- Email: [email protected]
Novel technique solves nuclear casting problem
international light weight and corrosion resistance, the investment cast termination connects a copper contact wire to the insulator. The component's complex design, including holes and gripping teeth, makes it suitable for the Micro Metalsmiths investment casting process, which allows minute detail to be cast which would otherwise require many machining operations. The technique used relies on the use of water-soluble cores and a water-soluble ceramic. The wax pattern is injected around the core and the core is removed by immersion in a water/weak acid bath. The wax shape is then invested in a mould made from a water-soluble ceramic slurry. After firing the ceramic, which melts out the wax, and pouring the metal,
news the ceramic mould is dissolved away, instead of being gritblasted or water blasted, techniques which would abrasively damage softer alloys, such as those based on aluminium, which would otherwise be suitable for investment casting. Re-entrant shapes are also tastable by this technique. The feasibility of sand and die castings were considered by Balfour Beatty, but were ruled out due to excessively high tooling costs and tool wear. The Micro Metalsmiths system keeps production costs to a minimum: dies have only to accept liquid wax or plastic under very light injectio pressures and since they do not wear out, re-tooling costs rarely occur.
Novel technique solves nuclear casting problem Problems posed by the manufacture of six 11 cwt castings in low carbon (0.03%max) 18/8 stainless steel were overcome by Lake & Elliot using novel techniques. By conventional methods, the main core of the .casting would have been supported top and bottom with holes which would afterwards have to be made good by welding - a process not acceptable to the customer, Beazer Manufacturing. Instead, a system was devised of making the core in two halves and supporting it by means of a steel tube running through its centre. The tube was drilled for venting hnd had tie-rods welded at the bottom to prevent the core falling away from it. After casting, the tube was provisionally cut off short and subsequently machined out. To promote early solidification, chills were inserted adjacent to the points where the tube passed through the casting and, to drive offpremature moisture at the early stage of casting, the tube was preheated. Exothermic sleeves were used to improve the yield, so that a casting could be produced from a 1t heat of steel. The finished castings measured 65in long with an outside diameter of 14in and an inside diameter of 10.5in.
Pultruded sections used in landing net constructions The incorporation of pultruded Glass Reinforced Plastics sections in a new landing net design has realised a number of advantages over nets of conventional aluminium construction. Developed by House, the new net frame is of a light yet touch construction, whilst being easy to dismantle for storage. Specially designed pultruded sections, manufactured by Pultrex, have their physical properties regulated to meet
158
MATERIALS & DESIGN Vol. 5 No. 4 AUGUST/SEPTEMBER 1984
news the ceramic mould is dissolved away, instead of being gritblasted or water blasted, techniques which would abrasively damage softer alloys, such as those based on aluminium, which would otherwise be suitable for investment casting. Re-entrant shapes are also tastable by this technique. The feasibility of sand and die castings were considered by Balfour Beatty, but were ruled out due to excessively high tooling costs and tool wear. The Micro Metalsmiths system keeps production costs to a minimum: dies have only to accept liquid wax or plastic under very light injectio pressures and since they do not wear out, re-tooling costs rarely occur.
Novel technique solves nuclear casting problem Problems posed by the manufacture of six 11 cwt castings in low carbon (0.03%max) 18/8 stainless steel were overcome by Lake & Elliot using novel techniques. By conventional methods, the main core of the .casting would have been supported top and bottom with holes which would afterwards have to be made good by welding - a process not acceptable to the customer, Beazer Manufacturing. Instead, a system was devised of making the core in two halves and supporting it by means of a steel tube running through its centre. The tube was drilled for venting hnd had tie-rods welded at the bottom to prevent the core falling away from it. After casting, the tube was provisionally cut off short and subsequently machined out. To promote early solidification, chills were inserted adjacent to the points where the tube passed through the casting and, to drive offpremature moisture at the early stage of casting, the tube was preheated. Exothermic sleeves were used to improve the yield, so that a casting could be produced from a 1t heat of steel. The finished castings measured 65in long with an outside diameter of 14in and an inside diameter of 10.5in.
Pultruded sections used in landing net constructions The incorporation of pultruded Glass Reinforced Plastics sections in a new landing net design has realised a number of advantages over nets of conventional aluminium construction. Developed by House, the new net frame is of a light yet touch construction, whilst being easy to dismantle for storage. Specially designed pultruded sections, manufactured by Pultrex, have their physical properties regulated to meet
158
MATERIALS & DESIGN Vol. 5 No. 4 AUGUST/SEPTEMBER 1984