Showing papers on "Welding published in 1971"

Analysis of thermal elastic-plastic stress and strain during welding by finite element method

Abstract: It is well known that welding thermal stresses and resulting residual stresses influence the strength of welded construction, causing troubles such as brittle fracture, buckling and weld cracking. At the instant of welding, a limited portion of the welded joint is heated up to a very high temperature and cooled down to room temperature. In the thermal cycle which takes place, the temperature distribution changes with time and it affects the mechanical properties of the metals. In order to perform a reliable theoretical analysis, the above mentioned factors should be taken into account. The authors developed a method of theoretical analysis of this problem based on the finite element method, with consideration of the effects of changes in the modulus of elasticity, yield stress and the coefficient of linear thermal expansion of the metal with temperature. They analysed thermal transient stresses induced in a butt weld under a moving electrode and also in a fillet weld in the courses of the first and second beads and obtained various information on thermal stress history in the process of welding. Examples verifying usefulness of the method are cited.

Apparatus for vibration welding of sheet materials

Abstract: Ultrasonic apparatus for welding thermoplastic sheetlike elements wherein a plurality of spaced ultrasonic vibration transmitting members having working surfaces in contact with one side of the sheet-like elements. The working surfaces cooperate with opposing spaced anvil surfaces located on the opposite side of the sheetlike elements for producing welds in the material therebetween. Means are provided to advance the sheet-like elements between the members and the anvil surfaces, said members being arranged so that every point across the width of one of the sheet-like elements comes into contact with at least one of said working surfaces.

Laser welding plastic tubes

Abstract: A method of welding a plastic end member to an unstepped, plastic tubular body which comprises positioning the end member within the body and then irradiating the area to be welded with a laser beam for a specified time sufficient to achieve the desired weld while simultaneously imparting relative rotational motion between the beam and the area to be welded.

Welding gun cooling structure and electrode tip retainer

Abstract: A welding gun and cable apparatus utilizing quick connect and disconnect couplings to provide electrical current and shielding gas to a welding gun as well as a welding electrode if desired. The welding gun includes an elongate body having a gas passage and a passage formed between the body and an outer covering through which air flows by connection to cool the body. Additionally the gas passage may also contain a liner with radially sprung fingers at one end to outwardly bias against a welding tip to retain the welding tip in a nozzle portion.

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 of welding thermoplastic band for use in packing machine as well as apparatus relevant thereto

Abstract: A method of welding applicable to a packing machine for use in strapping the package with a thermoplastic band, which employs an apparatus comprising; a slide plate supporting the overlap portions of the plastic band to be welded; a heat plate which is disposed parallel to the direction of strain of the strapping band and is devised to melt the overlap portions of the plastic band after its advance with the retreat of said slide plate; and a press bar which supports said plastic band at the time of melting and presses the melted overlap portion of said plastic band against the slide plate after the retreat of the heat plate to thereby weld them together.

Traveling welding apparatus

Abstract: A welding apparatus adapted to travel along a predetermined path, form a weld along such path, includes a welding head, means for mounting the head on a traveling carriage, means for supplying electrode material to said head, and means for continuously and/or occasionally changing the alignment and/or angular position of the head with respect to the work being welded in order to apply molten electrode material in a variable pattern and/or at variable angles of projection.

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.

Method of friction welding

Abstract: A friction welded metallic article such as a fluid directing element for turbomachinery apparatus has a cast airfoil and a wrought base joined by friction welding. One such article having a hollow interior portion is made from a hollow or cored casting and a wrought base member. There is provided a metal airfoil casting having a hollow interior portion and an enlarged foot including an interface portion. Also provided is a wrought metal base portion including an interface portion. Interface surfaces of the interface portions are placed in spaced apart opposed relationship and then the airfoil casting and the wrought base member are friction welded at their interface portions.

Some Problems in Welding Inconel 718 There are problems in welding Inconel 718—obtaining good penetration, micro-fissuring, and developing adequate impact strength and ductility—but these problems can be overcome by adequate control and selection of the proper solution heat treatments.

Abstract: Penetration In general, Inconel 718 has very good weldability. Welding tests were made using gas metal-arc (GMA) and gas tungsten arc (GTA) processes and satisfactory results were obtained. Welds were also made in the unaged and aged conditions and no major difficulties arose. The one problem always encountered was the difficulty of obtaining good penetration with the root pass. This is encountered in most nickel-base alloys and is due to the poor fluidity of the molten metal. It was therefore decided to study this aspect more closely and to try to

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.

Electrode for arc welding in air

Abstract: An electrode for electric arc welding in air containing alkali metal composites which comprise an alkali metal oxide in combination with one or more metal compounds of acidic or amphoteric nature, preferably iron oxide, manganese oxide, aluminum oxide or silicon dioxide. The alkali metal composite is less hygroscopic than the alkali metal compound it contains and is capable of being reduced to elemental alkali metal in the welding arc by reducing agents contained in the electrode. The alkali metal composite is provided in sufficient quantity so that the alkali metal obtained therefrom reduces the nitrogen content of the weld metal sufficiently to suppress nitrogen boil in the weld metal. Certain metal oxides and fluorides, preferably oxides of silicon, calcium, or aluminum and fluorides of calcium, barium, lithium or sodium are moisture barrier materials and may be included in the alkali metal composite to further enhance its resistance to absorption of moisture from the air.

Tubular composite welding wire filled with potassium compounds containing flux

Abstract: A tubular composite welding wire for use in the automatic or semi-automatic welding process, which comprises:

Magnetic pulse welding using spaced proximity conductor

Abstract: Method and apparatus for performing a work function such as forming, welding, forging, or cutting on one or more electrically conductive workpieces. Work force is a pulse of magnetic pressure produced about a proximity conductor which is positioned closely adjacent the portion of the workpiece to be worked on and which is in conductive electrical connection with said portion of the workpiece.

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.

Magnetic control of arc environment

Abstract: Control means for the arc of an automatic DC electric welding device comprising an electromagnet with its magnetic poles aligned perpendicular to the arc and the seam to be welded and providing a preselected and optimized magnetized environment for the arc. A Hall-effect probe is located immediately ahead of the welding arc to detect the magnitude and direction of the effect on the magnetic environment of detrimental magnetic fields in the immediate vicinity of the welding operation. The Hall-effect probe is connected through a detector circuit and a control circuit to the power supply for the electromagnet. Upon detection of the magnitude and direction of the effect of a detrimental magnetic field by the Hall-effect probe, appropriate adjustment is made of the power supplied to the electromagnet through the detector and control circuits, enabling the electromagnet to nullify the effect of the detrimental field on the preselected magnetic environment.

Fume extracting welding gun nozzle

Abstract: A welding gun nozzle including a first passageway through which welding wire may be fed into a weld and a second passageway through which shielding gas may be directed over the weld to protect the molten metal from contamination. The nozzle also includes a fume extracting passageway having an inlet orifice so located with respect to the outlet end of the nozzle that the fumes are drawn into the nozzle from a region laterally outward from the nozzle, and thus from an area removed from the weld, so the shielding gas is relatively unaffected by the operation of the fume extracting feature of the invention.

Device for uniting parallel and oppositely disposed wall portions of a tube by transverse welding seams

Abstract: The invention relates to article packaging machines and particularly to a device for connecting oppositely disposed wall portions of a lengthwise moving flexible tube containing rather high articles in axially spaced relation by transverse welding seams which are produced by continuously moving welding dies between each article in the tube. In addition to these welding dies the device is provided with two symmetric gusset folders which enter transversely into the space between the dies and the adjacent ends of the spaced articles during the time interval at which the dies press the oppositely disposed wall portions together for engaging the tube material and folding it smoothly against the end faces of the articles during the continuous lengthwise movement of the tube; in fact, the gusset folders do not only move transversely back and forth at right angles to the tube, but also move lengthwise with the tube.

Lithium containing welding electrode

Abstract: An electrode for electric arc welding in air and a method of using same. The electrode contains lithium compounds and agents to reduce these compounds to elemental lithium in the welding arc. Lithium is added to the welding rods preferably in the form of lithium fluoride and/or lithium silicates, while the reducing agents are preferably calcium, aluminum and magnesium, and are preferably added in the form of intermetallic compounds of calcium and aluminum, and calcium and magnesium. A quench material to de-stabilize or quench the lithium-containing arc plasma and give it a higher voltage gradient may also be used. Satisfactory quench ingredients include carbohydrates; sugar (sucrose), because of its ready availability and lost cost, is preferred.

Microstructural effects of heat treatment on the bond interface of explosively welded metals

Abstract: The microstructure and composition of the interface of nickel-to-copper, copper-to-steel, and tantalum-to-steel explosion welds which had been subjected to heat treatments between 500° and 1100°C was investigated by electron microscopy and electron probe microanalysis. The results confirmed that explosive welding establishes continuous and practically diffusionless metallurgical bonds. Diffusion induced by heat treatment causes characteristic microstructural changes along the bond zone which depend on the type of binary phase diagram to which the specimen belongs. The diffusion penetration in nickel explosively welded to copper is noticeably more extensive than in the similar electroplated couple. In all three metal pairs the diffusion rate varies cyclically along the weld interface. These latter effects appear to be related to the unique concentration and distribution of lattice defects characterizing explosively bonded metals.

Apparatus for damming pipe ends for welding

Abstract: A method and apparatus for welding together a pair of pipe ends. The method comprises providing a water soluble dam at each pipe end, inserting an inert gas into the ends between the dams, welding the ends together and passing a fluid containing water through the pipe to dissolve the dam.

Means for welding pipe sections

Abstract: A method and means of welding adjacent pipe sections in tandem relation at the installation site for the pipe line. An internal clamping apparatus simultaneously engages the inner periphery of adjacent pipe ends in such a manner as to apply radially outward pressure thereto for reforming the ends into substantially identical circular configurations, regardless of any existing deformation in the pipe. The two reformed pipe ends are securely retained in an abutting position by the clamping means during the entire welding operation. An external welding apparatus is secured around the outer periphery of the pipe in the proximity of the abutting pipe ends for providing a circumferential weld at the pipe joint. The welding apparatus includes a pair of independently movable carriages, with each carriage being provided with a plurality of welding heads for performing simultaneous but sequential welding operations. One of the carriages moves from a position corresponding to 0* through a distance of substantially 180* around the circumference of the pipe while the other of the carriages moves around the circumference first from a position of 270* to 180* and then from 360* back to 270* whereby the welding operation is performed in a balanced manner around the entire circumference of the pipe joint. The welding heads of each carriage perform simultaneous welding operations, with the welding head performing a first welding operation at the pipe joint, and the next succeeding welding head tracking the movement of the first welding head and performing a second welding operation at substantially the exact optimum time interval between the two welding steps to assure an efficient welding of the joint. It is preferable to provide three of the welding heads on each carriage. However, it has also been found that two welding heads on each carriage perform an efficient total welding operation. Subsequent to the welding of the pipe joint, the internal clamping apparatus and external welding apparatus may be moved longitudinally along the pipe line to the position of the next pipe joint to be welded, and the entire operation may be repeated.