... material, electric power and machine-building Main properties of water-free gun clay: Compression strength, at normal tem, MPa110 ... 1.4Linear change rate1450 degree centigrade 3h0--1.5 Index of plasticity, %15--40 Apparent porosity, %30--40Refractoriness, ... refractory products, including prefabricated iron runner blocks, castable refractory for iron runner, water-free gun clay, composite iron pellets, ...