METHOD OF MAKING A CERAMIC MOLD FOR CASTING ON MOLTEN PATTERNS Russian patent published in 2020 - IPC B22C1/02 B22C9/12 

FIELD: technological processes.

SUBSTANCE: invention relates to metallurgy. Refractory coating is applied on the model unit and layers of refractory suspensions are formed. Each layer is sprinkled with grainy electrocorundum in sand-bulker and dried, then the wax model is removed and the mold is annealed. Facial layer suspension has the following composition, wt%: acidic water-colloidal binder 43.0–47.0, surface modifier – cobalt aluminate 4.0–12.0, concentrate disthen-sillimanite powdery 45.0–49.0. Face layer is dried on conveyor. Refractory suspension of the following layers has the following composition, wt%: high-alkali water-colloidal binder 51.0–55.0, powdered-sillimanite concentrate 45.0–49.0. Subsequent layers are dried in climatic chamber at air humidity 30–32 %, temperature 20–22 °C and air flow rate of 4.0–5.0 m/s for 3–4 hours. Then mold is dried in climatic chamber for not less than 12 hours and calcined according to mode preventing formation of α-cristobalite: mold loading into cold furnace, heating to 740–750 °C at rate ≤200 °C/h, aged at 750–740 °C for 3 hours, cooling with furnace to temperature of 100–20 °C.

EFFECT: higher durability of suspension and automated production of ceramic molds.

4 cl, 3 ex