Showing papers on "Gas metal arc welding published in 1973"

Heat flow to the workpiece from a TIG welding arc

Abstract: Less than half of the heat generated in a TIG welding arc (typically 1600 W at 16 V, 100 A) is transferred to the workpiece (anode). Convection, conduction and radiation from the gas occur over the whole of the arc region, but they represent relatively minor contributions to the total heat balance. The principal anode heating and cooling mechanisms involve electron and space-charge effects at the surface. These electron effects are evident in the workfunction (typically 45 V) which is dominant, the electron thermal energy transfer (1 V) and the anode fall (2 V), and they are concentrated in the restricted anode current spot so they may be considered as a localized heat source. Evaporation is most intense from the anode spot region and carries away some heat. However, most of the vapour condenses on the cooler, outer regions of the anode surface covered by the arc. In this way, heat is redistributed and diffused over a wider area. Vaporization effects explain the differences between previous measurements with cooled copper anodes (in which 80% of the arc power is transferred to the metal) and ones with practical, molten-steel welds (less than 50% heat transfer).

Disposable resistance welding electrode

Abstract: This invention relates to a new type of resistance welding composite electrode which is disposable utilizing an inexpensive metal or alloy having good electrical and thermal conductivity as a holder, and a metal or alloy also having good electrical and thermal conductivity and in addition good strength at resistance welding operating temperatures for the insert tip.

Starting and stabilizing apparatus for a gas-tungsten arc welding system

Abstract: A method and apparatus for starting and stabilizing an arc in the gas-tungsten arc welding system and the like. A plasma flame extending from the tungsten electrode to the work is established by ionizing a portion of the flow of inert gas used for shielding. The gas is ionized by means of an auxiliary arc that is struck between the tungsten electrode and a second metal component of the torch acting as a second electrode. The resulting plasma flame provides a conductive path for starting and stabilizing the main arc struck between the tungsten electrode and the work.

Deep narrow gap welding torch

Abstract: A welding torch adapted for welding deep narrow gaps wherein shielding gas diffusers fit inside the welding groove, a plastic liner is placed deep inside the torch so electric contact between the filler wire and contact tube is close to the exit, and a zirconia oxide insulation prevents torch contact with the gap walls.

Deep penetration welding using lasers

Abstract: A TEMoo mode laser beam is focused on a material to be welded to a power density sufficiently high, depending upon the material of the workpiece, so that deep penetration welding occurs producing a weld having a depth-to-width ratio substantially greater than 1. To initiate the weld, the incident power density and power must be sufficiently high to overcome the relatively high reflectivity of metallic workpieces. With relative movement between the workpiece and the beam, seam welding can be performed, as well as lap welding and blind welding.

Welding torch for underwater welding

Abstract: The invention relates to a welding torch for welding underwater and to a method of underwater welding using the welding torch. A high speed stream of water is directed from a nozzle on the welding torch obliquely onto a member or members to be welded to form a flared-out curtain of water. Gas is injected into the volume enclosed by the curtain of water to create a gaseous atmosphere and welding is carried out in the gaseous atmosphere.

Method for welding iron steel and nonferrous alloy

Abstract: In welding iron, steel, and nonferrous alloys, the wire feed is changed periodically and in synchronism with periodic changes of the electric welding current to establish a previously defined relation between the welding current value and the arc length. The welding current is varied between one producing a spray transfer arc and a current just maintaining the arc.

Grain refinement control in tig arc welding

Abstract: A method for controlling grain size and weld puddle agitation in a tungsten electrode inert gas welding system to produce fine, even grain size and distribution is disclosed In the method the frequency of DC welding voltage pulses supplied to the welding electrode is varied over a preselected frequency range and the arc gas voltage is monitored At some frequency in the preselected range the arc gas voltage will pass through a maximum By maintaining the operating frequency of the system at this value, maximum weld puddle agitation and fine grain structure are produced

Electrode for vertical-up open arc welding using molding shoes

Abstract: A cored-type welding electrode for vertical-up welding using molding shoes to hold the molten metal in position, using an open arc which does not require an externally-supplied shielding gas and which permits very high linear welding speeds. The core materials include a metal fluosilicate capable of breaking down in the heat of the arc to produce: a gas in sufficient volume to shield the arc from the atmosphere and a slag forming ingredient; and, other slag forming ingredients including the metal oxides and the alkali metal fluorides in a critical volume such that the total slag forming ingredients do not exceed six percent of the total electrode weight and the oxides are present in quantities at least greater than the fluorides. The self-shielded electrode further permits the use of active deoxidizers in quantities of under 0.5 percent.

Tungsten inert gas arc striking device

Abstract: A tungsten inert gas arc striking device for welding stainless steels and nonferrous metals, e.g., aluminum is provided, in which when striking an arc or restriking the arc, the charge stored in a capacitor is momentarily discharged through a discharge switch and a coupling coil to produce a kick voltage and this kick voltage is then superimposed on a welding current to effect the arc striking or restriking. Thus, welds of high quality can be produced and the occurrence of radio interferences can also be eliminated.

Vertical welding of heavy aluminum alloy plates

Abstract: A system for welding large aluminum alloy plates in a single vertical pass by the gas metal-arc (GMA) process wherein the technique comprises spacing square butt edges of the plates about three-fourths inch to form the welding gap; oscillating between defined dwell limits a welding electrode across the gap at comparatively high rate to deposit thin layers of weld metal, and confining the weld metal by dams having facing surfaces of molded high-density electrographitic material machined to high finish respectively. The dams together with the welding head are moved vertically upward at a smooth, uniform rate to preclude any objectionable jerking movement of the facing surfaces.

The Non-Stationary Metal Vapour Arc

Abstract: Abstract The motion is depicted as a sequence of steps of a finite residence time. The spot motion affects essentially only the energy characteristics Te which in comparison to the stationary characteristics Tes are shifted to smaller values. Hereby the critical currents I0, I1 are raised in comparison to the corresponding stationary limits I0s, I1s. Particularly attractive are the phenomena found in connection with the dependence of the spot velocity ʋ on the spot current I. If the spot velocity increases with the spot current stronger than ʋ ∞ I1/2 then the E-diagram reveals the existence of an upper limit lu for the spot current. This result can be used to explain qualitatively the experimentally observed phenomena of "spot multiplicity" and “spot extinction”. Quantitative conclusions are obstructed by the lack of knowledge about the velocity dependence on the spot current, ʋ(I). Experimental and theoretical studies to provide a better understanding of the physical background and the analytical laws describing the motion of the cathode spots are urgently needed.

Method of plasma-MIG-welding

Abstract: A method of plasma-MIG-welding in which welding is carried out with the electrode and the welding wire connected to the positive terminal; by varying the current in the welding wire, a variation of the character of the MIG-arc and of the way of material transfer are obtained; at low current in the welding wire, a MIG-arc with a contracted cylindrical shape and a concentrated material transfer is obtained; at high current a rotating MIG-arc and a controlled, spread material transfer are obtained.

Submerged arc welding process for very low-temperature steel and welded product

Abstract: A submerged arc welding process forming a welded steel joint consisting of said steel pieces joined by weld metal having superior impact resistance at low temperatures, said weld metal consisting essentially of up to 0.1% carbon, less than 0.4% silicon, between 1.2% and 1.7% manganese, between 0.08% and 0.5% molybdenum, between 0.02% and 0.05% titanium, between 0.0012% and 0.004% boron, up to 4% nickel, and less than 0.045% oxygen. The process utilizes specified low-temperature steel base metal which is to be welded; specified welding electrodes; and a flux.

Process for out-of-position welding

Abstract: This invention concerns automatic and semi-automatic welding by means of an electric arc under a protective atmosphere of a gas, using a continuous metallic tubular flux core-type electrode with a particular composition of the core. The fluxing ingredients produce a slag of unusually high viscosity at, and just below, welding temperatures.

Welding method and materials

Abstract: Methods and materials for submerged arc welding for obtaining a high toughness welded metal containing titanium and boron by using a flux cored wire composed of a steel sheath and a core containing titanium and boron with the addition of a metal fluoride.

Method of making self-centering pulley using mig welding

Abstract: A method and apparatus for depositing a stream of molten material upon the surface of a generally cylindrical pulley structure to form spirally tending ribbing thereon The preferred apparatus includes a device for rotating the pulley, a MIG welding device, suitable mechanisms for moving the welding head along the axis of the pulley, and means for varying the feed rate of the welding wire to the welding head as the head is moved along the length of the pulley whereby the height of the ribbing above the pulley surface varies over the length of the pulley

Electrode and flux combination for submerged arc welding

Abstract: In order to apply the submerged arc method of welding to a medium-carbon, Ni-Cr-Mo-V steel, and obtain a weld deposit which can be heat treated to provide a yield strength of 160-180 ksi along with a reduction in area of at least 25 percent and an impact resistance of at least 15 ft/lbs. at -40*F, an electrode wire having no more than 0.04 percent of silicon is utilized with a neutral welding flux having a residual percentage of manganese and from 1.5-3.0 percent of silicon to insure the proper deoxidation of the molten electrode. The flux also includes about 0.30 percent carbon for replacing that portion thereof lost from the electrode wire during the formation of the weld deposit.

Method of welding metals under water

Abstract: The underwater welding of metal surfaces using a plasma arc, wherein the plasma arc, plasma gas and weld part are sealed with a layer of water glass.

Fusion braid weld

Abstract: Means for joining braided copper leads or terminals to aluminum bus bars or tap straps. The means provides for clamping the braided copper member to the aluminum, preferably by means of a copper heat sink. Then the edges or overlapped areas of the copper and aluminum are fusion welded by a gas metal arc welding process with automatic aluminum wire feed. In a modified version a copper alloy wire is hand fed to the joint together with the aluminum filler wire from the welding gun.

Weld rod containing manganese

Abstract: A cored wire welding electrode for welding cast iron having an outer sheath made of nickel or a nickel-iron alloy and a powedered core composition containing copresent metallic magnesium and graphite and slag-forming ingredients along with special amounts of manganese. The electrode is particularly useful for open arc welding wherein a high strength weld deposit is required.

Process of welding a high tension steel

Abstract: A process of welding a high tension steel comprising welding said high tension steel by the Metal-arc-Inert-Gas welding method with an electrode by which a metastable austenitic steel weld metal is obtained and, thereafter, subjecting said welded high tension steel to (1) a sub-zero cooling to transform the austenitic steel into martensitic steel and (2) an aging treatment at a temperature and for a period of time sufficient to improve the tensile strength and yield strength of the product.

Plasma Arc Welding for Thick Plate (Report 1)

Abstract: This study was conducted as a preliminary research for further development of some plasma arc welding methods for thick plate above 10 mm.The large plasma torch and the control equipment designed to be proof against up to 1000 A with straight polarity connection have been fabricated especially for this study in our laboratory. With the ues of these equipments a series of experiments was carried out on the arc characteristics, welding conditions and welding sound.Conclusions obtained are summarized as follows:1) Thermal efficiency of plasma arc is in range of 53-60% and its heat losses to cathode, nozzle, shield cover and the other parts are 2, 20, 9-11 and 7-11% respectively at 500 A arc current.2) The Va-I (arc voltage vs. arc current), Va-Qp (arc voltage vs. plasma gas flow rate), and Va-la (arc voltage vs. arc length) characteristics of plasma arc at 300-500 A have been obtained as linear relationships whose slopes are in range of 0.02-0.05 V/A, 0.4-0.6 V/l/min and 0.4-0.6 V/mm respectively.3) The optimum welding conditions for plasma arc welding of 6, 8 and 10 mm thick mild steel plates have been evaluated in connection with welding speed, welding current, and arc constricting wall length of nozzle.4) In plasma arc welding of 16 mm thick mild steel plates, weld beads were produced as burn through or incomplete penetration beads. When the plates were backed up with copper plates, unstable plasma arc and sometimes series arcing occured and resulted in a defective bead.5) The frequency characteristic evaluation of plasma arc welding sound reveals that welding sound consists of mainly 300 Hz frequency as fundamental tone and its higher harmonics due to current pulsating (300 Hz frequency) in full wave rectification, and also that frequency characteristic is subject to the influence of welding condition mainly in above 2kHz frequency range.

Method of submerged arc welding of high tension steel workpieces

Abstract: Submerged arc welding of high tension steel workpieces by using bonded flux capable of generating at least 7 percent by weight of carbon dioxide gas during welding operation and producing slag with a basicity B L of not smaller than 1.0, in conjunction with a welding wire capable of providing alloying elements to weld metal, so as to produce weld metal having a high toughness and a high crack-resistivity.

Metal halide arc discharge lamp

Abstract: A high intensity arc discharge lamp comprises an arc tube having tungsten electrodes at each end and containing a fill including mercury, a starting gas and a metal in the form of metal halide. The tungsten electrode also contains a small quantity of said metal in solid solution with the tungsten.

Welding steel or aluminium plates - using metal-inert gas combined with hot wire process for heavy root passes

Abstract: The inert gas welding process is esp. for joining thick plates using seam-edge prepn. and a root welding pass followed by a filling pass or passes, the novelty being that the root pass is made by metal inert gas welding (MIG) using high current and the filling pass(es) made by the hot wire process. The hot wire pref. follows the MIG electrode wire, using the same molten bath, the MIG wire using a current density above 250 A/mm2 of the wire cross-section and a wire dia. of 0.8-2.4mm. Alternatively, an MIG wire of 1.6-4.0mm may be used with a current of 400-900 amps. The MIG- or the hot wire electrode may be cored. The term hot wire means the use of a wire carrying A;C. or D.C. where the wire is permanently immersed in the molten metal and melted primarily by resistance heating. Used for container and ship welding of steel plate 5-50mm thick, also Al plate. Avoids submerged arc-welding, tack welding, the use of a pad under the seam, and turning the plates over; the process can be applied by machine.