GB887319A - Pressure welding metal members by interposition of friable substances therebetween - Google Patents

Abstract

887,319. Welding by pressure. REYNOLDS METALS CO. May 15, 1958 [May 15, 1957], No. 15718/58. Class 83 (4). In pressure - welding cold weldable metal members at least one of which is of aluminium, a layer or layers of total thickness of at least 0.00005 inch, of brittle or friable substance having a greater strength in compression than the members is interposed between the members and pressure is applied across the thickness of the members to shatter the layer or layers and effect welding of the members. Two aluminium strips 11, 12 anodized in aqueous electrolyte solution containing 15-18% sulphuric acid are overlapped, the films 16 having a composite thickness of at least 0.00005 inch, and spot-pressure tool 13 deforms the parts at point 15. Only one strip need be anodized, the other having a natural oxide film. Five aluminium members separated by layers of friable material may be similarly cold-pressure welded. Aluminium foil strip coated on each surface with an anodized or acid bath produced oxide layer, porcelain enamel or glass is disposed between two workpieces, e.g. naturally oxidized aluminium foil and a cold-pressure seam weld made, e.g. to form a foil bag. To assist in holding the strip spots of adhesive may be applied to the coatings. In a further embodiment two overlapped square pieces of aluminium sheet anodized to provide oxide films 0.00025 inch thick are cold-pressure spot welded. In another embodiment a sheet of aluminium is superimposed on a sheet of wirebrushed oxide free copper with a sheet of glass between them and spot-pressure is applied to shatter the glass and effect welding. Two aluminium sheets separated by a glass sheet may be welded. Electrically-conducting workpieces may be coated with an insulating friable substance, which may in turn be coated with silicone resin, and then cold-pressure welded without removing the insulation before welding. It is stated that some heat may be employed in welding, the friable layer may exceed 0.01 inch in thickness, the reduction in welding may be between 55 and 90% and that rollers or ribbed or elongated welding tools may be used. The term aluminium includes aluminium alloy.