DE2713329A1 - Flash butt welding steel strip - used for mass prodn. of continuous strip for cold rolling - Google Patents

Abstract

Weldin plant, using a power supply for joining workpieces in a number of steps, includes a meter which monitors the power used in one step. The monitor is linked to a controller for adjusting the power used in another step. The plant is pref. a flash butt welder, where the power used in the flash controls the force used in upsetting, esp. via a direct ratio. Appts. pref. includes electrical- and mechanical- power supplies; electronic and hydraulic circuits; and a recorder showing the integrated electric power w.r.t. time. The electronic appts. pref. uses logic, memory and comparator circuits so the amt. of electric power in the flash directly controls upsetting force in a completely automatic cycle. Used to join the tail end of one steel strip to the front end of the next strip to obtain continuous strip for cold rolling and heat treatment. The invention ensures that completely reliable welds are obtd. in large scale mass prodn.

Description

Device and method for flash butt welding

The invention relates to a device and a method for flash butt welding and more particularly to an apparatus and method for repeatedly performing good and uniform flash butt welds between sections of strip material.

Strip steel products are typically made from steel slabs, which are referred to as billets or blanks. A board is heated up and hot-rolled, so that relatively thick steel strips are produced, which are then further processed will.

For the production of strips that are processed after the hot rolling process relatively long steel belts are required.

The strips produced in the hot rolling process are typically welded together with their ends, so that tapes of sufficient length result, to carry out the fairly continuous and efficient operations, for example pickling and cold rolling.

The welds that join hot rolled strips together should ideally indistinguishable from the tape material itself so that the welded piece can form part of a final product made of strip steel.

In addition, more importantly, the weld seams must be sufficient be flexible and durable so that they allow the subsequent strip rolling operations, without the weld seams being destroyed or opening.

For example, a weld seam breaks during a cold rolling process serious problems. The production is interrupted and this results in a large cost caused. In addition, destroyed weld seams can cause serious damage to the Production facilities, for example arranged on the roller mills for cold rolling will.

When strips are welded, they are produced by hot rolling Ribbons sent through a trimmer, the irregular material from sever the ends of each ribbon. The amount of cut material is sufficient to produce uniform ribbon ends.

A flash butt welder is then used to weld adjacent Join the ends of a total of four to five reels of tape and make a longer tape to manufacture. The longer tapes made by welding different Ribbons formed are to be processed at a higher speed than when the individual bands separated would be further processed. The setup time for the various processes is reduced when dealing with crazier tape reels, because fewer set-ups are required to process a certain amount of steel, when larger spools or longer tapes can be processed.

A welding process is often used to join the ends of adjacent ribbons used, which is known as ibbrenn butt welding. When welding two strip ends after the flash-butt welding process are the other adjacent, ends of the bands to be welded together to one of two conductive and clamped against each other movable plates. The end sections are on top of each other too moved and subjected to the burning and upsetting processes, while electrical Current passes between the} tape ends, so that the metal is heated and the weld is effected.

In the burn-off step, the adjacent tape ends are over a a predetermined distance of about 10 to 20 mm thereby moved towards each other that the plates are moved against each other by a hydraulic movement system. An electrical voltage is applied to the ends through the conductive plates. When the ends have moved close enough to each other, this will Voltage causing an arc between the two pieces. When a touch takes place, there are a number of many local shorts between the neighboring edges and thus a high current density in these short circuits. These local high current densities heat up areas where the electrical Short circuits occur. This series of local shorts or "bridges" is spreading extending over the entire length of the weld seam, while the plates and thus the adjacent ends are progressively moved towards one another, until the entire area near the adjacent ends has a sufficiently high temperature achieves that the material melts. This burning step requires some Welding machines 1-2 seconds, with others 8-20 seconds.

After the burn-off step, the weld is completed in that the melted ends under great pressure of the hydraulic system in the upsetting step are pressed together while continuing to maintain an electrical voltage will. In the previously common methods, the electrical current is between the Tape ends during upsetting essentially during a fixed, predetermined Maintain the time span and then interrupt the power supply to the weld seam. The upsetting force unites the molten metal at the adjacent ends and also removes the unwanted slag or scale that is present. The electrical current must be maintained long enough during upsetting that the union temperature for the metal remains until the Welding has been carried out, but this process should not take as long as that more molten metal than necessary melts from the weld area.

After the weld has been completed by upsetting, it becomes superfluous Material removed, ideally a relatively smooth and uniform joint area remains between the ligaments. The weld should have a homogeneous composition which corresponds to that of the previous material of the steel strip product.

The welding process should use the material adjacent to the weld not weaken.

The common devices for providing the electrical The heating current for the welding contains a voltage source of 440 volts alternating current, a Transformer for generating a low voltage with many Attacks and a circuit that allows a phased and low voltage Power flow can be controlled and transmitted from the voltage source to the plates can. The low-voltage power becomes the conductive plates and thus too transferred to the clamped ends of the tape. When a weld is to be carried out, will the circuit switched to transmit electrical power and the hydraulic system is switched on so that it is the plates and thus the ends of the tape clamped to them moved towards each other to carry out the burning process.

Devices are provided that detect the point in time when the tape ends have approached each other within a predetermined distance ('tStuppeuchlage ") and then initiate the upsetting. During the upsetting the ends are moved towards each other in a very short time and the current flow remains is maintained for a predetermined time and is then interrupted. the Edges can then cool down during a predetermined "hold time" before the Plates are clamped from the joined tape ends and these are trimmed.

The amount of electrical energy used during the welding process Energy has a significant effect on the quality of the weld made. The previously known measures for controlling the energy have focused on adjust the energy applied during burning. There were fixtures created to regulate the energy so applied. These devices included Devices for adjusting the parameters of electrical power transmission, for example the transformer taps. Mechanical adjustments were also made taken to regulate the burning energy, for example the speed was of the plate movement and the limits of the displacement path of the plates became fixed.

The time during which electrical current continues during upsetting flows, on the other hand, for a given thickness range of material and determined by tests for different types of material and essentially constant kept because the energy controls for the entire welding process only through the Controls were carried out that were effective during the burn-off process. Normally the time of the current flow during the upsetting process was evenly reduced to one set maximum value in order to avoid excessive heating during upsetting, what else a melting of material from the weld and thus a weakening the weld would have resulted.

The circuit consists of two so-called "Ignitrons" (single anode gas discharge tubes with ignition electrodes), which are switched in a known manner as a phase control switch are. The means for adjusting the power delivered by the circuit enclose two potentiometers, one of which is used to set the burning power and another one with which the upsetting power is set.

The potentiometers are connected in a known manner so that thereby the phase position of the ignitrons is controlled, i.e. the time during each current period is set, during which the Ignitrons electrical power on the? rimärseite of the source transformer.

Despite these elaborate efforts to keep up with the manufacture Controlling the electrical energy expended by weld seams fails far too well many welds under the stresses of further processing. The discussed Setting options for the parameters are made imprecisely and apparently often ineffective. The adjustment requires considerable experience and practice on the part of the operator.

The desired, energy-related attitudes lead to a Number of variables in the setup process for making welds. Since most of the operators do not have sufficient experience to handle the individual To be able to make settings for each welding process is in the form of setting panels helped. The setting panels are constructed in such a way that for the sheet metal dimensions (sheet thicknesses) and values are given for the material to be welded. The operator can look up the respective size and type of material on the card and find one Number of corresponding recommended setting values that relate to energy and others Sizes are related to the particular material of the particular type and strength should apply.

Despite these attempts, the selection of the many setting variables too simplify, errors occur and it is not possible to make welds of good quality Constantly producing quality.

With the setting cards, value ranges are necessary for certain Setting values specified instead of a single fixed setting value for each value and each material is specified. The cards turn out to be inaccurate Choosing variables of what is obviously the problem in making good ones Weld seams enlarged.

The destroyed weld seams (so-called "band breaks") result in economical Losses including downtime, machine damage and interruptions in the Work schedules.

Belt breaks occur in the roller mills in which the measure or the strength of the strip material as it passes through opposing ones Rows of heavy rollers is reached, taking very high pressures below tension be applied. When such tape breaks occur, the tape material folds one on top of the other within the roller frame, which means that the strip material is twice or three times thick pass between the rollers. This causes the roller mills to clog, they are stalled and the rollers get grooves or even cracks.

The downtime caused by a belt break often lasts several times Hours. A scratched roller must be re-sanded to keep its surface and their shape is restored. The regrinding will of course be shortened the life of the roller decreases as some of its material has to be removed. if a roller is so badly damaged that it has to be replaced, there is a cost of several 10,000 DM.

Therefore, it is a primary object of the invention to provide an apparatus and a To create a process with flash butt welding between individual workpieces can be produced with improved quality and uniformity.

The invention relates to a method and an apparatus for implementation improved flash butt welding for joining consecutive ones Groups of adjacent workpiece edges of strips, whereby the properties of the workpieces, for example the thickness and the material, different from a group of workpieces to the other can distinguish.

The invention provides an improved welding device, through which energy is transferred to workpieces to make a weld in a variety of single steps. The welding machine has a monitoring device, to record the energy used in one step and a control circuit, the energy applied in a further step as a function of the recorded Control amount of energy.

Another feature of the invention is that the welding machine is a flash butt welder and that the energy applied during upsetting is a function of the amount of energy used in the burn-off process.

It is believed that an explanation for the improved performance of the welding device according to the invention can be found in that, in contrast to the previous considerations the various settings discussed at the beginning No or only little regulation of electrical energy during burning Have an effect on the actual amount of energy applied. Generally speaking are the only parameters that significantly influence the combustion energy Type of material to be welded and the amount of material that melts during the burn-off Material, i.e. the product of the cross-sectional area of the weld seam times that of the Plates covered distance during burning. (This of course applies only as long as the speed of movement of the workpiece ends during the Burning process is not greater than the speed with which the expended Power can melt the metal.) With a material of a certain type and Dimension and with a constant distance covered (burning length, this distance is generally kept constant in practical use) is that for burning off required amount of energy essentially constant. It has been shown that at constant held burning length the cross-section of the workpiece the amount of during the Burning off the burned-off energy used. Tests have shown that when changing any dimension of the cross-section, the burn-off energy increases changed substantially proportionally with the change in cross-sectional area.

Therefore, in flash butt welding, the amount of flash energy can be determined does not affect when the burn length and the cross section stay constant. The energy used in welding can be influenced can essentially only be achieved in that the during the upsetting process delivered energy is controlled. So far, the energy given off during upsetting is kept essentially constant because it is mistakenly believed that the settings just discussed have an effective effect on the total energy during welding could by regulating the combustion energy accordingly.

By focusing essentially on the change in only one variable, i.e. the duration of the current flow during upsetting, leaves to the energy will control the need for many of the energy related setup settings listed eliminated and the adjustment process during welding for the operator essential simplified. This improvement results in faster set-up and enables more uniform welds in that one no longer has to rely on the assessment must leave by the operator.

Another special feature of the invention is that the control circuit limits the compression energy to an adjustable amount that is directly is proportional to the burn-off energy, resulting in an adjustment of the total energy allows the welding process.

According to another aspect of the invention there is provided a method and provided an apparatus wherein a flash butt welder includes an energy monitor for detecting the electrical energy generated during the burning and the Upsetting is passed on to the workpiece, and in which an energy recording device, responsive to the monitoring device, an indication of the by the monitoring device detected energy generated.

The energy display device provides a permanent record of the in each Section of each weld expended energy for later evaluation, which means a correlation between the amount of energy used and the quality of the weld is made possible.

According to another aspect of the invention, the total welding energy determined by measuring the energy given off during burning, that a signal is generated and stored that the combustion energy and thus the represents effective cross-sectional area of the workpieces and that the during the Upsetting consumed energy is controlled depending on the burning energy.

The invention is illustrated below with reference to the drawing, for example explained in more detail; In the drawing: Fig. 1 shows a block diagram of a strip rolling process with the use of the invention, FIG. 2 shows an illustration of a device of the type shown in FIG. 1 using the invention, FIG. 3 is a block diagram of a Section of the device shown in Fig. 2, Fig. 4 is a schematic diagram of the In Fig. 3 in block form shown device section, Fig. 5 is a schematic Diagram of another embodiment of the device section shown in block form in FIG.

In Fig. 1, the devices of a production line are in block form L using the present invention. The manufacturing line L produces steel strip material from steel slabs S by placing these slabs in a Number / consecutive steps processed will. In the The production line shown in Fig. 1 is for the production of approximately 50,000 tons Steel strip material suitable per month.

The steel slabs S, which are the starting material, are approximate 6.1 m long, 1.2 m wide and 15.24 cm thick (= 20 ft x 4 ft x 6?). The slabs will first heated to a temperature of approximately 120400 (= 22000F) and through a hot rolling device 10 is left to reduce the strength. The hot rolling device 10 has a number of opposing rollers, the steel slabs S can be passed through the gap between the rollers in order to increase the strength of decrease approximately 6 inches to approximately 1/4 inch to 1.27 mm. (= 0.25 to 0.050) each band-shaped board (shown at 12 in FIG. 1) is heated to a temperature of about 700 to 76000 (= 1300-14000F) and then cooled through a winder 14 processed into a spiral wrap so that it is easier to handle. Each roll has a width of 559 to 1270 mm (= 22 to 50 ") and the weight is between 4,500 and 9,000 kg (= 10,000 to 20,000 lb).

The wraps of tape material are stretched flat again, trimmed and welded together by a flash butt welder 20, namely each about five tapes are made into a long tape to create a continuous one To enable processing of larger quantities of strip material than would be possible through further processing the individual winding would be possible. A cutting device 22 takes place before the welding process Pieces more than 25mm wide from each end of the wrap to rough and irregularly shaped ends to be eliminated and regular end pieces made of homogeneous, to expose good tape material for the welding process.

After trimming the adjacent ends are from one behind the other four or five coils joined together in sequence in the flash butt welding system 20, using the present invention.

After the strip emerges from the hot strip mill and becomes a lap often has an undesirable top layer of iron oxide on its surface found which has a thickness of about 12 to 25 µm (= 0.0005 to 0.001 "). This material, known as "slag" or scale, must be removed in order for it to be removed the product can be easily processed and no impurities are introduced will.

This scale is removed by a pickling device 24 in which The tape is exposed to hydrochloric acid, which chemically interacts with the slag or the scale reacts and removes these substances.

The joined strips are then further cold-rolled. at the strip material is sent to the cold rolling process through a "tandem rolling mill" 26, where there is between opposing pairs of rollers under high pressure and high Tension is brought through, the thickness of the tape material except for one Value of 0.38 mm is reduced. This processing takes place at ambient temperature instead of.

After this cold rolling, the strips are welded together again brought into the form of large rolls in a winding device 28 and in one Tempering furnace 30 tempered so that the material for the subsequent processing stages becomes more malleable. A coolant overflows during the cold rolling process the surfaces of the tape material, which consists of approximately 6 ió vegetable oil in water. The tempering process is carried out while the strip material is being wound is, and within certain limits it takes no longer to start a large wrap than that of a small one, with which the starting process is considerably faster if the tape material is wound in large quantities.

After being left wet, the strip material is then passed through a tempering mill 32 so that the properties of its hardness profile are improved.

It is necessary that the welds between the adjacent smaller sections of the strip material as good, uniform and homogeneous compared to the mother material are, as only possible, thus a possible break-up during the further processing steps is avoided.

In processing such as cold rolling, the strip material is under high tensions are set, with speeds of 610 to 915 m / min moved, causing the between the adjacent sections of tape material previously produced welds are heavily stressed.

As explained above, it can have significant economic and other disadvantages arise when a weld seam is joined during the subsequent processing of the The band material breaks.

Figure 2 is a pictorial representation of the flash butt welder 20 embodying the present invention. The welding device 20 welds butt adjacent ends of steel strip material sections together to form long continuous ones To form material strips with a weight of 18,000 to 22,700 kg each. (= 40,000 to 50,000 lb). The material to be welded has a thickness of 1.27 to 6.35 mm (= 0.050 to 0.25 ") and a width of approximately 600 to 1270 mm (22 to 50 ").

Preferably used as a welding device in which the present Invention is applied, a "52-inch Flash Welder" from Taylor-Winfield Company, arten, Ohio, No. 55704. The components of this description The welding equipment discussed are the components, unless otherwise noted the welding device just mentioned.

Two adjacent ends of steel belts 40 and 40a are inserted into the welder 20 introduced after they have been trimmed so that they have uniform ends with good Quality are present. A; this ends is attached to a stationary conductive pressure plate 3Zk, while the other is clipped to a movable conductive pressure plate 36 is clipped.

A spacer bar (not shown) is placed between the two ends brought and the movable plate 36 moves with the one clipped to it End towards the other plate until both ends touch the spacer rod, whereupon this is removed.

The welding device performs a flash butt weld of each other adjacent ends through, first a burning process and then a upsetting process is carried out. During the burning process, the movable plate 36 is through actuates a hydraulic system 42 (FIG. 3) which is connected to a hydraulic piston 43 is to move the movable pressure plate 36 against the stationary pressure plate 34, so that the adjacent ends of the steel band pieces are moved towards each other. Simultaneously an electrical voltage is applied to the adjacent tape ends 40 and 40a, to heat the end areas and the material to enable a connection to melt.

The arc that carries the electric current between the ends the Ribbons become larger and larger, while the ends expand as a result of movement the pressure bar 36 to move further and further towards each other.

When the pressure plate 36 the workpiece ends to a predetermined Has moved the remaining distance towards each other, the upsetting process occurs when the pressure plate 36 presses the workpiece ends against each other with great pressure, while the electrical Power continues to be applied to the conductive pressure plates and the workpiece ends. The hydraulic system generates a signal when the workpiece ends up have moved the predetermined distance from each other, whereby the end of the burning process and the start of the upsetting process is displayed.

According to the invention is the duration of this continued flow of power a function of the total electrical energy generated during the previous burning process was applied to the workpiece ends.

The electrical system of the welder 20 that controls the application controlling the electrical power to the workpiece ends is shown in block form in Fig. 3 shown. The electrical system includes an AC power source 44 and an ignition switch 46, which transfers the electrical power to a primary circuit 48 of a power transformer 50 controls when an ignition control circuit 51 operates will. The power transformer 50 supplies the electrical power to the conductive ones Pressure plates 34 and 36 and the workpiece ends 40 and 40a, which are attached to the pressure plates are clinged to. The transformer reduces the voltage.

An energy monitoring device 52 is associated with the transformer 50 connected to the on the pressure plates and the workpiece ends during the burning process transferred to record electrical energy according to the amount.

According to the invention, a control circuit 54 is provided which responds to a start signal back sets the ignition control circuit 51 in motion to thereby the burning process by applying to introduce electrical energy to the workpiece ends 40 and 40a. The control circuit 54 is also responsive to the burn energy value obtained from the energy monitor 52 was detected and on the display of the hydraulic system 42 that the burning process is completed, and continues the operation of the ignition controller 51 to start the circuit 46 continues to deliver power to the transformer 50 (and thus to the workpiece ends), and thus this process continued for a period of time during the upsetting process becomes, the length of this period of time being a function of the total amount of electrical Is the energy that the workpiece ends received during the burning process.

An energy recorder 56 is associated with the energy monitor 52 connected and gives a graphic representation of the fed to the workpiece ends electrical energy during each welding process, against time applied. The effective cross-sectional area can also be determined from this recorded energy derive the weld seam and determine whether it fulfills the function described above is.

The AC power source 44 is a known device that uses single phase AC power of 440 volts and can process around 3000 kW of power. This performance is connected to circuit 46 in a known manner via a two-pole switch 60 forwarded. The circuit 46 includes a pair of so-called "Ignitron" tubes and is an accessory for the welding machine from Taylor-Winfield mentioned above. The transmission of the power through the circuit 46 can be regulated, switched on and off are made by the Ignitron Ignition control 51, which the phase position the Ignitron ignition changed.

The transformer 50 contains the primary circuit 48, the secondary circuit 61 and a device for secondary current correction 73.

The primary circuit 48 of the transformer 50 is used as a standard part of the Above mentioned welding machine from Taylor-Winfield is supplied and contains a coil assembly 66 and a device for changing the tap 70. The Tap changing apparatus 70 consists of a plurality of end clamps, which at 72 are indicated and which tap the coil 66 at different points. if the connection of the primary circuit at the various terminals 72 is changed, the voltage conversion ratio of the transformer 50 is changed. This adjustment option The voltage output of the transformer 50 can be between approximately 6 and 16 volts output voltage the secondary coil 61 change. The bhandle setting is very useful for the Current and heat load on the transformer 50 within the optimal limits without changing the electrical resistance between the ends of the steel belts to react, made up of different thicknesses of the belt material result.

A secondary current correction circuit 73 of known type is connected to the primary side of the transformer and, if necessary, connected to the energy monitoring device 52, to derive a signal from the primary side that is the actual signal on the secondary side flowing stream. This signal is sent to the energy monitoring device supplied so that it can derive the output signal, which is the total energy indicates that was released during the welding process.

The secondary current correction circuit 73 is a known resistor network for current transformers with taps, through which a current correction can be effected can.

The ignition control circuit 51 is also a standard component that comes with the welding device is supplied by Taylor-Winfield and that on the signal of the control circuit 54 reacts so that a pulse at a predetermined Point in time during. every half duty cycle of each Ignitron tube is released, whereby the point in time can change in its phase position.

In response to these impulses, the Ignitron circuit begins conducting power from the echselstromuelle to the primary circuit of the transformer and sets this line for the rest of each. Half cycle continued, being at the zero crossing of the current no current is passed until re-ignition by the next pulse. So will by specifying the point in time (expressed in phase angle degrees) at which the Pulses are sent out during the respective alternating current painting cycle, the fraction of the half cycle during which the Ignitron switch is conducting or powering transmitted to the transformer, and therefore this procedure can reduce the amount the power transmitted in this way can be changed.

The ignition control circuit 51 also includes a (further below in detail discussed) potentiometer circuit known structure, which in series with another (not shown) circuit of the ignition control circuit 51 is switched to the total resistance set this circuit. Adjusting this resistance controls in as is known, the phase angle of the alternating current half cycle at which the ignition control circuit 51 sends the impulses to the ignitrons, whereby the ignitrons are actuated to direct the remainder of the period of the associated half cycle.

The energy monitoring device 52 so connected to the transformer 50 is that it detects the electrical energy used during the welding process is a combination of a monitor model No. 901, part No. M228, a Model No. 903 relay circuit, part No. M227, and a connector Model 902, part no.

M226, from the Wean-United Company of Youngstown, Ohio.

The energy monitoring device 52 generates a voltage output signal, which is a function of the instantaneous total energy applied to the workpiece ends is transmitted during the welding process.

The control circuit 54 includes an output logic circuit 80 which is a Output from an adding amplifier 82 receives. The adding amplifier 82 generates a signal to cut off the power being transmitted to the transformer 50 when a fixed time has elapsed after the start of the upsetting process, whereby this time is a function of the amount of electrical energy applied to the adjacent strip ends was transferred during the burning process. A storage circuit 84 receives an output signal from the energy monitoring device 52 via an input logic circuit 86 and stores a signal with a value that represents the amount emitted during burning represents electrical energy and thus the effective cross-sectional area of the workpieces. After the occurrence of the signal from the hydraulic system 42 that the end of the burn-off process and indicates the start of the upsetting process, the input logic actuates the memory circuit 84 and the addition amplifier 82, so that the energy transfer to the neighboring Tape ends will continue for a time which is a function of the memory circuit 84 stored signal value. A percent control circuit 90 between the Input logic 86 and the addition amplifier 82 is connected, can be set be that he has the functional relationship between the length of power output during the upsetting and the burning energy in the previous burning step. This function is preferably a direct proportionality.

Preferably this embodiment of the invention includes a known one Compression time control 83, which optionally instead of the control circuit 54 for limiting the length of time the upsetting portion of the welding process can be used. the Timing control 83 also receives a signal from hydraulic system 42 indicating when the pressure plates have moved close enough together that the upsetting process begins. If the time control 83 and the control circuit 54 are switched on (such as is explained in more detail below), the time control reacts to this Signal of the hydraulic system to continue the energy transfer one to allow predetermined, adjustable time, after which the timing control the ignition control circuit 51 influenced so that the transmission of energy is switched off.

The hydraulic system 42 and the hydraulic cylinder 43 act in Response to an initial signal from the control panel C (Fig. 2) comes here to begin burning by moving the platen 36 is moved in the direction of the stationary pressure plate 34. When the moving Plate 36 and the stationary plate 34 each other except for a predetermined distance have come close, the hydraulic system 42 initiates the upsetting process by the Cylinder 43 is operated so that it opposes the movable plate 36 with great force the stationary plate 34 pushes towards and thus presses the tape ends together. At the At the beginning of the upsetting process, the hydraulic system also sends a signal to the control circuit 54, which indicates that the upsetting process has started, and the deneit section initiates, during which the electrical power during the upsetting section the welding cycle continues.

One embodiment of the control system 54 is shown schematically in Figures 4a, 4b and 4c. Figures 4b and 4c show portions of the control circuit output logic 80, which control the operation of the Ignitron tubes, which generate electrical power forward to the realization of the welds.

Fig. 4b shows an output logic circuit which the phase position of the Ignitrons (i.e. the time in each AC half cycle at which these tubes begin to conduct) controls the conductivity at the requested time can be stopped abruptly. Fig. Sc shows the output logic circuit that begins with of the upsetting timing controller 83, thus selectively the control effect of the upsetting timing can be bypassed and negated in order to enable control of the time, while the electrical power is applied during the upsetting process> in Dependence on other signals generated by the control circuit 54 and which are shown in detail below.

The circuit diagram in Fig. 4c encloses two terminals 100 and 102, the are connected to the upsetting timing controller 83.

The upsetting timing controller 83 is preferably a known type electronic time control. The duration of the time cycle of the timer 83 is an increasing function of the total amount of electrical resistance between terminals 100 and 102. If the resistance between terminals 100 and 102 is negligible is small, the length of time is practically zero and the timing controller 83 has substantially no effect. A potentiometer 104 is connected between terminals 100 and 102, which has an adjustable resistance. A normally open relay contact 106 is via the two-position switch 110 parallel to the potentiometer 104 between the Terminals 100 and 102 switched.

The circuit according to Fig. 4c can optionally be preset so that it runs either in automatic or in manual mode. In manual mode the circuit is preset so that it has the adjustable resistance of the potentiometer 104 used in the timing control 83 and used to determine the duration of the upsetting cycle, which is controlled by the time control to regulate. Alternatively, automatic Operating mode the circuit is preset so that the effect of the potentiometer 104 is bypassed by a secondary circuit, so that only the state of the relay contact 106 determines the length of the upsetting cycle. The state of the relay contact 106, the will be discussed below is controlled by the operation of the control circuit 5 4.

When the switch 110 is in the position shown on the right in FIG. 4c is moved, the branch of the circuit containing contact 106 is opened, with which the state of this contact is ineffective. In these circumstances, the The time control 83 is always operated by the one set on the potentiometer 104 Resistance controlled.

In the automatic mode of operation, the switch 110 is shown in FIG. 4c after moved left. Under these circumstances, the state of contact 106 determines whether the potentiometer influences the circuit of the timing control 83 or whether it is through the relay contact is short-circuited.

When operating in automatic mode with switch 110 in the left position, the potentiometer 104 is preferably to the highest possible Resistance set, whereby an upsetting cycle would be achieved with a period of time which is greater than any reasonable sweat effect, if that Potentiometer 104 could act on the circuit of the timing control 83 it is ensured that the time control does not occur earlier in the automatic operating mode responds than until the contact 106 is closed, which is through the Effectiveness of the control circuit 54 is determined. If the timing controller 83 before Closing the contact 106 would toggle, it would switch to the automatic mode of operation disturb and impair the circuit.

As will be fully explained later in detail, bring other sections of the control circuit 54 the contact 106 to take its normally open position, before it's time to finish the weld cycle and they bring the Contact 106 to be in a closed position when required The duration of the upsetting portion of the welding cycle has expired, i.e. when the Welding cycle is over.

Fig. 4b shows a circuit for an additional ignition control circuit 51 to ignite the Ignitron interrupters in the correct phase and to do so to bring the application of power to the strip ends after the end of the upsetting cycle switch off abruptly. The purpose of this property is to be a very abrupt one To help achieve termination of the service charge and is therefore necessary because the timer inherently creates a time delay in its operation which takes effect after the contact 106 is closed. When the timing would be used alone at the end of the charging process would be one unwanted delay in this termination the result.

This circuit has two terminals 112 and 114, which are connected to the ignition control 51 are connected. The phase position of the Ignitron tubes is determined by the magnitude of the Resistance controlled, which is present between terminals 112 and 114. if As the resistance between terminals 112 and 114 increases, the ignitrons will be in known way so changed in their phase position that they are in each cycle of the AC voltage supply a decreasing proportion of performance by the Ignitrons on the Let the primary circuit of the transformer through, thereby reducing the application of power control on the metal to be melted.

The resistance between terminals 112 and 114 is set by an adjustable Potentiometer 116 determines which is in series with a resistor 120 between the terminals 112 and 114 lies. The resistance between these terminals is continued by the State of a switch 122 and a normally open relay contact 124 determined, which are parallel to resistor 120.

The circuit of Fig. 4b provides a manual control of the tape ends exercised power loading before and he sees an automatic mode of operation before, in which the application of power in the same way to a predetermined Amount can be adjusted. The circuit also helps keep the power loading quickly terminated by the ignitrons at the end of the upsetting portion of the welding cycle will.

In accordance with the manual mode, the switch 122 set in the right position, whereby it has both the effect of the resistor 120 and the contact 124 short-circuits. In these circumstances is the only one substantial resistance between terminals 112 and 114 due to the setting of potentiometer 116 caused resistance.

The potentiometer can be used to change the resistance between the Terminals 112 and 114 are set to be a predetermined fraction of that of of the power supply to get possible power. With automatic operation the switch 122 is placed in its left position, with the voltage across the Resistance 120 is determined by the state of the normally open relay contact 124 will.

In the automatic operating mode, the potentiometer 116 is set so that that it is the minimum amount of resistance between terminals 112 and 114 yields. In these circumstances the resistance moves between the Terminals 112 and 114 between two values, i.e. essentially the value zero and the resistance of resistor 120.

In the automatic operating mode, the normally open relay contact is 124 operated by the control circuit 54 so that the resistance between the terminals 112 and 114 upon opening of the contact 124 at the time of the expiry of the upsetting section the welding cycle increases abruptly. In this operating mode, contact 124 is in front the process of the upsetting section of this cycle is kept closed, whereby the Resistor 120 is shorted. When the upsetting cycle is to be ended, the contact 124 assumes its normally open position, which effectively the resistor 120 in the branch of the circuit between terminals 112 and 114, whereby the Resistance between these terminals rises abruptly and the Ignitrons in one such Phased so that their power delivery to the primary circuit of the Abort transformer.

The operation of contacts 106 and 124 is controlled by the actuation, respectively controlled by two relays 130 and 132 (Fig. 4a).

When the relay 130 is actuated, the normally open contact takes place 106 its closed position and when the relay 130 drops out, the contact takes 106 to its normal open position. The same happens when the relay is activated 132 the normally open contact 124 is closed and when the relay 132 drops out it takes contact 124 returns to its normally open position.

The relays 130 and 132 are activated by the output of the adding amplifier 82 controlled in conjunction with two diodes 134 and 136. When the output signal of amplifier 82 is relatively low as it was prior to the completion of the upsetting cycle of the Is the case, the relay 130 has dropped out, with which the contact 106 assumes its normally open state and the relay 132 is energized, whereby the contact 124 assumes its closed position.

The output signal of the amplifier 82 changes after the expiry of the Duration of the upsetting portion of the cycle from a relatively low value to a relatively high value.

When the output of amplifier 82 goes high, the relay will 130 attracted, whereby the contact 106 closes and the relay 132 drops out, whereby contact 124 opens. This actuation brings the resistance between terminals 100 and 102 to drop abruptly, leaving the upsetting timing 83 emit a signal to the ignition control 51, which switches off the Ignitrons and ceasing the application of power to the ends of the ribbons. Additionally The opening of contact 124 leaves the resistance between terminals 112 and 114 increase abruptly, which serves that the phase position of the Ignitrons abruptly so that changes the passage of power from the power source to the one to be welded together Metal ends abruptly terminated.

The effect of amplifier 82 and the state of its output is provided by the memory circuit 84, the input logic circuit 86 and the percent control circuit 90 determined. The memory circuit 84 includes a capacitor 140 and in parallel in addition a resistor 142. The upper terminal of the capacitor 140 and the resistor 142 is connected to the non-inverting input 146 of the addition amplifier 82.

The input logic circuit includes a relay contact 150 and a protective resistor 152 connected to the inverting input 154 of the amplifier 82 are connected via a potentiometer 155, which forms the percent control circuit 90, how will be explained later.

The output of the energy monitor 52, a voltage that the Represents the total amount of energy collected in the welding cycle, is applied to the input logic circuit at terminal 160.

The memory circuit 84, the input logic circuit 86 and the percent control circuit 90 work together to cause amplifier 82 to be a relatively low Output during the weld cycle results before the upsetting portion of the cycle is over and bring the amplifier 82 at the end of the upsetting cycle time to produce a relatively high output signal. The time at which the output signal of the amplifier 82 changes its state and consequently the mode of operation of the remainder of the control circuit 54 completes the upsetting cycle depends on the ratio the amount of energy applied during the upsetting cycle and during the burn-off cycle away.

At the beginning of the weld cycle is contact 150 from later for explanatory reasons in closed position. The voltage signal from the energy monitoring device 52, which represents the instantaneous accumulated energy value of the welding cycle, is applied across resistor 152 to the parallel RC combination consisting of the capacitor 140 and the resistor 142 consists. This increases the voltage at the upper terminal of the capacitor 140 in accordance with that of the energy monitor 52 voltage signal present at terminal 160. Essentially the entire way applied voltage is also applied to the non-inverting input 146 of the amplifier 82 created. During this part of the cycle, only a fraction of the Terminal 160 voltage appearing at the inverting input 154 of the amplifier applied because the potentiometer 90 is at some intermediate value, so that less as the total voltage drop between the right terminal of resistor 152 and Earth appears on the inverting input. Therefore generated during this section of the cycle of amplifiers 82 have a relatively low output signal.

When the burn-off portion of the weld cycle is completed, the Relay contact 150 placed in its normally open position. This will be effective the storage circuit of the voltage applied to terminal 160, that of the energy monitoring 52 comes from, cut off the voltage on the upper terminal of the capacitor 140 remains essentially constant as it only runs at a relatively slow speed is reduced via the resistor 142. While doing so the tension on the non-inverting Input 146 remains relatively constant, the voltage at the inverting input 154 will continue to rise, as will the continued rise of the signal from the power monitor 52, which corresponds to the continued integration of the throughout the welding cycle corresponds to the applied energy value.

It can thus be seen that the voltage at the inverting input 154 only then becomes equal to the voltage at the non-inverting input 146 after the Signal at terminal 160 continues to rise to a value by a predetermined Fraction of the value of the signal on terminal 146 at the end of the burn-off section exceeds. This predetermined fraction is determined by the setting of the potentiometer 90 determines which represents the percent control.

The circuit described in FIGS. 4a, 4b and 4c thus works together, to stop the application of energy to the welded ends of the tape, when the sum of the energy supplied during the upsetting cycle reaches a value which is a predetermined direct proportional function of the in the burning section of the Cycle is applied energy.

The action of contact 150 is through a simple relay arrangement which is connected to the hydraulic system 42. This becomes schematic shown in Fig. 4d. This circuit consists of a normally closed mechanical Contact 170 connected to the hydraulic system and on its movement responds accordingly in open or closed position. The mechanical contact 170 is designed so that it is opened when the hydraulic system 42 the movable platen 36 at a predetermined distance from the stationary platen 34 brings. In series with contact 170 is a diode 172 and an electrical relay 174 switched. Normally the contact 170 is closed, creating a current can flow from earth to a terminal 176 which is at negative potential and the relay 174 energizes. This energization of the relay leaves contact 150 closed Assume position and allow the continued charge build-up in the capacitor 140 during the burning process. When the burning process is complete, the Contact 150 open, so that the charge of capacitor 140 is retained and does not increase any further.

Referring to Figures 5a, 5b, 5c and 5d, there is another embodiment of the control circuit 54 shown. In this alternative embodiment there is a memory and a percent control circuit which differ from the circles shown in Fig. 4a. The percent control circuit 90 allows the setting of the fraction of the burning energy that is used during the upsetting process can be applied according to one of two previously set ratios. The memory circuit and associated circuitry contain facilities for a longer storage of the memory signal than is possible in the circuit according to FIG. 4a is.

The output logic circuit shown in Figures 5b and 5c is essentially identical to the structure and mode of operation of the output logic circuit in Figures 4b and 4c. Likewise are relays 130, 132 and the diodes 134 and 136 are analogous in structure and mode of operation to the components shown in FIG. 4a and the same is true of summing amplifier 82. These components are provided with the same reference numbers as for the analog components in 4a-4c are shown.

In this embodiment, the memory circuit contains an operational amplifier 180, which is switched in such a way that it controls the energy monitoring device 52 at terminal 182 through normally open contact 184 and terminal 185. The output of amplifier 180 is to non-inverting input 146 of the amplifier 82 is connected. The output value of the energy monitoring device 52 is similarly to the inverting input 154 of the amplifier 82 via a Terminal 186 and percent control circuit 90 applied.

After the start of the welding cycle, the output value of the energy monitoring device is used 52 applied to terminals 185 and 186. During this section of the cycle and the normally open contact 184 is kept closed until the end of the burn-off cycle, as described below. During this time, the output value of the operational amplifier increases 180 as a function of the voltage output signal indicating the energy value, the is applied to terminal 182. The output value of the amplifier 180 is applied to the terminal 146 of amplifier 82 is applied. The output value of the energy monitoring device 52, which appears at terminal 186, is applied to the inverting input 154 of the Amplifier 82 applied after being attenuated by percent control circuit 90 has experienced. In this state, the amplifier 82 generates as in the previous one discussed Performs a relatively low output signal that contacts 106 and 124 in in a manner analogous to that described in the previous version.

Upon completion of the burn cycle, contact 184 may be normal assume the open position and the amplifier 180 produces an output signal that remains constant and a function of during the burn-off portion of the weld cycle is the total energy supplied to the workpieces. The one at input 154 of the amplifier However, the applied tension continues to rise during the upsetting section until it reaches a value which makes the output of amplifier 82 its state lets change. This takes place when the signal applied to terminal 186 which represents the integrated energy of the entire welding cycle, as far as it increases, that even after attenuation by the percent control circuit 90, the signal at the Terminal 154 equals the signal applied to terminal 146. This condition occurs when the voltage at terminal 186 exceeds the voltage at the output of the amplifier 180 by a predetermined fraction, the predetermined fraction depends on how the percent control circuit 90 is set.

As can be seen, the circuit of FIG. 5a operates in the same way like that shown in Fig. 4a and controls that applied during the welding cycle Energy.

Since the output of the amplifier 180 for a long period of time can remain substantially constant, a memory reset circuit is provided, to reset its value to zero when a weld cycle is completed and / with it to prepare for the effect of the storage circuit during the next cycle. The memory reset circuit includes normally closed contact 190 and a relay 192 (Fig. 5d), which in Row with one contact 194 and a diode 196.

The left terminal of contact 194 is at a positive voltage tied together. The contact 194 is a mechanical contact that is dependent on the actuation of the hydraulic system opens at the end of the upsetting cycle, whereby the Relay 199 drops out and contact 190 closes.

Closing the contact 190 changes the feedback of the operation amplifier 180 so that its output value returns to zero by discharging a capacitor 195.

Contact 184 is controlled by relay 200 which is in series with a normally closed mechanical contact 202 and a diode 204 (Fig. 5d). A negative voltage is connected to the left terminal of contact 202. The normally closed contact 202 is operated by the movable pressure plate 36, as soon as this comes to a distance from the stationary plate 34 which is smaller as a predetermined value (indicating that the burning process has ended is), whereby the contact 202 is opened, the relay 200 drops out, which in turn contact 184 returns to its normally open position. This described above Actuation separates the Sneicherkreis in such a way that it does not show any further signs of energy consumption receives and maintains the output of amplifier 180 constant in the welding cycle stay and represent the energy of the burn-off section.

The percent control circuit of this alternative version can be divided into two different ranges can be set which the voltage ratio at the terminals 146 and 186 determine at which the output of amplifier 82 is its state changes. This is useful because of the range of ratios required of upsetting and burn-off energy when welding alloys and when welding differs from normal steels.

The percent control circuit 90 includes a selector switch 210 for selection the areas for alloy welding and normal steel welding. The percent control circle also includes a pair of resistors 212 and 214 and two potentiometers 216 and 218.

The switch is used to operate when welding alloy metals 210 moved to the left position. Under these circumstances, it occurs at the clamp 186 applied voltage through potentiometer 218 and resistor 214 and eventually appears on terminal 154 of amplifier 82. More normal when welding Steels the switch 210 is moved to the right, whereby the potentiometer 218 and the resistor 214 is no longer involved in the circuit and takes its place the potentiometer 216 and the resistor 212 step. If the settings of the Potentiometers 216 and 218 are different, determines the position of switch 210, which of the two set ratios of compression energy to burn-off energy is effective for the respective welding cycle. This property makes a system with greater flexibility and allows the two potentiometer values to be preset, which can then be selected by simply moving the switch 210.

The description thus shows an apparatus and a method for Execution of flash butt welding. The device moves adjacent sections of workpieces against each other, they are charged with electrical energy, so that a heating takes place in a burning process, after which the surfaces during a Upsetting processes are pressed together, while the application of electrical Energy is maintained for a predetermined period of time. One device is provided by the amount transferred to the workpieces during the welding process monitor electrical power, and a Control circuit to the during the upsetting process applied electrical energy to a predetermined Limit value, which is a function of the energy used during the burning process was applied. An energy recorder produces an indication of the Amount of energy given off to the workpieces during the welding process.

- patent claims -

Claims (33)

Claims 1. Welding device, thereby g e k e n n n z e i c h -n e t that a) a device is provided which emits energy in order to produce a weld between To effect workpieces in a plurality of steps, b) a device for detection the amount of energy released in one of the steps is provided and c) that one Control device is connected to the energy delivery device and the recording device in order to depending on the amount of energy given off in another of the steps of the energy released in the one step. 2. Welding device according to claim 1, characterized in that g e -k e n n z e i c h n e t that a) the welder is a flash butt welder to make welds to cause in a burning process and a upsetting process and b) that the control unit Switching devices for limiting the energy released in the upsetting process as a predetermined function of the energy emitted in the burning process. 3. Welding device according to claim 2, characterized in that g e k e n n -z e i c h n e t that the predetermined function is a direct relationship. 4. Welding device according to claim 2, characterized in that g e k e n n -z e i c h n e t that the control unit also has a setting circuit for changing the specified Function includes. 5. Welding device according to claim 3, thereby g e k e n n -z e i c h n e t that the control unit has a setting circuit for changing the predetermined function includes. 6. Flash butt welding device with a device for dispensing electrical and mechanical energy on workpieces to create a weld between to effect this in accordance with a burn-off and an upsetting process, and with a monitoring device for detecting during the burning process and Amounts of electrical energy given off during the upsetting process, thereby g e k It is noted that an energy recorder works with the recording device connected to produce a display output of the amount of electrical energy, which is given off during welding. 7. Welding device according to claim 6, characterized in that g e k e n n -z e i c h n e t that the display output is a graphical representation of the integral value of the includes electrical energy released during welding over time. 8. Process for applying electrical energy to workpieces, around a weld between the workpieces in a sequence of a multitude of procedural steps, in that a) a first step of the welding process is carried out, b) that the amount of electrical energy released during the first step of the welding process is detected, c) that a second step of the welding process is carried out and d) that the amount dispensed during the second welding process step of electrical energy as a function of that during the first welding process step submitted Energy amount is limited. 9. The method according to claim 8, characterized in that g e k e n n -z e i c h n e t that a) burn-off is carried out as the first welding process step, b) that upsetting is carried out as the second welding process step and c) that the limiting is carried out so that the amount of electrical energy that is dispensed during upsetting, in a predetermined dependence on the The amount of electrical energy given off during burning is limited. 10. The method according to claim 9, characterized in that g e k e n n z e i c h -n e t that direct proportionality is used as the predetermined dependency. 11. The method according to claim 10, characterized in that g e k e n n z e i c h -n e t that the predetermined dependency is varied adjustably. 12. Flash butt welding device with a device for delivering electrical Heating energy and mechanical energy to burn off and then subsequent upsetting to cause workpieces to be welded together, characterized in that a) the amount of electrical energy given off during burning with an energy monitoring device is detected and b) that the amount emitted during the upsetting electrical Energy through a control circuit connected to the energy monitoring device is limited depending on the amount of electrical energy that is consumed during the Burning is given off. 13. Welding process with successive welding cycles while each of which is a group from a sequence of groups of at least two workpiece surfaces are welded together according to the flash butt welding process, thereby g e k It is noted that a) first a burn is carried out, that i) the workpiece surfaces are moved against each other and ii) an electrical one Voltage is applied between the workpieces during the movement so that the Surfaces are heated by arcing, b) that the released during burning Amount of electrical energy is monitored and c) thereupon a compression thereby is carried out that i) the workpiece surfaces are pressed against each other and ii) continued electrical voltage between the workpieces for a period of time which is a function of the amount of electrical energy used during the burning was released. 14. Welding system for performing a flash butt weld cycle of workpiece surfaces, in that it is not indicated that a) a device for performing the initial burn, which consists of i) a device for moving the workpiece surfaces against one another and ii) from a device for Applying electrical energy to the workpiece surfaces during movement consists in order to cause the surfaces to be heated with an electric arc, b) a device is provided for continuous monitoring of the amount of electrical energy that released during the weld cycle including burn-off will, by generating a total energy output that is equal to the instantaneous Represents the integral value of the electrical energy emitted during the cycle and c) a device is provided for subsequently carrying out the upsetting, i) a device for pressing the workpieces against one another after they have been burned off and ii) a control circuit for continuing the delivery of electrical energy includes the workpieces during a predetermined period of time within the upsetting wherein the predetermined period of time is a function of that emitted during the burn Amount of electrical energy. 15. System according to claim 14, characterized in that it is e k e n n z e i c h -n e t that an energy recorder is connected to the monitoring device in order to an indication of the amount applied to the during burning and upsetting To generate workpieces given off electrical energy. 16. The system as claimed in claim 14, characterized in that it is e k e n n z e i c h -n e t that a device for the adjustable variation of the predetermined time function is provided. 17. System according to claim 14, characterized in that it is e k e n n z e i c h -n e t that the control circuit comprises a device with which the predetermined time function is set as direct proportion. 18. System according to claim 14, characterized in that it is e k e n n z e i c h -n e t that the control circuit includes: a) a storage circuit that is so with is connected to the energy monitoring device that it stores a signal that the Represents the amount of electrical energy given off during the burning process, b) a comparison circuit that connects to the energy monitoring device and the memory circuit is connected in such a way that it relates to the output of the stored signal in relation to the Total energy output and c) output logic circuit shown in The dependence of the comparison circuit limits the electrical energy output, if the comparison circuit indicates that the value of the output signal of the monitoring device, which represents the total energy output, changes the value of the secured signal exceeds a predetermined fraction of the stored signal value. 19. The system as claimed in claim 18, characterized in that it is n -z e i c h n e t that an input logic circuit is provided between the energy monitoring device, the memory circuit and the comparison circuit is connected to the memory circuit disconnect from the energy monitoring device at the end of the burnout, while delivering the total energy output to the comparison circuit during continues throughout the welding cycle. 20. System according to claim 18, characterized in that g e k e n n -z e 1 c h n e t that a) the comparison circuit has an operational amplifier with an inverting Input and a non-inverting input includes and b) that the memory circuit comprises a capacitor which is connected so that it Receives the output signal of the energy monitoring device and assumes a voltage, which is a function of the total energy output, the capacitor being so is connected that he applies this voltage to the non-inverting input. 21. System according to claim 20, characterized in that it is not possible to use it that the input logic includes a relay contact between the energy monitoring device and the capacitor is switched and that the relay contact is controlled in such a way that he removes the capacitor from the energy monitor at the end of the burn-off section of the welding cycle. 22. The system as claimed in claim 18, characterized in that it is e k e n n z e i c h -n e t that a) the memory circuit comprises an operational amplifier, which the output signal of the energy monitoring device and generates an output signal that has a function of the output signal of the energy monitoring device and b) that the comparison circuit comprises an addition amplifier whose non-inverting input connects to the operational amplifier output is connected and at its inverting input the total energy output signals issue. 23. The system as claimed in claim 22, characterized in that it is e k e n n z e i c h -n e t that a Proeent control circuit is provided to the predetermined function adjust that this circuit contains at least two potentiometers, each in series between the energy monitoring output and the inverting one Input are switchable. 24. System according to claim 18, characterized in that it is not possible to use it that a percent control circuit is provided which comprises an i? otentiometer, the connected between the energy monitoring device and the non-inverting input is to set the predetermined function. 25. Welding system with a structure, the workpiece surfaces to be united moved up to a close distance to each other, with a device for the delivery of electrical Energy to weld between the workpieces in a multitude of welding steps perform with a device to measure the amount of during the welding process to control delivered energy and with a device that the amount of on measures the electrical energy emitted by the workpieces during the welding process and generates a corresponding output signal, thereby g e k e n n -z e i c h n e t that a) a device (84,52) is provided to each time the amount of in one of the welding steps to record electrical energy emitted for itself and b) that a control circuit (54) is provided which is so associated with the energy delivery device and the separate monitoring device is connected to the amount of in a further step, depending on the electrical energy output from that detected separately from the monitor as being dispensed in the one step electrical energy controls. 26. The welding system as claimed in claim 25, characterized in that it is e k e n n -z e i c h n e t that a) the welding device is a flash butt welding device for Execution of welds with burning off and upsetting is and that b) the control device comprises switching devices, which during the upsetting delivered electrical energy in a predetermined function of the during the Burning off electrical energy is limited. 27.Schweißsystem according to claim 26, characterized g e k e n n -z e i c h n e t that the given dependency is direct proportionality. 28. Welding system according to claim 26 or 27, g e k e n n -z e i c h n e t by a setting circuit (90) for varying the predetermined dependency. 29. The welding system as claimed in claim 25, characterized in that it is e k e n n -z e i c h n e t that a) the device for the delivery of electrical energy comprises devices, transfer the electrical energy to the workpiece surfaces during their movement, to achieve heating of the surfaces by arcing, b) that the energy monitoring device a device for the continuous monitoring of the entire welding process electrical energy output has, c) that a device for carrying out the upsetting is provided after the arc heating, which comprises: i) the control circuit with a device to move the workpiece surfaces against each other after arc heating to press, and ii) the control circuit with switching parts (86,82), which is the continuation the energy output on the workpieces only during the predetermined time of upsetting control, the predetermined time on the amount of electrical energy that was applied during arc heating. 30. Welding system according to claim 29, characterized in that there are g e k e n n -z e i c Note that the control circuit comprises: a) a memory circuit (34) which depends on the energy monitoring device and sends a signal that the amount represents the electrical energy given off during burning, b) a Comparison circuit (2) with the energy monitoring device and the Sneich circuit is connected so that the value of the stored signal with the energy output signal of the energy monitoring device is compared and c) an output logic (80), which terminates the delivery of electrical energy in response to a signal from the comparison circuit, when the comparison circuit indicates that the value of the from the energy monitor output signal the value of the stored signal by a predetermined Exceeds fraction of the stored signal value. 31. Welding system according to claim 30, characterized in that it is e k e n n -z e i c h n e t that an input logic circuit (86) between the energy monitoring device, the storage circuit and the comparison circuit is connected to the storage circuit disconnect from the energy monitoring device at the end of the burnout, while the delivery of the energy output signal from the energy monitoring device to the comparison circuit remains continued throughout the welding cycle. 32. The welding system as claimed in claim 31, characterized in that it is a g e k e n n -z e i c h n e t that a) the comparison circuit has an operational amplifier with an inverting and a non-inverting input and b) that the storage circuit a capacitor (140) connected to have an output signal from the energy monitoring device to generate a voltage that is a Function of the value of the energy signal is generated by the energy monitoring device is generated and that the capacitor is connected so that this voltage across the non-inverting input is present. 33. Welding system according to claim 32, characterized in that there is a g e k e n n -z e i c h n e t that the input logic includes a relay contact (150) between the Energy monitoring device and the capacitor is connected, the relay contact the capacitor from the energy monitoring device at the end of the burn-off section of the welding cycle.