GB756458A - Improvements in or relating to a method for producing welded joints - Google Patents

Abstract

756,458. Welding by fusion. KELLOGG CO., M. W. Nov. 2, 1953, No. 30241/63. Class 83 (4). In producing a weld between metal parts having thin edge portions, the portions are abutted and heat is applied to them to form a molten pool of metal extending the full depth of the portions and of constant width throughout its depth, and a gas blanket is provided against the root face, at a static pressure in excess of the static pressure on the front face, during fusion and solidification of the pool, the pool being held between the unfused ends of the portions and being shaped by the gas blanket. The excess gas pressure may be 0.0003-0.08 pounds per square inch gauge, the lower pressures resulting in convex root faces and the higher pressures in concave root faces. Two thin plates 10, 10, Fig. 1, are abutted over an open top box 11 and are clamped to a flange on the box while argon is supplied to one end of the box, small holes 21 being provided at the other end. An argonshielded tungsten electrode torch 41 with a filler rod 52 and using high frequency arc starting current is used for making tack welds by heating the seam at localized spots until the molten metal at each spot sinks. After tack welding, a series of overlapping welds are made in the same way to completely weld the seam. The torch may be continuously moved in the latter operation when one section of the molten pool is sinking as another section is being fused. Thick walled pipes 24, Fig. 2, are provided with thin, e.g. # or 1/32 inch thick lips which are butted and argon or helium is admitted to a chamber formed within the pipes by connected rubber plugs 25. Vent holes may be provided in one plug. After tack and seam welding as described, the groove between the pipes may be filled with weld metal. The pipes may be rotated on rollers during welding. Oxy-acetylene welding may be used and carbon, 18-8 austenitic and chrome steels, copper, nickel, aluminium, magnesium, titanium and their alloys may be welded.