Ceramic mould for metal casting - has specified porosity smooth contact surface and is high temp. resistant

摘要

A ceramic mould for metal casting, e.g. centrifugal casting, which may include the use of casting sand and using clay with an Al2O3 content of about 40%, mixed with binder and granular material, has a porosity of 20-30%, a heat strength (DIN 51064) at 1450 degrees C, 50 N/cm2 a softening point under pressure (DIN 51053) at a point t 0.5 of 1300 degrees C are at a point t3, 1500 degrees C, and a temp. reversal stability (DIN 1068) for a min. of 50 launchings. The surfaces in contact with the hot metal has a smooth coating between 0.5 and 5 mm or between 1.5 and 3 mm thick, is heat resistant to 1520 - 1605 degrees C and a heat conductivity of between 0.232 and 1.16 W/mK.