Showing papers on "Electric resistance welding published in 1974"

Welding method for dissimilar metals

Abstract: A method for welding dissimilar metals, wherein a filler metal is deposited on one end of the aforesaid dissimilar metals to be jointed, said filler metal being of the same material as that of another of said dissimilar metals; the outer surface of the weld metal thus deposited is machined to provide a joint surface adapted for welding; and an electron beam welding is applied along the interface formed between said joint surface of said weld metal thus deposited and the joint surface of another of said dissimilar metals.

Welding system provided with wire feed and arc control

Abstract: In the process of arc welding with electrode wire feed there are many parameters which influence the quality of the welded joint. The welding system proposed provides considerable quality improvement, particularly in short-circuiting arc welding, reduces the dependence of the welding process upon the skill of the welder and greatly simplifies setting of the apparatus. A characteristic regulating parameter of the welding process is regulated so that the mean arc power remains substantially constant. Embodiments given by way of example illustrate ways of measuring and controlling the mean arc power, which, according to the insight on which the invention is based, is the factor which determines quality.

Apparatus for rotary bi-axle type friction welding

Abstract: This disclosure relates to an 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.

Welding of thermoplastics through resistance heating

Abstract: Surfaces of thermoplastic parts are welded by placing a star-shaped heating element in-between the parts. The element is a coiled wire jacketed in plastic which melts during the welding. The resulting bond covers a relatively large area. The method is used for providing a saddle flange to a thermoplastic tube.

Apparatus for ultrasonic welding

Abstract: Apparatus for welding a metallic component to a non-metallic component which involves interposing an aluminum layer between metallic and non-metallic components, preheating the metallic component and the aluminum layer, preferably by induction heating, to a temperature of at least 250*C and then subjecting the components to ultrasonic welding.

Method of welding tanks

Abstract: A semi automatic machine for welding fuel tanks of a general cylindrical configuration. The machine is adjustable to handle more than one size tank and once properly adjusted will accurately position and hold the tank for the longitudinal side seam weld as well as slowly rotating the cylinder for the two end seam welds. In addition to properly positioning and holding the tank during the side seam welding process, the machine also positions the end members and forces them into the opposite ends of the side seam welded cylinder assuring a properly aligned and fitted tank prior to the end seam welding process.

Electrical resistance weld method and apparatus

Abstract: The metallic parts to be welded are first pressed together at the welding point between the electrodes of a welding tool. Thereafter the weld current is furnished to the electrodes in form of at least two subsequent pulses. The first pulse is set at a lower energy than the successive one and serves to pre-seat the metallic parts for the second pulse.

Process for welding low-alloy steels containing niobium

Abstract: A process for welding high-strength low-alloy steels containing niobium, producing thereby weld deposits which are of improved strength and toughness in comparison to weld deposits heretofore produced in accordance with prior art techniques. The process comprises introducing controlled amounts of vanadium and/or titanium into the molten weld metal along with other alloying elements in a manner to form an alloyed weld deposit in which the concentration of vanadium and/or titanium is carefully controlled in relationship to the niobium content present. The invention also relates to welded structures produced in accordance with the process aspects of the invention, as well as consumable welding electrode compositions for use in the practice of the method.

Welding machine supply system - using transistorized frequency changer and transformer or/and rectifier

Abstract: An electric welding appts. includes a frequency change which converts the mains a.c. supply voltage from a 50 Hz frequency to a frequency of up to 25000 Hz. A transformer produces from the supply voltage (380 V) a voltage for arc welding (15-40 V) or for resistance welding (2-20V) or, by an added rectifier, to a d.c. voltage. This results in an appts. of small weight (5-15 Kg) if fully transistorised. The equipment is easy to handle and has a universal application.

Method of and apparatus for strip flash welding

Abstract: A method of and apparatus for welding metal strips in which the strip ends are cleaned, to ensure good welding conditions, prior to being sheared and welded, the three operations taking place in a clamp position.

Process for welding aluminum and aluminum alloys in horizontal welding position

Abstract: Aluminum and aluminum alloys are welded in a horizontal welding position in which the base metals to be welded are vertically disposed in abutting relationship with the welding groove opened sidewise by oscillating the tip of the welding electrode in the widthwise direction of the abutted base metals and welding the base metals while maintaining the angle formed by the surface of the molten pool and the electrode on the advancing side thereof greater than 90°. The surface of the molten pool as used herein is defined as one which is parallel to the crater surface of the weld which results upon termination of welding by extinction of the welding arc.

Capacitor-discharge stud welding machine

Abstract: In the machine disclosed, two flexible welding cables carry capacitor discharge current from a capacitor bank in a capacitor charging welding set and produce a movable electrical connection between a welding gun and a base material onto which a welding element is to be welded. Both welding cables are fixed with respect to one another. According to one embodiment of the invention the cables are arranged to be equidistant from one another substantially over their entire length. They are arranged as close as possible to each other within the breakdown limits of the insulation. The cables are of a predetermined length.

Electron beam butt welding - using filler strap in and/or over butt joint gap

Abstract: To join two abutting metal plates by electron beam welding, a bar of a filler metal is laid over a gap at the butt joint. The electron beam is directed on top of this bar so that it melts and fills the gap. The gap is so dimensioned that the molten metal just fills it. The gap can be partly filled up by a filler metal insert or powder prior to welding. A copper backing plate can be used at the other side of the joint. This eliminates welding defects (unilateral fusion, arching) which are common in conventional electron beam welding. A simple electron gun is suitable for this method. The butt joint requires no careful preparation and can be flame cut.

Stator core construction for small motors - with external notches for taking seam welds avoids use of axial rivets in core

Abstract: The application is to small motors which have to fit in confined spaces and therefore allow insufficient room in the core back for axial rivets. The stator punchings (4) have notches (6) on their outer perimeter, and are assembled with these notches in line. Each notch has a central land (7) thus a continuous ridge is formed on assembly. The seam weld runs along each ridge which assists in centering the weld. Typically the welding is done under an inert gas . The height of the weld is such that the core ends can be reduced in diameter to take end caps without cutting into the seams.

Welding machine with a disassemblable column

Abstract: A resistance welding machine for automatically effecting several programmed welding operations, wherein a column, movably supported on a support, carries a unit of operative members which has an elongated shape and can be inserted from the bottom into the column; connection means are provided on the column and the insertable unit for automatically establishing electrical and fluidical connections as a consequence of the mechanical connection of the members.

Resistance welding parameter profile for spot welding aluminum

Abstract: As tip force is increased, there is a larger tolerance in the variation of the other welding parameters, i.e., current and weld duration where good weld quality is obtained. Longer weld current duration reduces the tendency to have cracks appearing in the sheet under the electrodes. There is a near linear correlation between welding current and shear strength which is independent of the number of weld cycles and tip force used.

Method for underwater frictional welding of metallic material

Abstract: This invention provides a method for underwater frictional welding of metallic articles, which method comprises preparatorily wrapping a heat insulating material such as tape around the periphery at the terminal face of each of the metallic articles subjected to welding, abutting under pressure the terminal faces of the metallic articles against each other and welding the confronting ends of the metallic articles by utilizing the frictional heat produced in the terminal faces by the relative rotary motion and the pressure exerted in the axial direction.

Laminated packaging sheet - with film section directed towards welding tool having higher melting temperature than tool temperature

Abstract: Laminated packaging sheet, esp. for cigarette packets, has at least one layer of thermoplastic resin for the formation of sections for the prodn. of packets by thermal welding, at least the surface region of the film section directed towards the heated welding tool having a melting temp. lying above the temp. of the welding tool. Inner resin layer pref. consists of polyethylene. Enables the weldable sections to be welded without contacting the welding tool, thus avoiding the adherence of resin residues to the tool. Welded sections of better quality are produced.

Electric resistance pressure wlding of grids - made from bars and beams with pronounced difference in cross-section

Abstract: Process for joining two metal pieces which cross each other, by means of electric resistance pressure welding, where the two metal pieces possess a pronounced difference in cross-section thickness, the piece with the large section is provided with a continuous rib possessing a cross-section between 0.5 and 2 times that of the piece with the small section, and welding is achieved by applying the piece with small section to the rib. The process is pref. used to make a grid from profiled beams possessing a flange provided with a rib having the same cross-section as transverse bars which are welded to the ribs. Method permits the electric resistance welding of parts with a small cross-section to parts with a large cross-section.

Cooling electrodes of resistance welding machines - by evaporating coolant in or adjacent the electrodes

Abstract: A cavity is formed in the electrode holder, the electrode or in both. Pipes are led to the cavity for supplying coolant and for sucking away evapd. coolant. When using a hollow electrode a protective shell may be provided between the electrode and coolant. The space between the shell and the electrode can be filled with a good heat conductor. The evapd. coolant appts. may be employed for massive electrodes in point and lump welding machines as well as rotating disc electrodes in seam welding machines.

Installation for the automatic feed of welding wires

Abstract: An installation for the automatic feed of welding wires for a welding torch provided for the treatment of workpieces, in which means are provided to weld together the welding wires supplied in rod shape in a fully automatic manner by welding the same together into an endless rod with simultaneous continued forward movement of the welding wires in the direction toward the welding torch.

Welding Studies on Arc-Cast Molybdenum

Abstract: Although molybdenum has several metallurgical characteris­ tics that make its fabrication (espe­ cially by welding) difficult, it has some important properties that give it good potential for use in the next gen­ eration of nuclear reactors or in radio- isotope thermoelectric generators. To increase our understanding of the characteristics that have limited the use of molybdenum, a program was undertaken in support of the Molten Salt Breeder Reactor in which very complex prototype components for a chemical processing test stand were fabricated from arc-cast molybdenum by extrusion, machining, welding, and brazing. This paper presents some of the results of the welding development portion of that program. Procedures were developed for clean­ ing and stress-relieving this material before welding and for making helium-leak-tight welds by both the gas tungsten-arc and electron beam processes. A commercial orbiting-arc weld head was modified so that mo­ lybdenum tubing could be field joined

Variable wall thickness rotation symmetrical components - made by resistance welding of semi circular blanks

Abstract: Rotation symmetrical hollow differential wall thickness components can be mfd. from cheap stamped or forged semi - circular blanks, the interfaces of which project above a plane through the axis of the finished component, joined by electric resistance welding. Welding is pref. carried out with die like electrodes. The method provides an economical route for making ball journals, track rods etc.

Rounding-off frames - prior to feeding them to an automatic resistance welding machine

Abstract: Frames are rounded-off and fed to an automatic welding station by an appts employig a set of rollers for the rounding-off of the sheet metal For the roller set there is a first guide, as well as a guide that can be raised by a specific amount or lowered during the rounding-off operation There is also a second guide positioned opposite to the first guide

Technique for ensuring spot welds in a standard welding range

Abstract: Features which influence spot weld quality are included. The main welding parameters to achieve quality control are welding current, welding time and electrode force. Methods for achieving required spot diameters, typical welding ranges and use of destructive testing are described.

Solid state and fusion resistance spot welding of TD-NiCr sheet

Abstract: By using specially processed TD-NiCr sheet in both 0.4-mm (0.015-in.) and 1.6-mm (0.062-in.) thicknesses and carefully selected welding procedures, solid state resistance spot welds were produced which, after postheating at 1200 C, were indistinguishable from the parent material. Stress-rupture shear tests of single-spot lap joints in 0.4-mm (0.015-in.) thick sheet showed that these welds were as strong as the parent material. Similar results were obtained in tensile-shear tests at room temperature and 1100 C and in fatigue tests. Conventional fusion spot welds in commercial sheet were unsatisfactory because of poor stress-rupture shear properties resulting from metallurgical damage to the parent material.

Studies on Prevention of End Cracking in One Side Automatic Welding (2nd Report)

Abstract: Recently one sided automatic welding has widely been prevailed in the assemble stage of Japanese shipyards. As one of the problems of welding procedure, as well as any other welding techniques, cracking which sometimes occurs near the end of weld, has become an important problem.The authors have proposed the calculation technique in the seam welding. The most significant feature of the method differing from the ordinary welding thermal stress analysis is that the conditions of calculation are simulated to be those of more realistic welding procedures.Then, the following assumptions are imposed in order to calculate stress and strain during welding.(1) Before welding, specimens are connected by tack welds and prepared edges are free boundaries.(2) Molten region containing arc tip is free from stress.(3) After the arc passed by, the plates are connected by solidifying of the molten pool, that is, free prepared edge changes to supported one as temperature is cooled down.(4) When the arc passed through a tack weld, it should be melted away and free from stress.In order to calculate the thermal stress analysis during welding, firstly we solved un-stationary heat conduction problems and obtained temperature distribution during welding. Based on the calculated temperature distribution, we analysed uncoupled thermal stress problems by using the finite element method, and conclusively showed that one of the main causes of end cracking is the transient tensile stresses generated near the end part of weldment when the stress re-distribution is taken place due to the melting of the last tack weld.To endorse the numerical calculation by the proposed method, experiments are carried out and it is confirmed that the method could be applicable to this kind of transient welding stress-strain state with time depending varying boundary conditions.

Seam welding large pipes - avoiding rupture as a result of differential stresses

Abstract: The edges of the initial sheet are joined together by tack welding or root-face welding, and subsequently filled by fusion welding. During and/or immediately after fusion welding at least sections of the pipe ends, particularly those outside the welding zone, are heated and heating is continued until the weld seam has cooled to exhibit the required strength.

Direct current portable gun welder system

Abstract: Portable direct current resistance welding apparatus incorporating a flexible cable assembly comprising a pair of flexible conductors maintained at a fixed distance from one another with restraining means which prevent the separate cables from moving one with respect to the other. A flexible sleeve holds the conductors in parallel relationship to one another at a distance of at least four inches by means of a multiplicity of separating and restraining means fastened to the sleeve at intervals along its length while retaining full flexibility in the cable assembly.