GB712271A - Improvements in the preparation of aluminium wire for use in the gas-shielded arc welding method - Google Patents

Abstract

An aluminium or aluminium alloy wire for use as a consumable p electrode in the gas shielded arc welding of aluminium is prepared by removing all hydrocarbons, moisture and moisture adsorbing oxide film therefrom and packaging the wire in a substantially moisture-proof container while the wire is still substantially free of any hydrogen-containing compound. All moisture, hydrocarbons such as oil and grease and hydrated oxide film are removed from the wire. An alkaline bath containing sodium carbonate, trisodium phosphate and sodium hydroxide may be used to remove oil, grease and hydrated oxide film. The wire is then immersed in an acid, e.g. nitric, nitric-hydrofluoric or chromic based to brighten it and it is rinsed and dried. An alkaline bath, e.g. 3 per cent. sodium carbonate and 3 per cent. sodium phosphate with an inhibitor, e.g., pyridine or aniline or a vapour degreaser, e.g. trichlorethylene, perchlorethylene, carbon tetrachloride or benzol may be used to remove oil and grease and an acid bath, e.g. of nitric, phosphoric and acetic acids to remove the oxide film. The acid bath may be replaced by a solution of caustic soda, zinc oxide and water in which the oxide film is dissolved to expose the aluminium which on dissolving is replaced by zinc. The zinc is removed in a nitric acid bath. Stainless steel brushes may be used to mechanically remove the oxide film. Specification 712,238 is referred to.