| 摘要 |
1,150,005. Welding by pressure. NORTH AMERICAN AVIATION Inc. 9 Aug., 1966 [9 Aug., 1965], No. 35649/66. Heading B3R. A method of bonding a ferrous member to an aluminium or aluminium-based member comprises providing a tapered or knife edge on the ferrous member and pressing this edge into the aluminium member at elevated temperature. The process is preferably carried out with the joint faces under vacuum or in inert gas and the pressure and temperature may be maintained for a period of about 3 to 30 minutes. Temperatures of 750-1200‹ F. and pressures of about 20,000-35,000 p.s.i. are envisaged. In order to prevent undesirable intermetallic diffusion occurring a barrier metal comprising one or more of the following: tantalum, niobium, chromium, gold, silver, nickel, tungsten and molybdenum may be interposed between the ferrous and aluminium members. The barrier metal may be applied as a separate foil or be coated on either the ferrous or aluminium member. The ferrous member may be of stainless steel and comprises at least 50% iron while the aluminium based member may be of an alloy containing 4-12% aluminium oxide dispersed in aluminium. The invention is particularly applicable to the joining of tubular ferrous and aluminium members 2, 4, the former having a knife edge 6, the members being supported by an outer die 10 and inner mandrel 12 on a die base 14. The assembly is heated by an induction coil 16 and pressure applied by an hydraulic press 18. The whole apparatus is enclosed in a vacuum or inert gas enclosure during the bonding process. |
