Abstract: An assembly for welding includes a frame member and a plurality of repositionable torches supported by the frame member adjacent a linear path of travel of a metal strip. The method includes the steps of welding the metal strip, ascertaining the character of the weld and repositioning the torches to alter the character of the weld.

Abstract: The invention relates to a plasma processing reactor for processing a substrate. The plasma processing reactor includes a process chamber. The plasma processing reactor further includes an inductive coil configured to be coupled to a RF power source having a RF frequency wherein the inductive coil generates an electric field inside of the process chamber. The plasma processing reactor additionally includes a magnetic field producing device configured to produce a magnetic field inside the process chamber in proximity of the electric field.

Abstract: The object of this invention is to prevent the occurrence of welding defects such as undercuts, overlaps and faulty angles of fusion, and to increase the efficiency of welding in the horizontal position. Auxiliary wires 5a and 5b are inserted into molten pool 12, and a unidirectional current is made to flow between them. A magnetic field 9 is induced which is approximately orthogonal to the surface of the parent material so as to generate an upward Lorentz force (opposite the pull of gravity) in molten pool 12. This force supports the molten metal and prevents it from dripping, resulting in a better-shaped bead.

Abstract: A wire cleaner having a chamber and containing an arc ring for passing a wire therethrough, such that when the wire and arc ring are provided with opposite electrical potentials, an electric arc discharge occurs from the wire to the arc ring which carries off impurities from the surface of the wire. An inert gas is used to purge the chamber to prevent oxidation of the wire during and following the discharge from the wire. A pair of annular permanent magnets are positioned around the wire on each side of the arc ring to produce a magnetic field parallel to the wire which interacts with the electrical arc discharge and causes the arc to rotate around the circumferences of the wire and arc ring, thereby cleaning the entire wire. A second embodiment is provided in which the pair of permanent annular magnets is replaced by a variable strength electromagnet surrounding the arc ring and wire path. Other embodiments employ a pair of arc rings to carry the electric current so that two arcs are created in tandem.

Abstract: A wire cleaner having a chamber and containing an arc ring for passing a wire therethrough, such that when the wire and arc ring are provided with opposite electrical potentials, an electric arc discharge occurs from the wire to the arc ring which carries off impurities from the surface of the wire. An inert gas is used to purge the chamber to prevent oxidation of the wire during and following the discharge from the wire. A pair of annular permanent magnets are positioned around the wire on each side of the arc ring to produce a magnetic field parallel to the wire which interacts with the electrical arc discharge and causes the arc to rotate around the circumferences of the wire and arc ring, thereby cleaning the entire wire. A second embodiment is provided in which the pair of permanent annular magnets is replaced by a variable strength electromagnet surrounding the arc ring and wire path.

Abstract: The object of this invention is to prevent a defect which occurs in overhead or vertical welding when gravity causes molten metal to drip downward so that the top of the gap has an undercut and the bead has a bulge along the weld line (i.e., a convex bead is created). During overhead or vertical welding, a unidirectional current is made to flow in the molten pool in the direction of the weld line. When the aforesaid current flows in conjunction with a magnetic field, a Lorentz force is exerted in the molten pool in an upward direction towards the upper top side of the groove. This prevents the molten metal from dripping downward and improves the shape of the bead.

Abstract: This disclosure relates to a stabilized plasma injector device specifically adapted to incubate, shape and develop plasma under the influence of an adjustable electromagnetic field to provide ignition and further promote energy coupling between the plasma and a combustible mass. The device includes a pair of shaped coils one of which is evaporated to form the plasma and the other coil provides the electromagnetic force field to influence the characteristic arc symmetry and the energy coupling between the plasma and the surrounding combustible mass.

Abstract: The Plasma-Gun Voltage-Generator (PVG) uses a pulsed plasma-flow to displace magnetic flux, thereby inducing high voltages across multi-turn coils. Typical operating parameters are voltages of 0.5 to 1 MV, pulsetimes in the microsecond regime and output impedances in the few Ohm range. The use of capacitor-bank sources to drive the plasma-gun discharge permits repetitive operation of the PVG at rates of several kHz. The PVG includes 1) a coaxial plasma-gun that serves as a source high speed, electrically-conducting plasma; 2) a source of axial magnetic field; and 3) a multi-turn coil or set of multi-turn coils that will experience an induced voltage when plasma flow displaces magnetic flux from the region interior to the coil(s). The magnetic flux source and the multi-turn coil(s) are placed near the end of the coaxial gun to receive the high speed plasma flow. The coaxial plasma-gun provides an axisymmetric discharge between coaxial electrodes.

Abstract: A plasma generation system includes one or more pairs of electrode units. Each electrode unit emits a plasma carrying gas along a respective axis. Each pair of electrode units is connected to an electric power supply that creates an electric discharge through the gas jets emitted by the two units. The axes of the two units define a "basic" plane. Each unit is associated with a magnetic circuit having two poles on the opposite sides of the basic plane. Each of these circuits is used to move the plasma gas jet emitted by the respective unit towards or away from the plasma jet emitted by the other unit of the pair of units. Therefore, these circuits control the angle at which the plasma jets meet. In addition, for each pair of the electrode units, a three-pole magnetic circuit is provided to move the plasma jets perpendicularly to the basic plane. The three poles of the magnetic circuit extend substantially along the basic plane.

Abstract: The invention relates to a linear microwave source for the treatment of surfaces comprising:a tight enclosure (1),means (B.sub.1, B.sub.2 ; A.sub.1, A.sub.2) for producing a magnetic field in the enclosure and for generating a plasma layer (P),coupling means between the microwave emission means and the enclosure (1),at least one target (2),pumping means (3),gas injection means (9) for checking the ion species of the plasma layer (P).Particular application to plasma surface treatment.

Abstract: The present invention concerns a plasma torch with an integrated independent electromagnetic coil for moving the arc foot. The torch includes a bare torch portion housing a single upstream electrode or a pair of coaxial upstream and downstream electrodes. The electrodes are tubular and are cooled by an appropriate cooling circuit. An injection mechanism injects plasma gas downstream of the upstream electrode or between the upstream electrode and the downstream electrode. A starter mechanism ensures starting of the torch. A field coil moves the arc foot. The field coil has a generally cylindrical shape and is formed of a set of three supports made of an electrically non-conducting material with the shape of coaxial cylindrical tubes connected at one extremity of the unit to a crown provided with an electric connection mechanism. The electric connection mechanism is connected to at least one helical winding provided on at least one of the faces of one of the three cylindrical supports.

Abstract: DC arc plasma torch, in particular intended for obtaining a chemical substance from a plasma-generating gas (P) which includes said substance.According to the invention:the electrode (2A) is in communication with the chamber (3) for injecting the plasma-generating gas via a tubular piece (2B) through which the arc (10) passes and which constitutes the reaction chamber in which said plasma-generating gas (P) gives rise to the plasma (13) under the action of the electric arc (10); andmeans (7, 8) are provided which make it possible to form a fluid barrier (14) between the electrode (2A) and the plasma (13).

Abstract: A method and apparatus for graining a surface having a substantial area traveling at a substantial rate of speed. The method includes directing the surface past an array of electrical arcs traveling about a plurality of loop electrodes arranged to provide overlapping arc loop paths as the surface travels past the array of arc loops. The arc loops are established between the loop electrodes and the traveling surface, and thus contact the surface to grain the same. When each arc is struck between its loop electrodes and traveling surface, it is magnetically impelled about the loop of its electrode by a magnetic field established perpendicular of the direction of arc current flow. An annular sheath of gas is provided on each side of the electrode loop and the arc struck between the electrode loop and the traveling surface.

Abstract: It is known that improved coating properties can be obtained by plasma action in vacuum deposition, especially by vaporization. Substantially higher coating rates can be attained in vapor deposition, but, with high plasma densities, they result in excessive scattering of the electron beam and reduce the power density. According to the invention, a plasma source, preferably a hollow cathode are source, is arranged in the immediate vicinity of the substrate. Between the evaporator and the substrate there is a device for generating a magnetic field so that the region of high plasma density is separated from the evaporator and the electron beam by the magnetic field. The boundary field lines of this magnetic field run along an arc curving with respect to the substrate.

Abstract: The present invention is directed to a high current density glow discharge switch which is capable of preventing confinement of an electron current to the vicinity of the center of a flat electrode during the operation of the switch to prevent an increase in the temperature of the flat electrode and thereby provide a highly reliable and stable switch having a long lifetime. A cathode and an anode each include a flat electrode having a central hole and a cup-shaped electrode electrically connected to the flat electrode. The cathode and the anode are disposed such that the flat electrodes face each other. A cylindrical insulator is disposed on the outside of the cathode and the anode. A coil for generating a magnetic field is disposed on the outside of the cylindrical insulator. Hydrogen gas is sealed in a sealed space defined by the cylindrical insulator, the cathode and the anode.

Abstract: Apparatus for electric arc graining the surface of a traveling electrically conductive workpiece, the surface having a substantial area. The graining is effected by a continuous loop electrode having an elongated main body portion and an elongated continuous loop tip edge projecting laterally from a general plane of the main body portion for establishing an arc between the tip edge and the workpiece surface. The arc is moved about the continuous electrode tip by elongated magnetic means located in close proximity to the electrode, the magnetic means including a continuous loop pole member spaced outwardly of and concentric with the continuous loop tip edge. A second pole member of a polarity opposite the outer pole member is located in the general center of the closed loop tip edge.

Abstract: A plasma torch includes an arc having a generator for producing an axial field in the arc's area of operation in which one or more bodies of ferromagnetic material are placed along the torches central axis; the body is in the form of an element incorporated in the torch and is cooled by the provision of channels for a cooling medium wherein the ferromagnetic body is located near the arc's area of operation to reinforce the magnetic field with the body being moveable in an axial direction to adjust the operation parameters of the arc.

Abstract: Substantial surface areas can be treated by continuously magnetically moving an electric arc around a general loop direction such as a circle, ellipse or oval and moving the surface so that the arc treats a substantial surface area. The arc treatment can be used to clean or increase surface area, or both, and a reactant or treatment agent can be brought to the arc contact site to alter the surface treated with the arc. Auxiliary treatments for the surface can precede or follow the arc treatment, or both. The invention produces very desirable surface properties including a mild roughness or matte condition suitable even for critical applications such as aluminum lithoplate. Other surface characteristics can include one or more of: capillarity, adhesion, emissivity, stable oxide, paintability, and others.

Abstract: An essentially flat "arc-grained" surface of a sheet of aluminum alloy is produced with a coarse and non-uniform microstructure which, after it is coated with a durable phosphate-free coating, provides excellent lithoplate. Though such arc-grained microstructure is much coarser than an electrochemically etched surface typically used on lithoplate, the very coarse surface is peculiarly well-adapted to provide durable lithoplate after it is coated with a phosphate-free protective surface. After the coated surface is coated with a photoresist the excellent resolution of prints is maintained over a large number of repeated uses in an off-set printing press.

Abstract: A welding comprises placing the end of a stud supported by a welding gun on a welding portion of a workpiece, producing an arc discharge across the stud and the workpiece, melting the end of the stud and a portion of the workpiece and bringing the end of the stud so as to abut on the melted portion of the workpiece. A hollow cylindrical member 21 is prepared so that the material has a larger inside diameter than an end 20 of a stud 19 and is made of a magnetic permeable material is prepared. During the arc discharge, the cylindrical member 21 is placed so that the hollow portion is positioned on the side of the workpiece opposite to the stud and corresponding to the end of the stud.

Abstract: The plasma torch (10; 11, 12, 14) comprises an electrical power supply (20) with an arc circuit (21) and a coil circuit (22) which are mounted in series and with means (30) for controlling the level of the current flowing in the coil (22) consisting, inter alia, mounted in parallel with this coil (14), of a chopper consisting of a battery of capacitors (31) and of at least one electronic power switch (32) which may be placed distant from the coil. The electronic switch is preferably of the thyristor diode (321, 322) type, with a resonant turn-off circuit (31, 323).A variant of this chopper uses at least one electronic switch of the GTO thyristor type, controllable in triggering and in switching off, or at least one conventional thyristor equipped with an auxiliary extinction circuit.Application to high-power torches, for industrial, for example metallurgical, use.

Abstract: The plasma torch (10; 11, 12, 14) comprises an electrical power supply (20) with an arc circuit (21) and a coil circuit (22) which are mounted in series and with means (30) for controlling the level of the current flowing in the coil (22) consisting, inter alia, mounted in parallel with this coil (14), of a chopper consisting of a battery of capacitors (31) and of at least one electronic power switch (32) which may be placed distant from the coil. The electronic switch is preferably of the thyristor diode (321, 322) type, with a resonant turn-off circuit (31, 323).A variant of this chopper uses at least one electronic switch of the GTO thyristor type, controllable in triggering and in switching off, or at least one conventional thyristor equipped with an auxiliary extinction circuit.Application to high-power torches, for industrial, for example metallurgical, use.

Abstract: A method for plasma heating of levitated samples for containerless microgravity processing is disclosed. A sample is levitated by electrostatic, electromagnetic, aerodynamic, or acoustic systems, as is appropriate for the physical properties of the particular sample. The sample is heated by a plasma torch at atmospheric pressure. A ground plate is provided to help direct the plasma towards the sample. In addition, Helmholtz coils are provided to produce a magnetic field that can be used to spiral the plasma around the sample. The plasma heating system is oriented such that it does not interfere with the levitation system.

Abstract: The invention concerns a process and a device for surface heat treatment of rod-shaped, longitudinally extended materials with metal surfaces by means of an arc, which rotates and is magnetically driven around the axis of the billet, wherein the arc moves between an annular electrode (anode) and the billet serving as cathode that runs through it.According to the invention, the problem of developing improved measures for stabilizing an arc, inter alia, is solved by rotating the arc by a direct current magnet arranged behind the annular electrode in the direction in which the billet runs and at the same time the magnetic field induced by the direct current magnetic counteracts the pulling effect on the arc base point by the moved billet and the annular electrode current is divided into two divided currents.The field of application is primarily surface heat-treating of rod-shaped, longitudinally extended materials with metal surfaces.

Abstract: A system for negating remnant magnetic fields in a weld joint between two workpieces includes a controller and an electromagnet with two feet that form the pole pieces. The electromagnet feet are formed with surfaces that provide a substantial area for magnetic flux coupling with each workpiece on either side of the weld joint. Inside and outside surface pairs on the electromagnet feet permit effective placement of the electromagnet on the outside or inside of right angle corners formed by two workpieces to be welded. The electromagnet feet may be rotatively connected to the core to accommodate various workpiece configurations. The controller includes an autotransformer and two separate manually operable current controls.

Abstract: In a heat-plasma-jet, an arc is initially generated between opposed endless ends of a pair of electrodes and is moved along the opposed endless ends of the electrodes by generating magnetic fields having the same polarity at the opposed ends of the electrodes. Thereafter, a plasma generating gas is supplied into a region in which the arc is generated.

Abstract: The present invention relates to a method of machining plate materials with a plasma cutter and plasma torch. This method is one in which the density of a magnetic flux formed in the range between the vicinity of the surface of an electrode material 3 fixed to the front end of the electrode and the vicinity of the nozzle opening 1b of a nozzle 1 is between 10 and 200 gauss. The magnetic flux is generated by a magnetization apparatus 4 disposed in the vicinity of the electrode 2 of a plasma torch 100. A workpiece 26 is cut by a plasma arc emitted from a nozzle, the diameter d of which is 1.5 mm or less. The plasma torch 100 for use in this method is equipped with a magnetization apparatus 4 in the vicinity of the electrode 2 and the nozzle diameter d is 1.5 mm or less. The above magnetization apparatus 4 is disposed on the same axis as the axis center of the nozzle opening 1b.

Abstract: A cathode structure of a transition type plasma arc torch, in which a cooling effect is enhanced, and also an amount of consumption of cathode material is reduced by continuously moving a discharge point in the bottom end surface of the cathode during generating of a plasma arc. The cathode structure includes one cathode (21) of small-diameter circular column shape having a minute concave surface portion formed on its bottom end surface symmetrically with respect to its axis, a holder (20) for holding the cathode having such structure that easy and highly effective cooling is possible, and a generating device of lines of magnetic force (23) disposed coaxially with the aforementioned cathode (21) so that a line of magnetic force vector B such that E.times.B.noteq.0 may be fulfilled with respect to a line of electric force vector E generated on the bottom end surface of the cathode, may be generated symmetrically with respect to the axis of the cathode.

Abstract: A plasma torch includes two axially spaced tubular electrodes and an electromagnetic coil for rotating an electric arc formed between the electrodes. Each electrode is held in a support, at least one support containing a cylindrical cooling chamber through which an electrically nonconductive cooling fluid can be passed. The electromagnetic coil divides the cooling chamber into two annular spaces which are interconnected at one end.

Abstract: A method for pressure welding of parts with heating with an arc moving in magnetic field in which the parts (2,3) are placed coaxially with each other with a working gap (.delta.) between their ends magnetic field is created in the gap (67 ) and electric arc (6) is fired to heat the ends of the parts (2,3). A d-c component of voltage of the arc (6) is measured, and when this component reaches its minimum value corresponding to a temperature of the ends of the parts (2,3) at which plastic deformation of the material of the parts can occur, a pulsed increase in the arc current is carried out, with subsequent upsetting of the parts (2,3).

Abstract: The surface of a metal workpiece is remelted by a heat producing energy beam so as to form a molten metal layer thereon. While remelting the surface, a magnetic field is generated coaxially with the energy beam and is applied across the molten metal layer so as to cause the heat energy to flare and, thereby, produce a Lorentz force in the molten metal layer. By the Lorentz force, the molten metal is agitated. The heat energy and magnetic field are oscillated, or reciprocally moved, relative to the surface so as to cause a flow of the molten metal from the edges of the molten metal layer toward the center, thereby providing a uniform chilled layer thickness.

Abstract: A plasma-arc cutting apparatus having a plasma torch producing a plasma arc and cutting a workpiece with the plasma arc, the plasma torch including a nozzle from whcih the plasma arc is ejected toward the workpiece; a feed device moving the plasma torch relative to the workpiece; a magnetic-field forming device producing a magnetic filed, and applying the magnetic field to the plasma arc so as to intersect the plasma arc and thereby deflect the arc; a first control device numerically controlling the feed device according to cutting operation information, the cutting operation information including cutting path data representative of a predetermined curved cutting path along which the plasma torch is moved over the workpiece, the first control means providing torch position data representative of a current position of the plasma torch relative to the workpiece; and a second control device controlling the magnetic-field forming device according to the cutting operation information and the torch position data so

Abstract: The machine incorporates two clamping means, a static one fitted to a bedframe and a movable one mounted on rods which are attached to upsetting hydraulic cylinders with their ends with provision for reciprocating back and forth. Each clamping means consists of a base and a holding-down plate which is hinged to the base and displaced by a hydraulic cylinder a body of which is hinged to the base and a piston rod of which is hinged to the holding-down plate interacting with a holding down roller in clamping workpieces. The machine is provided with a fastener in the form of an inverted L-shaped lever, a means of adjusting the alignment of the workpieces for welding, and a means of setting a gap between the workpieces, made as a plunger and an adjustable stop installed coaxially.

Abstract: A method and apparatus for increasing radiant heat production of hydrocarbon fuel combustion systems are provided. In one aspect, the apparatus includes a pair of spaced electrodes through which a hydrocarbon fuel gas is flowed. An electrica arc is struck across the electrode gap to pyrolyze a portion of the hydrocarbon fuel gas, leading to the formation of carbonaceous heat radiative bodies which are entrained in the hydrocarbon fuel gas stream. In the presence of an oxidant gas such as air, a turbulent diffusion flame is created having an increased luminous radiant heat output, an improved turn-down ratio, increased flame stability, and reduced nitric oxide emissions. The method and apparatus are particularly adapted to increasing the luminous radiant output of hydrocarbon fuels having a low carbon-to-hydrogen ratio such as natural gas.

Abstract: A method of welding metals wherein the size and shape of a weld pool as w as the traversing of the arc from one metal to the other is commanded magnetically by predetermined data, which data is updated by observing and characterizing isotherms in the weld pool, comparing the observed isotherms with a predetermined set of desired isotherms and then updating the command data for optimum performance.

Abstract: A method and apparatus for welding a tube to a tube plate such as in a vehicular radiator core are provided wherein a tube end formed by a tube end sidewall protrudes through an aperture in the plate to provide a joint for welding the sidewall to the plate in the region of the aperture. A welding arc is moved in a selected direction along a path of travel to form a weldment along the joint where the arc encounters the joint, while simultaneously reciprocating the arc back and forth in a crossways direction relative to the selected direction with an amplitude of reciprocation sufficient to encounter at least a portion of the joint lying to at least one side of the path to further form a weldment along the joint portion as the arc moves in the selected direction.

Abstract: A transferred arc torch is comprised of a first electrode surrounded by a coil. A second electrode is positioned adjacent to the first electrode so as to provide a small gap therebetween for striking an arc. The second electrode is configured to enable the arc to be transferred therefrom. The transferred arc torch may be used in conjunction with a vessel to provide a unique plasma reactor.

Abstract: The invention concerns plasma torches comprising an upstream electrode (12), a downstream electrode (11), a chamber (15) for the injection of plasma producing gas, a priming electrode (13) and optionally a magnetic field coil (14), in which the upstream root of the arc is displaced on the upstream electrode. According to the invention, in order to control a continuous or reciprocating and/or an oscillatory translation, the field coil is supplied with a variable direct current, if need be a pulsatory undulatory current, and/or a diffuser is placed at the inner end of the upstream electrode which is supplied with a modulated flow of gas which it causes to whirl. Application in high power plasma torches for regularizing and rendering uniform the wear of the electrodes so as to prolong the life thereof.

Abstract: A hub assembly comprising a hub member (10), a flange (4) for wheel attachment, a double row bearing (2), and a constant velocity ratio universal joint (3), wherein the bearing has at least one inner bearing ring (13, 14) which is a separate component received on the hub member, and a connection between the hub member and a further part of the assembly is established by a welding and upsetting operation, and the inner bearing ring is engaged to hold it in position and to set the bearing as a result of such welding and upsetting operation. The welded and upset connection may be provided between the hub member and an outer member (15) of the constant velocity ratio universal joint, or between the hub member and flange. A weld bead formed by the welding and upsetting operation may engage the inner bearing ring either directly or indirectly, or a projection extending from the part welded to the hub member may engage the inner bearing ring.

Abstract: An apparatus for surface treatment, especially for etching and/or coating workpieces by ion bombardment is described. This apparatus comprises at least one ionization chamber having at least one hot cathode, gas atoms being introduced into this chamber for the low-voltage arc-discharge between the ionization chamber and at least one anode inside the treatment chamber connected to a vacuum pump. At least one magnet coil mounted within the treatment chamber is used to control the ion density of the low-voltage arc-discharge and is mounted inside the treament chamber. The workpieces to be treated are arranged outside these magnet coils. Homogeneous surface treatment of the workpieces is ensured by the selected arrangement of magnet coils and workpieces.

Abstract: Apparatus for reducing the strength of magnetic fields in a vicinity of weld zone in a workpiece to be welded includes a Hall effect sensor for sensing the strength of the resultant magnetic field in the weld zone vicinity, and a magnetic field generator responsive to the output signals from the Hall effect sensor to generate a counterbalancing magnetic field in the weld zone vicinity so as to reduce the resultant magnetic field in the weld zone vicinity.

Abstract: The invention relates to a device for welding of metallic parts with tubular cross section with an electric arc, having at least two magnets with the same polarity, surrounding the weld seam line annularly with their pole faces. In such a welding device, the pole faces are easily contaminated with weld splashes, during welding. Such contamination has a negative influence on the electric arc path and the weld seam line is deteriorated. In order to avoid such contamination, the invention proposes that the pole faces (4) be provided each with a covering protection ring (5), presenting an inner surface (7) inclined towards the weld seam line.

Abstract: Method and device for controlling the erosion of the electrodes of a plasma torch, in which an electrical arc is produced when the electrodes are connected to an electrical supply. An axial magnetic field generated by a system of field coil causes the rotation of the extremities of the arc according to a circular trajectory inside the electrodes. The relative position of the field coils is such that there exists a position on the electrode surface where the value of the total magnetic field is a minimum where the arc runs thereby controlling the erosion of the electrodes. According to the invention, the value of current is periodically varied in the system of field coil used to cause the rotation of the arc, thereby producing a controlled axial displacement of the circular trajectory of the extremity of the arc.

Abstract: Apparatus and method for evaporation arc stabilization including a target having a surface of material of non-permeable material to be evaporated; circuitry for establishing an arc on the target surface for evaporating the target material, the arc being characterized by the presence of charged particles and a cathode spot which randomly migrates over the target surface; and a confinement ring surrounding the target surface, the ring being composed of a magnetically permeable material to thereby confine the cathode spot to the target surface.

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: A high power non-transferred electric arc heater utilizing interelectrode segments which create a stepped arc chamber intermediate two hollow, substantially cylindrical, axially spaced electrodes. Gas to be heated is admitted upstream of the arc chamber and between adjacent segments. Gas is used to form a cold boundary layer about the expanding core of arc-heater gas. Additional secondary gas inlets adjacent the electrode provide fluid dynamic means for arc positioning on the electrode segments. Gas pressures of less than or in the range of about 1 atmosphere to about 50 atmospheres are used with power levels of about 10 MW being possible. The stepped arc chamber facilitates arc transfer to the downstream electrodes and allows a larger diameter for the arc heated gas while the boundary layer of gas maintaining comparable spacing along the length of the arc-heated gas and the surface of the arc chamber reducing the rate of heat transfer from the arc heated gas to the segments of the arc heater.

Abstract: A large diameter stud and a method and apparatus for welding same are provided. The large diameter stud has a protruding tip at a weldable end thereof containing a solid rod-like body of flux. A ceramic ferrule which can have a two-step cavity surrounds the weldable end portion of the stud when engaged with workpiece to which it is to be welded. An arc blow coil surrounds the ferrule and is spaced therefrom with powdered flux therebetween and above the ferrule. The arc blow coil is attached to adjustable legs of a welding tool and has a weight thereon to aid in supporting the welding tool upright on the workpiece during the welding operation. In the welding cycle, a relatively low weld current is used for the main welding arc and is maintained for an extended period of time. Current through the arc blow coil is initiated when the welding cycle begins and is gradually increased to a maximum at an intermediate point in the welding cycle.

Abstract: An automatic valve seat build-up welding apparatus for a Y-type main steam isolation globe valve used in an atomic power station is disclosed which is characterized in that the valve seat can be build-up welded on the spot by the welding torch introduced into the valve box with the welding operation being carried out remotely from the spot and viewed by an image sensor positioned near the welding torch so that the exposure of an operator to a radioactive environment is prevented.

Abstract: A method for welding by a magnetically driven arc, which comprises placing two objects of welding in butt formation with a small gap between the end edges thereof to form a welding line; parallelly connecting a first electric circuit comprising the two objects of welding and a cable arranged on the surface side of the two objects of welding and a second electric circuit comprising the two objects of welding and another cable arranged on the back side of the two objects of welding to a welding power source; flowing a welding current through the first and second electric circuits to produce an arc in the small gap; moving the arc along the welding line under the effect of an electromagnetic force in the direction of the welding line, the electromagnetic force being produced by the magnetic flux of magnetizing coils provided near the end edges of the two objects of welding and welding current flowing through the arc; and changing the amount of welding current flowing through the first and second electric circuit

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.