method for welding unilateral steel, by means of a supporting base material and a body is located on the last

摘要

1407533 Welding by fusion WESTFALISCHE UNION AG 10 Oct 1973 [11 Oct 1972] 47308/73 Heading B3R In open, flux-submerged or gas-shielded arc, butt-joint root welding of flat or curved steel plates, a backing comprises one or more solid members 1 of "normal" glass (e.g. general purpose glass as used for windows, such as NaO-CaO-CoSiO 2 ), the members being supported by a heat conductive metal rail 2 (e.g. grooved or lipped and of copper) and having applied to the upper surface thereof as by water glass, a thin porous, granular layer, up to 2 mm. thick, of "normal" glass, slag or flux powder to space the molten pool from the glass backing. Such spacing may be such as to avoid harmful silicon increase in the bead and toallow the formation of a clearly defined projecting root bead. This granular layer may have introduced therein additional metals (e.g. Al, Mg, Ti, Mo, Cu and rare earth) or metal alloys, as powder or thin wire, e.g. to increase toughness. Radiation, e.g. light, from the root welding may be detected, by a pick-up moving with a welding head or a series of stationary pick-ups (as in Fig. 4, not shown) or visually (as in Fig. 5, not shown) through one or more apertures in the backing carrier, such detection being used to control the welding operation, as by control of current, voltage and welding speed. In welding with large air gaps, bare metal rods, small pieces of wire, steel shot or flux may be introduced into the seam before or during welding, the weld being bridged by an oscillating welding head. More than one arc, e.g. in tandem, may be employed.