GB1383304A - Welding consumables - Google Patents

Abstract

1383304 Welding consumables; welding by fusion BRITISH OXYGEN CO Ltd 9 Feb 1972 [9 Feb 1971] 4265/71 Headings B3A and B3R [Also in Division C7] A method of manufacturing a welding consumable comprises inserting core material into a ductile tubular sheath which has a continuous circumference and which is open at one end, closing the open end of the sheath, and hot working the closed sheath to reduce its outside dimensions by a required extent and to sinter or partially sinter any particulate or fibrous material in the core material, wherein the sheath forms part of the finished welding consumable. The consumable may be processed by hotextruding, forging, hot-rolling or swaging. Hotrolling may be carried out in two stages. Firstly, the consumables cross-sectional area may be reduced by over 60% in one rolling operation to partially sinter the core, the ends are then cut off followed by a further hot-rolling operation. The core material may also be compacted before the hot-rolling stage. The sheath which may be made by any conventional tube-making process comprises stainless steel, mild steel, nickel or nickel alloy, copper or copper alloy, cobalt alloy, or aluminium or aluminium alloy, with the plugs being generally of the same material and having passages therethrough to allow escape of evolved gas during manufacture if required. The core may comprise metal powders 4, Fig. 1, flux powders, metal or flux fibres, and even tubular wires 16, Fig. 5, or solid wires (10), Fig. 3 (not shown). Some of the tubular wires may be filled with powder. Three types of consumables are described in detail: (i) those containing elements which are transferred from the consumable to the weld metal without significant oxidation and which do not require special precautions to reduce oxidation during manufacture or welding. Binders may be used for pre-agglomeration of the metal powders; (ii) those including special alloying elements difficult to introduce into solid wires and which are used for their deoxidation and scavenging properties. Suitable core materials include aluminium, calcium, titanium, zirconium, magnesium, cerium and the rare earth metals which may be present in encapsulated form; (iii) those intended for self-shielded are welding, the cores of which include elements transferable from the consumable to the weld metal without significant oxidation, e.g. chromium, molybdenum, manganese, silicon, nickel, cobalt; elements having a high affinity for oxygen and nitrogen, e.g. aluminium, titanium, magnesium, zirconium, cesium and the rare earth metal; residual fluxes for protecting and wetting the weld. The core material may be in solid or tubular form, or powdered. Typical fluxes used are oxides, and/or fluorides of alkalies, alkaline earth metals and rare earth elements, aluminium, silicon, titanium, magnesium, zirconium and calcium, and carbonates of alkaline earth metals. A consumable for the self-shielded welding of mild steel comprises a tubular sheath having a core consisting of a bundle of tubular wires made by enfolding metal and flux powders in a mild steel strip. The sheath is sealed by welding on perforated plugs of mild steel and the consumable is then processed by hot-rolling and drawing. The metal and flux powders in the core wires constitute approximately 20 wt. per cent of the consumable. Examples of core compositions of the various types of consumables are:-