Abstract: A resistance spot welding method of squeezing parts to be welded, which are a plurality of overlapping metal sheets, by a pair of electrodes and passing a current while applying an electrode force to join the parts to be welded comprises: a first step of passing a current by constant current control to form a fusion zone having a diameter of not less than 2?{square root over (t)}, expressed in mm, between the metal sheets, where t, expressed in mm, is a sheet thickness of a thinnest metal sheet of the metal sheets; a second step of cooling the fusion zone to have a diameter of not greater than 80% of D, where D, expressed in mm, is a diameter of the fusion zone formed in the first step; and a third step of performing adaptive control welding by controlling a current passage amount according to a target that is set.

Abstract: A machine for the flash butt welding of rails is provided. The machine comprises electric contacts yokes having controlled drives and further comprise holes through which guide pins are passed.

Abstract: This invention relates to a flash butt welding process for joining sections of a railway line using vibration apparatus, the process including configuring and attaching a vibration apparatus on the railway line such that a vibration means is attachable to the railway line, and controlled vibration of the railway line at a suitable low frequency of vibration and amplitude of vibration, and then welding sections of railway line together using a flash butt welding means, and applying vibration to the sections of railway line until the flash butt weld is complete, and applying a controlled vibration to the welded sections of railway line for a period of time sufficient to allow for heat to dissipate from the weld area, and to allow for the weld area to be stress relieved for an improved weld joint.

Abstract: An electric arc welding wire having an outer cylindrical surface and an electrically conductive layer on the surface wherein the layer comprises an alloy of copper with the copper content being about 60% to about 90% by weight of said alloy. Furthermore, the layer can be made thin with a thickness of less than about 0.50 microns while using essentially pure copper.

Abstract: Exemplary embodiments provide a resistance welding method capable of stabilizing quality or improving efficiency of resistance welding such as spot welding. This resistance welding method comprises a calculating step of calculating resistance ratio X of a second electric resistance value R2 of workpieces to be joined in residual heat after Joule heating stops to a first electric resistance value R1 of the workpieces immediately before the Joule heating stops or vice versa (R2/R1 or R1/R2); a determining step of determining whether the resistance ratio X is equal to or greater than a threshold value Xn, and a reheating step of carrying out the Joule heating again when the resistance ratio X is smaller than the threshold value Xn. Thereby at least part of a welding portion is melted and solidified to reliably form a nugget, and a stably resistance-welded member can be provided.

Abstract: A direct welding process for joining a current collector to a terminal pin in the construction of electrochemical cells is described. The resistance welding process utilizes increased current combined with an applied force to bond dissimilar metals with a melting temperature differential of preferably more than 500° C. Preferably, the method is used to bond the terminal pin to the cathode current collector. This method of attachment is suitable for either primary or secondary cells, particularly those powering implantable biomedical devices.

Abstract: An improved welding head for creating an in-track weld between a first rail segment and a second rail segment includes a controller having computer-readable instructions read by the controller. The computer-readable instructions include instructions for compensating for rail jerk during in-track welding. The welding head includes a closing force actuator, such as a hydraulic cylinder, for moving the rail segments toward one another. A pressure transducer is monitored during welding to determine a closing force. An impending jerk of the rail movement is detected if an abnormal closing force change is observed, and in response the flow of hydraulic fluid into or out of the hydraulic cylinder is restricted to prevent or minimize the jerk. In addition, when an impending jerk is detected the weld current may be temporarily increased to burn or prevent the formation of short circuit paths between the rails.

Abstract: A rail repair insert enables repair of rails and rail-like structures. A rail defect is initially identified and removed as contained within a volumetric material portion so as to form a contoured void while maintaining continuity of the rail opposite the void. A pre-formed insert is then placed into the void thereby effecting a rail-to-insert interface. Current is driven through the interface as force directs the insert against the rail. Resistance heat and pressure weld the insert to the rail. The flash welding aspects remove oxides and other impurities from the interface, and the forge welding aspects create a robust solid state weld. Excess material, whether flash, rail, or insert-based, is removed during the finishing processes to provide a virtually seamless rail repair. The solid state weld repair insert may be used to repair any number of targeted metallic rail-like structures.

Abstract: The present invention provides a method and device for inductively heating a first and second surface to form a closure assembly. A method contemplated by the present invention includes spacing an upper die from a lower die for receipt of the first surface and the second surface configured in an overlying orientation, securing one end of the first surface to an end of the second surface and compressing the first surface toward the second surface to form a compressed arrangement which is inductively heated into a closure assembly.

Abstract: An improved method for executing a flash butt weld to join first and second rail segments includes applying a voltage to the first rail segment and the second rail segment to establish a voltage difference between the first and second rail segments. The rail end faces are brought into contact, resulting in an electrical current between the first rail end face and the second rail end face, resistively heating material at the interface. As material burns off at the interface, the power consumed at the rail end interface as a function of rail displacement is periodically sampled. If the comparison indicates that the power per unit of rail displacement is not increasing from sample to sample, the burn-off process is terminated. In a further aspect, if the power per unit of rail displacement exceeds a predetermined threshold, the burn-off process is terminated.

Abstract: A rail repair method enables repair of rails and rail-like structures. A rail defect is initially identified and removed as contained within a volumetric material portion so as to form a contoured void while maintaining continuity of the rail opposite the void. A pre-formed insert is then placed into the void thereby effecting a rail-to-insert interface. Current is driven through the interface as force directs the insert against the rail. Resistance heat and pressure weld the insert to the rail. The flash welding aspects remove oxides and other impurities from the interface, and the forge welding aspects create a robust solid state weld. Excess material, whether flash, rail, or insert-based, is removed during the finishing processes to provide a virtually seamless rail repair. The solid state weld repair methodology may be used to repair any number of targeted metallic rail-like structures.

Abstract: An improved method for executing a flash butt weld to join first and second rail segments includes applying a voltage to the first rail segment and the second rail segment to establish a voltage difference between the first and second rail segments. The rail end faces are brought into contact, resulting in an electrical current between the first rail end face and the second rail end face, resistively heating material at the interface. As material burns off at the interface, the power consumed at the rail end interface as a function of rail displacement is periodically sampled. If the comparison indicates that the power per unit of rail displacement is not increasing from sample to sample, the burn-off process is terminated. In a further aspect, if the power per unit of rail displacement exceeds a predetermined threshold, the burn-off process is terminated.

Abstract: A method of monitoring and maintaining a weld cap which is executing successive resistance welds on a plurality of workpieces includes measuring a first weld indentation formed during a first resistance weld and measuring a second weld indentation formed during a second resistance weld. The measured first and second weld indentations are compared with a severe threshold. If either of the measured first or second weld indentations is greater than the severe threshold, an abnormal condition is signaled. The method may include tip dressing the weld cap based upon the signaled abnormal condition. The method may further include determining a degradation rate between the first resistance weld and the second resistance weld. The degradation rate is the time differential between the measured first and second weld indentations, and either a first or a second tip dressing schedule is chosen based upon the determined degradation rate.

Abstract: A method of arc welding a first metal piece to a second metal piece includes the steps of extend a welding head between the space between first and second metal pieces, bending a filler wire, passing the bent filler wire through the welding head such that an end of the bent filler wire extends in a direction toward a surface of one of the first and second metal pieces, and arc welding the end portion of the bent filler wire onto the surface of the metal piece. The method further includes rotating the end of the bent filler wire toward another surface of the metal pieces and arc welding the of end of the rotated bent filler wire onto the surface of the another metal piece. The welding head travels along the space between the first and second metal pieces as the step of arc welding occurs.

Abstract: A machine for the flash-butt welding of rails has two tong-type clamping devices, made in the form of two double-arm levers mounted on a common central axle and isolated from one another, hydraulic cylinders of clamping and displacement of parts being welded, two welding transformers built into double-arm levers of one of two tong-type clamping devices, and current-carrying elements which include rods of displacement and upsetting, electric contacts-yokes and flexible jumpers. The electric contacts-yokes have controlled drives and the upper part of each electric contacts-yoke has holes, through which guide pins are passed, and a retaining spring is fixed on a lateral surface of the electric contacts-yoke.

Abstract: A rail repair method and insert therefor enables repair of rails and rail-like structures. A rail defect is initially identified and removed as contained within a volumetric material portion so as to form a contoured void while maintaining continuity of the rail opposite the void. A pre-formed insert is then placed into the void thereby effecting a rail-to-insert interface. Current is driven through the interface as force directs the insert against the rail. Resistance heat and pressure weld the insert to the rail. The flash welding aspects remove oxides and other impurities from the interface, and the forge welding aspects create a robust solid state weld. Excess material, whether flash, rail, or insert-based, is removed during the finishing processes to provide a virtually seamless rail repair. The solid state weld repair insert and underlying methodology enabled thereby may be used to repair any number of targeted metallic rail-like structures.

Abstract: An improved welding head for creating an in-track weld between a first rail segment and a second rail segment includes a controller having computer-readable instructions read by the controller. The computer-readable instructions include instructions for compensating for rail jerk during in-track welding. The welding head includes a closing force actuator, such as a hydraulic cylinder, for moving the rail segments toward one another. A pressure transducer is monitored during welding to determine a closing force. An impending jerk of the rail movement is detected if an abnormal closing force change is observed, and in response the flow of hydraulic fluid into or out of the hydraulic cylinder is restricted to prevent or minimize the jerk. In addition, when an impending jerk is detected the weld current may be temporarily increased to burn or prevent the formation of short circuit paths between the rails.

Abstract: An improved method for executing a flash butt weld to join first and second rail segments includes applying a voltage to the first rail segment and the second rail segment to establish a voltage difference between the first and second rail segments. The rail end faces are brought into contact, resulting in an electrical current between the first rail end face and the second rail end face, resistively heating material at the interface. As material burns off at the interface, the power consumed at the rail end interface as a function of rail displacement is periodically sampled. If the comparison indicates that the power per unit of rail displacement is not increasing from sample to sample, the burn-off process is terminated. In a further aspect, if the power per unit of rail displacement exceeds a predetermined threshold, the burn-off process is terminated.

Abstract: A method for monitoring a resistance welding process carried out on a stack of metal workpieces (1) clamped between two electrodes (2a, 2b) of a clamp (3), and a device therefor. According to the method, the electrodes (2a, 2b) are subjected to a clamping force (F) and a voltage (V(t)) enabling a current (I(t)) to flow through the stack of metal workpieces (1). The monitoring method further includes at least one step of analysing the clamping force (F) by comparison with a model from a prior learning process. The result of the analysis of each step is taken into account by a decision-making matrix to generate a correction and/or control signal intended for the welding process.

Abstract: A welding device for welding together two rails of a track and producing a welded joint is composed of two halves. An air nozzle and a temperature sensor are mounted on one of the halves. Via a cooling opening of the air nozzle, a glowing-cooled hot welded joint can be cooled in a controlled manner, immediately after a welding bead has been sheared off, by supplying compressed air to the joint. Thus, optimal welding of head-hardened rails can be achieved.

Abstract: The invention relates to a welding head (20) having an infeed shaft (2) and an electrode movable via a cylinder (7). Detection of various parameters via a pressure sensor (9) is provided for in this case.

Abstract: A rail welding device arranged for mobility along a track direction for effectuating the electric resistance welding of two track rails, comprising a control unit, and two halves of the device movable in the track direction, each half of the device being aligned with a respective one of the track rails and comprising a pair of clamping jaws pivotal towards and away from each other in a plane extending transversely to the track direction. Hydraulic cylinders move the two halves of the device in the track direction, and further hydraulic cylinders pivot the clamping jaws of each half away from each other between a set-up position in which the rail heads of the track rails may freely pass between the clamping jaws and a welding position in which the clamping jaws engage the rail webs. A sensing device detects the welding position at the end of the pivoting motion of the clamping jaws and sends control signals required to effectuate the electric resistance welding to the control unit.

Abstract: A laser welding method and apparatus includes a laser manipulator that directs a laser beam emitted from a laser generator at various predetermined angles toward predetermined positions within a laser work zone. A transport device passes workpieces through the laser work zone where the laser beam manipulator can direct a laser beam at desired interfacing portions of each workpiece to weld those interfacing portions together. The controller is programmed to cause the manipulator to weld the workpieces without halting their motion through the laser work zone.

Abstract: A method of repairing a damaged railroad rail comprising the steps of: identifying a defect in the rail, removing the portion of the rail having a defect and leaving two truncated rail ends, preparing the truncated rail ends for welding, and welding the two truncated rail ends together.

Abstract: A flash butt rail welding welderhead combines in a single unit, the ability for the three functions of rail pulling, flash butt forging and maintaining the “after forged” displacement without any change in platen position such that shearing may be accomplished in three stages, a single stage, multiple stages or a progressive stage, all while maintaining clamping and stretching force on the rails.

Abstract: A method of flash-butt welding in which the travel speed (Vt) of the machine mobile plate and the welding voltage (U2) are changed (by preset programs) and the travel speed is controlled through negative feedback by welding current, the voltage being changed discretely for each flashing fixed interval of tm duration as a function of the increment of the actual average speed of flashing details of shortening (Va) during the previous flashing interval, Va value being maintained at the present level, lower than Vm. The invention envisages a change of the coefficient of enhancement of the negative feedback in a discrete manner for each preset flashing interval of tm duration as a function of Va increment during the previous flashing interval.

Abstract: A method and apparatus are provided for flash butt weld joining adjacent rail ends on site during initial field installation where at least one of the rails is fastened to the roadbed, and inclosure butt welding rails as in de-stressing long sections of rail track where both rails are fastened to the roadbed. The method and apparatus apply electrical power to the adjacent rail ends while simultaneously effecting relative closing movement between the rails ends through actuating means so as to bring the rail ends into position to effect current flow between the rail ends, and determining a force necessary to move the adjacent ends into a welding position under varying environmental conditions of the rails as the adjacent rail ends close and during flashing of the adjacent rail ends due to the current flow.

Abstract: An improved welding process in which two metallic pieces are each composed of weld compatible parent metal, one metallic piece has one surface and the other metallic piece has another surface each having prominences positioned thereon and an oxide of parent metal disposed on the overlying surfaces and prominences including the steps of applying a force along longitudinal axis of metallic pieces to position the prominences to abut; applying a force transverse to the longitudinal axis of one metallic piece providing relative movement in first and second directions transverse to the longitudinal axes, causing displacement to the cross sections of the metallic pieces, moving one surface transverse relative to other surface and the longitudinal axis; and causing an electrical current to pass through metallic pieces elevating temperatures with electric resistance heating for thermal-fusion welding by the relative movement.

Abstract: A welding method and apparatus for flash butt welding adjacent ends of axially aligned railway rails includes a base frame and fixed and movable platens supported on the base frame. The platens support rail sections and are under the control of controller means operative to automatically move the movable platen through a predetermined distance/velocity relation as electrical power is inputted into the rail ends during straight flashing, preheating, flashing and upsetting phases of a welding cycle. The controller includes PID feedback loops operative to maintain the predetermined platen distance/velocity relation with entry of a single parameter by the operator. Significantly improved quality and repeatability of rail welds are obtained.

Abstract: An apparatus for reducing a gap between an end of a rail section and an adjacent end of a longitudinally succeeding rail section of a rail fastened to ties by fastening elements by tensioning or longitudinally extending the rail section comprises two longitudinally spaced beams extending transversely to the track rails, a pair of clamping members mounted on each transverse beam for pivoting about parallel vertical axes at respective sides of the rail sections of the rail and having cooperating clamping jaws for engaging the rail sections between the clamping members upon pivoting thereof, the pairs of clamping members being longitudinally spaced from each other, hydraulic drives interconnecting the clamping members at each side of the rail sections of the rail, and a rail centering mechanism affixed to each transverse beam in the range of each pair of clamping members, each rail centering mechanism comprising at least two independently operable hydraulic cylinders carrying rams adapted to be pressed against a

Abstract: In a high frequency resistance welding system useable with massive or spatially extensive workpieces, the welding head is transported over weld areas by gantry means to provide high speed, high quality welds at appreciably less cost and with quality comparable to that of welds from conventional stationary head systems.

Abstract: A welding fixture by which two elongate members are manipulated in a manner to become butt welded together. Two gripping members in the form of groups of spaced slip assemblies are enclosed in mounted relationship within a housing. The slips of each group circumferentially extend about a longitudinal axis of the housing, with the slips of each group being radially spaced from the longitudinal axis of the members to be joined. A first group of slips are mounted for movement within a plane which is perpendicular to the longitudinal axis of the members to be joined. The other group of slips are likewise arranged within a plane spaced from and parallel to the first plane. All of the slips are moved with great force towards the longitudinal axis of the members to be joined. The fixture includes means by which the members are moved toward one another with great force. Each group of slips further include an electrical contact which provides a source of current to each of the members to be joined.

Abstract: A rail alignment device and a shear head are suspended from a trolley running over a rail welding machine. The alignment device comprises structure forming a downwardly-opening bight and carrying locating stops, clamping cylinders and transducers with sensing plungers all of which project into the bight. The rail ends to be butt-welded are received within the bight for alignment. One of the rails is clamped against the stops by the cylinders. The location of the other rail relative to the structure is sensed by the transducers and the machine clamps are adjusted until those transducers indicate alignment of the rails. The device is then removed and stored remote from the gap, with the shear head, during welding. The shear head comprises a horseshoe-shaped back plate which carries three cutting tools. An arm, which is pivotally mounted on one of the ends of the back plate and adapted to be latched to the other end to close the bight of the back plate, carries a fourth cutting tool.

Abstract: An apparatus for welding two profile or section rods by means of electrical resistance welding, especially an apparatus for welding two rails. There is provided for each of the profile or section rods a clamping device having contact electrodes for infeeding the welding current. Both of the clamping devices are displaceable relative to one another in the direction of the profile or section rods, in order to exert a pressure force at the weld joint. To prevent distortion or displacement of the end regions of the profile sections directly neighboring the weld joint, a centering device is arranged between both of the clamping devices. This centering device can be brought into engagement with the end section of both the one as well as the other profile rod and fixedly retains such end sections. The centering device can comprise two similarly constructed pivotal arms rotatable about a common centering shaft.