Showing papers on "Arc welding published in 1972"

Mechanism of ripple formation during weld solidification

Abstract: The formation of ripples on the surfaces of GTA spot and seam weld surfaces in thin metal sheet was investigated by high speed motion pictures. The ripples are observed to form solely due to oscillation of the weld pool during solidification; no other mechanism for ripple formation was found. Weld pools were melted through thin metal sheets while a high speed camera observed the melting and solidification events on the bottom surface of the pool opposite the arc. When welding power is supplied from storage batteries, the weld pool surface shows virtually no oscillation while the arc is on. Shutting off of this arc suddenly releases the plasma pressure which was stretching the pool surfaces, setting the pool into oscillation like a struck drumskin. Solidification during this oscillation results in rippled surfaces. When a single phase full-wave rectified conventional dc welding power supply is used, the pool surface is observed to oscillate at 120 hertz. When this arc is shut off, the pool changes oscillation frequency in a fraction of a second from the frequency imposed by the pulsating plasma pressure to its own natural frequency. Pool oscillation periods after the arc is shut off are measured on the film strips. If the pool is considered to be a stretched membrane with surface tension providing the stretching force, a theoretical surface tension can be calculated from the oscillation period, pool mass and pool geometry. Agreement of the calculated surface tension values with published surface tension values for several metals demonstrates that the stretched membrane model adequately describes the pool oscillations. By counting the number of pool oscillations in the films and counting the number of ripples on solidified spot welds afterwards, a one-to-one correlation is established between ripples and pool oscillations. When a seam weld is made using storage batteries as the welding random disturbances of the pool surface are observed. Each disturbance leaves a few ripples before it damps out.

Method for short circuit metal transfer arc welding

Abstract: The method and system of the present invention minimizes weld spatter through control of the short circuit current and through control over the short circuit and arc time intervals.

Welding power source

Abstract: Metal arc welding apparatus, primarily intended for short-circuit welding, including a first D.C. power supply for maintaining an arc between a consumable electrode and a workpiece and a control circuit responsive to a short-circuit detector for coupling a second D.C. power supply, substantially without inductance, to the welding circuit after a delay. Preferably a further detector senses the impending rupture of the short-circuit and the control circuit acts to reduce the current before the rupture takes place.

Self-shielding cored wire to weld cast iron

Abstract: A cored wire welding electrode for welding cast iron having an outer sheath made of nickel or a nickel-iron alloy and a powdered core composition containing copresent metallic magnesium and graphite and slag-forming and alloying ingredients. The electrode is particularly useful for open-arc welding of cast iron to itself and to compatible metals.

Manufacture of electrical metallic tubing

Abstract: Electrical metallic tubing is manufactured from galvanized steel strip by forming the strip into tubular shape, welding the edges together and replacing the zinc lost in welding by gas or arc metallizing the weld zone first with aluminum and then with zinc.

Apparatus and method for welding joints between metal shapes

Abstract: A traveling electric arc welding apparatus using gas shielded consumable wire electrode, comprises a welding head mounted on a traveling carriage. The mounting means provide for angular shifting of the head about two different axes. Both such axes are in or near and closely parallel to the plane of the weld; e.g., in welding pipeline girth joints one axis lying as nearly as convenient in the plane of the weld is also as nearly as convenient tangential to the weld circle and thus passes near or, if desired, through the locus of the arc. The direction of feeding electrode material with respect to the weld plane is accurately set by movement about this first axis. The other axis is perpendicular to the first and lies generally in the weld plane. Means are provided for accurately aligning and setting the welding head laterally with respect to the plane of the joint; i.e., along the axis of the work in the case of a pipeline joint, by shifting the head about the second axis. Other positioning means are provided to adjust, pre-set and fix the distance or spacing of the welding nozzle from the noint. Means which can be inactivated, if desired, are included for oscillating the head back and forth across the weld path as for filling a wider gap or for capping. Quick release means permit raising the head from the work and returning it to a precisely determined working position.

Stainless steel with high resistance against corrosion and welding cracks

Abstract: Stainless steel with high resistance against corrosion and welding cracks, consisting of carbon, silicon, manganese, nickel, chromium, copper and the remainder of iron with an inevitable amount of impurity. The contents of the aforesaid ingredient elements of the stainless steel are so related with each other that the value of the following austenite/ferrite ratio is kept equal to or less than 1.06. The stainless steel may contain a limited amount of molybdenum, niobium, titanium, and tantalum, with a modified austenite/ferrite ratio. The stainless steel is advantageously used to make heat exchangers in processes employing automatic tungsten inert gas arc welding techniques.

Power propelled welding and cutting apparatus

Abstract: Power propelled apparatus for welding, cutting and similar work operations, in which a wheel supported carriage attached to an elongate workpiece is movably guided therealong while performing the particular work operation along a desired locus line on the workpiece, the attached carriage having driving elements operable into clamped driving engagement with a portion of the workpiece, for example, the web of an I-member or other structural member. Appropriate tool means, such as one or more cutting torches, welding torches or the like, are mounted on the carriage and are continuously automatically oriented so as to track the locus line during carriage movement and perform the work operation therealong. For arc welding use, the torch has a nozzle into which an appropriate gas is fed, together with a welding electrode wire supplied from a source on the carriage. Adjustable control means provides for variations to meet different operating requirements, and includes means for automatically stopping and shutting off the apparatus upon its reaching the end of the workpiece.

Method for electrical arc welding

Abstract: A method of electrical arc welding which may be effected in various welding positions by the use of at least one electrode of substantially rectangular cross section, the electrode tip of which is square-edged or shaped to fit with the shape of a groove formed between workpieces to be welded, the electrode being disposed in such a way as to render the widthwise direction thereof oriented substantially at right angles to the weld line along which a weld is to be formed. Also disclosed is an apparatus for electrical arc welding which is capable of performing the concurrently proposed arc welding method.

Pulse welding processes

Abstract: A metal arc welding process is described in which the arc is cyclically oscillated across and/or along the weld jointline during a weld, and in which the phase of the cyclic oscillations is correlated with the phase of a periodic metal transfer from the electrode to the workpiece such that each transference of metal takes place at a preselected instant during the cyclic movement of the arc.

Arc welding coated electrode

Abstract: A multi-coated stick electrode having an inner layer surrounding a metal core wire and containing a majority of the arc stabilizers in said electrode. The outer layers contain a majority of the metal powder.

Welding gun means for feeding and holding head-bearing studs or the like

Abstract: A stud retaining collet enables a welding gun successively to receive and hold in welding position studs or the like having circumferentially enlarged head portions. The improved collet, especially useful in arc welding, has a base which, with an associated mechanism of the gun, effects non-spurting stud retention against forces feeding the studs and also is able to conduct the welding current to the stud.

Welding of high strength steels

Abstract: Brief information is presented on the composition and properties of high-strength steels. Questions of their weldability are discussed, modern concepts of the causes and mechanism of cold and hot cracking are set forth and ways of preventing them are suggested. Information about the properties of weld joints, welding materials and conditions employed for welding in an atmosphere of protective gases, automatic welding under flux, electroslag, electron beam and diffusion welding of high-strength steels is included.

Lead battery welding method and apparatus

Abstract: A welding method for fusing lead components together in a lead-containing electrochemical cell is disclosed together with apparatus for carrying out the method. The method includes forming an ingot-like mold around the lead components to be welded, the walls of the mold being comprised of a material having a high softening point, good thermal conductivity and arc-erosion resistance. Arc welding of the components utilizing an inert-gas-shield nonconsumable electrode, e.g. tungsten, is accomplished by passing the electrode over a weldable surface formed by the lead components in an oscillating path at a controlled speed and welding current to permit the lead components to melt and flow into the ingot-like mold while simultaneously controlling heat transfer through the adjacent mold walls. The resultant weld is of low internal impedance and is relatively thick for increased oxidation and corrosion resistance during operation of the battery.

Method and apparatus for heat treating welded joints

Abstract: A series of torches mounted on a single traveling carrier and spaced apart in sequence are passed along a newly welded joint such as a girth joint in a pipeline to heat the metal and relieve high hardness commonly found in the zone adjacent deposited weld metal. The invention is used especially to relieve heat induced stresses in electric arc welding of large work pieces, such as thick walled pipes. Acetylene or other high energy fuel is supplied at a closely controlled rate to each torch. All torches are carried along the joint in a group at a predetermined and controlled rate. Spacing between each torch and the work is carefully adjusted and maintained to control the sequential heat inputs into the interior of the work metal. The first torch applies high intensity heat preferably directly on the weld with succeeding torches apply progressively softer flames. The critical area along the weld thus is quickly brought to austenitic temperature range, followed by slower heating and then by slow cooling, to relieve stress and/or to correct grain growth and related crystalline conditions in the metal. A series of four torches attached to a self-propelled and track-guided carrier are preferred. Since the torches are spaced progressively farther and farther from the work surface, the breadth of heat application by successive torches is progressively widened while heat intensity is reduced. At all times the surface temperature remains within tolerance limits.

Current transfer in connection with electric welding

Abstract: In electric welding utilizing a wire to supply metal to a weld area a current is supplied to the wire as the wire is continuously advanced to the weld area. In accordance with the invention the current can be effectively supplied to the wire utilizing a plurality of electrically conductive rollers having surfaces which engage the wire. These rollers roll in synchronism with the wire and transfer current supplied to them to the wire.

Method and means for removing smoke from open arc welding operations

Abstract: Apparatus for removing the smoke and fumes generated by an electric welding arc wherein an exhaust tube is placed in the vicinity of the source and a shield is placed between the arc and the exhaust tube, intake port, nozzle and contact tip, so designed that the smoke and fumes will be efficiently collected without undue heating or a rapid buildup of weld spatter on the exhaust tube, intake port, nozzle and contact tip surfaces.

Method and apparatus for controlling arc in gas shield arc welding

Abstract: In a gas shield arc welding, a stream of a control gas is blown against the end of an electrode generating arc to deflect the arc in the direction of the control gas jet stream. An arc-generating position of a joint to be welded is controlled by changing the momentum and/or direction of the control gas jet stream.

Method of adjusting the cooling speed of welds

Abstract: A weld zone formed by continuous electric welding is cooled by applying a mist jet of cooling water and the cooling speed is adjusted by adjusting the weight ratio of the cooling water to pressurized air utilized to form the mist and by adjusting the velocity of the mist jet.

Magnetic control of gas tungsten-arc welding process

Abstract: The possibility of increasing the welding speed in the gas tungsten-arc welding process by using external magnetic fields was investigated. The effects of a constant, transverse magnetic field applied to the arc were studied. Nine percent nickel steel and aluminum alloys types 2021, 6061 and 5454 were the materials used for this investigation. Type 4043 aluminum was used as a filler wire for aluminum and Inconel 625 for the 9% Ni steel weld specimens. Most of the welds were made without the addition of filler metal. All the weld specimens were of bead on plate type. By applying transverse magnetic fields, the maximum welding speed at which undercut-free welds could be obtained was increased considerably. The 9% Ni steel responded exceptionally well to the applied magnetic fields. The magnetic field strength required to produce a satisfactory bead appearance varied with current and travel speed. The arc deflection is consistent with the motor rule. It is suggested that the electromagnetic pumping action of the interacting self and applied magnetic fields produces an improvement in bead appearance.

High silicon over-laying alloy

Abstract: 1275007 Welding by fusion NIPPON SILICOLLOY KOGYO KK 16 Sept 1970 44275/70 Heading B3R [Also in Division C7] A hard-surfacing alloy comprises:- the balance, apart from impurities, being Fe. The alloy may be applied to a workpiece by arc welding using an A.I.S.I., stainless steel, 3A04-L (i.e. < 0A03% C, <1% Si, <2% Mn, 9-13% Ni and 18-28% Cr) electrode coated with appropriate amounts of Si, Mn, Mo, W, Cu &c.

Method for underwater arc welding

Abstract: According to the method of this invention water is kept away from the arc in underwater arc welding by means of a gas under a pressure greater than that of the water and, preferably, the wire feeding unit, welding gun, and electrode wire of the gas shielded, metal arc welding apparatus to be used underwater are enclosed in air-tight and water-tight containers. The containers and conduits are then internally pressurized with a shield gas to prevent the entry of water. The welding gun or at least its nozzle is inserted through a flexible sealed orifice in a small local housing chamber having a second opening. This second opening is placed against the work-piece to be welded. Shielding gas is supplied to the housing chamber at a pressure greater than the surrounding water to force water from the chamber and permit welding to take place in a region free of water.

Diffusion welding in air

Abstract: Solid state welding a butt joint by fusion welding the peripheral surfaces to form a seal, autogenetically cleaning the faying or mating surfaces of the joint by heating the abutting surfaces to 1,200 DEG C., and heating to the diffusion welding temperature in air.

Welding apparatus for interconnecting flanges

Abstract: An electric welding apparatus for interconnecting abutting flanges formed by metal sheets comprises a platform arranged as a unit which is separate from an associated welding transformer. On the platform there are arranged clamping rollers for electrical welding and for driving engagement with the flanges as well as driving means operatively connected with the clamping rollers for propelling the platform along the flanges. The platform is supported by supporting members which are adjustable with respect to the platform enabling the position of the clamping members to be adjusted with respect to a transverse and a longitudinal axis of the platform.

Arc welding using a consumable electrode - with pulsating stream of carbon dioxide directed onto molten end of the electrode

Abstract: Process fo rarc welding with a consumable electrode, esp. protective gas welding using carbon dioxide gas, the novelty being that the consumable end of the electrode, esp. protective gas welding using carbon dioxide gas, the novelty being that the consumable end of the electrode is subjected to a gas stream with a predetermined frequency of pulsation. The pulsating gas stream pref. has a frequency of 1-200 Hz, esp. 1-50 Hz, and forms a ring round the electrode, the stream pref. being surrounded by a continuously flowing gas curtain. Allows the controlled, predetermined transfer of drops of molten metal from the end of the electrode which is largely independent of the influence of gravity; smaller drops are obtd., reducing the risk of short circuits, and increased penetration results.

Welding current source

Abstract: An arc welding current source in which two rectifiers are connected in antiparallel relationship in the current output circuit to provide A.C. potential to the welding electrode, one of the rectifiers being automatically switched off during idling to provide D.C. potential at the electrode whereby current to the electrode is continuously maintained during the switch from A.C. to D.C.

Method of intermittent arc welding using potassium and magnesium electrode additives

Abstract: A consumable electrode arc welding process which can be used for welding in the horizontal, vertical or overhead positions which comprises applying a pulsating current to a welding electrode so that at recurring intervals a welding arc is periodically established and extinguished wherein the period of time in which the arc is extinguished ranges from 0.001 to 0.01 seconds. the arc is established for a first interval of between 0.001 to 0.01 seconds and wherein the ratio of the interval during which the arc is extinguished to the full cycle is 0.1 to 0.7. A consumable electrode useful in a consumable electrode arc welding process which comprises a mixture of potassium and magnesium or an alloy thereof wherein the quantity of potassium multiplied by the square of the quantity of magnesium exceeds 0.02. A consumable electrode arc welding apparatus comprising a welding current control circuit, a first circuit having at least one semiconductor controlled rectifying element connected in series with a welding electrode for enabling a welding current to be applied thereto, and a second circuit for controlling the gate of said element for effecting phase control such that when said welding current is applied to said electrode, it is of the pulsing type.