GB794886A - Electric arc welding - Google Patents

Abstract

794,886. Welding by fusion. AIR REDUCTION CO., Inc. May 25, 1956 [May 27, 1955], No. 16259/56. Class 83 (4). Shielding gas for use in gas shielded arc welding is obtained by expanding a jet of liquefied gas to the gaseous state in the vicinity of the arc. The gas is carbon dioxide and may be partially in the form of snow after expansion. The expanding carbon dioxide cools the welding torch. A welding torch, Fig. 2, through which is fed a consumable electrode E, has a copper contact tube 30. Liquid carbon dioxide is fed from a manifold 33 through tubes 34 soldered in recesses in the contact tube 30 to orifices of say 0.01 inch diameter in a plate 38. In a modification, the liquid is fed by a single tube to an orificed manifold at the lower end of the torch, and a gas nozzle is provided around the electrode E. The contact tube may have a projecting enlarged end 61, Fig. 9, to increase cooling of the torch. In a modification, Fig. 7, the liquid supply tubes 51 extend down the exterior of the torch and pass through apertures in a nozzle 52 to direct gas against the nozzle and tangentially of the electrode. In a further modification, Figs. 11, 12, the contact tube 75 is formed with passages 76 through which is passed an inert gas such as argon or helium to form an inner shielding layer whilst liquid carbon dioxide in tubes 70 is expanded through orifices 72 to supply an outer shielding layer. The electrode E may be consumable or non-consumable.