GB1505098A - Method and apparatus for welding tubular members along a circumferential seam - Google Patents

Abstract

1505098 Welding by fusion WESTING- HOUSE ELECTRIC CORP 10 Dec 1975 50571/75 Heading B3R [Also in Division G3] In a method and apparatus for welding circular tubular members (e.g. nuclear reactor pressure vessel sections) along a circumferential seam 16 a plurality of welding stations are provided at positions spaced symmetrically around the seam. The welding parameters are controlled automatically according to preset instructions from the operator on control panels 132 and 134 or directly by the operator during the welding, by the circuitry depicted in Figs. 13-18 (not shown). The heat input of the, e.g. tungsten/inert gas torch 54, is maintained at a preset value as is the feed rate of the filler wire 130 and its temperature, it being preheated by an A.C. current. An oscillator 118 may be provided to oscillate the torch in accordance with predetermined excursion and dwell settings, as it moves relative to the weld seam and tracking arm 110 automatically maintains the torch in alignment with the seam. Typically a minimum heat input and hot wire feed rate is initially established, built up at a predetermined rate to a predetermined maximum to form an initial taper, maintained at this level as the seam moves relative to the welding station and finally tapered off again to complete a smooth weld.