Improvements in methods of producing moulds for 'cire-perdue' precision casting

摘要

741,601. Flasks. REGIE NATIONALE DES USINES RENAULT. July 11, 1952 [Sept. 4, 1951], No. 17612/52. Class 83 (1). Moulds; mould materials.-In a method of making moulds by the " lost-wax " process, the refractory compound for the mould is poured into a cylinder 4 of metallic grating or heavily-perforated sheet metal which is rendered fluid-tight by wrapping it with flexible waterproof material 5 such as paper, rubber, &c., which is removed after setting so that the mould may be dried rapidly through the perforations of the cylinder 4. The base of the cylinder is sealed, as by melted wax 6, to a wax plate 3 supported on a vibrating table 7. The investment may comprise 6 kg. of silica sand grains, 150 to 400 microns in size, and 1,500 c.c. of binder which is made at the time of use and consists of 200 c.c. of sodium silicate (8 per cent of Na 2 O and 28 per cent of SiO 2 ), 20 grams of ammonium nitrate and 800 c.c. of water.