IMPROVEMENT OF PRODUCTION OF THIN-WALLED CAST PARTS BASED ON SPECIAL MOLD MATERIALS

Abstract

Molds made from fast-hardening plastic mixtures on liquid glass are used to obtain large castings from cast iron, steel, and non-ferrous alloys weighing more than 5 tons with wall thicknesses up to 200-300 mm under single and serial production conditions. In this case, the liquid-glass mixture is used as a facing mixture, applying it to the model with a layer 50-70 mm thick and filling the rest of the flask volume with a filling sand-clay mixture. Thick-walled shell molds and rods are also made from liquid glass mixtures, assembled in a metal jacket with backfill, for example, from sand, coarse steel or cast iron shot, fireclay chips. The liquid-glass form after the model is removed is chemically cured by purging with carbon dioxide. The resulting silicic acid gel binds the sand grains during curing. The curing time, depending on the intensity of the CO2 purge and the dimensions of the mold, averages 6-7 minutes