METHOD FOR MANUFACTURE OF REMOVABLE INVESTMENT CASTINGS Russian patent published in 2002 - IPC

FIELD: mechanical engineering. SUBSTANCE: method involves manufacturing investment casting from boric acid pellets of 0.01-0.3 mm fraction clad with investment composition. Volumetric ratio of investment material components, %: investment composition 10-65 and boric acid 35-90. Investment material is dosed in casting mold in an amount providing manufacture of investment castings with 1.5-3% porosity. Investment material is pressed without preliminary heating by aligning casting mold detachment surfaces under vacuum of -0.1 MPa. During pressing powdered investment material is caked without substantial phase deformation processes and with formation of open capillary porosity compensating expansion of investment casting during heating thereof in the process of melting from enclosure. EFFECT: increased dimensional and geometric precision of investment castings and ingots. 1 tbl