Showing papers on "Shielding gas published in 1977"

Laser beam welding

Abstract: Laser beam welding apparatus comprising a body with a passage through which the laser beam is directed and focused to a position outside the body closely adjacent to a terminal portion of the passage. A second passage opens into the first to direct a transverse jet of shielding gas to sweep away the plasma formed during welding through an aperture in the opposite wall of the first passage. Since the welding zone is virtually enclosed by the body the incidence of air entrainment by the transverse jet of shielding gas is minimized.

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.

Automatic pipe welding apparatus and method

Abstract: A TIG pipe welding method which employs two sets of machine guide surfaces on the pipe ends. First radially inner guide surfaces cooperate with a sensor coupled to the welding torch to continuously monitor the arc gap between the welding electrode and the weld puddle as the welding electrode moves around the circumference of the pipe. The second set of radially outer surfaces cooperate with a welding carriage to guide the carriage and welding modules around the pipe joint. The carriage is constructed to provide a sealed welding chamber surrounding the electrode. An additional flow of shielding gas is provided around the torch electrode of a TIG or hot wire TIG welding module to augment the normal gas shield. The augmented shield provides a gas flow in opposition to pressurized air flowing through the welding chamber to prevent exposure of the weld nugget to the pressurized air flow being maintained in the welding chamber while permitting the pressure forces to be transmitted through this shield to the weld nugget, creating a "puddle pushing" effect. The transfer of forces through the gas shield, while preventing contaminating air from entering the weld zone itself, provides a positive force for pushing the molten weld puddle through the joint to the interior surfaces of the joined pipe ends. The pressurized air further flows outwardly between the seals of the welding carriage and the pipe surfaces to create an air cushion between the pipes and the carriage. An internal weld backup and pipe alignment ring is also provided.

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.

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 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.

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

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.

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

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.

Shielding gas generator for heat treatment furnaces - is cracker with tubular housing with catalyst held in furnace chamber

Abstract: Shielding gas generator is used in furnace for chemical and metallurgical treatment during heat treatment. This generator is situated directly within the furnace. No disturbing reactions take place and processes such as gas carburisation bright hardening and combined carburising and nitriding can be carried out at temp. between 500-1000 degrees. A heated cracking unit which is lagged against furnace, is placed directly into furnace chamber. The cracker has enclosing tubular heater. hollow space is formed between tubes and uniform gas and air mixture is formed in hollow space. this space has also inert layer and catalytic layers. The shielding gas generated enters furnace chamber through bottom of the cracking unit.

Welding method by direct current gas shielded arc

Abstract: PURPOSE: To form the weld zone having a superior mechanical property with a high welding efficiency without producing a bad bead by deoxidation product, by carrying out direct current gas shielded arc welding with shielding gas, core wire and more than two electrodes applied different welding current. CONSTITUTION: On occasion of using two electrodes, the distance between the preceding electrode 1 and the succeeding electrode 2 is kept apart more than 100mm. Shielding gas mixed more than 30% of CO 2 gas or less than 5% of O 2 gas with inactive gas, such pure Ar gas or He gas etc., is used in the ratio of 15W100l/ min. at the electrode 1 and 0.6W1.6mmϕ of the core wire 12 and 100W500A of welding current, are used. Shilelding gas mixed 7.5W50% of CO 2 or 1W10% of O 2 gas with pure Ar gas or He gas, is used in the ratio more than 50kg/min. at the electrode 2. 3W6.4mmϕ of large core wire is used for the core wire 22 and 600W1500A of welding current is used. The deoxidation product 8 is not moved in fron of arc and the weld zne 7 havig a superior impact value, is able to obtain. COPYRIGHT: (C)1979,JPO&Japio

Welding method for ferritic stainless steel

Abstract: PURPOSE: To weld ferritic stainless steel efficiently to produce weld joint of excellent mechanical property by utilization of metallurgical reaction of CO 2 and molten metal through mixing CO 2 of specific quantity with inactive shield gas for nonconsumable electrode type arc welding machine. COPYRIGHT: (C)1978,JPO&Japio

Welding torch and supporting apparatus

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.

Welding method for electron beam of high carbon steel material

Abstract: PURPOSE: To prevent the occurrence of crack at welding part, by carrying out electron beam welding, butting overlay welding part, after carrying out overlay welding of steel, being carbon content less than 0.20%, on welding surface, at the time of welding high carbon steel, containing carbon more than 3.30%. COPYRIGHT: (C)1978,JPO&Japio

Method of hard surfacing a metal object

Abstract: A hard surface on reactive metal such as a titanium member is weld deposited in an inert gas atmosphere using a welding rod tubing made of the same metal as the member and filled with tungsten carbide particles.

Metal body made of stacked metal plates - is brazed as clamped assembly in vacuum or shielding gas furnace

Abstract: The metal body such as a heat exchanger is made of stacked metal plates. These plates are shaped to give the body cross section. Etched metal plates are clamped into a stacked unit by a clamping mechanism. Sufficient quantity of brazing material is deposited on the surfaces to be joined. Flux may also be added if necessary. The stack is subsequently heated to the melting temperature of the brazing material and after the spaces are filled with brazing material the assembly is cooled. The stack arrangement can be heated under vacuum or in the shielding gas atmosphere. A cold melting crucible can be used.

Inert gas welding piston fed with electrode wire - has vibrating gas nozzle preventing deposition of weld spray on or in pistol

Abstract: The pistol is fitted with a vibrator, so that the wall of the gas nozzle is subjected to periodic or continuous vibration. The vibrator is pref. operated electromagnetically, hydraulically, pneumatically, or by an electric motor. A pref. pistol uses an electric motor to rotates a cam, which oscillates two spring strips with bend end knocking against the nozzle. In one design, the gas nozzle is fixed on the head of the pistol by a PTFE bush. In welding using a consumable electrode wire, weld spray is deposited on the front end and the bore of the gas nozzle, blocking gas flow which causes weld defects; welding must be stopped while the nozzle is cleaned. The invention eliminates such problems.

Submerged arc welding process for nickel containing steel

Abstract: This invention provides a process involving submerged arc welding for nickel containing steel such as steel containing 3.5 weight percent of nickel. The process uses a bond type flux of specific composition to suppress the oxygen content in the weld metal. Further, the process utilizes a cored welding wire including a core material of specific composition. As the result, it is possible to obtain a weld metal of high impact-resistance at low temperatures such as minus 100° C.

Resistance welding of metals with high electrical and thermal conductivity

Abstract: A simple device for welding metals with high electrical and thermal conductivity is described. The use of the device, which was adapted from a commercially available carbon deposition unit, for welding 0.0127 and 0.0507‐cm‐diam Ag, Au, and Pt wires is discussed.

Continuous anode mode for high-speed tungsten/inert-gas arc welding

Abstract: It has been reported recently that, for an arc in air between a stationary thoriated tungsten rod cathode and two copper anode cylinders rotating together end to end, the arc current, when above a certain critical value, divides and flows from a stationary bell-shaped arc column into continuous `diffuse? electron-collecting areas on the two anodes, instead of into separate anode spots with an arc column jumping from one to another. Because of possible advances in high-speed welding techniques, to which this continuous anode mode may lead, this work has now been extended to stainless-steel anodes in a shielding flow of argon. It is shown that this same mode does exist both for these conditons, and also when small percentages of hydrogen are added to the shielding gas, whereby useful increases in workpiece melting are achieved for the same arc current.