Unglazed Fireproof Ware

material obtained, as a rule, from fired raw stock and formed from mixtures with inorganic or organic binders without subsequent firing. Magnesite-chromite unglazed fireproof ware, made of a mixture of magnesite and chromite fired at a temperature of 1600°–1650°C and subjected to a pressure of 80–130 meganewtons per sq m (MN/m²; 1 MN/m² ≈ 10 kilograms-force per sq cm) and sometimes reinforced with steel plates, is used for open-hearth and electrical steel-making furnaces, in the sintering zone of revolving furnaces for firing cement brick, and so forth. Ware made from fired dolomite with a resinous binder is used in steel-making converters. Forster-ite ware is used as checker in furnace regenerators. Magnesite vessels are used for casting steel. The compression strength of unglazed fireproof ware is 10–15 MN/m² (with chemical binders, up to 50–60 MN/m²), the porosity is 9–15 percent, and the volume change when heated to working temperatures is 3–5 percent. Unglazed fireproof ware is 5–15 percent less expensive than analogous fired ware and, in a number of cases, is not inferior to it in endurance.