METHOD FOR INVESTMENT CASTING Russian patent published in 1999 - IPC

FIELD: manufacture of turbine blades of high-temperature alloyed steel by investment casting. SUBSTANCE: ceramic refractory shell is lined by flexible heat-insulating material of refractory fibre of system Al₂O₃-SiO₂. Thickness S of flexible heat-insulating material is alternately varied in height, depending on value R of casting wall section area-to-section perimeter ration. For a thin casting section at a wall thickness of 0.5 mm maximum value S= 250R is selected, and for a thick casting section at a wall thickness up to 50 mm - minimum value S=1R. The chamber is filled with loose refractory material, and a ceramic shell mould is installed on it. The chamber walls are cooled down, maintaining their constant temperature. EFFECT: reduced consumption of allow per casting, reduced spoilage of casting, production of casting without any defects of shrinkage origin with preset structure, enhanced mechanical properties of casting due to oriented crystallization. 3 cl, 2 dwg, 1 tbl, 2 ex