Showing papers on "Gas metal arc welding published in 1984"

Variable polarity plasma arc welding on the Space Shuttle external tank

Abstract: Variable polarity plasma arc (VPPA) techniques used at NASA's Marshall Space Flight Center for the fabrication of the Space Shuttle External Tank are presentedd. The high plasma arc jet velocities of 300-2000 m/s are produced by heating the plasma gas as it passes through a constraining orifice, with the plasma arc torch becoming a miniature jet engine. As compared to the GTA jet, the VPPA has the following advantages: (1) less sensitive to contamination, (2) a more symmetrical fusion zone, and (3) greater joint penetration. The VPPA welding system is computerized, operating with a microprocessor, to set welding variables in accordance with set points inputs, including the manipulator and wire feeder, as well as torch control and power supply. Some other VPPA welding technique advantages are: reduction in weld repair costs by elimination of porosity; reduction of joint preparation costs through elimination of the need to scrape or file faying surfaces; reduction in depeaking costs; eventual reduction of the 100 percent-X-ray inspection requirements. The paper includes a series of schematic and block diagrams.

Method and apparatus for arc welding

Abstract: An arc welding process is provided with a preheating step in which a consumable wire electrode is heated prior to insertion into the electrode stick-out region. This is accomplished by the circulation of current from a preheating power supply through a segment of the wire. Both gas-metal and gas-tungsten arc welding processes are disclosed, along with apparatus used in these processes.

Tubular welding electrode

Abstract: A formulation for the flux in a cored-type electric arc welding electrode which produces high impact value welds while welding vertically up or overhead and at greater melt-off rates than heretofore. The major flux ingredients are lithium oxide, iron oxide, silicon dioxide, lithium carbonate, magnesium and aluminum metal powders, all in a carefully balanced formula to give excellent operator appeal and excellent slag removal.

Components for gas metal arc welding gun

Abstract: A gas metal arc welding gun includes a power cable in which the power conductors are asymmetrically distributed in a crescent between a gas conduit and a sheath in order to improve flexibility of the power cable. The welding gun includes a head assembly which includes a head that defines an internal annular ridge between a contact tip and a free end of an electrode liner. This annular ridge serves as a stop for the contact tip, as a centering guide for the electrode liner, and as a shield to protect the electrode from welding spatter. The welding gun includes a two-piece handle which includes a tongue and aperture guide at one end, and an interlocking flange guide at the other end. The two guides restrict movement between the two housing parts to axial movement, and a snap ring locks the two housing parts in a desired assembled position.

Electric arc conversion process

Abstract: Electric arc conversion process in which C 1 -C 4 alkane is brought into contact with an electric arc and higher molecular weight carbonaceous material is brought into contact with the hot gas derived from the C 1 -C 4 hydrocarbon in the vicinity of the arc.

Short-circuit MIG welding

Abstract: A method and apparatus for short-circuit MIG welding is described. The apparatus comprises a power supply (1) electrically connected with electrode wire (2) and a workpiece (4) in use; and electrode wire feed means (8). Monitoring means (9) is provided for monitoring the ratio (M) of one of the mean and successive integral of the arc duration to the corresponding one of the mean and the successive integral of the short-circuit duration. The welding process can be monitored by monitoring the ratio (M).

Arc welding torch having integrated wire feed

Abstract: A compact gas tungsten arc welding torch, which may have an integral puddle view optical system, utilizes an inert gas supply line and coolant supply and return lines, one carrying current for the weld process. The torch body has passages for flow of cover gas from a connection tube to the gas nozzle. The gas supply hose additionally carries the filler wire for the weld process, which passes into the gas connection tube and out of the torch body to an integral wire feed guide tube that is alternatively inside or outside of the gas nozzle.

Laser welding method and apparatus

Abstract: A laser welding method and apparatus for welding stacked coated members (1. 2 1 in which voids in the welds are positively eliminated. A spacer (14) is disposed between the two members (1, 2) to be welded. This provides a path (16) for discharging gas formed by heating the coating matenal. The method and apparatus of the invention are useful for the laser welding of base members coated with metals having a lower melting point than the metal of the base, paints and oils. Preferably, the width of the gap is in a range of 0.1 mm to 0.5 mm.

Powder surface welding method

Abstract: A powder surface welding method using a plasma torch is disclosed, which uses a surfacing powder containing not less than 95% of particles having a particle size of -60 mesh to +250 mesh. This welding is carried out at a welding speed of not less than 3.8 mm/sec without weaving the plasma torch. Particularly, the distance L between the end of the plasma arc jetting nozzle in the plasma torch and the base material to be surfaced is regulated to be within a range of 0.5 Ds+6≦L≦Ds+8 , and the offset angle θ of the axial center of the plasma torch with respect to the rotational center of the base material is regulated to be within a range of 7°≦0≦20°.

Pulsed arc welding apparatus

Abstract: A method of pulsed arc welding and an apparatus for carrying out the method, employ welding current pulses having an amplitude greater than the value of a background current. The arc voltage is sensed to provide a signal for controlling the frequency of the welding current pulses to counteract variations in electrode wire feed speed or spacing of the electrode from the workpiece.

Method for preventing the discoloration of areas around indentation in spot welding

Abstract: A method for preventing discoloration of the area around an indentation in spot welding is provided in which the weld zone and its surrounding area are masked with a non-oxidizing gas such as argon gas, helium gas, nitrogen gas or a mixture of argon gas and carbon dioxide gas from ambient atmospheric air and spot welding is carried out in the atmosphere of the non-oxidizing gas to prevent the discoloration from occurring at the weld zone of a metal sheet under the influence of heat during spot welding.

Arc welding apparatus

Abstract: A method and apparatus are provided for removing spatter from a torch of a gas shielded arc welding apparatus. After a series of welding operations are completed, pressurized air mixed with a small amount of oil is injected through a passage defined between a member supplying a welding electrode and a gas nozzle. This oil emitted adheres to the surface of the electrode supply member and the gas nozzle, thereby generating an oil film thereon. The pressurized air removes any spatter on the apparatus and the oil film prevents any further spatter from adhering to the surface.

Gas-metal-arc welding process

Abstract: In a gas-metal-arc welding process, a stable plasma formation is produced by a shielding gas mixture whose flow is focused to steadily maintain the plasma formation in central alignment with the arc. Thus, the plasma energy and arc energy are combined and concentrated to yield a higher, more stable welding heat. The process is of the type that utilizes a welding gun having a consumable wire electrode that is continuously advanced towards the weld deposit as its end melts and is transferred to the weld deposit. The gas is a mixture of major proportions of each of argon and helium and minor proportions of each of carbon dioxide and oxygen, which produces a stable, approximately dome-like plasma formation in the arc gap between the electrode melting end and the weld deposit. A portion of the gas that flows through the gun nozzle and around the electrode, is directed at an acute angle towards the electrode axis within the arc gap, and is focused, by adjusting the gap length, upon a spot on the electrode axis at the weld deposit, so that it impinges upon and pressures the plasma formation inwardly into axial alignment with the arc, producing an intense heat zone in the gap.

The Nitrogen Absorption of Stainless Steel Weld Metal by Gas Tungsten Arc Welding

Abstract: Using an arc atmosphere controlling chamber, effects of the welding conditions and atmosphere on the nitrogen content of the stainless steel weld metal by gas tungsten arc welding were investigated in comparison with those on the iron weld metal. The results are as follows:(1) The temperatures of stainless steel and iron molten pools were measured as about 1530°C and 1630°C, respectively.(2) The nitrogen content of stainless steel weld metal decreased with increasing the welding current, as well as that of iron weld metal.(3) The nitrogen content of stainless steel weld metal hardly depended on the arc length, as well as that of iron weld metal.(4) The nitrogen content of stainless steel weld metal increased with increasing the travel speed, while that of iron weld metal hardly depended on the travel speed.(5) The nitrogen content of stainless steel weld metal increased with the nitrogen partial pressure at low nitrogen partial pressure region, and was constant at the nitrogen partial pressure region above 0.2 atm in N2-Ar gas mixture atmosphere, as well as that of iron weld metal.(6) The nitrogen absorption by stainless steel weld metal was discussed with equilibrium data.

Consumable electrode type pulse arc welding method

Abstract: PURPOSE:To shift molten metal in the state of small lump without stopping a large quantity of molten metals at the tip of a wire, and to stabilize the arc preventing generation of spatter by changing speed of feeding of the welding wire in synchronization with the period of pulse current. CONSTITUTION:In consumable electrode type pulse arc welding, the welding wire 12 is melted by a welding arc 21 and forms molten metal 12a. The molten metal 12a is accumulated at the tip of the wire 12, and at the same time, the wire 12 is fed toward an object to be welded 14. At this time its current value increases. From this state, the feeding speed of the wire 12 is reversed. That is, the wire 12 is shifted in the direction going away from the object to be welded 14, and the molten metal 12a is separated and shifted forcibly by inertia. As force of inertia due to change of feeding speed of the wire is given to the molten metal 12a in addition to pinch effect of pulse peak current, sure separation and shifting are made from the state of small lump. Accordingly, a beautiful bead free from welding defect can be obtained.

Consumable electrode type gas shielded arc welding method

Abstract: PURPOSE:To execute defectless and satisfactory welding with high efficiency by using a specific laser beam as a preceding heat source and defocusing specifically the spot diameter of a laser beam. CONSTITUTION:The CO2 laser beam or YAG laser beam 11 is used as the preceding heat source in the stage of executing consumable electrode type gas shielded arc welding. Said beam 11 is used after the spot diameter DY thereof is defocused to 2mm.<=DY<=25mm. and materials to be welded are subjected to MIG welding while said materials are uniformly heated over a wide range by the out-of-focus beam.

Arc welding filter

Abstract: A device intended to remove pollutants from the gases surrounding an arc welding operation comprising principally a blower adapted to draw the gases away from the welding operation The gases are drawn into an inlet located near the work area through a hose having coils adapted to absorb heat from the gases A filter using both magnetic and mechanical means is used to filter the pollutants from the gases before discharging into the ambient atmosphere

Hot wire tig welding method

Abstract: PURPOSE:To make a hot wire TIG arc welding highly efficient by varying periodically in the prescribed frequencies a mean arc current and by controlling the wire heating power source so as to become the heating electric power corresponding to the feeding speed by detecting the heating electric power of the wire. CONSTITUTION:TIG are welding is performed by outputting a pulse current Iap from a power source 4 with setting of a base current Iab on a power source 19 and by switching continuously in >=10Hz the output current of the power source 4 to an arc 5 and wire 6 by GTO14, 15. In this case a mean arc current Im is periodically varied in <=4Hz and the heating power of the wire 6 is detected by detector 18. The wire electric welding time TW is determined then so as to become the heating power corresponding to the feeding speed of the wire 6 and the power source 4 is controlled by a heating control device 16. The increase in the arc current during LOW period and wire melting rate is thus enabled and the high efficient TIG arc welding having good operability is realized.

Mig welding wire for high-tension steel

Abstract: PURPOSE:To provide an MIG welding wire which is to be used for welding of high tension steels and yields a weld metal having excellent low-temp. toughness by controlling strictly the kind and content of the elements constituting the wire. CONSTITUTION:A welding wire consists, by weight, of class, etc.), the weld metal having excellent toughness and satisfying substantially strength even at a low temp. of about -100 deg.C is obtd.

Electric arc conversion process and apparatus

Abstract: Electric arc conversion process in which C1-C4 alkane is brought into contact with an electric arc and higher molecular weight carbonaceous material is brought into contact with the hot gas derived from the Ci-C. hydrocarbon in the vicinity of the arc.

Measuring proximity of metal to an arc welding torch

Abstract: @ Apparatus for measuring the distance between an electric welding torch and a workpiece especially useful with an aluminum workpiece A nonconsumable electrode is mounted adjacent the consumable electrode of the welding torch with the nonconsumable electrode electrically isolated from the consumable electrode A power supply connected to the consumable electrode provides an auxiliary arc and developes a consumable electrode voltage proportional to the distance between the torch and the workpiece The consumable electrode voltage can be used to develop signals which guide the torch along a groove in the workpiece

Pulse arc welding

Abstract: PURPOSE:To perform stable welding that generates little spatter in consumable electrode type gas shielded arc welding by using an arc current pulse current consisting of main pulse current and sub-pulse current. CONSTITUTION:When a base metal to be welded 18 by generating an arc 17 between a consumable welding wire 16 in welding torch 15 and a base metal to be welded 16 under the presence of shielding gas, welding current is set to pulse current constituted of current values 6, 7, 8. In this case, current generating devices 3, 4, 5 are switched by a time 2 to be times 9, 10, 11, 12 to obtain pulse current having main pulse 13 and sub-pulse 14 of smaller current than the main pulse. A droplet is formed at the end of the welding wire by the main pulse current 13, and the droplet is separated from the tip of the wire 16 to a molten pool by the sub-pulse 14. Thus, stable consumable electrode type gas ghielded welding that generates little spatter can be performed.

Welding system for TIG welding

Abstract: TIG welding with an electronic operating scrape ignition circuit, which by lifting the welding electrode (6) is activated by an idle voltage control (7) in such a way that the welding current quickly is raised above the basic current, thereby an electric welding arc is established without using high voltage. Because of the low welding current initially, under 10 amp, the system is very suited for welding thin plates.

Welding method taking laser with mig

Abstract: PURPOSE:To obtain penetration or welding speed equal to that of a large output laser without increasing the laser output by matching the focus of a laser beam with the point near the bottom of the crater in a base metal melted by MIG welding and performing welding with deep penetration. CONSTITUTION:One end of an arc welding machine is connected to a base metal 3 and the other end to a MIG torch 10, and an arc is generated between a wire 1 and the metal 3. When a crater is produced on the metal 3, the laser beam 4 is positioned so that the beam 4 focuses at the point near the bottom of the crater. The beam 4 and a MIG torch 10 are united to one body so as to provide the max. penetration in said position whereby the welding is accomplished. Or the groove angle of the metal 3 is taken at <=50 deg. and the laser 4 is focused near the root in the groove so that the MIG welding is performed before the molten metal solidifies. The penetration in the root part is made thorough by the above- mentioned method and the deep penetration is obtd.

Longitudinal seam welding of uoe steel pipe

Abstract: PURPOSE:To perform satisfactory longitudinal seam welding of a UOE steel pipe by welding the outside surface side of a solid or clad steel blank pipe consisting of a stainless steel, nickel alloy, etc. subjected to O forming by a combination of plasma welding and other kind of welding and the inside surface side by TIG welding. CONSTITUTION:The joint part of a solid or clad steel blank pipe consisting of a stainless steel, nickel alloy or non-ferrous metal, etc. subjected to U and O forming is joined by a combination of plasma, SAW or MIG welding, etc. and TIG welding on the outside surface side to increase the welding speed and to prevent various kinds of brittleness and crack. The inside surface side is joined by TIG welding or a combination of MIG welding and TIG welding to flatten the bead and to prevent defect. The defect-free longitudinal seam welding of the UOE steel pipe is executed with high efficiency by such combined welding.

Submerged arc welding process

Abstract: In a submerged arc multiple wire welding system, only one or two of the welding wires used are over or microalloyed wires. The other wires are commercially available unalloyed or low-alloyed solid wires. The process produces a weld metal which has unexpectedly high toughness values, and can be performed more economically. This multiple wire welding system is used in single or multiple-pass welding operations.

Cr-mo wire for mig welding

Abstract: PURPOSE:To obtain good low temp. toughness while suppressing temper embrittleness phenomenon and preventing generation of weld defects such as blowholes by specifying the composion component of a wire for MIG welding. CONSTITUTION:A Cr-Mo wire for MIG welding by using a gaseous mixture composed of Ar-O2, Ar-CO2, etc. as shielding gas is constituted by contg. essentially 0.04-0.10% C, 0.25-0.55% Si, 0.85-1.20% Mn, 2.00-3.50% Cr, 0.90-1.20% Mo, 0.040-0.100% Ti, 0.012-0.032% N, and 0.005-0.020% O, in which Mn/Si (by weight) is >=2.2 and 100N/Cr (by weight) is 0.5-1.4 and consisting of the balance iron and unavoidable impurities.