmitters of the slip of the workpieces being weld-joined with memory elements at the outputs, installed in the machine clamps, a digital transmitter of the offset of the rod of the servo-operated control valve with respect to its housing, having a memory element at the output, an analog transmitter of the displacement of the machine's movable column, an analog transmitter of the fusion rate, as well as a device for digital recording of welding process variables, electrically connected to a first output of the programming device and including a commutator of analog signals, an analog-to-digital converter, an interface, a microprocessor, and a digital printer, all coupled in series. According to the invention, the apparatus incorporates a set of flip-flops whose number equals that of the control commands, univibrators, and an OR-gate whose inputs are electrically coupled via the corresponding univibrators to outputs of the flip-flops and to a second output of the programming device and whose output is coupled to the triggering input of the interface, and two encoders. The recording device additionally comprises an OR-gate which accomplishes an electric coupling of the outputs of the analog-to-digital converter and encoders with the information input of the interface. The inputs of one encoder are coupled to the outputs of the digital transmitters, the inputs of the other encoder are coupled to a third output of the programming device, and the control inputs of both encoders and of the commutator of analog signals are coupled to the address bus of the interface.

Resistance flash butt welding process monitor

The primary winding of a welding transformer is provided with controlled rectifiers and the primary winding of a current transformer. The secondary winding of the current transformer is connected to a welding current pick-up. The phase angle of opening of the controlled rectifiers is varied through a phase shifter and a programmer. A pulse shaper is provided for shaping pulses synchronized with the voltage of a supply circuit and has an output connected to a phase delay unit. An OR circuit is provided having inputs connected to the output of the welding current pick-up and to one output of the programmer, and an output connected together with the output of the phase delay unit through AND logical circuits and an inverter to the inputs of a voltage switching flip-flop having outputs each being connected in pair with another output of the programmer through additional AND circuits to corresponding inputs of the phase shifter. The programmer incorportes a welding current pulsation frequency pick-up having an input connected to the secondary winding of the current transformer, a program halt unit, a welding time counter, a decoder, a 'weld-on' flip-flop, an output flip-flop unit, and logical circuits to provide interaction between the control signals within the programmer.

Welder for continuous resistance flash-butt welding

A machine for continuous flash butt welding comprises control devices for the control of beginning-of-upset operation and upset value, respectively, and such control devices are provided in one unit (a computer). Also provided are a control device for automatically controlling the flashing-off speed and a welding current meter connected to a welding transformer. A sensor connected to the meter detects short-circuit duration in the welding circuit in response to outputs of a welding control enabling signal generator actuated at the final stage of flashing and in the course of upsetting. The inputs of the latter are coupled to the computer and the output is connected to an upset value deviation control circuit. The latter receives inputs from a circuit which detects slippage of the parts in the clamping jaws during welding. The upset value deviation control circuit is further connected to a sensor means for detecting misalignment of a rod of the follow-up slide valve relative to its body.

Machine for continuous flash butt welding

The invention relates to a device for welding workpieces that have a large cross-sectional area, as well as for cases of high welding power requirements. The device in accordance with the invention comprises a mechanism for continuously displacing the workpieces being welded with a controlled drive, a mechanism for imparting to the workpieces additional reciprocating motion, a welding transformer, and a means for controlling the speed of the drive. The drive speed control means includes a welding-current pulse shaper coupled to the output of a current transformer, the latter being included in the primary circuit of the welding transformer and a welding-current pulse-length setter. The latter and the output of the pulse shaper are coupled to a comparator, the output whereof is coupled to the drive control circuit. In the course of flasing of the butt ends of the workpieces being welded, the welding-current pulse length is measured during each reciprocation period, and, depending on the error signal furnished by the comparator, the speed of continuous displacement of the workpieces being welded is adjusted.

Device for controlling the process of flash-butt welding

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Kyiv, Ukraine

Vadim P Krivonos