Abstract: An arc welding process is provided with a preheating step in which a consumable wire electrode is heated prior to insertion into the electrode stick-out region. This is accomplished by the circulation of current from a preheating power supply through a segment of the wire. Both gas-metal and gas-tungsten arc welding processes are disclosed, along with apparatus used in these processes.

Abstract: A method of controlling the output of a power source in consumable electrode arc welding in which a short circuiting phase and an arcing phase alternately take place between a consumable electrode and a workpiece in a shielding gas atmosphere, the method being characterized by repetition of a cycle of operation consisting of: a first stage of maintaining the output welding current at a first value of a relatively low level upon establishment of a short circuit across a gap between a consumable electrode and a workpiece; a second stage of maintaining the welding current at a second value of a relatively high level succeedingly to the first stage; a third stage of lowering the welding current to a third value of a low level upon detection of necking as a premonition of rupture of short circuiting molten metal between the electrode and workpiece; a fourth stage of, upon generation of an arc across a gap between the electrode and workpiece subsequent to the third stage, maintaining the welding current at a fourth

Abstract: A method and a device for controlling a welding power supply, employing a control device essentially including a first switch means consisting of at least one switch in element to be turned on and off to control the output current of the power supply, second switch means adapted to be inserted in a welding current attenuating path when the first switch means is in off state, and an impedance means consisting of at least one impedance element connected parallel with the second switch means.

Abstract: The present invention relates to a method for measuring the free wire length in hot-arc or short-arc MIG/MAG welding by making use of the typical behavior of the current or the voltage in the bead short-circuit situation, in which the voltage rises in different ways depending on the free wire length. The phenomenon can be used for measuring the free wire length.

Abstract: A gas shielded arc welding method in which a non-consumable electrode and a filler wire are respectively connected to independent DC power sources and the non-consumable electrode is located in a preceding position, feeding the filler wire from behind the electrode. The non-consumable electrode is held in a forwardly tilted position to form an angle smaller than 85.degree. with a workpiece, and the non-consumable electrode and filler wire are applied with inverse electric currents to thereby control the arc direction for formation of sound joints. A welding apparatus is also disclosed which is capable of effecting arc extension control and oscillation simultaneously.

Abstract: This invention is a closed loop control system for controlling the speed at which a consumable electrode is advanced toward a workpiece, for short-circuit metal transfer arc welders. Proportional plus integral feedback is provided for controlling the electrode feed motor speed to reduce the error between commanded and measured time periods between successive weld short-circuit onsets. Speed controls for both direct current and alternating current electrode feed motors are included.

Abstract: An electronic welding energy source comprises interconnected control and power circuits together with independently operable circuits for setting the static and dynamic characteristics respectively of the source.

Abstract: An electric arc welder has a current-conducting means which can supply welding power to an arc along a first volt-ampere curve, has a second current-conducting means which can be paralleled with the first current-conducting means to supply welding power to that arc along a second and distinctly-different volt-ampere curve, has a voltage-sensing circuit which senses the arc voltage, and has a control circuit which automatically and virtually-instantaneously shifts the supplying of welding power from a point on the first volt-ampere curve to a point of essentially-equal potential on the second and distinctly-different volt-ampere curve when the voltage-sensing circuit senses that the arc voltage has fallen below a predetermined value.

Abstract: A method and apparatus for short-circuit MIG welding is described. The apparatus comprises a power supply electrically connected with electrode wire and a workpiece in use; and electrode wire feed means. Monitoring means is provided for monitoring the ratio (M) of one of the mean and successive integral of the arc duration to the corresponding one of the mean and the successive integral of the short-circuit duration. The welding process can be monitored by monitoring the ratio (M).

Abstract: An AC-DC welding power supply includes a main transformer in which the primary windings are partially decoupled from the secondary windings to provide a small amount of reactance on the output side of the power supply. A current regulating circuit and a current sensing shunt are mounted between two or more secondary windings for isolation. The current regulating circuit is controlled by a firing control circuit. An adjustable output feedback control circuit, including the shunt and a mixing circuit, provides a mixed current/voltage signal to the firing control circuit according to the current through and voltage across the secondary windings. The power supply output is adjustable from constant voltage through constant current. The output terminals of the secondary windings are connected directly to AC supply terminals and also to DC supply terminals through a rectifier circuit.

Abstract: The specification describes a control unit for use with the welding gun of an arc welding assembly. A single adjustable means in the welding gun effects changes in the control unit to regulate welding voltage as well as the speed at which the electrode wire is fed to the welding site.

Abstract: In a pulse welding method, an optimum pulse current waveform defined by the amplitudes of the current pulse and base current and the width of the current pulse is maintained throughout the welding operation while the average welding current is varied by changing the frequency of the current pulse.

Abstract: The impulse welding device includes a transistor circuit which is operated by an impulse generator. The power transistors of the transistor circuit are operated alternately in the blocked condition and in the conducting condition. The transistor circuit is connected to a direct current power source in series with the arc which is created between the welding electrode and the work piece to be welded. The transistor circuit is shunted by an ohmic resistor which allows a spacing current to flow through the ignited arc during the impulse pauses. Since the power transistors are substantially completely blocked during the impulse pauses, the power loss will be decreased.

Abstract: The invention relates to a process and an apparatus for metal arc welding with a consumable electrode. A pulsating current is supplied to the electrode from a constant current source. During the interpulse periods between pulses there flows a minimum current which is at least sufficient to maintain the arc. The switch from pulse current to interpulse current occurs as a function of the arc voltage, with switching to pulse current occurring if a minimum voltage is detected and to interpulse current occurring if a maximum voltage is detected. Compared with conventional metal arc welding with a consumable electrode, this method offers the advantage of a better welding quality.

Abstract: A short circuit transfer arc welding machine including a wire electrode which is fed towards a base metal, a DC source for applying a voltage across the base metal and the wire electrode, a switching element for interrupting the voltage, a voltage detector for detecting a voltage developed across the base metal and the wire electrode, a first comparator for determining when a detection voltage outputted by the voltage detector reaches a voltage value corresponding to the short circuiting of the base metal and wire electrode, a second comparator for determining when the detection voltage of said voltage detector reaches an arc discharge voltage, and a switching element control circuit for closing the switching element in response to a signal from the first comparator and for opening the switching element in response to a signal from the second comparator.

Abstract: An arc blowing control method and apparatus for use in a pulse arc welding system for preventing the extinction of the welding arc in the presence of current fluctuations or the like, thus preventing splattering of molten welding material and resulting in a smooth and continuous welding bead. A detection circuit is provided for electrically detecting the occurrence of a so-called stepped leader phenomenon during pulse arc welding and for generating a stepped leader signal accordingly. A switching unit is operated in response to the stepped leader signal for switching from a normal arc signal output to an arc blowing blocking signal output for a predetermined time. An arc blowing blocking circuit operates in response to the arc blowing blocking signal for effecting arc blowing suppression operations.

Abstract: A DC welding device is provided with an adder which sums the signals from a base current setting circuit and a shorting current setting circuit and applies the same to a welding current control unit. When a short circuit occurs, the shorting current circuit outputs a gradually increasing signal until the short is removed, whereupon a gradually decreasing signal, which reaches zero after a predetermined time, is output.

Abstract: A multi-purpose welding power supply to provide different modes of welding from a single unit. Two positive output terminals are provided, one for low amperage welding up to about 300 amp which includes an inductor and slope resistor and one for high amperage output up to about 600 amp which bypasses the inductor and slope resistor in the low amperage circuit. A pulsing circuit is provided to impose on the 300 amp output either 60 pps or 120 pps pulses on a standard direct current background. A variable pulse width control circuit is integrated with the pulsing circuit to vary the pulse width. A "hot start" feature is included with the 60 pps welding mode to provide 120 pps pulses for an initial pre-selected time period.

Abstract: The user of electric arc welding equipment is provided with audible feedback signals which provide useful information relating to the output current and voltage of the welder. An audio tone is generated and is frequency modulated by a signal which corresponds to welder output voltage. The tone is amplitude modulated by a signal corresponding to output current thus providing the user with a synthesized feedback signal having a voltage-proportional pitch and current-proportional volume. Additional modulation means are disclosed for introducing a current-proportional warble component to said tone.

Abstract: A power source includes first and second control circuit for controlling the current provided during short-circuit and arc intervals, respectively. A transistor in series with the power supply is controlled in response to either of the control circuits.

Abstract: A hot-wire arc welding apparatus comprises a non-expendable electrode, means for supplying a current to initiate an arc between the nonexpendable electrode and a workpiece, an arc current control means for controlling the current from the supplying means, a wire feed means for feeding a filler wire into the arc, a wire feed control means for controlling the wire feed means to feed the filler wire at a given rate of feed, a voltage applying means for applying a voltage between the filler wire and the workpiece, a wire voltage control means for controlling the voltage from the voltage applying means, and a reference voltage generator for generating an output voltage which increases gradually or incrementally with time, each of the arc current control means, the wire feed control means, and the wire voltage control means being connected to the reference voltage generator and responsive to the output voltage therefrom for controlling the operation thereof.

Abstract: A hot wire welding system including a non-melting metal electrode, a supply of filler metal to be fed to a weld puddle formed by an arc, a D.C. power source for supplying both an arc current and a filler metal heating current, a first control circuit for controlling the filler metal heating current with a constant voltage characteristic, and a second control circuit for controlling the arc current with a constant current characteristic. By eliminating one of the two power supplies which was required in prior art systems, a significant reduction in size and complexity is obtained.

Abstract: In a welding apparatus employing a switching element between a power source and a filler wire, a protection circuit operates to discontinue the function of the switching element when a short-circuit is detected between, for example, the filler wire and a welding electrode, so that the switching element is protected from damage due to an overcurrent.

Abstract: A four-electrode submerged arc welding process employs connections of four electrodes aligned in one row for alternating current source so that electromagnetic force Fx.sub.4 in a direction opposite to a welding direction acting upon a middle point of the arc from the rearmost electrode is within -25.ltorsim.Fx.sub.4 .ltorsim.-10 (N/m). The connections are preferably selected such that phase differences among currents applied to the three electrodes other than the frontmost or rearmost electrode are 120.degree., respectively, and a phase difference of the remaining frontmost or rearmost electrode is within 0.degree..+-.30.degree. relative to the furthermost electrode.With such connections of the four electrodes, the four-electrode submerged arc welding process remarkably prevents welding defects such as undercuts even at higher welding speeds.

Abstract: A method and device for automatically controlling welding conditions for use in an arc welding machine, wherein an ignition or turn-on phase of a thyristor is controlled by an output of a first potentiometer to which a fixed voltage is applied. A voltage difference between the movable terminals of the first and a second potentiometer which are coupled in parallel, is detected by a differential amplifier which outputs a signal corresponding to the difference to a motor. The motor turns the movable terminals of the second and a third potentiometer which are operated synchronously, so that the detected difference may be zero. The output of the third potentiometer to which a fixed reference voltage is applied, is stored in a memory in a recording mode.

Abstract: A method of welding metal articles along a joint using a non-overhanging torch, for example so called butt welds in a vertical or upright position, of the kind which uses a pulsed arc with gaseous protection and a cored wire electrode, is characterized by use of the following combination:(a) the "pulsed" arc is of the constant frequency pulse type with transfer of molten material at each pulse, without setting up any short circuit, viz. of the "spray arc" kind and (b) the cored wire electrode is of the basic kind.

Abstract: In a two electrode welding method wherein welding is carried out by means of arcs struck between two electrodes and a parent metal, the two electrodes being located in side-by-side, spaced-apart relation in a direction in which the welding surface advances and movable relative to the parent metal, a portion of the parent metal is preheated by the arc struck between the leading electrode and the parent metal, and a preheated portion is melted by the heat of the arc struck between the trailing electrode and the parent metal when the former has moved to a position above the preheated portion of the latter to provide a deposited metal. The method has particular utility in applications where metal of high heat conductivity, such as copper, is welded.

Abstract: In a three phase welding power supply, the three phase power is connected to a welding arc by a power control circuit having three conducting paths for straight polarity current and three conducting paths for reverse polarity current. The power control circuit comprises a three phase bridge rectifier circuit having eight bridge arms each including a silicon controlled rectifier with the bridge circuit being connected between the three phase power source and the welding arc which is in turn connected to the three phase power supply neutral. An inductor is connected across the direct current terminals of the bridge circuit so that arc current flows in one direction through the inductor regardless of the polarity of the arc current. The conducting paths are selectively activated at non-zero voltage points to conduct repetitive sequences of independent numbers of straight polarity half cycles of arc current followed by independent numbers of reverse polarity half cycles of arc current to the welding arc.

Abstract: A pulse arc welding machine in which the repetition frequency of the pulse currect is unaffected by the frequency of the power source and the mean value of the pulse current applied can be accurately controlled over a broad range while the arcing is maintained stable. A pulse peak current supplying circuit is connected in series with an arcing region formed between a consumable wire electrode and a material to be welded between the output terminals of a standard direct current source while a base current supplying circuit is connected in parallel with the pulse peak current supplying circuit. The pulse peak current supplying circuit and the base current supplying circuit are both composed of a switching element such as a transistor coupled in series with an inductive element. Diodes are provided for suppressing high voltage transients in the circuit.

Abstract: A method of arc welding is disclosed. Specifically, a method of pulsed direct current (DC) arc welding is disclosed wherein special pulses of positive direct current are used to weld together work pieces. The special DC pulses are capable of dissipating difficult to reduce oxides which may be present on the surfaces of the work pieces without using a flux. The method is especially useful for fluxless arc welding of aluminum, particularly thin wall aluminum tubing used in making heat exchangers for air conditioning systems.

Abstract: A pulse arc welding device includes a power source which produces a background current and pulse current imposed on it. A voltage drop across the arc is measured and when such a voltage drop deviates from a predetermined level, either one of background current, frequency of the pulse current and pulse duration of the pulse current is controlled to maintain the voltage drop across the arc constant.

Abstract: Method and apparatus for micro-arc brazing and welding of metal to metal or ceramic. The control of arc heat flux density is accomplished by controlling the ambient gas pressure and providing an argon, argon/5% hydrogen or other inert gas atmosphere. The discharge current is controlled so as to provide an arc which is operable at 100 microamps to 20 amps.Prior to welding or brazing, the work is cleaned by high frequency electrical discharge cleaning techniques using high energy ions from either the ambient gas or from an electrode. By providing a small amount of DC during the high frequency discharge a "tinning" capability is established.The welding or brazing may be formed in a closed chamber so that arc stabilization can be accomplished.

Abstract: A method of arc welding is disclosed. Specifically, a method of pulsed DC arc welding is disclosed wherein the pulse width of the current pulses are modulated to maintain a constant time averaged power flow to the work pieces being welded. This method of arc welding is especially useful with a type of pulsed DC arc welding wherein the ratio of peak current to maintenance current is maintained at a selected high value and the current is cycled in a time duration whereby oxides on the surface of the work pieces are dissipated as the weld is made. When used with this type of pulsed DC arc welding the present method is especially suited for fluxless welding of aluminum work pieces, such as thin wall aluminum tubing used in making heat exchangers for air conditioning systems.

Abstract: In a welding apparatus having a plurality of electrodes and adapted for carrying out welding operation on a workpiece by alternately supplying currents to the individual electrodes through switching elements, an apparatus and method of controlling the currents supplied to the electrodes, comprising selecting the values of the currents supplied to the individual electrodes depending on the material of the workpiece, and carrying out the welding operation on the workpiece by alternately supplying the currents of the selected values to the individual electrodes respectively through the switching elements. The method is featured by the fact that the ratio between the individual currents is selected under the condition that the sum of the values of all the currents is maintained at a predetermined value.

Abstract: A method and apparatus for forming a spherical shape on the end of an aluminum wire using a relatively low voltage across an arc gap to heat the end. Because the voltage is below the minimum sparking potential, a high voltage impulse is superimposed on the electrode to ionize the gas therebetween and initiate the arc. The gap may be in a protective environment such as an inert gas to prevent the formation of additional oxide. The wire may then be used in an aluminum ball bond.

Abstract: In a TIG welding process with controlled welding current pulses, DC current pulses with the frequency set at from tens to hundreds Hz (most preferably from 30 to 300 Hz) are fed to an electrode and current pulses are also fed to a filler wire so that an arc is caused to swing, whereby a large pool of molten metal can be maintained in a positive and stable manner due to the high arc pressure obtained when the welding current pulses at from tens to hundreds Hz is used.

Abstract: A regulated constant current is supplied to a welding load by an SCR power supply having an SCR rectifier network interposed in series between the welding load and applied input power with the SCR power supply comprising means for generating a first feedback signal proportional to arc current which substantially coincides in time and phase with the arc current; means for generating a second feedback signal proportional to arc current which is substantially nonresponsive to the arc current fundamental ripple frequency, means for weighing the first and second feedback signals in a predetermined proportion to establish an error feedback control signal and means for applying trigger signals to the SCR rectifier network in timed synchronism with the input AC power line as a function of the error feedback control signal.

Abstract: A high voltage power supply used to transfer three-phase a.c. energy to d.c. at full rated power over a large range of output voltages. The electric and magnetic circuits are arranged according to the core type of construction wherein three legs of the iron core extend axially and have the primary coil wound along their full length. The core legs are joined for magnetic circuit continuity at the extremities. A plurality of high voltage decks each having three secondary winding modules mounted and interconnected are stacked axially over the axially extending iron core pieces. The secondary coils on each high voltage deck are interconnected in several three-phase connections, to produce a phase shift in the ripple of the d.c. output voltage of the various decks. A high voltage bridge rectification circuit mounted on each deck produces full wave rectification of the ouptut.

Abstract: To permit ball-bonding of wires of aluminium or aluminium alloy to small electrical circuits or components, a spark discharge is created between the end of the wire and an electrode in a shielding atmosphere with a peak current density in the wire section which is from 40 to 450 times that used for ball-bonding gold wire. In this way oxidation of the ball is prevented.

Abstract: Sudden changes in arc current are slowed to mitigate the resulting noise. A sensor detects large decreases in current during initial stages of arc quench and actuate circuits to maintain ionization and current flow to avoid sharp final drop that causes loud noise impulse. Ionization can be maintained by supplying RF energy at appropriate frequency to the arc electrodes and/or by increasing the arc voltage. The sophisticated control algorithm is implemented utilizing an inexpensive microprocessor to exert proper control of arc sustaining parameters to mitigate arc quenching impulse noise.

Abstract: The power (performance) of an electric arc welder is controlled in dependence upon the changes in the level of the pool of weldment with respect to the level of the adjoining surfaces of the workpiece. The level of the pool of weldment is detected by measuring the arc voltage and, in accordance with the invention, the distance between the end of the fusible electrode and the level of the workpiece upper surfaces adjoining the pool is maintained constant.

Abstract: Power delivered to the welding arc from a constant current rapid response power supply is controllable to maximize arc stability particularly in out-of-position welding operations. A first control modulates the output current from the power supply between a high value close to the maximum output value and a minimum value just sufficient to maintain the welding arc. The modulation is effected at a given frequency appropriately adjusted in accordance with the electrode material and diameter to maintain optimum spray metal transfer in the welding arc. A further control is effected by pulse width modulating the output from the power supply in accord with a set-in current programmed signal which is compared with a current feedback signal or, alternatively, a set in voltage programmed signal which is compared with a voltage feedback signal. This latter control provides for operation of the power supply in a constant current control mode or alternatively, a constant voltage control mode.

Abstract: A gas-shielded, metal-arc, pulse welding process which comprises establishing an arc with a consumable metal electrode in a gas-shielded environment. A direct current in the range of from about 15 to 80 amps is applied to the electrode and pulsated at a frequency of from about 5000 to 25,000 pulses per second to a first maximum amplitude of from 100 to 125% of the minimum current required to produce a spray transfer of metal from the electrode. The pulsating current applied to the electrode is cyclically increased at a frequency of from about 90 to 400 cycles per second to a second maximum amplitude of from about 150 to 600% of the minimum current required to produce a spray transfer of metal from the electrode and is maintained at the second maximum amplitude for a time within the range of from 5 to 50% of each cycle. The process is particularly applicable to automatic welding processes wherein the weld must be accomplished out-of-position.

Abstract: A method of and apparatus for arc welding, in which an energy source supplies the welding process and a simulated process in a bridge circuit the output of which, via an amplifier and a discriminator circuit controls the operation of the source in one of two or more modes having different characteristics such as constant voltage or constant power.

Abstract: A high frequency arc welding apparatus is provided with one D.C. electrical source used for welding purpose and the other D.C. electrical source used for regeneration purpose. One variable impedance element is connected in circuit with the one D.C. electrical source and the other variable impedance element is connected in circuit with the other D.C. electrical source. Electrical energy stored by means of the one variable impedance element temporarily in one inductance provided inevitably in circuit with the one D.C. electrical source is regenerated in the other D.C. electrical source and is discharged in the other inductance provided in circuit with the other D.C. electrical source, by means of the other variable impedance element to be regenerated in the one D.C. electrical source.

Abstract: A method and apparatus for controlling the welding current in shortcircuit transfer arc welding including a method and control apparatus for maintaining the effective value of the welding current during arcing period at a predetermined value. Maintenance of the effective value of welding current during arcing period is necessary to keep the size of a fusion zone and the depth of penetration constant throughout welding operation.

Abstract: There is provided a method and apparatus for electric-arc welding, in which an alternating current of positive and negative pulses is supplied to produce an electric arc between a welding electrode and a workpiece. The ratio of the durations of the positive and negative pulses of welding current is arranged to be changed in response to a signal from a sensing device adapted to sense a change in a characteristic of the electric arc so as to provide optimum welding current for changed welding conditions. The ratio of the amplitudes of the positive and negative pulses may also be varied in response to a signal from a sensing means.

Abstract: A device for plasma-MIG welding comprising a welding torch provided with a non-consumable electrode and a supply of a welding wire, the non-consumable electrode being connected to a first power supply source having a drooping voltage characteristic and the welding wire being connected to a second power supply source having a constant voltage characteristic, the first power supply source being connected in series with the second power supply source, thereby improving the stability of the plasma arc.

Abstract: In short circuit arc welding there are many parameters which influence the automatically controlled welding procedure, but which frequently may affect the quality of the weld. In some circumstances the welding bead which is formed does not flow in to the molten pool of the workpiece, but disintegrates into many small drops around the weld owing to an excessive short-circuit current.The invention proposes methods and arrangements in which certain parameters, such as arc time and a short-circuit current delay time are controlled or maintained constant, so that always a constant bead size is assured owing to a constant power, after which said bead of constant size is first partly introduced into the molten pool and subsequently the short-circuit current for separation is applied.

Abstract: In welding iron, steel, and nonferrous alloys, the wire feed is changed periodically and in synchronism with periodic changes of the electric welding current to establish a previously defined relation between the welding current value and the arc length. The welding current is varied between one producing a spray transfer arc and a current just maintaining the arc.