Abstract: A welding torch having two relatively movable assemblies of elements and an annular chamber therebetween. One of the assemblies is provided with a scraping device to strip strongly adhering metal particles from the lower portion of the inert gas chamber of the torch, and a pneumatic system is operative to then remove these as well as the remaining weakly adhering particles from the entire length of the chamber.

Abstract: An inert gas is supplied in a conduit system at a pressure high enough to provide a desired shielding gas volume at each and all arc welding sites spread over a substantial work area and each welder is responsible for the performance of a lightweight, readily portable, security protected, fixed pressure output regulator of high accuracy preferably having a pressure gauge and two independent visible output flow meters and flow valves easily adjusted separately to provide proper shielding at the front and back of a weld simultaneously, but independently, under the personal control of each welder at each welding site with excellent mobility regardless of floor elevation, for an acceptable and individualized responsibility for each certified weld performed.

Abstract: A fume extracting device (10) for an arc welding apparatus (12) effectively removes fumes from the leading and trailing portions of the arc welding zone (82) while maintaining transverse compactness. The fume extracting device (10) includes first and second body portions (30) individually having an internal fume collecting chamber (50), a plurality of fume inlet passages (54), and a fume exhaust passage (48) and is so constructed that the body portions (30) are maintained in a preselected spaced apart relationship to each other and to the central axis (14) of the welding apparatus (12). Advantageously, first and second gas shielding devices (64) can be individually connected to the one of the body portions (30).

Abstract: An arc welding torch having electrode gripping means is located rearward in the torch head and remote from the welding operation which occurs in a carefully formed, unerratic, cooling atmosphere of shielding gas enveloping the electrode and flowing in collimated fashion.

Abstract: An improved purge unit is provided for establishing an enclosed zone around a weld area for retaining an inert gas. The purge unit is particularly advantageous when welding a branch pipe or pipe connection to a main pipe or header. The purge unit has a cone-shaped member which is inserted into an opening in the header through the branch pipe or connection and is then expanded to establish the enclosed zone around the inside of the weld area. An inert gas is then supplied through the purge unit into the zone and the cone-shaped member is subsequently collapsed and withdrawn after the weld is complete. An expandable tube is employed to expand the cone-shaped member and has a rod extending therethrough and connected to the member to provide greater stability for the purge unit.

Abstract: A transferred type plasma torch comprises a body containing and rigidly interconnecting; a bushing having an internal constricted surface, a collet attachment mounted in the bushing, an electrode mounted in the collet attachment, a nozzle tip disposed coaxially of the electrode at the tip, and a centrally bored end cap screwed in the end of the bushing and having an internal countersunk surface. The collet attachment is composed of a cylindrical collet having a spherical flanged portion and a collet chuck having a spherical flanged end portion and mounted in the collet, the spherical flanged portion of the collet being received in the internal constricted surface of the bushing, the spherical flanged end portion of the collet chuck being received in the internal countersunk surface of the end cap. The spherical flanged portion of the collet and the spherical flanged end portion of the collet chuck are so designed that they have the same center of curvature.

Abstract: A ferritic stainless steel weld wire for forming a ferritic weld deposit free of martensite under a gas blanket containing a reactive component. The weld wire contains in weight percent about______________________________________ w/o ______________________________________ Carbon 0.04 maximum Manganese 1.0 maximum Silicon 1.0 maximum Phosphorous 0.045 maximum Sulfur 0.045 maximum Chromium 10.50-12.00 Titanium 0.30-0.75 Nitrogen 0.02 maximum Nickel 0.25 maximum Molybdenum 0.50 maximum Copper 0.50 maximum Cobalt 0.25 maximum ______________________________________and the balance iron. The ratio of the weight percent titanium to the sum of the weight percent carbon plus the weight percent nitrogen is at least 12.5:1 in the weld wire and at least 8:1 in the weld deposit.

Abstract: In longitudinally seam-welding a pipe-blank for welded steel pipe from the inside along a groove by the GMA welding process which comprises using direct electric current supplied to a plurality of consumable electrodes in tandem through at least one cable as the welding current, at least two even-numbered consumable electrodes are used, half of said consumable electrodes being connected to said direct current so as to be positive in polarity and the remaining half of said consumable electrodes being connected to said direct current so as to be negative in polarity, to enable lines of magnetic force produced by said direct electric current for welding flowing through said at least one cable introduced into said pipe-blank to cancel each other, thereby preventing magnetization of said pipe-blank and the resulting magnetic arc blow of the welding arc.

Abstract: Plasma-MIG welding in which a thermally ionizable inert gas stream is flowed through a nozzle non-consumable electrode having a central aperture and a surrounding annular aperture toward a workpiece and is thereby split into a central gas column enveloped by an annular gas shield. A consumable electrode is fed through the central gas column toward the workpiece, with the establishment of a MIG-arc therebetween. A plasma arc is spontaneously established by means of the MIG-arc between the nozzle non-consumable electrode and the workpiece.

Abstract: A welding apparatus including a nozzle assembly having a contact extension and a contact tip for guiding a consumable welding wire into a tube hole. The consumable welding wire is guided into the tube hole and an electric current is passed to the wire to produce an arc between the tip of the wire and the sidewall of the tube hole, melting the wire and supplying filler weld to the hole. The nozzle assembly has a gas nozzle; and, during the welding process, an inert gas is delivered into the tube hole through the gas nozzle.

Abstract: A continuous cored electrode includes a sheath which encloses a core formed of a granular material of the following composition, in percent by weight:______________________________________ feldspar from 1.8 to 10.4 sodium fluosilicate from 1.6 to 10.0 ferromanganese from 13.0 to 20.0 ferrosilicon from 0.6 to 1.6 reduced titanium concentrate from 58 to 83. ______________________________________The proposed cored electrode is well suited for use in the CO.sub.2 welding of low-carbon and low-alloy steels.

Abstract: Arc heater apparatus using total alternating current characterized by a pair of axially spaced cylindrical electrodes forming a narrow gap therebetween and connected to a first alternating current power source to produce an arc in the gap, each electrode having magnetic coil means for producing a rotating magnetic field at the arcing surface of the electrodes to rotate the arc, and the magnetic coil means being connected to a second alternating current power source which has an arc current zero aligned with that of the first alternating current power source.

Abstract: A flux-cored electrode intended for arc welding of steels in carbon dioxide s characterized in having a casing of a low-carbon steel filled with a powder flux containing (in weight percent):calcined magnesite: 4-8,feldspar: 6-9,calcium fluoride: 4-5.5,titanium dioxide: 14-20,ferromanganese: 6-10,ferrosilicon: 1.5-3,iron powder: the rest.The flux-cored electrode is practicable if used in semi-automatic and automatic welding of metal structures from structural low-carbon and low-alloy steels and from steels of improved strength. The flux-cored electrode with the above chemical composition of the flux is conducive to reduced separation of fluoride gases harmful to welders, the high welding characteristics of the electrode remaining intact.

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.

Abstract: Chemically resistant steels for containers are butt welded by using an automatic welding process. The electrode is oscillated over the whole width of the seam and is kept to a maximum thickness of 1 mm.

Abstract: In plasma arc welding apparatus of a type including a plasma arc torch which is movable relative to a welding stock and transforms orifice gas into a plasma jet stream directed toward the welding stock, the flow of orifice gas is regulated by a throttle valve, a motor adjusting the valve under the influence of adjustable timing means capable of selectively increasing, decreasing and maintaining at a steady state the flow of orifice gas toward the torch. In order to accurately regulate the throttling valve, the timing means preferably includes an adjustable cam assembly driven by the motor along with the valve and operatively coupled with the motor by one or more switches capable of regulating motor operation in order to achieve desired flow control by the valve.

Abstract: A tool for underwater welding comprises an open-mouthed bell with an axially extending electrode inside, part of that electrode being surrounded by a tube supplying gas under pressure from a pumping station floating on the surface. Another tube linking the bell with that pumping station supplies water under pressure to an annular chamber open toward an array of fluid-guiding blades carried by the bell. In one embodiment, the bell is rotatably mounted and carries the blades on its outer surface, being set in rotation by the oncoming flow; in another embodiment, the bell is stationary and the blades are arranged on its inner surface whereby the water swirls in a film along that surface. In either case the circulating water forms a vortex that passes along the bell periphery and around the bell mouth which is slightly spaced from the workpiece to be welded, the resulting centrifugal forces preventing the entry of surrounding water into the bell whereby a gaseous atmosphere is maintained in its interior.

Abstract: The disclosure of the present application relates to an improved method of open-arc welding. According to the present method, the outer shield of a double-shield welding system consists of a stream of gas formed in a shield concentric with the inner shield. This method is distinguished by the fact that atmospheric air may be used as the outer shield gas because the outer-shield velocity is so regulated and so positioned as to prevent the air from being drawn into the weld area, the outer shield gas velocity nearly approximating the inner shield gas velocity.

Abstract: A welding gun has a separable nozzle embodying longitudinally curved inner and outer concentric sleeves, and fore and aft-mounted bodies to which the opposed ends of the concentric sleeves are brazed to define an annular gas manifold between the sleeves into which gas feeds through the aft-mounted body. The aft-mounted body detachably seats within a tubular handle and it contains a bore through which the consumable wire electrode feeds to the central bore of the inner sleeve. The fore-mounted body provides for connection of an adapter by which a current pickup tube is fixed to the curved nozzle in line with its inner sleeve to receive the wire electrode. Said fore-mounted body is ported at spaced intervals for discharge of gas from the manifold through the adapter and about the current pickup tube when assembled thereto.

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.

Abstract: A welding torch assembly including a torch base, and a torch body which can be rapidly removed from the torch base and replaced without the use of tools, and without separately disconnecting welding current, coolant, or shielding gas lines.

Abstract: An electrode method for welding thin steel sheets using the MIG and/or MAG welding process is made from a copper-manganese alloy with 3-35% Mn, 0-15% Ni, 0.02-0.7% Si and the remainder copper.

Abstract: Workpieces to be joined by welding are held in juxtaposition to provide a joint location to which welding wire is to be fed. The welding wire is fed to the joint location from a passage in a welding wire feeder that is guided for movement relative to the workpieces and the joint location. As the welding wire feeder is moved relative to the joint location, welding wire passes from a groove in the feeder through an arcuate passage directed toward the joint location. During welding the feeder is moved relative to the workpieces along the weld line. The welding wire is melted at the joint location by being heated, such as by connecting a workpiece and the welding wire feeder to an electric circuit for producing a welding arc between the welding wire and the workpieces at the joint location.

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.

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.

Abstract: To control the plasma arc in accordance with the present invention, the pressure change characteristics or curve in a torch is determined from the moment a plasma forming gas is delivered thereto until this plasma forming gas reaches the pressure in the supply manifold. Such a measurement is done for each selected cutting condition characterized by a constant flow rate of the plasma forming gas. The arc supply current is then fed in two stages: at first by a jump to a current amounting to approximately half the cutting current for a selected condition and then by gradually increasing the current in compliance with the pressure change characteristics or curve until the cutting current value is attained.

Abstract: A method and apparatus for welding workpieces wherein the workpieces are defined by a structure having a plurality of areas with joined and bonded locations with at least one of the areas being different in depth than the depth of its adjacent area. At least one group of welding heads is provided in a predetermined spacial arrangement. When the welding heads are activated, they operate to join and bond the workpieces at certain joined and bonded locations. A carriage is provided to move the workpieces under the welding heads. Limit switches and a control circuit are provided for stopping the workpieces under the welding heads so that a first zone on the workpieces, which includes portions of more than one of the areas of different depths are under the welding heads. Means are also provided for lowering the welding heads until they come into contact with and exert pressure on the workpieces adjacent the location to be welded in the areas different in depth in the first zone.

Abstract: The disclosure is directed to apparatus for and a method of joining a plurality of laminations of electric steel, which are individually core-plated for electrical insulation purposes, to form a laminate structure used in the manufacture of electrical machinery. Joinder of the laminations is accomplished with the laminations in face-to-face relation and arc welding a bead transverse to the stacked lamination edges. To avoid porosity in the weld bead, the arc welding process uses microwire having a diameter of no greater than about 0.050 inches in a moving welding head that maintains the microwire in close proximity to the welding surface. The operating voltage of the arc welding apparatus is controlled to produce an operating welding current of no more than about 170 amperes. The effect of using microwire of such size under such an operating current prevents overheating and degradation of the coreplate, and results in a proper deposition of a strong, non-porous weld bead.

Abstract: A torch for welding, cutting or heating comprises a torch head having at least one outlet nozzle, a torch housing spaced from the torch head, connecting means connecting the torch head with the torch housing and provided with passages therethrough to be flown through by a cooling medium, and elongated hermetically sealed heat-transmitting means extending through the connecting means for automatically transporting heat from a heat receiving zone adjacent the torch head to a heat releasing zone adjacent the torch housing for cooling the torch head, in which the heat releasing zone is cooled by the cooling medium passing through the aforementioned passages.

Abstract: A metal inert gas welding torch having a wire guide assembly threadably secured at one end to a torch body and a collet nut assembly threadably secured to the other end of the wire guide assembly. A spidered collet is mounted in the collet nut assembly and forms a plenum chamber with the wire guide assembly and collet nut. A contact tip is gripped by the spidered collet and extends into the plenum chamber whereby the shielding gas cools the contact tip prior to the distribution of such gas into a nozzle.

Abstract: An underwater pipeline is repaired by cutting away a defective section thereof and replacing the defective section with another length of pipe. The replacement is joined to the exposed ends of the pipeline by welded ball-and-socket joints. Those welds that it is necessary to perform under water are made in a gaseous environment created in a chamber having an open base through which water may be displaced by gas and at least one transparent side panel which is displaceable to form a gap in the side of the chamber. A diver may insert a welding gun or welding rod through this gap. The chamber has outer tubular flanges which receive the lengths of pipe extending through the chamber. Tubular members of flexible or elastomeric material are used to seal each flange to the length of pipe passing there through. Each tubular member of flexible or elastomeric material is positioned around the flange and length of pipe which it is to seal.

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 INVENTIONThe 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.

Abstract: Control means for a welder of the "tungsten-inert-gas" type which senses even momentary engagement of the workpiece by the torch to initiate gas flow. The welding region is initially purged by the gas. After a predetermined timed interval the output of the welding power source is elevated to a level sufficient to cause the striking of an arc.Gas flow is maintained during the welding operation and for a predetermined time interval after extinction of the arc is detected.Means are also provided for visually indicating gas flow and further for automatically preventing the striking of an arc when gas flow is exhausted.Means are provided so that the welder power supply may also be turned on automatically to eliminate the need for foot or hand-operated switches conventionally used to turn on the welder power supply.Sensing means are also provided to protect the torch from becoming accidentally "welded" to the workpiece.

Abstract: In a gas shielded arc welding method for a long seam of formed pipe and the like, an improved method of setting up a welding voltage-current such that incomplete short circuiting transfer is performed with a high speed of more than at least 3m/min. and particularly, 5m/min. or more, without requiring stopping of the arc at short circuiting intervals.

Abstract: A metal spraying device of the kind in which two wires are fed along convergent guide ducts, and an electric potential is established between the wires, so that an electric arc is produced between the terminal ends of the wires. A jet of air is blown across the arc, removing metal from the ends of the wires in the form of minute droplets, the jet of air being directed against a workpiece to be sprayed with a metallic coating. The metal spraying device comprises a head made of insulating material (e.g. ceramics material), the head being provided with passages forming the guide ducts for the wires and for the jet of air. In this manner, the wires may be guided more accurately to the arcing zone, and turbulence in the jet of air may be minimized, producing an overall improvement in the quality of the spray which may be achieved.

Abstract: The extent of shielding function of an arc atmosphere is measured by the concentration of nitrogen oxide in the arc atmosphere. The concentration of nitrogen oxide in the arc atmosphere is measured by a nitrogen oxide measuring device. The measured value is indicated by an indicator. When the measured value exceeds a predetermined reference value, an alarm device is operated or a welding operation is stopped. Either a supply of shielding gas which forms an arc atmosphere is controlled, or a flow of fume is controlled through a fume exhaust device, as a function of the measured value.

Abstract: A device for plasma-MIG welding comprising a welding torch provided with a non-consumable electrode and a supply of a welding wire, the non-consumable electrode being connected to a first power supply source having a drooping voltage characteristic and the welding wire being connected to a second power supply source having a constant voltage characteristic, the first power supply source being connected in series with the second power supply source, thereby improving the stability of the plasma arc.

Abstract: A metallic powder and flux-cored arc-welding or hard-surfacing electrode having improved metal deposition rate for gas-shielded arc-welding or hard-surfacing processes is disclosed wherein about 24 to about 35% of the total weight of the electrode is contributed by the core and the core is characterized by a relatively low flux content and high metallic powder content in the order of about 80% or greater, which metallic powder is preferably powdered iron.

Abstract: A method of large current gas shielded arc welding wherein the welding is accomplished at high speed by a single electrode or tandem sequence electrodes in an atmosphere of a mixed shielding gas comprising essentially of an inert gas with an addition of less than 30% of carbon dioxide gas or less than 5% of oxygen and supplied at an overall flow rate of 50 to 200 l/min by using large diameter solid wire consumable electrodes of low alloy steel material with a diameter of 3.0 to 6.4 mm .phi. under the following conditions: welding speed 300 to 1500 mm/min; welding current, 600 to 1500 amp; and arc voltage, 23 to 36 volts. With this method, the welding of steel can be accomplished at high speeds with a reduced heat input and an improved efficiency and it is particularly well suited for the welding of open tubes for very low temperature line pipe which must retain a high degree of toughness at very low temperatures.

Abstract: A method and apparatus for horizontal fillet welding of steel plates, particularly coated or painted steel plates, in which two spaced apart welding wires are directed toward the line of intersection of a vertical steel plate and a horizontal steel plate to be welded together so that the centerline defined between the two wires intersects with such line of intersection. The wires are alternately fed toward the line of intersection in such a manner that one of the wires is fed to the vertical plate at a first predetermined rate and the other of the wires is fed to the horizontal plate at a second predetermined rate which is greater than the first rate.

Abstract: A compact, flexible, lightweight welding gun is provided, including a single outer tubular casing substantially containing all the weld gun components. Concentric disposition of annular fume evacuating passageways between the outer tubular casing and component electrical transmitter elements insulates the external surfaces of the casing from the electrical heat sources within the gun, while cooling gases circulating in the gas passageways promote dissipation of accumulating heat. The improved cooling properties of the gun permit relatively higher levels of current and therefore increased speed of weld bead deposition, while the single conduit structure of the welding apparatus renders it more compact, flexible and lightweight, as well as more maneuverable due to the relatively clean exterior of the gun.

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.

Abstract: Welding apparatus comprising a power and gas transmission cable having coupling means including normally closed valve means for controlling passage of gas from said cable, a first welding torch including a gas passage and having first torch coupling means adapted for connection to said cable coupling means, said torch coupling means including means for opening said valve means with said first torch and cable coupling means connected, and a second welding torch having second torch coupling means adapted for connection to said cable coupling means, said second torch coupling means adapted to maintain said valve means closed with said second torch and cable coupling means connected.

Abstract: A three-phase arc heater system characterized by two axially spaced, sustantially cylindrical electrodes forming a first intermediate gap, a third electrode forming a second intermediate gap upstream of the first gap, means for channeling gas to the first and second gap, and a three-phase delta-connected power source having a ground conductor connected to the downstream electrode.

Abstract: The arc heater of this invention is characterized by a pair of axially spaced substantially cylindrical electrodes which form a narrow gap between adjacent ends thereof. The gap communicates between a peripheral plenum chamber and the arc chamber formed by the electrodes, and the gap is included inwardly and downwardly toward the outlet end of the arc chamber in order to prevent solid particles from entering and clogging the gap as the particles travel through the arc chamber. The arc heater also includes a third cylindrical electrode disposed at the inlet end of the arc chamber.

Abstract: A housing chamber for use in underwater arc welding is constructed in the form of a portable hollow cylinder open at one end and having a side opening in which is movably mounted a welding gun for effecting a welding operation on a workpiece through the open end. The interior of the housing chamber is illuminated and a viewing plate slanted relative to the axis of the cylinder closes the other end. The chamber is provided with means for introducing gas under pressure to purge the chamber of water. An L-shaped vent tube adjacent the viewing facilitates purging the housing chamber of water. The vent tube is rotatably adjustable relative to the housing chamber to control the amount of gas discharged. A porous rubber gasket member is provided between the workpiece and the open end of the cylinder to permit escape of gas therethrough to facilitate relative movement between the cylinder and the workpiece.

Abstract: In a multiple electrode gas shielded arc welding method wherein a plurality of electrodes are arranged along the welding seam line of a piece of metal to be welded and the continuous gas shielded arc welding of the piece is accomplished simultaneously by the electrodes, the chemical composition of a mixed shielding gas fed to the electrodes is selected in such a manner that the chemical composition of the shielding gas fed to the leading electrode or electrode group differs relative to that fed to the trailing electrode or electrode group to have a different active gas volume ratio and in this way the chemical composition of the weld metal layers formed by the preceeding and following welding operations are homogenizing to ensure uniformity of the properties at every positions in the weld zone.

Abstract: A method and means for more efficiently stabilizing a plasma arc produced within a plasma producing device. Improved arc stabilization is achieved by dissipating the heat generated by the electrodes of the plasma producing device under controlled conditions. This is achieved, in one instance, by direct liquid cooling of the anode and concomitantly therewith indirect liquid cooling of the cathode. The latter is achieved by passage of a liquid coolant around a heat sink positioned in conductive relationship with the cathode.

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.

Abstract: A method of operating a plasma welding apparatus producing a plasma arc and having valve means arranged to control gas flow for the plasma arc and power supply means arranged to control welding current for the plasma arc, wherein the plasma arc current, gas flow to the plasma arc and the feed of a filler material to the arc are coordinated for producing a weld. The gas flow and welding current are maintained at a steady rate during the weld run. The gas flow is reduced at a constant rate to a minimum valve of about 30 % of the steady flow rate at the conclusion of the welding run and the welding current is subsequently reduced at a constant rate from the steady value of the welding current.