Showing papers on "Electric resistance welding published in 1978"

Thermal Stresses in a Submerged-Arc Welded Joint Considering Phase Transformations

Abstract: Chalmers University of Technology, Sweden, has formulated two-dimensional finite-element models that satisfactorily represent the transient thermal and mechanical stress patterns occurring during the cooling of a butt weld produced by the submerged-arc welding of a heat-treated HT-36 steel alloy. The models offer a means of understanding the thermo-mechanical response caused by welding under various conditions without requiring the use of complex three-dimensional calculations.

Apparatus and method for sensing welding point in automatic welding apparatus

Abstract: An automatic welding apparatus comprises a welding torch including an electrode and a fixture for fixing a workpiece, and a relative positional relation of the welding torch and the workpiece fixture is controlled such that the electrode of the welding torch is moved to trace the welding line of the workpiece, whereby automatic welding is achieved. The automatic welding apparatus further comprises a switch for selectively connecting the electrode of the welding torch to a welding power supply or a detecting power supply, and a sensor for sensing a current or a voltage between the electrode and the workpiece when the electrode is switched to the detecting power supply, whereby the relative positional relation between the welding torch and the workpiece is detected in response to the output of the sensor, and thus a welding point or a welding line is sensed. In the case where the automatic welding apparatus is a wire extension type, adapted to successively feed the electrode in accordance with the progress of welding, a collet chuck for clamping the electrode to the welding torch is provided for fixing the length of the electrode from the welding torch on the occasion of the sensing mode.

Apparatus for connecting metallic parts by means of arc fusion welding

Abstract: An apparatus for connecting metallic parts, and metallic parts so produced, by means of arc fusion welding by producing a low volume welding seam (narrow gap welding), wherein the workpiece parts to be joined and forming a narrow gap are initially welded at their butt joint by means of, for instance, electron-beam welding, plasma-arc welding, laser-beam welding or argon arc-welding to produce a base seam with or without filler material, and thereafter the workpiece flanks forming the narrow gap are united by alternately depositing weld beads at first one and the other workpiece flank by submerged-arc welding

Electrode displacement monitoring in resistance welding

Abstract: One or two sensors are used to measure the displacement of a pair of electrodes relative to each other during resistance welding. The axis of the or each sensor is parallel to and as close as possible to the common alignment axis of the electrodes.

Method for preventing cracks below seams during plating and welding

Abstract: A method for preventing the development of cracks below seams during the plating and welding of material by employing a heat source for producing local heating of the regions of the material adjacent the welding zone.

Narrow weld-groove welding process and apparatus therefor

Abstract: A narrow weld-groove welding process, in which a bare welding wire is fed into a weld groove defined between the opposed surfaces of two pieces of metals for producing a metal arc therein for welding. In this process, a welding wire is subjected to a plastic deformation of a wave form, before being fed into a nozzle hole provided in a contact tip, and then the wire is fed into a nozzle hole, while maintaining elasticity tending to cause waving, whereby the tip of a welding wire being fed through a nozzle exit is automatically waved between the opposed surfaces of metals to be joined, with the tip of wire being alternately faced in the opposite directions, in response to the weaving motion thereof, with the feeding of the welding wire and progress of welding. In addition, the apparatus for use in a narrow weld-groove welding process is also disclosed.

High Power Laser Welding - 1978

Abstract: Current high power laser welding technology is reviewed. The nature of the beam-material interaction, the influence of laser, process and material parameters on welding response and the unique characteristics of the process are discussed. Examples are given of representative laser welding performance in ferrous and nonferrous alloys and selected illustrations are presented of weld mechanical properties. A relationship is noted for the dependence of maximum single-pass laser weld penetration on power and a range of laser welding applicability is delineated. Laser welding efficiency is identified and process advantages and disadvantages are compared. The potential for future utilization of lasers in welding is discussed.

Method of cold welding using ion beam technology

Abstract: A method for cold welding metal joints. In order to remove the contamination layer on the surface of the metal, an ion beam generator is used in a vacuum environment. A gas, such as xenon or argon, is ionized and accelerated toward the metal surface. The beam of gas effectively sputters away the surface oxides and contamination layer so that clean underlying metal is exposed in the area to be welded. The use of this method allows cold welding with minimal deformation. Both similar and dissimilar metals can be cold welded with this method.

Method of arc welding with reverse side cooling for obtaining highly tough large-diameter welded steel pipes

Abstract: An arc welding method for manufacture of a welded steel pipe wherein the edges of a steel plate bent into a pipe shape are welded together on one side for forming a pipe and then the seam line of the thus formed pipe is welded by a second welding operation at the side opposite to the side where the first welding was performed. During such second welding, the weld is cooled forcedly from the side where the first welding was performed. Such forced cooling compensates for any physical effects accompanying the welding and imparts elevated toughness to both the weld metal and the heat affected zone.

Method and apparatus for controlling welding operations during resistance welding

Abstract: A method of, and apparatus for, respectively controlling the start of welding and the termination of welding during continuous resistance welding with the aid of an alternating-current at a roll-welding machine, wherein at least at one measuring station or location arranged ahead or upstream of the welding station or location and the workpiece to be welded passing through the measuring station there is determined the position as a function of time of the leading end as well as the trailing end of the workpiece to be welded with respect to the frequency and the phase of the welding current. By means of a computer processing the determined value there is accommodated to one another the speed of the workpiece to be welded and the frequency and phase of the welding current in such a manner that the first welding spot and the last welding spot are applied at an adjustable spacing from the leading end and the trailing end, respectively, of the workpiece to be welded.

Method for making a bimetal resistance welding electrode

Abstract: A bi-metal resistance welding electrode has a dispersion strengthened copper tip and a high conductivity copper shank. The electrode is made by forming a tip member in two successive upsetting operations to produce a tip member having a coating of high conductivity copper covering substantially all of one end thereof. A solid, high conductivity copper, cylindrical billet is formed and brazed to the tip member at its coated end to form an extrusion blank. The extrusion blank is back extruded with the high conductivity copper material being worked substantially, while only partially back extruding the tip portion of the extrusion blank.

Method for welding bodies made of very hard or greatly refined armored steel, respectively, and structures made according to this method

Abstract: A method for welding bodies made of very hard or highly refined armor steel, particularly objects to be armored against the penetration of projectiles, flying bodies, splinters or the like, wherein armor steel bodies arranged in juxtaposition with a gap therebetween are provided, in the region of the root of the joint, with preferably one bar each, and/or a filler body of, in particular, an unalloyed steel is arranged in the joint so as to cover the joint gap. The armor steel bodies are welded together without preheating with a suitable ferritic welding material, of like base, under a protective gas atmosphere and after cooling of the weld seam from the welding heat to not less than 100° C., the weld seam is heated locally and progressively without any holding period to at least 450° C. and subsequently, without maintaining a certain ambient temperature and/or period of time, the weld seam is cooled to ambient temperature in air. Alternatively, a like-base layer of armor is locally applied onto a wall of armor steel from a suitable ferritic welding material in that the welding area, which has been cooled from the welding heat to no less than 100° C., is heated locally and progressively without any holding period to at least 450° C., and subsequently the weld region is cooled in air without maintaining a certain time period and only the last (uppermost) welded layer of the weld region is again locally reheated, before being cooled from the welding heat to below 100° C., at least 450° C. without holding period and subsequently again cooled in air to ambient temperature without maintaining a cetain time period and or temperature.

Method of producing seam welded tube

Abstract: A method of seam welding metal tube from a sheet metal blank wherein the sheet metal blank is provided with central key locating slots and pre-curled edges, then centrally located on a collapsible mandrel, having a heat sink liner extending therearound to a longitudinally extending gas gallery slot, by the key locating slots and then skid rolled therearound towards a longitudinally extending gas gallery slot for seam welding the curled edges while they are clamped to the collapsible mandrel over the gas gallery slot. Pre-curling the edges avoids upstanding edges at the seam weld and the method provides consistently reliable welds for tube blanks which may be manufactured in short lengths for, for example, the manufacture of bellows.

Method for welding of austenitic stainless steel piping

Abstract: A method for butt welding of austenitic stainless steel piping with forced cooling of the inside by the flow of a cooling medium comprises the steps of initially welding the pipe ends together by a root pass prior to the inflow of the cooling medium so as to prevent leakage of the medium to the outside, introducing an insert for constraining the flow of the cooling medium into the pipe, and welding the junction while forcing the medium to flow through the space between the insert and the surrounding wall of the pipe, the insert constructed so that it increases the flow velocity of the cooling medium to the maximum in the vicinity of the welded joint being formed.

Buildup welding of inclined surfaces

Abstract: A method of building up lines or layers of metal on a region of a workpiece, especially a region which terminates at the top of a vertical surface of the workpiece, by fusion arc welding, comprises: building up a barrier along at least one edge of the region, and this is along the top of the vertical surface when one exists, by welding with a low-power arc and then building up the remainder of the region against the barrier by welding with a much higher power arc, which is preferably of the submerged-arc type.

Energy beam welding with filler material

Abstract: In automatic energy beam welding, as electron beam welding, of workpiece edges which form a gap of varying width along the weld line, the amount of filler material needed for making up for the volume of the gap is determined by probing the size of the solidified weld bead at a surface of the workpiece and the rate of supply of filler material to the welding zone is controlled on the basis of the result of such determination such that the size is maintained between predetermined limits.

Apparatus for welding two profile or section rods by means of resistance welding, especially for welding two rails

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. The pivotal arms each having a centering mouth at their free end, the form of which is essentially matched to the profile or contour of the profile or section rods which are to be welded together.

Method for electroslag welding of metals

Abstract: A method for electroslag welding of metals whose density is less than thatf welding fluxes, is provided. The method is based on floating-up of drops of molten metal of the edges being welded and of the electrode in a slag whose density exceeds that of the metal. The floating-up metal drops form a metal bath on the surface of the slag bath, and crystallization of the metal bath produces a weld. In the course of welding, the electrode metal is fed into the slag bath in the upward direction, while the electrode metal melts and the weld is built up in the downward direction.

Method and device for welding in a thermally ionized gas

Abstract: A plasma-MIG welding system in which the power for establishing the MIG-arc is supplied to the consumable electrode at a point downstream of the non-consumable electrode.

Production of welded metal can barrel and device thereof

Abstract: PURPOSE: To obtain welded metal tube barrels which are neat, are provided with weld zones superior in corrosion resistant by inserting the lap weld faces of metal can barrels between the opposing faces of a pair of opposing parallel electrodes and pressure-welding the same by the specified method CONSTITUTION: A can barrel molding 1 whose side edges of a low carbon steel plate or the like of 014 to 035mm in plate thickness are overlapped at 01 to 1mm wide is inserted between parallel electrodes 4a, 4b having recesses 5a, 5b on the opposing faces in such a manner that the entire part of the welding faces overlap with the wire electrodes 10a, 10b of said electrodes, thence the molding is contacted to a mandrel 2 by a pressure wing 9 Next, the separately mentioned mechanism causes a pressure body 8 to apply the specified pressure, after which current is supplied to the electrodes The weld time is controlled to about 3 to 80msec by a timer Upon completion of welding, the pressure is released and the can barrel is delivered out, thus welding is repeatedly accomplished The wire electrodes 10a, 10b are so constituted as to be able to move after welding, if necessary COPYRIGHT: (C)1980,JPO&Japio

Inconel welding method of dissimilar material joint

Abstract: PURPOSE: To improve the strength of weld zone and welding efficiency by controlling the temperature of weld pass through water cooling at the time of Inconel welding the dissimilar material joints of austenite base stainless steel and ferrite steel. CONSTITUTION: A weld torch nozzle 1 and electrode 3 are disposed in the joint part and an Inconel welding material 6 is welded by generating arc between the joint part and electrode while blowing Ar gas 2. At this time, cooling water 9 is sprayed through the water injection holes 8 of a water supply pipe 7 disposed on the side opposite from the torch nozzle in the entire stage or part of the stage of the welding work to water cool the weld zone and weld side end part of the austenite base stainless steel 4. Thereby, the thermal stress affecting the low alloy steel material 5 such as of Cr-Mo steel or other may be eliminated and cracking and degradation of material quality may be prevented. COPYRIGHT: (C)1980,JPO&Japio

Welding method using a break away flux dam

Abstract: The invention relates to an improvement in a method of welding a first workpiece to a second workpiece which comprises utilizing the flux dam composition on each side of a weld groove to define a dam and electrical welding along the weld groove while adding flux thereto to maintain a slag blanket over a pool of molten weld metal in the groove.

Oscillating arc welding

Abstract: A welding process, such as a GMA welding process, employs a consumable electrode with the consumable electrode being oscillated back and forth over the surface of an object to which welding material is to be applied or across the gap between two pieces of metal to be welded together. At the ends of the swings of the consumable electrode an impact force is applied to the consumable electrode to interrupt its movement, thereby causing molten metal at the end of the consumable electrode from which the arc is struck to be impelled therefrom.

Method of resistance welding wires to a massive workpiece

Abstract: A method for producing strong resistance-welded joints between wires and massive workpieces, especially welded joints between nickel-plated copper wires and steel workpieces. The melting of the nickel coating is insured by producing locally high temperatures and pressures, due to the special configuration of the surface of the workpiece. The work surface is provided with bulges or protrusions which cause a concentration of electrical current and electrode pressure.

Welding of Railroad Rails—A Literature and Industry Survey

Abstract: Literature and industrial sources relating to methods for welding of railroad rails are surveyed. The welding processes included are thermite, flash, gas-pressure, and arc welding. Process and procedural descriptions, weldment properties, service performance in track, fabrication costs, and production rates are reviewed.

Flash butt welding apparatus

Abstract: A rectangular waveform voltage is applied between electrodes for welding by using a variable voltage-variable frequency type inverter as the power source for welding whereby the local short-circuit between workpieces can be immediately changed to the flash whereby the fine flash can be continuously generated to remarkably improve the quality of the welded part, and the voltage control can be attained without changing the voltage waveform.

Gas metal arc welding apparatus for repairing misaligned tube holes

Abstract: A welding apparatus including a nozzle assembly having a contact extension and a contact tip for guiding a consumable welding wire into a tube hole. The consumable welding wire is guided into the tube hole and an electric current is passed to the wire to produce an arc between the tip of the wire and the sidewall of the tube hole, melting the wire and supplying filler weld to the hole. The nozzle assembly has a gas nozzle; and, during the welding process, an inert gas is delivered into the tube hole through the gas nozzle.

Apparatus for monitoring and controlling a welding phenomenon in an electric resistance welding

Abstract: An apparatus for monitoring and controlling a welding phenomenon in an electric resistance welding process, which comprises a welding characteristics measuring instrument for carrying out digital measurement of at least one of high frequency welding characteristics, a welding phenomenon monitor circuit for detecting variations in the welding characteristics, and a welding phenomenon controller circuit for automatically adjusting a parameter of a welding power source or other welding conditions, wherein the welding characteristics include an oscillating frequency and an oscillating period of a high frequency used for the welding, and a phase difference between a high frequency voltage and a current. Changes in the welding characteristics occur in correspondence with the occurrence of periodic fluctuations in the shape of the high frequency welding current circuit formed in the material to be welded during high frequency electric resistance welding process.

Automatic tig welding method of pipe and pipe plate

Abstract: PURPOSE: To achieve the improvement in the toughness of weld heat affected zone and welding efficiency by welding a pipe and pipe plate while cooling the same by the pressure air or the like from the circumference of a welding torch at the time of subjecting the pipe and pipe plate to TIG arc welding. CONSTITUTION: The pipe 1 and pipe plate 3 belonging to a chemical apparatus such as methanol converter or the like are seal welded in a three o'clock welding posture. A welding torch 5 is made in double construction and pressure air, pressure carbonic acid gas or the like is jet out near the weld zone from the circumferential hole at the end of the outer nozzle 11 thereof, whereby the weld zone is cooled. Arc is generated between the welding torch 5 and the corner part of the end faces of the pipe 1 and pipe plate 2 and automatic welding is performed while the wedling torch 5 is being rotated along the circumferential direction of the pipe. According to this method, sound beads 9 are formed without becoming dropping beads. In addition, the weld heat effected zone 10 is suppressed of particle coarsening and the toughness is considerbly improved. Since the quantity of heat input may be increased, the considerably improvement in welding performance may be achieved as well. COPYRIGHT: (C)1980,JPO&Japio