Showing papers on "Electric resistance welding published in 1971"

Apparatus for controlling electric welding processes

Abstract: An apparatus for controlling electric welding processes with consumable electrodes by generating electric pulses of the variation in the welding parameters, the voltage, current or mechanical vibration, in the workpiece. These variations which are characteristic for the melting during welding are picked up, transformed and supplied to a signaling device to furnish a statement on the transfer of the material which the welder uses to correctly guide the electrode.

Apparatus for vacuum welding of plastics envelopes

Abstract: The specification discloses vacuum packaging apparatus including welding bars, and clamping bars for holding the edges of the packaging envelope before, during, and after the welding operation Preferably the clamping bars may have grooves therein to facilitate escape of air from within the envelope during the evacuation phase A jet of air is blown across the welded edge to cool the weld and facilitate separation of the welded edges from the welding bars

Combination welding torch

Abstract: A combination welding torch. Adapter means are provided for electric arc welding utilizing a consumable electrode interchangeable with elements for inert gas shielded arc welding utilizing a non-consumable electrode, and connection means are provided for use in the welding torch apparatus, to thereby provide a unitary welding torch usable interchangeably for performance of welding operations.

Method for the ultrasonic welding of wires on the metal surface of a support

Abstract: A method of and a device for the ultrasonic welding of wires comprising a non-metal insulating layer on the metal surface of a support by means of a welding tip which is made to vibrate in a direction parallel to the longitudinal direction of a wire to be welded; according to a previously programmed welding cycle, the insulating layer is first removed locally and the wire is then welded; a preceding mechanical or chemical cleaning of the wires is not necessary. The method according to the disclosure provides a welded joint which has compact dimensions and a high mechanical strength.

Automatic arc welding machines

Abstract: Device for performing completely automatic welding operations using fusible or infusible electrode, in accordance with a program directly governed by the path of the electrode, by emission of electric signals corresponding to equal elementary portions of path, such signals being collected by at least one step-by-step motor actuating the programmer. The device is characterized by the fact that the programmer includes means of controlling and adjusting all the welding parameters listed below : welding current strength, current pulsations, wire advance, wire advance pulsations, starting and stopping the unwinding of the wire, the rate of movement of the electrode, variations in such rate, arc fading, the minimum flow of protective gas, adjustment of the position of a torch perpendicularly to the welding wire and parallel to the surfaces to be welded, adjustment of the distance of the torch from the surfaces to be welded, slope of the torch in a plane passing through the welding wire, and slope of the torch in a plane perpendicular to the welding wire. The programmer turns step-by-step under the impulse of the electric signals emitted by the means of moving the torch, so that the angular speed of the programmer is directly proportional to the path travelled by the torch.

Method of and apparatus for welding an end plug onto a nuclear fuel element

Abstract: Welding methods and apparatus for bonding a metallic end plug into an end of a metallic fuel tube or rod for a nuclear reactor. Defects in the weld joint between the fuel tube and end plug are substantially reduced by arc welding in a chamber filled with an inert gas, disposing the welding electrode directly over the joint to be welded, deflecting plasma produced during the welding away from the body of the fuel tube, and directing the plasma into the joint.

Self-adaptive welding torch controller

Abstract: A fully automatic, self-adaptive welding system has been provided for programmed welding applications. The welding torch position, either vertically or horizontally, is generally responsive to a signal proportional to the work-to-torch spacing as well as certain other signals including pulses used to control the oscillation of the torch across the weld area. Control of the torch oscillation is, in part, supplied by the spacing signal. Use of the system ensures welds of high quality as to weld tie-in, conformity to vertical or horizontal irregularities in the parts, and thickness.

Electrical system for automatic arc welding

Abstract: A process and system for welding of the tungsten inert gas (TIG) type is described. A welding torch is mounted on a mechanism which provides for motion of the torch with respect to the work (a pipe being welded) in three different directions. Movement in each direction is electronically controlled so as to obtain preset magnitudes of oscillation of the torch, both vertically and laterally with respect to the work. The vertical oscillation is provided by following the pulsating arc current in accordance with a preselected control function. In addition, the system and process provides for control of substantially all of the parameters affecting the formation of the weld in order to produce improved weldments.

Explosion-bonded metals for marine structural applications

Abstract: The application of explosion-bonded aluminum-to-steel welding transition joints on marine vessels is discussed. Evaluation of this material's suitability for joining aluminum superstructures to steel decks is reviewed in detail. Galvanic corrosion is demonstrated to be negligible, thereby providing significant savings on maintenance costs when compared to mechanical connections. It is shown that mechanical properties, design adaptability, and installation costs meet marine-industry requirements.

Control apparatus for short-circuit arc welding

Abstract: An apparatus for controlling the feeding of the welding electrode in short circuit metal transfer arc welding which employs a feeding speed detecting circuit. The feeding speed varies according to variations in the period of shortcircuiting between the electrode and the workpiece and the time during which a welding arc is generated.

Resistance welding electrode

Abstract: A spot welding electrode composed of a low resistivity copper alloy has a peripheral slot near the tip to concentrate current flow in the central portion of the electrode. The slot contains a high resistivity steel support material to lend strength to the electrode.

Apparatus for plasma welding

Abstract: Plasma welding of light-metal workpieces and materials subject to oxidation is carried out using square-wave alternating current. The energization circuit comprises a bridge of controllable rectifier-type elements, the welding electrode network being positioned in a diagonal of the bridge while a direct-current source with a declining characteristic is connected across the other diagonal.

Nut welding electrode

Abstract: A resistance welding electrode for welding nuts or other items which have apertures to parts provided with corresponding apertures, consisting of a main water-cooled body upon which os located an adaptable welding face and containing a sliding pilot pin which passes through and extend beyond the welding face. The nut or the like to be welded is palaced upon the pilot pin, and the part to which it is to be welded is located on the welding face. To weld, the pilot pin is depressed so that the nut is pressed against the part to which it is to be welded. The base of the pilot pin is equipped with a piston which slides within a compression chamber within the main body, so that when the weld is completed and the pressure on the pilot pin is released, the compressed air in the said chamber returns the pin to its normal position.

Resistance welding of sheet metal covered with non-metallic layers

Abstract: A machine for the spot or roller seam-welding of sheet metal pieces covered with layers of non-metallic material by removing the layer from the zones to be welded and subsequently applying a rust-protective layer over the welding zone, an upright structure, a transport track for the sheet metal pieces mounted therein, an upper and a lower rail arranged transversely of said track vertically movable on said structure, a series of milling machines attached to the rails, and a lever mechanism pressing said milling machines on sheet metal pieces lying on the transport track.

An Investigation Into the Factors Contributing to Welding of Contact Electrodes in High Vaccum

Abstract: The effect of a vacuum environment on welding of Cu-Bi (0.3%) electrical contacts has been investigated. The experiments have been planned in order to differentiate between the effects of cold welding, diffusion welding and percussion welding. Cold welding has no affect on newly prepared electrodes, but after the electrodes have been arced appreciably a small residual cold weld force is experienced. The diffusion weld strength is strongly dependent upon the contact force, the electrode temperature and the time in contact. The strongest weld forces are measured in the percussion weld experiment where the electrodes experience a high current prestrike arc as they close. It is also found in this study that the weld force decreases rapidly after the electrode faces are exposed to the residual gases in the vacuum. These results are discussed in terms of the chemisorption of residual gases and the real area of electrical contact. The effects of the change in nature of the electrode surfaces are discussed and a satisfactory qualitative explanation of the results is reached.

Reinforced metal matrix compound material - direct resistance joined

Abstract: The compound material comprises a metal matrix with at least locally aplied inset reinforcing material in wire, thread, fibre, strip or foil form, which are disposed on a former, is consolidated by a resistance welding type operation by direct electrical current passage causing melting at the various interfaces. The prefd. method is by means of electrode rolls between which the material is passed. The method requires lower pressure than other consolidation methods and is faster, therby avoiding undesirable diffusion effects and reducing damage to constituent materials. The material is used for high strength applications.

Electric resistance welding machines

Abstract: An electric resistance welding machine has several pairs of active electrodes below the work piece, such as mesh, being welded. Above the work piece a current bridge is provided for each pair of active electrodes, the current bridge being lowered in use so that the work piece is gripped at welding points between the active electrodes and the bridge, the welding current flowing from one active electrode, through the work piece at one welding point, across the current bridge, through the work piece of the other welding point, and back to the other of the pair of active electrodes.

Bonded joints and non-destructive testing: NDT of resistance spots, roll-spot, stitch and seam welds

Abstract: Several ultrasonic techniques have been developed for measurement of weld quality, these are largely applicable to the spot welding process. Some of these techniques have been devised for application after completion of welding as a separate process away from the welding machine. Others have been developed for use on the welding machine. Of these latter some have potential application to in process quality control. This article describes the welding process and reviews current techniques for quality assessment including ultrasonic techniques either in use or under development. To enable these developments to be viewed against the background of current resistance welding practice the definitions and terminology of the welding processes are explained and the present position of alternative quality assurance techniques is reviewed.

Process and apparatus for submerged arc welding

Abstract: A submerged arc welding process performed on adjacent longitudinal edges of a pipe blank. Two submerged arc welding units are supported on carriages which move on a stationary travel beam over the pipe blank. The welding units start welding at opposite ends of the longitudinal edges and weld toward each other until they meet. At that time one welding unit stops and returns while the second continues forward to overlap the welds while the fused flux remains electrically conductive at the area of overlap. After the second unit merges the welds, it returns.

Process for controlling spot welding and non-destructive testing of spot-welded joints

Abstract: A process for controlling spot welding by adjusting the electric energy used for the welding in accordance with the gradient of the rising branch of the curve plotting the electric resistance as a function of time. This process permits the maintenance of the overall welding time constant. At the same time the process permits non-destructive testing of a spot-welded joint by utilizing the gradient of the rising branch of the curve representing the welding resistance as a function of time. This gradient then indicates the quality of the spot weld.

Phenomena of the Molten Pool at High Current and High Speed MIG Welding

Abstract: The authors have studied the mechanism of bead formation, taking note of the discontinuous bead, particularly "humping bead" at high current and high speed welding. Following facts are clarified.1. In high current and high speed welding, the difference of temperature between the front part and the rear part of the molten pool is much greater than that in ordinary welding and this temperature difference causes strong surface-tension-stream directing from the front to the rear part of the pool resulting in the discontinuity of the bead.2. The authors have investigated some methods to prevent the formation of the discontinuous bead at high speed welding. The basic conceptions are as follows:a. Gravity control of the streamb. Decrease of temperature difference between the front and the rear part of the molten poolc. Decrease of surface tension of the molten poolThese methods aim to repress the strong stream from the front to the rear of the molten pool.For example, by elongating wire extension the arc takes the form of so-called "rotating arc", which heats the molten pool uhconcentratively different from concentrative heating of spray arc and acts to prevent discontinuity of the bead. Fig. 5 shows the critical relation to get continuous bead at high speed welding. This curve is applicable to every diameter of wire.3. The authors analized "melting efficiency" (see equ. 4) of the bead and clarified the relation between "melting efficiency and bead character". The results show that the welding speed at maximum melting efficiency is the limit to form the continuous bead.

The forge phase of friction welding. I, II

Abstract: Forge phase rigid and plastic region model of friction welding, deriving interfacial dispersion parameter of weld quality optimization

Multiple electrode resistance welding machine

Abstract: The subject of this invention is a multiple electrode resistance welding machine in which, by a particular configuration of the conductors which connect the power supply to the several welding positions, the DC resistance and the inductance of the circuit between the power supply and each of the welding guns is made constant. Through the use of the novel arrangement of secondary circuit conductors, the total resistance and the inductors in all of the circuits is the same so that the welding current and wave shape is the same in all of the secondary gun circuits and the weld quality at all of the welding points is uniform.

Resistance welding of aluminum

Abstract: Resistance welding such as spot welding of aluminum sheets and the like is greatly enhanced by the provision of a reacted silicate coating which substantially extends the useful life of welding electrodes by reducing pickup of aluminum on the electrode.

Method for rotary bi-axle type friction welding

Abstract: This disclosure relates to a method and apparatus for friction welding wherein an improved friction welding of a first and a second workpieces are carried out in a manner such that welded and plasticized workpieces are rapidly synchronized and also a larger thrust is provided at only the end stage of the welding so that change of metallic structure of welded workpieces due to cooling which tends to cause cracks in the welded portion is prevented. In order to carry out this improved friction welding, the apparatus for friction welding includes a second driving means for driving the second workpiece, detecting means for detecting the sum of the lengths of welded workpieces capable of providing a signal for interrupting the drive of the first workpiece and hydraulic systems capable of adjusting the thrust according to a signal from the detecting means.

Method for making a friction welded article

Abstract: First and second metal components to be joined at opposed interface surfaces by friction welding, the first component having greater hot strength than the second component, are friction welded by first shaping the interface surface of the first higher hot strength component prior to friction welding so that initial contact during friction welding is at the peripheral areas of the contacting surfaces. In one form, such shaped surface is in the form of a depression concave into the first component. The walls of the depression are disposed at an angle in the range of about 1* - 10* in respect to a plane normal to the friction welding axis of rotation.

Method of manufacturing large rotatable members by welding

Abstract: A method of producing large rotatable steel parts with circular cross-sections for construction of large machines such as shafts of generators and turbines. In a first stage a welding process is effected under a welding head for production of a weld connection in the central region of a welding gap between the parts. This central weld is subsequently circularly machined and the remaining peripheral groove is widened and formed of V shape. The parts are then welded at the groove, while the parts are rotated, by use of a welding process with a granulated welding flux.