Showing papers on "Arc welding published in 1977"

Device for teaching and evaluating a person's skill as a welder

Abstract: An apparatus for simulating an arc welding operation, for training welders and for evaluating a welder's performance including a target representing a simulated weld to be made, mechanism for imparting predetermined motion to the target, a simulated welding tool including a simulated welding rod and a holder for the rod, the rod having a free end with an element adjacent thereto having properties capable of being sensed magnetically, a magnetic sensor assembly located adjacent to the target for movement therewith and including members capable of responding to the presence of the magnetic field produced by the magnetic element on the rod for producing responses depending upon the position of the simulated welding rod relative thereto and the distance of the rod therefrom, the magnetic sensor assembly including angularly related pairs of opposed sensor members arranged to produce responses to represent the position of the simulated welding rod relative thereto in two different angularly related directions, each of the sensor members being capable of producing a response when in the field of the magnetic element, an electric circuit connected to the sensor members of the aforesaid pairs including circuitry for combining the responses produced by selected ones of the sensor members to produce electric signals representative of the position of the free end of the rod relative to the sensor members and representative of the distance between the rod and the sensor assembly, and a sensor element located on the rod holder, the sensor element being constructed and positioned to respond to the angular orientation of the simulated welding rod relative to the target. The present apparatus also includes an electric circuit for producing audible responses and/or visual indications to simulate an arcing condition and to indicate and record errors that an operator makes in following the target during a simulated welding operation.

Processes and materials of manufacture

Abstract: 1. The Manufacturing Engineer. 2. Classification and Fabricating Characteristics of Metal and Composites. 3. Numerical Control (NC) and Computer Steps to the Automated Factory. 4. Metrology and Quality Control. 5. Metal Cutting Theory and Practice. 6. Turning and Related Operations. 7. Holemaking and Related Operations. 8. Milling, Broaching, and Sawing. 9. Grinding and Related Abrasive-Finishing Processes. 10. Metal Casting Processes. 11. Plastics and Adhesives. 12. Power Metallurgy. 13. Metal Stamping and Forming. 14. Bulk Deformation of Metals. 15. Welding Principles and Arc Welding. 16. Gas Welding, Brazing, Cutting Systems, and Weld Testing. 17. Resistance, Specialized, and Solid State Welding. 18. Non Traditional Machining. 19. Process Planning.

Welding Process Technology

Abstract: Preface 1. Properties and classification of welding processes 2. The welding arc 3. Flux-shielded arc welding 4. Gas-shielded arc welding 5. Unshielded and short-time arc welding 6. Resistance welding 7. Thermochemical welding 8. Radiant-energy welding 9. Solid-phase welding 10. The selection of welding processes 11. Automatic welding 12. Economic considerations Index.

Flux cored wire for welding Ni-Cr-Fe alloys

Abstract: A self-shielding, flux cored arc welding electrode for joining Ni-Cr-Fe alloys and overlaying dissimilar metals. The wire has a nickel-chromium containing alloy sheath and a flux core containing special proportions of carbonates, fluorides, metal oxides, and powdered metals. Sound welds can be prepared without the use of a supplemental inert shielding gas. Welded joints provide essentially the same properties as those of the Ni-Cr-Fe base alloy.

Remote control portable wirefeed arc welding system

Abstract: A remote control unit for closing a normally open contactor in response to closing of a normally open gun switch in a portable wirefeed arc welding system having a power source including the contactor, a portable wirefeed unit, a welding gun, a ground cable interconnecting the power source and the work, an electrode power cable interconnecting the power source and the wirefeed unit and gun, and control leads interconnecting the wirefeed unit with the work and the gun; wherein a capacitor in the control unit is operable to place an override current on the ground and electrode power cables in response to closing of the gun switch, and sensing means comprising a sense relay are operable in response to such override current to effect closing of a normally open cycle hold delay relay and the contactor. The cycle hold delay relay, in turn, closes a fourth or rearming delay relay which opens the circuit to the sense relay. So long as welding current is drawn, the first control relay remains closed to hold the cycle hold delay relay closed. An interruption of welding current for two seconds causes the cycle hold delay relay to time out to open the rearming delay relay and the contactor.

Method of arc-welding

Abstract: In underwater arc welding in a chamber filled with gas a consumable flux cored arc welding wire is fed to a welding torch and an arc is struck between the wire and the work to be welded so as to effect transfer of weld metal from the wire to the work. The arc welding wire contains at least one strong deoxidizer selected from the group consisting of magnesium, aluminium, zirconium, titanium, barium, lithium and calcium. A shielding gas is fed to the torch and emerges therefrom as an annular curtain of gas which shields the arc. The shielding gas also helps stabilize the arc from the effects of underwater pressure. The shielding gas comprises at least one oxygen-containing gas selected from oxygen and carbon dioxide.

Clamping apparatus for welding circumferential articles

Abstract: Apparatus for rapid and automatic welding of joints which interconnect sections of pipe, and in particular oil or gas transmission pipe. The system includes at least one torch transport assembly which simultaneously moves a plural number of welding torches along a path parallel to the pipe joint being welded. The torch transport assembly includes track segments which surround circumferential portions of the pipe joint, with a welding torch carrier and multiple torches being independently movable along each track segment. The torch transport assembly is mounted on a support apparatus which is rigidly clamped to the pipe sections during welding, and which permits the torch transport assembly to be rapidly positioned in rough alignment with a pipe joint. The torch transport assembly and selected operating parameters of each welding torch are adjusted to accurately position each torch with respect to the pipe joint, and to repeatably provide programmed welding parameters resulting in a uniform pipe joint weld. The present system is disclosed in the context of hot-wire gas-tungsten arc welding torches, and in the operating environment of out-of-position joint welding.

Method for tube welding

Abstract: A method for butt welding a pair of vertically disposed tubular members having a wall thickness of more than 12 mm in end-to-end relationship by multi-pass shielded arc welding with a consumable electrode, comprising the steps of preparing the opposed edges of the tubular members by forming a root face the width of which being in the range of 0.5 mm to 3.0 mm and beveling the edges adjacent to the root face to a bevel angle in the range of 40° to 50°, coaxially aligning said tubular members so that the gap between the root faces is not larger than 1.5 mm, performing a root pass by continuously feeding an electrode having a diameter not larger than about 1.0 mm into the groove between the prepared edges supplying a shielding gas consisting of 0-40% carbon dioxide and the balance argon, energizing an arc between the electrode and the root face alternately changing the voltage supplied to the arc between a low value and a high value, adjusting the low voltage to produce a droplet metal transfer during short circuit periods, adjusting the high voltage to produce a spray metal transfer, adjusting the welding speed and the electrode feeding speed to deposit metal in the groove in the range of 0.15 to 0.35 grams per mm length of the pass, and successively depositing overlapping passes for filling the groove.

Method and apparatus for tig welding

Abstract: A method for TIG welding by using a plurality of nonconsumable electrodes extending frm the tip of a TIG welding torch and one filler wire fed through a space between the electrodes, each electrode being independently supplied with power. A molten pool is formed by melting both the base metal to be welded and the filler wire by means of arcs generated between respective electrodes and the base metal. Melting of the base metal is mainly controlled by the arc produced by one of the plurality of electrodes while melting of the filler wire is mainly controlled by the arc generated by the other electrode.

Method of and device for arc welding

Abstract: A method of plasma MIG welding in which an arc is maintained between a workpiece and a welding wire in a thermally ionized gas (auxiliary plasma) which is generated by an electric gas-discharge between two non-consumable electrodes; neither the welding wire nor the workpiece acts as a single electrode for generating the thermally ionized gas.

Method of arc welding under water

Abstract: In a method of arc welding under water or at superatmospheric pressure (or both) the weld is made in a chamber containing a gaseous atmosphere. The weld metal is deposited from flux-cored welding wire whose core contains strong deoxidant(s) such as aluminium, magnesium, titanium, zirconium, lithium and calcium. A shielding gas containing a selected proportion of oxygen or oxygen-containing gas but consisting mainly of an inert gas such as argon or helium is employed to surround the arc. The shielding gas is constituted by the atmosphere in the chamber.

Combination welding torch for shielded inert gas or electric arc welding

Abstract: Welding torch comprises a combination collet body which functions interchangeably for electric arc welding, of the open arc type using a consumable electrode, or for inert gas shielded welding using a non-consumable electrode The collet body has a screw-threaded collar at one end which is screwed into the welding head At the other end, it has a slitted or splined chuck The slightly enlarged central body portion between the collar and the chuck includes a plurality of gas vents For open arc welding, a consumable electrode, interposed into the chuck, is secured in place by a constricting metal adapter sleeve which also serves to close the gas vents For inert gas shielded welding, the consumable electrode and the metal adapter are replaced by a nonconsumable electrode and a ceramic shield open at one end The open vents permit inert gas to escape under the ceramic shield and surround the nonconsumable electrode during the welding process

Method and apparatus for position and oscillation control in automatic electric welding

Abstract: An apparatus for welding the adjoining ends of annular work members, such as lengths of pipe, employing an arc nozzle for melting and depositing metal in the gap between said adjoining ends. A drive motor coupled to the nozzle drives the nozzle laterally back and forth across the gap while the current that flows in said arc is integrated to generate a physical representation of magnitude of the integral. Means are provided to arrest the motor each time the magnitude reaches a predetermined threshold value, and to reverse the direction of travel of the motor.

Method of connecting metallic parts by means of arc fusion welding

Abstract: A method of 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 jointed 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.

A review of minor element effects on the welding arc and weld penetration

Abstract: A critical review of all the available literature pertaining to welding arc and weld penetration has been undertaken The review revealed several studies which indicate that the intentional or unintentional addition of small amounts of halides to the base material significantly improves weld penetration The presence of oxygen in the weld materials has been reported to have both positive and negative effects on the depth and shape of the weld Various other elements present in the base material have been alluded to as a means of changing the penetration characteristics of the GTAW process In particular, aluminum addition to the arc or excessive aluminum in the base material has been observed to produce a flared arc at the anode surface In many cases these changes are accompanied by variations in the arc voltage which, if properly interpreted can act as a warning signal for potential problems The general conclusion of all the published reports stress the need for additional systematic study and further research into this problem area in order to understand the causes and effects that have been noted experimentally An attempt has therefore been made to provide some beginning and rationale for understanding how the properties of minor elements can affect the factors which influence weld penetration In particular, the factors discussed relate to changes in the work function of both the anode and cathode surfaces, the arc voltage and arc configuration, in addition to surface tension effects of the weld puddle and arc stability In order to provide much-needed additional experimental data to this problem area, a spectroscopic analysis of a typical GTAW arc was undertaken and a simple test initiated to determine the "penetration" qualities of various heats of EN 82 filler material The results and conclusions of these studies are reviewed

Method of multi-pass narrow groove arc welding

Abstract: A method of multi-pass arc welding with a consumable electrode in a protective atmosphere for welding heavy-gauge metal with narrow grooving, wherein, according to the invention the initial electrode extension is adjusted to be greater than the depth of grooving of welded joint, a current supply conductor which supports the consumable electrode passing therethrough is placed in a permanent position above the welded joint, and the welding is conducted with the length of extension of consumable electrode decreasing upon each pass, the voltage applied to the current supply conductor, rate of feed of the consumable electrode and welding speed being reduced with the decrease in the length of extension of the consumable electrode.

Welding, a steel suitable for use therein

Abstract: A steel which contains up to 0.15% carbon, 0.5 to 1.5% manganese, 0.03 to 0.10% silicon, less than 0.2% molybdenum, up to 0.05 aluminum, 0.03 to 0.05% titanium and 0.002 to 0.008% boron is particularly suitable as a welding consumable, for example as an electrode for the submerged arc welding of high strength micro-alloyed structural steels. Especially when used with a basic flux, welds can be produced showing excellent notch toughness characteristics.

Control system for arc welding machine - has probe following line of weld with transducers to control path of electrode

Abstract: An arc welding machine has a bed plate (17) with a sliding worktable (14) driven through a screw (28) by a motor(30). TWo vertical columns (20) support a cross beam (34) which carries the welding head (40). The welding head can move along the cross beam by another lead screw (36) driven by another motor (38). The welding head can pivot about its vertical axis and its angular position is measured by a transducer (43) mounted in the support (42). As the stylus (46) follows the line of the required weld between the workpieces (16), the transducers transmits signals to a circuit which controls the motors and so ensure that the welding electrode follows the correct path.

Non-consumable tungsten electrode for arc welding in inert gas - where only the electrode tip contains addn. increasing electron emission

Abstract: The electrode is made of refractory material, esp. tungsten, and consists of a shaft free from addns. (a) employed to increase electron emission; on one or both ends of the shaft is a tip attached by welding; and the tip has a higher electron emission than the shaft. The pref. shaft is made of tungsten, whereas the tip is pref. tungsten contg. an addn. (a), esp. 0.2-10 wt. % ThO2. The shaft and the tip are pref. made separately by powder metallurgy, and the tip is possibly shaped by hot working. The shaft and tip are then joined by either electron beam welding, or pulsed arc welding with brief application of pressure. The tip may then be ground. Simple mfr. of an electrode contg. addn. (a) only in the tip, and with long working lift is TIG or plasma welding is provided.

Welding torch oscillation apparatus

Abstract: Apparatus for rapid and automatic welding of joints which interconnect sections of pipe, and in particular oil or gas transmission pipe. The system includes at least one torch transport assembly which simultaneously moves a plural number of welding torches along a path parallel to the pipe joint being welded. The torch transport assembly includes track segments which surround circumferential portions of the pipe joint, with a welding torch carrier and multiple torches being independently movable along each track segment. The torch transport assembly is mounted on a support apparatus which is rigidly clamped to the pipe sections during welding, and which permits the torch transport assembly to be rapidly positioned in rough alignment with a pipe joint. The torch transport assembly and selected operating parameters of each welding torch are adjusted to accurately position each torch with respect to the pipe joint, and to repeatably provide programmed welding parameters resulting in a uniform pipe joint weld. The present system is disclosed in the context of hot-wire gas-tungsten arc welding torches, and in the operating environment of out-of-position joint welding.

Arrangement in electrical welding apparatus

Abstract: An a.c. operated arc welding apparatus comprises a controlled frequency converter which substantially increases the frequency of the alternating current and the output of which is connected to the welding electrodes via a transformer and a rectifier. The connection between the rectifier and the welding electrodes includes a shunt capacitance having an impedance low enough to attenuate the alternating current components of the welding current to a level acceptable from the acoustic aspect, the said connection further comprising means for preventing the capacitor from adversely affecting the rectifier and frequency converter and also comprising a choke arranged between the capacitor and the electrodes to prevent the capacitor from adversely affecting the welding properties.

Preliminarily treating method for diffusion welding of stainless steel, aluminum or aluminum alloy

Abstract: PURPOSE: To enable the effective diffusion welding, by electrolyzing in the electrolytic solution using the welding material consisting of stainless steel or Al(alloy) as the anode, removing the oxide and nitride coating on the surface and then immediately plating a specified metal respectively using the welding material as the cathode. COPYRIGHT: (C)1978,JPO&Japio

Automatic arc welding method for high efficiency multielectrodes of low temperature high toughness steel

Abstract: PURPOSE: To weld the thick steel plate, having a superior low temperature toughness, with a high efficiency, by forming the root pass bead with HIG welding using the wire, restricted C, P, S by multielectrodes automatic welding and carrying out submerged arc welding by heat input quantity of the wire, having a specific composition. COPYRIGHT: (C)1978,JPO&Japio

Multiple welding head system for fabricating pipe

Abstract: A pipe is fabricated from rolls of flat metal plate by continuously moving the plate into a pipe-forming station which shapes the flat plate into a pipe having a longitudinal seam therealong. A plate arc welding machine welds consecutive plates to each other thereby maintaining continuity of plate movement. Equal sections of the longitudinal seam are consecutively welded in a leapfrogging manner using two welding units movably positioned on the opposite sides of the moving pipe. The welding units alternatingly weld alternate and overlapping sections of the longitudinal seam. The welding operations are carried out without interference with the continuous movement of the pipe.

Controller for DC arc welding generators

Abstract: The controller automatically and remotely controls the stopping and running of an internal combustion engine coupled to a DC generator that supplies DC power to the welding cables of an arc welding machine. The engine has a starter, an ignition, and an intake manifold. A vacuum-actuated switching means is coupled to the intake manifold and is responsive to the vacuum produced therein. A switching circuit is coupled to and is controlled by the vacuum-actuated switching means. A starter and an ignition are coupled to the switching circuit. A timer having a predetermined timing interval is coupled to the switching circuit, to the welding circuit, and to the ignition.

Arc welding electrode position control - by deviating arc magnetically and measuring the arc length

Abstract: The position of an electrode holder is adjusted w.r.t. a joint between two workpieces which are to be welded together. At least two characteristic quantities of the arc parameters are derived from the arco burning between the electrode holder and different regions of the sides of the joint. The characteristic quantities are mathematically coordinated and the result is compared with a control value which corresponds to the desired position of the electrode holder, and a control margin, which corresponds to the difference between the result of the calculation and the control value is used to position the electrode holder. The welding arc itself acts as a sensor determining the relative position between the electrode holder and the joint.

Apparatus and method for inert gas arc welding

Abstract: An arc welding torch terminates in a gas cup open at one end through which an electrode projects. Inert gas is introduced under pressure at the other end of the gas cup and flows past and through a gas diffuser disposed in said gas cup. The diffuser is spaced from the inner wall of the gas cup, and a portion of the gas flows axially parallel to the central axis of the gas cup. The diffuser has a set of passageways to form and direct columns of gas in an outward direction, and another set of passageways to form and direct columns of gas in an inward direction. The diffuser is axially and angularly adjustable to vary the pattern of gas discharge with relation to the arc and to control the contour of the weld bead. BACKGROUND OF THE INVENTION The present invention relates to inert-gas arc welding, and more particularly, to a method and apparatus for applying a shielding gas in the welding operation. In the conventional arc welding processes, such as either the TIG (tungsten inert-gas type) or the MIG (consumable inert gas type), the heat generated by the electrical arc is utilized to reduce the metal material to be joined to a molten state to effect fusion between the parts to be joined. Most metals in a molten state will react with atmospheric gases, usually resulting in an unstable arc and a poor weld. In one known process for stabilizing the arc, when welding aluminum plate or the like, a shielding gas, which is normally argon or helium, is utilized to surround the arc and exclude atmospheric gases from the weld area and prevent oxidation of the molten metal which will ultimately form the weld. In addition, the gas provides a low resistance path for the arc and the gas ions provide a cleaning action by bombardment of the metal surfaces to be welded. Various problems have existed in the application and utilization of the shielding gas. For example, optimum cleaning action was not achieved. Weld bead contours were not as controllable as desired. A very close torch cup to work distance had to be maintained to prevent disruption of the gas pattern by external forces. Moreover, the efficiency of the gas consumption was less than desired. In addition, when welding in vertical position, the weld metal flow and solidification patterns were less than optimum. An example of a plasma generating torch is shown in U.S. Pat. No. 3,604,889 but in such patent the gas, instead of being directed in columns, is cone-shaped and is concentrated into a stream which penetrates the arc externally of the torch. Moreover, there is not axial or angular adjustment of the stream. SUMMARY OF THE INVENTION A gas cup substantially closed at one end and open at the other has an electrode disposed therein. An inert gas entrance means is disposed remote from the open end. A diffuser in accordance with the present invention is mounted to direct the gas in a predetermined manner relative to the arc and the pieces to be welded, in accordance with the present invention. The diffuser is adapted to form and direct columns of the inert gas in an outwardly flaring direction from the central axis of the electrode and to form and direct other columns of the inert gas towards the longitudinal central axis of the electrode. The diffuser also coacts with the body of the torch to form a cylindrical column of gas which surrounds the directed columns of gas to provide a protective shield for the directed columns. The diffuser is adjustable axially and/or angularly with reference to the electrode, whereby the gas columns may be varied for the most efficient operation. By the foregoing arrangement, improved cleaning patterns provided by the cleaning action of gas ions bombarding the metal surface has been achieved, and improved weld bead contours have been obtained. The torch cup to work distance is not as critical, and the disruption of the gas pattern by external forces is reduced. The gas consumption for a given torch nozzle size and set of welding parameters has also been reduced by the improved utilization of the gas to provide optimum effect. Moreover, improved weld metal flow and solidification patterns have been obtained when welding in the vertical position.