Abstract: A method of manufacturing a thick, high-strength steel pipe for low temperature service comprising the steps of forming into tubular shape a steel plate having a thickness of over 12 mm and a specific composition, of which the C.sub.eq value is adjusted to less than 0.50, when the Mn content is less than 1.0 % whereas the C.sub.eq value is adjusted to less than 0.45 when the Mn content is over 1.0 % and less than 2.0 %, and nextly of welding said tube form at high speeds and high efficiency by the process of single electrode or multiple electrode large-current gas-shielded arc welding with one pass per electrode on each side of the seam at a specific condition, each electrode preferably consisting of a solid wire essentially containing less than 0.3 % Ti with or without the addition of less than 0.

Abstract: A welding gun is provided having vacuum fume extraction means wherein the level of vacuum exerted at the arc welding zone is regulated to avoid extracting shielding gas supplied to the welding zone. The vacuum level is regulated by admitting sufficient air to a fume extracting passage provided within the gun to reduce the vacuum to the desired level.

Abstract: In a method of multiple electrode gas shielded arc welding wherein a plurality of electrodes are arranged along the welding seam line of a piece of metal to be welded and continuous gas shielded arc welding of the piece is accomplished simultaneously by the electrodes, the chemical composition of the electrode wire of the electrode or electrode group for depositing a preceeding layer or layers is selected to differ from that of the electrode wire of another electrode or electrode group for depositing a subsequent layer or layers, whereby the chemical composition of the weld metal made by the preceeding welding operation is brought near to that of the weld metal made by the following welding operation and thus the uniform properties are ensured for welding metals at the respective positions in the weld zone.

Abstract: A self-propelled arc welding device, which uses an inert gas within a primary zone to protect superheated metal from contact with atmospheric elements, is shielded with an outer compartment to protect against external air currents in the form of a portable shroud which closes off air currents along the work surface, at least partially. Particularly, for protecting girth welds in pipelines welded by a track-guided machine moving orbitally about the pipe, the compartment includes elements which make a substantially line contact with the pipe surface. The carriage which supports the welding device preferably carries the arc-enclosing shield. An observation window or opening for watching the arc is provided and free access to controls and adjustment means is permitted so that normal control operations are not hampered.

Abstract: The invention provides a purge unit for establishing a closed zone for an inert gas around a weld area. The purge unit is particularly adapted for use where a branch pipe is welded to a main pipe or header. The purge unit is inserted into an opening in the header and is then expanded to establish the closed zone around the inside of the weld area. An inert gas, in a volume much less than otherwise required, is then supplied through the unit into the zone to cover or blanket the inside of the weld area. After the weld is complete, the purge unit can be collapsed and withdrawn through the opening so as not to leave any material within the header which might cause contamination.

Abstract: This invention relates to a welding torch for practicing the gas metal arc process in the welding of thick square edged plates which are separated by a narrow gap. The torch includes a heat resistant tube for providing electrical contact with the moving wire, means for removing heat rapidly from the end of the torch, heat and electrical insulating means surrounding the contact means, and means for preventing weld spatter from adhering to the insulating means.

Abstract: A torch handle for use with a nozzle which includes a fume extracting orifice to remove fumes generated by welding or cutting includes a conduit within the handle for carrying the fumes to a vacuum pump and means for cooling the handle. In one embodiment, cooling is provided by mixing large quantitites of ambient air with the fumes in the vicinity of the nozzle. In another embodiment of the invention, ambient air is drawn into the handle and over the fume conduit and thereafter mixed with the fumes in the pipe leading to the vacuum pump. In a third embodiment, compressed air is directed into the handle from an internal source and passed over the fume carrying conduit within the handle. In a fourth embodiment, cooling water is passed over the surface of the fume extracting conduit within the handle.

Abstract: A plasma-MIG welding method and device in which a stream of oxidizing gas, such as argon plus 2% oxygen, is introduced into the plasma arc in the region of the plasma nozzle orifice. This improves the stability of the MIG arc, and higher welding currents can be used, especially with negative polarity on the electrodes and the plasma and MIG arcs.

Abstract: An alpha emitting isotope is positioned near the tip of a TIG welding electrode so that the alpha radiation can provide an ionized path between the electrode and the workpiece.

Abstract: A welding method including the steps of feeding a consumable electrode of at least 1/8 -inch diameter at a constant speed toward a parent metal to be welded, while maintaining, with electrical power at an amperage-voltage characteristic having a slope of 0 to 2 amperes/volt, a direct current arc between the consumable electrode and parent metal, and while maintaining a shielding gas flow at the arc and on molten metal, wherein the electrical power is connected between the consumable electrode and the parent metal in reverse polarity, wherein the speed of the consumable electrode toward the parent metal to be welded is controlled within plus or minus 1/2% of the desired speed, and wherein the power source providing the electrical power has a dynamic regulated output current of plus or minus 5%.

Abstract: A novel flux-cored welding wire for gas-shielded electric arc welding is described characterized by a shiny, metallic-appearing surface on a low carbon steel sheath and containing within its core as essential flux ingredients 6-20% ferro manganese, 6-20% ferro silicon, 1-20% manganous oxide, 1/2-5% of a flouride compound, and the balance rutile. The wire is especially useful in out-of-position welding to produce sound welds combining good strength and high notch toughness at subzero temperatures.

Abstract: Automatic fixed position pipe welding is carried out by gas-shielded electric arc welding with a novel flux-cored electrode wire having a low-carbon sheel sheath containing a core filling of, by weight, 16-17 percent ferro manganese, 10-11 percent ferro silicon, 1-4 percent manganous oxide, 1/2-1 percent potassium aluminum fluoride, and the balance rutile. The wire exterior is shiny and metallic-appearing, and the wire is configured to have folded-in edges.