ARC WELDING ELECTRODE ARRANGEMENTS

1283390 Welding by fusion BABCOCK & WILCOX CO 30 Oct 1969 [31 Oct 1968] 53191/69 Heading B3R In submerged-are or gas-shielded welddeposition of one or more bands of cladding 14 on a workpiece 18 using a plurality of simultaneously operative consumable electrodes, e.g. 31-36, distributed widthwise of the band and moved relatively to the workpiece, an end electrode 36 is positioned so as to lag behind a line-abreast remainder of the electrodes to improve the junction of adjacent bands by avoiding the undesirable tendency of the cladding at the edge 15A to roll over above or overhang the adjacent workpiece surface. Side-by-side or helical bands may be deposited respectively on a flat or curved or on a cylindrical workpiece. For deposition of a first band only, the electrode 31 also may be disposed in a lagging position, using a displaceable or, as shown and in Fig. 3A (not shown), replacement welding head part. For deposition of subsequent bands, preferably, for further junction improvement, the electrode 31 is operated at reverse (+) polarity whilst the electrodes 32-36 are at straight (-) polarity; and preferably, also, the electrode 31 is positioned above, or to overlap, the edge of the previously deposited band. To avoid the necessity for alternative polarity connections for the electrode 31, the first band may be deposited using electrodes 32-36 only, the electrode 31 not being fed. Either the electrodes or the workpiece may be moved and automatic indexing means may be used for lateral positioning. The electrodes 31-36 may be laterally oscillated by means 50.